U.S. patent application number 15/278511 was filed with the patent office on 2017-01-19 for soda-lime glass from 100% recycled glass-forming materials.
The applicant listed for this patent is Owens-Brockway Glass Container Inc.. Invention is credited to Robert Brouwer.
Application Number | 20170015582 15/278511 |
Document ID | / |
Family ID | 51799346 |
Filed Date | 2017-01-19 |
United States Patent
Application |
20170015582 |
Kind Code |
A1 |
Brouwer; Robert |
January 19, 2017 |
Soda-Lime Glass from 100% Recycled Glass-Forming Materials
Abstract
A glass food and beverage container constructed of 100 wt. %
recycled glass-forming materials selected from the group consisting
of post-industrial cullet, post-consumer cullet, and a combination
thereof.
Inventors: |
Brouwer; Robert; (Berkel en
Rodenrijs, NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Owens-Brockway Glass Container Inc. |
Perrysburg |
OH |
US |
|
|
Family ID: |
51799346 |
Appl. No.: |
15/278511 |
Filed: |
September 28, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14089066 |
Nov 25, 2013 |
9475724 |
|
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15278511 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02W 30/80 20150501;
Y10T 428/131 20150115; C03C 3/04 20130101; C03B 25/00 20130101;
C03C 1/002 20130101; C03C 4/02 20130101; C03C 3/087 20130101; C03C
2204/00 20130101; B65D 1/0207 20130101; Y02W 30/803 20150501; C03B
9/00 20130101; B65D 1/0223 20130101; B65D 1/023 20130101; B65D
2565/384 20130101 |
International
Class: |
C03C 3/087 20060101
C03C003/087; B65D 1/02 20060101 B65D001/02 |
Claims
1. A glass food and beverage container constructed of 100 wt. %
recycled glass-forming materials selected from the group consisting
of post-industrial cullet, post-consumer cullet, and a combination
thereof.
2. The container set forth in claim 1 wherein the glass-forming
materials include substantially no virgin raw materials.
3. A glass container comprising: a soda-lime glass wall that
provides the container with a body, a circumferentially-closed base
at one end of the body, and a mouth at another end of the body
opposite the circumferentially-closed base, the soda-lime glass
wall having a glass composition that includes a main oxide content
of about 60-75 wt. % SiO.sub.2, about 10-18 wt. % Na.sub.2O, and
about 5-15 wt. % CaO, and wherein the main oxide content of the
glass composition of the soda-lime glass wall is derived only from
cullet.
4. The glass container set forth in claim 3, wherein the main oxide
content of the glass composition of the soda-lime glass wall is
derived from pre-sorted cullet that comprises 40-50 wt. % green
glass, 40-50 wt. % flint glass, 5-15 wt. % amber glass, 0-2 wt. %
blue glass and other colored glass, and less than 250 grams/ton of
opal glass 40-50 wt. % green glass.
5. A glass container comprising: a soda-lime glass wall that
provides the container with a body, a circumferentially-closed base
at one end of the body, and a mouth at another end of the body
opposite the circumferentially-closed base, the soda-lime glass
wall having a glass composition that includes a main oxide content
of about 60-75 wt. % SiO.sub.2, about 10-18 wt. % Na.sub.2O, and
about 5-15 wt. % CaO, and wherein the main oxide content of the
glass composition of the soda-lime glass wall is derived only from
cullet.
6. The glass container set forth in claim 5, wherein the main oxide
content of the glass composition of the soda-lime glass wall is
derived from pre-sorted cullet that comprises 40-50 wt. % green
glass, 40-50 wt. % flint glass, 5-15 wt. % amber glass, 0-2 wt. %
blue glass and other colored glass, and less than 250 grams/ton of
opal glass 40-50 wt. % green glass.
Description
[0001] The present disclosure relates to a process for making
soda-lime glass. The disclosed process uses recycled glass as the
glass-forming materials. Soda-lime glass containers made by the
disclosed process are also described.
BACKGROUND AND SUMMARY OF THE DISCLOSURE
[0002] Soda-lime glass, also called soda-lime-silica glass, is
prevalent in the manufacture of glass containers and other
articles. Such glass is comprised of three main oxide constituents:
silica (SiO.sub.2), soda (Na.sub.2O), and lime (CaO) that are
provided by the glass forming materials. Other oxides may also be
present in smaller amounts. These additional oxides may include one
or more of alumina (Al.sub.2O.sub.3), magnesia (MgO), potash
(K.sub.2O), iron oxide (Fe.sub.2O.sub.3), titanium oxide
(TiO.sub.2), sulfur trioxide (SO.sub.3), and oxides of selenium,
cobalt, chromium, manganese, and lead. A typical soda-lime glass
composition may include, for example, about 60 wt. % to about 75
wt. % silica, about 10 wt. % to about 18 wt. % soda, about 5 wt. %
to about 15 wt. % lime, and optionally about 0-2 wt. % alumina
(Al.sub.2O.sub.3), about 0-4 wt. % magnesia (MgO), about 0-1.5 wt.
% potash (K.sub.2O), about 0-1 wt. % iron oxide (Fe.sub.2O.sub.3),
about 0-0.5 wt. % titanium oxide (TiO.sub.2), and about 0-0.5 wt. %
sulfur trioxide (SO.sub.3).
[0003] Soda-lime glass may be made by melting a batch of primary or
glass-forming materials, and optional secondary or additive
materials, and then cooling the resultant melt. The glass-forming
materials are the materials from which the soda-lime glass derives
its main oxide content--namely, the silica, soda, and lime
content--and thus its amorphous physical state. There are generally
two types of glass-formers or glass-forming materials: (1) virgin
raw materials (sand, soda ash, and limestone), and (2) recycled
glass or "cullet" as it is termed in the industry. Traditionally,
the batch of primary or glass-forming materials used to make
soda-lime glass could include some cullet--usually 10-40 wt. %, and
up to 80 wt. %--with the rest being virgin raw materials. The use
of greater amounts of cullet and lesser amounts of virgin raw
materials has proven difficult to implement for many reasons,
including limited color options, unstable melt temperatures in the
melt furnace, and difficulties in achieving a uniform mix of cullet
and virgin raw materials in the melt furnace.
[0004] If used, the secondary, additive materials provide the
soda-lime glass with more stable quality. For example, additive
materials may enable better aesthetic properties, such as color,
and/or other physical qualities, such as seed (i.e., bubble)
prevention and "redox" number adjustment. They do not include main
oxide constituent glass forming materials of the soda-lime glass.
Some notable secondary, additive materials include colorants,
decolorants, fining agents, oxidizers, and reducers. The colorants
and decolorants can be used to provide the soda-lime glass with a
variety of colors including flint (colorless), amber, green, and
blue. The fining agents can be used to prevent the incorporation of
bubbles in the soda-lime glass. These agents work by removing
insoluble gas bubbles--typically oxygen--from the soda-lime glass
melt before it cools and hardens. The oxidizers and reducers can be
used to manage the "redox number" of the soda-lime glass melt as
desired.
[0005] The present disclosure embodies a number of aspects that can
be implemented separately from or in combination with each
other.
[0006] In accordance with one aspect of the present disclosure, a
glass food and beverage container is constructed of 100 wt. %
recycled content selected from the group consisting of
post-industrial cullet, post-consumer cullet, and a combination
thereof.
[0007] In accordance with still another aspect of the present
disclosure, a glass container includes a soda-lime glass wall that
provides the container with a body, a circumferentially-closed base
at one end of the body, and a mouth at another end of the body
opposite the circumferentially-closed base. The soda-lime glass
wall has a glass composition that includes a main oxide content of
about 60-75 wt. % SiO.sub.2, about 10-18 wt. % Na.sub.2O, and about
5-15 wt. % CaO. This main oxide content of the soda-lime glass wall
glass composition is derived only from cullet.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The disclosure, together with additional objects, features,
advantages and aspects thereof, will best be understood from the
following description, the appended claims and the accompanying
drawings, in which:
[0009] FIG. 1 illustrates an illustrative embodiment of a glass
container 10 that may be produced in accordance with an
illustrative embodiment of a presently disclosed manufacturing
process; and
[0010] FIG. 2 is a flow diagram that illustrates an illustrative
process for making the glass container 10 shown in FIG. 1 as well
many other kinds of glass containers.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0011] FIG. 1 illustrates an illustrative embodiment of a soda-lime
glass container 10 (hereafter "glass container" or "container")
that may be produced by the process described below. The glass
container 10 includes a soda-lime glass wall 12 that has a glass
composition. The soda-lime glass wall 12 provides the container 10
with a longitudinal axis A, a base 10a at one axial end of the
container 10 that is closed in an axial direction, a body 10b
extending in an axial direction from the axially closed base 10a,
and a mouth 10c at another axial end of the container 10 opposite
of the base 10a. Accordingly, the soda-lime glass container 10 is
hollow. In the illustrated embodiment, the soda-lime glass wall
also provides the container 10 a neck 10d that may extend axially
from the body 10b, may be generally conical in shape, and may
terminate in the mouth 10c. The container 10, however, need not
include the neck 10d. The body 10b may terminate at the mouth 10c
such as, for instance, in a soda-lime glass jar embodiment. The
body 10b may be of any suitable shape in cross-section transverse
to the axis A as long as the body 10b is circumferentially
closed.
[0012] The glass container 10, and many others like it, may be
formed from primary, glass-forming materials, and optional
secondary, additive materials, as indicated above. The term
"cullet" is used broadly in the present disclosure to mean
previously-made glass as well as any contaminants that may be
present as a result of the prior use, storage, and/or processing of
the glass. For example, some contaminants that may be found include
dirt, residual adhesive, container content stains, etc. The
glass-forming materials do not include any of the virgin raw
minerals that have conventionally been used to make soda-lime
glass, such as sand, soda ash and limestone. The use of 100 wt. %
cullet as the glass-forming materials has several ecological
implications including lower energy consumption per manufactured
container 10, a reduction in raw mineral use as compared to
previous glass forming methods, and a reduction in greenhouse gas
emissions per manufactured container 10. In the presently disclosed
process, the glass-forming materials used constitute 100 wt. %
cullet. In other words, the primary, glass-forming materials
include cullet and substantially no virgin raw materials. As used
herein, the terminology "substantially no virgin raw materials"
does not exclude accidental carryover of some trace amounts of
virgin raw materials or some de minimus use thereof to circumvent
literal infringement.
[0013] Referring now to FIG. 2, the process 20 for making the glass
container 10 may include preparing a soda-lime glass batch (step
22), melting the soda-lime glass batch into a soda-lime glass melt
(step 24), and forming the glass wall 12 that defines the shape of
container 10 from the soda-lime glass melt (step 26). This process
20 can be used to make the glass container 10 in a wide variety of
sizes and shapes. For example, the process can be used to make
beverage bottles--including beer and liquor bottles--as well as
jars and other glass containers that are designed to hold some
content in their interiors.
[0014] The soda-lime glass batch may be prepared (step 22) by
gathering the cullet which provides the primary, glass-forming
materials and, optionally, adding secondary, additive materials to
the glass batch. Most of the cullet may be provided in broken glass
chunks, shards, pieces, or the like, whose largest dimension may be
approximately 70 mm to 90 mm in diameter, with the majority of the
cullet particle sizes ranging from 10 mm to 70 mm in diameter,
whereas virgin glass batch particles are typically less than 2 mm
in diameter. To provide more thorough distribution within the
batch, the additive materials may be premixed with smaller grain
size cullet and then that mixture can be added to larger cullet
upstream of the melt furnace. More specifically, some portion of
the cullet can be provided in a powdered or other small form, for
example, closer in particle size to the secondary additive
materials.
[0015] The glass-forming materials are comprised of 100 wt. %
cullet. The secondary, additive materials may include colorants,
decolorants, fining agents, oxidizers, reducers, or any other
additive that does not contribute to the main oxide content of the
soda-lime glass. If secondary, additive materials are used, the
soda-lime glass batch may be comprised of at least 98 weight
percent (wt. %)--preferably at least 99 wt. %--cullet with the
remainder being the secondary, additive materials. At least some of
the additive materials may be recycled materials. For example, at
least some carbon content may be from recycled carbon. In another
example, sodium sulfate and/or selenium may be from materials
recycled from filter dust from the glass manufacturing facility,
for example, from an electrostatic precipitator downstream of a dry
scrubber. In a further example, at least some iron or aluminum
content may be from recycled furnace slag. In such cases, the
recycled content of the glass batch may exceed 99%.
[0016] The cullet may be post-consumer or post-industrial recycled
glass. The term "post-consumer" recycled glass includes glass from
municipal or commercial recycling efforts including, for example,
glass from bottles, glassware, windows, and solar panels. The term
"post-industrial" recycled glass includes production glass such as
internal waste glass from the same glass-producing factory that is
manufacturing the glass container 10, external waste glass from
another glass-producing factory, or glass from some other
industrial setting. Most of the cullet may be provided in broken
glass chunks or shards whose largest dimension may be approximately
70 mm to 90 mm in diameter. In a preferred embodiment, at least
some of the cullet is provided as a powder.
[0017] The cullet is preferably pre-sorted, based on color, so that
a level of contaminants does not exceed a certain amount. An
embodiment of permissible pre-sorted cullet includes: 40-50 wt. %
green glass, 40-50 wt. % flint glass, 5-15 wt. % amber glass, 0-2
wt. % blue glass and other colored glass, and less than 100
grams/ton of non-soda lime container glass. Additionally, the
pre-sorted cullet of this embodiment preferably includes less than
1000 grams/ton of organics including soluble organics, like sugars,
as well as visible free organics, like pieces of plastics. More
particularly, the pre-sorted cullet preferably includes less than
500 grams/ton of visible free organics.
[0018] The color of glass cullet is generally a function of its
redox number and the presence and identity/amount of certain
compounds (oxide) in the glass, as is well understood in the art.
The redox number of a particular glass is basically a measure of
its oxidation/reduction state when in melt form. One accepted
technique for quantifying the redox number is described in Simpson
and Myers, "The Redox Number Concept and Its Use by the Glass
Technologist," Glass Technology, Vol. 19, No. 4, Aug. 4, 1978,
pages 82-85. In general, molten glass having a redox number of zero
and above is considered "oxidized," and a molten glass having a
negative redox number is considered "reduced." Table 1 below
describes some examples of prevalent glass colors that are
routinely encountered in the glass manufacturing industry,
including some specific shades thereof.
TABLE-US-00001 TABLE 1 Color affecting Redox Glass Color
Compound(s) Number GREEN Emerald Green Chromium oxide -10 to +1
Georgia Green Chromium oxide Dead Leaf Green Chromium oxide
Champagne Green Chromium oxide French Green Chromium oxide Antique
Green Chromium oxide FLINT Iron oxide, Selenium +2 to +20 AMBER
Iron, sulfur, excess -40 to -20 carbon BLUE & OTHERS Arctic
Blue Cobalt oxide +2 to +20 Cobalt Blue Cobalt oxide -20 to +10
[0019] The pre-sorted cullet provides the glass composition of the
soda-lime glass wall 12 with its main oxide content of SiO.sub.2,
Na.sub.2O, and CaO, and its amorphous physical properties. The
glass composition of the soda-lime glass wall 12 includes about
60-75 wt. % SiO.sub.2, about 10-18 wt. % Na.sub.2O, and about 5-15
wt. % CaO. Also included in the cullet may be a small amount of
other oxides or impurities, which are typical in the glass
manufacturing industry, that become incorporated into the glass
composition of the manufactured soda-lime glass wall 12. These
materials may be present in the soda-lime glass wall 12
composition, via the cullet, in amounts up to about 2.0 wt. %. Some
common additional materials that may be present include
Al.sub.2O.sub.3, MgO, K.sub.2O, Fe.sub.2O.sub.3, TiO.sub.2, BaO,
SrO, SO.sub.3, and oxides of selenium, cobalt, chromium, manganese,
and lead. Other materials besides those just mentioned may also be
present.
[0020] The secondary, additive materials, if used, are mixed with
the glass-forming materials to influence the aesthetic and other
physical qualities of the soda-lime glass wall 12. The term
"physical qualities" as used here refers to qualities of the
soda-lime glass wall 12 that can be achieved without altering the
main oxide content of its glass composition in a substantial way.
For example, certain secondary, additive materials can be added to
the soda-lime glass batch to affect the color and fining of the
manufactured soda-lime glass wall 12 without changing the main
oxide content of its glass composition. The secondary, additive
materials are preferably provided in powder form to facilitate easy
mixing with the cullet.
[0021] Colorants and decolorants are secondary, additive materials
that will affect the color of the soda-lime glass wall 12.
Colorants are compounds that produce a color in the soda-lime glass
wall 12 other than flint, and decolorants are compounds that mask
colors. Examples of suitable colorants may include, for example,
iron oxides (e.g., FeO and/or Fe.sub.2O.sub.3), chromium oxides
(e.g., CrO or Cr.sub.2O.sub.3), cobalt oxides (e.g., CoO or
Co.sub.2O.sub.3), nickel, copper, selenium, manganese, titanium,
and/or a combination of sulfur, iron, and carbon. Some of the
different colors that can be promoted by these colorants are listed
above in Table 1. Examples of suitable decolorants may include, for
example, selenium, manganese, manganese dioxide, and cerium oxide.
Selenium and manganese can both be used at low concentrations to
neutralize the green tint often present in glass as a result of
iron impurities. At higher concentrations, however, selenium and
manganese begin to promote a reddish-pink color (peach) and a
purple color, respectively.
[0022] Fining agents are secondary, additive materials that help
prevent bubble or seed formation in the soda-lime glass wall 12.
One example of a fining agent includes the combination of a metal
sulfate, such as sodium sulfate (Na.sub.2SO.sub.4), and carbon.
When present in the soda-lime glass melt, sodium sulfate and carbon
react to produce sulfur dioxide (SO.sub.2) and carbon dioxide
(CO.sub.2). Both SO.sub.2 and CO.sub.2 are gasses that are
insoluble in the glass melt. As such, these gasses rise up through
the molten soda-lime glass and encounter smaller insoluble gas
bubbles typically composed of oxygen (O.sub.2). The SO.sub.2 gas
reacts with the O.sub.2 gas to form sulfur trioxide (SO.sub.3),
which is soluble in the soda-lime glass melt, while the CO.sub.2
gas picks up the O.sub.2 gas and drags it to the surface of the
glass melt where they are released.
[0023] Oxidizers and reducers are secondary, additive materials
that would render the redox number of the soda-lime glass melt more
"oxidized" or "reduced," respectively. These additive materials can
be included in the soda-lime glass batch to modify, if desired, the
redox number of the soda-lime glass melt that would result from the
pre-sorting of the cullet. Some examples of oxidizers include
calcium sulfate (CaSO.sub.4), sodium nitrate (NaNO.sub.3), and
potassium nitrate (KNO.sub.3), while some examples of reducers
include iron pyrite (FeS.sub.2) and graphite. Some additive
materials, moreover, can function as both a fining agent and an
oxidizer/reducer. For example, sodium sulfate and carbon, which in
combination act as a fining agent, can also make the redox number
of the soda-lime glass melt more oxidized and more reduced,
respectively.
[0024] The soda-lime glass batch may be melted (step 24) in one or
more furnaces to produce the soda-lime glass melt. The temperature
of the furnace(s) is set to ensure proper melting of the glass
batch according to known practices. For example, to produce the
soda-lime glass melt, the glass batch may melted in the furnace(s)
at a temperature about 50.degree. C. lower than the temperature of
a melt of a typical glass batch (with 30-40 wt. % cullet) which is
usually between about 1400.degree. C. and about 1500.degree. C., at
a typical residence time of about two to four hours. After
achieving its melt form, the soda-lime glass melt may flow from the
furnace(s) into a refiner, where it is conditioned, and then to one
or more forehearths.
[0025] The soda-lime glass container 10 (step 26) may then be
formed from the soda-lime glass melt by a glass-blowing procedure.
A feeder located at a downstream end of the one or more
forehearths, for example, may measure and deliver a gob of the
soda-lime glass melt to a glass-forming machine. The gob may then
be formed into the soda-lime glass wall 12 at an individual section
machine by a press-and-blow process, a blow-and-blow process, or
any other suitable process. Once formed, the soda-lime glass wall
12 is initially cooled to preserve its desired shape, and then
annealed in one or more an annealing lehrs. The soda-lime glass
wall 12 may be annealed at a hot-end portion of the annealing
lehr(s) at a temperature between about 550.degree. C. and about
600.degree. C. for about 30 minutes to about 90 minutes, and then
gradually cooled at a cold-end portion to between about 65.degree.
C. and about 130.degree. C. Any of a variety of hot-end, cold-end,
antireflective, and/or glass strengthening coatings may be applied
to the exterior of the soda-lime glass wall 12 anytime after being
formed.
Example
[0026] A soda-lime glass batch was prepared that included 100 wt. %
cullet as the glass-forming materials. The cullet used was supplied
as a mixture of several different types of glass. Specifically, the
supplied cullet included the following mixture: 40-48 wt. % green
glass, 42-50 wt. % flint glass, 6-14 wt. % amber glass, and 0-2 wt.
% blue glass. The supplied cullet also included less than 250 g/ton
of opal glass, less than 1000 g/ton of organics, less than 100
g/ton of plastics, less than 25 g/ton of ceramics, less than 5
g/ton of magnetic metals, and less than 5 g/ton of non-magnetic
metals.
[0027] There thus has been disclosed a process for making soda-lime
glass that fully achieves all of the objects and aims previously
set forth. The disclosure has been presented in conjunction with
presently preferred embodiments, and alternatives and modifications
have been discussed. Other alternatives and modifications readily
will suggest themselves to persons of ordinary skill in the art in
view of the foregoing description. The disclosure is intended to
embrace all such modifications and variations as fall within the
spirit and broad scope of the appended claims.
* * * * *