U.S. patent application number 16/491092 was filed with the patent office on 2020-03-19 for light protection package including monolayer container and monolayer closure.
The applicant listed for this patent is THE CHEMOURS COMPANY FC, LLC. Invention is credited to DENISE CONNER, CHERYL MARIE STANCIK.
Application Number | 20200087047 16/491092 |
Document ID | / |
Family ID | 62044984 |
Filed Date | 2020-03-19 |
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United States Patent
Application |
20200087047 |
Kind Code |
A1 |
STANCIK; CHERYL MARIE ; et
al. |
March 19, 2020 |
LIGHT PROTECTION PACKAGE INCLUDING MONOLAYER CONTAINER AND
MONOLAYER CLOSURE
Abstract
A new light protective package which includes a monolayer
container and a removable and re-sealable monolayer closure,
wherein both the monolayer container and the monolayer closure have
an LPF value of at least about 20.
Inventors: |
STANCIK; CHERYL MARIE;
(KENNETT SQUARE, PA) ; CONNER; DENISE; (NEWARK,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THE CHEMOURS COMPANY FC, LLC |
WILMINGTON |
DE |
US |
|
|
Family ID: |
62044984 |
Appl. No.: |
16/491092 |
Filed: |
March 30, 2018 |
PCT Filed: |
March 30, 2018 |
PCT NO: |
PCT/US2018/025372 |
371 Date: |
September 4, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62479845 |
Mar 31, 2017 |
|
|
|
62575728 |
Oct 23, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65D 81/30 20130101;
B65D 85/80 20130101 |
International
Class: |
B65D 81/30 20060101
B65D081/30; B65D 85/80 20060101 B65D085/80 |
Claims
1. A package comprising a monolayer container and a removable and
re-sealable monolayer closure, wherein both the monolayer container
and the monolayer closure have an LPF value of at least about
20.
2. The package of claim 1, wherein the monolayer container and the
monolayer closure have the same LPF value.
3. The package of claim 1, wherein the package further comprises a
removable seal covering an opening in the monolayer container.
4. The package of claim 1, wherein the LPF is at least about
30.
5. The package of claim 1, wherein the LPF is at least about
40.
6. The package of claim 1, wherein the LPF is at least about
50.
7. The package of claim 1, wherein the LPF is at least about
60.
8. The package of claim 1, wherein the LPF is at least about
80.
9. The package of claim 1, wherein the LPF is at least about
100.
10. The package of claim 1, wherein at least one of the monolayer
container and monolayer closure comprises titanium dioxide.
11. The package of claim 1, wherein at least one of the monolayer
container and monolayer closure comprises at least one color
pigment.
12. The package of claim 1, wherein at least one of the monolayer
container and monolayer closure comprises plastic.
13. The package of claim 1, wherein the monolayer container and the
monolayer closure comprise plastic.
14. The package of claim 1, wherein the package contains dairy
product.
15. The package of claim 1, wherein the package contains liquid
dairy product.
16. The package of claim 15, wherein the liquid dairy product
comprises milk.
17. Light protection monolayer closure comprising a top portion
having a thickness of at least about 50 mil.
18. The closure of claim 17, wherein the top portion thickness is
from about 50 mil to about 70 mil.
19. The closure of claim 18, wherein the top portion thickness is
from about 50 mil to about 60 mil.
20. The closure of claim 17, wherein the closure top portion has an
LPF of at least about 50.
21. The closure of claim 17, wherein the closure is white.
22. The closure of claim 17, wherein the closure comprises
TiO.sub.2.
23. The closure of claim 22, wherein the closure further comprises
one or more pigments.
24. The closure of claim 23, wherein the one or more pigment is
yellow pigment.
25. The closure of claim 23, wherein the one or more pigment is
black pigment.
26. The closure of claim 17, wherein the closure comprises
plastic.
27. The closure of claim 26, wherein the closure comprises at least
one material selected from the group consisting of HDPE, LLPE, PET,
and PS.
Description
BACKGROUND OF THE INVENTION
[0001] Certain compounds and nutrients contained within packages
can be negatively impacted by exposure to light. Many different
chemical and physical changes may be made to molecular species as a
result of either a direct, or indirect, exposure to light, which
can collectively be defined as photochemical processes. As
described in Atkins, photochemical processes can include primary
absorption, physical processes (e.g., fluorescence,
collision-induced emission, stimulated emission, intersystem
crossing, phosphorescence, internal conversion, singlet electronic
energy transfer, energy pooling, triplet electronic energy
transfer, triplet-triplet absorption), ionization (e.g., Penning
ionization, dissociative ionization, collisional ionization,
associative ionization), or chemical processes (e.g.,
disassociation or degradation, addition or insertion, abstraction
or fragmentation, isomerization, dissociative excitation) (Atkins,
P. W.; Table 26.1 Photochemical Processes. Physical Chemistry, 5th
Edition; Freeman: New York, 1994; 908.). As one example, light can
cause excitation of photosensitizer species (e.g., riboflavin in
dairy food products) that can then subsequently react with other
species present (e.g., oxygen, lipids) to induce changes, including
degradation of valuable products (e.g., nutrients in food products)
and evolution of species that can adjust the quality of the product
(e.g., off-odors in food products).
[0002] As such, there is a need to provide packaging with
sufficient light protection properties to allow the protection of
the package content(s) and sufficient mechanical properties to
withstand shipping, storage, and use conditions.
[0003] The ability of packages to protect substances they contain
is highly dependent on the materials used to design and construct
the package (reference: Food Packaging and Preservation; edited M.
Mathlouthi, ISBN: 0-8342-1349-4; Aspen publication; Copyright 1994;
Plastic Packaging Materials for Food; Barrier Function, Mass
Transport, Quality Assurance and Legislation: ISBN 3-527-28868-6;
edited by O. G Piringer; A. L. Baner; Wiley-vch Verlag GmBH, 2000,
incorporated herein by reference). Preferred packaging materials
are designed with consideration for the penetration of moisture,
light, and oxygen often referred to as barrier characteristics.
[0004] Light barrier characteristics of materials used for
packaging are desired to provide light protection to package
contents. Methods have been described to measure light protection
of a packaging material and characterize this protection with a
"Light Protection Factor" or (LPF) as described in commonly owned
U.S. Pat. No. 9,638,679 "Methods for producing new packaging
designs based on photoprotective materials", the subject matter
which is hereby incorporated by reference in its entirety.
[0005] Titanium dioxide (TiO.sub.2) is frequently used in plastics
food packaging layer(s) at low levels (typical levels of 0.1 weight
% to 5 weight % ("weight %" is abbreviated as "wt %" hereinafter)
of a composition) to provide aesthetic qualities to a food package
such as whiteness and/or opacity. In addition to these qualities,
titanium dioxide is recognized as a material that may provide light
protection of certain entities as described in, for example, U.S.
Pat. Nos. 5,750,226; 6,465,062; and US 20040195141.
[0006] Useful packaging designs are those that provide the required
light protection and functional performance at a reasonable cost
for the target application. The cost of a packaging design is in
part determined by the materials of construction and the processing
required to create the packaging design.
[0007] Milk packaging is an application where there is a benefit
for light protection in packages to protect milk from the negative
impacts of light exposure. Light exposure to milk may result in the
degradation of some chemical species in the milk; this degradation
results in a decrease in the nutrient levels and sensory quality of
the milk (e.g., "Riboflavin Photosensitized Singlet Oxygen
Oxidation of Vitamin D", J. M. King and D. B. Min, V 63, No. 1,
1998, Journal of Food Science, page 31). Hence protection of milk
from light with light protection packaging will allow the nutrient
levels and sensory quality to be preserved at their initial levels
for extended periods of time as compared to milk packaged in
typical packaging that does not have light protection (e.g.,
"Effect of Package Light Transmittance on Vitamin Content of Milk.
Part 2: UHT Whole Milk." A. Saffert, G. Pieper, J. Jetten;
Packaging Technology and Science, 2008; 21: 47-55).
[0008] Additionally, multilayered structures are seen as a means to
achieve light protection qualities in package designs. Typically,
more than one layer of material is required for adequate protection
of food from light and mechanical damage. For example, Cook et al.
(U.S. Pat. No. 6,465,062) present a multilayer packaging container
design to achieve light barrier characteristics with other
functional barrier layers. Problems associated with multilayered
packaging structures are they require more complex processing,
additional materials for each layer, higher package cost, and risk
delamination of layers. Deficiencies of multilayer designs and
benefits of monolayer designs are discussed in US 20040195141 in
section [0022] and [0026]. Moreover, state of the art caps
comprising two or more layers of materials, such as a foil seal or
light block liner, can achieve suitable light protection. However,
these designs are deficient as the foil seal or liner layer may be
removed or damaged after the package is opened by the consumer.
These additional layers may be perceived by consumers as only part
of the product sealing function. Thus, the consumer may remove
them, perhaps so the layers or pieces of the layer do not fall into
the product. Upon removal of such additional layer(s) the cap will
not retain the light protection benefit provided by the layer(s)
after the product is opened and the layer(s) is removed. Thus, such
layer(s) may be used for sealing or other functions but are not a
part of the light protection performance of the cap through
consumer use.
[0009] Thus, there is a commercial need to create a monolayer food
package that achieves, or exceeds, the light protection and
mechanical strength properties of a multilayer package.
[0010] The present invention provides solutions to the
above-identified deficiencies in the art by providing monolayer
containers and monolayer closures that provide sufficient light
protection and mechanical strength.
SUMMARY OF THE INVENTION
[0011] The invention comprises a light protection package that
comprises a monolayer container and monolayer closure (e.g., a cap)
that considers all portions of the light exposed package design,
including all areas of the package that allow the potential for
light exposure to the product contained within the package. For
example, a light protection package according to the invention can
be a light protection dairy container (e.g., a bottle) and
removable and re-sealable closure (e.g., a cap). For optimal light
protection performance, the container and closure can have
substantially the same light protection performance or
alternatively, when the light protection performance of the
container and closure are different, the desired light protection
performance should be met by the minimum performance level for
either the container or closure.
[0012] The invention comprises a light protective package that
comprises a monolayer container and a monolayer closure. The
monolayer container and/or monolayer closure can comprise TiO.sub.2
particles. Moreover, the monolayer container and/or monolayer
closure can further comprise at least one color pigment. The
TiO.sub.2 particles and at least one color pigment can be dispersed
throughout the container material and/or closure. The package has
superior light protection properties while maintaining necessary
mechanical properties. The monolayer container and/or monolayer
closure can have a light protection factor ("LPF") value of 20 or
greater, preferably greater than 30, more preferably greater than
40, more preferably greater than 50, more preferably greater than
60, more preferably greater than 80, and even more preferably
greater than 100.
[0013] In an aspect of the invention the monolayer closure
comprises a top portion that is a sufficient thickness produced
with light protection materials to provide light protection
performance to the closure. In an aspect of the invention the
monolayer closure top portion can have a thickness of at least
about 50 mils.
BRIEF DESCRIPTION OF THE FIGURES
[0014] FIG. 1 is a schematic drawing of a package according to the
invention.
[0015] FIG. 2 is a schematic drawing of a package according to the
invention.
[0016] FIG. 3 is a schematic drawing of a package according to the
invention.
[0017] FIG. 4 is a schematic drawing of a package according to the
invention.
[0018] FIG. 5 is a schematic drawing of a removable seal.
[0019] FIG. 6 is a graph of data obtained in Example 1.
[0020] FIG. 7A is a schematic illustration of the sample holder
used to determine the light protection factor ("LPF") according to
the teachings of U.S. Pat. No. 9,638,679.
[0021] FIG. 7B is a schematic illustration of a modified sample
holder used to determine the LPF of the top portion of plastic
caps.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0022] The invention comprises a light protection package that
comprises a monolayer container and monolayer closure (e.g., a cap)
that considers all portions of the light exposed package design,
including all areas of the package that allow the potential for
light exposure to the product contained within the package. For
example, a light protection package according to the invention can
be a light protection dairy container (e.g., a bottle) and
removable and re-sealable closure (e.g., a cap). For optimal light
protection performance, the container and closure can have
substantially the same light protection performance or
alternatively, when the light protection performance of the
container and closure are different, the desired light protection
performance should be met by the minimum performance level for
either the container or closure.
[0023] In this disclosure "comprising" is to be interpreted as
specifying the presence of the stated features, integers, steps, or
components as referred to, but does not preclude the presence or
addition of one or more features, integers, steps, or components,
or groups thereof. Additionally, the term "comprising" is intended
to include examples encompassed by the terms "consisting
essentially of" and "consisting of." Similarly, the term
"consisting essentially of" is intended to include examples
encompassed by the term "consisting of."
[0024] In this disclosure, when an amount, concentration, or other
value or parameter is given as either a range, typical range, or a
list of upper typical values and lower typical values, this is to
be understood as specifically disclosing all ranges formed from any
pair of any upper range limit or typical value and any lower range
limit or typical value, regardless of whether ranges are separately
disclosed. Where a range of numerical values is recited herein,
unless otherwise stated, the range is intended to include the
endpoints thereof, and all integers and fractions within the range.
It is not intended that the scope of the disclosure be limited to
the specific values recited when defining a range.
[0025] In this disclosure, terms in the singular and the singular
forms "a," "an," and "the," for example, includes plural references
unless the content clearly dictates otherwise. Thus, for example,
reference to "TiO.sub.2 particle", "a TiO.sub.2 particle", or "the
TiO.sub.2 particle" also includes a plurality of TiO.sub.2
particles. All references cited in this patent application are
herein incorporated by reference.
[0026] Monolayer is defined as a structural component of the
package (e.g., the container and the closure (the closure may
include threaded portion to assist in re-sealing the closure and
container)) that is comprised of a single layer of material. The
material in its cross section does not have differential layers
with different compositions or functional properties. The monolayer
is structural as it contains the contents of the package, however
the package may be rigid (e.g., like a plastic bottle) or flexible
(e.g., like a plastic pouch) or a combination of rigid and flexible
portions.
[0027] Layers may be applied to the package components that are not
structural. For example, decorative sleeves, stickers, wraps or
print may be applied to cover portions of the package to provide
branding, consumer information, and adjust the package texture and
appearance. These layers are considered non-structural layers and
thus a package comprising one or more components that are not
structural is still considered monolayer in its structural design
according to the invention.
[0028] A co-extruded package structure is not considered a
monolayer package design according to the invention.
[0029] The removable and re-sealable closure (such as a bottle cap,
which may comprise threads) may contain an optional insert which,
if it can be readily removed, is also considered a layer that is
nonstructural. For example, a cap may contain a layer to facilitate
sealing of the package when the cap threads are engaged with a
corresponding threaded portion of the container. Moreover, a cap or
container may include a seal (e.g., foil or plastic) that is
removed and discarded for normal consumer use of the package.
[0030] If a package container or closure contains a seal that is
removed irreversibly for removal of the product from the package,
then the container or closure is still considered to be a monolayer
design. This seal that is removed is insufficient as a light
protection layer as it is only available for light protection until
the seal is removed. For example, a seal layer such as a plastic
seal or a foil seal would be considered irreversibly removed
layers.
[0031] If the seal is integrated into the cap it is not a monolayer
cap according to the invention. Further if the cap contains another
functional layer, such as an integrated oxygen scavenger layer or
additional gasket-like material to improve the seal, it is not a
monolayer cap. Aesthetic layers on the cap such as printed ink or
stickers or partial coverage such as tamper evident rings can be
used with a monolayer cap as the primary cap is still a single
complete layer of material.
[0032] The invention comprises a light protective package that
comprises a monolayer container and a removable and re-sealable
monolayer closure (e.g., a cap). The monolayer container and/or
monolayer closure can comprise TiO.sub.2 particles. Moreover, the
monolayer container and/or monolayer closure can further comprise
at least one color pigment. The TiO.sub.2 particles and at least
one color pigment can be dispersed throughout the container
material and/or closure. The package has superior light protection
properties while maintaining necessary mechanical properties. The
monolayer container and/or closure can have a light protection
factor ("LPF") value of 20 or greater, preferably greater than 30,
more preferably greater than 40, more preferably greater than 50,
more preferably greater than 60, more preferably greater than 80,
and even more preferably greater than 100. A detailed description
of LPF and measuring LPF values is described in commonly owned U.S.
Pat. No. 9,638,679 "Methods for producing new packaging designs
based on photoprotective materials" and U.S. Pat. No. 9,372,145
"Devices for determining photoprotective materials" the subject
matter of both patents is incorporated herein by reference.
Additional information may be found in the example sections of
these patents. LPF values used herein are determined according to
the teachings in these two patents.
[0033] The invention also comprises a monolayer closure comprising
a top portion and side wall(s) portion. The closure top portion is
a sufficient thickness produced with light protection materials to
provide light protection performance to the closure. The closure
top portion can have an LPF value of 20 or greater, preferably
greater than 30, more preferably greater than 40, more preferably
greater than 50, more preferably greater than 60, more preferably
greater than 80, and even more preferably greater than 100. The
monolayer closure additionally comprises light protection TiO.sub.2
materials. The monolayer closure provides suitable light protection
performance in the closure top portion while overcoming injection
molding closure production process challenges presented with the
use of light protection materials at higher levels. This allows the
processing performance of the injection molding equipment used to
produce the closures to be maintained and the mechanical features
(e.g., the threads on a screw top closure) of these closures to be
produced with their desired functionality (e.g., sealing
performance).
[0034] The monolayer closure can be used in conjunction with any
container (e.g., a bottle). However, in an aspect of the invention
the monolayer closure can be used in conjunction with a light
protection container according to the present invention. Where the
closure threads or side wall(s) engage or seal with the container,
the primary container can provide light protection performance;
however, as a monolayer, the top portion of the closure does not
have any additional package layer to provide light protection and
thus it must provide the light protection performance. Suitable
light protection performance is achieved with the monolayer closure
of the invention which comprises a thicker closure top portion
(relative to the thickness of the cap side wall(s)) wherein light
protection TiO.sub.2 materials are provided throughout the closure.
In an aspect of the invention the closure comprises a top portion
having a thickness of at least about 50 mil.
[0035] Although the closure of the present invention can be used
with any suitable container, preferred containers include the
containers of the present invention and additionally include the
containers disclosed in commonly owned US20160083554,
WO2016/196529, and PCT patent application PCT/US2017/066105, the
subject matter of each is hereby incorporated by reference in their
entirety.
[0036] Referring to the Figures, aspects of the invention will be
described. FIGS. 1-4 demonstrate various possible packages 1
according to the invention, where the packages 1 comprise monolayer
container (e.g., a bottle) 2 and monolayer closure (e.g., a cap) 3.
As shown, closures 3 are removable and re-sealable. FIGS. 2 and 4
further show additional, non-structural layers 5, such as product
labels that may include consumer information, brand name, etc. The
monolayer container can also be provided with a removable seal 4
over an opening in the monolayer container. FIG. 5 demonstrates
such an embodiment that includes a monolayer container 2 with
removable seal 4. The removable seal 4 can be constructed of any
suitable material, such as plastic or foil, and may or may not be
provided with a pull-tab as shown.
[0037] The titanium dioxide (and optionally at least one color
pigment) can be dispersed and processed in package production
processes by incorporating a masterbatch, and preferably processed
into a package using blow molding methods and/or injection molding.
The masterbatch can be solid pellets. The TiO.sub.2 (and optional
color pigment) could also be delivered in other forms, such as in a
liquid delivery form and do not have to be delivered in one single
masterbatch formulation.
[0038] In an aspect of the invention the TiO.sub.2 particles can be
coated with a metal oxide, preferable alumina, and then an
additional organic layer. The treated TiO.sub.2 is an inorganic
particulate material that can be uniformly dispersed throughout a
polymer melt, and imparts color and opacity to the polymer melt.
Reference herein to TiO.sub.2 without specifying additional
treatments or surface layers does not imply that it cannot have
such layers.
[0039] It is preferred that the metal oxide is selected from the
group consisting of silica, alumina, zirconia, or combinations
thereof. It is most preferred that the metal oxide is alumina. It
is preferred that the organic coating material on the TiO.sub.2 is
selected from the group consisting of an organo-silane, an
organo-siloxane, a fluoro-silane, an organo-phosphonate, an
organo-acid phosphate, an organo-pyrophosphate, an
organo-polyphosphate, an organo-metaphosphate, an
organo-phosphinate, an organo-sulfonic compound, a
hydrocarbon-based carboxylic acid, an associated ester of a
hydrocarbon-based carboxylic acid, a derivative of a
hydrocarbon-based carboxylic acid, a hydrocarbon-based amide, a low
molecular weight hydrocarbon wax, a low molecular weight
polyolefin, a co-polymer of a low molecular weight polyolefin, a
hydrocarbon-based polyol, a derivative of a hydrocarbon-based
polyol, an alkanolamine, a derivative of an alkanolamine, an
organic dispersing agent, or a mixture thereof. It is more
preferred that the organic material is an organo-silane having the
formula: R.sup.5.sub.xSiR.sup.6.sub.4-x wherein R.sup.5 is a
nonhydrolyzable alkyl, cycloalkyl, aryl, or aralkyl group having at
least 1 to about 20 carbon atoms; R.sup.6 is a hydrolyzable alkoxy,
halogen, acetoxy, or hydroxy group; and x=1 to 3. It is most
preferred that the organic material is Octyltriethoxysilane. In a
further aspect of the invention the metal oxide is alumina and the
organic material is octyltriethoxysilane.
[0040] In an aspect of the invention the monolayer container and/or
monolayer closure can have a concentration of TiO.sub.2 particles
of from above 0 wt % to about 8 wt % of the monolayer, preferably
0.5 to 8 wt % of the monolayer, more preferably 0.5 to 4 wt % of
the monolayer. In another aspect of the invention, the monolayer
container and the monolayer closure can be comprised of different
materials or different levels of the same or different materials.
The melt processable resin(s) can be selected from the group of
polyolefins. In an aspect of the invention the melt processable
resin is preferably a high-density polyethylene and the monolayer
container has a thickness of 8 mil to 50 mil, or more preferably 10
mil to 35 mil.
[0041] TiO.sub.2 particles may be in the rutile or anatase
crystalline form. It is commonly made by either a chloride process
or a sulfate process. In the chloride process, TiCl.sub.4 is
oxidized to TiO.sub.2 particles. In the sulfate process, sulfuric
acid and ore containing titanium are dissolved, and the resulting
solution goes through a series of precipitation steps to yield
TiO.sub.2. Both the sulfate and chloride processes are described in
greater detail in "The Pigment Handbook", Vol. 1, 2nd Ed., John
Wiley & Sons, NY (1988), the teachings of which are
incorporated herein by reference.
[0042] TiO.sub.2 particles may have a medium diameter range of
about 100 nm to about 250 nm as measured by X-Ray centrifuge
technique, specifically utilizing a Brookhaven Industries model
TF-3005W X-ray Centrifuge Particle Size Analyzer. The crystal phase
of the TiO.sub.2 is preferably rutile. The TiO.sub.2 after
receiving surface treatments can have a mean size distribution in
diameter of about 100 nm to about 400 nm, more preferably about 100
nm to about 250 nm. Nanoparticles (those have mean size
distribution less than about 100 nm in their diameter) could also
be used in this invention but may provide different light
protection performance properties.
[0043] The TiO.sub.2 particles may be substantially pure, such as
containing only titanium dioxide, or may be treated with other
metal oxides, such as silica, alumina, and/or zirconia. TiO.sub.2
particles coated/treated with alumina are preferred in the present
invention. The TiO.sub.2 particles may be treated with metal
oxides, for example, by co-oxidizing or co-precipitating inorganic
compounds with metal compounds. If a TiO.sub.2 particle is
co-oxidized or co-precipitated, then up to about 20 wt % of the
other metal oxide, more typically, 0.5 to 5 wt %, most typically
about 0.5 to about 1.5 wt % may be present, based on the total
particle weight.
[0044] The treated titanium dioxide can be formed, for example, by
the process comprising: (a) providing titanium dioxide particles
having on the surface of said particles a substantially
encapsulating layer comprising a pyrogenically-deposited metal
oxide or precipitated inorganic oxides; (b) treating the particles
with at least one organic surface treatment material selected from
an organo-silane, an organo-siloxane, a fluoro-silane, an
organo-phosphonate, an organo-acid phosphate, an
organo-pyrophosphate, an organo-polyphosphate, an
organo-metaphosphate, an organo-phosphinate, an organo-sulfonic
compound, a hydrocarbon-based carboxylic acid, an associated ester
of a hydrocarbon-based carboxylic acid, a derivative of a
hydrocarbon-based carboxylic acid, a hydrocarbon-based amide, a low
molecular weight hydrocarbon wax, a low molecular weight
polyolefin, a co-polymer of a low molecular weight polyolefin, a
hydrocarbon-based polyol, a derivative of a hydrocarbon-based
polyol, an alkanolamine, a derivative of an alkanolamine, an
organic dispersing agent, or a mixture thereof; and (c) optionally,
repeating step (b).
[0045] An example of a method of treating or coating TiO.sub.2
particles with amorphous alumina is taught in Example 1 of U.S.
Pat. No. 4,460,655 incorporated herein by reference. In this
process, fluoride ion, typically present at levels that range from
about 0.05 wt % to 2 wt % (total particle basis), is used to
disrupt the crystallinity of the alumina, typically present at
levels that range from about 1 wt % to about 8 wt % (total particle
basis), as the latter is being deposited onto the titanium dioxide
particles. Note that other ions that possess an affinity for
alumina such as, for example, citrate, phosphate or sulfate can be
substituted in comparable amounts, either individually or in
combination, for the fluoride ion in this process. The performance
properties of white pigments comprising TiO.sub.2 particles coated
with alumina or alumina-silica having fluoride compound or fluoride
ions associated with them are enhanced when the coated TiO.sub.2 is
treated with an organosilicon compound. The resulting compositions
are particularly useful in plastics applications. Further methods
of treating or coating particles of the present invention are
disclosed, for example, in U.S. Pat. No. 5,562,990 and US
2005/0239921, the subject matter of which is herein incorporated by
reference.
[0046] Titanium dioxide particles may be treated with an organic
compound such as low molecular weight polyols, organosiloxanes,
organosilanes, alkylcarboxylic acids, alkylsulfonates,
organophosphates, organophosphonates and mixtures thereof. The
preferred organic compound is selected from the group consisting of
low molecular weight polyols, organosiloxanes, organosilanes and
organophosphonates and mixtures thereof and the organic compound is
present at a loading of between 0.2 wt % and 2 wt %, 0.3 wt % and 1
wt %, or 0.7 wt % and 1.3 wt % on a total particle basis. The
organic compound can be in the range of about 0.1 to about 25 wt %,
or 0.1 to about 10 wt %, or about 0.3 to about 5 wt %, or about 0.7
to about 2 wt %. One of the preferred organic compounds used in the
present invention is polydimethyl siloxane; other preferred organic
compounds used in the present invention include carboxylic acid
containing material, a polyalcohol, an amide, an amine, a silicon
compound, another metal oxide, or combinations of two or more
thereof.
[0047] In a preferred embodiment, the at least one organic surface
treatment material is an organo-silane having the formula:
R.sup.5.sub.xSiR.sup.6.sub.4-x wherein R.sup.5 is a nonhydrolyzable
alkyl, cycloalkyl, aryl, or aralkyl group having at least 1 to
about 20 carbon atoms; R.sup.6 is a hydrolyzable alkoxy, halogen,
acetoxy, or hydroxy group; and x=1 to 3. Octyltriethoxysilane is a
preferred organo-silane.
[0048] The following TiO.sub.2 pigments may be useful TiO.sub.2
particles in the present invention: Chemours Ti-Pure.TM. R-101,
R-104, R-105, R-108, R-350, TS-1600, and TS-1601. Other TiO.sub.2
grades with similar size and surface treatments may also be useful
in the invention.
[0049] When the TiO.sub.2 particles and color pigments are used in
a polymer composition/melt, the melt-processable polymer that can
be employed together with the TiO.sub.2 particles and color
pigments comprise a high molecular weight polymer, preferably
thermoplastic resin. By "high molecular weight" it is meant to
describe polymers having a melt index value of 0.01 to 50,
typically from 2 to 10 as measured by ASTM method D1238-98. By
"melt-processable," it is meant a polymer must be melted (or be in
a molten state) before it can be extruded or otherwise converted
into shaped articles, including films and objects having from one
to three dimensions. Also, it is meant that a polymer can be
repeatedly manipulated in a processing step that involves obtaining
the polymer in the molten state.
[0050] Polymers that are suitable for use in this invention
include, by way of example but not limited thereto, polymers of
ethylenically unsaturated monomers including olefins such as
polyethylene, polypropylene, polybutylene, and copolymers of
ethylene with higher olefins such as alpha olefins containing 4 to
10 carbon atoms or vinyl acetate; vinyls such as polyvinyl
chloride, polyvinyl esters such as polyvinyl acetate, polystyrene,
acrylic homopolymers and copolymers; phenolics; alkyds; amino
resins; polyamides; phenoxy resins, polysulfones; polycarbonates;
polyesters and chlorinated polyesters; polyethers; acetal resins;
polyimides; and polyoxyethylenes. Mixtures of polymers are also
contemplated. Polymers suitable for use in the present invention
also include various rubbers and/or elastomers, either natural or
synthetic polymers based on copolymerization, grafting, or physical
blending of various diene monomers with the above-mentioned
polymers, all as generally known in the art. Typically, the polymer
may be selected from the group consisting of polyolefin, polyvinyl
chloride, polyamide and polyester, and mixture of these. More
typically used polymers are polyolefins. Most typically used
polymers are polyolefins selected from the group consisting of
polyethylene, polypropylene, and mixture thereof. A typical
polyethylene polymer is low density polyethylene (LDPE), linear low
density polyethylene (LLDPE), and high density polyethylene (HDPE).
Additional polymers include, for example, polyethylene
Terephthalate (PET, PETE), polypropylene (PP), polystyrene (PS),
and polyvinyl chloride (PVC, vinyl).
[0051] A wide variety of additives may be present in the package of
this invention as necessary, desirable, or conventional. Such
additives include polymer processing aids such as fluoropolymers,
fluoroelastomers, etc., catalysts, initiators, antioxidants (e.g.,
hindered phenol such as butylated hydroxytoluene), blowing agent,
ultraviolet light stabilizers (e.g., hindered amine light
stabilizers or "HALS"), organic pigments including tinctorial
pigments, plasticizers, antiblocking agents (e.g. clay, talc,
calcium carbonate, silica, silicone oil, and the like) leveling
agents, flame retardants, anti-cratering additives, and the like.
Additional additives further include plasticizers, optical
brighteners, adhesion promoters, stabilizers (e.g., hydrolytic
stabilizers, radiation stabilizers, thermal stabilizers, and
ultraviolet (UV) light stabilizers), antioxidants, ultraviolet ray
absorbers, anti-static agents, colorants, dyes or pigments,
delustrants, fillers, fire-retardants, lubricants, reinforcing
agents (e.g., glass fiber and flakes), processing aids, anti-slip
agents, slip agents (e.g., talc, anti-block agents), and other
additives.
[0052] Any melt compounding techniques known to those skilled in
the art may be used to process the compositions of the present
invention. Packages of the present invention may be made after the
formation of a masterbatch. The term masterbatch is used herein to
describe a mixture of TiO.sub.2 particles and color pigments
(collectively called solids) which can be melt processed at high
solids to resin loadings (generally 50-80 wt % by weight of the
total masterbatch) in high shear compounding machinery such as
Banbury mixers, continuous mixers or twin screw mixers, which are
capable of providing enough shear to fully incorporate and disperse
the solids into the melt processable resin. The resultant melt
processable resin product is commonly known as a masterbatch, and
is typically subsequently diluted or "letdown" by incorporation of
additional virgin melt processable resin in plastic production
processes. The letdown procedure is accomplished in the desired
processing machinery utilized to make the final consumer article,
whether it is sheet, film, bottle, package or another shape. The
amount of virgin resin utilized and the final solids content is
determined by the use specifications of the final consumer article.
The masterbatch composition of this invention is useful in the
production of shaped articles.
[0053] In another embodiment of the present invention, the titanium
dioxide and color pigment are supplied for processing into the
package as a masterbatch concentrate. Preferred masterbatch
concentrates typically have titanium dioxide content of greater
than 40 wt %, greater than 50 wt %, greater than 60 wt %, greater
than 70 wt %, or greater than 80 wt %. Preferred color concentrate
masterbatches are solid. Liquid color concentrates and/or a
combination of liquid and solid color concentrates could be
used.
[0054] In an aspect of the invention, the amount of titanium
dioxide particles in the package of the invention can be any
suitable amount which results in the desired LPF value. For
example, the amount of titanium dioxide particles contained in the
container and/or closure can be at least about 0.5 wt %, and
preferably at least about 0.1 wt %. In an aspect of the invention
the titanium dioxide particles in the container and/or closure can
be from about 0.5 wt % to about 20 wt %, and is preferably from
about 0.1 wt % to about 15 wt %, more preferably 5 wt % to 10 wt %.
In a further aspect of the invention the titanium dioxide particles
in the container and/or closure can be from at least about 0.5 wt
%, 0.6 wt %, 0.7 wt %, 0.8 wt %, 0.9 wt %, 1 wt %, 2 wt %, 3 wt %,
4 wt %, 5 wt %, 6 wt %, 7 wt %, 8 wt %, 9 wt %, 10 wt %, 11 wt % to
12 wt %. In an aspect of the invention the titanium dioxide
particles in the container and/or closure can be any amount between
0.1 wt % and 12 wt % (all wt % are based on the total weight of the
monolayer of the container and/or closure).
[0055] A package is typically produced by melt blending the
masterbatch containing the titanium dioxide and color pigment with
a second high molecular weight melt-processable polymer to produce
the desired composition used to form the finished monolayer
package. The masterbatch composition and second high molecular
weight polymer can be melt blended, using any means known in the
art, as disclosed above in desired ratios to produce the desired
composition of the final monolayer package. In this process,
twin-screw extruders are commonly used. The resultant melt blended
polymer is extruded or otherwise processed to form a package,
sheet, or other shaped article of the desired composition. The melt
blended polymer may be injection into a preform for subsequent
stretch blow molding processing.
[0056] The package may have one or more additional functional layer
or layers. Such layer or layers may be formed from a label, paper,
printed ink, wrap, coating treatment or other material. The layer
or layers may cover part or all of the surface of the package. The
functional layer or layers may be on the internal walls of the
package. The functional layer or layers may contribute some light
protection performance to the package, but the primary light
protection monolayer provides substantially more light protection
than the light protection provided by the functional layer or
layers.
[0057] Layers applied for aesthetic purposes, including for
branding and product information like nutrition and ingredient
labels, may not be complete layers. For example, labels may only
cover a small area on the surface area of a package or a wrap may
cover the sides of a package, but not the base. Such incomplete
layers cannot provide fully effective light protection as light can
enter the package through the surfaces of the package that are not
covered by the layer. As light can enter the package from any
direction, having complete coverage of the package is an important
consideration in the package light protection design. Hence,
aesthetic layers are often deficient in providing the primary mode
of light protection for a package design. Functional layers
typically have a narrowly defined purpose, such as providing gas
barrier properties or to prevent interactions of layers or to bind
two layers together and thus are not designed for light protection.
The present invention addresses this challenge by providing and
designing light protection directly into the primary package thus
imparting light protection to substantially all of the package
surface.
[0058] The monolayer container is provided with a removable and
re-sealable monolayer closure (e.g., cap). In an aspect of the
invention the monolayer closure can comprise substantially the same
material as the monolayer container. In a further aspect of the
invention the monolayer closure can be a different material from
the monolayer container and can also be a different color than the
monolayer container or the same color.
[0059] In an aspect of the invention, extrusion blow molding can be
used to produce the monolayer container and/or monolayer cap. In
yet another embodiment, a pre-form can be produced by injection
molding used to produce the monolayer container and/or monolayer
cap using a stretch blow molding process.
General Steps of Blow Molding
[0060] Blow molding is a molding process in which air pressure is
used to inflate soft plastic into a mold cavity. Blow molding
techniques have been disclosed in the art, for example in
"Petrothene.RTM. Polyolefins . . . a processing guide", 5th
Edition, 1986, U.S.I Chemicals. Blow molding is an important
industrial process for making one-piece hollow plastic parts with
thin walls, such as bottles and similar containers. Blow molding is
accomplished in two stages: (1) fabrication of a starting tube of
molten plastic, called a parison, or an injection molded preform
that is properly heated to a molten state; and (2) inflation of the
tube or preform in a mold to the desired final shape. Forming the
parison or preform is accomplished by either of two processes:
extrusion or injection molding.
[0061] Extrusion blow molding contains four steps: (1) extrusion of
parison; (2) parison is pinched at the top and sealed at the bottom
around a metal blow pin as the two halves of the mold come
together; (3) the tube is inflated so that it takes the shape of
the mold cavity; and (4) mold is opened to remove the solidified
part.
[0062] Injection blow molding contains the same steps as blow
molding; however, is the injection molded preform is used rather
than an extruded parison: (1) preform is injection molded; (2)
injection mold is opened and preform is transferred to a blow mold;
(3) preform is heated to become molten and inflated to conform to a
blow mold; and (4) blow mold is opened and blown product is
removed.
[0063] Blow molding is limited to thermoplastics. Polyethylene is
the polymer most commonly used for blow molding; in particular,
high density and high molecular weight polyethylene (HDPE and
HMWPE). In comparing their properties with those of low density PE
given the requirement for stiffness in the final product, it is
more economical to use these more expensive materials because the
container walls can be made thinner. Other blow moldings are made
of polypropylene (PP), polyvinylchloride (PVC), and polyethylene
terephthalate (PET).
[0064] The package finds utility to contain dairy and non-dairy
milk products, usually liquids. Liquid should be understood to mean
a liquid that is taken or derived from a protein source, such as
coconut, soybean, cows, goats, etc. Non-dairy milk includes, for
example, liquid derived from almonds, cashews, coconuts, flax, soy,
rice, hazelnut, hemp, quino, etc.
[0065] Measuring Light Protection Performance or LPF
[0066] The LPF value quantifies the protection a packaging material
can provide for a light sensitive entity in a product when the
packaged product is exposed to light. The LPF value for a packaging
material is quantified in our experiment as the time when half of
the product light sensitive entity concentration has been degraded
or otherwise undergone transformation in the controlled
experimental light exposure conditions. Hence, a product comprising
one or more light sensitive entities protected by a high LPF value
package can be exposed to a larger dose of light before changes
will occur to the light sensitive entity versus the product
protected by a low LPF value package.
[0067] A detailed description of measuring LPF value is further
described in commonly owned U.S. Pat. No. 9,638,679 titled,
"Methods for Determining Photo Protective Materials" and U.S. Pat.
No. 9,372,145 titled, "Devices for Determining Photo Protective
Materials incorporated herein by reference. Additional information
may be found in the Examples herein. The LPF values reported in the
Examples that follow were measured according to the teachings of
the above patent applications.
[0068] The current invention is focused on identifying new packages
with light protective properties that protect species from photo
chemical process (e.g., photo oxidation). Photochemical processes
alter entities such as riboflavin, curcurim, myoglobin, chlorophyll
(all forms), vitamin A, and erythrosine under the right conditions.
Other photosensitive entities that may be used in the present
invention include those found in foods, cosmetics, pharmaceuticals,
biological materials such as proteins, enzymes, and chemical
materials. In the present invention, LPF protection is reported for
the light sensitive entity riboflavin. Riboflavin is the preferred
entity to track performance for dairy applications although other
light sensitive entities may also be protected from the effects of
light.
EXAMPLES
Treated TiO.sub.2
[0069] Treated TiO.sub.2 particles comprising an inorganic surface
modification using alumina hydrous oxide, fluoride ions and
organosilicon compound were prepared substantially according to the
teachings of U.S. Pat. No. 5,562,990.
Production of Plaque Samples for LPF Evaluation
[0070] Low density polyethylene (LDPE) (DuPont 20, DuPont,
Wilmington, Del.) and TiO.sub.2 and color pigment masterbatch
concentrate pellets were pre-weighed in amounts to yield the final
ratios desired in batches of 190 g. Concentrate and resin mixtures
were compounded on a two-roll mill (Stewart Bolling & Co.,
Cleveland, Ohio) at 220-240.degree. F. with a gap of 0.035 in. The
initial melt was performed with rollers stationary, and roller
speed was slowly increased from 10 ft/min to final speeds of 45 and
35 ft/min for front and back rollers, respectively. Material was
cut off the rollers, folded, and re-applied a total of 10 times to
ensure complete mixing. The material was removed from the rollers
for the final time as a single sheet and this stock was immediately
cut into smaller pieces to better fit the compression mold.
Compression molding of rigid plaques from this material was
performed using two hydraulic presses (Carver, Wabash, Ind.) in
sequence, the first heated to 350.degree. F. to melt and mold the
material and the second water-cooled to freeze the plaque shape.
Compounded LDPE material was placed between Mylar sheets over a
mold between platens, held for 2 min at a pressure of 25 tons in
the hot press, and then for 2 min at 12.5 tons in the cold press.
The Mylar was removed and excess plastic around each plaque was
trimmed, yielding rectangular plaques about 5 cm by 10 cm with
average thickness of approximately 30 mil. This procedure was
repeated at different levels of masterbatch concentrates to produce
the desired series of samples with varied composition.
Example 1
[0071] As disclosed in commonly owned WO2016/196529, the light
protection performance of a packaging material can be quantified
with a light protection factor ("LPF") value. Further, as disclosed
in commonly owned U.S. Pat. No. 9,638,679, sample holders can be
selected to hold different types of packaging samples.
[0072] The cap LPF measurements employed a specialized cap holder
to study these smaller packaging parts, as shown in FIG. 7B. As
this specialized cap holder yields a smaller light exposed area,
the resultant LPF numbers are not directly comparable to LPF
numbers using the standard holder, as shown in FIG. 7A, presented
in the examples of U.S. Pat. No. 9,638,679. These LPF numbers using
the cap holder are denoted LPFc.
[0073] To renormalize the LPFc numbers to the same scale as the
standard square LPF evaluation sample holder used for the remaining
evaluations of the bottle and wrap samples, a series of packages
were evaluated in both sample holders to build a correlation
between the LPF and LPFc data. This correlation was used to
renormalize the measured LPFc numbers to the standard LPF scale.
The resultant data from these experiments is captured in Table 1
and represents the average of at least two replicate
evaluations.
TABLE-US-00001 TABLE 1 Sample ID LPF LPFc Blank (no sample) 0.18
0.29 Opacity 3 Film (2% R-104) 1.69 2.83 MA-1-01-V-62 smooth 7.40
10.50 MA-1-04-V-62 smooth 30.11 40.03
[0074] A linear regression was performed on the data in Table 1 to
a simple y=m.times.model with LPFc as y, LPF as x, and m as the
fitted slope. An excellent correlation was observed with a
correlation coefficient (R.sup.2) value of 0.9993 and a slope of
1.3355 is shown in FIG. 6.
Example 2
[0075] A series of liquid dairy food products in plastic packages
were purchased from retail food stores. These food products
selected as packages of interest as they were in packages with
light protection features. These packages consisted of monolayer
plastic bottles with additional layers in some samples including
labels or wraps covering portions of the bottle surface, with
plastic closures or caps. In this series of products, there were no
additional layers under the cap (e.g., foils or seals). The
packages are described below. [0076] Package 140: Dairy Pure Milk
(distributed by Dean Foods) 1/2 gallon HDPE package that is white
in appearance with green LDPE cap. [0077] Package 141: Fairlife
(distributed by Coca Cola), 1/2 gallon PET package that is white in
appearance with printed wrap and white HDPE cap. [0078] Package
142: Boost (distributed by Nestle), 8 oz. PET package that is
natural resin in appearance with printed wrap and red cap with a
white insert under the cap top portion.
[0079] Applying the teachings of WO2016/196529, U.S. Pat. No.
9,372,145, and U.S. Pat. No. 9,63,679 and Example 1, this series of
package samples was evaluated for their LPF values, or light
protection performances, by measuring the performances of the
individual package components including the bottle, the bottle plus
wrap composite (where applicable), and cap. The bottle and bottle
with wrap composite were measured for LPF as taught in the examples
of U.S. Pat. No. 9,63,679. The caps were evaluated using the
methods of the examples of U.S. Pat. No. 9,63,679 but also the cap
holder described in Example 1 to yield the LPFc values and the data
was normalized using the equation of Example 1 and reported on an
LPF basis. All LPF data is reported in Table 2.
TABLE-US-00002 TABLE 2 LPF Sample ID Bottle Bottle with wrap Cap
140 11.9 NA 3.1 141 150.4 >>100 9.1 142 <1 >100
>100
[0080] For a light protection package design of the claimed
invention, an LPF of greater than 20 is needed for all the package
components. As can be seen in the data table, the LPF value of
packages varies substantially across the components.
[0081] Package 140 has components that are all less than LPF 12 and
thus would not be suitable for the application.
[0082] Package 141 has a wrap that is LPF of greater than 100 and a
bottle that is LPF150, but the LPF of the cap is only LPF 12 and
thus the design is not of sufficient light protection performance
due to the deficiencies of the cap.
[0083] Package 142 has a bottle with low light protection of LPF
less than 1. The wrap offers improved performance but is not
complete and leaves bottle areas exposed to light. The cap provides
a high light protection performance with an LPF of greater than
100; however, this cap is not a monolayer as it has an insert under
the top portion.
[0084] Through these examples we do not find a monolayer design of
a bottle plus cap that is able to provide sufficient light
protection of LPF 20 or greater. Further we did not find suitable
design elements that could be combined across these packages to
provide the solution claimed in the invention of the
application.
Example 3
[0085] A plastic package including a bottle and closure of the
claimed invention were designed to contain liquid dairy product.
The plastic package components including a bottle and cap were
produced and evaluated using the methods of Example 1 and 2. This
package consisted of a monolayer plastic bottle comprising
polyethylene terephthalate (PETE or PET) with Ti-Pure.TM. TS-1601
Treated Titanium Dioxide and a monolayer plastic cap comprising
high density polyethylene (HDPE) with Ti-Pure.TM. TS-1600 Treated
Titanium Dioxide.
[0086] These packaging components were produced using standard
package production processes known to those that are skilled in the
art. The bottle was produced by injection stretch blow molding and
the Ti-Pure.TM. titanium dioxide was added to the injection molding
process as a masterbatch along with natural resin to produce the
preform. The preform was then used to produce the bottle by stretch
blow molding. The cap was produced by injection molding and the
Ti-Pure.TM. titanium dioxide was added to the injection molding
process as a masterbatch and added with natural resin.
[0087] The stretch blow molding process yielded a bottle with a
wall thickness of 24.5 mil and a TS-1601 composition of 7.0 wt %.
The cap was produced to a top portion thickness of 31.8 mil and a
TS-1600 composition of 3.8 wt %. There were no additional layers
under the cap (e.g., foils or seals). The bottle and cap were
evaluated for their LPF performances. The LPF performance of the
bottle was greater than LPF 100. The LPF performance on the cap was
LPF 46.
[0088] The performance objective was to create a package with LPF
above 40 and as both the bottle and cap tested higher for LPF than
this threshold, the design criteria were achieved.
Comparative Example 1
[0089] This example demonstrates the ability to measure and
quantify the deficiency of current white caps on certain,
representative retail dairy beverage packages.
[0090] Using the LPF measurement method disclosed in commonly owned
U.S. Pat. No. 9,638,679, a modified sample holder (FIG. 7B) is
applied versus that presented in the examples of U.S. Pat. No.
9,638,679 (FIG. 7A). This modified holder allowed for the
assessment of the small plastic bottle caps.
[0091] FIG. 7A is a schematic illustration of the sample holder
disclosed in U.S. Pat. No. 9,638,679, while FIG. 7B is a schematic
illustration of a modified sample holder for a cap used to isolate
the light exposure to the cap top portion of the cap and then to
direct this light to the top portion in a controlled fashion. The
modified, specialized holder is useful for study of bottle caps and
closures which play an important role in the light protection
performance of a package. A light protection performance
measurement taken with this modified cap sample holder is denoted
LPFc.
[0092] Using the cap sample holder, white caps obtained from dairy
beverage packages purchased at retail were measured for cap top
portion light protection performance, LPFc. In addition, the caps
were characterized for thickness in their top portion where each
reported value represents an average of several measurements taken
over the cap top portion in areas without features (e.g., raised
symbols or codes impressed into the cap). The results are provided
in Table 4, below.
TABLE-US-00003 TABLE 4 Part Description Thickness (mil) LPF.sub.c
White cap from Fairlife Power Shot 45.2 12.7 White cap from Mueller
29.5 11.4 Fruchtbuttermilch White cap from Oberweis Milk 29.3
3.7
[0093] The measured light protection factor of the caps is all
below LPFc15, indicating a low light protection performance. Light
protection performances of LPFc50 or higher are desired for this
application to ensure preservation of the nutrient content in the
packaged product. The top portion thicknesses of the caps are all
below 46 mil. All of the caps evaluated were below the LPFc50
target indicating that light protection is insufficient and that
light can enter the package through the cap top portion and cause
detrimental effects to the nutrients and sensory quality (e.g.,
color, odor, flavor) of the packaged product.
Example 5
[0094] This example illustrates how increasing the top portion
thickness can result in increasing the cap LPFc and achieve the
desire light protection performance in this part of a package
design.
[0095] LPFc was measured as described in Comparative Example 1 on a
set of white parts prepared to simulate a cap top portion. This set
of samples demonstrates the impact on light protection performance
of increasing top portion thickness on a cap. The white parts were
produced by injection molding, the same processing typically used
for cap production. The parts were composed of polyethylene and
surface treated Ti-Pure.TM. TiO.sub.2 (TS-1600, available from the
Chemours Company, Wilmington, Del.) at a loading of 1 wt % added to
the cap using a 50 wt % Ti-Pure.TM. TS-1600 TiO.sub.2 masterbatch.
It is noted that this level of TiO.sub.2 can be utilized in
injection molding processes by one skilled in the art without
difficulty. For this design an LPFc of greater than 100 was
desired. The results of the measurements are provided in Table
5.
TABLE-US-00004 TABLE 5 Part Description Thickness (mil) LPF.sub.c
White step 1 34.7 24.9 White step 2 55.8 40.3 White step 3 105.1
107.0
[0096] These data demonstrate that for a fixed composition of
Ti-Pure.TM. TiO.sub.2 in polyethylene, by increasing the thickness
of the material by about 3 times, the light protection performance
is increased about 4.3 times. Thus, for a cap prepared with this
same composition, increased light protection can be obtained with a
thicker top cap portion.
[0097] For the design objective of achieving a LPFc of greater than
50, the thickness of the white step 3 sample provides the desired
light protection performance. Further, the data in Table 5 can be
modeled with an exponential function and with the model it is
predicted that LPFc of 50 can be achieved with a thickness of 67.6
mil with this same composition.
* * * * *