HK1157002B

HK1157002B - Anti-fog refrigeration door and method of making the same

Info

Publication number: HK1157002B
Application number: HK11111262.5A
Authority: HK
Inventors: 克里斯托弗‧R.‧科丁
Original assignee: 北美Agc平板玻璃公司
Priority date: 2004-09-20
Filing date: 2011-10-20
Publication date: 2014-11-14

Description

Antifogging cold storage door and manufacturing method thereof

The application is a divisional application of an invention patent application with an application number of '200580039612.0' (PCT/US2005/033236) 'anti-fog refrigeration door and a manufacturing method thereof', which is filed on 9/20/2005.

The present patent application claims priority from U.S. provisional patent application No.60/610964 filed on 9/20/2004 and U.S. provisional patent application No.60/700308 filed on 19/7/2005, both of which are hereby incorporated by reference in their entirety.

Technical Field

The present invention relates generally to refrigeration doors, insulated glass units, and refrigeration systems, and more particularly to an anti-fog or anti-frost non-energy consuming refrigeration door that provides condensation control, thermal insulation, and a desired amount of visible light transmittance. More specifically, the refrigeration door of the present invention achieves these desirable features by applying a low-emissivity coating without electrically heating the door and by applying an anti-fog/anti-frost coating or film. In this application, the term "refrigeration door" refers to a door for a refrigerated cabinet, refrigerator, and similar units and cabinets. Additionally, for purposes of this application, the term "non-energy consuming" (e.g., non-energy consuming refrigeration doors) means that electricity need not be applied to the glass to heat the glass. "anti-fog" and "anti-frost" refer to coatings or films that reduce or eliminate clean up time (clearingtime) for a refrigeration door, Insulating Glass Unit (IGU), or other item described herein.

Background

All U.S. patents and U.S. patent application publications referred to herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control.

Refrigeration doors for commercial refrigerated cabinets, refrigerators, and the like are typically constructed of glass to allow customers to see the product disposed therein, thereby eliminating the need to open the door for sale. However, when condensation forms on the glass (sometimes referred to as "fogging"), the customer cannot look through the door to identify the product therein, which is undesirable from the customer's and store owner or retailer's perspective. The formation of frost has similar problems.

Moisture condenses on the outside of the glass refrigeration door because the surface temperature of the outside of the glass drops below the ambient temperature of the store due to the refrigerator refrigerating the freezer or refrigerator interior. Moisture condenses on the surface of the glass as the temperature of the surface of the glass drops below the dew point of the air in the store. In addition, when the door is opened in a humid environment, the innermost glass sheet forming the inside of the door, i.e. the glass sheet, is momentarily exposed to the ambient air of the shop and condensation may also form on the inside of the door. Condensation also occurs on the inside of the glass door because the temperature of the inside of the glass door is below the dew point of the ambient store air to which it is exposed.

As previously mentioned, condensation on the glass, which may be frosted, prevents the customer from seeing the product for sale through the glass door. Therefore, when condensation or frost occurs on the glass door, the customer must perform the cumbersome operation of opening the refrigeration door to identify the contents therein, which is impractical for a store having a large number of refrigerated cabinets or refrigerators. Opening each refrigeration door is not only cumbersome and time consuming for the customer, but is also undesirable for the retailer, as it significantly increases the energy consumption of the retailer's refrigerated cabinet and refrigerator, thus resulting in higher energy costs for the retailer.

There are a variety of different industry performance standards in which refrigeration doors must meet their requirements for acceptance. In the united states, most industries require refrigerated doors (not refrigerator doors) to prevent external condensation when used in an environment having an external temperature of eighty degrees fahrenheit (80F), an external relative humidity of 60%, and an internal temperature of minus forty degrees fahrenheit (-40F). Other countries have different requirements.

As is well known in the art, a conventional refrigeration door includes an Insulated Glass Unit (IGU) housed in a door frame. IGUs in refrigeration doors generally comprise two or three sheets of glass sealed at their peripheries by a sealing assembly generally referred to as an edge seal. In an IGU comprising three sheets of glass, two thermally insulated chambers are formed between the three sheets of glass. In an IGU comprising two sheets of glass, a single insulated chamber is formed. Generally, an IGU for a refrigerator is constructed of two glass sheets, while an IGU for a freezer employs three glass sheets. After being sealed, the chambers are typically filled with an inert gas such as argon, krypton, or other suitable gas to enhance the thermal performance of the IGU.

Most conventional methods of preventing or reducing condensation in a refrigeration door involve providing energy to the door by providing an electrically conductive coating on one or more glass surfaces of the IGU to electrically heat the glass. The purpose of heating the glass is to maintain the temperature of the glass above the dew point of the warmer ambient air of the store. By heating the glass above the dew point, undesirable condensation and frost are prevented from occurring on the glass in the door, so that the interior of the refrigerated compartment can be clearly viewed through the glass.

In a door constructed from a three-layer IGU, the unexposed surface of one or both glass sheets is coated with an electrically conductive material. The conductive coating is connected to a power source by two conductive strips or other electrical connectors mounted on opposite edges of the glass. As current is passed through the coating, the coating heats up, thus heating the glass sheet to provide a condensation-free surface. The coating on the IGU of the refrigeration door is typically applied to the unexposed surface of the outermost glass sheet. However, because condensation sometimes forms on the inside of the glass inner sheet, the unexposed surface of the innermost glass sheet is also coated to heat, thereby preventing condensation.

These conventional heated refrigeration doors of the prior art have several disadvantages and problems. First, heating the door results in energy costs that are higher than and exceed the energy costs of the cooling system. In standard size commercial refrigerated cabinets, the additional cost of heating the cabinet doors is considerable, -based on the current price of electricity, this additional cost can be $100 or more per year per refrigerated cabinet. Given that many stores use multiple refrigerated cases, while some supermarkets and other food retailers use hundreds of refrigerated cases, the cumulative energy costs associated with such heated refrigerated case doors are considerable.

Second, excessive heat from a conventional heated refrigeration door will be transferred to the refrigerated compartment, creating an additional burden on the cooling system, which results in higher energy costs. Third, if the power supplied to the door for heating is too low, the power output is turned off or interrupted and condensation and/or frost will form on the glass. If the power consumption is too high, unnecessary additional energy costs will result. To reduce these problems, such heated glass doors typically require precise control of the door heating system. To achieve the necessary precise control of the door heating system, an electrical control system is required, which results in increased design and manufacturing costs, as well as significant operating and maintenance costs.

Fourth, these electrically heated glass doors can pose a safety hazard to customers and can pose potential risks of liability and exposure to light for retailers and cold storage manufacturers. The voltage applied to the glass door coating was generally 115 volts AC. The shopping carts used by customers in the store are heavy and metallic. If a shopping cart strikes and breaks the glass door, current may be conducted through the cart to the customer, which may result in serious injury or even death to the customer.

U.S. patent nos. 5852284 and 6148563 disclose applying a voltage to glass coated with a conductive coating (which may be a low emissivity coating) to control the formation of condensation on the outside surface of the glass door. Conductive coatings, such as low-emissivity coatings, provide electrical resistance, which generates heat; while also providing the desired thermal characteristics. However, the refrigeration doors disclosed in these patents have the aforementioned drawbacks and problems associated with all electrically heated refrigeration doors. Glass units, doors, refrigeration units, and the like are also disclosed in U.S. patent nos. 6367223, 6606832, and 6606833. These and other U.S. patents and patent applications are incorporated by reference in their entirety as if fully set forth herein.

In addition to being used for electrical conduction, such low-emissivity coatings have been applied as another measure for reducing condensation on refrigeration doors. In particular, one way to increase the thermal insulation value ("R-value") of the glass and reduce heat loss from the refrigerated compartment is to apply a low emissivity (low E) coating to the glass. The low E coating is a microscopic thin, substantially invisible metal or metal oxide layer deposited on the glass surface to reduce emissivity by suppressing radiant heat flow through the glass. Emissivity is the ratio of the amount of radiation emitted by a black body or surface to the theoretical amount of radiation predicted by planck's law. The term "emissivity" refers to emissivity values measured in the infrared range according to the American Society for Testing and Materials (ASTM) standards. Emissivity is measured using an emissivity measuring device and reported as hemispherical emissivity (hemispherical emissivity) and standard emissivity (normal emissivity). Emissivity indicates the percentage of long infrared wavelength radiation emitted by the coating. A lower emissivity indicates that less heat will be transferred through the glass. Thus, the emissivity of the glass sheet or IGU affects the thermal insulation value of the glass or IGU as well as the thermal conductivity ("U value") of the glass or IGU. The U value of a glass sheet or IGU is inversely proportional to its R value.

In a multi-layer IGU, the emissivity of the IGU, i.e., the combined emissivity of the individual glass sheets forming the IGU, can be estimated by multiplying the emissivity of all the glass sheets together. For example, in a two-layer IGU, where each glass sheet has an emissivity of 0.5, the total emissivity would be 0.5 times 0.5 or 0.25.

While low E coatings have been applied to IGUs used in refrigeration doors that require and do not require electrical heating of the door, such coatings and IGUs are not suitable for controlling condensation and providing the required insulation in a wide temperature range and environment where such refrigeration doors are utilized without the application of electricity to heat the door. More specifically, despite the use of such low E coatings, refrigeration doors that are not heated do not provide condensation control in applications where the interior temperature of the refrigerated compartment is substantially near or below freezing.

Furthermore, conventional anti-fog/anti-frost coatings, films, and the like, as well as methods of coating them, also have limitations. For example, the film may still allow the formation of water droplets that appear to be a fog and hazy scene. Also, after brief water immersion or repeated cleaning, the anti-fog properties are often lost. Moreover, known antifog articles that function by absorbing condensation can saturate and fail in a very humid state, at least in part due to their highly expanded state. Also, these articles can be easily scratched or soiled and are not sufficiently tolerant or resistant to common solvents. In addition, conventional antifog articles can suffer from common coating problems such as dripping, drooling, trapping dust, and chemical cracking.

Thus, while electrically heated and low-emissivity coated refrigeration doors may be employed, as well as anti-fog and anti-frost articles such as films and coatings, there is a need for refrigeration doors that: (1) provide the necessary condensation control and thermal insulation over a wide range of temperatures and environments; (2) has a desired amount of visible light transmittance; (3) avoiding unnecessary energy costs and excessive burdens on the cooling system by reducing the need to supply electrical energy to heat the doors; (4) no need for expensive and complex electrical control systems, thereby minimizing design, manufacturing, operation, and maintenance costs; and (5) do not pose a safety hazard to customers and the potential for liability and exposure to manufacturers and retailers, and otherwise overcome or reduce the above-described problems.

Disclosure of Invention

It is an object of the present invention to overcome the above-described deficiencies in the prior art by providing condensation control, thermal insulation and a desired amount of visible light transmission for a non-energy consuming refrigeration door.

It is another object of the present invention to provide a refrigeration door that does not utilize electrical energy to reduce condensation on the glass.

It is another object of the present invention to provide a refrigeration door that controls condensation and does not transfer significant amounts of heat to the interior of the refrigerated cabinet or refrigerator, thus not further burdening the cooling system and not increasing energy costs.

It is another object of the present invention to provide a condensation controllable refrigeration door that is easier and more economical to manufacture, operate and maintain than prior art refrigeration doors and systems.

It is another object of the present invention to provide a refrigeration door with controlled condensation that is easier to design, operate and maintain.

It is another object of the present invention to provide a method of manufacturing a condensation controllable refrigeration door that does not utilize electrical energy to heat the glass to control condensation.

It is another object of the present invention to provide a refrigeration door having an emissivity of less than 0.04.

It is another object of the present invention to provide a refrigeration door having an emissivity of about 0.0025.

It is another object of the present invention to provide a refrigeration door having a U value of less than 0.2BTU/hr-sq ft-F.

It is another object of the present invention to provide a refrigeration door having a U value of about 0.16BTU/hr-sq ft-F.

It is another object of the present invention to provide a refrigeration door having additional anti-fog and anti-frost properties that reduce the clean-up time to zero or near zero.

Other objects include providing an anti-fog or anti-frost coating or film for use in a refrigeration door, and refrigeration systems and IGUs that include such a film on a substrate surface.

The present invention accomplishes these and other objects by providing, among other things, a non-energy consuming refrigeration door and a method of making the same. In one aspect, the invention includes a door frame that houses an insulating glazing unit, wherein the insulating glazing unit includes an inner pane of glass, an intermediate pane of glass, and an outer pane of glass. A first seal assembly disposed around the periphery of the glass inner sheet and the glass intermediate sheet forms a first chamber between the glass inner sheet and the glass intermediate sheet. A second seal assembly disposed around the periphery of the glass center sheet and the glass outer sheet forms a second chamber between the glass center sheet and the glass outer sheet. A gas such as krypton, air or argon is maintained within the first and second chambers. The glass outer sheet and the glass inner sheet each have an unexposed surface facing the glass intermediate sheet. The low emissivity coating is disposed on the unexposed surfaces of the glass inner and outer sheets such that the glass door as a whole has a U value that prevents condensation from forming on the outer surface of the glass outer sheet of the door without the application of electricity to heat the door, while also providing a desired rate of evaporation of condensate from the inner side of the glass outer sheet of the door. An anti-fog/anti-frost coating or film is disposed on a surface of one of the glass sheets, preferably on the exposed surface of the inner sheet.

In one aspect, the present invention also provides novel anti-fog/anti-frost coatings.

Antifog/antifog coatings are used in a variety of different applications, such as insulating glass units, including those with multiple layers, refrigeration and cold storage doors for refrigeration and cold storage display cases, automotive reflectors, special exterior mirrors, saunas, steam rooms, shower doors, ticket windows, bathroom mirrors, exterior cooling units, and refrigerated cabinets exposed to high humidity or rain, and any other application where an antifog or antifog coating/film is desired. Thus, while the anti-fog/anti-frost coatings of the present invention are preferred for use with non-energy consuming refrigeration and cold-storage doors, they are also suitable for a variety of other applications, including doors to which energy is applied, such as electrically heated doors.

Further features and advantages of the invention, as well as the structure and operation of various embodiments of the invention, are described in detail below with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate various embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. In the drawings, like reference numbers can indicate identical or functionally similar elements.

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 illustrates a refrigeration system employing an embodiment according to the present invention;

FIG. 2 illustrates a refrigeration door according to the present invention;

FIG. 3 shows a partial cross-sectional view of a refrigeration door according to the present invention;

figure 4 shows a partial cross-sectional view of a refrigeration door according to the present invention.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as the particular coatings, coating processes, sheet and film thicknesses, seal assemblies, number of sheets, sheet spacing, and methods of assembling the door, in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. Descriptions of well-known coatings, coating processes, seal assemblies, and methods of assembling doors are omitted so as not to obscure the description of the present invention. For the purposes of describing the present invention, terms such as exterior, interior, exterior and interior are described in terms of perspective from the inside of the refrigerated cabinet or compartment, as shown in the figures.

Testing and computer modeling have demonstrated that a U value (thermal conductivity of the glass) of about 0.2BTU/hr-sq ft-F is required for a refrigeration door to prevent condensation on the outside of the glass, under the performance requirements of the U.S. industry as described above. However, as noted, when the door is opened, condensation can form on the inside of the glass inside sheet of the door because the inside surface of the sheet is at a temperature below the dew point of the more humid ambient store air to which the inside surface is exposed. However, after the door is closed, condensation will dissipate as moisture evaporates into the refrigerated cabinet or compartment.

When condensation occurs on the inside of the door, the contents of the freezer or refrigerator are not visible through the door. Therefore, the evaporation rate, the length of time it determines when condensation occurs (also referred to as "clean up time"), is an important design criterion. The more heat that is transferred through the glass door to the inside surface of the glass door, the faster the condensation evaporates on the inside of the door. However, the increased heat transfer via the door also results in increased energy costs for the cooling system. Thus, the optimal U-value for a glass door is determined by a number of factors, including the inside and outside temperature differences, the glass thickness, the spacing, the gases used in the IGU's chamber, the number of sheets, the spacer material, the ambient humidity, the absorption coefficient of the far infrared spectrum of the coating, and the desired time for condensation to evaporate. In addition, costs associated with selected components (i.e., gas, seal assembly, glass, etc.), energy costs, and other factors are also considered in the design. The preferred embodiment described below provides a U value of 0.16BTU/hr-sq ft-F that prevents condensation on the outside of the door while allowing sufficient heat from the outside environment to penetrate the door to allow condensation on the inside of the door to evaporate in a reasonable amount of time. Some refrigeration system manufacturers require that the condensate evaporate within a few minutes, while others require that it evaporate within a minute. In alternative embodiments, the U value may be approximately equal to or less than 0.16BTU/hr-sq ft-F. The time required for the condensate to evaporate will vary depending on the amount of time the door is open, the humidity in the store, the refrigeration system compartment temperature, the refrigeration system contents, the amount of heat transferred through the door (which depends on the U value), and other factors.

In an embodiment of the present invention, as shown in FIG. 1, the refrigeration system 5 includes a plurality of transparent refrigeration doors 10, each having a handle 11. As described in greater detail below, each refrigeration door 10 includes an IGU 50 mounted in a frame 55. The interior of the refrigeration system includes a plurality of shelves 6 for holding the goods visible through the door. Referring to fig. 2, the refrigeration door 10 of the present embodiment is mounted to an opening of the refrigeration system by a hinge that allows the door to open outwardly.

As described above, the refrigeration door 10 includes the IGU 50 housed in the frame 55. As shown in fig. 3, IGU 50 includes an outer sheet of glass 60, an intermediate sheet of glass 65, and an inner sheet of glass 70. IGU 50 is housed in frame 55 and further includes a first seal assembly 90 extending around the perimeter of inner side surface 60 of outer sheet 60 and the outer side surface of glass intermediate sheet 65 to define a substantially hermetically sealed, insulated outer chamber 92. Similarly, a second seal 95 extends around the periphery of the outer side surface 72 of the glass inner sheet 70 and the inner side surface of the glass intermediate sheet 65 to define a substantially hermetically sealed, thermally insulating interior chamber 94.

The outer surface 61 of the glass outer sheet 60 is positioned adjacent to the external environment 7. In other words, the outside surface 61 of the outside sheet 60 is exposed to the environment in which the refrigerator or freezer is located. The inside surface 62 of the outside sheet 60 forms a part of the outer chamber 92 and is exposed thereto.

In the preferred embodiment, outer sheet 60 is one-eighth inch thick and is tempered, while the inside surface 62 of outer sheet 60 is coated with a low-e coating 63. In particular, in this embodiment, the low E coating is a sputter-coated low E coating comprising ultra-hard titanium oxide as a base layer to ensure a high level of thermal performance and high visible light transmission. This particular sputter coated glass is tempered after coating and provides high visible light transmission without high tint levels. The outside surface 61 of the outside sheet 60 is not coated. In this embodiment, outer sheet 60 may be, for example and without limitation, a Comfort Ti-PS glass sheet having a thickness of one-eighth inch manufactured by AFG industries, Inc. of Kingsport, Tennessee, with a low E coating that provides an emissivity of 0.05. As is well known in the art, Comfort Ti-PS is cut to size, tempered, and edge processed prior to integration into the IGU 50. The low-E glass referred to herein is not limited to the specific name given above, but may be any suitable low-E glass, including, but not limited to, sputter-coated and pyrolytic coated (pyrolytically coated) low-E glass.

Glass middle sheet 65 is positioned between glass outer sheet 60 and glass inner sheet 70 and forms a portion of outer chamber 92 and inner chamber 94. Middle sheet 65 is spaced one-half inch from outer sheet 60 and inner sheet 70 and is an one-eighth inch thick, uncoated, tempered glass sheet.

A glass inner sheet 70 is positioned adjacent the interior of the refrigerated cabinet or compartment 9 with its inner surface 71 exposed to the interior of the compartment 9. The outer side surface 72 of the inner sheet 70 forms a portion of the interior chamber 94 and is exposed thereto. The outside surface 72 of the glass inner sheet 70 is also coated with a low emissivity coating 73. In this embodiment, the coating 73 on the outside surface 72 of the inside sheet 70 is the same as described above for the coating 63 on the inside surface 62 of the outside sheet 60. In a preferred embodiment, inside surface 71 is coated with an anti-fog or anti-frost coating or film 75 that significantly reduces the clean-up time during unit operation, preferably to substantially zero (i.e., no visible fog is present).

Preferred antifog coatings or films include those known in the art from FilmOf Specialties corporationAndan antifogging film. These films may include optical adhesive on opposite sides for ease of installation. For example, Vistex includes a polymer cured on a transparent polyester film with an optically clear adhesive on the opposite side. Vistex andmay be purchased as a plastic film or liquid. These films eliminate fogging in all temperature-humidity states. Furthermore, fog and condensate formation is prevented even when the refrigerator or freezer door has been supported open for extended periods, for example during restocking. After a brief water immersion or repeated cleaning, the anti-fog properties are not lost, nor are the coatings saturated or ineffective in very humid conditions, such as those that work by absorbing condensation. The preferred antifog film used in the present invention is hydrophilic so that moisture spreads out on the surface of the coating in an invisible floor layer rather than forming water droplets that appear to be a fog and hazy scene. Also, preferred films are scratch resistant and include an acrylic adhesive on the opposite side. The binder is of the type commonly used on solar control films and allows the film to be applied to any flat or cylindrical surface. The adhesive system may be pressure sensitive or detackified pressure sensitive, both of which are optically clear. Different film thicknesses may be used and one skilled in the art will readily determine the appropriate thickness for the desired application. The preferred thickness is 4 mils. The film may be mounted on the glass surface using a squeegee.

Preferred films are permanent antifog or antifrost films based on hydrophilic polymer technology. The anti-fog/anti-frost coating operates by reducing the surface tension of the water while allowing the condensate sheet to unfold, thus eliminating fogging at all temperature and humidity conditions. Preferred coatings tolerate a much greater number of processing disadvantages than most untreated plastics. The slight surface scratches that appear in the antifogging film will actually repair themselves when exposed to moisture. Moreover, preferred coatings have a high degree of chemical resistance and will be resistant to solvents such as isopropanol, toluene or acetone, thus protecting the substrate from attack by the solvent. If necessary, a common glass cleaner can be used.

Preferred films are poorly soluble in water and, in contrast to other anti-fog coatings known in the art, will not smudge or dissolve when wet. The preferred films cure in a controlled state, thus eliminating common coating problems such as dripping, drooling, trapped dust, and chemical cracking. Moreover, the film adds scratch resistance and a measure of resistance to chipping to the glass to which it is applied. The adhesive will bond to glass or any plastic, even hard surfaces treated to resist scratching.

With certain well-known anti-fog and anti-frost films/coatings suitable for use in embodiments of the present invention, the cured primer is applied to the glass prior to application of the anti-fog or anti-frost film. Conventional coatingA100: 40 mix ratio containing "part A" and "part B" chemicals as described above is known and commercially available from Film Specialities, Inc.Part A ingredients included diacetone alcohol (46%), N-methylPyrrolidone (4%), t-butanol (4%), Cyclohexane (8%), 2, 4-pentanedione (2, 4-pentanedione) (6%), and Aromatic150 (2%).Part B of the composition comprised polyisocyanate (66%), free monomeric isocyanate (1%), xylene (11%), n-butyl acetate (11%) and toluene (11%). As is pointed out in the above-mentioned manner,the part a and part B ingredients are readily available to the public. Furthermore, known membranes generally contain additional solvents, such as additional amounts of diacetone alcohol and tertiary butanol (tertiary butyl alcohol), in order to dilute the mixture. Moreover, the process of making known films often involves the need for two separate coating steps and two curing cycles. Cure time, temperature, and method can have a significant impact on anti-fog and anti-frost properties. For example, overcuring will significantly reduce these characteristics. Forced convection is the slowest method and is more likely to result in a thin skin (thin-skin) of the over-cured coating while compromising the anti-fog and/or anti-frost properties. Radiant energy is a fast and efficient method to avoid over-curing.

Some suitable coatings, films, and aspects thereof are disclosed in U.S. Pat. Nos. 4467073, 5262475, and 5877254, and U.S. patent application publications US2003/0205059A1, US2005/0064101, US2005/0064173, and US2005/0100730, which are hereby incorporated by reference in their entirety. These and other patents and patent applications, and the specification set forth herein, provide those skilled in the art with a sufficient guidance to practice the invention with ease.

However, the present invention also provides novel anti-fog and anti-frost coatings/films having improved properties over the above and other known films. The present invention also provides novel processes for making and coating such improved films. For example, it has been surprisingly found that a mixture of part a and part B chemicals (described above and B) in a ratio of approximately 100 units of part a to approximately 25 to 45 units of part BRelated) produces improved antifog and antifrost results over known films. A lower amount of part B ingredient (which acts as a hardener) within the above range improves the anti-fog properties of the film while maintaining scratch resistance. Using a higher percentageThe component B of the ratio can obtain good antifogging property. In a preferred embodiment, the ratio is about 100 units of part a composition to about 30 to 33 units of part B composition. In a particularly preferred embodiment, the ratio is a ratio of about 100 units of portion a to about 30 units of portion B.

It has also been surprisingly found that the elimination of the use of additional solvents, such as additional diacetone alcohol and tert-butanol (specifically the elimination of additional diacetone alcohol), improves the anti-fog and/or anti-frost properties. The elimination of these solvents particularly improves the anti-frost properties. However, the addition of at least one such solvent, tertiary butanol, has been found not to hinder the anti-frost properties. Further, in embodiments of the present invention, the cured primer generally included in the aforementioned known films has been eliminated by pretreating the glass substrate with a silane and adding a different silane to the anti-fog/anti-frost mixture. For example, silane pre-treatment may help the polymer coating adhere to the substrate under extreme chemical conditions or under long term wet immersion. In a preferred embodiment, the silane added to the mixture is 3-glycidoxypropyltrimethoxysilane (3-glycidoxypropyl methoxysilane). It has been surprisingly found that the inclusion of the silane increases abrasion resistance (i.e., scratch resistance) and promotes adhesion and weatherability. 3-Oxypropyleneoxy trimethoxysilane does not promote yellowing of the film as does some silanes. In a preferred embodiment, 3-glycidoxypropyltrimethoxysilane is present in an amount of about 1% to about 8%, more preferably about 6%. Other silane additives may also be used with similar effects. Furthermore, other suitable additives and primers are such that they promote adhesion of the polyurethane to inorganic components such as glass. These materials include, but are not limited to, polymers having an affinity for glass.

The invention also provides novel processes for making and coating the above-described films. In one aspect, the present invention provides a method wherein the coating step can be reduced to a single coating and a single curing cycle. This reduces the chance of damaging effects of over-curing, among other advantages. Further, in embodiments of the present invention, the coating or film is applied using a curtain coater. Adjustments are made to prevent excessive reynolds numbers in the curtain to avoid semi-turbulent and turbulent conditions. For example, in an embodiment, a standard weir-type curtain coater (standard wire-type coater) may be adjusted to give the desired laminar flow. Such adjustment may include limiting the size of the weir lip (weirlip) to prevent semi-turbulent conditions.

In an alternative embodiment, the substrate, preferably glass, may be pre-treated with silane, preferably Silquest A-1106 amino alkyl silicone, to promote wetting and adhesion. The specific silane was applied by mixing approximately 1% silane in the rinse water of the glass washer. This process eliminates some of the additional steps required in the prior art processes. Thus, while some anti-fog and anti-frost coatings or films are known and may be used in conjunction with other aspects of the invention described herein, the present invention also provides novel anti-fog and anti-frost coatings/films having improved characteristics over those previously seen in the art, and provides novel processes for making and applying them. In embodiments, the present invention provides anti-fog and anti-frost films/coatings having a tailored ratio of part a to part B chemicals in the mixture (as described above); and provides coatings/films that do not include the particular commonly used solvents. Also, in embodiments of the present invention, the properties of the film may be improved by adjusting the curing cycle. The substrate may also be pretreated to promote wetting and adhesion.

Thus, in one aspect, the present invention provides a polymer composition having anti-fog and anti-frost forming properties after drying or curing. In a preferred embodiment, the composition includes a chemical mixing ratio of part a to part B chemicals (described herein) of about 100: 40 and does not include a solvent, diluent, or cured primer applied to the glass substrate. In an alternative embodiment, the mixture includes a silane, preferably 3-glycidoxypropyltrimethoxysilane. Preferred compositions promote scratch resistance, adhesion, and weatherability.

In another aspect, the present invention provides a refrigeration door comprising a substantially transparent substrate having an anti-fog or anti-frost coating on at least a portion of the substrate that is substantially non-fogging or frosting when the portion has an initial surface temperature and is then exposed to humid ambient air for a period of time, wherein the dew point temperature is at or above the surface temperature. The surface temperature may be below about 0 ℃ and this time may be as large as 6 seconds or more.

The present invention also provides a method of manufacturing a refrigeration door having a substantially transparent substrate, the method comprising forming an anti-fog or anti-frost coating as described herein on at least a portion of the substrate, wherein the substrate is a portion of, or is used to manufacture, a refrigeration door. In one embodiment, the method includes mixing part a and part B chemicals to form a mixture, applying the mixture to at least a portion of the substrate, and curing the substrate. The present invention also provides an IGU comprising a substrate having an anti-fog or anti-frost coating on at least a portion of the substrate, as described herein; a refrigeration door including the IGU; a refrigeration system comprising the refrigeration door. Moreover, in other embodiments, the present invention provides a refrigeration door comprising a substantially transparent substrate having a coating on at least a portion of the substrate, the coating inhibiting condensation of water on the portion maintained at a temperature of about-28 ℃ when the portion is exposed to an environment at a temperature of about 25 ℃ for up to 12 seconds or more. This prevention of condensation water droplets results in the prevention of the formation of scattered light mist or frost.

In the embodiment shown in FIG. 3, inner sheet 70 may also be, for example, but not limited to, a Comfort Ti-PS sheet having a thickness of one-eighth of an inch, manufactured by AFG industries, Inc., with desired properties and coatings.

In the exemplary embodiment, both chambers 92 and 94 are filled with air. In alternative embodiments, each chamber may be filled with the same or different gas, and the chambers may be filled with krypton, argon, or other suitable gas.

The sheets 60, 65 are held apart by a first sealing assembly 90 which extends around the periphery of the sheets 60, 65, maintains the glass sheets in a parallel, spaced apart manner, forming a chamber 92 between the sheets 60, 65, while also sealing the chamber 92 from the external environment. Likewise, the sheets 65, 70 are held apart by a second sealing assembly 95 which extends around the periphery of the sheets 65, 70, maintains the glass sheets in a parallel, spaced apart manner, forming a chamber 94 between the sheets 65, 70, while also sealing the chamber 94 from the external environment. The seal assemblies 90, 95 maintain a one-half inch spacing between the outer sheet 60 and the middle sheet 65 and between the inner sheet 70 and the middle sheet 65, respectively.

The seal assemblies 90, 95 of this embodiment are preferably warm-edge seals. "Warm edge" is used to describe an insulating glass seal assembly that reduces heat loss better than conventional aluminum spacer blocks and seal assemblies. Each seal assembly 90, 95 of this embodiment includes its own spacer and desiccant, which replaces the need for a separate sealant, metal spacer and desiccant; and has a heat transfer rate (sometimes referred to as a K value) of 0.84 Btu/hr-ft-F. The seal assemblies 90, 95 in this embodiment are co-extruded shapes that include a combination of polyisobutylene sealant, hot melt butyl sealant, desiccant matrix, rubber gasket, and evaporation barrier (vapor barrier). A suitable Seal assembly of this type is manufactured and sold by TruSeal technologies, Inc. of Beachwood, Ohio under the trade designation "Comfort Seal".

Referring to fig. 3, an IGU 50 is shown. IGU 50 includes glass sheets 60, 65, and 70, which are integrated by seal assemblies 90 and 95. IGU 50 is mounted in frame 55 in any suitable manner known to those skilled in the art. The frame 55 is made of extruded plastic or other suitable known frame materials such as extruded aluminum, fiberglass or other materials. In an alternative embodiment, if the frame 55 is formed of aluminum or other material, the door needs to be heated along its edges to ensure condensation control near the edges of the door.

Referring to fig. 1, a refrigeration system 5 is shown. The door frame 55 is connected to the refrigerated compartment 8 in any suitable manner known in the art, such as a single door long hinge, multiple hinges or slots for sliding door opening and closing. In addition, the frame may include a door handle 11 or other suitable operating means suitable for the application. The refrigeration system 5 of which door 10 forms a part may be any system for cooling a compartment, such as that disclosed in U.S. patent publication No.6148563, which is incorporated herein by reference.

The preferred embodiment described above provides a refrigeration door having a U value of 0.16BTU/hr-sq ft-F (and an emissivity of 0.0025), which has been found to be suitable for use in refrigeration cabinet door applications requiring the performance standards specified above for the United states industry. A U value of 0.16BTU/hr-sq ft-F allows the refrigeration door to easily meet required performance standards while still allowing sufficient heat to penetrate the door and the outside environment to evaporate the condensate formed on the inside of the door in a reasonable period of time. In addition, the preferred embodiment provides sixty-six percent (66%) visible light transmission. In the preferred embodiment described above, wherein this embodiment includes the described anti-fog/anti-frost coating or film, no fog or frost formation is observed on the glass.

As an alternative to Comfort Ti-PS glass, other low E coated glasses may be used, such as Comfort Ti-R, Comfort Ti-AC, Comfort Ti-RTC, and Comfort Ti-ACTC, all available from AFG industries, Inc., which like Comfort Ti-PS are titanium oxide/silver based low E coated glasses manufactured by AFG industries, Inc. Another suitable type of glass is Comfort E2, which is coated using a thermal decomposition process and is fluorine doped tin oxide low E coated glass, one-eighth inch thick, and manufactured by AFG industries. Comfort E2 is suitable for some relaxed performance criteria due to its higher emissivity. The low-E glass referred to herein is not limited to the article specifically named above, but can be any suitable low-E glass, including, but not limited to, those named above, as well as other sputter-coated and thermally-decomposition-coated low-E glasses.

The U value of the refrigeration door 10 is determined by a number of design factors including the number of sheets of glass, the thickness of the sheets, the emissivity of the IGU, the spacing between the sheets, and the gas within the compartment. In the three-layer refrigeration door 10 of the preferred embodiment described above, using air as the gas to be maintained within the room, a U value of 0.16BTU/hr-sq ft-F, a glass thickness of one-eighth inch, a one-half inch spacing, and an IGU emissivity of 0.0025 on all sheets is achieved. Each of these factors can then be varied, which results in a variety of permutations of values that can be combined to provide the same U value. In addition, other applications require smaller or larger values of U, depending on the environment, cost constraints, and other needs and considerations.

A number of computer simulations have been performed to determine U values for a plurality of IGUs in the refrigeration door 10 using a range of values for each of the different design parameters incorporated in the different arrangements. The following table includes design parameters for a plurality of three-layer IGU structures and corresponding calculated U values. In addition to the design parameters listed in table 1, the calculated values for the U values for all three-layer IGUs were calculated in such a case that each sheet was one-eighth inch thick and all two sides of the three layers were coated with low E. Tempering of the glass does not significantly affect the calculated property values. Moreover, the addition of an anti-fog/anti-frost coating or film according to the present invention does not significantly affect these values.

TABLE 1

In each of the tables included herein, "Ti-PS" refers to the low E coating of ComfortTi-PS glass by AFG industries, Inc., and "CE 2" refers to the low E coating of ComfortE2 glass by AFG industries, Inc., both as described above. In addition, the U values in the tables are calculated as "glass center" values because computer simulations cannot account for the seal assembly. Thus, no seal assembly data or design criteria are listed in the table.

In an alternative two-layer embodiment of the invention shown in fig. 4, IGU 50 includes glass outer sheet 60 and glass inner sheet 70, frame 55, and seal assembly 90. In this two layer embodiment, both outer sheet 60 and inner sheet 70 are one-eighth of an inch thick and include the same low E coating as described in the first embodiment, which is a titanium oxide based silver low E coating. Additionally, for example, both outer sheet 60 and inner sheet 70 may be Comfort Ti-PS glass sheets, one-eighth inch thick, manufactured by AFG industries, Inc. The coated sides of sheets 60 and 70 are sides 62 and 72, respectively, which are located on the unexposed surfaces of the sheets, forming a portion of chamber 92. Additionally, the same sealing assembly 90(Comfort Seal) as described above may be used and is used to provide a one-half inch spacing between glass outer sheet 60 and glass inner sheet 70. In addition, an anti-fog/anti-frost coating or film 75 is disposed on the exposed surface 71 of the inner sheet 70.

Table 2 below includes design parameters for a plurality of two-layer IGUs and corresponding calculated U values. The calculated values for all two layers were calculated in such a case that each sheet was one eighth inch thick and both sides of the two layers were coated with low E, except for the design parameters listed in the table below. Tempering of the glass does not significantly affect the calculated performance values, nor does the addition of the anti-fog/anti-frost coating or film described herein.

TABLE 2

In alternative embodiments, any suitable type of coating process for low-E coatings may be employed, including thermal decomposition (e.g., in Comfort E2), which is often referred to as chemical evaporation (CVD); spraying; sputter coating (e.g., in Comfort Ti-PS). Furthermore, these processes may be applied using well-known off-line or on-line manufacturing methods, wherein the methods are adapted and adapted to the quality and type of specific production and processing. Likewise, any suitable low E coating may be used, including silver-based or fluorine-doped tin oxide coatings.

Although the embodiments described above include a low E coating on the unexposed surfaces of both glass sheets, other embodiments of the invention may include a low E coating applied only to either or both sides of one glass sheet. Likewise, in other embodiments, the glass middle sheet (three layer embodiment) may include a low E coating on either side (or both sides) instead of, or in addition to, coatings on glass inner sheet 70 and glass outer sheet 60.

In another three-layer embodiment, there is no low E coating on either side of glass inner sheet 70. Also, in an alternative to the two-layer embodiment described above, the low E coating is present on only one sheet, or on both sides of both sheets. In general, the number of layers with low E coating and the side (or sides) with coating are design choices. The total emissivity of the IGU, which among other factors determines the U value of the door, is more important for thermal performance than the coated side of the sheet. Additionally, while the embodiments described herein have an emissivity less than or equal to 0.04 for refrigeration door applications, the use of high performance gases (such as krypton) may allow the IGU to have an emissivity slightly greater than 0.04 to provide the necessary condensation control in some cases.

In other embodiments, other sealed assemblies may be employed, including, for example, full foam, non-metallic assemblies, such as Super Spacer manufactured by EdgeTech corporation, having a heat transfer rate of approximately 1.51 Btu/hr-ft-F. Another suitable seal assembly is a thermo plastics Spacersystem manufactured by Lenhardt Maschinenbau GmbH, which has a heat transfer rate of approximately 1.73 Btu/hr-ft-F.

The spacing in the above embodiment is one-half inch. However, while the preferred range of spacing is between five sixths of an inch and one half inch, other embodiments of the invention may use spacing up to three quarters of an inch. Additionally, while the embodiments disclosed above employ one-eighth inch thick, tempered glass (except for the intermediate sheet), other embodiments may employ untempered glass, or may be thicker or thinner than one-eighth inch.

The design parameters of an embodiment of the present invention will be determined, in part, by the application or intended use of the embodiment. More specifically, the external ambient temperature, the internal temperature, and the external ambient humidity (and associated dew point) are important factors in determining the necessary U value for the design, which in turn determines the design parameters (type of glass, emissivity, number of sheets, gases, etc.).

The left five columns of table 3 below provide a list of calculated U values for the different applications to be used and include the outside temperature, the inside temperature, the outside humidity, and the calculated dew point for each U value. In addition, the right three columns of table 3 provide an embodiment of the present invention that sets the necessary U values.

TABLE 3

The design parameters of table 3 indicate the type of glass (one-eighth inch thick), the spacing between the sheets, and the gas in each chamber. Additionally, all IGUs of table 3 include a third, uncoated glass sheet that is one-eighth of an inch thick and is positioned between the two glass sheets identified in the table. CE1 in Table 3 refers to Comfort E1, which has an emissivity of 0.35 and is sold by AFG industries.

Thus, in one aspect, the present invention provides a refrigeration door suitable for use in a refrigeration compartment, the door comprising a glass inner sheet comprising a first surface and a second surface, the first surface of the inner sheet being disposed adjacent the interior of the refrigeration compartment; a glass outer sheet comprising a first surface and a second surface, the first surface of the outer sheet disposed adjacent to an exterior environment of a refrigerated compartment; a glass middle sheet located between the glass inner sheet and the glass outer sheet; a first seal assembly disposed about the periphery of the glass inner sheet and the glass intermediate sheet so as to maintain the inner sheet and the intermediate sheet in a spaced apart relationship from one another; a second sealing assembly disposed about the periphery of the glass middle sheet and the glass outer sheet so as to maintain the middle sheet and the outer sheet in a spaced apart relationship from one another; a first low-e coating adjacent to the second surface of the inner sheet of glass; a second low-E coating adjacent to a second surface of said glass outer sheet, wherein said inner sheet, outer sheet, intermediate sheet, first sealing assembly, second sealing assembly, and said first and second low-E coatings form an insulating glass unit having a U value substantially equal to or less than 0.2BTU/hr-sq ft-F, substantially preventing the formation of condensation on said first surface of said glass outer sheet without the application of electricity to heat said first surface of said glass outer sheet; an anti-fog or anti-frost coating on a surface of the inner sheet; and a frame secured around a periphery of the insulating glass unit.

The present invention also provides a refrigeration door adapted for use in a refrigeration compartment, the door comprising a glass inner sheet comprising a first surface and a second surface, the first surface of the inner sheet being disposed adjacent the interior of the refrigeration compartment; a glass outer sheet comprising a first surface and a second surface, the first surface of the outer sheet disposed adjacent to an exterior environment of a refrigerated compartment; a glass middle sheet located between the glass inner sheet and the glass outer sheet; a first seal assembly disposed about the periphery of the glass inner sheet and the glass intermediate sheet so as to maintain the inner sheet and the intermediate sheet in a spaced apart relationship from one another; a second sealing assembly disposed about the periphery of the glass middle sheet and the glass outer sheet so as to maintain the middle sheet and the outer sheet in a spaced apart relationship from one another; a first low-e coating adjacent to the second surface of the inner sheet of glass; a second low-e coating adjacent to the second surface of the glass outer sheet, wherein the inner sheet, outer sheet, intermediate sheet, first sealing assembly, second sealing assembly, and the first and second low-e coatings form an insulating glass unit having an emissivity equal to or less than 0.04 that substantially prevents condensation formation on the first surface of the glass outer sheet without the application of electricity to heat the first surface of the glass outer sheet; an anti-fog or anti-frost coating on a surface of the inner sheet; and a frame secured around a periphery of the insulating glass unit.

In various embodiments, the interior temperature of the refrigerated compartment is approximately equal to or less than minus twenty degrees fahrenheit; the temperature of the external environment is approximately equal to or greater than seventy degrees Fahrenheit; and the humidity of the external environment is approximately equal to or greater than sixty percent, the first surface of the glass outer sheet is substantially free of condensation and no fog or frost is formed on the inner sheet.

In other embodiments, the interior temperature of the refrigerated compartment is approximately equal to or less than zero degrees fahrenheit, the temperature of the exterior environment is approximately equal to or greater than seventy-two degrees fahrenheit, and the humidity of the ambient environment is approximately equal to or greater than sixty percent, the first surface of the glass outer sheet is substantially free of condensation, and there is no fog or frost formation on the inner sheet.

The present invention also provides a refrigeration door (and IGU, and refrigeration systems including the same) having an exterior surface and adapted for use in a refrigerated compartment, the door comprising a first sheet of glass; a second glass sheet; a first seal assembly disposed about a periphery of the first and second sheets of glass so as to maintain the first and second sheets in a spaced apart relationship from one another; a first low-E coating adjacent to a surface of the first or second glass sheets, wherein the first and second glass sheets, the first sealing assembly, and the first low-E coating form an insulating glass unit having a U value substantially equal to or less than 0.2BTU/hr-sq ft-F; an anti-fog or anti-frost coating on a surface of one sheet; and a frame secured around a periphery of the insulating glass unit.

The present invention also provides a refrigeration door (and IGU, and refrigeration systems including the same) having an exterior surface and adapted for use in a refrigerated compartment, the door comprising a first sheet of glass; a second glass sheet; a first seal assembly disposed about a periphery of the first and second sheets of glass so as to maintain the first and second sheets in a spaced apart relationship from one another; a first low-e coating adjacent to a surface of the first or second glass sheets, wherein the first and second glass sheets, the first sealing assembly, and the first low-e coating form an insulating glass unit having an emissivity equal to or less than 0.04; an anti-fog or anti-frost coating on a surface of one sheet; and a frame secured around a periphery of the insulating glass unit.

The present invention also provides a method of manufacturing a refrigeration door component having an outer side surface, wherein the method comprises the steps of, providing a first sheet of glass; providing a second glass sheet; providing a first low-e coating adjacent to a surface of the first or second glass sheet; disposing a first sealing assembly around a periphery of the first and second glass sheets to maintain the first and second sheets in a spaced apart relationship from one another; providing an anti-fog or anti-frost coating on one of the glass sheets; and wherein said first sheet of glass, said second sheet of glass, and said first sealing assembly form an insulating glass unit having a U value substantially equal to or less than 0.2BTU/hr-sq ft-F, substantially preventing the formation of condensation on the outside surface of the refrigeration door component without the application of electricity to heat the door component, and substantially preventing the formation of fog or frost on the surface of the component. In an alternative embodiment, the method includes providing a third sheet of glass, which may include a low-E coating adjacent at least one surface thereof; disposing a second sealing assembly around the periphery of the second and third sheets of glass, thereby maintaining the second and third sheets in spaced relation to one another; and wherein the insulating glass unit further comprises the third sheet of glass and the second sealing assembly.

The present invention also provides a method of manufacturing a refrigeration door component having an outer side surface, wherein the method comprises the steps of providing a first sheet of glass; providing a second glass sheet; providing a first low-e coating adjacent to a surface of the first or second glass sheet; disposing a first sealing assembly around a periphery of the first and second glass sheets to maintain the first and second sheets in a spaced apart relationship from one another; providing an anti-fog or anti-frost coating on one of the glass sheets; and wherein the first sheet of glass, the second sheet of glass, and the first sealing assembly form an insulating glass unit having an emissivity equal to or less than 0.04 that substantially prevents the formation of condensation on the outside surface of the refrigeration door component without the application of electricity to heat the door component and substantially prevents the formation of fog or frost on the surface of the component. In an alternative embodiment, the method includes providing a third sheet of glass, which may include a low-E coating adjacent at least one surface thereof; disposing a second sealing assembly around the periphery of the second and third sheets of glass, thereby maintaining the second and third sheets in spaced relation to one another; and wherein the insulating glass unit further comprises the third sheet of glass and the second sealing assembly.

The present invention also provides a substantially transparent insulated glass unit door having an exterior side surface and for use with a refrigerated compartment, wherein the refrigerated compartment is located in an exterior environment and has an interior refrigerated compartment; the insulated glazing unit door comprises a first sheet of glass; a second glass sheet; a first seal assembly disposed about a periphery of the first and second sheets of glass to maintain the first and second sheets in a spaced apart relationship from one another; a first low emissivity surface adjacent a surface of the first or second glass sheet; and an anti-fog or anti-frost coating on a surface of one of said sheets, and said first glass sheet, said second glass sheet, and said first sealing assembly provide said insulating glass unit with a specific U value, due to which the formation of condensation on the outside surface can be effectively and significantly prevented without the application of electricity to heat the outside surface of the insulating glass unit, when the interior temperature of the refrigerated compartment is substantially equal to or less than zero degrees fahrenheit; the temperature of the external environment is approximately equal to or greater than seventy degrees Fahrenheit; and the humidity of the external environment is approximately equal to or greater than sixty percent. Alternative embodiments further include a third sheet of glass; and a second sealing assembly disposed about the periphery of the second and third sheets of glass, thereby maintaining the second and third sheets in spaced relation to one another; and may include a second low-e coating adjacent a surface of the first, second, or third glass sheet.

In an alternative embodiment, the insulating glass unit has a U value that substantially prevents the formation of condensation on the outside surfaces when the interior temperature of the refrigerated compartment is approximately equal to or less than negative forty degrees fahrenheit; the temperature of the external environment is approximately equal to or greater than eighty degrees Fahrenheit; and the humidity of the external environment is approximately equal to or greater than sixty percent.

The invention also provides a refrigeration unit comprising an insulated enclosure defining a compartment, a cooling system, and a door adapted to be mounted on an opening of the compartment, the door having an exterior side surface and comprising a first sheet of glass; a second glass sheet; a first seal assembly disposed about a periphery of the first and second glass sheets to maintain the first and second sheets in a spaced apart relationship from one another; a first low-E coating adjacent to a surface of said first glass sheet or said second glass sheet, wherein said first sheet, second sheet, first sealing assembly and said first low-E coating form an insulating glass unit having a U value substantially equal to or less than 0.2BTU/hr-sq ft-F, substantially preventing the formation of condensation on the exterior side surface of said door without the application of electricity to heat said exterior side surface; an anti-fog coating on a surface of one of the glass sheets; and a frame secured around a periphery of the insulating glass unit. In an alternative embodiment, the door further comprises a third sheet of glass, and a second sealing assembly, wherein the second sealing assembly is disposed about the periphery of the second and third sheets of glass to maintain the second and third sheets in spaced relation to one another.

The present invention also provides a glass door for a refrigerated display case, the door comprising a first glass panel having an inside surface and an outside surface; a low-e coating on an inside surface of the first glass panel; a second glass panel having an inside surface and an outside surface; a low-e coating on an inside surface of the second glass panel; an intermediate glass panel positioned between the first and second glass panels; a first spacer assembly positioned between the first and middle glass panels and a second spacer assembly positioned between the middle and second glass panels, wherein the first spacer assembly and the second spacer assembly are formed from a warm-edge spacer assembly; and an anti-fog or anti-frost coating on a surface of one of said glass panels, and a frame extending around and supporting said at least one of said glass panels. In one embodiment, the first and second glass panels have the same width and height.

The foregoing has described the principles, embodiments, and modes of operation of the present invention. The present invention should not be considered limited to the particular examples described above, however, as these examples are to be regarded as illustrative rather than restrictive. It should be apparent that modifications can be made by one skilled in the art without departing from the scope of the invention.

Although the present application has been described as being applied to refrigerator or freezer doors, other applications may include vending machines, skylights, or refrigerated vehicles, automotive reflectors, special exterior mirrors, sauna, steam rooms, shower doors, ticket windows, bathroom mirrors, external cooling devices and refrigerated cabinets exposed to high humidity or rain, and any other application where an anti-frost or anti-fog coating/film is desired. In some such applications, condensation on the second or cool side of the glass is not an issue because the glass is not in a door that is periodically opened while exposing the cooler glass to the more humid environment. As a result, key factors in the construction of glass are economics (i.e., energy costs and the cost of the glass and its installation), visible light transmittance, durability, and other considerations.

While preferred embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. Thus, it should be understood that the invention may be practiced otherwise than as specifically described herein.

Claims

1. A refrigerated door having an exterior side surface and adapted to be mounted on a refrigerated compartment, the door comprising an insulating glass unit comprising:

a first glass sheet;

a second glass sheet;

a first sealing assembly disposed about a periphery of the first and second glass sheets to maintain the first and second glass sheets in a spaced apart relationship from one another;

a first low-e coating adjacent to a surface of the first glass sheet or the second glass sheet;

an anti-fog or anti-frost coating adjacent to a surface of one of the glass sheets; and

a frame secured around a perimeter of the insulating glass unit; wherein, prior to applying the anti-fog or anti-frost coating, the surface on which the anti-fog or anti-frost coating is formed is treated with a first silane, and the anti-fog or anti-frost coating includes a second silane that is different from the first silane, and the door has a thermal conductivity U value equal to or less than 0.2BTU/hr-sq ft-F or an emissivity equal to or less than 0.04.

2. A refrigeration door as recited in claim 1 wherein said first silane comprises an aminoalkyl silicone.

3. A refrigeration door as recited in claim 1 wherein said second silane comprises 3-epoxypropyloxypropyltrimethoxysilane.

4. A refrigerated door according to claim 1 characterized in that the anti-fog or anti-frost coating is coated as a film.

5. A refrigeration door as claimed in claim 1, wherein the anti-fog or anti-frost coating is applied as a liquid.

6. A refrigeration door as claimed in claim 1, wherein said anti-fog or anti-frost coating is sparingly soluble in water.

7. A refrigeration door as recited in claim 1 wherein said anti-fog or anti-frost coating further comprises a mixture of:

i) a first component comprising 46% diacetone alcohol, 4% N-methylpyrrolidone, 4% t-butanol, 8% Cyclohexane, 6%2, 4-pentanedione, and 2% Aromatic 150; and

ii) a second component comprising 66% polyisocyanate, 1% free monomeric isocyanate, 11% xylene, 11% n-butyl acetate, and 11% toluene;

wherein the mixing ratio of the first component to the second component is 100: 40.

8. a refrigeration door as claimed in claim 7, wherein said anti-fog or anti-frost coating further comprises a solvent for diluting said mixture.

9. A refrigeration door as recited in claim 8 wherein said solvent is alcohol.

10. A refrigeration door as recited in claim 9 wherein said alcohol is diacetone alcohol or t-butanol.

11. A refrigeration door as recited in claim 1 wherein said anti-fog or anti-frost coating further comprises a mixture of:

wherein the mixing ratio of the first component to the second component is 100: 25 to 45.

12. A refrigerating door as recited in claim 11 wherein said first component and said second component are mixed in a ratio of 100: 30 to 33.

13. A refrigerating door as recited in claim 12 wherein said first component and said second component are mixed in a ratio of 100: 30.

14. a refrigeration door as recited in claim 11 wherein said second silane is present in an amount of 1% to 8%.

15. A refrigeration door as recited in claim 11 wherein said second silane is present in an amount of 6%.

16. A refrigeration door as recited in claim 1 further comprising:

a third glass sheet;

a second sealing assembly disposed about the periphery of the second and third sheets of glass so as to maintain the second and third sheets of glass in a spaced apart relationship from one another;

wherein the insulating glass unit further comprises the third sheet of glass and the second sealing assembly.

17. A refrigeration door as recited in claim 16 wherein said first seal assembly is a co-extrusion comprising a combination of a polyisobutylene sealant, a hot melt butyl sealant, a desiccant matrix, a rubber gasket, and an evaporative shield.

18. A refrigeration door as recited in claim 16 wherein said first and second seal assemblies comprise warm-edge seals.

19. A refrigeration door as recited in claim 16 further comprising a second low emissivity coating adjacent a surface of said first sheet of glass, said second sheet of glass, or said third sheet of glass.

20. A refrigeration door as recited in claim 19 wherein said first glass sheet is a glass inner sheet including a first surface and a second surface, said inner sheet first surface being disposed adjacent an interior of said refrigeration compartment; the third glass sheet is a glass outer sheet comprising a first surface and a second surface, the first surface of the outer sheet being disposed adjacent to the external environment of the refrigerated compartment; the second glass sheet is a glass middle sheet disposed between the glass inner and outer sheets; a first seal assembly disposed about the periphery of the glass inner sheet and the glass intermediate sheet to maintain the inner sheet and the intermediate sheet in a spaced apart relationship from one another; a second seal assembly disposed about the periphery of the glass middle sheet and the glass outer sheet, maintaining the middle sheet and the outer sheet in a spaced apart relationship from one another; a first low-e coating adjacent to the second surface of the inner sheet of glass; a second low-e coating adjacent to a second surface of the outer sheet of glass; the inner sheet, outer sheet, intermediate sheet, first sealing assembly, second sealing assembly, and the first and second low-E coatings form an insulating glass unit that substantially prevents condensation from forming on the first surface of the glass outer sheet without the application of electricity to heat the first surface of the glass outer sheet.

21. A refrigeration door as recited in claim 20 wherein said anti-fog or anti-frost coating is adjacent to said first surface of said glass inner sheet.

22. A refrigeration door according to claim 20, wherein said first and second seal assemblies each have a heat transfer rate equal to or less than 1.73 Btu/hr-ft-F.

23. A refrigeration door as recited in claim 20 further comprising:

a first chamber defined by the glass inner sheet, the glass intermediate sheet, and the first seal assembly;

a second chamber defined by the glass middle sheet, the glass outer sheet, and the second seal assembly; and

a gas disposed in each of the first and second chambers.

24. A refrigeration door as recited in claim 23 wherein said glass inner sheet, said glass middle sheet and said glass outer sheet have a thickness equal to one-eighth of an inch;

the glass inner sheet and the glass middle sheet are spaced apart from each other by a distance equal to one-half inch; and is

The glass middle sheet and the glass outer sheet are spaced apart from each other by a distance equal to one-half inch.

25. A refrigeration door according to claim 23, wherein said first and second seal assemblies each have a heat transfer rate equal to or less than 1.73 Btu/hr-ft-F.

26. A refrigeration door as recited in claim 25 wherein the thickness of said inner sheet of glass, said middle sheet of glass and said outer sheet of glass is equal to one-eighth of an inch;

27. A refrigeration door as recited in claim 23 wherein the gas in said first compartment is the same as the gas in said second compartment.

28. A refrigeration door as recited in claim 23 wherein the gas in said first compartment is different than the gas in said second compartment.

29. A refrigeration door as recited in claim 23 wherein said first and second low-e coatings are selected from the group consisting of titania-based silver and fluorine-doped tin oxide.

30. A refrigeration door as recited in claim 23 wherein said first low-e coating and said second low-e coating are applied by a process selected from the group consisting of sputter coating, thermal decomposition coating, and spray coating.

31. A refrigeration door as recited in claim 23 wherein said frame is formed of extruded plastic, aluminum and fiberglass.

32. The refrigeration door of claim 1 wherein the U value of the thermal conductivity of the insulating glass unit is set to be effective to substantially prevent the formation of condensation on the outside surface of the door without the application of electricity to heat the outside surface when the interior temperature of the refrigeration compartment is equal to or less than zero degrees fahrenheit; the temperature of the external environment is equal to or greater than seventy-two degrees Fahrenheit; and the humidity of the external environment is equal to or greater than sixty percent.

33. A refrigeration door as recited in claim 32 further comprising:

a first chamber defined by the first glass sheet, the second glass sheet, and the first seal assembly; and

a gas disposed within the first chamber.

34. A refrigeration door according to claim 33, wherein said first seal assembly has a heat transfer rate equal to or less than 1.73 Btu/hr-ft-F.

35. A refrigeration door as recited in claim 33 wherein said gas is selected from the group consisting of: argon, krypton and air.

36. The refrigeration door of claim 1 wherein the interior temperature of the refrigerated compartment is equal to or less than minus twenty degrees fahrenheit; the temperature of the external environment is equal to or greater than seventy degrees Fahrenheit; and the humidity of the external environment is equal to or greater than sixty percent; and the outside surface of the door is not substantially condensed.

37. The refrigeration door of claim 1 wherein the interior temperature of the refrigerated compartment is equal to or less than negative forty degrees fahrenheit; the temperature of the external environment is equal to or greater than eighty degrees Fahrenheit; and the humidity of the external environment is equal to or greater than sixty percent; and the outside surface of the door is not substantially condensed.

38. A refrigeration door as recited in claim 1 wherein said first seal assembly is a co-extrusion comprising a combination of a polyisobutylene sealant, a hot melt butyl sealant, a desiccant matrix, a rubber gasket, and an evaporative shield.

39. A refrigeration door as recited in claim 1 wherein said first seal assembly comprises a warm edge seal.

40. A method of manufacturing a refrigerated door component having an outer side surface, the method comprising the steps of:

providing a first glass sheet;

providing a second glass sheet;

providing a first low-e coating adjacent to the first or second glass sheet;

disposing a first sealing assembly around a periphery of the first and second glass sheets to maintain the first and second glass sheets in a spaced apart relationship from one another;

providing an anti-fog or anti-frost coating adjacent to a surface of one of the glass sheets,

prior to applying the anti-fog or anti-frost coating, the surface on which the anti-fog or anti-frost coating is formed is treated with a first silane, and the anti-fog or anti-frost coating includes a second silane that is different from the first silane, the first glass sheet, the second glass sheet, and the first sealing assembly form an insulating glass unit that substantially prevents condensation formation on the outside surface of the refrigeration door component without application of electricity to heat the door component, and the refrigeration door component has a thermal conductivity U-value equal to or less than 0.2BTU/hr-sq ft-F or an emissivity equal to or less than 0.04.

41. The method of claim 40, wherein the first glass sheet, the second glass sheet, and the first seal assembly define a first chamber; and further comprising the step of providing a gas within the first chamber.

42. The method of claim 40, further comprising the steps of:

providing a third glass sheet;

disposing a second sealing assembly around the periphery of the second and third sheets of glass, thereby maintaining the second and third sheets of glass in isolation from each other; and is

The insulating glazing unit further comprises the third sheet of glass and the second sealing assembly.

43. The method as recited in claim 42 wherein the third sheet of glass includes a low emissivity coating adjacent a surface thereof.

44. The method of claim 42, wherein said first seal assembly has a heat transfer rate equal to or less than 1.73 Btu/hr-ft-F.

45. The method of claim 42, wherein the second sealing component is a co-extrusion comprising a combination of a polyisobutylene sealant, a hot melt butyl sealant, a desiccant matrix, a rubber gasket, and an evaporative shield.

46. The method of claim 42, wherein the first seal assembly and the second seal assembly comprise warm-edge seals.

47. The method of claim 40, wherein said first seal assembly has a heat transfer rate equal to or less than 1.73 Btu/hr-ft-F.

48. The method of claim 47, wherein the thickness of the first glass sheet and the second glass sheet is equal to one-eighth of an inch; and is

The first glass sheet and the second glass sheet are spaced apart from each other by a distance equal to one-half inch.

49. The method of claim 47, further comprising the step of positioning the insulating glass unit in a door frame.

50. The method of claim 40, further comprising the step of positioning the insulating glass unit in a door frame.

51. The method of claim 41, wherein the gas is selected from the group consisting of: argon, krypton and air.

52. The method of claim 40, wherein the low-e coating is selected from the group consisting of titanium oxide-based silver and fluorine-doped tin oxide.

53. The method of claim 40, wherein the low-e coating is applied using a process selected from the group consisting of sputter coating, thermal decomposition coating, and spray coating.

54. The method of claim 40, wherein the first sealing assembly is a co-extrusion comprising a combination of a polyisobutylene sealant, a hot melt butyl sealant, a desiccant matrix, a rubber gasket, and an evaporative shield.

55. The method of claim 40, wherein the first seal assembly comprises a warm-edge seal.

56. A substantially transparent insulated glass unit door having an exterior side surface and adapted for use with a refrigerated compartment located in an exterior environment and having an interior refrigerated compartment; the insulated glass unit door includes:

a first glass sheet;

a second glass sheet;

an anti-fog or anti-frost coating adjacent to a surface of one of the first and second glass sheets;

wherein, prior to applying the anti-fog or anti-frost coating, the surface on which the anti-fog or anti-frost coating is formed is treated with a first silane, and the anti-fog or anti-frost coating comprises a second silane, the second silane being different from the first silane, and the door has a thermal conductivity U value equal to or less than 0.2BTU/hr-sq ft-F or an emissivity equal to or less than 0.04, the first glass sheet, the second glass sheet, and the first sealing assembly form an insulating glass unit, having an emissivity with a thermal conductivity U value equal to or less than 0.2BTU/hr-sq ft-F or equal to or less than 0.04, substantially preventing condensation formation on the outside surface of the insulating glass unit door, without applying electricity to heat the outside surface of the insulated glass unit door when the interior temperature of the refrigerated compartment is equal to or less than zero degrees Fahrenheit; the temperature of the external environment is equal to or greater than seventy degrees Fahrenheit; and the humidity of the external environment is equal to or greater than sixty percent.

57. The door of claim 56, further comprising:

a third glass sheet;

a second sealing assembly disposed about a periphery of the second and third sheets of glass to maintain the first and second sheets of glass in a spaced apart relationship from one another.

58. The door of claim 57, further comprising a second low-E coating adjacent to a surface of the first, second, or third sheet of glass.

59. The door of claim 58, wherein the insulating glass unit has a thermal conductivity U value that substantially prevents the formation of condensation on the outside surface when the interior temperature of the refrigerated compartment is equal to or less than negative forty degrees Fahrenheit; the temperature of the external environment is equal to or greater than eighty degrees Fahrenheit; and the humidity of the external environment is equal to or greater than sixty percent.

60. The door of claim 57, wherein the first and second seal assemblies each have a heat transfer rate equal to or less than 1.73 Btu/hr-ft-F.

61. The door of claim 57 wherein the second seal assembly is a co-extrusion comprising a combination of a polyisobutylene sealant, a hot melt butyl sealant, a desiccant matrix, a rubber gasket, and an evaporative shield.

62. The door of claim 57, wherein the first seal assembly and the second seal assembly comprise warm-edge seals.

63. The door of claim 56, wherein the interior temperature of the refrigerated compartment is equal to or less than minus twenty degrees Fahrenheit; the temperature of the external environment is equal to or greater than seventy degrees Fahrenheit; and the humidity of the external environment is equal to or greater than sixty percent.

64. The door of claim 56, wherein the interior temperature of the refrigerated compartment is equal to or less than negative forty degrees Fahrenheit; the temperature of the external environment is equal to or greater than eighty degrees Fahrenheit; and the humidity of the external environment is equal to or greater than sixty percent.

65. The door of claim 56, wherein the first seal assembly is a co-extrusion comprising a combination of a polyisobutylene sealant, a hot melt butyl sealant, a desiccant matrix, a rubber gasket, and an evaporative shield.

66. The door of claim 56, wherein the first seal assembly comprises a warm-edge seal.

67. A refrigeration unit comprising an enclosure defining a compartment, a cooling system, and a door adapted to be mounted on an opening of the compartment, the door having an exterior surface and comprising:

a first glass sheet;

a second glass sheet;

the first glass sheet, the second glass sheet, the first seal assembly, and the first low-E coating form an insulating glass unit that substantially prevents condensation from forming on the exterior side surface of the door without the application of electricity to heat the exterior side surface;

an anti-fog or anti-frost coating adjacent to a surface of one of the glass sheets and, prior to application of the anti-fog or anti-frost coating, the surface on which the anti-fog or anti-frost coating is formed is treated with a first silane and the anti-fog or anti-frost coating comprises a second silane, the second silane being different from the first silane;

a frame secured around a perimeter of the insulating glass unit; and the door has a thermal conductivity U value equal to or less than 0.2BTU/hr-sq ft-F or an emissivity equal to or less than 0.04.

68. The refrigeration unit of claim 67, further comprising:

a third glass sheet; and

a second sealing assembly disposed about a periphery of the second and third sheets of glass to maintain the second and third sheets of glass in a spaced apart relationship from one another.

69. The refrigeration unit of claim 68, wherein said first seal assembly and said second seal assembly each have a heat transfer rate equal to or less than 1.73 Btu/hr-ft-F.

70. A refrigeration unit as recited in claim 68 wherein the second seal assembly is a co-extrusion comprising a combination of a polyisobutylene sealant, a hot melt butyl sealant, a desiccant matrix, a rubber gasket, and an evaporative shield.

71. The refrigeration unit of claim 68, wherein the first seal assembly and the second seal assembly comprise warm-edge seals.

72. The refrigeration unit of claim 68, further comprising:

a first chamber defined by the first glass sheet, the second glass sheet, and the first seal assembly;

a second chamber defined by the second glass sheet, the third glass sheet, and the second sealing assembly; and

a gas disposed within each of the first and second chambers.

73. The refrigeration unit of claim 67, wherein said first seal assembly has a heat transfer rate equal to or less than 1.73 Btu/hr-ft-F.

74. A refrigeration unit as recited in claim 67 wherein the first seal assembly is a co-extrusion comprising a combination of a polyisobutylene sealant, a hot melt butyl sealant, a desiccant matrix, a rubber gasket, and an evaporative shield.

75. The refrigeration unit of claim 67, wherein the first seal assembly comprises a warm-edge seal.