Note: Descriptions are shown in the official language in which they were submitted.
CA 02679778 2009-09-22
TITLE OF THE INVENTION
Fiberglass Reinforced Plastic Products Having
Increased Weatherability, System and Method
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent application
serial number
11/881,591 filed July 27, 2007, which is a continuation-in-part of U.S. patent
application serial
number 11/699,254 filed January 29, 2007, which claims priority from U.S.
provisional
application serial number 60/775,304 filed February 21, 2006.
FIELD OF THE INVENTION
100021 The present invention relates to the pultrusion of rail. More
specifically, the
present invention relates to the pultrusion of rail using resin without filler
to increase the
weatherability of the rail.
BACKGROUND OF THE INVENTION
[0003] Fiberglass reinforced plastic ladder rails are traditionally produced
by the
pultrusion process. In this process, reinforcements are gathered
systematically, impregnated with
a cureable resin, formed into a shape and cured continuously by the addition
of heat in a metallic
die. The process has been in existence for over fifty years with little change
in the basics design
of the process. During the past ten years, the federal government has through
the Environmental
Protection Agency and through Air Quality Standards caused the operators of
the pultrusion
process to reassess the methods they use to handle VOC containing resins in
the pultrusion
process. This has evolved several different methodologies for impregnating
reinforcement that
minimize the contact of the impregnating resin with the atmosphere and also
reducing the
exposure of workers to the volatile chemicals.
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BRIEF SUMMARY OF THE INVENTION
100041 The present invention pertains to climbing products containing rails
decorated
using veil products colored, patterned, painted or in combination with marking
methods such as
company names and logos and resin formulation designed to withstand exposure
to UV radiation
with minimal change in appearance which create specific appearances for
applications, enhance
weathering performance, and facilitate processing efficiency.
[0005) The present invention pertains to a combination of a filler free resin
and coated
veil systems to create a synergistic weather resistance surface with self
contained color, pattern,
picture, logo or combination of said same for climbing products. Resins can be
generically of
polyester, acrylic, epoxy, urethane, acrylate, and or combinations of said
resins. Veils may dyed,
printed, pigmented, transfer coated or combinations of said methods familiar
to one skilled in the
state of the art. Veil compositions may be glass, polyester, paper, jute or
other dispersed fiber
systems capable of maintaining mechanical and dimensional performance
throughout the ladder
section production process.
[0006] The present invention pertains to a method for continuously placing
specific
amounts of internal structural resin into a product by balancing the volume
flow of input internal
structural resin in an enclosed impregnation system to the size of the product
and the line speed
of the manufacture process.
[0007] The present invention pertains to the use of a central reinforcement to
carry
structural resin and maintain distribution of structural resin through the
impregnation process to
the curing die.
[0008] The present invention pertains to the use of specific reinforcement
systems and
impregnation processes to self limit the amount of structural resin introduced
into a laminate
during the impregnation process by using the absorptivity and compression
characteristic of the
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internal reinforcement to carry said resin through the process and transfer
said resin to adjacent
unwet structural layers prior to the curing process of the resin in the
manufacturing process.
[0009] The present invention pertains to a method for changing part color
without
stopping production which minimizes total raw material lost and product lost
to mixed
appearance.
[0010] The present invention pertains to a method of folding veils such that
the
crossovers between veils are located and controlled at a prescribed positions
on the part.
[0011] The present invention pertains to a method for continuously producing
on
separate streams of a single machine colored parts of differing color.
100121 The present invention pertains to a method for continuously producing
parts with
differing colors in controlled positions around the perimeter of the said
parts.
100131 The present invention pertains to a method for continuously producing
on
separate streams of a single machine colored parts of differing color while
continuously
producing parts with differing colors in controlled positions around the
perimeter of the said
parts.
100141 The present invention pertains to a system for producing components.
The
system comprises means for producing rail having a delta E less than 20 with a
60 degree gloss,
as measured by a 100 gloss meter, of greater than 70 after 1000 hours of
accelerated weathering
in a QUV chamber using bulb A with an ASTM cycle. The system comprises means
for cutting
the rail.
[0015] The present invention pertains to a ladder rail. The rail comprises a
web. The rail
comprises a first flange extending from the web. The rail comprises a second
flange extending
from the web. The web and first and second flanges made of fiberglass and
resin and together
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forming the rail having a delta E less than 20 with a 60 degree gloss, as
measured by a 100 gloss
meter, of greater than 70 after 1000 hours of accelerated weathering in a QUV
chamber using
bulb A with an ASTM G154 cycle 4.
100161 The present invention pertains to a method for producing components.
The
method comprises the steps of producing rail having a delta E less than 20
with a 60 degree
gloss, as measured by a 100 gloss meter, of greater than 70 after 1000 hours
of accelerated
weathering in a QUV chamber using bulb A with an ASTM G154 cycle 4. There is
the step of
cutting the rail.
100171 The present invention pertains to a system for producing a ladder rail.
The system
comprises a pultrusion system. The pultrusion system comprises a prewet which
wets a middle
mat with a resin and filler. The pultrusion system comprises an impregnator
which compresses a
first veil outer layer, a second veil outer layer, a first mat layer, a second
mat layer, a first roving
layer and a second roving layer with the middle mat, and which wets only the
first veil outer
layer, the second veil outer layer, the first mat layer and the second mat
layer with resin without
filler.
[0018] The present invention pertains to a ladder rail. The rail comprises a
first veil
layer. The rail comprises a first mat layer having a first color in contact
with the first veil layer.
The rail comprises a first roving layer in contact with the first mat layer.
The rail comprises a
middle mat layer in contact with the first roving layer. The rail comprises a
second roving layer
in contact with the middle mat and together the middle mat and first roving
layer having a
second color. The rail comprises a second mat layer having the first color in
contact with the
second roving layer. The rail comprises a second veil layer in contact with
the second mat layer.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0019] In the accompanying drawings, the preferred embodiment of the invention
and
preferred methods of practicing the invention are illustrated in which:
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[0020] Figure l is a schematic diagram of the pultrusion process.
100211 Figure 2 shows a section of a pultruded profile.
[0022) Figure 3 is a schematic of the basic pultrusion process.
100231 Figure 4 shows the relative thickness of the layers of pultruded
section.
[0024] Figure 5 shows a seven layer laminate.
[0025] Figure 6 shows through a three layer laminate.
100261 Figure 7 shows a side view of the pultrusion piece.
100271 Figure 8a shows a preform injection design.
[0028] Figure 8b shows a graph of the pressure in the weir versus the pressure
along
taper in impregnation section.
100291 Figure 9 shows a schematic of the controller impregnation.
100301 Figure 10 shows section C of figure 9.
[0031] Figure 11 shows section B of figure 9.
100321 Figure 12 shows section A of figure 9.
[0033] Figure 13 shows a prewet station.
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100341 Figure 14 shows a bottom view of the internal top half of the prewet
station.
[0035] Figure 15 shows a top view of the internal bottom half of the prewet
station.
[0036] Figure 16 shows a side sectional view of the pre-wet station.
100371 Figure 17 shows a front view of the slot where Q is greater than R.
100381 Figure 18 shows a front view of the slot where Q is much greater than
R.
100391 Figure 19 shows a front view of the slot where Q equals R.
[0040] Figure 20 is a front view of a prewet station with a variable slot
version.
100421 Figure 21 is a side view of a prewet station with a variable slot
version.
100431 Figure 22 is a perspective front view of a continuous former.
[0044] Figure 23 is a perspective back view of the continuous former.
[0045] Figure 24 is a graph of the prewet resin versus the pump capacity.
[0046] Figure 25 shows a climbing product of the present invention.
100471 Figures 26 and 27 are photographs of portions of ladder rails with
graphics.
DETAILED DESCRIPTION OF THE INVENTION
[0048] Referring now to the drawings wherein like reference numerals refer to
similar or
identical parts throughout the several views, and more specifically to figure
25 thereof, there is
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shown climbing products 55 containing rails 16 decorated using veil products
colored, patterned,
painted or in combination with marking methods such as company names and logos
or graphics
and resin 14 formulation designed to withstand exposure to UV radiation with
minimal change in
appearance which create specific appearances for applications, enhance
weathering performance,
and facilitate processing efficiency. A logo and/or a picture is part of the
veil itself. The
graphics can also include patterns, artwork replications , photographic
images, and blends of
transitional colors in the veil.
[0049] The present invention pertains to a combination of a filler free resin
14 and coated
veil systems 10 having graphics to create a synergistic weather resistance
surface with self
contained color, pattern, picture, logo or combination of said same for
climbing products. Resins
14 can be generically of polyester, acrylic, epoxy, urethane, acrylate, and or
combinations of said
resins 14. Veils may dyed, printed, pigmented, transfer coated or combinations
of said methods
familiar to one skilled in the state of the art. Veil compositions may be
glass, polyester, paper,
jute or other dispersed fiber systems capable of maintaining mechanical and
dimensional
performance throughout the ladder section 52 production process. Preferably,
when graphics are
used with the veil, a combination of a resin having filler levels below 20
pph, and more
preferably between 5 pph and 20 pph, is used with a coated veil system to
create a synergistic
weather resistance ladder rail surface with graphics.
[0050] The present invention pertains to a method for continuously placing
specific
amounts of internal structural resin 14 into a product having veil with
graphics by'balancing the
volume flow of input internal structural resin 14 in an enclosed impregnation
system 10 to the
size of the product and the line speed of the manufacture process.
[00511 Preferably, there is an enclosure design, such as an injection die that
continuously
distributes the resin 14 in planned uniform or non-uniform volume across the
width of the part 40
to match the volume of reinforcement in the specific locations throughout the
cross section of the
part 40.
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100521 The present invention pertains to the use of a central reinforcement to
carry
structural resin 14 and maintain distribution of structural resin 14 through
the impregnation
process to the curing die.
100531 The present invention pertains to the use of specific reinforcement
systems 10 and
impregnation processes to self limit the amount of structural resin 14
introduced into a laminate
during the impregnation process by using the absorptivity and compression
characteristic of the
internal reinforcement to carry said resin 14 through the process and transfer
said resin 14 to
adjacent non-impregnated structural layers prior to the curing process of the
resin 14 in the
manufacturing process.
[0054] Preferably, the method insures placement of said resin 14 such that the
surface
resin 14 and any structural resins 14 do not intermix yet co-cure to a
laminate whose structural
and functional properties are sufficient for use in climbing
products.(ladders)
[0055] The present invention pertains to a method for changing part 40 color
without
stopping production which minimizes total raw material lost and product lost
to mixed
appearance.
100561 Preferably, the color is changed by introducing veils of differing
color around the
perimeter of the part 40. Preferably, said veils are introduced without
attaching said veils to the
veils of the previous color(s) in the process.
100571 The present invention pertains to a method of folding veils such that
the
crossovers between veils are located and controlled at prescribed positions on
the part 40.
[0058] The present invention pertains to a method for continuously producing
on
separate streams of a single machine colored parts 40 of differing color.
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[0059] The present invention pertains to a method for continuously producing
parts 40
with differing colors in controlled positions around the perimeter of the said
parts 40.
[0060] The present invention pertains to a method for continuously producing
on
separate streams of a single machine colored parts 40 of differing color while
continuously
producing parts 40 with differing colors in controlled positions around the
perimeter of the said
parts 40.
[0061] The present invention pertains to a system 10 for producing components.
The
system 10 comprises means for producing rail 16 having graphics having a delta
E less than 20
with a 60 degree gloss, as measured by a hunter gloss meter, of greater than
70 after 1000 hours
of accelerated weathering in a QUV chamber using bulb A with an ASTM cycle.
The system 10
comprises means for cutting the rail 16.
[0062] The present invention pertains to a ladder rail 16. The rail 16
comprises a web 18
having a graphic. The rail 16 comprises a first flange 20 extending from the
web 18. The rail 16
comprises a second flange 22 extending from the web 18. The web 18 and first
and second
flanges 20, 22 made of fiberglass and resin 14 and together forming the rail
16 having a delta E
less than 20 with a 60 degree gloss, as measured by a hunter gloss meter, of
greater than 70 after
1000 hours of accelerated weathering in a QUV chamber using bulb A with an
ASTM G154
cycle 4.
[0063] The present invention pertains to a method for producing components.
The
method comprises the steps of producing rail 16 having graphics having a delta
E less than 20
with a 60 degree gloss, as measured by a hunter gloss meter, of greater than
70 after 1000 hours
of accelerated weathering in a QUV chamber using bulb A with an ASTM G154
cycle 4. There
is the step of cutting the rail 16.
[0064] The present invention pertains to a system 10 for producing a ladder
rail 16. The
system 10 comprises a pultrusion system 10. The pultrusion system 10 comprises
a prewet 24
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which wets a middle mat with a resin 14 and filler. The pultrusion system 10
comprises an
impregnator 26 which compresses a first veil outer layer 12, a second veil
outer layer 28, a first
mat layer 30, a second mat layer 32, a first roving layer 34 and a second
roving layer 36 with the
middle mat, and which wets only the first veil outer layer 12, the second veil
outer layer 28, the
first mat layer 30 and the second mat layer 32 with resin 14 without filler.
[0065] The resin 14 in the prewet 24 can be the same or different, i.e.,
color, from the
resin 14 in the impregnator 26.
100661 Preferably, the first and second veil outer layers contain all the
colorant needed to
color the ladder rail 16. Preferably, the first and second outer veil layers
combined with the resin
14 without filler form a corrosion and weathering barrier such that said
ladder rail 16 maintains a
delta E of less than 20 and 60 degree gloss of 60 after exposure to 1000 hr of
ASTM G154 Cycle
4 irradiation in a QUV accelerated weathering machine.
[0067] The first and second outer veil layers can contain more than one color.
The first
and second outer veil layers can contain pictures and printed letters or words
and/or graphics.
[0068] The present invention pertains to a ladder rail 16. The rail 16
comprises a first
veil layer having graphics. The rail 16 comprises a first mat layer 30 having
a first color in
contact with the first veil layer. The rail 16 comprises a first roving layer
34 in contact with the
first mat layer 30. The rail 16 comprises a middle mat layer 38 in contact
with the first roving
layer 34. The rail 16 comprises a second roving layer 36 in contact with the
middle mat and
together the middle mat and first roving layer 34 having a second color. The
rail 16 comprises a
second mat layer 32 having the first color in contact with the second roving
layer 36. The rail 16
comprises a second veil layer in contact with the second mat layer 32.
[0069] Preferably, the first mat layer 30, and the second mat layer 32 having
resin 14
without filler; and the first and second roving layers 34, 36 and the middle
mat layer 38 having
resin 14 with filler.
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100701 In the operation of the invention, colored veil offers a low cost
approach for
meeting commercial objectives of improved fiberglass product performance,
particularly that of
weathering characteristics.
100711 Colored veil advantages relative to ladder and climbing products that
use
reinforced fiberglass plastic (FRP) components are centered on improved
weather resistance and
the reduction of manufacturing change-over costs from color to color with
traditional pigmented
resin 14 processes. An un-colored, unfilled clear resin system 10 is used
together with pre-
colored veil to produce the composite component in substitution for color-
pigmented resin 14
with un-colored veil.
[0072] Manufacturing equipment and tooling configurations that provide
separate resin
14 delivery to the periphery of the composite's cross section and to the cross
section's interior is
utilized to:
100731 1. Improve weathering characteristics by using higher performance resin
14
formulation on the component's exterior.
[0074] 2. Lowered cost by using standard resin 14 formulations in the interior
cross
sectional area and reductions in manufacturing change-over time and associated
material scrap.
[0075] 3. Flexible manufacturing for prototype samples, marketing promotions,
and
special orders.
[0076] 4. Eff ciencies of demand balance of production lines where a
production
machine can pultrude composite streams in different, separate colors
simultaneously, rather than
limited to a single color from a common pigmented resin 14 bath supply.
[0077] 5. Pre-colored and pre-printed veil allows introduction of graphics,
patterns,
color combinations, logos, and brand names into the product's appearance.
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[0078] Process description
[0079] The methods are generically some form of closed or partially closed
impregnation
bath or die run at either ambient or elevated pressure. These "injection" dies
have been disclosed
in various patent literature (see US Patent 6,048,427 by Gauchel et. al.; US
Patent 5,783,013 by
Beckman and Gauchel; US Patent 5,747,075 by Gauchel et. al.; US Patent
5,322,582 by Davies
et. Al.; and US Patent 3,684,622 by Goldsworthy; all of which are incorporated
by reference
herein, and which describe Pultrusion). Each of these patents teaches methods
for placing resin
14 or resins 14 into or uniformly through the part's 40 cross section. Davies
discusses using
discrete roving packets to selectively place a second resin 14 locally within
a part 40. Gauchel
and Beckman discuss methods for selectively impregnating various parts 40 of
the reinforcement
package by either separate die technology of separate weir 42 technology.
Goldsworthy uses
multiple impregnation ports and internal injection systems to place resin 14
into the
reinforcement pack. In all cases no attempt is made to insure that the
multiple resins 14 are
maintained in discrete layers through the thickness of part 40 along the
length of the part 40.
[0080] In this invention, the teachings referenced above are improved by
creating mass
flow conditions which cause multiple resins 14 to remain in specific areas
within the part 40
(placement of resin 14 is accomplished by contacting resins 14 with selected
reinforcements in
the stacking sequence (donor layers) of the part 40, i.e. the middle mat,
supplying the resin 14 at
a known rate sufficient to remove the air from the reinforcement when it is
compressed and
compressing the reinforcement to a given thickness distribution along the
width of the mat. For
samples of constant cross section and glass content the impregnated
reinforcement would be
compression uniformly across the width. The degree of compaction is determined
mathematically by calculating the amount of resin 14 needed to fully saturate
the reinforcement
at the thickness it will be compacted to in the final part 40 plus the amount
of resin 14 needed to
transfer from the preimpregnated mat to the adjacent layers (acceptor layers).
This amount is
determined from the amount of glass in the acceptor layers and the final
thickness of the acceptor
layers in the cured part 40. (All glass roving layers are optimally
impregnated with standard
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density resin 14 at a weight percent of approximately 75%. Glass Mat layers
compacted to their
final thickness in the die are fully saturated at about 35% by weight.)
[0081] Transfer to the acceptor layer is only accomplished as the reinforcing
pack is
compressed in the forming process prior to introduction of the topcoat in the
injection die. The
design of the forming station and impregnation die is such that the
reinforcement pack is
compressed to within 0-5 mils of the thickness of the part 40 in the curing
die prior to addition of
the second resin 14.
[0082] If more than two resins 14 are used, the thickness would be compressed
such that
layers to be impregnated by the first resin and the donor layer of the second
resin are compressed
to a calculated thickness such that the first layer and its receptor layers
are impregnated with the
initial resin 14 and the second donor layer is compressed to the proper
thickness to accept the
proper amount of resin 14 to impregnate itself plus its acceptor layers. The
process is repeated
depending on the number of resins 14 that are being introduced to the part 40.
100831 Along with process improvement, a materials modification of using a
combination of surfacing veil to which has been added dies/pigments/paints to
selectively or
uniformly color the part's 40 exterior and a resin 14 formula designed from
resin 14 types known
to have the combination of weathering performance and processing capability in
the pultrusion
process and additive packages which minimize degradation of the resin 14 on
weathering and
placing said resin 14 a veil on the exterior of the part 40 to create a part
40 with weathering
characteristics superior(as measured by change in appearance - gloss and color
change (delta E
value from spectrophotometer)- after exposure to known quantities of light in
a QUV-accelerated
weathering apparatus to the current state of the art for materials produced
from the pultrusion
process.
[0084] While modified surfacing veils have been used to develop functional
characteristics in pultruded parts, they have not be used with high
performance unfilled resins 14.
The reason was that to use the high performance resins 14 throughout the part
thickness was not
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cost effective. But if the modified veil and high performance resins 14 are
used with the process
modifications of this invention, only a thin layer of high performance resin
14 needs to be used
to create a functionally weathering layer, see above description of resin 14
placement method.
Because this invention allows varying the thickness of the layer of
reinforcement available for
impregnation by the clear outside corrosion resin 14 by either selection of
the thickness of the
outside reinforcement and/or control of the amount of inside resin(s) 14
placed on the donor
layer(s) of the part 40, a cost effective laminate may be obtained which has
better measurable
response to accelerated weathering while maintaining the needed structural
performance for
climbing products as measured by performance in ANSI14.5 testing protocols,
incorporated by
reference herein.
[0085] Other aspects of this invention relate to the synergy between the use
of colored
veil, selective resin 14 placement and process techniques. These interactions
create
improvements in scheduling flexibility, product diversity and manufacturing
efficiencies which
lead to increased productivity. One example of the improvement in process
scheduling that
occurs when parts 40 of varying color can be run simultaneously on one
machine. Currently all
streams on a given pultruder run parts 40 with the same color resin 14
supplied to each stream
from a single holding tank-excess resin 14 is collected and recycled to the
input holding tank
and reused. To run individual steams with different color resin 14 multiple
holding pots with
separate pumps and resin 14 recycle hardware would be required. Not only would
this be
expensive but because of the limited space on the machine difficult and
cumbersome to the
operator. Introducing colored veil allows the existing hardware to be used
because only non-
colored resins 14 are required. Each stream on a multi-steam machine is
capable of running its
own color as determined by the color of this input veil used in the part 40.
100861 Likewise products with multicolors, patterns or pictures can be
produced using
the appropriate incoming veil manufactured by standard veil printing and dying
techniques to
colors which when put through the rail 16 making process produce colors that
are selected to
match standards desired by marketing for specific ladders-example a deep blue
for the
electricians ladder actually starts with a veil whose color appears to be too
red and too purple to
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create the desired color. Color shifts through the process are determined
experimentally and
vary by color.
[00871 Changing colors also becomes extremely easy. Changing standard veils is
commonly done during processing. The veils are allowed to run out in a random
manner and are
replaced as needed. This can be done on the fly with little or no scrap and no
down time. With
colored veils the only modification is that if a color change is occurring all
veils on the part 40
need to be changed within a small distance of each other to minimize scrap do
to multicolored
parts 40. Otherwise, no shutdown for cleaning or transfer of one colored resin
14 out of the
system 10 and placement of the new color into system 10 is required - no scrap
or unused resin
14 - no loss of productivity while the resin 14 change occurs- no mess
associated with cleaning
guides 48 and resin 14 return pans etc.
100881 With proper guidance methods, veils do not even require attachment
between
ends of preceding and subsequent veils, thus eliminating more work for the
machine operator.
[0089] If entire operations are converted to this process, other synergies
occur in the
mixing and resin 14 delivery systems which further improve the cost
effectiveness of the
product. One topcoat and one structural resin 14 formula can be used for all
colors and shapes
with the colored veil process we would have only one prewet 24 formula and one
topcoat
formula for all colors and locations. The mix room would make prewet 24 and
topcoat only not
multiples of each. Thus, knowing the relative requirements of each resin 14
for each part 40,
resin 14 mixing volumes may be optimized so that minimal excess of any resin
14 is obtained
during the mixing operation. All topcoats are equal and can be sent to any
line. Likewise, all
structural resin 14 batches are the same and can be utilized by every machine.
No more having
too much blue and not enough yellow to meet a varying demand. Color is now
dependant on
long term stable veils systems capable of being inventoried without fear of
loss by reaction.
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[0090] Cleanup between color changes is virtually eliminated. Preventive
maintenance
on lines and pumps replaces requirements for purging systems with solvent and
unpigmented
resins 14 to clean lines in order to run a light color after a dark one.
[0091] Running colored or printed veils requires ungrading the quality of
reinforcement
placement during the pultrusion process. Veil placement must be maintained
constant so that any
overlaps occur in the proper location. The upside of the placement issue is
that with proper
placement techniques veils no longer need to be as wide. Current veils are
extra wide to take
into account lateral shrinkage and to make sure there is a bunching of veil at
the tips of flanges.
This means that the standard veils are between .5 and 1.0 wider than need to
cover the perimeter
of the part 40. Colored veils shrink less during the process and the placement
is more consistent
because a veiless surface cannot be allowed to occur. Bunching is also not
wanted on the tipps
with colored veil because it causes the tips to be a different color than the
rest of the part 40. The
consistent placement is created with an added veil folding device(s) which
allow the veil to fold
only one way. Reducing veil width creates a measurable materials savings.
[0092] In regard to weathering cycle, see ASTMG154 Cycle 4, incorporated by
reference
herein. Relative weathering performance for yellow part
[0093] 1. Previous standard overcoat Delta E =40 1000 hrs QUV
[0094] 2. Standard Through color /RI =35
[0095] 3. Colored veil with stand resin =35
100961 4. Colored veil with no filler resin =12
[0097] (the present invention)
100981 1000 hrs QUV = 1 year south Florida for the cycle we are using
[0099] Delta E above 20 is cut off for acceptable performance
[0100] Processing with colored veil takes color change from multiple hours to
about a
minute
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[0101] Colored veil allows different colors on same machine simultaneously
[0102] Colored veil allows different colors on same part. The gloss of the
rail 16 is
greater than 70.
[0103] Definitions
[0104] Donor layer: A layer of reinforcement(s): the donor layer may consist
of
multiple reinforcements such as mat plus roving or multiple
mats but is normally a single mat that is impregnated
directly with resin 14 in an uncompressed or partially
compressed state such that the amount of resin 14
transferred to the layer is sufficient to fully impregnate
itself plus impregnate the acceptor layer(s) adjacent to it in
the cured laminate. The characteristics of a donor layer are
that it is uniformly compressible, compressibility versus
pressure is known and reproducible, structure is such that it
can accept and give up resin 14 easily as compressed, and
that its structure is such that it will maintain a non uniform
resin 14 distribution over the time frame of the
impregnation, combination and forming processes so that a
distributed resin 14 volume may be transferred to the
acceptor layers.
101051 Acceptor layer: A layer of reinforcement usually roving which is put
into
the combination and fonming process in an unimpregnated
or partially impregnated state. Impregnation of the
acceptor level occurs as it is combined with a donor layer
and the donor layer/acceptor layer(s) package is
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CA 02679778 2009-09-22
compressed in the forming and final impregnation stations
of the process.
[0106] Combination process: A segment of the total pultrusion process that
brings layers
of reinforcement together into a reinforcement package.
The combination process normally is placement only with
little or no compaction of the layers.
[0107] Forming process: A segment of the total pultrusion process that takes
the
fully combined reinforcement package (including
impregnated donor layers) and shapes them from a flat or
slightly curves shape to a shape similar to the shape of the
curing die but slightly larger in all dimension.
[0108] Final Impregnation Process: A segment of the total pultrusion process
that compacts the
reinforcement package causing the donor layers to release
resin 14 to the acceptor layers and brings the reinforcing
package to the size of the curing die, and simultaneously
adds topcoat resin 14 under pressure and removes and
remaining air from the reinforcement package. This results
in a fully impregnated reinforcement package with donor
resin 14 distributed throughout the donor acceptor layers
and topcoat resin 14 distributed in the outside topcoat
containment layers (normally this would be the veil and the
outside mat layers of our standard seven layer laminate, but
we could use other types of reinforcements under the veil to
contain the topcoat resin 14)
[0109] PULTRUSION PROCESS
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CA 02679778 2009-09-22
[01101 Sizing the opening in the prewet 24 die
[0111] 1. What is the arnount of resin 14 required to fully saturate a layer
of given
thickness for common pultrusion reinforcernents?
[01121 Requires knowing the volume occupied by the reinforcement layer
in a cured pultrusion laminate
[0113] Reinforcement Type Thickness in Pultruded laminate (in)
101141 1 oz continuous filament mat .020
[0115] .625 oz Holinee Madiglioni Mat .020
[0116] .75 oz continous filament Mat .017
[0117] uniform layer of roving (250 yield) .0224
[0118] and it also requires knowing the percentage of the reinforcement
layer the reinforcement actual occupies (the rest is occupied by the
resin 14)
[0119] Equilibrium Glass Volume fraction
In pultruded layer
101201 1 oz continuous filament mat .23
(0121] .625 oz Holinee Madiglioni Mat .151
[0122] uniform layer of roving (250 yield) .60
101231 One then can calculate the split in thickness between reinforcement and
resin 14.
101241 Thickness occupied by reinforcement
[01251 And resin 14 in pultruded layer
(01261 Reinforcement (in) Resin(in)
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CA 02679778 2009-09-22
[0127] 1 oz continuous filament mat .0046 .0154
[0128] .625 oz Holinee Madiglioni Mat .0031 .0169
[0129] uniform layer of roving (250 yield) .00134 .009
101301 2. From the above data one can now size the preimpregnation station
exit slot
50. If a .625 Holinee mat is used as a donor layer for two acceptor layers
of 250 roving, the Holinee mat must contain on exit of the
preimpregnation chamber enough resin 14 to fully saturate all three layers.
This would be .0154 in of resin 14 for the mat itself plus .018 in of resin
14 for the roving layers (2 x .009). Thus, the total thickness of the mat on
exit of preimpregnation chamber should be .0031 for the glass in the mat +
.0334 for the resin 14 = .0364 inches. Since Holinee mat in the
unimpregnated state is .079, the mat will accept and hold this amount of
resin 14 with minimal transfer of resin 14 during the combination and
forming process. Only when compaction of the mat to less than a
thickness of .0364 inch will resin 14 transfer from the donor mat to the
acceptor rovings. Formers 46 are designed with a 1.5 factor on all
dimensions so that the thickness available in the former 46 for a holinee
layer is .020 x 1.5 = 0.0300. Thus, thirty-three percent of the total
transfer to the acceptor roving takes place prior to the final impregnation
chamber.
[0131] Composition for Best practice for this invention:
[0132] 1. Use of .625 oz/sq ft Holinee mat as central donor.
[0133] 2. Use of 2 1 oz/ sq ft Continuous Filament Mats (from either OC or
CSG) as
Outside structural layers
[0134] 3. Use of 2 layers of continuous roving (250 yd/lb yield -multiple
sources)
placed such that each layer contains 11 rovings per linear inch of width
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CA 02679778 2009-09-22
[0135] 4. Use of 2 layers of dyed polyester veil from Precision Fabrics
Group(PRG)
each layer weighs 1.65-2.5 oz/square yd. depending on color. For orange
a weight of 1.75 oz/yd gave the best compromise of initial color and
retention on weathering.
101361 5. Prewet 24 formulation based on AOC P 920-300 DCPD end capped
polyester resin 14 with 18-25 pphr fillers such as kaolin clay, calcium
carbonate or combinations of calcium carbonate and clay; [The most used
mixture is 14.25 pphr of Wilklay SA-1 kaolin clay and 14.25 pphr of
Hubercarb W3 calcium carbonate] lpphr of internal release[ Axel IntPul
24] and .9 part of peroxide initiator(s) [we use three initiators -- a low
temperature, mid temperature and high temperature combination (luperox
223V75, tertiary amyl peroxyethylhexanote, and
tertiarybutylperoxybenzoate) in a 6:2:1 ratio].
[0137] 6. A topcoat resin 14 with the same ingredients and ratios except the
fillers
are removed.
[0138] Holinee mat is pulled through a prewet 24 station with an exit slot 50
width of
.036+/- .003 inches. The prewet 24 station is supplied with sufficient resin
14 such that the
reservoir within the prewet 24 station remains full and resin 14 does not exit
the input slot 50
where the mat enters the prewet 24 station. This input flow is determined for
each prewet 24
station from calibration runs of Mass flow versus flow setting, the size of
the part 40 and the
amount of resin 14 being transferred to the donor layer.
101391 Calibration method:
[01401 1. Weigh 3 containers
[0141] 2. Set flow gage on prewet 24 pump to setting A
101421 3. Pump resin 14 into Container for 2 minutes
[0143] 4. Reweigh container and calculate mass flow (weight/min)
[0144] 5. Repeat step 2-4 for settings B and C
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CA 02679778 2009-09-22
[0145] 6. Using results, plot chart of mass flow versus setting for particular
pump/
prewet 24 station combination
[0146] 7. Using chart and weight requirements for donor layer select setting
for
prewet 24 pump which is balanced to output requirement.
[0147] Referring to figure 1, the pultrusion process, very similar to
extrusion, is the only
continuous process for the production of composite profiles. In pultrusion,
reinforcing materials
(glass, Kevlar or carbon fibers) in the fonn of continuous rovings, mats and
other types of
fabrics, are pulled through a resin 14 matrix bath or other impregnation
device, then carefully
guided through a pre-shaping station followed by a heated, high precision, die
in which the resin
14 matrix sets at high temperature to form the final product. Finally, the
hardened profile is
continuously pulled past a saw, activated to cut it into pre-determined
lengths.
[0148] Pultruded composites
[0149] A pultruded composite is generally made up of reinforcing materials
(glass,
Kevlar, carbon fibres) held together by a rigid resin 14 matrix (polyester,
vinylester, epoxy
thermosetting resin 14). Often, surface veils are incorporated to improve
weathering and
corrosion resistance.
[0150] Figure 2 shows a typical section 52 of a pultruded profile for general
use.
[0151] While pultrusion machine design varies with part 40 geometry, the basic
pultrusion process concept is described in Figure 3.
[01521 The creels position the reinforcements for subsequent feeding into the
guides 48.
The reinforcement must be located properly within the composite and controlled
by the
reinforcement guides 48.
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CA 02679778 2009-09-22
[0153] The resin 14 impregnator 26 saturates (wets out) the reinforcement with
a solution
containing the resin 14, fillers, pigment, and catalyst plus any other
additives required. The
interior of the resin 14 impregnator 26 is carefully designed to optimize the
"wet-out" (complete
saturation) of the reinforcements.
[01541 On exiting the resin 14 impregnator 26, the reinforcements are
organized and
positioned for the eventual placement within the cross section form by the
preformer. The
preformer is an array of tooling which squeezes away excess resin 14 as the
product is moving
forward and gently shapes the materials prior to entering the die. In the die
the thermosetting
reaction is heat activated (energy is primarily supplied electrically) and the
composite is cured
(hardened).
[0155] On exiting the die, the cured profile is pulled to the saw for cutting
to length. It is
necessary to cool the hot part 40 before it is gripped by the pull block (made
of durable urethane
foam) to prevent cracking and/or deformation by the pull blocks. Two distinct
pulling systems
are used: a caterpillar counter-rotating type and a hand-over-hand
reciprocating type.
101561 The entire part 40 of the invention that is being described takes place
from the
exit of the guide plate to the entrance of the curing die. The rest of the
pultrusion process is
essentially unchanged.
101571 Figure 4 shows the relative thickness of the various layers of the
pultrusion. The
outer layer is formed of the colored veil which is thinner relative to the
inner layers. As an
example, the thickness of the colored veil layer is about .005 inches.
101581 Figure 5 shows a cross-section of a seven layer laminate. The
impregnated outer
mat layers will take on the combined color (appearance of the glass
composition and of the filler
resin 14). The central roving mat roving layer takes on the color of the
filler resin 14, which can
be off white. The veils are the color they are dyed.
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CA 02679778 2009-09-22
[0159] Figure 6 is a cross-section of a three layer laminate. The colored veil
outer layers
can have the color they are dyed, while the mat layer in contact with the
outer veil layer can be
slightly green. The inner rovings and mat layers are saturated with filler
resin 14 and can be
white. The colored veil and mat layers are typically .024 - .030 inches thick
while the inner
rovings and mat layers are typically .065 - .070 inches thick. The overall
thickness of the
laminate is typically between .113 -.130 inches thick. The formed laminate of
figure 6 is shown
in figure 7.
101601 Referring to figures 8a and 8b, they are a schematic of a generalized
injection die
with resin 14 overflow return lines. The objective of the impregnation die is
to finish the
impregnation of the reinforcement pack started by the prewet 24. In order to
do this the
impregnation die is designed with a slight taper. The taper compacts the
reinforcement pack such
that the prewet 24 resin 14 in the donor mat is transferred to the acceptor
layers of the
reinforcement pack while leaving the outer layers (mat and colored veil
unimpregnated and
available to accept resin 14 from the weir 42 and act as a continuous path for
air removal from
the reinforcement pack within the injection die to the atmosphere. By
carefully designing the
thickness tapers of the injection die such that the minimum thickness is
equivalent to the
thickness the reinforcement pack would be compacted to within the curing die
and this thickness
occurs at the downstream end of the weir 42 (resin 14 input device) a pressure
gradient is set up
within the impregnated area of the reinforcing pack which forces the flow of
fluid (air and/or
resin 14) toward the entrance of die. As long as an uninterrupted path is
maintained between the
leading edge of the resin 14 in the wedge 44 and the entrance of the
impregnating die air will
flow out of the entrance of the die and no voids will enter the curing die. If
however too much
prewet 24 is applied to the donor layer and or the design of the taper in the
injection die is
incorrect and resin 14 blocks the outer layers of the reinforcing pack, air
with be trapped in the
pack and transferred to the curing die where it will form either a blister or
crack in the cured
laminate as it exits the curing die. The prewet 24 is designed by controlling
pressure and
dimensions to transfer limited amounts of resin 14 so that as the partially
impregnated
reinforcing pack is compacted in the injection die taper there is insufficient
volume of resin 14 to
impregnate all the layers between the donor layer and the die surface. The
injection die is
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CA 02679778 2009-09-22
designed so the taper is continuous and gradual so that transfer from donor
layer to acceptor
layers would be uniform. Both designs are balanced so that the result is a
system which allows
for continuous air removal as the final part 40 of the reinforcing pack is
impregnated with the
topcoat resin 14 in the impregnation die.
[0161] Figure 8A shows a cross-sectional side view of the preform injection
die design.
Partially impregnated reinforcement enters the right side of the preform. Air
that is 'carried into
the preform with the reinforcement also escapes back out the opening. Excess
resin 14 that is
squeezed out of the reinforcement is collected and returned for reuse through
openings in the
preform near the entrance. The slot 50 through which the reinforcement passes
forms a tapered
wedge 44 in the die starting essentially at about its center. The fully
impregnated reinforcement
passes through the weir 42 which receives resin 14 under pressure that is
inputted from a
pressure pot. After the impregnated reinforcement passes through the weir 42
and receives the
resin 14 in the weir 42, it passes out of the preform and moves to the curing
die. Figure 8B
shows the pressure in the die of the preform as a function of location in the
die. The pressure is
highest between the weir 42 and the exit, where it is essentially constant, or
slightly increasing.
The pressure before the weir 42 is essentially of a constant slope increasing
along the tapered
wedge 44. Before the tapered wedge 44 the pressure is essentially constant in
the die and about
that of atmospheric pressure.
[0162] The weir 42 has the following constraints.
101631 1. it must be of a size to transfer sufficient resin 14 to the part 40
to fill the
unwet layers (width fixed by 3. below, this normally set depth -- ( the Q in
the slot 50 should be higher than the required Q to wet the part 40).
[0164] 2. it must be of sufficient length such that the entire perimeter of
the part 40
is wet.
[0165] 3. A guideline that contact time of I second would be good however it
is
preferably .5 secs. contact time = weir 42 width/ line speed for example a
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CA 02679778 2009-09-22
one inch wide weir 42 run at 100 inches per min would have a contact
time of 1/100 minutes or .6 seconds
[0166] 4. It can't be too wide; otherwise, the veils catch and roll inside the
weir 42
and there can be no dead spots where material could accumulate and cure.
(This defines shape.)
[0167] A clear distinction between the composition of resin 14 in the rovings
layers and
the composition of resin 14 in the outer mat layers is maintained by the
physics of the process. It
insures the resin 14 without filler in the outer mat layers is not mixed with
resin 14 with filler
from the donor layer so the increased weatherability of the rail 16 produced
is maintained.
[0168] Because the resin 14 and filler from the donor layer in the rovings
layer is there
first and the pressure required to move it is higher than the back pressure
along the
unimpregnated outer mat--resin 14 from impregnation weir 42 follows a path--
the one of least
resistance-only into the outer mat layers.
101691 The compaction of the reinforcing pack has already pushed the resin 14
in the
central donor mat into the acceptor roving layers. This process occurs prior
to the external veil
and roving seeing the high pressure resin 14 at the weir 42. With a taper of
.003 in/in and
thickness at the weir 42 of <.001 in larger than the final dimensions in the
curing die, all but the
final 2 mils of compaction of the donor layer occurs before 5 inches behind
the weir 42. This
means that the resin 14 from the donor layer should have reached within .002
inches of the
outside edge of the roving layer.
[0170] Referring to figures 2, 4, 5, and 6 because there is control where the
prewet 24
resin 14 and the topcoat resin 14 goes within the part 40 the cross section of
a part 40 made with
this type of process is easily distinguished from a part 40 made by
conventional wetting methods.
This is especially true with systems where a pigmented veil is used as the
source of color within
the part 40. If one polishes the cross section of a ladder rail 16 using
normal polishing methods
(reference) the layers of reinforcement within the part 40 are visible by
optical microscopy, The
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CA 02679778 2009-09-22
layers may be separated by machining away layers and leaving a specific layer
exposed on the
surface of the part 40. Each layer may be isolated and visually examined and
/or examined using
other instrumented or non-instrumented methods (bum off to determine if the
outer layers have
filler ). One skilled in the art can look at the cross section and see if some
form of colored veil is
contained in the process even without help of the microscope. Thus, samples of
ladders
manufactured by competitors who would ignore this patent could be found out
with minimum
difficulty in the laboratory and even be screened by visually looking a cut
edges of the rail 16
without destroying the part 40. A diamond or carbide cut off saw is used to
create a 1 thick piece
of the section 52. This section 52 is put in clear epoxy resin 14; cure and
polish the surface of the
cast segment-- using techniques developed for polishing metal surfaces for
grain analysis. The
polished surfaces can be looked at under optical microcopy and each layer
distinguished as to
type. Because the topcoat resin 14 and prewet 24 resin 14 formulas are
different colors their
location within the thickness can be observed. In most cases, the resin's 14
interface at the
roving/outer mat interface is easily seen. Sample preparation techniques are
described in
Preparation and Examination of Aluminum Samples for Failure Analysis. By. Brad
Peirson.
School of Engineering. Grand Valley State University. Laboratory Modules 1& 2.
EGR 250
Materials Science, incorporated by reference herein.
[0171] Figure 13 shows a perspective view of the prewet 24 station, with the
slot 50
being the fixed version. Critical issues regarding the use of the prewet 24
station are the
following.
[0172] 1. The slot 50 is fixed between the uncompressed thickness of
reinforcement
and thickness required for maximum transfer to the section 52.
[0173] 2. The transfer is controlled by input mass flow and ability of keeper
D to
prevent flow out the rear of the die.
[0174] 3. As long as the input mass flow and output on the reinforcement
through
slot A is balanced, a constant amount of resin 14 will be transferred to the
donor reinforcement.
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CA 02679778 2009-09-22
[0175] 4. Slot A may be a constant thickness or changed in thickness to match
the
needs of the receptor layers for resin 14 along the width of the part 40.
Letter A, as shown in figure 16, is one half the height of the slot. In all
cases the keeper D is less than the either Q or R, whichever is smaller.
This forces the flow forward.
101761 5. The resin 14 transfer is varied with speed by adjusting mass flow
input
from pump or pressure in the tank.
[0177] Figure 15 shows a top view of the bottom half internally of the prewet
24 station.
[0178] Figure 14 is a bottom view of the top half internally of the prewet 24
station.
[0179] Figure 16 is a side view of a cross-section of the bottom half of the
prewet 24
station,
[0180] A equals one half the height of the slot
[0181] B equals one half the depth of the reservoir
[0182] C equals one half the height of the prewet 24
[0183] D equals half the height of Q or R, whichever is smaller, and to
minimize
backflow
[0184] E is the entrance to the taper
[0185] F is the resin entrance.
[0186] Explanation of the drawing of the three types of slots 50, as shown in
figures 17-
19.
[0187] If you look at the type of "U" channel Werner makes, they can be broken
down
into three categories: heavy weight extension and step rail 16, light weight
extension rail 16 and
light weight step rail 16. The characteristics of each type of rail 16 is that
they are all standard
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CA 02679778 2009-09-22
seven layer laminates with the same thickness of veil and mat. What is changed
is the amount
and distribution of roving throughout the width of the part 40.
[0188] In the heavy duty step and extension rails 16, the amount per inch of
roving in the
flange areas of the U channel are much greater than the relative amount per
inch in the web 18. [
Section 57821 would be typical of this type of rail 16. The flange thickness
is .222 inches of
which .154 in of the thickness is two .077 in roving layers. The web 18 of
this section is .165
inch thick. It contains two roving layers of .0485 in thickness.] Thus, the
center donor mat must
transfer almost twice the volume per in of resin 14 into the flange areas of
the acceptor layers as
it transfers into the web 18 area of the acceptor layers in order to fully
saturate both areas
equivalently without putting excess resin 14 in the web 18 area which could
cause air entrapment
in the injection die.
101891 The drawing of the slot 50 with much thicker outside segments
represents the
method by which this distribution of resin 14 within the donor mat is
achieved. The mat would
be fully saturated in the prewet 24 in its uncompressed thickness. The mat
would then be
differentially stripped by the slot 50 and allowed to return to its
uncompacted state as it exits the
prewet 24 die. Air would replace the resin 14 that was removed by the
stripping action of the slot
50 as the mat returns to its natural thickness. By stripping more from the web
18 than the flange
sections of the donor mat the proper distribution of resin 14 is developed
such that there is
sufficient resin 14 available in the proper location to fully impregnate the
acceptor roving layers
even though the layers are not uniform across the width of the part 40.
[0190] The slot 50 with slightly larger outside segments acts the same way as
the
previous slot 50 and used for light weight extension rails 16 such as 62418
where the flange
roving layers are about 30% greater in thickness than the web 181ayers.
[0191] The uniform slot 50 is used for lightweight step rail 16 where the web
18 and the
flange are essentially equal in thickness and roving layers are almost
uniforrn across the part 40
width. Part 63101 is an example of this.
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CA 02679778 2009-09-22
[0192] In all cases the slot 50 design is such that as the donor mat exits the
prewet 24 it
contains the proper amount of resin 14 that when the reinforcement pack is
compress by the
injection die to within mils of its final thickness in the curing die
sufficient resin 14 will be
transferred from the donor mat to the acceptor rovings so that the acceptor
rovings are fully
saturated with prewet 24 resin 14.
[0193] All the design calculations for slot 50 thicknesses and distribution
along the width
are done by looking at the designs of the sections 52 and understanding the
thicknesses to which
various materials will compress under the pressures induced in the curing die
during the
pultrusion process. A. McCarty and J. G. Vaughan, A Pressure Rise Inside a
Cylindrical
Pultrusion Die for Graphite/Epoxy Composites, @ Poly- mers and Polymer
Composites , 8 (4)
231-244, 2000. Brief, incorporated by reference herein, discusses the pressure
distribution within
the curing die. Microscopic analysis of layer thicknesses has also helped
establish these numbers.
The calculation now becomes a simple mass balance assuming that no air is
allowed into the
final product (void volumes in pultrusions are normally less than 1% for
injection die parts).
Volumes of resins 14 are converted into thickness of donor mat and slots 50
are designed
accordingly. The key to making it all work is to not oversaturate the donor or
overcompress the
donor acceptor package prior to the curing die.
[0194] Referring to figure 9, unimpregnated middle mat (I) is pulled at
constant speed
through prewet 24 station (X). Prewet 24 station (X) is supplied with a
controlled mas flow of
prewet 24 resin 14 (II) which is balanced to the resin 14 requirements of the
section 52 and set
by the operator using calibrated flow guidelines described previously. The
impregnated donor
layer (middle mat) (XI) exits the pulling station X and is combined (stacked)
with top and
bottom roving layers (III) and top and bottom mat layers (IV) using the first
of two horizontal
and vertical positioners (V). The combined section (XII) proceeds to second
horizontal vertical
position V at which the outside veils (VI) are added to the top and bottom of
the pack. The pack
continues to positive veil placement device (VII) which folds the lower veil
around the outer
edges of the pack and over the edges of the top veil. (For colored veil, this
prevents any non-
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CA 02679778 2009-09-22
colored reinforcement from being visible on the surface of the part 40 and
causes the overlap of
the top and bottom color veils to occur at a constant position and with a
constant amount of
overlapped area.)
101951 The positive placement device is congruent to the entrance of the part
former
(VIII). As the pack continues through the part former (VIII), the pack is
folded from a flat
section 52 to a "u" channel shape. During that change in geometry, the pack is
compressed
slightly but not stretched (mats would tear).
101961 From the exit of the folder, the "u" shape pack enters the "tapered"
impregnation
chamber IX. Where the top coat resin 14 is added and remaining air removed as
described by
Gauchel and Lehman. (The key to this on any other process that uses injection
is the placement
of the resins 14 such that air is forcibly removed from reinforcement pack.
Continuous path(s)
for air removable must be maintained or blisters will be evident on the final
part 40. Both
continuous strand mat and unwet roving act as paths for air from the
impregnation weir 42 in the
impregnation (IX) to the space between the entrance of the impregnator 26 and
the exit of the
folder. For a properly running impregnation system, the outer layers of the
reinforcing package
at this position should remain free of resin 14, so air can be removed. For
thin parts such as
window lineals ran at high speed, the air sounds like a train as it rushes out
of the back of the
impregnating die. Parts 40 may be as thin as .040 inches in wall thickness on
a closed hollow
section 52.
[01971 Figure 9 shows a schematic of the controller impregnation. The
unimpregnated
donor layer enters the prewet 24 station where prewet 24 resin 14 is
introduced. The now
impregnated donor layer passes out of the prewet 24 resin 14 station where it
is joined with the
un-impregnated top mat layer, a top roving layer, the bottom roving layer and
the bottom mat
layer. Horizontal and vertical layer placement guides 48 guide the different
layers together to the
impregnated donor layer, As they are pulled along, the top veil and bottom
veil layers are added
to them which are again guided by horizontal and vertical layer placement
guides 48. A top veil
and bottom veil has tensioning guides 48 to maintain the tension on the top
and bottom veil
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CA 02679778 2009-09-22
layers. All the layers then pass through a positive veil placement device and
then enter the
former 46. The cross-section of the slot 50 through which the layers enter the
former 46 is
essentially rectangular while the cross-section of the slot 50 from which the
layers exit the
former 46 has a C shape. The former 46 converts the flat with or cross-section
of the layers to a
C channel cross-section and partially compacts the layers to initiate a
transfer of resin 14 from
the donor layer to the acceptor layers. From the former 46, the layers move to
the impregnator
26. The impregnator 26 has a tapered cross-section. High-pressure resin 14 is
impregnated into
the layers at the weir 42 located just next to the point of maximum
compaction. The resin 14 is
injected into the weir 42 for wetting the outer layers, as described above.
[0198] Figure 10 shows section C of figure 9. Figure 11 shows section B of
figure 9, and
figure 12 shows section A of figure 9. Figure 12 shows the five layers that
have been brought
together at that point of the process. The saturated middle mat 38 with resin
is the donor layer
and the proving layers 34, 36 on each side of the middle mat 38 are acceptor
layers.
[0199] Prewet 24 Station Variable Slot Version
102001 Referring to figures 20 and 21, slot A is adjustable to different
thickness to apply
exactly the amount of resin 14 needed. Must be adjusted for each speed or
adjusted to maximum
speed and allowed to transfer extra resin 14 or start up as speed increases.
102011 Compaction bolts adjust slot A and keeper D as in previous drawing such
that
resin 14 moves forward out of slot A with reinforcement. Inlet pressure keeps
reservoir full on
an as needed basis. Pressure or flow rate can be sporadic as long as reservoir
has suf6cient resin
14 to saturate reinforcement (mat) a sit exits slot A.
102021 Referring to figures 22 and 23, there is shown a front view and a back
view,
respectively, of a continuous former 46. The former 46 converts the flat
shaped reinforcing pack
to the approximate shape of the formed part 40. The former 46 compacts the
reinforcing pack
slightly to prevent transfer of prewet 24 resin 14 from the donor layer to
acceptor layers.
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CA 02679778 2009-09-22
Approximately 30% of transition is accomplished in the former 46. If there is
too much
compaction, it results in an increased pull the forced by as much as 50%.
[0203] The graphic is printed on fabric using a digital printer, similar to
what is used with
a PC, only larger. The graphic is designed or loaded into a computer and then
sent to the digital
printer. For instance, the Fabric Superior Textile Printer sold by ITNH, Inc.,
can be used for this
purpose. Graphics on veil can be incorporated with the use of digital printing
equipment for
producing logos, patterns, artwork replications, photographic images, and
blends of transitional
colors. Through the selection of inks and veil pre-treatments, good graphic
resolution and UV
resistance can be obtained. Images rendered to digital format can utilize
digital printers, dryers,
and sublimators to reproduce those images on a veil that comprises the outer
wrap of a pultruded
composite, such as a ladder side rail. As the veil in its final pultruded form
is positioned below
a layer of clear resin, graphics are largely protected and can not be easily
scratched off, as can
occur with surface painting. Multiple graphics can be printed in a column
arrangement on a
single veil master roll and subsequently slit into narrow rolls to separate
the individual graphics
prior to pultrusion, making custom and low volume products economical.
[0204] Figures 26 and 27 are photographs of portions of ladder rails with
graphics.
[0205] Although the invention has been described in detail in the foregoing
embodiments
for the purpose of illustration, it is to be understood that such detail is
solely for that purpose and
that variations can be made therein by those skilled in the art without
departing from the spirit
and scope of the invention except as it may be described by the following
claims.
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