U.S. patent application number 14/742275 was filed with the patent office on 2016-12-22 for method of glass fabric production including resin adhesion for printed circuit board formation.
The applicant listed for this patent is International Business Machines Corporation. Invention is credited to Sarah K. CZAPLEWSKI, Joseph KUCZYNSKI, Jason WERTZ, Jing ZHANG.
Application Number | 20160368821 14/742275 |
Document ID | / |
Family ID | 57587443 |
Filed Date | 2016-12-22 |
United States Patent
Application |
20160368821 |
Kind Code |
A1 |
CZAPLEWSKI; Sarah K. ; et
al. |
December 22, 2016 |
METHOD OF GLASS FABRIC PRODUCTION INCLUDING RESIN ADHESION FOR
PRINTED CIRCUIT BOARD FORMATION
Abstract
Embodiments generally relate to devices and methods for
production of fibers and threads for use in electronic device
manufacturing. Described here, fibers can be produced and
manipulated using a dual-surfaced sizing material. The
dual-surfaced sizing material has a surface which binds a fiber and
a surface which binds a resin. Thus, the dual-surfaced sizing
material can be left attached to the fibers without adversely
affecting the resin binding in later production steps.
Inventors: |
CZAPLEWSKI; Sarah K.;
(Rochester, MN) ; KUCZYNSKI; Joseph; (North Port,
FL) ; WERTZ; Jason; (Pleasant Valley, NY) ;
ZHANG; Jing; (Poughkeepsie, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
International Business Machines Corporation |
Armonk |
NY |
US |
|
|
Family ID: |
57587443 |
Appl. No.: |
14/742275 |
Filed: |
June 17, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H05K 1/0306 20130101;
C01P 2004/61 20130101; B05D 3/002 20130101; C03B 19/1065 20130101;
C03C 25/255 20180101; H05K 1/038 20130101; H05K 2201/029 20130101;
C03C 25/28 20130101; C03C 25/40 20130101; B05D 2203/35 20130101;
C03C 25/1095 20130101; C09C 1/3072 20130101; C09C 1/309 20130101;
H05K 2201/0251 20130101; H05K 1/0366 20130101; D03D 1/0082
20130101; C09C 1/3081 20130101; D03D 15/0011 20130101 |
International
Class: |
C03C 25/40 20060101
C03C025/40; B05D 3/00 20060101 B05D003/00; H05K 1/03 20060101
H05K001/03; C03C 25/28 20060101 C03C025/28; C03C 25/10 20060101
C03C025/10 |
Claims
1. An electronic device material, comprising: a plurality of fibers
comprising glass, the fibers having a sizing material on at least a
portion of a surface of at least one of said fibers, the sizing
material comprising: a silicon-containing core having a first
exposed region and a second exposed region, the first exposed
region having a resin binding functionalizing material and the
second exposed region having a silanizing material, the first
exposed region having an anisotropic surface chemistry as compared
to the second exposed region.
2. The electronic device material of claim 1, wherein the plurality
of fibers are formed into a plurality of strands.
3. The electronic device material of claim 2, wherein the plurality
of strands are woven into a cloth.
4. The electronic device material of claim 3, further comprising a
resin, the cloth being impregnated with the resin.
5. The electronic device material of claim 4, further comprising a
lamination formed over the cloth and the resin.
6. The electronic device material of claim 1, wherein the
silanizing material comprises Si(OEt).sub.3.
7. The electronic device material of claim 1, wherein the resin
binding functionalizing material is selected from the group
consisting of alkenyls, amines, epoxies, allyls, or acrylates.
8. The electronic device material of claim 1, wherein the resin
binding functionalizing material comprises vinyl.
9. The electronic device material of claim 1, wherein the first
exposed region and the second exposed region have a defined
boundary.
10-20. (canceled)
Description
BACKGROUND
[0001] Embodiments described herein generally relate to the
production of glass cloth for use in printed circuit boards.
[0002] Printed circuit boards are typically formed from laminated
layers of fabric composed of reinforcing fibers, such as glass
fibers. The reinforcing fibers provide dimensional stability to the
board to maintain the integrity of the electronic circuits mounted
thereon. Holes are formed in the board by drilling through the
layers of the laminate or support to interconnect circuits through
different planes.
[0003] Manufacturing of glass fibers that are used in printed
circuit boards require many steps prior to the use of the fabric
within laminates. In the first step, molten glass is extruded
through holes to produce the glass fibers. Next, the fibers pass
through a zone where a sizing material, such as a starch-oil
emulsion, is added to the individual fibers. The sizing material is
needed as it protects the fibers from abrasion and prevents surface
defects. Then, the fibers are formed together to create strands of
glass fiber that is then wound onto spools. After spooling, the
strands are then woven to generate the glass cloth.
[0004] In the case of composites or laminates formed from fiber
strands woven into fabrics, in addition to providing good
wet-through and good wet-out properties of the strands, the
surfaces of the fiber strands are then coated to protect the fibers
from abrasion during processing, provide for good weavability,
particularly on air-jet looms and preventing damage to the fibers
during the weaving process. However, many sizing components are not
compatible with the resin and can adversely affect adhesion between
the glass fibers and the polymeric matrix material. For example,
the starch-oil emulsion, which is a commonly used sizing component
for glass fibers, is generally not compatible with resin. As a
result, these incompatible materials must be removed from the
fabric prior to impregnation with the resin.
[0005] The removal of such non-resin compatible sizing materials
(also referred to as de-greasing or de-oiling the fabric) can be
accomplished through a variety of techniques. The removal of these
non-resin compatible sizing materials is most commonly accomplished
by exposing the woven fabric to elevated temperatures for extended
periods of time to thermally decompose the sizing materials
(commonly referred to as "heat-cleaning"). A conventional
heat-cleaning process involves heating the fabric at 380.degree. C.
for 60-80 hours. However, such heat cleaning steps are detrimental
to the strength of the glass fibers, are not always completely
successful in removing the incompatible materials and can further
contaminate the fabric with sizing decomposition products. Other
methods of removing sizing materials are available, such as water
washing and/or chemical removal. However, such methods generally
require significant reformulation of the sizing compositions for
compatibility with such water washing and/or chemical removal
operations and are generally not as effective as heat-cleaning in
removing all the incompatible sizing materials. Further,
heat-cleaning, water washing or chemical removal operations all add
to the cost of production as well as the time expenditure.
[0006] After weaving, the fabric must be modified to allow the
cloth to bond with the resin used in the lamination step to produce
printed circuit boards. A silane modifier is used to treat the
fabric. On one end of the silane modifier is a functionality for
bonding the fibers within the fabric. On the other end of the
silane modifier is a functionality for bonding to the resin
material. This enhances the adhesion between the cloth and the
resin. The now treated glass cloth can be impregnated with resin
and then used to form the laminate.
[0007] As such, there is a continuing need in the art for methods
and systems for glass fiber printed circuit board manufacture which
reduce cost of production while maintaining or increasing resulting
quality.
SUMMARY
[0008] Embodiments described herein generally relate to devices and
methods for creating a dual surfaced sizing material and uses for
the same. In one embodiment, an electronic device material can
include a plurality of fibers comprising glass, the fibers having a
sizing material on at least a portion of a surface of at least one
of said fibers, the sizing material comprising: a
silicon-containing core having a first exposed region and a second
exposed region, the first exposed region having a resin binding
functionalizing material and the second exposed region having a
silanizing material, the first exposed region having an anisotropic
surface chemistry as compared to the second exposed region.
[0009] In another embodiment, a method of producing an electronic
device material includes extruding a plurality of fibers, the
fibers comprising glass; coating at least a portion of a surface of
the fibers with a sizing material, the sizing material having an
anisotropic surface chemistry on a first exposed region and a
second exposed region, the first exposed region interacting with
the portion of the surface of the at least one of said fibers; and
forming the plurality of fibers into a plurality of strands.
[0010] In another embodiment, a method of producing a sizing
material, includes forming a silicon-containing core; exposing the
silicon-containing core to a surfactant; embedding the
silicon-containing core in a lipophilic component of an emulsion,
the silicon-containing core having a first surface and a second
surface, the silicon-containing core being embedded such that the
first surface is exposed and the second surface is obstructed by
the lipophilic component; washing the first surface to create a
clean first surface; exposing the clean first surface to a
resin-binding functionalizing material; removing the lipophilic
component to expose the second surface; and exposing the second
surface to a silanizing agent.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] So that the manner in which the above recited features of
the present devices, systems and methods can be understood in
detail, a more particular description of the devices, systems and
methods, briefly summarized above, may be had by reference to
embodiments, some of which are illustrated in the appended
drawings. It is to be noted, however, that the appended drawings
illustrate only typical embodiments and are therefore not to be
considered limiting of its scope, for the devices, systems and
methods may admit to other equally effective embodiments.
[0012] FIG. 1 is a schematic of a forming apparatus, such as is
used in glass fiber extrusion;
[0013] FIG. 2 is a flow diagram of a method of forming a sizing
material, according to one embodiment;
[0014] FIGS. 3A-3H depict the formation of the sizing material, as
described in FIG. 2; and
[0015] FIG. 4 is a flow diagram of a method of forming a board,
according to one embodiment.
[0016] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. It is contemplated that elements
disclosed in one embodiment may be beneficially utilized on other
embodiments without specific recitation.
DETAILED DESCRIPTION
[0017] Embodiments described herein generally relate to devices and
methods for creating a dual surfaced sizing material and uses for
the same. The fibers are coated with a sizing material having two
surfaces, one surface having a binding affinity for a resin and the
other surface having a binding affinity for the fiber. Because the
sizing material does not negatively affect the resin binding to the
fibers, the fibers can be converted to threads, woven into fabrics
and otherwise processed without removal of the sizing material.
Thus, the resulting circuit board substrate can be created with
lower energy input, fewer steps and shorter time to completion than
devices made using other methods.
[0018] FIG. 1 depicts a schematic of a forming apparatus 100, such
as is used in glass fiber extrusion. The forming apparatus includes
a furnace 101, one or more bushings 110, one or more applicators
114, one or more gathering shoes 116, one or more spirals 120 and
one or more take-up devices, shown here as a winder 122 with a
collet 124.
[0019] Prior to being extruded as glass fibers, the batch
ingredients (e.g., glass) undergo a batch mixing and melting
process. The batch mixing and melting process begins with the
weighing and blending of the batch ingredients. The individual
components of the batch ingredients are weighed and delivered to a
blending station (not shown). The blending station thoroughly mixes
the batch ingredients before the ingredients are transported to a
furnace 101.
[0020] The furnace 101 is generally divided into three distinct
sections, a furnace section 102, a refiner section 104 and a
forehearth 106. The batch ingredients are first delivered into the
furnace section 102 for melting the batch ingredients. The furnace
section 102 melts the batch ingredients into a molten glass 108. In
one example, the furnace section 102 can be maintained at between
1500 degrees Celsius and 1600 degrees Celsius, to create a molten
glass temperature of about 1370 degrees Celsius. The melting
process also includes the removal of gaseous inclusions and
homogenization of the molten glass 108. Then, the molten glass 108
flows into the refiner section 104. The temperature of the glass in
the refiner section 104 is lowered, such as from the above example
of about 1370 degrees Celsius to about 1260 degrees Celsius. The
molten glass 108 next goes to the forehearth 106 located directly
above the fiber-forming stations. The temperatures throughout this
process are prescribed by the viscosity characteristics of the
particular glass. In addition, the physical layout of the furnace
can vary widely, depending on the space constraints.
[0021] The conversion of molten glass 108 in the forehearth 106
into continuous glass fibers is an attenuation process. In the
attenuation process as described herein, a larger flow of glass is
reduced to a much smaller flow by attenuating the flow, which upon
cooling becomes single strands. The molten glass 108 flows through
a bushing 110, such as a platinum-rhodium alloy bushing. The
bushing 110 has a large number of holes or tips. Eleven (11) holes
or tips are shown in FIG. 1, corresponding to eleven (11) fibers
112. In one embodiment, a bushing 110 can have between about 400
and about 8000 holes or tips. The bushing 110 can be heated
electrically. Further, the heat of the bushing 110 can be
controlled very precisely to maintain a constant glass viscosity.
The fibers 112 are drawn down and cooled rapidly as they exit the
bushing 110.
[0022] A sizing is then applied to the surface of the fibers by
passing the fibers over an applicator 114 that continually rotates
through a sizing bath to maintain a thin film through which the
fibers 112 pass. As used herein, the terms "size", "sized" or
"sizing" refer to the aqueous composition applied to the fibers 112
immediately after formation. A sizing bath is a container which
holds the sizing. The sizing compositions described herein can
include as components, among other constituents, film-formers,
lubricants, coupling agents, emulsifiers and water.
[0023] The fibers 112 can be formed from any type of fiberizable
glass composition known to those skilled in the art including those
prepared from fiberizable glass compositions such as "E-glass",
"A-glass", "C-glass", "D-glass", "R-glass", "S-glass" and E-glass
derivatives. In one example, glass fibers are formed from E-glass
and E-glass derivatives. The fibers 112 can have a nominal filament
diameter ranging from about 5.0 to about 35.0 micrometers.
[0024] After applying the sizing material, the fibers 112 are
gathered, or consolidated according to the natural filament split,
into strands 118 using a gathering shoe 116, before approaching the
take-up device 122. The gathering shoe 116 gathers selected groups
of the fibers 112 to form one or more strands 118. The strands 118
typically have about 100 to about 15,000 fibers per strand, such as
about 200 to about 7,000 fibers. The strands 118 can be drawn
through the gathering 116 at speeds of about 2,500 feet per minute
to about 18,000 feet per minute. Although not intended to be
limiting, the gathering shoe 116 shown in FIG. 1, forms one strand
118, but it should be appreciated that fibers 112 may be divided
into more strands 118, such as between 1 to about 20 strands.
Strands 118 can also be formed from fibers 112 drawn from a
plurality of adjacent bushings 110 (not shown).
[0025] The forming apparatus 100 also includes spiral 120. The
spiral 120 traverses the strands 118 along the length of the axis
of rotation of the rotatable collet 124 of the winder 122. The
spiral 120 thus maintains proper coiling of the strands 118 during
winding of the strands 118 about the surface of the collet 124.
[0026] FIG. 2 depicts a method 200 of forming a sizing material,
according to one embodiment. FIGS. 3A-3H depict a sizing material
300, an emulsion 320 and a sized fiber 350, as formed using the
method 200 of FIG. 2. The method 200 can include or sequentially
include forming a silicon-containing core, at 202; exposing the
silicon-containing core to a surfactant, at 204; embedding the
silicon-containing core in a lipophilic component of an emulsion,
the silicon-containing core having a first surface and a second
surface, the silicon-containing core being embedded such that the
first surface is exposed and the second surface is obstructed by
the lipophilic component, at 206; washing the first surface to
create a clean first surface, at 208; exposing the clean first
surface to a resin-binding functionalizing material, at 210;
removing the lipophilic component to expose the second surface, at
212; and exposing the second surface to a silanizing agent, at
214.
[0027] The sizing material formed by embodiments described herein
includes dual-surfaced particles. Each dual-surfaced particle has a
silane coupling agent on one side of the particle (i.e., a first
binding surface) and an organic functionality on the other side of
the particle (i.e., a second binding surface). The silane coupling
agent can bond to the glass fibers during the forming process. The
organic functionality that can bond to the resin used in the
laminate. By having a first binding surface and a second binding
surface, the sizing material does not need to be removed before
resin binding. Thus, the dual-surfaced particle allows for the
elimination of processing steps needed to form the substrate, such
as a circuit board substrate, and promotes adhesion between the
fibers and the resin.
[0028] The method 200 for forming a sizing material 300 begins at
202 with forming a silicon-containing core 302. The
silicon-containing core 302 can be produced in the micron to nano
size range, such as less than 1 micrometer (.mu.m). The
silicon-containing core 302 can be produced using a silica
precursor, such as tetraethoxysilane (TEOS). TEOS can then be added
to an excess of water containing a low molar-mass alcohol, such as
ethanol, and containing ammonia. The process is believed to take
place via monomer addition, in which nucleation occurs quickly and
is followed by a particle growth process without further
nucleation. However, this understanding is not intended to be
limiting of possible embodiments.
[0029] The diameter of silica particles from the Stober process is
controlled by the relative contribution from nucleation and growth
processes. The hydrolysis and condensation reactions provide
precursor species and the necessary supersaturation for the
formation of particles. During the hydrolysis reaction, the ethoxy
group of TEOS reacts with the water molecule to form the
intermediate [Si(OC.sub.2H.sub.5).sub.4-X(OH).sub.X] with hydroxyl
group substituting ethoxy groups. Ammonia works as a basic catalyst
to this reaction; the hydrolysis reaction is initiated by the
attacks of hydroxyl anions on TEOS molecules. The chemical reaction
is expressed as follows:
Si(OC.sub.2H.sub.5).sub.4+xH.sub.2O.fwdarw.Si(OC.sub.2H.sub.5).sub.4-x(O-
H).sub.x+xC.sub.2H.sub.5OH
[0030] Following the hydrolysis reaction, the condensation reaction
occurs immediately. Where the hydroxyl group of intermediate
[Si(OC2H5).sub.4-x(OH).sub.x] reacts with either the ethoxy group
of other TEOS "alcohol condensation" or the hydroxyl group of
another hydrolysis intermediate "water condensation" to form
Si--O--Si bridges. The rate of water condensation is believed to be
about thousands of times faster than the alcohol condensation. The
overall reaction is expressed as follows:
Si(OC.sub.2H.sub.5).sub.4+2H.sub.2O.fwdarw.SiO.sub.2+4C.sub.2H.sub.5OH
[0031] The resulting suspension is then stirred or otherwise
agitated. The resulting silicon-containing core 302 can have
diameters between 50 and 2000 nanometers. The diameter of the
resulting silicon-containing core 302 can be modified by changing
type of silicate ester used, type of alcohol used and volume
ratios. Silicate esters may generally include esters of
orthosilicic acid. Silicate esters which may be used with
embodiments described herein include tetraethyl orthosilicate,
tetramethyl orthosilicate, tetraphenyl orthosilicate, combinations
thereof and others. Alcohols may generally include organic
molecules having an OH group, such as alcohols that form an
homologous series with the general formula CnH2n+1OH. Alcohols
which may be used with embodiments described herein include
methanol, ethanol, n-propanol, n-butanol, combinations thereof and
others. In one embodiment, the concentrations for the resulting
suspension include 0.1M to 0.5M TEOS, 0.5M to 17.0M H.sub.2O and
0.5M-3M NH.sub.3 with the solvent in excess.
[0032] Using the above example, the reactions taking place are
hydrolysis of the silyl ether to a silanol. The silanol is then
condensed to silica by a condensation reaction.
[0033] The silicon-containing core 302 can be exposed to a
surfactant 304, at 204. As described here, the silicon-containing
core 302 is dispersed in an aqueous suspension, to which the
surfactant 304 is added. The hydrophilic surface of the
silicon-containing core 302 is made partially hydrophobic by
adsorbing the surfactant 304. The surfactant 304 may be an anionic
or cationic surfactant. In one embodiment, a cationic surfactant,
such as cetyl trimethylammonium bromide (CTAB), may be used to
hydrophobize the surfaces of the silicon-containing core 302. Other
surfactants 304 which may be used with embodiments described herein
include sodium dodecyl sulfate (SDS) and sodium lauryl sulfate
(SLS).
[0034] Since the silicon-containing core 302 is intrinsically
hydrophilic, the surface is partially hydrophobized in order to
favor particle adsorption at the oil/water interface. To achieve
this, the surfactant 304 is employed at a very low concentration,
such as below 1.times.10.sup.-3 mol/L for CTAB. The surfactant 304
is then partially adsorbed on the surface of the silicon-containing
core 302. The surfactant 304 can be selected to obtain the
strongest anchoring of the molecules on the silicon-containing core
302 surfaces.
[0035] Without intending to be bound by theory, it is believed that
the emulsions are rapidly destabilized if the concentration of
surfactant 304 initially introduced is above its critical micellar
concentration (cmc), which is approximately 9.times.10.sup.-4 mol/L
for CTAB. It is well-known that molecules such as CTAB form
bilayers at the silica/water surface when the free surfactant
concentration in the aqueous phase exceeds 1 cmc. The polar heads
of the external layers are oriented toward the water phase, and the
silica surface remains hydrophilic. Under such conditions, the
solid particles do not adsorb on the emulsion droplets and the
behavior is the same as that for surfactant-stabilized emulsions.
As such, a low concentration of the surfactant 304 or other
surfactant is used to avoid the creation of a bilayer at the
surface of the particles. In one embodiment, the silicon-containing
core 302 is exposed to the surfactant 304 at a ratio of surfactant
304 to silicon-containing core 302 of from about 5.times.10.sup.-6
mol L.sup.-1m.sup.-2 to about 2.5.times.10.sup.-6 mol
L.sup.-1m.sup.-2.
[0036] The silicon-containing core, having a first surface and a
second surface, can then be embedded in a lipophilic component of
an emulsion, the silicon-containing core being embedded such that
the first surface is exposed and the second surface is obstructed
by the lipophilic component, at 206. The surfactant 304 and the
partial hydrophobicity it provides, helps promote anchoring of the
silicon-containing core 302 at the oil/water interface. A wax 306
or other lipophilic component can then be added to the suspension.
In one example, the wax 306 added to the suspension is paraffin
wax. The suspension is heated or maintained at a temperature which
will melt the wax 306. Once the wax 306 has melted, the suspension
can then be agitated to assure complete mixture of the
silicon-containing core 302 and the wax 306. In one embodiment, the
suspension is vigorously stirred at between 6,000 rpm and 10,000
rpm for a period of time, such as between about 30 s and about 90
s. The emulsion is then allowed to cool to a temperature such that
the wax solidifies, for example to room temperature. The droplets
of wax 306 with the embedded silicon-containing cores 302 are shown
in FIG. 3C.
[0037] The first surface 308 is then washed to create a clean first
surface, at 208. The boundary of the first surface 308 is defined
by the portion of the silicon-containing core 302 that is embedded
in the wax 306. The silicon-containing core 302 will still have a
portion of the surfactant 304 formed on the first surface 308. As
such, the first surface 308 can be washed using an acid. In one
embodiment, the wax 306 with the silicon-containing core 302 is
then filtered and washed using hydrochloric acid (HCl). After the
wash, the silicon-containing cores 302 have an exposed first
surface 308 while remaining embedded in the wax 306, as shown in
FIG. 3D.
[0038] The clean first surface 308 is then exposed to a
resin-binding functionalizing material 310, at 210. The
resin-binding functionalizing material enables the sizing material
300 to attach to the resin. The resin binding functionalizing
material 310 is a molecule which binds to the silicon-containing
core 302 and creates a surface on the silicon-containing core 302
which can bind a resin. The resin binding functionalizing material
310 provides an anisotropic surface chemistry on the
silicon-containing core 302. For the surface modification of the
particle, the wax 306 with embedded silicon-containing cores 302
can be reacted in their original suspension with the resin binding
functionalizing material 310. The resin binding functionalizing
material 310 can include functional groups such as vinyls, amines,
epoxies, allyls, and acrylates. In one embodiment, the resin
binding functionalizing material 310 is vinyl chloride.
[0039] The lipophilic component can then be removed to expose the
second surface, at 212. After attaching the resin binding
functionalizing material 310, the silicon-containing core 302 is
removed from the wax 306 to expose the second surface 312. To
remove the wax 306, a solvent, such as a hydrocarbon solvent, can
be used. In one embodiment, the solvent is benzene. The
silicon-containing core 302 is then centrifuged and decanted one or
more times to yield silicon-containing core 302 free of the wax
306.
[0040] Then, the second surface can be exposed to a silanizing
agent 314, at 214. The silanizing agent 314 is an organofunctional
alkoxysilane molecule, such as chlorotriethoxysilane. In order to
attach the silicon-containing core 302 to the fibers 112, the
silicon-containing core 302 must be functionalized. This
functionalization is done by reacting silanizing agent 314 with the
exposed particle surface (e.g., the second surface 312). In this
embodiment, the reaction of the silicon-containing core 302 with
the silanizing agent 314 functionalizes the second surface 312
leaving the ethoxy-functionalities available for reaction to the
glass fibers. Since the resin binding functionalizing material 310
is bound to the first surface 308 and does not have an exposed OH
group, the first surface 308 cannot react with the silanizing agent
314.
[0041] The resulting sizing material 300 (also referred to as the
dual-surfaced particle) has two functional regions capable of
binding both the resin (e.g., the resin binding functionalizing
material 310) and the fiber 112 (e.g., the silanizing agent 314).
By creating two functional domains for the sizing material 300, the
sizing material 300 does not need to be removed after the fibers
112 are extruded. This saves both processing time and reduces the
number of steps involved in the creation of fiber based products,
such as printed circuit boards (PCB).
[0042] FIG. 4 depicts a method 400 of forming a board, according to
one embodiment. The method 400 includes extruding a plurality of
glass fibers, at 402; coating at least a portion of a surfaces of
the glass fibers with a sizing material, the sizing material having
an anisotropic surface chemistry with a first exposed region and a
second exposed region, the first exposed region interacting with
the fibers, at 404; forming the plurality of fibers into a
plurality of strands, and spooling the plurality of strands, at
406; weaving a cloth from the plurality of strands, at 408; and
impregnation of the cloth with a resin, at 410.
[0043] The method 400 begins with extruding a plurality of glass
fibers, at 402. The plurality of fibers are extruded in a
substantially similar manner as described with reference to the
fibers 112 of FIG. 1. The fibers can comprise glass, such as fibers
made substantially of glass.
[0044] At least a portion of a surface of the fibers can be coated
with a dual-surfaced particle, at 404. The dual-surfaced particles
have an anisotropic surface chemistry between a first exposed
region and a second exposed region. The dual-surfaced particle can
be substantially similar to the sizing material 300 described with
reference to FIGS. 3A-3H. The first exposed region interacts with
the portion of the surface of the at least one of said fibers. The
second exposed region is silanized, as described with reference to
FIG. 2 and FIGS. 3A-3H.
[0045] The plurality of fibers can then be formed into a plurality
of strands and spooled, at 406. The formation of the strands and
spooling of said strands is substantially similar to the formation
and spooling process generally described with reference to FIG.
1.
[0046] A cloth can then be weaved from the plurality of strands, at
408. The cloth can be formed by weaving the above described
strands. The plurality of strands may be used as the warp or
portions thereof, the filling or portions thereof, or any
combinations thereof. Thus, non-sized strands can be used as the
warp, the filling, or any portion thereof, in conjunction with the
plurality of strands such that a cloth can be made. The plurality
of strands including the dual-surfaced particles described above
can provide protection to and from the non-sized strands.
[0047] After weaving, the cloth can be impregnated with a resin, at
410. The dual-surfaced particles all have a substantially similar
orientation, based on the binding of the silanizing material to the
fibers of the strand. Thus, the dual-surfaced particle is oriented
such that the resin binding functionalizing material is facing
outward from the strand. The cloth, made using said strands, is
then impregnated with the resin, such as by immersion, spray or
other delivery methods. The resin used may be a resin for use in
the formation of fiberglass boards for PCBs. One such resin is an
epoxy resin. Once impregnated with resin, the cloth and resin
composite may be pressurize and cured creating a laminate.
[0048] In this embodiment, the fibers are coated with a sizing
material as described above. The sizing material allows for binding
and protection of the fibers during the extrusion and weaving
processes, without negatively affecting the binding of the resin.
Therefore, removal of the sizing material prior to impregnation is
necessary. Using embodiments described here, the resulting device
can be created with lower energy input, fewer steps and shorter
time to completion than devices made using other methods.
Example
[0049] In one embodiment, the silicon-containing cores of the
sizing material were prepared through a modified Stober synthesis
using anhydrous ethanol (200 proof), ammonia (2M), deionized water,
and tetraethoxysilane (TEOS). (Stober et al., Journal of Colloid
and Interface Science, Vol. 26, pg. 62-69 (1968)) Ethanol (6 mL)
and TEOS (1 mL) were added together and shaken to mix, creating a
monomer solution. In a separate vial, 2M ammonia (4 mL) and
deionized water (1 mL) were added and shaken to mix, creating an
ammoniacal solution. The ammoniacal solution was then poured into
the monomer solution and then left to react. After reaction period,
particles were centrifuged and rinsed with ethanol to remove
residual monomer yielding silica nanoparticles.
[0050] Sizing material with resin bonding functionality was
prepared using a paraffin-in-water emulsion. Silicon-containing
cores were dispersed in an ethanol/water solution and heated to
65.degree. C. creating a suspension. Cetyl trimethylammonium
bromide (CTAB) was then added to the suspension, followed by
paraffin wax (1 g) being deposited on top of the suspension. Once
the wax was melted, the mixture was vigorously stirred (9000 rpm)
for 80 s. The emulsion was then allowed to cool to room temperature
allowing for the droplets of paraffin wax with embedded silica
particles to solidify. The solid paraffin wax droplets were then
filtered and dispersed into toluene (20 mL) and stirred. Next,
vinyl chloride (0.1-10 wt %) was added and the mixture is heated to
35.degree. C. The mixture was allowed to react for 48 h followed by
filtration and washing of the wax droplets with ethanol. Finally,
the paraffin droplets were dissolved in dichloromethane (DCM) to
produce sizing material with resin-bonding functionality.
[0051] To prepare the dual surfaced particle, toluene (20 mL) was
added to a separate flask and was stirred. To the toluene, 1 g of
the sizing material with resin bonding functionality was added,
followed by the dropwise addition of chlorotriethyoxysilane (0.1-10
wt %). The particle mixture was then allowed to react for 24 h at
35.degree. C. After reaction, the mixture was cooled to room
temperature and then filtered and washed with ethanol. The final
product was then dried under a vacuum.
[0052] Molten glass was extruded into individual fibers. The fibers
were then sprayed or dipped into a solution containing the
dual-surfaced particle (0.1-10 wt %, ethanol, and acetic acid).
After treatment of the glass fibers, the fibers were then dried.
Next, the finished "particle sized" fibers were formed then into
strands (or yarn). The strands were then woven into glass cloth.
Since the "particle sizing material" has the organic
functionalities (i.e., epoxies, amines, vinyls, allyls, acrylates)
already attached, the newly formed glass cloth can be impregnated
with resin and then used for laminates.
[0053] Embodiments described herein relate to devices, systems and
methods for the formation of fibers using a sizing material
comprising a dual-surfaced particle. The fibers are coated with a
sizing material and the dual-surfaced particles bind to the fibers
as described above. From here, the fibers can be converted to
threads, woven into fabrics and otherwise processed without removal
of the sizing material. Since the sizing material allows for
binding and protection of the fibers without negatively affecting
the binding of the resin, no removal step is necessary. Thus, the
resulting circuit board substrate can be created with lower energy
input, fewer steps and shorter time to completion than circuit
board substrates made using other methods.
[0054] While the foregoing is directed to embodiments of the
present devices, systems and methods, other and further embodiments
of the devices, systems and methods may be devised without
departing from the basic scope thereof, and the scope thereof is
determined by the claims that follow.
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