WO2008085288A1

WO2008085288A1 - Method of shaping insulation

Info

Publication number: WO2008085288A1
Application number: PCT/US2007/025606
Authority: WO
Inventors: Michael D. Grah
Original assignee: Sealed Air Corporation (Us)
Priority date: 2007-01-11
Filing date: 2007-12-14
Publication date: 2008-07-17

Abstract

An article, such as an article (22) comprising an insulation material, may be shaped by the following steps. A first film (12) is attached to a second film (14) to provide an interior space between the first and second films. The first and second films have different shrink characteristics so that at a selected temperature and direction the shrink tension of the first film (12) is greater than the shrink tension of the second film (14). The article (22) is positioned in the interior space. The first film (12) is heated to the selected temperature to activate the shrink characteristic of the first film and shorten the first film in the selected direction relative to the second film (14) and reshape the article between the first and second films. The reshaped article may be used to insulate an object, such as a pipe.

Description

METHOD OF SHAPING INSULATION

This application claims priority from and the benefit of U.S. Provisional Patent Application Serial No. 60/879,874 filed January 1 1, 2007, which is incorporated in it s entirety by reference.

BACKGROUND

The present invention relates to insulation products, and more particularly to insulation products that may be reshaped.

SUMMARY

An article, such as an article comprising an insulation material, may be shaped by the following steps. A first film is attached to a second film to provide an interior space between the first and second films. The first and second films have different shrink characteristics so that at a selected temperature and direction the shrink tension of the first film is greater than the shrink tension of the second film. The article is positioned in the interior space. The first film is heated to the selected temperature to activate the shrink characteristic of the first film and shorten the first film in the selected direction relative to the second film and reshape the article between the first and second films.

An insulation product comprises a first film attached to a second film to provide an interior space between the first and second films. The first and second films have different shrink characteristics so that at a selected temperature and direction the shrink tension of the first film is greater than the shrink tension of the second film. An insulation material is within the interior space. The insulation material may comprise one or more of any of the following: aerogel, foam plastic insulation, fiberglass insulation, and cellulosic insulation. The insulation product may be used to insulate an object, such as a pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the insulation product before the shrink attribute is activated; FIG. 2 is a side elevation view of the insulation product of Figure 1 ;

FIG. 3 is a representative sectional view taken along lines III-III of Figure 1 ; FIG. 4 is a representative sectional view taken along lines IV-IV of Figure 1; and FIG. 5 is a perspective view of the insulation product of Figure 1 after the shrink attribute was activated;

FIG. 6 is a representative sectional view taken along lines VI-VI of Figure 5; and FIG. 7 is a perspective view of the insulation product having a helical configuration after the shrink attribute was activated.

DETAILED DESCRIPTION

In an embodiment of the invention, an article 22, such as an insulation material, may be shaped by the following steps. A first film 12 is attached to a second film 14 to form an interior space 20. The article 22 is positioned in the interior space 20. The first film 12 is heated to activate the shrink characteristic of the first film in order to shorten the first film relative to the second film and reshape the article between the first and second films.

Films The first and second films 12, 14 may each independently comprise one layer, or multiple layers, for example, at least and/or at most any of 2, 3, 4, 5, 7, 9, and 11 layers. As used herein in reference to a film, the term "layer" refers to a discrete film component which is substantially coextensive with the film and has a substantially uniform composition. Where two or more directly adjacent layers have essentially the same composition, then these two or more adjacent layers may be considered a single layer for the purposes of this application.

The first and seconds films may each independently comprise one or more thermoplastic polymers, for example, one or more of polyolefins (e.g., polyethylenes, polypropylenes, ethylene/alpha-olefin copolymers), ethylene/vinyl alcohol copolymers, ionomers, vinyl plastics (e.g., polyvinyl chloride, polyvinylidene chloride), polyamide, thermoplastic polyurethane, and polyester.

The first and second films may each independently comprise any one or more of the polymers (or types of polymers) discussed herein in at least about, and/or at most about, any of the following weight percent values: 30, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97, 99 and 100% by weight of the film or by weight of the layer.

The first and second films may each independently have an average total thickness of at least about, and/or at most about, any of the following: 0.5, 1, 2, 3, 4, 5, 7, 9, 10, and 15 mils. Any of the layers of the first and second films may each independently have a thickness of at least about, and/or at most about, any of the following: 0.05, 0.1, 0.5, 1, 1.3, 1.5, 2, and 2.5 mils. Any of the layers, such as a barrier layer, described herein may have a thickness as a percentage of the total thickness of the film of at least about, and/or at most about, any of the following: 1, 3, 5, 7, 10, 15, 20, 25, 30, 35, 40, 45, and 50 percent. The second film may comprise non-woven material, for example, such as the non-woven materials available from DuPont under the TYVEK and TYPAR trade names, so that the second film may resist the transmission of liquid water but be permeable for the transmission of water vapor.

Barrier Polymer

The first and second films may each independently comprise one or more barrier polymers. A "barrier polymer" is a polymer that markedly decreases the transmission rate of oxygen through a film incorporating the polymer, relative to a comparable film not incorporating the polymer. This may be advantageous, for example, if the films 12, 14 are attached using a vacuum sealing method, as discuss herein, so that the barrier polymer may enhance the ability of the film to maintain a less than atmospheric pressure within the interior space 20.

If the film is multilayered, then the one or more layers of the film that incorporate one or more barrier polymers in an amount sufficient to notably decrease the transmission rate of oxygen through the film may be considered "barrier layers." If the film is monolayer and incorporates one or more barrier polymers, then the monolayer film itself may be considered a "barrier layer."

The first and second films, and/or a barrier layer of these films, may each independently comprise one or more of any of the barrier polymers described herein in an amount of at least about, and/or at most about, any of the following: 10%, 20%, 30%, 40%,

50%, 60%, 70%, 80%, 90%, 95%, 97%, 98%, 99%, and 99.5%, based on the weight of the film or the barrier layer, respectively.

Exemplary barrier polymers include: ethylene/vinyl alcohol copolymer ("EVOH"), polyvinyl alcohol ("PVOH"), polyvinylidene chloride ("PVdC"), polyalkylene carbonate, polyester (e.g., PET, PEN), polyacrylonitrile ("PAN"), and polyamide.

Useful EVOH may have an ethylene content of at least about, and/or at most about, any of the following: 20, 25, 32, 35, 40, 42, 45, and 48 wt. %. EVOH may include saponified or hydrolyzed ethylene/vinyl acetate copolymers, such as those having a degree of hydrolysis of at least 50%, preferably of at least 85%.

Oxygen Transmission Rate The first and second films 12, 14 may each independently have an oxygen transmission rate of at least, and/or at most, any of the following values: 1, 2, 5, 10, 100, 500, and 1,000 cubic centimeters (at standard temperature and pressure) per 100 square inches per day per 1 atmosphere of oxygen pressure differential measured at 0% relative humidity and 23°C. Unless otherwise noted, all references to oxygen transmission rate ("OTR") in this Application are reported in these units measured at these conditions according to ASTM D- 3985; and the OTR of a film is in reference to, and measured for, the film in an unperforated state. The film may have any of the above listed OTRs in conjunction with any of the film average thicknesses listed herein. For example, the film may have an average thickness of at least about 1.5 and at most about 3 mils, and an OTR of at least about 10 and at most about 500 cc/100in²/day; also by way of example, the film may have an average thickness of at least about 0.5 and at most about 15 mils, and an OTR of at least about 1 and at most about 1,000 cc/100in²/day.

Shrink Characteristics The first and second films are manufactured to have different shrink characteristics.

"Shrink characteristics" of a film refers to the behavior of the film as characterized by the free shrink and/or shrink tension tests discussed herein. For example, in an embodiment of the invention, the shrink tension of the first film is greater than the shrink tension of the second film, at a selected temperature and direction. Accordingly, in an embodiment of the invention, the second film may be made without a solid-state orientation step, for example, by making the second film using the hot blown tubular film process without a subsequent solid-state orientation step. The term "solid- state orientation" describes an orientation process carried out at a temperature higher than the highest glass transition temperature (Tg) of the polymers making up the structure and lower than the highest melting point (Tm) of at least one polymer - that is, at a temperature where the polymers, or at least some of the polymers, are not in the molten state. "Solid-state orientation" is contrasted to "melt-state orientation," which is a process, such as the hot blown tubular film process, where stretching takes place upon emergence of the molten resins from the die. As used herein, if the terms "orientation" and "oriented" are not further qualified, then these terms mean "solid-state orientation" and "solid-state oriented," respectively, so that a film that is "non-oriented" means that the film has not undergone solid- state orientation. The second film may be non-oriented. The first film 12, and optionally the second film 14, may be solid-state oriented (i.e., oriented), for example, by quenching a relatively thick tube, which is then reheated to the so- called orientation temperature (i.e., above the Tg and below the Tm as discussed above), and then biaxially stretched at this temperature by a tubular solid-state orientation process using a trapped bubble. Solid state orientation may also be carried out, for example, by use of a tentering frame or by use of a series of heated and speed controlled rollers, as is known in the art.

These films may each independently be either melt-state oriented or solid-state oriented (if at all) in any direction by at least about, and/or at most about, any of the following ratios: 1.5: 1, 2: 1, 2.5: 1, 2.8: 1; 2.9: 1, 3: 1, 3.5: 1 , 4: 1, 5: 1, 6: 1, 7: 1, 8: 1, 9: 1, 10: 1; 12: 1; and 15: 1. Each film may independently be stretched by any of these amounts in one direction and another of any of these amounts in another direction.

Free Shrink The first film 12 may have a free shrink at 185°F (85°C) in at least one direction (e.g., the machine direction or the transverse direction) and/or in both the machine and transverse directions of at least about, and/or at most about, any of the following: 5%, 7%, 9%, 10%, 12%, 15%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 70%, 80%, and 90%. The first film may have any of the forgoing shrink amounts in the machine and/or transverse directions at any of the following temperatures: 130°F, 160⁰F, 180°F, 200⁰F, 210⁰F, 215°F, 230⁰F, 260⁰F, and 300⁰F. For example, the film may have a free shrink at 180⁰F in the transverse direction of at least about 60% and a free shrink at 160⁰F in the machine direction of at most about 10%. Also, the film may have any combination of the forgoing shrink values at differing temperatures; for example, the film may have a free shrink at 180⁰F in at least one direction of at least about 70% and a free shrink at 160⁰F in any direction of at most about 5%. The film may be annealed, for example, to decrease the shrink attribute at a selected temperature (e.g., 150⁰F).

The free shrink of a film is determined by measuring the percent dimensional change in a 10 cm x 10 cm film specimen when subjected to selected heat (i.e., at a specified temperature exposure) according to ASTM D2732, which is incorporated herein in its entirety by reference. All references to free shrink in this application are measured according to this standard.

The second film may have a free shrink at 185°F (85°C) in at least one direction (e.g., the machine direction or the transverse direction) and/or in both the machine and transverse directions of at most about, and/or at least about, any of the following: 2%, 3%, 4%, 5%, 7%, and 10%. The first and/or second films may each independently be annealed or heat-set to slightly or substantially reduce the free shrink of an oriented film.

Shrink Tension As is known in the art, a heat-shrinkable film shrinks upon the application of heat while the film is in an unrestrained state. If a shrink film is restrained from shrinking to some extent — for example by an article around which the film shrinks — then the tension of the heat-shrinkable film increases upon the application of heat. Accordingly, a heat-shrinkable film that has been exposed to heat so that at least a portion of the film is either reduced in size (unrestrained) or under increased tension (restrained) is considered to have had its shrink characteristic activated, for example, to become a heat-shrunk (i.e., heat-contracted) film.

The first film 12 may have a shrink tension at 185°F in at least one direction, and/or in at least both of the machine and transverse directions, of at least about, and/or at most about, any of the following: 50 psi, 75 psi, 100 psi, 125 psi, 150 psi, 175 psi, 200 psi, 225 psi, 250 psi, 275 psi, 300 psi, 325 psi, 350 psi, 400 psi, 450 psi, 500 psi, 550 psi, and 600 psi. Further, the first film may have any of the preceding shrink tensions measured at a temperature selected from any of 130°F, 160°F, 180°F, 200°F, 21O⁰F, 215°F, 230⁰F, 26O⁰F, and 300⁰F. The first film may have unequal shrink tension in both directions, that is differing shrink tension in the machine and transverse directions. The first film may not have a shrink tension in one direction. Shrink tension is measured at a specified temperature (e.g., 185⁰F) in accordance with ASTM D 2838 (Procedure A), which is incorporated herein in its entirety by reference. All references to shrink tension in this application are by this standard.

The second film 14 may have a shrink tension at 185°F in at least one direction, and/or in at least both of the machine and transverse directions, of at least about, and/or at most about, any of the following: 25 psi, 50 psi, 75 psi, 100 psi, 125 psi, 150 psi, 175 psi, and 200 psi. Further, the second film may have any of the preceding shrink tensions measured at a temperature selected from any of 130⁰F, 160⁰F, 180⁰F, 200⁰F, 210⁰F, 215°F, 23O°F, 260⁰F, and 300⁰F. The second film may not have a shrink tension in one or both directions.

The shrink tension of the first film may be greater than the shrink tension of the second film, at a selected temperature of 185°F and in the same direction, by at least about any of the following amounts: 50 psi, 75 psi, 100 psi, 125 psi, 150 psi, 175 psi, 200 psi, 225 psi, 250 psi, 275 psi, 300 psi, 325 psi, 350 psi, 400 psi, 450 psi, 500 psi, 550 psi, and 600 psi. Further, the first and second films may have any of the preceding shrink tension differences measured at a temperature selected from any of 130⁰F, 160⁰F, 180⁰F, 200⁰F, 210⁰F, 215°F, 230⁰F, 260⁰F, and 300⁰F.

Drawability of the Second Film

The second film may have a sufficiently low yield strength at the temperature selected for the activation of the shrink characteristic of the first film so that the second film does not unduly resist the tension applied by the first film upon activation of the shrink characteristic, as discussed herein. Accordingly, the second film may be capable of substantial plastic deformation, or drawability, so that the stress required at the yield point of the second film (i.e., the yield stress) and the stress required for plastic deformation of the second film are less than the shrink tension produced by the first film.

The yield strength of the second film may also be sufficiently high at room temperature to withstand, without excessive plastic deformation, the expected handling and use conditions, such as the handling conditions during machine processing of the second film to create the enclosure.

Making the Films The first and second films 12, 14 may each independently be made by thermoplastic film-forming processes known in the art. The films may be made by extrusion or coextrusion utilizing, for example, a blown tubular (trapped bubble) film process or a flat film (i.e., cast film or slit die) process. The films may also be made by applying one or more layers by extrusion coating, adhesive lamination, extrusion lamination, solvent-borne coating, or by latex coating (e.g., spread out and dried on a substrate). A combination of these processes may also be employed. These processes are known to those of skill in the art; see, for example, U.S. Patent Application Publication 2006/0286321 Al published December 21, 2006 to Broadus et al.

Attaching the First Film to the Second Film The first film 12 may be attached to the second film 14 to provide an interior space 20 between the first and second films. The films may be attached, for example, by heat sealing the films, by applying adhesives to adhere the films together, and/or by mechanically coupling the films together, for example, using staples. Suitable attachment methods (e.g., heat sealing, adhesive attachment systems, mechanical attachment systems) are known to those of skill in the art.

The first and second films 12, 14 may be attached along the left and right perimeters to form left and right side seals 16. The first and second films 12, 14 may also be attached along the front and rear perimeters to form end seals 18. At least one of the side or end seals may not be formed until after the article 22 has been positioned between the first and second films and within the interior space 20. This would allow an access opening to the interior space 20.

The pressure within the interior space 20 may be essentially the same as the pressure outside of the interior space (i.e., immediately outside of enclosure 24). The equalization of pressure may be accomplished, for example, by providing one or more vent holes or perforations in the first and/or second films (not illustrated), or by mechanical attaching the first and second films, or by not attaching one or more of the side perimeters or the end perimeters of the first and second films so that the enclosure 24 remains "open."

The pressure within the interior space 20 may be less than the pressure outside of the interior space. For example, the first and second films may be attached to each other using vacuum sealing to enclose the article 22 within the interior space 20 so that the interior space has a pressure less than the pressure outside of the interior space, for example, less by at least about, and/or at most about, any of the following: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, and 14.5 pounds/square inch. The absolute pressure within the interior space may be at least about, and/or at most about, any of the following: 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, and 14.5 pounds/square inch absolute. Vacuum sealing methods are known to those of skill in the art. The maintenance of below-atmospheric pressure within the interior space 20 may be facilitated if the first and second films 12, 14 comprise barrier polymers as discussed herein.

Article Comprising Insulation Material

An article 22, such as an insulation material, may be positioned in the interior space 20 between the first and second films 12, 14. The article 22 may be positioned in the interior space 20 between the first and second films before these films are attached to each other, or may be positioned in the interior space 20 between the first and second films after some portions of the film perimeters have been attached to each other. If vacuum sealing is used, as discussed above, then the article 22 may be enclosed within the interior space 20, for example, by the perimeter side and end seals 16, 18, in order to maintain a low pressure within interior space 20. The article 22 may comprise an insulation material. Insulation products 26, 28 comprise article 22 that comprises an insulation material. The insulation material may comprise one or more of: aerogel insulation, fiberglass insulation, foam plastic insulation, and cellulosic insulation. The article may comprise any one or more of the insulation materials discussed herein an amount of at least about, and/or at most about, 50, 70, 90, and 95 weight %. The article may consist essentially of any of these insulation materials, or may consist of any of these insulation materials.

The article 22 when positioned within the interior space 20 may have the configuration, for example, of a sheet, blanket, or rectangular-sided plank that lies flat before the shrink characteristics of the first film are activated, as described herein. The article may have an average thickness of at least about, and/or at most about, any of the following: 5, 25, 50, 75, 100, 150, 200, and 300 mils; and further at least about, and/or at most about, any of the following: 0.5, 1, 3, 5, 7, 10, 15, and 20 inches.

Where the article 22, for example, the article comprising insulation material, has relatively low compressibility, then a greater amount of vacuum (i.e., a lower pressure), if any, may be established in the interior space 20 without compressing the article by an undesired amount. Accordingly, articles having a low compressibility characteristic may be particularly advantageous if vacuum sealing is used to enclose the article in the interior space. It is useful for the article to have a configuration, composition, and characteristic such that it bends in response to the force applied by the first film as the film's shrink characteristic is activated, as discussed herein. The article preferably exhibits a flexural modulus sufficient to withstand the expected handling and use conditions. The flexural modulus of the article may be at most about any of the following values: 4,000; 3,000; 2,500; 2,000; 1,900; 1,800; 1,700; 1,500; 1,200; 1,100; 1,000; 900; 800; 700; 600; and 500 psi. The flexural modulus of the article may be at least about any of the following values: 800; 900; 1,000; 1,100; 1,200; 1,700; 1,800; 1,900; 2,000; 2,200; 2,500; and 3,000 psi (pounds/square inch). The flexural modulus (i.e., the tangent modulus of elasticity in bending) may be measured in accordance with ASTM D790-00 (Procedure A or B, depending on the nature of the article, as set forth in the ASTM test), which is incorporated herein in its entirety by reference. If the article is so flexible that it is difficult to run the above ASTM test procedure to calculate the flexural modulus (e.g., a foam with a flexural modulus of less than about 1,000 psi), then the ASTM test may be modified by using a higher "Z" (i.e., rate of straining) and/or stacking several samples of the article together (taping the sample ends together) to run the test.

Aerogel Insulation Material The insulation material may comprise aerogel. The aerogel may be in the form of an aerogel composite. Aerogel is a light weight solid material comprising, for example, inorganic material (e.g., silica) and/or organic materials (e.g., urethane). Aerogel may have a porosity, for example, of about 95%. Aerogels may have extremely small pores, which enhance the aerogel's thermal insulation characteristics. Aerogel composite refers to material comprising aerogel and at least one substance that imparts flexibility and/or reinforcement attributes to the composite, as is known in the art.

Aerogels, aerogel composites, aerogel insulation materials, and substances useful to impart flexibility and reinforcement for aerogel composites are described in U.S. Patent Application Publication 2006/0240216 Al published October 26, 2006 by Stepanian et al and assigned to Aspen Aerogels, Inc., which is incorporated herein in its entirety by reference.

The insulation material may comprise aerogel in an amount of at least about, and/or at most about, any of the following: 50, 60, 70, 80, 90, and 95 wt.%, based on the weight of the insulation material. The insulation material may comprise aerogel composite in an amount of at least about, and/or at most about, any of the following: 50, 60, 70, 80, 90, and 95 wt.%, based on the weight of the insulation material.

Aerogel insulation materials are available, for example, from Aspen Aerogels, Inc. under the CRYOGEL, SPACELOFT, and PYROGEL trade names and from Cabot Corporation under the NANOGEL trade name.

Foam Plastic Insulation Material

The insulation material may comprise foam plastic insulation, which may comprise, for example, one or more polymers, such as one or more of any of the following: polyolefin (e.g., polyethylene, polypropylene), polystyrene, polyurethane, polyisocyanurate, polyamide, polyester, polyvinyl chloride, ionomer, and elastomer. The one or more polymers may be thermoplastic (e.g., polyolefins) or may be thermoset (e.g., polyurethanes and elastomers).

The foam plastic insulation may comprise closed cell foam. The term "closed cell" foam as used herein means that the foam comprises an open cell content of 30 volume % or less, measured according to ASTM D2856-94 (Procedure A). (For foam having a thickness of less than 0.984 inches, then the foam sample size shall be 0.984 inches by 0.984 inches by the actual average thickness of the foam.) Further, the closed cell foam may comprise no more than about any of the following amounts of open cell volume %: 20%, 10%, 5%, 1%, and 0%.

Also, the cells of the closed cell foam may consist essentially of closed cells, or may consist of closed cells.

Alternatively, the foam plastic insulation may comprise open cell foam. The term "open cell" foam as used herein means that the foam comprises an open cell content of greater than 30 volume %, measured according to ASTM D2856 as set forth above. The open cell foam may include an open cell content of greater than about any of the following: 40, 50, 60, and 90 volume %. The open cell content may be 100 volume %, or less than about any of the following: 95, 90, 85, and 80 volume %.

The may have an average cell size of at least about any of the following values: 0.01, 0.05, 0.1, 0.5, and 1 mm. The foam may have an average cell size of at most about any of the following values: 10, 5, 3, 1, and 0.5 mm. The average cell size may be measured according to ASTM D3576-98 (Procedure A).

The density of the foam may be at least about any of the following: 0.5, 1, 3, 5, 8, 10, 12, 15, 20, 25, 30, and 35 pounds per cubic foot (Ib/ft3). The density of the foam may be at most about any of the following values: 40, 35, 30, 25, 20, and 15 Ib/ft3. The density may be measured according to ASTM D3575-00, Suffix W, Test Method A, which is incorporated herein in its entirety by reference.

The area density of the foam may be at least about any of the following: 5, 10, 15, 20,

25, 30, 35, 40, 45, 50, and 55 grams per square foot (gram/ft2). The area density of the foam may be at most about any of the following values: 300, 200, 100, 80, 75, 70, 65, 60, 55, 50,

45, 40, 35, 30, and 25 gram/ft2. The area density may be calculated by dividing the density of the foam by the average thickness of the foam.

Activating the Shrink Characteristic of the First Film "Activating the shrink characteristic of the film" means that the film is exposed to conditions that cause one or more of: 1) the film to shrink by at least about 10% of the length in at least one direction (for example, if the film is unrestrained) or 2) the tension in the film to increase by at least about 50 psi in at least one direction (for example, if the film or film portion is restrained). Activating the shrink characteristic of the first film may be accomplished, for example: 1) by exposing the film to hot gas or vapor, for example by exposing the film to hot air from a device such as a portable hot-air blower (e.g., hair dryer) or by conveying the film through a hot-air tunnel, 2) by immersing the film in a hot-water bath, or 3) by heating the film by exposure to infrared radiation via IR heaters. The film may be heated to the selected temperature - e.g., the temperature at which the shrink characteristic is activated — which may be, for example, at least about, and/or at most about, any of the following temperatures: 150, 160, 170, 180, 190, 200, 210, 215, and 220⁰F.

The entire insulation product 26 comprising the enclosure 24 and the article 22 may be exposed to the conditions that are used to heat the first film in order to activate the shrink characteristic of the film. For example, the entire insulation product 26 may be immersed in a hot water bath or may be conveyed through the hot air tunnel. Alternatively, the exposure conditions may be more focused, for example, by directing the hot air stream to impinge on the first film by using a hot air blower.

The results of the activation of the activation of the shrink characteristic of the first film 12 will now be described in the situation where the first film 12 has for the most part a shrink characteristic in one direction, namely, along the length "L" as identified in Figure 2. Upon heating the first film 12 to a selected temperature (i.e., a temperature above the shrink activation temperature), the first film 12 will contract to shorten in the length direction. This will cause the article 22 within the interior space between the first and second films to bend or curve toward the first film as shown in Figures 5 and 6. If the second film 14 does have some amount of shrink characteristic, this is in essence overpowered by the shrink tension resulting from the activation of the shrink characteristic of the first film 12, since at the selected temperature and direction (i.e., length), the shrink tension of the first film 12 is greater than the second film 14. As a result, the article 22, such as an aerogel insulation material, is reshaped to a curved configuration between the first and second films (Figure 6). If the pressure within the interior space 20 is less than the ambient pressure outside of the insulation product 22, then the first film 12 conforms to the concave surface of the article 22, as illustrated in Figures 5 and 6.

The results of the activation of the activation of the shrink characteristic of the first film will now be described in the situation where the first film 12 has for the most part a shrink characteristic in two directions, namely, along the length "L" as identified in Figure 2 and along the width "W" as identified in Figure 4. Upon heating the first film 12 to a selected temperature (i.e., a temperature above the shrink activation temperature), the first film 12 will contract to shorten in the length direction and width directions. This will cause the article 22 in the interior space between the first and second films to bend or curve toward the first film in a helical configuration as shown in Figure 7. Insulation product 28 (Figure 7) comprises first film 12 having a shrink characteristic in both the L and W directions.

Use of the Insulation Product

The insulation product 26, 28 may be stored and shipped in a flat configuration

(Figures 1 and 2) so that several of the insulation products may be stacked upon each other to minimize storage and handling requirements. The insulation products may be shaped at or near the point of end use by activating the shrink characteristic of the first film as discussed herein. The resulting reshaped insulation product may be used, for example, to insulate an object such as a pipe or a pipeline. The curved configuration of the reshaped insulation product facilitates its placement or installation around the pipe during installation of the insulation.

The following examples are presented for the purpose of further illustrating and explaining the present invention and are not to be taken as limiting in any regard. Unless otherwise indicated, all parts and percentages are by weight. Example 1

A first film was a three-layer film having a core layer of poly(lactic acid) and skin layers of glycol-modified poly(ethylene terephthalate) (i.e., "PETG"), which was a copolymer of terephthalic acid, ethylene glycol, and cyclohexane dimethanol ("CHDM").

The first film had a thickness of about 1.7 mils and had a uniaxial shrink characteristic; namely, believed to have a free shrink in the transverse direction of about 70% at 185°F and less than about 3% at 185F in the machine direction. The first film was cut into a sheet having 45 cm length and 15 cm width dimensions so that the higher heat shrink characteristic corresponded to the length dimension.

A second film was about 1-mil thick film. The second film was biaxially oriented and heat set polyethylene terephthalate ("PET") available from DuPont Teijin Films under the MYLAR trade name. This film had minimal if any shrink characteristic; namely, believed to have a free shrink in either direction of less than about 3% at 185°F. The second film was cut into a sheet having 45 cm length and 15 cm width dimensions. The first and second films were heat sealed together along three edges to form a 45 cm by 12 cm enclosure having an opening.

An insulation blanket of aerogel available from Aspen Aerogel, Inc. under the

SPACELOFT AR3103 trade name, having dimensions of 35 cm length by 10 cm width by 0.25 inch thick, was placed inside the enclosure. The enclosure was then sealed closed to enclose the insulation blanket inside the enclosure using a vacuum sealing process using

Model No. X200 (1994) vacuum packaging machine from Koch Equipment LLC. The machine was operated to place about a 6 Torr (0.12 psia) absolute pressure within the interior space. The vacuum-sealed enclosure enclosing the insulation blanket could be laid flat on a horizontal surface under its own weight.

The resulting insulation product was passed through a hot air tunnel having an air temperature of about 325°F to heat the films and activate the shrink characteristic of the first film, which contracted or shortened along its length. As a result, the insulation blanket was reshaped to assume a curved configuration in the length direction, while the width direction remained relatively straight. Example 2

A first film was a 7-layer shrink film available from Cryovac under the trade name B210. The first film had a core layer of PVdC (specifically, a vinyl chloride/methyl acrylate copolymer) as an oxygen barrier layer. The first film had a thickness of about 2.5 mils and had a biaxial shrink characteristic; namely, believed to have a free shrink in the transverse direction of about 48% at 185°F and about 32% in the machine direction. The first film was cut into a sheet having 45 cm length and 15 cm width dimensions so that the higher heat shrink characteristic corresponded to the length dimension. A second film was a forming web film having a thickness of about 3 mils available from Cryovac, Inc. This film had minimal if any shrink characteristic; namely, believed to have a free shrink in either direction of less than about 3% at 185°F. The second film was cut into a sheet having 45 cm length and 15 cm width dimensions. The first and second films were heat sealed together along three edges to form a 45 cm by 12 cm enclosure having an opening.

An insulation blanket of aerogel available from Aspen Aerogel, Inc. under the SPACELOFT AR3103 trade name, having dimensions of 35 cm length by 10 cm width by 0.25 inch thick, was placed inside the enclosure. The enclosure was then sealed closed to enclose the insulation blanket inside the enclosure using a vacuum sealing process using Model No. X200 (1994) vacuum packaging machine from Koch Equipment LLC. The machine was operated to place about a 6 Torr (0.12 psia) absolute pressure within the interior space. The vacuum-sealed enclosure enclosing the insulation blanket could be laid flat on a horizontal surface under its own weight.

The resulting insulation product was passed through a hot water bath at 85°C for 5 seconds to heat the films and activate the shrink characteristic of the first film, which contracted or shortened along its length and width. The resulting insulation blanket was reshaped to assume a helical shape.

Any numerical value ranges recited herein include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if it is stated that the amount of a component or a value of a process variable (e.g., temperature, pressure, time) may range from any of 1 to 90, 20 to 80, or 30 to 70, or be any of at least 1 , 20, or 30 and/or at most 90, 80, or 70, then it is intended that values such as 15 to 85, 22 to 68, 43 to 51, and 30 to 32, as well as at least 15, at least 22, and at most 32, are expressly enumerated in this specification. For values that are less than one, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1 as appropriate. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner.

The above descriptions are those of preferred embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the claims, which are to be interpreted in accordance with the principles of patent law, including the doctrine of equivalents. Except in the claims and the specific examples, or where otherwise expressly indicated, all numerical quantities in this description indicating amounts of material, reaction conditions, use conditions, molecular weights, and/or number of carbon atoms, and the like, are to be understood as modified by the word "about" in describing the broadest scope of the invention. Any reference to an item in the disclosure or to an element in the claim in the singular using the articles "a," "an," "the," or "said" is not to be construed as limiting the item or element to the singular unless expressly so stated. The definitions and disclosures set forth in the present Application control over any inconsistent definitions and disclosures that may exist in an incorporated reference. All references to ASTM tests are to the most recent, currently approved, and published version of the ASTM test identified, as of the priority filing date of this application. Each such published ASTM test method is incorporated herein in its entirety by this reference.

Claims

CLAIMSWhat is claimed is:

1. A method of shaping an article comprising: attaching a first film to a second film to provide an interior space between the first and second films, wherein the first and second films have different shrink characteristics so that at a selected temperature and direction the shrink tension of the first film is greater than the shrink tension of the second film; positioning the article in the interior space; and heating the first film to the selected temperature to activate the shrink characteristic of the first film and shorten the first film in the selected direction relative to the second film and reshape the article between the first and second films.

2. The method of claim 1 wherein the attaching step comprises sealing the first and second films to each other to enclose the article within the interior space.

3. The method of claim 1 wherein: the attaching step comprises vacuum sealing the first and second films to each other to enclose the article within the interior space; and the interior space has a pressure less than the pressure outside of the interior space.

4. The method of claim 1 wherein the pressure within the interior space is essentially the same as the pressure outside of the interior space.

5. The method of claim 1 where at least one of the first and second films has at least one perforation to allow fluid communication between the interior space between the first and second films and the exterior space outside of the first and second films.

6. The method of any preceding claim wherein the first film has a shrink tension in the machine direction at 185⁰F of at least about 100 psi.

7. The method of any preceding claim wherein the first film has a shrink tension in the machine direction at 185 °F of at least about 100 psi and a shrink tension in the transverse direction at 185°F of at least about 100 psi.

8. The method of any preceding claim wherein the first film has a free shrink in the machine direction at 185°F of at least about 25%.

9. The method of any preceding claim wherein the first film has a shrink tension in the machine direction at 185 °F of at least about 25% and a shrink tension in the transverse direction at 185°F of at least about 25%.

10. The method of any of claims 1-6 wherein the first film has a shrink tension in the machine direction at 185 °F of at least about 100 psi and a shrink tension in the transverse direction at 185⁰F of at most about 50 psi.

1 1. The method of any preceding claim wherein the second film has a shrink tension at 185°F in both the machine and transverse directions of at most about 75 psi.

12. The method of any preceding claim wherein the first film comprises thermoplastic polymer.

13. The method of any preceding claim wherein the second film comprises thermoplastic polymer.

14. The method of any preceding claim wherein the first and second films comprise one or more barrier polymers.

15. The method of any of claims 1-3 and 6-14 wherein the first and second films have an oxygen transmission rate of less than about 100 cubic centimeters (at standard temperature and pressure) per 100 square inches per day per 1 atmosphere of oxygen pressure differential measured at 0% relative humidity and 23°C.

16. The method of any preceding claims wherein the article comprises aerogel.

17. The method of any of claims 1-15 wherein the article comprises foam.

18. The method of any of claims 1-15 wherein the article comprises a closed-cell foam.

19. The method of any of claims 1-15 wherein the article comprises an open-cell foam.

20. The method of any of claims 1-15 wherein the article comprises fiberglass.

21. The method of any of claims 1-15 wherein the article comprises cellulosic material.

22. An insulation product comprising: a first film attached to a second film to provide an interior space between the first and second films, wherein the first and second films have different shrink characteristics so that at a selected temperature and direction the shrink tension of the first film is greater than the shrink tension of the second film; and an insulation material comprising aerogel within the interior space.

23. The insulation product of claim 22 wherein the interior space has a pressure less than the pressure outside of the interior space.

24. A method of insulating an object comprising: providing the insulation product of any of claims 22-23; heating the first film to activate the shrink characteristic of the first film and shorten the first film relative to the second film and reshape the article between the first and second films; and installing the insulation product around the object.