U.S. patent application number 13/139810 was filed with the patent office on 2011-10-20 for moldable articles, method of making same and method of molding.
Invention is credited to Amy S. Barnes, Steven J. Lenius, Anatoly Z. Rosenflanz.
Application Number | 20110253582 13/139810 |
Document ID | / |
Family ID | 42288354 |
Filed Date | 2011-10-20 |
United States Patent
Application |
20110253582 |
Kind Code |
A1 |
Lenius; Steven J. ; et
al. |
October 20, 2011 |
MOLDABLE ARTICLES, METHOD OF MAKING SAME AND METHOD OF MOLDING
Abstract
A moldable article, including at least a container made of a
barrier material, the container providing an interior space within
which a plurality of glass particles are contained. The glass has a
glass transition temperature and a crystallization onset
temperature, the difference between the glass transition
temperature and the crystallization onset temperature is at least
about 5.degree. K., and the glass is composed of at least two metal
oxides, from 0 to less than 20% by weight SiO.sub.2, from 0 to less
than 20% by weight B.sub.2O.sub.3, and from 0 to less than 40% by
weight P.sub.2O.sub.5. The moldable article protects the glass
particles by keeping them clean and moisture free prior to a
molding operation. A method of making a moldable article includes:
removing entrapped moisture from a plurality of glass particles,
placing glass particles in a receptacle, and sealing the receptacle
to form the article. The moldable article may be placed in a mold
and, during the molding process, the barrier material essentially
burns off while the glass particles coalesce into a molded
article.
Inventors: |
Lenius; Steven J.;
(Woodbury, MN) ; Rosenflanz; Anatoly Z.;
(Maplewood, MN) ; Barnes; Amy S.; (St. Paul,
MN) |
Family ID: |
42288354 |
Appl. No.: |
13/139810 |
Filed: |
November 24, 2009 |
PCT Filed: |
November 24, 2009 |
PCT NO: |
PCT/US09/65647 |
371 Date: |
June 15, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61140333 |
Dec 23, 2008 |
|
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|
Current U.S.
Class: |
206/524.1 ;
53/440 |
Current CPC
Class: |
C03B 11/08 20130101;
C03C 2214/12 20130101; C03C 14/00 20130101; C03B 2215/79 20130101;
C03B 2215/406 20130101 |
Class at
Publication: |
206/524.1 ;
53/440 |
International
Class: |
B65D 85/00 20060101
B65D085/00; B65B 63/08 20060101 B65B063/08 |
Claims
1. A moldable article, comprising: A first container comprising a
first barrier, the first barrier comprised of a first material, and
an interior space within the first barrier; A plurality of first
glass particles contained within the interior space and comprising
a first glass, the plurality of first glass particles being
moldable at a first molding temperature, the first glass having a
first glass transition temperature and a first crystallization
onset temperature, the difference between the first glass
transition temperature and the first crystallization onset
temperature being at least about 5.degree. K., the first glass
having a composition comprising at least two metal oxides, from 0
to less than 20% by weight SiO.sub.2, from 0 to less than 20% by
weight B.sub.2O.sub.3, and from 0 to less than 40% by weight
P.sub.2O.sub.5; and Wherein, the first material has a first
decomposition temperature less than the first molding
temperature.
2. The article according to claim 1 wherein the first glass
particles comprise microparticles.
3. The article according to claim 1 wherein the first material
comprises a polymer.
4. The article according to claim 3 wherein the polymer is selected
from the group consisting of polyamide, poly methyl methacrylate,
polyisobutylene, polycarbonate, polyethylene carbonate,
polypropylene carbonate, polybutylene terephthalate,
polyetheretherketone, polyethylene, polypropylene, polyphenylene
oxide, polystyrene aromatic polyesters, and combinations of two or
more of the foregoing.
5. The article according to claim 4 wherein the polyamide is
selected from the group consisting of nylon 6, nylon 66 and
combinations thereof.
6. The article according to claim 4 wherein the polyethylene is
selected from the group consisting of low density polyethylene,
high density polyethylene, medium density polyethylene and
combinations of two or more of the foregoing.
7. The article according to claim 4 wherein the polyethylene is low
density polyethylene.
8. The article according to claim 1 wherein the first material is
flexible.
9. The article according to claim 1 wherein the first material is
rigid.
10. The article according to claim 1 wherein the first material is
paper.
11. The article according to claim 1 wherein the interior space is
substantially free of water vapor.
12. The article according to claim 1 wherein the interior space has
an atmosphere comprising an inert gas selected from the group
consisting of helium, neon, krypton, argon, xenon, nitrogen and
combinations of two or more of the foregoing.
13. The article according to claim 1 wherein the interior space is
divided into at least a first interior space and a second interior
space with the plurality of first glass particles contained within
the first interior space and a plurality of second glass particles
contained within the second interior space, the second glass
particles comprising a second glass having a composition different
than the composition of the first glass.
14. The article according to claim 13 wherein the second glass
particles comprise microparticles, the second glass having a second
glass transition temperature and a second crystallization onset
temperature, the difference between the second glass transition
temperature and the second crystallization onset temperature is at
least about 5.degree. K., the second glass comprising at least two
metal oxides, from 0 to less than 20% by weight SiO.sub.2, from 0
to less than 20% by weight B.sub.2O.sub.3, and from 0 to less than
40% by weight P.sub.2O.sub.5.
15. The article according to claim 1 further comprising: A second
container comprising a second barrier, the second barrier comprised
of a second material, and a second interior space within the second
barrier, the second container being wholly within the interior
space of the first container; A plurality of second glass particles
contained within the second interior space so that the plurality of
second glass particles and the plurality of first glass particles
are separated from one another, the plurality of second glass
particles comprising a second glass, the plurality of second glass
particles being moldable at a second molding temperature.
16. The article according to claim 15 wherein the second glass has
a second glass transition temperature and a second crystallization
onset temperature, the difference between the second glass
transition temperature and the second crystallization onset
temperature is at least about 5.degree. K, the second glass having
a composition different than the composition of the first glass and
comprising at least two metal oxides, from 0 to less than 20% by
weight SiO.sub.2, from 0 to less than 20% by weight B.sub.2O.sub.3,
and from 0 to less than 40% by weight P.sub.2O.sub.5.
17. The article according to claim 15 wherein the second material
has a second decomposition temperature less than the second molding
temperature.
18. The article according to claim 15 wherein the second material
is the same as the first material.
19. The article according to claim 1 wherein the first molding
temperature is about 300.degree. C. or greater.
20. A method of making a moldable article, the method comprising:
Placing a plurality of first glass particles in a first receptacle,
the plurality of first glass particles being moldable at a first
molding temperature, the first glass having a first glass
transition temperature and a first crystallization onset
temperature, the difference between the first glass transition
temperature and the first crystallization onset temperature being
at least about 5.degree. K., the first glass having a composition
comprising at least two metal oxides; Removing entrapped moisture
from the first glass particles; and Sealing the first receptacle to
form a first container comprising a first barrier, the first
barrier defining an interior space, the plurality of first
microparticles occupying at least a portion of the interior space,
wherein the interior space is substantially free of water, and
wherein the first barrier comprises a first material having a first
decomposition temperature lower than the first molding
temperature.
21-39. (canceled)
Description
[0001] The present invention relates to moldable articles for the
molding of glass particles, to methods of preparing the moldable
articles and to methods of molding the moldable articles.
BACKGROUND
[0002] Glass compositions have been used to provide large articles
and/or complex shapes. Such articles are often made by coalescing
particles of glass. Recently, such articles and complex shapes have
been made using microparticles of non-traditional glass
materials.
[0003] The manufacture of molded glass articles is accomplished in
a molding process in which glass particles are heated above the
glass transition temperature of the material. The melting particles
coalesce and, upon cooling, assume a solidified shape to form the
article. The molding process typically involves the application of
pressure on the melting particles to aid in shaping the molten
glass into the form dictated by the particular mold design.
[0004] In the utilization of molding techniques to make glass
articles, small glass particles (e.g., microparticles) are known to
collect moisture and/or static charge. This is especially true in
the manufacture of articles from microparticles of non-traditional
glass materials. As a result, glass particles are difficult to
handle during the molding process.
SUMMARY
[0005] The present invention addresses problems encountered in the
molding of glass materials. In one aspect, the invention provides a
moldable article, comprising: [0006] A first container comprising a
first barrier, the first barrier comprised of a first material, and
an interior space within the first barrier; [0007] A plurality of
first glass particles contained within the interior space and
comprising a first glass, the plurality of first glass particles
being moldable at a first molding temperature, the first glass
having a first glass transition temperature and a first
crystallization onset temperature, the difference between the first
glass transition temperature and the first crystallization onset
temperature being at least about 5.degree. K., the first glass
having a composition comprising at least two metal oxides, from 0
to less than 20% by weight SiO.sub.2, from 0 to less than 20% by
weight B.sub.2O.sub.3, and from 0 to less than 40% by weight
P.sub.2O.sub.5; and [0008] Wherein, the first material has a first
decomposition temperature less than the first molding
temperature.
[0009] In some embodiments, the interior space of the foregoing
article is divided into multiple spaces, including a first interior
space and a second interior space with the plurality of first glass
particles contained within the first interior space and a plurality
of second glass particles contained within the second interior
space, the second glass particles comprising a second glass having
a composition different than the composition of the first
glass.
[0010] In other embodiments, the moldable article further
comprises: [0011] A second container comprising a second barrier,
the second barrier comprised of a second material, and a second
interior space within the second barrier, the second container
being wholly within the interior space of the first container; and
[0012] A plurality of second glass particles contained within the
second interior space so that the plurality of second glass
particles and the plurality of first glass particles are separated
from one another, the plurality of second glass particles
comprising a second glass, the plurality of second glass particles
being moldable at a second molding temperature.
[0013] In another aspect, the invention provides a method of making
a moldable article, the method comprising: [0014] Placing a
plurality of first glass particles in a first receptacle, the
plurality of first glass particles being moldable at a first
molding temperature, the first glass having a first glass
transition temperature and a first crystallization onset
temperature, the difference between the first glass transition
temperature and the first crystallization onset temperature being
at least about 5.degree. K., the first glass having a composition
comprising at least two metal oxides; [0015] Removing entrapped
moisture from the first glass particles; and [0016] Sealing the
first receptacle to form a first container comprising a first
barrier, the first barrier defining an interior space, the
plurality of first microparticles occupying at least a portion of
the interior space, wherein the interior space is substantially
free of water, and wherein the first barrier comprises a first
material having a first decomposition temperature lower than the
first molding temperature.
[0017] In some embodiments of the foregoing method, the method
further comprises: [0018] Placing a plurality of second glass
particles in a second receptacle, the plurality of second glass
particles comprising a second glass that is moldable at a second
molding temperature; [0019] Removing entrapped moisture from the
second glass particles; and [0020] Sealing the second receptacle to
form a second container comprising a second barrier, the second
barrier defining a second interior space, the plurality of second
glass particles occupying at least a portion of the second interior
space, wherein the second barrier comprises a second material
having a second decomposition temperature lower than the second
molding temperature; and [0021] Placing the second container within
the first receptacle prior to the step of sealing the first
receptacle.
[0022] In still other embodiments of the foregoing method, the
first receptacle comprises a plurality of chambers, and the step of
placing the plurality of first glass particles in the first
receptacle comprises placing the particles in a first chamber; the
method further comprising placing a second plurality of glass
particles in a second chamber, wherein the step of sealing the
first receptacle forms the first container so that the interior
space forms a plurality of sealed chambers with the first plurality
of glass particles sealed within a first interior space and the
second plurality of glass particles sealed within a second interior
space.
[0023] In still another aspect, the invention provides a method for
molding an article, comprising: [0024] Placing one or more of the
foregoing moldable articles in a mold cavity; and [0025] Heating
the mold cavity to decompose the first material and coalesce the
glass particles to provide a molded article.
[0026] In general, terms used in the description of the embodiments
of the present invention shall be understood as having the common
meaning given to them, as understood by the person of ordinary
skill in the art. However, certain terms shall have the meaning set
forth herein.
[0027] "Amorphous material" refers to material derived from a melt
and/or a vapor phase that lacks any long range crystal structure as
determined by X-ray diffraction and/or has an exothermic peak
corresponding to the crystallization of the amorphous material as
determined by a Differential Thermal Analysis.
[0028] "Ceramic" includes amorphous material, glass, crystalline
ceramic, glass-ceramic, and combinations thereof.
[0029] "Glass" refers to amorphous material exhibiting a glass
transition temperature.
[0030] "Glass-ceramic" refers to ceramic comprising crystals formed
by heat-treating amorphous material.
[0031] "Inert gas" refers to helium, neon, krypton, argon, xenon,
nitrogen and combinations of two or more of the foregoing.
[0032] The various features of the disclosed embodiments will be
further understood by those skilled in the art upon consideration
of the remainder of the disclosure, including the Detailed
Description, the non-limiting Examples and the appended Claims.
BRIEF DESCRIPTION OF THE FIGURES
[0033] In describing the embodiments of the invention, reference is
made to the various Figures. It will be appreciated that the
Figures are not to scale but are provided as an aid in describing
the embodiments. The various features of the embodiments are
identified with reference numerals wherein like numerals generally
indicate like features, and wherein:
[0034] FIG. 1 is a plan view of a moldable article according to an
embodiment of the invention;
[0035] FIG. 2 is a side view of the moldable article of FIG. 1;
[0036] FIG. 3 is a schematic representation of a process for the
manufacture of the moldable article of FIG. 1 and also illustrating
the subsequent molding thereof;
[0037] FIG. 4 is a plan view of a moldable article according to
another embodiment of the invention;
[0038] FIG. 5 is a schematic representation of a process for the
manufacture of the moldable article of FIG. 4 and also illustrating
the subsequent molding thereof;
[0039] FIG. 6 is a plan view of a moldable article according to
another embodiment of the invention;
[0040] FIG. 7 is a perspective view of a moldable article according
to still another embodiment of the invention;
[0041] FIG. 8 is a perspective view of a molded article according
to still another embodiment of the invention;
[0042] FIG. 9 is a perspective of a molded article according to
still another embodiment of the invention;
[0043] FIG. 10 is a perspective of a molded article according to
still another embodiment of the invention; and
[0044] FIG. 11 is a perspective of a molded article according to
still another embodiment of the invention.
DETAILED DESCRIPTION
[0045] The invention provides for the handling of glass, including
non-traditional glass, wherein the glass is initially in the form
of particles (spherical particles, fibers, microspheres, etc..).
The embodiments of the invention provide moldable articles
comprising glass particles, processes for the preparation of
moldable articles and processes for molding. In the various
embodiments, moldable articles are provided in the form of a sealed
container or package containing glass particles in a moisture-free,
controlled and/or treated atmosphere. The moldable articles
described herein may be inserted directly into a mold cavity. A
molding operation is performed by the application of heat/pressure
to the moldable article without removing the glass particles from
the package. The molding process is carried out at temperatures
above the decomposition temperature of the packaging material so
that the packaging essentially burns off during the molding
operation. The glass typically has a molding temperature (e.g., a
temperature at which the glass particles begin to coalesce)
significantly higher than the decomposition temperature of the
packaging material. At or above the molding temperature for the
glass, the glass particles coalesce and, upon cooling, provide a
molded article.
[0046] Referring now to the Figures, FIGS. 1 and 2 provide
different views of a moldable article 10 according to an embodiment
of the invention. The moldable article 10 is provided in the form
of a first package having a first barrier 12 defining a first
interior space 14 containing a predetermined amount (e.g., a
plurality) of glass particles 16. The first barrier 12 is sealed,
and the first interior space typically has an atmosphere different
than the atmosphere surrounding the article 10. In some
embodiments, the first interior space 14 has an atmosphere
substantially free of water vapor. In some embodiments, the first
interior space 14 has an atmosphere of inert gas. In other
embodiments, the atmosphere in first interior space 14 is at least
partially evacuated to a reduced pressure (e.g., vacuum or near
vacuum).
[0047] First barrier 12 is made of a flexible first material that
is substantially gas impermeable in order to maintain a
substantially constant atmosphere within the first interior space
14. While the article 10 remains sealed, glass particles 16 and
first interior space 14 remain substantially dry or water-free.
[0048] Suitable flexible first materials include paper as well as
various flexible polymer materials. As used herein, the term
"flexible" refers to a property, and materials having such a
property typically lack rigidity or stiffness under ambient
conditions. In other embodiments, first barrier may be made of a
more rigid first material. As used herein, the term "rigid" refers
to a property, and a material having such a property tends to
maintain a given shape at ambient temperatures in the absence of
excess heat or external forces exerted on the material. However, a
rigid material need not be entirely inflexible and, in fact, some
rigid materials may be bent or otherwise deformed when heated,
handled or the like. It will be appreciated that the differences
between a rigid material and a flexible material may be accounted
for, in some instances, by the use of different materials or by
variations in the thickness of the same or similar material (e.g.,
increasing the thickness of a material can provide rigidity).
[0049] Polymers suitable for use as the first material include
those selected from the group consisting of polyamide, poly methyl
methacrylate, polyisobutylene, polycarbonate, polyethylene
carbonate, polypropylene carbonate, polybutylene terephthalate,
polyetheretherketone, polyethylene, polypropylene, polyphenylene
oxide, polystyrene aromatic polyesters, and combinations of two or
more of the foregoing. Suitable polyamides include nylon 6 and
nylon 66 and combinations thereof. Suitable polyethylenes can be
selected from low density polyethylene, high density polyethylene,
medium density polyethylene and combinations of two or more of the
foregoing. In specific embodiments, the first barrier is made with
low density polyethylene. The first material has a first
decomposition temperature at which the material decomposes.
[0050] Glass particles 16 occupy the first interior space 14. In
embodiments of the invention, the particles 16 are microparticles
comprising a first glass material that is a non-traditional glass
material such as those described in patents and patent applications
that include U.S. Ser. Nos. 09/922,527, 09/922,528, and 09/922,530,
filed Aug. 2, 2001; U.S. 2003/0115805 A1 (Rosenflanz et al.); U.S.
2003/0110707 A1 (Rosenflanz et al.); U.S. Pat. No. 7,168,267
(Rosenflanz et al.); U.S. 2003/0126802 A1 (Rosenflanz); U.S. Pat.
No. 7,147,544 (Rosenflanz et al.); and U.S. Pat. No. 7,101,819
(Rosenflanz et al.), the disclosures of which are incorporated
herein by reference.
[0051] The aforementioned non-traditional glass materials have a
first glass transition temperature and a first crystallization
onset temperature. The difference between the first glass
transition temperature and the first crystallization onset
temperature is at least about 5.degree. K. (or even, at least
10.degree. K., at least 15.degree. K., at least 20.degree. K., at
least 25.degree. K., at least 30.degree. K., or at least 35.degree.
K.). The first glass material comprises at least two metal oxides
(i.e., the metal oxides do not have the same cation(s)), from 0 to
less than 20% by weight SiO.sub.2 (e.g., less than 15%, less than
10%, less than 5% by weight, or even zero percent, by weight,
SiO.sub.2), from 0 to less than 20% by weight B.sub.2O.sub.3 (e.g.,
less than 15%, less than 10%, less than 5% by weight, or even zero
percent, by weight, B.sub.2O.sub.3), and from 0 to less than 40% by
weight P.sub.2O.sub.5 (e.g., less than 35%, less than 30%, less
than 25%, less than 20%, less than 15%, less than 1%, less than 5%
by weight, or even zero percent, by weight, P.sub.2O.sub.5). The
foregoing glass materials are moldable at or above a first molding
temperature at which the microparticles begin to coalesce. In the
embodiments of the invention described herein, the first
decomposition temperature of the first material is lower than the
first molding temperature of the first glass.
[0052] Referring to FIG. 3, a process for the preparation of
moldable article 10 is schematically shown along with a molding
process involving the article. A measured quantity of glass
particles 16 are heated within a container 20 at a heating station
(not shown) such as an oven, a heating mantle or the like. The
particles 16 are heated to an elevated temperature below the
T.sub.g of the glass for a sufficient time to remove water. In some
embodiments, the particles are held at a temperature near the
boiling point of water (e.g., 100.degree. C.). In some embodiments,
a suitable temperature is in the range from about 101.degree. C. to
about 150.degree. C., from about 110.degree. C. to about
140.degree. C., and from about 120.degree. C. to about 135.degree.
C. In some embodiments, a suitable temperature is about 130.degree.
C. The amount of time the particles are heated can depend on the
volume of particles being used as well as the amount of moisture
present. In various embodiments, heating for several hours is
desired to ensure the particles are adequately dry, and the
particles can be heated for up to about 24 hours at a temperature
in one of the foregoing ranges.
[0053] Once dried, container 20 may be sealed (not shown) and the
glass particles 16 are allowed to cool before being transferred
from container 20 into sealable flexible container 26. Funnel 28 is
shown as an optional means to facilitate the transfer of the
particles 16. Following transfer of the glass particles, sealable
container 26 is filled with a quantity of dried particles, and the
container 26 can be sealed along its opened end 30 to provide
moldable article 10 with an interior space 14 that is substantially
moisture-free. In some embodiments, sealable container 26 is purged
with inert gas prior to sealing. In some embodiments, the container
26 is sealed to have a reduced pressure within first interior space
14. In some embodiments, container 26 is sealed to provide a vacuum
or near vacuum conditions within interior space 14.
[0054] The moldable article 10 is suitable for use in a molding
process to mold the glass particles 16 into a molded article. In
embodiments in which the glass particles 16 are in the form of
microparticles, they may be of an average diameter measured in
micrometers, and in some embodiments in the range from about 10
.mu.m to about 250 .mu.m. In any event, the glass particles 16 are
moldable at a first molding temperature at or above about
300.degree. C., at or above about 400.degree. C., at or above about
500.degree. C., at or above about 700.degree. C. or at or above
about 900.degree. C. In the molding process, moldable article 10 is
placed in mold cavity 34 of mold 32. In the embodiment of FIG. 3,
the depicted molding process is compression molding, and cavity 34
is equipped to be heated to an elevated temperature. With moldable
article 10 in the cavity 34, mold 32 is closed with a top or plug
member 36 dimensioned to fit within the cavity 34 to apply pressure
to the material within the mold.
[0055] The mold 32 is heated to a first molding temperature and the
mold is pressurized by the compression exerted by plug member 36.
In the various embodiments of the invention, the first barrier of
the moldable article 10 comprises a first material (e.g.,
polyethylene) having a decomposition temperature lower than the
first molding temperature of the glass particles so that the first
material of barrier 12 decomposes during the molding process and
typically before the particles 16 begin to soften and coalesce. In
some embodiments, decomposition of the first barrier 12 removes
substantially all of the first material of the barrier. As the
temperature within mold 32 continues to rise to the first molding
temperature, the glass particles begin to soften, coalesce and
assume a shape that is consistent with the interior configuration
of cavity 34. The mold 32 is then cooled to form the molded article
38 which may then be removed from the cavity 34.
[0056] In embodiments, the non-traditional glass particles are
coalesced and are at least partially crystallized to provide a
glass-ceramic article or a ceramic article. In some embodiments,
the glass is heat treated to increase the crystallinity of the
glass and provide glass-ceramic or ceramic material. Those skilled
in the art will appreciate that the molded article 38 may comprise
glass, glass-ceramic and/or ceramic material.
[0057] In embodiments of the invention, the surfaces of the molded
article 38 are of optical quality without further processing. In
such embodiments, the surfaces of the article 38 assume the
topography imparted by the interior surfaces of the mold 32. As
used herein, "optical quality" refers to the suitability of a
surface or article for use in applications in the optics field.
[0058] In some embodiments, the first material may not completely
decompose during the molding process, and the surfaces of the
molded article 38 may be polished and/or further treated (e.g.,
with solvent) to remove remaining residue.
[0059] Referring to FIG. 4, another embodiment of a moldable
article 110 is shown. Article 110 includes first barrier 112
defining an interior space divided into a first interior space 114a
and a second interior space 114b. Interior spaces 114a, 114b are
depicted as substantially equal in their interior capacity or
volume, with the two spaces being separated by a single partition
113. As previously described for the article 10 of FIG. 1, the
atmospheres in each of the interior spaces 114a and 114b may be
different than the atmosphere surrounding the moldable article 110,
and it will be appreciated that interior spaces 114a, 114b may have
inner atmospheres that are the same as one another or they may be
different from one another. The atmospheres in interior spaces 114a
and/or 114b are substantially free of moisture, and in some
embodiments, the interior spaces comprise inert gas. In some
embodiments, interior spaces 114a and/or 114b have been evacuated
to provide a vacuum or near vacuum state.
[0060] A volume of first glass particles 116a comprising a first
glass are included within the first interior space 114a. Likewise,
a predetermined amount of second glass particles 116b are included
within the second interior space 114b. The amount of first
particles 116a in interior space 114a may be the same as or
different than the amount of second particles 116b within interior
space 114b. Second particles 116b comprise a second glass. At least
one of the first glass or the second glass comprise non-traditional
glass materials, as previously described. First glass and second
glass may be the same glass material or they may be different.
[0061] In some embodiments of the invention, second glass particles
116b are identical to first glass particles 116a in that the first
glass is of the same composition as the second glass. In other
embodiments, the first glass is of a different composition than
that of the second glass.
[0062] In embodiments wherein both first and second glasses are
non-traditional glasses, at least one of the glasses may comprise
less than 40 percent (or less than 35%, 30%, 25%, 20%, 15%, 10%, 5%
or even 0%) by weight glass collectively SiO.sub.2, B.sub.2O.sub.3,
and P.sub.2O.sub.5, based on the total weight of the glass. The
plurality of second particles are moldable at a second molding
temperature in that they will begin to soften and coalesce (e.g.,
during a molding operation) at or above the second molding
temperature, and the second molding temperature may be the same as
or different than the first molding temperature. In the various
embodiments, the first decomposition temperature is less than both
the first molding temperature and the second molding
temperature.
[0063] First barrier 112 is made from materials as previously
described with reference to the moldable article 10 (FIG. 1).
Partition 113 is typically made from the same material as first
barrier 112, although some embodiments may include a partition made
from material different than that used for barrier 112.
[0064] Referring to FIG. 5, a schematic illustration of a process
is shown for the manufacture of the moldable article 110 and for
its subsequent use in a molding process to provide a molded glass
article 138. A measured quantity of first glass particles 116a are
initially heated within a container 120 to remove water, and a
measured quantity of second glass particles 116b are heated in a
second container 121, also to remove water. The containers 120, 121
may be heated at a separate heating station (not shown) which can
include an oven, a heating mantle or the like.
[0065] Following heating to remove moisture, the containers 120 and
121 may be sealed to prevent moisture from returning to the
particles as they are allowed to cool. First glass particles 116a
are transferred from container 120 into the first interior space
114a of sealable container 126. Funnel 128 is shown as an optional
means to facilitate the transfer of the glass particles 116a.
Second glass particles 116b are transferred from container 121 into
the second interior space 114b of sealable container 126. Funnel
129 is shown as an optional means to facilitate the transfer of the
particles 116b. Following transfer of the glass particles, sealable
container 126 is sealed along its opened side 130 to provide
moldable article 110.
[0066] In some embodiments of the invention, the sealable container
126 is purged with inert gas prior to sealing. In other
embodiments, interior spaces 114a and 114b are sealed following
evacuation to provide a reduced pressure (e.g., vacuum or near
vacuum conditions) within the interior spaces.
[0067] The moldable article 110 is suitable for use in a molding
process in which the article is placed in an opened mold cavity 134
of mold 132 with the respective interior spaces 114a and 114b
oriented with respect to one another so that one of the interior
spaces and its contents (e.g., the glass particles 116a or 116b)
lay on top of the other interior space and its contents. In this
orientation, particles 116a and 116b form two layers of glass
material, stacked one on top of the other. In the compression
molding process of FIG. 5, cavity 134 is initially opened to
receive the article 110 and is configured to be heated to an
elevated temperature. With moldable article 110 disposed within
cavity 134, the mold 132 is closed and is heated to a predetermined
temperature. Pressure is applied to the article 110 with plug
member 136 to compress the glass particles within the cavity
134.
[0068] In the various embodiments of the invention, the first
barrier 112 of the moldable article 110 will substantially
decompose at or above a characteristic decomposition temperature.
In some embodiments, decomposition of the first barrier 112 removes
substantially all of the first material of the barrier. Thereafter,
the temperature of the mold 132 is increased to heat the glass
particles 116a and 116b to a molding temperature at which the
particles will soften and coalesce. The mold 132 is cooled and the
resulting molded article 138 may be removed from the cavity 134.
Molded article 138 is a two layered composite with a first layer
138a resulting from molding of the first particles 116a and the
second layer 138b resulting from the second particles 116b. In some
embodiments, the first material of first barrier 112 may not
completely decompose during the molding process so that the
surfaces of the molded article 138 may require polishing and/or
another treatment (e.g., cleaning with a solvent) to remove any
remaining residue. At least one of the layers 138a or 138b comprise
a material derived from a non-traditional glass, as described
herein.
[0069] In still other embodiments, molded articles similar to
molded article 138 may be made by stacking individual moldable
articles (e.g., similar to article 10, FIG. 1) in a mold cavity and
molding the moldable articles in the same manner as previously
described. Multilayered articles similar to article 138 may be
particularly useful as optical lenses, for example. In such
embodiments, molded layers 138a and 138b may each have one or more
different properties such as different refractive indexes or the
like. In various embodiments, molded article 138 may comprise
glass, ceramic and/or glass-ceramic material resulting from the
molding of non-traditional glass. In some embodiments, the
non-traditional glass particles are coalesced and are at least
partially crystallized. In some embodiments, the glass is heat
treated in a manner that increases the crystallinity of the glass
and provides glass-ceramic or ceramic material.
[0070] Referring now to FIG. 8, a multilayered molded article 168
is shown. The article 168 may be made according to an embodiment of
the invention. Molded layers 168a, 168b, and 168c occupy discrete
positions within the stacked arrangement. In some embodiments, each
of the molded layers 168a, 168b, and 168c is made from a different
glass composition to provide a molded layer with a refractive index
that is different than the refractive index of either of the other
two layers. In embodiments in which the article 168 is a gradient
index lens, for example, layers 168a and 168c may comprise a high
refractive index glass while the middle layer 168b may be made of a
low refractive index glass. At least one of the layers 168a, 168b,
and/or 168c is the molded product of a non-traditional glass, as
previously described, and molding of the non-traditional glass may
result in glass, ceramic and/or glass-ceramic materials in one or
more of the layers 168a, 168b or 168c of molded article 168. The
article 168 may be made from a moldable article comprising three
different interior spaces, for example, each interior space
containing a separate set of glass particles. Alternatively, the
article 168 may be made by simultaneously molding three moldable
articles stacked on top of one another within a mold cavity, each
moldable article containing its own separate set of glass
particles. Through the molding process, as previously described,
each of the moldable articles would result in the creation of a
layer in the finished article 168.
[0071] FIG. 6 depicts a moldable article 210 configured according
to still another embodiment of the invention. Article 210 is a
container having a first barrier 212 and an interior space divided
into a first interior space 214a and a second interior space 214b.
Interior spaces 214a, 214b each have inner atmospheres as
previously described with respect to the embodiments of FIGS. 1 and
4. A predetermined amount of first glass particles 216a are
included within the first interior space 214a, and a predetermined
amount of second glass particles 216b are included within second
interior space 214b. In the depicted embodiment, interior space
214a is larger than interior space 214b, and the amount of first
particles 216a in first interior space 214a is greater than the
amount of second particles 216b within second interior space 214b.
As in the previous embodiments, the particles 216a are of a first
glass composition which may be different than the second glass
composition of particles 216b. In general, first and second glass
particles may be selected to provide different properties to the
final molded article such as different refractive indexes, for
example. At least one of the first glass particles 216a or the
second glass particles 216b comprise non-traditional glass, as
previously described.
[0072] Moldable article 210 may be made using a combination of
individual containers wherein first barrier 212 is made of a
flexible material such as a polymeric material, as already
described. In such an embodiment, the single container is a `bag`
or a flexible-walled container with a single opened end leading
into its interior space. Second interior space 214b may be created
by providing heat sealed edges 215a, 215b, 215c to form three sides
of the second interior space 214b. A fourth heat sealed edge 215d
is formed after the interior space 214b is filled with glass
particles 216b. In FIG. 6, second interior space 214b is positioned
in the center of first interior space 214b. Alternatively, the
second interior space may be positioned elsewhere within the larger
first interior space 214b, depending on the configuration desired
for the final molded article. It will also be appreciated that, in
some embodiments, more than two interior spaces (e.g., a third
interior space, a fourth interior space and the like) may be
associated with the same moldable article, each such interior space
containing a volume of glass particles with at least one of the
volumes of glass particles comprising a non-traditional glass, as
previously described.
[0073] Moldable article 210 may be used in a molding process, as
previously described with respect to the embodiments of FIGS. 1-5.
The resulting molded article will include at least two different
molded portions, one of the molded portions resulting from
processing of the first glass particles 214a and another molded
portion made from processing of the second glass particles
214b.
[0074] Molded article 238, shown in FIG. 9, is of the type obtained
from a molding process involving moldable article 210 of FIG. 6.
Article 238 includes a first or outer molded portion 238a and a
second or inner molded portion 238b nested within and affixed to
the outer portion 238a. It will be appreciated that the depicted
shapes of molded portions 238a, 238b are merely illustrative, and
that other shapes are within the scope of this disclosure and may
be readily obtained merely by altering the design of the mold used
to make the molded articles, for example. At least one of the
layers of the molded article 238 results from the molding of
non-traditional glass materials, as previously described, so that
such a layer may comprise glass, ceramic and/or glass-ceramic
materials.
[0075] Other embodiments are contemplated wherein the moldable
article is similar to the article 210 in FIG. 6, but wherein the
second interior space (e.g., comparable to space 114b) is actually
comprised of a separate moldable article placed within the interior
space of a larger moldable article (e.g., comparable to interior
space 214a). In other words, embodiments of the invention include
those wherein separate moldable articles are included in the
interior space of another moldable article. Each of the separate
interior spaces of each moldable article include a volume of glass
particles. At least one of the volumes of glass particles comprise
a non-traditional glass, as previously described.
[0076] In still other embodiments, molded articles may be made
according to the present invention wherein the articles include
both glass and non-glass portions affixed to one another. Article
338 is depicted in FIG. 10 and includes two components, molded
glass portion 338b placed within a circular, non-glass, first
portion 338a (e.g., a frame). Molded glass portion 338b comprises a
non-traditional glass as previously described. The circular
non-glass portion 338a may be made from any of a variety of other
materials including polymeric materials, metallic materials or the
like. Prior to forming the finished molded article 338, the
non-glass portion 338a may be pre-formed and placed within a mold
cavity. In the molding operation, the non-glass portion 338a is
placed in the mold and a moldable article (as described herein) is
positioned in the center of the non-glass portion 338a within the
mold. A molding process may be performed to form article 338 having
molded glass portion 338b positioned within the center of portion
338a. During the molding operation, glass particles in the moldable
article coalesce while also bonding to the non-glass portion to
form a finished article 338 with portions 338a and 338b affixed to
one another.
[0077] The person of ordinary skill in the art will appreciate that
other multi-component articles may also be made using the moldable
articles of the present invention. Such multi-component molded
articles can include glass and non-glass portions arranged as
needed or desired. Another such multi-component molded article 448
is depicted in FIG. 11. The article 448 includes three components
448a, 448b, and 448c. At least one of the molded components
comprises a material derived from a non-traditional glass, as
previously described. Article 448 results from molding at least one
moldable article, as described herein.
[0078] In still another embodiment, a moldable article 310 is
depicted in FIG. 7. As in the previously described embodiments,
article 310 is a container having a first barrier 312. Instead of
being flexible, however, first barrier 312 is made of a shaped,
more rigid, material. In FIG. 7, the molded article 310 has a
hemispherical shape with a concave center portion 311 (e.g., it is
cup-shaped). A plurality of glass particles 316 occupy interior
space 314 within the article 310, and the interior space 314 has a
substantially moisture-free inner atmosphere, as previously
described. First barrier 312 comprises a first material that will
decompose as the mold is heated and pressurized during a molding
operation. Decomposition of the barrier 312 occurs at a
decomposition temperature substantially less than the molding
temperature of the glass particles 316. Moldable article 310 is
shaped to nest within the mold cavity 334, with center portion 311
dimensioned to receive the mold's plug member 336 therein. Molding
the cup-shaped article 310 results in a similarly shaped molded
article. While the shape of article 310 has been somewhat
exaggerated for the purposes of describing this embodiment, it will
be appreciated that shape of the moldable article will facilitate
the formation of a similarly shaped molded article such as a
concave optical lens, for example.
[0079] Use of a rigid first material for the barrier 312 serves to
hold the plurality of glass particles 316 in a predetermined
cup-shaped configuration. In the compression molding process,
cavity 334 is heated to an elevated temperature and pressure is
applied to the article 310 with plug member 336 extending from the
mold top 335 into concave center portion 311. As the mold reaches
the decomposition temperature of the first material, the barrier
312 will decompose and the glass particles 316 will soften and
coalesce. As the temperature continues to rise to the first molding
temperature, the particles 316 begin to soften and to coalesce into
a molded form. Upon cooling, the glass will solidify and the molded
article can be removed from the mold cavity 334. The resulting
molded article may comprise glass, glass-ceramic and/or ceramic
material.
[0080] It will also be appreciated by the person of ordinary skill
that variations to the rigid moldable article 310 are obtainable
and are entirely within the scope of the invention. For example,
the molded article may be provided in a different shape and/or with
multiple chambers, each chamber including a separate plurality of
glass particles therein, with at least one of the chambers
containing a plurality microparticles comprising non-traditional
glass materials as previously described. All such embodiments are
within the scope of the invention.
[0081] The use of a moldable article according to an embodiment of
the invention, provides an improved molding process for glass
particles, and especially for glass microspheres. The various
embodiments of the invention provide a means to initially prepare a
plurality of glass particles for a molding process and thereafter
preserve the particles in a ready-state for an undetermined period
of time. Moisture as well as carbon and dirt are known contaminants
in the molding of small particles such as microspheres. Such
contaminants may be picked up by handling the particles, during
placement of the particles into a mold cavity, and/or during
pressurization of the mold cavity. Contamination can be problematic
because it can cause structural defects in the final molded glass
article. In the molding of optical lenses, for example, structural
defects can result in undesirable optical properties in the
finished lens. In addition to contamination caused be dirt or the
like, small particles (e.g., microparticles) can pick up static
charge that further complicates the handling of the particles,
especially during placement of the particles into a mold cavity,
for example.
[0082] The moldable articles of the invention facilitate the
molding process by allowing for the easy deposition of glass
particles into a mold cavity without concern for retained moisture
and without the difficulties of handling particles that are
statically charged. A maker of glass particles, for example, can
utilize the invention to prepare the particles for a molding
operation that may be performed by an outside vendor, a customer or
the like. Vendors and customers using the glass particles in a
molding process are thus assured of the purity and cleanliness of
the packaged particles. Moreover, any of a variety of molded
articles may be provided including, for example, single layered
articles as well as multilayered articles.
EXAMPLES
[0083] The following non-limiting Examples further illustrate the
embodiments of the present invention.
Example 1
[0084] Twenty grams of glass microparticles were deposited in a
glass jar and dried in an oven for 16 hours at 130.degree. C. The
microparticles were made of a non-traditional glass having a
composition represented as La.sub.2O.sub.3 Al.sub.2O.sub.3
Zr0.sub.2 Gd.sub.2O.sub.3. The jar was sealed and allowed to cool.
The microparticles were poured into a flexible container (e.g., an
envelope) made of 2 mil (0.051 mm) polyethylene film and the
envelope was heat sealed. The envelope was positioned in a mold
cavity. The mold was heated to .about.900.degree. C. and
pressurized, burning off the polyethylene film and reshaping the
spherical microparticles into a consolidated article with the shape
of the mold cavity. The mold was cooled and the glass article was
removed and the surfaces were polished. A clear molded glass
article was produced.
Example 2
[0085] Five hundred grams of La.sub.2O.sub.3 Al.sub.2O.sub.3
Zr0.sub.2 Gd.sub.2O.sub.3 spherical glass microparticles were
dried, placed in a flexible polyethylene envelope and heat sealed
to provide a moldable article made of 4 mil (0.102 mm) thick
polyethylene film. Carbon plates were used to construct a mold
cavity having the dimensions of 5 in..times.5 in..times..about.3/8
in. (12.7 cm.times.12.7 cm.times.0.95 cm). The moldable article was
positioned in this mold cavity and the cavity was covered and
sealed with additional carbon plates. The mold was heated to
870.degree. C. and pressurized, compressing the microparticles into
a solid molded article. The polyethylene film was burned off during
the heating process.
[0086] While various embodiments have been described and
exemplified herein, the person of ordinary skill in the art will
appreciate that changes and modifications may be made to the
described embodiments without departing from the spirit and scope
of the invention.
* * * * *