Roll cover for flat work ironer

An improved roll cover for use on a flat work ironer is provided, having an improved resin coating. The roll cover is a sheet of thermally resistant fabric which is coated or impregnated with a mixture of an acrylic resin and a stiffening agent. The improved roll cover can be dyed to a particular desired color and will retain its color over extended use.

FIELD OF THE INVENTION 
The invention relates to a roll cover for a flat work ironer of the type 
provided with a plurality of ironing rolls adapted to rotate in 
complementary seats in the upper surface of a steam chest for ironing flat 
work as the flat work is caused to move between the chest and the rolls. 
More specifically, the invention is directed to a roll cover which is 
formed by coating a thermally resistant fabric with an acrylic resin 
blended with a stiffening agent. 
BACKGROUND OF THE INVENTION 
A flat work ironer is a machine used in commercial or industrial laundries 
which serve large institutions such as hotels, hospitals, or restaurants 
to mechanically heat and press flat items such as bed linens, aprons, 
table linens, etc. The machine has a series of parallel rolls which are 
positioned in complementary-shaped semi-cylindrical polished seats formed 
in a chest that is heated by means of gas, steam, or thermal liquids such 
as hot oil. 
The ironer functions by causing the flat work to be pressed between the 
heated chest and each roll in succession. The complementary shape of the 
rolls versus the shapes of the polished seats of the heated chest causes 
the flat work to be retained in contact with the heated chest longer than 
it would be if the heated chest were flat, so as to cause the moisture in 
the flat work to quickly evaporate and to remove the folds and wrinkles 
from the flat work. The chest typically is heated to and maintained at a 
temperature of at least approximately 300.degree. F. but may reach 
temperatures of up to 450.degree. F. The flat work typically is partially 
wet after having been washed and spun to a damp condition and is fed in at 
one end of the ironer by a surface conveyor, passed between the heated 
chest and the rolls and exits at the other end of the ironer in a 
substantially dry and wrinkle-free condition. 
Typically, the rolls are fabricated of stainless steel and are hollow with 
a perforated cylindrical skin and perforated end walls to allow for steam 
generated in the ironing process to pass from about the cylindrical 
surfaces of the rolls into the interior of the rolls where it is removed 
by a vacuum system through one or both of the end walls of the roll. This 
creates air movement through and about the flat work so as to remove the 
high humidity air from about the ironer. The rolls usually are wrapped 
with a cushioning pad and then with an outer roll cover. The cushioning 
pad is typically made of a thermally resistant material such as, in the 
past, asbestos. More recently, this material is a combination of polyester 
and cotton or 100% recycled aramid or a combination of recycled aramid, 
polyester and/or cotton. 
The roll covers must be thermally stable and hydrolysis resistant to 
provide for a wear life of at least one year under use of at least 40 
hours per week. The covers should be of adequate stiffness to ensure a 
wrinkle free and smooth ironing surface. However, the cover should be 
porous to allow for the passage of steam through the cover. 
In the past, roll covers for flat work ironers have been manufactured of 
asbestos fabric. For example, U.S. Pat. No. 2,333,824 to Schoepf teaches a 
ironer roll where both the pad and the outer cover are manufactured from 
asbestos. U.S. Pat. No. 2,497,696 to Smith teaches a cover made of 
asbestos fibers adhesively applied to a underlying pad. Other covers 
taught by the prior art references have been composed of muslin or duck, 
see U.S. Pat. No. 1,539,916 to Siever, and aluminum, see U.S. Pat. No. 
2,762,111 to Morgan. 
U.S. Pat. No. 3,811,164 to Faress, et al teaches the use of a cover 
composed of a fabric which has been impregnated with a thermosetting 
resinous material, specifically a phenolic resin. Preparation of phenolic 
resins requires the use of the chemical phenol which is a hazardous 
substance. 
There are some disadvantages to use of the roll covers as taught by the 
prior art. Perhaps the most obvious are the environmental and health 
dangers associated with asbestos and phenol. Other problems with prior art 
roll covers have been in attaining desired characteristics such as 
porosity, smoothness, heat resistance, and wear resistance. Another 
disadvantage to the covers now used which are made with a phenolic resin 
is the appearance of the roll cover. These covers are brownish-yellowish 
in color when made and turn a darker brown as they are used. The 
manufacturers of the roll covers apparently have not been able to 
fabricate roll covers of different colors which retain the original colors 
over substantially the entire lifetime of the roll cover. Thus, the 
overall appearance is unaesthetic and the color instability of the covers 
makes them inconsistent and nonuniform in appearance. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a roll cover for a flat 
work ironer which overcomes the deficiencies and disadvantages of the 
prior art as described above and as generally known in the art. 
Accordingly, it is an object of the present invention to provide a roll 
cover for a flat work ironer which is coated or impregnated with an 
acrylic blend resin and which functions in a superior manner over current 
roll covers. 
It is an additional object of the present invention to provide a roll cover 
which has superior performance characteristics such as heat and wear 
resistance, porosity, stiffness and which is manufactured of non-hazardous 
materials. 
A further object of the invention is to provide a roll cover which allows 
for greater color selection and better color stability and durability. 
A still further object of the invention is to provide a roll cover for a 
flat work ironer which is more economically efficient because it is 
manufactured at a low cost and has superior performance qualities. 
To achieve the above objects, a cover is taught for a flat work ironer roll 
which provides many advantages over the prior art in this area. 
Briefly described, the present invention comprises a cover for a roll of a 
flat work ironer which comprises a thermally resistant fabric that is 
coated or impregnated with an acrylic resin which has been blended with a 
stiffening agent. The acrylic resin is safer and less expensive to apply 
to the thermally resistant fabric than phenolic resins which are currently 
used. The acrylic resin coated fabric provides necessary thermal 
resistance and structural stability at the high moisture and temperature 
conditions of the ironers. The cover made of the acrylic blend resin has 
increased porosity over phenol resin coated covers which allows for more 
moisture to be pulled through the cover. This allows for the ironer to be 
run at higher speeds thus leading to higher efficiency and production 
rates. 
The present invention has increased color selection and stability over the 
known prior art covers. The prior art phenolic resins typically have a 
yellow shade when first applied to the roll cover material. This shade 
darkens to a brownish color when the coated fabric is cured during 
preparation of the cover and further darkens over time with the operation 
of the rolls. The acrylic blend resin, however, is initially colorless and 
typically does not darken with thermal exposure. The coated fabric may be 
colored by adding dye to the resin baths, and the fabric so coated with an 
acrylic blend which contains a dye will remain substantially on shade 
during prolonged use. This increased color selection and color stability 
allows for a more aesthetic appearance and also allows for the choice of 
utilization of specific colors for specific products, customers, uses, 
etc. Also, the uncoated fabric may be dyed to the desired shade before the 
clear acrylic resin is applied to yield a final colored coated fabric. 
In accordance with the above objects the following detailed description is 
offered to allow enablement of the invention. The following description 
does not limit the invention to the description provided and it will be 
apparent to those skilled in the art that alternatives to the disclosed 
embodiment may also work.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now in more detail to the drawings in which like numerals 
indicate like pans throughout the several views, FIG. 1 shows a flat work 
ironer 10 of the type typically used for ironing flat piece goods such as 
tablecloths, napkins, bed sheets, etc. Ironer 10 includes a work table, or 
surface conveyor 12, which includes an entry roll 14, a return roll 16, 
and conveyor belts 18 that extend around the entry roll 14 and return roll 
16 and rotate in the direction indicated by arrow 19. One of the rolls of 
the surface conveyor 12, such as return roll 16, is driven by an electric 
motor 22 (FIG. 5). Feed roll bar 24 extends across surface conveyor 12 and 
rotates oppositely from conveyor belts 18, in the direction indicated by 
arrow 25. Heated chest 26 lies adjacent and parallel to and at the same 
level as surface conveyor 12 and is heated to a temperature of, 
preferably, 300.degree. F. to 330.degree. F. by means which are known in 
the field, preferably by means of circulating hot gas, steam or hot oil. A 
plurality of polished parallel recesses 28 (FIG. 2) are formed in the top 
surface of heated chest 26 and are essentially semi-cylindrical troughs 
which correspond in shape and size to rolls 30 and which function as seats 
for the rolls 30. A series of typically six rolls 30 (only four are 
illustrated in FIG. 1 ) extend across heated chest 26, oriented 
essentially parallel to each other. 
As shown more clearly in FIG. 5, a roll 30 has roll core 32 which typically 
is a stainless steel cylinder having a cylindrical wall 33. In the 
preferred embodiment, roll core 32 defines a plurality of perforations 34 
in cylindrical wall 33 which function as air passages. Each roll core 32 
is enclosed on both ends by end plates 36 which have extended therefrom 
shafts 38 which are connected to electric motor 22 and an intermediate 
drive system 40 to rotate rolls 30. At least one end plate 36 of the roll 
core 32 also has slidably attached thereto a stationary vacuum shoe 42 
which communicates with the inlet of a blower 44 so that the blower 44 
pulls a vacuum on the interior area of roll core 32. 
FIGS. 3 and 4 show the construction of a roll 30 in more detail. A heat and 
moisture resistant pad 46 wraps around roll core 32. The pad may be 
protected from contact with the roll core 32 by placement of a screen 
cloth 45 (FIG. 3) between the roll core 32 and the pad 46. Screen cloth 45 
can be made of any heat-resistant material, such as aramid fiber. Pad 46 
is of substantially the same width as the length of roll core 32 and of 
sufficient length to wrap around roll core 32 one time. Preferably, pad 46 
wraps around roll core 32 slightly less than one time so that as the roll 
10 is used and pad 46 becomes compressed it does not start to overlap on 
itself. The trailing end of pad 46 trails freely behind as the roll 30 
rotates in the direction away from the trailing end, as indicated by arrow 
31. 
Pad 46 can be composed of any of several suitable materials which are used 
in the field. For example, pad 46 can be a mixture of polyester and 
cotton, 100% recycled aramid, or a mixture of recycled aramid, polyester, 
and/or cotton. Aramid is the generic name for fiber made from the 
condensation product of isophthalic or terephthalic acid and m-or 
p-phenylenediamine. Pad 46 also can be a stainless steel knitted material. 
Roll cover 50 is positioned about pad 46. Preferably, the leading end 51 of 
cover 50 is attached to roll core 32 by fasteners such as series of rivets 
or grommets 49. As shown in FIG. 3, which shows the assembly of a roll 
when a screen cloth 45 is placed between the roll core and the pad, cover 
50 is fastened to roll core 32 at a line of connection 53 on roll core 32 
ahead of attachment of pad 46. Cover 50 is spirally wound around roll core 
32 on top of pad 46 and wraps round pad 46 and roll core 32 approximately 
two times. 
A second embodiment of the roll cover, pad and roll is shown in FIG. 4. 
This is the preferred assembly of the roll and its cover when a screen 
cloth is not used. In this second embodiment, cover 50 is attached to the 
roll core at a line on roll core 32 past the line of attachment of pad 46. 
Cover 50 thus wraps around roll core 32 once under pad 46, then a second 
time on top of pad 46. In both embodiments of the invention the free end 
52 of cover 50 is not fastened but instead trails freely. As the roll 10 
is used this trailing end 52 can move to avoid bunching up of the cover 50 
with expansion, compression or stretching of the pad or cover. 
Cover 50 is formed of a resin coated thermally resistant fabric. The base 
fabric is one which can withstand exposure to temperatures up to 
450.degree. F. for prolonged periods of time. An example of an appropriate 
fabric is one made from woven aramid fiber. Other suitable fabric 
materials, by example, are flame resistant polyester, polybenzimidazole, 
polytetrafluoroethylene, polyetheretherketone, polyetherimide, 
polyethersulfone, polyimide, polyamide, polyimide-amide, modacrylic, 
acrylic, melamine, and glass. 
The base fabric of cover 50 is woven and coated with a resin blend by means 
which are known in the art. Typically, a resin bath is used to coat the 
fabric evenly on both sides. The fabric is completely submerged in the 
bath and then the fabric is removed from the bath and rollers are used to 
squeeze the excess resin off the fabric. Alternatively, a system designed 
to apply latex to the back of carpet may be used. In this system, the 
fabric passes over the top of a roller which is half submerged in the 
resin bath. As the roller rotates it applies resin to the fabric and 
excess resin is removed from the fabric using a scraper blade. The fabric 
is then placed in an oven to dry the fabric and cure the resin. Typically, 
the drying/curing is accomplished using a tenter frame at an oven 
temperature of 390.degree.-400.degree. F. and the fabric is passed through 
the oven at a rate of approximately 5-20 yards per minute. The acrylic 
resin on the coated fabric of the present invention cures more quickly 
than phenolic resins used to coat fabrics currently. Therefore, the 
acrylic resin coated fabric of the present invention can be passed through 
the oven at a faster rate and the cost of curing the product is lower than 
the cost of curing the prior art phenolic coated product. 
The resin blend of the present invention can be from about 4 to 40% by 
weight acrylic resin, preferably about 16 to 26%, and from about 2.5 to 
30% by weight of a stiffening agent, preferably from about 5 to 15%. An 
anti-migrant agent may also be included as may a cross-linking catalyst 
such as ammonium chloride. If these are included they are each &lt;1% by 
weight. The remainder of the bath is water. It is also anticipated that 
other resins may be used, such as, for example, a self cross-linking 
acrylic resin. In this case, a stiffening agent would not be required. 
Preferred acrylic resins are acrylic copolymers such as, for example, but 
not limited to, GLOCRYL. GLOCRYL is the tradename for an anionic 
self-crosslinking acrylic copolymer manufactured by Glo-Tex Chemicals, 
Inc., P.O. Box 1019, Railroad Street, Roebuck, S.C. 29376. This acrylic 
copolymer has a boiling point of 212.degree. F., a vapor pressure of 17 
mmHg at 20.degree. C., a specific gravity of 1.1 and is 55% volatile. The 
acrylic copolymer is an opaque water based emulsion, 55% water, with a low 
acrylic odor. 
A stiffening agent is added to the acrylic resin in the resin bath to 
increase the "hand", or feel, and stiffness of the final coated fabric. 
The stiffening agent cross-links with the acrylic copolymer and forms a 
stiffer polymer than the acrylic copolymer would form polymerizing with 
itself. Stiffening agents include, but are not limited to, aqueous 
polymeric solution, hexamethoxymethyl-melamine, modified fatty amides, 
modified alkyd resin, modified formaldehyde carbamate, modified urea 
formaldehyde carbamate, melamine-formaldehyde, polyvinyl acetate, 
polyvinyl alcohol, polyurethane, polyethylene emulsion, polyether 
thermoplastic polyurethane, triazine-formaldehyde condensate, vinyl 
co-polymers with modified starch, other thermoplastic resins, and other 
thermoset resins. 
An antimigrant agent may be added to the resin blend to stop migration of 
dye particles through the coated fabric and to maintain uniformity of 
color shade across the coated fabric. Examples of anti-migrant agents 
which are suitable are nonionic, linear polymeric anhydride, anionic 
polyacrylamide and formulated polyamide anti-migrant agents. ASTROTHERM 
AM, a formulated polyamide manufactured by GLO-TEX Chemicals, Inc. of 
Roebuck, S.C., was used with successful results. 
A cross-linking catalyst such as ammonium chloride may be included in the 
resin to speed up the polymerization reaction between the stiffening agent 
and the acrylic copolymer. 
The resin blend may also include one or more coloring agents, such as 
pigments and dyes, to impart to the coated fabric the desired color. Acid 
dyes have been used in the present invention with success due to the small 
size of these dye particles. However, any coloring agents which do not 
migrate across the fabric and which do not leach off of the fabric during 
use of the roll covers would be suitable as well. 
OPERATION 
The flat work 54, preferably dampened, shown in FIGS. 1 and 2 as a table 
napkin, enters ironer 10 across surface conveyor 12 via transportation by 
conveyor belts 18 and feed roll bar 24. Flat work 54 follows the movement 
of directional arrows 56 shown in the several views of the invention. Flat 
work 54 then moves across heated chest 26 and sequentially through each 
recess 28 and underneath each roll 30. Rolls 30 rotate in the direction 
indicated by arrow 31 and push/pull flat work 54 across the ironer 10. 
Each roll 30 contacts the flat work and flat work 54 is pressed or ironed 
between each roll in its corresponding recess. This contact with heated 
chest 26 and each roll 30 presses and dries flat work 54. The moisture 
from flat work 54 is evaporated into the air and also is pulled from flat 
work 54 by the vacuum created in the interior of roll core 32. Thus, 
moisture is pulled from flat work 54 through cover 50 and pad 46 and 
through the perforations 34 of roll core 32. The moisture is then pulled 
out of the ironer by vacuum means. Flat work 54 exits ironer 10 pressed 
and dried. The speed of rolls 30 can be adjusted to ensure flat work 54 
stays in the ironer long enough to become dry. 
EXAMPLE 1 
A roll cover was fabricated as follows: 
A woven material was formed with aramid warp and filler yams, with 37.5 
warp yams per inch and 37 filler yams per inch. The denier of both yams 
was 665 (16/2 cotton count). 
Once the fabric was woven, it was submerged in a bath of acrylic resin, a 
stiffening agent and dyes. The acrylic resin was GLOCRYL NCR, and the 
stiffening agent was AEROTEX M-3 Resin. The acrylic resin of the liquid 
mixture was 21% by weight, the stiffening agent was 9% by weight. Acidol 
Dyes from BASF, Red, Blue, and Yellow were used to color the fabric in the 
following amounts: 
______________________________________ 
Color % by Weight of Bath 
______________________________________ 
Red 0.045 
Blue 0.023 
Yellow 0.630 
______________________________________ 
Also included in the bath were an anti-migrant (Astrotherm AM--0.90%), and 
a catalyst (Ammonium Chloride--0.50%). The liquid bath was maintained at 
ambient room temperatures. The dyes were separately dissolved in hot water 
before mixing with the other diluted ingredients. 
The fabric was submerged in the resin and then run through a pair of pad 
rollers which squeezed the excess resin out of the fabric. Because this 
was a continuous operation, the time of submersion varied with the speed 
of the tenter frame. The pad rollers maintain a constant pressure, 
however, and so resin pick-up tends to be uniform regardless of production 
speeds. 
The resin impregnated fabric was then passed through a drying oven 
maintained at 400.degree. F. for a period of 2 to 3 minutes. The rate of 
passage of the fabric was 15 yards per minute. The fabric passed through 
cooling zones at the end of the oven, which brought the temperature down 
to 150.degree. F. or less, before being rolled up on an automatic wind-up 
unit. 
EXAMPLE 2 
The process of Example 1 was repeated with the following changes: 
The resin blend was 4% by weight acrylic resin, 2.5 % by weight stiffening 
agent, by weight ammonia chloride and the balance water. The resulting 
fabric had less stiffness than the fabric of Example 1. 
EXAMPLE 3 
The process of Example 1 was repeated with the following changes: 
The resin blend was 15% by weight acrylic resin, 6% by weight stiffening 
agent, 1% by weight antimigrant agent, 0.5% by weight catalyst, 0.060% by 
weight red dye, 0.028% by weight blue dye and 0.750% by weight yellow dye. 
The resulting fabric performed acceptably, although the hand was softer 
than the fabric of Example 1. 
The products of Examples 1, 2 and 3 were cut to size and were attached over 
a pad to a roll of a flat work ironer with a heated chest and operated to 
heat and press flat work products such as pillow cases, sheets, towels and 
other hotel supplies. Over a period of one year, the color of the roll 
covers was maintained without any noticeable fading, darkening or other 
color change. Further, there was no perceptible wear on the roll covers. 
The covers functioned as well as the phenolic resin coated covers 
typically used for such work. 
While preferred embodiments of the invention have been disclosed in detail 
herein, it will be obvious to those skilled in the art that variations and 
modifications of the disclosed embodiments can be made without departing 
from the spirit and scope of the invention as set forth in the following 
claims.