Thermoformed plastic refrigerator door

A unitary plastic refrigerator door is produced by simultaneously thermoforming an outer refrigerator door panel with an inner refrigerator door liner. During production, an annular flange portion of the inner refrigerator door liner is joined with an annular sidewall portion of the outer refrigerator door panel at an attachment location positioned inwardly of the annular side wall portion. The inner refrigerator door liner is also formed with either an annular recess or a plurality of spaced recesses in its annular flange portion adjacent the attachment location of the inner refrigerator door liner and the outer refrigerator door panel that is adapted to press-fittingly receive a door gasket. Preferably, the outer refrigerator door panel includes a thickened portion that is formed with a handle defining recess. A method of thermoforming the refrigerator door is also provided and advantageously enables the inner refrigerator door liner to be produced on a male mold member.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention pertains to the art of refrigerators and, more 
specifically, to a unitary plastic refrigerator door, as well as a method 
of thermoforming the plastic refrigerator door from two plastic sheets. 
2. Discussion of the Prior Art 
It is commonly known to produce a refrigerator door by independently 
manufacturing the various components that combine to make the door and 
then, in a separate manufacturing step, assembling the various components. 
For example, as represented in FIG. 1 of this application, it is common to 
form an outer refrigerator door panel 5 from a single stamped sheet of 
metal which is folded in order to form sides 8 and inwardly turned flanges 
10. The inner liner 13 associated with such a refrigerator door is often 
thermoformed on a male mold member. In general, such an inner liner 13 is 
made on the male mold member because of the high draw ratios that would be 
involved with the use of a female mold member. Once the outer refrigerator 
door panel 5 and the inner refrigerator door liner 13 are formed, inner 
liner 13 is secured to door panel 5 along flanges 10, along with an 
annular gasket 16, by means of a plurality of connecting strips 18 and 
screws 20. A separate handle 22 is then secured to outer refrigerator door 
panel 5 by means of screws 24. Outer refrigerator door panel 5 is also 
generally formed with upper and lower aligned holes 27 which are adapted 
to receive pivot bushings 29 for mounting the assembled refrigerator door 
to a refrigerator cabinet. For insulation purposes, it is also known to 
inject foam between refrigerator door panel 5 and inner liner 13 after 
complete assembly of the refrigerator door. 
The manufacturing procedure associated with constructing such a 
refrigerator door formed from various, individually produced components 
which are later assembled together, is inefficient. Such a process is 
extremely time consuming and requires various manufacturing stages wherein 
the individual components are made and assembled. In addition, since the 
outer refrigerator door panel 5 is made of metal, its outer surface must 
be painted for aesthetic purposes. The need for these multiple 
manufacturing stages obviously increases the overall costs associated with 
manufacturing such a refrigerator door. 
It is also been proposed to manufacture a hollow refrigerator door formed 
entirely from plastic. Such an arrangement is generally shown in FIGS. 2, 
3a and 3b and disclosed in U.S. Pat. No. 5,306,082. According to this 
method of making a refrigerator door, the first step in the manufacturing 
process involves independently making the individual components which 
combine to form the inner door members. As shown in FIG. 2, these inner 
components generally constitute opposing side members 35, 37 and a 
plurality of shelf defining members 40-42. In general, these interior 
components are separately blow molded by arranging two parallel sheets of 
plastic between first and second mold members (see FIGS. 3a and 3b), 
closing the mold members so as to pinch the sheets about outer perimeters 
thereof and injecting air between the sheets so as to cause the sheets to 
expand against the mold members. Side members 35, 37 and shelf members 
40-42 are formed with tabs 45 which are adapted to extend within slots 48 
formed in an outer door panel 50 that is constituted by a hollow plastic 
slab which is also blow molded. In a final stage of the blow molding of 
the outer door panel 50, the tabs 45 provided on side members 35, 37 and 
shelf members 40-42 are positioned within slots 48 such that slots 48 form 
about tabs 45 in order to secure side members 35, 37 and shelf members 
40-42 to outer door panel 50. An annular gasket 52 is then secured by 
means of connecting strips 55 and screws 57 to an outer annular flange 
portion 59 of door panel 50. In addition, a separate handle 62 is secured 
to door panel 50 by means of screws 64. 
The refrigerator door construction arrangement as represented by FIGS. 2, 
3a and 3b has several advantages over the construction arrangement 
represented in FIG. 1 and discussed above. First, the entire refrigerator 
door of the FIG. 2 arrangement is formed from plastic and therefore its 
desired shape can be readily varied. In addition, such a manufacturing 
operation does not require a subsequent painting stage for outer door 
panel 50. Furthermore, making the outer door panel 50 from plastic can 
provide some additional heat efficiency benefits since the metal door 
panel of the FIG. 1 arrangement will be a better conductor of heat into 
the refrigerator than the plastic door. Finally, the use of plastic 
presents the ability to integrally form the outer door panel with a handle 
as also proposed in the prior art and represented in FIG. 4. 
However, these previously proposed all-plastic refrigerator door 
arrangements suffer from various drawbacks. For example, the various 
components which make up each of the refrigerator doors are still 
separately manufactured and subsequently assembled. As indicated above, 
this is considered inefficient as it adds to the manufacturing time and 
cost associated with making such doors. Furthermore, the known all-plastic 
refrigerator door arrangements are generally not aesthetically appealing 
since the interconnection between the various components are often 
noticeably visible and there will be a pinch line where the mold halves 
close. Finally, although forming an outer door panel of plastic with an 
integrally formed handle reduces manufacturing costs associated with the 
outer door panel and is rather aesthetically appealing, the prior proposed 
system as represented in FIG. 4 forms the handle, generally indicated in 
68, by creating a recess in the front surface 71 of the outer door panel 
74 which inherently reduces the energy efficiency of the refrigerator door 
as a whole due to its reduced thickness. In addition, there is no 
practical way in the prior art to use different materials or colors for 
the inner and outer refrigerator door panels. 
Therefore, there exists a need in the art for a plastic refrigerator door 
which can be produced in a minimum number of manufacturing stages so as to 
reduce the manufacturing costs associated with the refrigerator door. In 
addition, there exists a need in the art for a all-plastic refrigerator 
door and method of making the same wherein the energy efficiency 
associated with the refrigerator door is maintained or increased. Finally, 
there exists a need in the art for an aesthetically appealing plastic 
refrigerator door. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an improved all-plastic 
refrigerator door which minimizes the manufacturing stages and associated 
costs of producing such a door. 
It is another object of the invention to produce a plastic refrigerator 
door including an integrally formed handle that does not reduce the 
overall energy efficiency characteristics of the refrigerator door. 
It is a further object of the present invention to produce an aesthetically 
pleasing all-plastic refrigerator door. 
These and other objects of the present invention are achieved by 
simultaneously thermoforming an outer refrigerator door panel with an 
inner refrigerator door liner. By this arrangement, an annular flange 
portion of the inner refrigerator door liner is joined with an annular 
sidewall portion of the outer refrigerator door panel at an attachment 
location positioned inwardly of the annular sidewall portion wherein the 
attachment location is not visible from the front and sides of the 
refrigerator door. The inner refrigerator door liner is also formed with 
either an annular recess or a plurality of spaced recesses in its annular 
flange portion adjacent the attachment location of the inner refrigerator 
door liner and the outer refrigerator door panel in order to 
press-fittingly receive a door gasket. Preferably, the outer refrigerator 
door panel includes a thickened portion that is formed with a handle 
defining recess located outside of the door shelf and side dike perimeter 
of the inner refrigerator door liner. A method of thermoforming the 
refrigerator door is also provided and advantageously enables the inner 
refrigerator door liner to be produced on a male mold member. 
Other objects, features and advantages of the invention should become 
apparent from the following detailed description of a preferred embodiment 
thereof, when taken in conjunction with the drawings wherein like 
reference numerals refer to corresponding parts in the several views.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 5 schematically depicts a refrigerator 80 constructed in accordance 
with the present invention. Refrigerator 80 generally includes a cabinet 
83 having various compartments (not shown) formed therein that are 
selectively closed off by a freezer compartment door 86 and a refrigerator 
compartment door 88. Refrigerator 80 further includes a kick plate 90. It 
should be noted that the structure of cabinet 83 and kickplate 90 are not 
considered part of the present invention and therefore will not be further 
discussed herein. In addition, it should be noted that, although 
particular reference will be made to refrigerator compartment door 88 in 
describing the plastic refrigerator door and its method of manufacture in 
accordance with the present invention, it should be readily understood 
that the term "refrigerator door" refers to either a freezer compartment 
door or a refrigerator compartment door. Therefore, the present invention 
is equally applicable to combination refrigerator/freezers or dedicated 
refrigerator or freezer units. 
Refrigerator compartment door 88 includes an outer refrigerator door panel 
91 and an inner refrigerator door liner (not shown in FIG. 5) as will be 
more fully discussed below. Outer refrigerator door panel 91 includes an 
outer wall portion 92 having an associated surface 93 and an inwardly 
turned annular sidewall 94. Outer wall portion 92 includes a thickened 
portion 95 that projects slightly outwardly from surface 93. A plateau 
section 99 includes left and fight recess defining handles 103, 104 that 
are defined between a central plateau section 107 and left and fight 
upstanding, thickened end portions 110, 111 of thickened portion 95. As is 
commonly known in the art, refrigerator door panel 91 can be pivotally 
mounted about a vertical axis to either the left or fight hand sides of 
cabinet 83. For this reason, the left and fight halves of refrigerator 
door panel 91 are preferably symmetrically formed with the left and fight 
recess defining handles 103, 104. However, it should be readily understood 
that refrigerator door panel 91 could be designed for use in connection 
with a refrigerator 80 having a predetermined door opening side wherein 
only one handle may be required. In addition, although thickened portion 
95 is depicted in the preferred embodiment of FIG. 5 to be located at the 
upmost portion of refrigerator door panel 91, it should be readily 
understood that thickened portion 95 could be repositioned in order to 
locate handles 103 and 104 at a desired location and orientation. Since 
thickened portion 95 projects outwardly from surface 93, the formation of 
handles 103 and 104 do not detract from the overall energy efficiency of 
refrigerator door panel 91. In other words, the heat transfer 
characteristics associated with refrigerator door panel 91 are only 
increased by the presence of thickened portion 95 as opposed to the 
inherent decrease in the desired heat transfer characteristics that could 
be present if a handle was defined by a recess formed inward of surface 
93. 
In accordance with the preferred embodiment, refrigerator compartment door 
88 is made by a thermoforming process which advantageously enables the 
particular shape of refrigerator door panel 91 to be readily altered if 
desired. In addition, in accordance with the method of thermoforming a 
refrigerator door in accordance with the present invention, refrigerator 
compartment door 88 can be advantageously made from two plastic sheets 
utilizing a single molding apparatus and with a liner associated with 
refrigerator compartment door 88 being formed on a male mold member as now 
will be discussed with reference to FIGS. 6-13. 
Initial reference will be made to FIG. 6 in describing a few of the basic 
components utilized in the process of thermoforming refrigerator 
compartment door 88. The thermoforming apparatus includes upper and lower 
platens 120, 121 each of which defines support surfaces 124 and 125 
respectively. Upper and lower platens 120, 121 are integrally formed and 
are fixedly secured to control arms 127 and 128 respectively. Control arms 
127 and 128 form part of or are attached to linear actuators (not shown), 
such as hydraulic, electric or pneumatic actuators, in order to reposition 
upper and lower platens 120, 121 vertically as depicted in FIG. 6 and 
represented by arrows A and B. The basic shifting arrangement for upper 
and lower platens 120, 121 has not been detailed in the drawings since 
such an arrangement is commonly known in the art of thermoforming articles 
and is therefore not considered an inventive aspect of the present 
invention. 
FIG. 6 also illustrates a sheet supporting and shuttling member 132 
utilized in the thermoforming method of the present invention. Sheet 
supporting and shuttling member 132 includes a clamping frame 135 having 
an upper annular frame member 137 provided with a central cut-out portion 
139. Central cut-out portion 139 is sized in relation to the size of the 
molds that are attached to the upper and lower platens 120 and 121 so as 
to be slightly larger than the molds whereby the molds can be positioned 
entirely within central cut-out portion 139. Upper annular frame member 
137 is provided with first and second undercut portions 142 and 144. As 
shown in FIG. 6, a pair of sheet retaining members 147, 148 are pivotally 
attached by means of rods 149, 150 to second undercut portion 144 of upper 
annular frame member 137. Through rods 149, 150, sheet retaining members 
147, 148 can pivot between a sheet releasing position as indicated by the 
solid lines for sheet retaining member 147 on the left side of the upper 
annular frame member 137 in FIG. 6 and a sheet clamping position as 
illustrated by the position of sheet retaining member 148 in solid lines 
on the right side of FIG. 6. When sheet retaining members 147, 148 are in 
their respective clamping positions, an annular space 153 is defined 
between upper annular frame member 137 and sheet retaining members 147, 
148 which is used to retain a plastic sheet 156. In this manner, plastic 
sheet 156 can be selectively supported by sheet supporting and shuttling 
member 132 within annular space 153 or can be released by pivoting members 
147, 148. It should be noted that although only two sheet retaining 
members 147, 148 are depicted in FIG. 6 due to the view taken, additional 
sheet retaining members could be provided on the other opposing sides of 
sheet supporting and shuttling member 132. In particular, these additional 
sheet retaining members may be highly desired depending upon the required 
thickness of plastic sheet 156. In the preferred embodiment, for support 
purposes, all four sides of clamping frame 135 are provided with pivotable 
sheet retaining members. 
Each sheet retaining member 147, 148 includes an outermost terminal end 160 
that is spaced inward a predetermined distance from a downwardly extending 
portion 162 of upper annular frame member 137. This predetermined distance 
permits each sheet retaining member 147, 148 to freely pivot about its 
respective rod 147, 149. In order to prevent undesired pivoting of each 
sheet retaining member 147, 148, a locking arrangement is provided between 
upper annular frame member 137 and the sheet retaining members 147, 148. 
In one embodiment, the locking arrangement includes a plurality of locking 
pins 165 that extend through holes (not labeled) formed in downwardly 
extending portion 162 of upper annular frame member 137. Locking pins 165 
can abut outermost terminal end 160 of a respective sheet retaining member 
147, 148 or could actually extend into bores (not shown) formed in the 
outermost terminal end 160 of each sheet retaining member 147, 148. 
Locking pins 165 are slidably mounted within the through holes provided in 
downwardly extending portion 162 of upper annular frame member 137 and can 
be spring biased to a locking position. 
Reference will now be made to FIG. 7 in describing an initial thermoforming 
stage in accordance with the present invention. For forming of 
refrigerator compartment door 88, upper platen 120 has secured thereto, by 
any means known in the art such as threaded fasteners (not shown) that 
extend into support surface 124, a first female mold unit indicated at 
172. First female mold unit 172 includes an internal cavity 174 defined by 
a base 175 and an annular pillar 176. Annular pillar 176 is formed with an 
outwardly extending, tapered tongue element 177. A second female mold unit 
generally designated by numeral 182 is likewise fixedly secured upon 
support surface 125 of lower platen 121. An integral part of second female 
mold unit 182 is a cradle member 190. Cradle member 190 is formed with 
first and second dike receiving depressions 194 and 195. Cradle member 190 
also includes an annular recess accommodating member 198. 
During an initial stage of thermoforming refrigerator compartment door 88, 
a male mold member 202 is shuttled between the first and second female 
mold units 172 and 182. Male mold member 202 can be shuttled in the 
direction of arrow C' by a type of shuttling mechanism that can include, 
for example, a track and an actuator (not shown) attached to the upper 
plateau 120. Of course, the manner in which male mold member 202 is 
repositioned during the thermoforming method of the present invention can 
be performed by various types of conveying assemblies known in the art. 
Male mold member 202 is formed, on an upper surface 203 thereof, with a 
tapering annular groove 204. When male mold member 202 is shuttled between 
the first and second female mold units 172, 182 and first female mold unit 
172 is shifted toward second female mold unit 182 and the cradle member 
190 in the direction of arrow A', male mold member 202 mates with first 
female mold unit 172 with tongue element 177 extending within tapering 
annular groove 204 in order to locate male mold member 202 relative to 
first female mold unit 172. It should be understood that other alternate 
locating methods than tongue element 177 and annular groove 204 could be 
used to locate male mold member 202 relative to the first female mold unit 
172. Male mold unit 202 is also provided with a plurality of dike forming 
members 207, as well as an annular recess 209 spaced outwardly from dike 
forming members 207. At this point, it should be noted that annular recess 
209 is only depicted in FIG. 7 for clarity of the drawings. 
Shuttled into position, as best shown in FIG. 7, generally simultaneously 
with the male mold member 202 and in the direction of arrow B' is a plug 
assist 210. The plug assist 210 can be shuttled on a track and moved by an 
actuator attached to the lower platen 121. Also simultaneous with the 
shuttling of male mold member 202 between first and second female mold 
units 172, 182 and cradle member 190, a first sheet supporting and 
shuttling member 212 is shuttled between male mold member 202 and the 
cradle member 190 of second female mold unit 182. First sheet supporting 
and shuttling member 212 carries a first plastic sheet 2 15. At this 
point, first female mold unit 172 is shifted in the direction of arrow A' 
and, with the application of heat and a vacuum through male mold member 
202 in a manner known in the art of thermoforming, first plastic sheet 215 
is vacuumed onto male mold member 202. In coordination, plug assist 210 is 
moved in the direction of arrow D' to assure that plastic sheet 215 
conforms to the desired shape as defined by male mold member 202. As shown 
in FIG. 7A, the plug assist 210 is then retracted in the direction of 
arrow E' and is shuttled out in the direction of arrow F' (see FIG. 7A). 
By this process, an inner refrigerator door liner 218 is formed on male 
mold member 202. At this point, it should be noted that inner refrigerator 
door liner 218 is not shown on male mold member 202 in FIG. 7A for clarity 
only. Due to the configuration of male mold member 202, refrigerator door 
liner 218 is formed with dike portions 220, 221 and an annular flange 
portion 223. As we discuss more fully below, annular flange portion 223 
will be later bent to form an inturned edge 225 and refrigerator door 
liner 218 is later trimmed at inturned edge 225 (see FIG. 14). An annular 
recess 227 (shown only on one side of FIG. 8 for clarity) is also formed 
in annular flange portion 223 during the vacuum forming process. 
When first plastic sheet 215 is appropriately formed and a cooling process 
has taken place, female mold 182 and platen 121 is shifted in the 
direction of arrow G' and upper platen 120 is shifted in the direction of 
arrow H' as shown in FIGS. 8 and 9 and sheet retaining members 147, 148 
are shifted to their release positions. At this point, lower platen 121 is 
shifted downwardly in the direction of arrow B" in FIG. 9 wherein 
refrigerator door liner 218 is retained within cradle member 190. Although 
not shown in detail, male mold member 202 preferably includes tab portions 
229 that can pivot relative to the remainder of male mold member 202 in 
order to enable refrigerator door liner 218 to be removed from annular 
recess 209 and male mold member 202. Next, male mold member 202 and first 
sheet supporting and shuttling member 212 are shuttled out from between 
first and second female mold units 172, 182. Thereafter, a second sheet 
supporting and shuttling member 231 shuttles a second plastic sheet 234 
between first and second female mold units 172, 182. When second sheet 
supporting and shuttling member 231 is in place between first and second 
female mold units 172, 182, upper platen 120 is shifted toward lower 
platen 121 as illustrated in FIG. 10 so as to come into contact with 
second plastic sheet 234 and a vacuum is applied through first female mold 
unit 172 in a manner known in the art such that second plastic sheet 234 
is drawn into first female mold unit 172 in order to form outer 
refrigerator door panel 91 (see FIG. 11). As soon as the vacuum is 
applied, lower platen 121 is extended such that inner refrigerator door 
liner 218 and outer refrigerator door panel 91 contact each other as shown 
in FIG. 12. With the application of heat, the inturned edge 225 of inner 
refrigerator door liner 218 is melted to the inwardly turned annular 
sidewall portion 94 of outer refrigerator door panel 91 (also see FIG. 
14). Once these two portions of refrigerator compartment door 88 are 
joined, pressure is immediately applied through a blow pin (not shown) 
into the interior of the newly formed refrigerator compartment door 88 to 
enhance the details of outer refrigerator door panel 91. Next, both upper 
and lower platens 120, 121 are retracted and the final product, which is 
still attached to second sheet supporting and shuttling member 23 1, is 
shuttled out from between first and second female mold units 172, 182 as 
shown in FIG. 13. 
The interconnection between inturned edge 225 of inner refrigerator door 
liner 218 and inwardly turned annular sidewall 94 of outer refrigerator 
door panel 91 is perhaps best shown in the enlarged view of FIG. 14. Once 
the thermoformed refrigerator compartment door 88 is removed from between 
first and second female mold units 172, 182, this joined area between 
inner refrigerator door liner 218 and outer refrigerator door panel 91 is 
trimmed along line 240 which can then be rounded or beveled. When 
assembled to the cabinet 83, the trim line 240 is hidden from frontal and 
side view and a seam defined by the joined area is located between annular 
side wall portion 94 and dike portions 220 and 221 and extends 
substantially perpendicular to an outer wall portion of door panel 91 as 
clearly shown in this figure. 
In accordance with the present invention, a gasket, generally indicated at 
243 in FIG. 14, is adapted to be press fit within annular recess 227. To 
further hide trim line 240, gasket 243 may be designed to include a 
portion 245, as shown in FIG. 14, that overlies trim line 240 and which is 
flush with sidewall 94. Once gasket 243 is secured, a unitary, 
aesthetically appealing all-plastic refrigerator door is formed. FIG. 14 
also illustrates that, in accordance with the preferred embodiment of the 
invention, the internal chamber 247 defined between outer refrigerator 
door panel 91 and inner refrigerator door liner 218 can be filled with a 
heat insulating material. In the preferred embodiment, foam 249 is 
injected into internal chamber 247 and extends even into dike portions 
220, 221 in order to provide, in addition to enhanced thermal 
specifications for refrigerator compartment door 88, additional structural 
rigidity without significantly increasing the weight of refrigerator 
compartment door 88. 
FIG. 15 depicts a preferred embodiment for the gasket utilized with 
refrigerator compartment door 88. According to this preferred embodiment, 
the gasket includes a base 252 terminating in an upwardly angling portion 
255 at one end thereof. Base 252 is formed with an elongated connection 
member 260 composed of sidewall portions 262, 263 joined by a plurality of 
spaced, interconnecting portions 265-267. The gasket is adapted to be 
mounted within annular recess 227 by press fitting connection member 260 
therein. The undercut formed by sidewall portion 262 functions to hold the 
gasket in place. The spaces provided between sidewall portions 262, 263 
and interconnecting portions 265-267 enable connection member 260 to be 
readily deflected inwardly upon insertion of connection member within 
annular recess 227 in order to facilitate in the interconnection between 
the gasket and refrigerator compartment door 88. 
For sealing purposes, the gasket includes a primary seal member generally 
indicated at 280 and a secondary seal member generally indicated at 282. 
Primary seal member 280 is attached to one end of base 252 by a first flap 
member 285 and is attached to an intermediate portion of base 252 by means 
of a second flap member 286 and an enlarged attachment member 287. 
Secondary seal member 282 is also secured to base 252 at one end through 
attachment member 287 and at another end thereof to upwardly angling 
portion 255. Primary seal member 280 is adapted to engage the face (not 
labeled) of cabinet 83 and secondary seal member 282 is adapted to engage 
a liner of cabinet 83 when refrigerator compartment door 88 is closed. If 
cabinet 83 is made from metal, primary seal member 280 is preferable 
provided with an internal chamber 290 which houses a magnet (not shown) 
for enhancing the sealing characteristics in a manner known in the art. 
From the above discussion, it should be readily apparent that forming an 
all-plastic refrigerator door in accordance with the present invention 
minimizes the number of manufacturing steps necessary and results in 
reduced manufacturing costs. In addition, since the refrigerator door is 
completely made from plastic, it will be a more durable than conventional 
metal/plastic doors and can be more versatile in design. One of the key 
benefits to the manufacturing process is that the door can be manufactured 
such that the joining seam whereat the outer door panel meets the inner 
liner faces toward the inside of the refrigerator. Due to this positioning 
of the seam, the gasket could be advantageously designed to cover the seam 
so as to provide an extremely aesthetically appealing overall assembly. 
Although various materials could be utilized in connection with the present 
invention to form the refrigerator door, in the preferred embodiment, 
outer refrigerator door panel 91 is composed of a high impact polystyrene 
layer of approximately 95-98 mils in thickness having an acrylic cap layer 
of polymethylmethacrylate in the order of 2-5 mils. The refrigerator door 
liner 218 is preferably formed of high impact polystyrene. In addition, a 
foam barrier layer of a styrenic alloy may be used on the inside surface 
of both the outer refrigerator door panel 91 and the inner refrigerator 
door liner 218 when certain corrosive foams are injected within internal 
chamber 247. It is also possible to use polyvinylchloride as the material 
for either of these components. If polyvinylchloride is utilized, no cap 
layer or foam barrier will be necessary. However, the use of the 
polystyrene over the polyvinylchloride is preferred based on cost factors. 
Instead of the polymethylmethacrylate used for the cap layer, it is also 
possible to utilize styrenemethylmethacrylate. 
As indicated above, the refrigerator door constructed in accordance with 
the invention will be more energy efficient than conventional doors 
utilizing metal panels which inherently conduct more heat into the unit. 
This efficiency characteristic is further enhanced by locating the 
thickened portion of the door that contains the handles closer to the 
periphery of the door than the dike. Obviously, the plastic also provides 
a corrosion resistant door that does not require painting. When foam is 
injected within the door, the door shells are inherently stronger, even 
more so than the conventional design. 
Although described with respect to a preferred embodiment of the invention, 
it should be readily understood that various changes and/or modification 
can be made to the present invention without departing from the spirit 
thereof. For instance, the specific manner in which the gasket is attached 
to the thermoformed door can readily varied without departing from the 
spirit of the invention. An important aspect of the method of 
manufacturing the refrigerator door as described above is that it enables 
a particular positioning of the joining seam of the outer door panel and 
the refrigerator liner wherein the seam is located in a position where it 
cannot be viewed in the normal door closed posture to provide an 
aesthetically appealing configuration. In general, the invention is only 
intended to be limited by the scope of the following claims.