WO2014082011A1

WO2014082011A1 - Thermally protective cover and method of manufacture thereof

Info

Publication number: WO2014082011A1
Application number: PCT/US2013/071496
Authority: WO
Inventors: Srinivas Cherukupalli; Atanu ACHARYA; Raghvendra Singh PAL
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 2012-11-22
Filing date: 2013-11-22
Publication date: 2014-05-30
Anticipated expiration: 2015-05-22
Also published as: WO2014082014A1

Abstract

A thermally protective cover is provided for storage and transportation of temperature sensitive materials by using a good barrier for different modes of heat transfer (conduction, convection, radiation) along with incorporation of an active cooling mechanism. Also provided is a method of making a thermal protection cover by putting together the barrier layers for effective heat transfer.

Description

TITLE

THERMALLY PROTECTIVE COVER AND METHOD OF MANUFACTURE

THEREOF

FIELD OF THE INVENTION

The present invention relates to thermally protective cover for storage or transportation of temperature sensitive material which is to be maintained at or near their temperature at the time of packaging.

This invention also relates to a method of manufacture of thermal barriers for transport and storage of articles having improved thermal protection properties for temperature sensitive materials.

BACKGROUND OF THE INVENTION

The conventional means of shipping temperature sensitive materials such as pharma and bio -pharma products involves the use of an insulated box along with some cooling agent. These cooling agents are typically a frozen gel, dry ice, or glistening (wet) ice.

There are, however, several problems with the conventional approach.

First, the insulation material often does not degrade readily, leading to disposal problems. Styrofoam ® is one of the commonly used insulation material.

These problems are so severe that many countries ban the use of Styrofoam ®, thus severely restricting international shipments of biological materials.

Second, the cooling agents also present numerous practical problems in field use.

Specifically, gel systems are often too expensive for routine use and disposal. As for dry ice, the carbon dioxide gas evolved during shipment may be dangerous to personnel involved with packing and transportation of the shipment. Wet ice poses handling problems in packing, as well as leakage and product soaking problems.

Many previously existing shipping systems also suffer the disadvantage that they are not capable of maintaining the shipped product or payload within a target temperature range. Various biological products, such as platelets, whole blood, semen, organs and tissue, must be maintained above a predetermined minimum temperature and below a predetermined maximum temperature. Pharmaceutical products are also commonly required to be kept within a specified temperature range. Food products, flowers and produce frequently have preferred storage temperature ranges as well. Many known methods and systems for shipping such products are not able to keep temperatures within the desired range. The result of this practice is excessive cooling, frequently resulting in damage to the product.

Previously known methods and systems which are capable of maintaining a payload within a specified temperature range have been found to be unsuited to certain applications, unduly complex in practice, and/or prohibitively expensive.

Another problem often observed with conventional systems is failure to maintain the proper temperature over time, due to inadequate insulation and/or inadequate cooling pack capacity. Again, the end result is product damage.

The consequence of these observed shortcomings of conventional shipping systems is damage to the material being transported. For biomedical materials such as blood, blood products, pharmaceuticals, etc., loss of these products due to heat damage is critical because of the intrinsic financial value of these items and because of the potential health hazards that the use of compromised materials presents. Likewise, heat damage to various foods also presents both financial and health consequences.

The use of honeycomb or cellular structures inside walls is also widely discussed in the prior art. These structures are intended to be permanently affixed on the inner space between an exterior wall of a sheltered structure (such as a home or building) and the interior wall of the structure. Among prior art proposals are those of US3314846;

3547751; 4673600; 4865889; 5062751; 5171114; and USRE26444. Although such structural approaches could be adopted for minimizing convective heating of a cold sample during shipment, the cost of creating a container that incorporates the baffles is, to date is prohibitively expensive.

In addition, many of these baffled structures are commonly made of paperboard material, which must be treated to avoid disintegration from contact with moisture commonly forming near a cold object through condensation of water from air. US

2703770 describe a honeycomb structure created using plastic material and alternating heat sealing dots. The process for the use of such an approach, however, is extremely slow as the rate of the machine is limited by the inherent time required for heat sealing the dots. While increased rates may be achieved through multiple heat sealing fixtures, such methods prove expensive and difficult to assure proper quality control.

Vaccines and serums are expected to be maintained, in most cases, between 2 - 8

°C for 48 - 100 hours (depending on destination) during shipment through air or road. This is typically achieved by using a Styrofoam® box filled with adequate gel packs to maintain the required product temperature. However, with increasing exposure to ambient conditions, the gel pack efficiency decreases and thereby puts the product at risk of losing potency .

Therefore, there is a need to have thermal protective cover which significantly increases the time at which the product stays between a required temperature range and which is easy to manufacture, use and is also more cost effective. This would result in better protection for temperature sensitive products with more economical solutions for transporting and preserving them.

OBJECTS OF THE INVENTION

Accordingly, an object of the invention is to provide a good barrier for different modes of heat transfer (conduction, convection, radiation) along with incorporation of an active cooling mechanism.

Another object of the present invention is to provide a thermal protection cover having improved air permeability to protect temperature excursions during shipment of pharma /bio pharma products or other such temperature sensitive materials through land, air or water.

Another object of the present invention is to provide a thermal protection cover containing suitable barrier of single or a plurality of layers at different levels of the packaging system.

Still another object of the present invention is to provide a thermal protection cover containing an active insulation system which proactively preempts energy absorption by the package and also helps in further decreasing the risk of temperature deviation. SUMMARY OF THE INVENTION

An aspect of this invention is a thermally protective cover for storage or transportation of temperature sensitive material comprising a plurality of layers with at least one radiative barrier layer and at least one insulation layer; wherein the thermally protective cover has air permeability of at least 25 standard Gurley seconds per 100 cc of air.

Additional features and advantages of the present invention are described herein, and will be apparent from the detailed description.

BRIEF DESCRIPTION OF DRAWINGS

The present invention should become apparent from the following description when considered in conjunction with the accompanying drawings, in which:

Figure 1 is a cross-sectional view of the thermal protection cover.

Figure 2 is a data logger chart comparing temperature profiles of Tyvek® 1048 A against Metalized Tyvek®.

Figure 3 is a data logger chart comparing temperature profiles of Tyvek® 1048 A against T 100 and T700.

Figure 4 is a data logger chart comparing temperature profiles of Tyvek® 1048 A against Tyvek® NR.

Figure 5 is a data logger chart comparing temperature profiles of Tyvek® 1048 A against Tyvek® NR

Figure 6 is a data logger chart comparing temperature profiles of Tyvek® 1048 A against metalized Tyvek®.

Figure 7 is a data logger chart comparing temperature profiles of Tyvek® 1048 A against Tyvek® with SAP (super absorbent panel).

Figure 8 is a data logger chart comparing temperature profiles of Tyvek® 1048 A with vacuum insulation panel against Tyvek® alone. DETAILED DESCRIPTION OF THE INVENTION

An aspect of this invention is a thermally protective cover for storage or transportation of temperature sensitive material comprising a plurality of layers with at least one radiative barrier layer and at least one insulation layer; wherein the thermally protective cover has air permeability of at least 25 seconds per 100 cc of air as measured by the Gurley method.

In one embodiment of the present invention, the radiative barrier layer has a reflectivity of at least 20% in the wavelength region of 100 - 3000 nm and an emissivity of at least 0.05.

In another embodiment of the present invention, the radiative barrier layer is selected from a group consisting of metal foils, non-wovens, polymeric microporous membranes, perforated polymeric sheets, porous cellulosic sheets or combinations thereof.

In still another embodiment of the present invention, the non-woven is a polyolefm flash spun non- woven having a reflectivity of at least 50 % in the wavelength region of 400-700 nm.

In another embodiment of the present invention, one of the radiative barrier layers is at least partially coated or adhered or laminated or adjacent or present as a distinct layer with respect to the outer most radiative barrier.

In yet another embodiment of the present invention, the insulation layer has an R- value per inch of 0.1-50 ft² °F/ (Btu/h).

In still another embodiment of the present invention, the insulation layer is selected from a group such as a fibrous polyester wool, nitrile rubber foam, nitrile rubber blended with polyvinyl chloride foam, cross-linked polyethylene foam, polyurethane foam, polystyrene foam, water filled super absorbent polymer/polyacrylates, a vacuum panel having a honeycomb structure as a core layer or combination of these with metal foil, nonwovens, polymeric microporous membrane, porous cellulosic sheet and the like.

In one embodiment the invention is method for covering temperature sensitive material for storage or transportation with a thermally protective cover comprising the steps of covering temperature sensitive material with at least one insulation layer and at least one radiative barrier layer; wherein the thermally protective cover is air permeable.

In still another embodiment, the vacuum insulation panel comprising of a core and skin is manufactured by a method comprising the steps of enclosing the panel inside a non-permeable cover, evacuating air from the core layer of the panel, and sealing the non-permeable cover in a manner such that there would be no loss of vacuum thereby creating a vacuum insulated panel.

Another embodiment of the invention is the use of the thermally protective cover for pharma and bio-pharma industry, insulations for buildings, food and beverage industry, automobiles and the like.

For purposes of describing the features of the laminate described herein, the term "thermally protective" cover refers to an article which aids in protecting against thermal excursions of a product or the material to be thermally protected or transported;

the term "radiative barrier" refers to materials which allows for an efficient reflectivity of solar radiation;

the term "insulation layer" refers to a structure designed to reduce or minimize heat transfer there through;

the term "air permeability" refers to the time required for specific volume of air under unit pressure to pass through unit measured by standard Gurley method and expressed as seconds per 100 cc of air;

"reflectivity" refers to the ability to reflect electromagnetic radiation;

"emissivity" refers to the ability of a material to re-emit absorbed thermal energy as radiation;

"R-value" is defined as the thermal resistivity of a material as measured by a guarded hot plate instrument;

"reduced atmospheric pressure" refers to a condition of lowered concentration of air within a confined space as compared to atmospheric pressure. "Gurley method" is based on the principle that air is compressed by the weight of a vertical cylinder floating in a liquid. A test piece is in contact with the compressed air and the cylinder falls steadily as air passes through the test piece. The time for a given volume of air to pass through the test piece, i.e. the air resistance is measured and from this the air permeability is calculated.

Air cargo covers made from DuPont™ Tyvek® provide a high level of thermal protection from solar radiation to reduce the damaging effects of the heat. The reflective property of Tyvek® keeps the shipment naturally cooler than other covers on the market. The unique properties of Tyvek® allow for rapid cooling of the load when placed in chilled storage or cooling chambers, shortening cooling times.

DuPont™ Tyvek® Air Cargo Covers provide protection from heavy rains and are tear resistant, lightweight and easy to use. They also protect against airborne

contamination such as dust, pollens and bird droppings. The covers are white, providing a secondary visible cover to help reduce the potential of theft or tampering. Tyvek® Air Cargo Covers offer the utmost protection for pharmaceutical items, fruits, vegetables and fresh flowers. It is known that Tyvek® Air Cargo Covers generated an average of 15.4 °C lower temperatures when compared to an uncovered load when exposed to sun light and 9.2 °C lower when at ambient temperature. However, when compared to Aluminum bubble wrap, the difference is negligible.

Tyvek® alone as a thermal protective cover has not been found to be successful to provide a solution to the problem associated with temperature excursions during shipment of very temperature sensitive material such as vaccines. There is therefore a need to have a solution that affords protection for such requirements. The inventors found that introducing a suitable barrier to different modes of heat transfer as an outer cover or at different levels of the packaging system along with Tyvek® could provide the desired effect. An active insulation system which proactively preempts energy absorption by the package would also help in further decreasing the risk of temperature deviation.

Therefore the proposed solution has the following embodiments- 1. secondary barrier: Tyvek® microstructure allows for an efficient reflectivity of both UV and visible ranges of radiation. While only a small portion of UV radiation (320 - 400 nm) reaches earth surface, a significantly high energy density radiation is in the visible range (400 - 700 nm). This radiation once absorbed converts into lower energy (higher wavelengths) and re-emitted as infra-red (IR) radiation.

Tyvek® grades have reflectivity values of 85-95 % in 400 - 700 nm radiation, compared to about 50 % by Aluminum and 3 % by transparent stretch wrap. In the near to mid-IR region (700 - 2500 nm), Tyvek® has an average reflectivity of 50-65 %, while

Aluminum is slightly better with values of 75- 80 %. Therefore, a metalized Tyvek® (through coating, lamination, adhesion, or just adjacent layering), would act as a complete radiant barrier in comparison to any other competitive material and thereby offer effective solutions.

2. Convective barrier: Though both forced and natural convection currents can be limited in impact through use of a highly tortuous barrier (Tyvek® or metallic Tyvek®), other ways to limit any damage is to have a thicker insulation. This can be achieved through fibrous, open cell, or closed cell insulations (such as honey comb structures) - as have been in our proposed solution.

3. Conductive barrier: Conductive barriers have been incorporated through use of fibrous insulation (polyester and micro-denier polyester), open cell (polyethylene foam), and closed cell (Nitrile rubber, cross-linked polyethylene) insulation. Increasing thermal resistance is achieved through increasing the density or thickness of the insulating material.

4. Active insulation: Water has an extremely high heat capacity and can be used to 'soak' up incident energy before transferring the remnants to packaged goods. While water in liquid form can be used (unfrozen gel packs, packaged pouches etc.) they create hassles in handling (vertical panels can create uneven distributions) and risk of punctures and leaks. A super absorbent polymer (SAP) such as metallic salts of polyacrylate can bind with water molecules creating a gel that remains stable even in different physical orientations (vertical panels). Preliminary experiments have shown an advantage to using an active layer as described above in thermal protection of the product.

The present invention is intended to be used in pharma and bio-pharma industry.

In addition, its utility could span a wide range of applications including but not limited to insulations for buildings, food and beverage industry, automobiles, etc. wherein typical thermal barriers are currently used.

The following materials were used as barrier layers in the thermal protective cover of this invention:

Tyvek® 1048 A, a flash spun non woven high density polyethylene from E.I. DuPont de Nemours Company;

Metallized Tyvek®- a breathable, metalized product of Tyvek®;

T 100 =100 g /cm2 fibrous polyester wool;

T700 = 700 g /cm2 fibrous polyester wool; T300 = a 200 g/m² of fibrous micro-denier polyester wool (DuPont® Comformax®) with 100 g/m² of polyester wool;

T-NR = a 6 mm closed cell Nitrile Rubber foam (blended with about 40 wt % Poly vinyl chloride); and

MT-NR9= Metallised Tyvek® with 9 mm closed cell Nitrile Rubber foam, in

combination with certain convective, conductive and insulation materials.

Fig. 1 shows the cross section of the thermal protection cover describing the above mentioned barrier layers:

1. Outer radiative barrier

2. Primary conductive barrier

3. Inner radiative barrier

4. Secondary conductive barrier

5. Inner covering layer Fig. 2 is a data logger chart comparing temperature profiles of Tyvek® 1048 A against Metalized Tyvek®, wherein the curves are identified as:

1. Stretch wrap

2. Tyvek® 1048A

3. Metalized Tyvek®

Fig. 3 is a data logger chart comparing temperature profiles of Tyvek® 1048 A against T100 and T700 for temperature profiles below packaging sheet at ambient exposure of 27°C, wherein the curves are identified as:

1. Tyvek® 1048 A

2. T100

3. T700 Fig. 4 is a data logger chart comparing temperature profiles of Tyvek® 1048 A against Tyvek® NR for maximum ambient temperature of 40°C, wherein the curves are identified as:

1. Tyvek® 1048 A

2. Tyvek® NR

Fig. 5 is a data logger chart comparing temperature profiles of Tyvek® 1048 A against Tyvek® NR for average exposure temperature of 40° C in the absence of sunlight, wherein the curves are identified as:

1. Tyvek® 1048 A

2. Tyvek® NR Fig. 6 is a data logger chart comparing temperature profiles of Tyvek® 1048 A against metalized Tyvek® with closed cell insulation for maximum ambient temperature of 37°C, wherein the curves are identified as:

1. Tyvek® 1048 A

2. Metallic Tyvek® with closed cell insulation

Fig. 7 is a data logger chart comparing temperature profiles of Tyvek® 1048 A against Tyvek® with SAP (super absorbent panel) for maximum exposure temperature of 32°C in direct sunlight, wherein the curves are identified as:

1. Tyvek® 1048 A

2. Tyvek® SAP

Fig. 8 is a data logger chart comparing temperature profiles of Tyvek® 1048 A with vacuum insulation panel against Tyvek® alone within the range of 2-20 °C, wherein the curves are identified as:

1. Tyvek® 1048 A

2. Vacuum Insulation panel

METHODS USED

Air permeability of pallet cover was measured by an ISO 5636-5 method using a Gurley 4340 apparatus. The apparatus consisted of an opening for a flat-sheet sample to be inserted and clamped pneumatically. Upon clamping, a constant volume of air is passed through the test specimen at a particular applied pressure (specified by Gurley 4340 automatic densometer provided by Gurley Precision Instruments, Troy, NY, USA) and the time taken (in seconds) is displayed by the instrument to indicate the air permeability of the sample.

Average peak temperatures of pallets prepared in the below examples was measured using a iButton DS1921G-F5 data logger which can record air temperature for every 10 minutes with an accuracy of ± 0.5 °C . EXAMPLES

Example 1

A 750 x 750 x 750 mm³ pallet was prepared with 27, 3-ply corrugated packaging boxes and covered with Metallised Tyvek® grade by first applying a bottom cover, followed by a top cover, thereafter sealing the two using a double sided adhesive tape. Prior to placing the top cover, a data logger was taped on top of the top row, middle box. The Tyvek® (white) side of Metallised Tyvek® faced the sun during exposure. The pallets were exposed to ambient conditions (maximum ambient temperature 41 °C) for a period of at least 72 hours before analyzing the temperature profiles. The above sample showed an air permeability value of 1578 s per 100 cc of air as measured by Gurley method.

Comparative example la

A 750 x 750 x 750 mm³ pallet was prepared similar to example 1, except that pallet was covered with Tyvek® 1048 A with a data logger in position. The Tyvek® (white) side of Tyvek® 1048 A faced the sun during exposure. The above sample showed an air permeability value of 13.7 s per 100 cc of air as measured by Gurley method.

Comparative example lb

A 750 x 750 x 750 mm³ pallet was prepared similar to example 1, except that pallet was covered with a transparent polyethylene stretch wrap. The above sample did not show any air permeability with value greater than 50000 s per 100 cc of air as measured by Gurley method. As can be seen form Fig. 2, at average maximum ambient temperature of 41 °C, the data loggers indicated a average peak temperatures of 37 °C for Example 1 ; 44 °C for comparative example la and 80 °C for comparative example lb . Such a performance difference was observed over multiple repetitions of this experiment.

Example 2

Pallets of dimensions described in Example 1 were prepared with Tyvek® 1048A along with T100 (insulation layer). The bottom layer was spun bonded Polypropylene of about 100 g/m² basis weight. Data loggers were placed in each pallet as described in Example 1. The pallets were first conditioned at 20 °C for at least 6 hours, before placing them under a shaded region with no direct sun light exposure for at least 3 hours. The constant (3 hour period) average temperature of the shaded regions was 27 °C. At least 3 such cycles were carried out to obtain average temperature profiles. The above sample showed an air permeability value of 25 s per 100 cc of air as measured by Gurley method.

Example 3

Pallets of dimensions described in Example 1 were prepared with Tyvek® 1048 A and T700.The bottom layer was spun bonded Polypropylene of about 100 g/m² basis weight. Data loggers were placed in each pallet as described in Example 1. The pallets were first conditioned at 20 °C for at least 6 hours, before placing them under a shaded region with no direct sun light exposure for at least 3 hours. The constant (3 hour period) average temperatures of the shaded regions were 27 °C. At least 3 such cycles were carried out to obtain average temperature profiles. The above sample showed an air permeability value of greater than 25 s per 100 cc of air as measured by Gurley method.

Example 4 (comparative example with respect to examples 2 and 3)

Pallets of dimensions described in Example 2 and 3 were prepared with

Tyvek® 1048 A without any insulation layer. Data loggers were placed in each pallet as described in Example 1. The pallets were first conditioned at 20 °C for at least 6 hours, before placing them under a shaded region with no direct sun light exposure for at least 3 hours. The constant (3 hour period) average temperatures of the shaded regions were 27 °C. At least 3 such cycles were carried out to obtain average temperature profiles.

The above sample showed an air permeability value of 13.7 s per 100 cc of air as measured by Gurley method. As shown in Fig. 3 at 27 °C exposure, T100 and T700 show much slower rate of temperature changes as compared to Tyvek® 1048 A alone. Also with insulation layers, air permeability typically decreases. Example 5

Pallets of dimensions described in Example 1 were prepared with Tyvek® 1048 A and T-NR. The bottom layer was spun bonded Polypropylene of about 100 g/m² basis weight. The pallets were exposed under direct sun light. Data loggers were placed underneath the cover on top of top row middle box and also in top row corner box with 1.7 kgs of gel packs (> 95 wt % water) to simulate the product. The above sample showed an air permeability value of 13545 s per 100 cc of air as measured by Gurley method. Example 6 (comparative example with respect to example 5)

Pallets of dimensions described in Example 5 were prepared with Tyvek® 1048 A without any insulation layer. Data loggers were placed in each pallet as described in Example 1. The pallets were placed under direct sun light. Data loggers were placed underneath the cover on top of top row middle box and also in top row corner box with 1.7 kgs of gel packs (> 95 wt % water) to simulate the product. The above sample showed an air permeability value of 13.7 s per 100 cc of air as measured by Gurley method. Under direct sunlight, Fig. 4 indicates the improved performance of T-NR over Tyvek® 1048 A alone. The product temperatures were nearly 5 °C lower for T-NR over Tyvek® 1048 A and moreover, time to reach the peak temperature was offset by at least 4 to 5 hours - a significant impact for thermal protection of perishable goods. Also with insulation layers, air permeability typically decreases.

Example 7

Pallets of dimensions described in Example 1 were prepared with Tyvek® 1048 A and T-NR. The bottom layer was spun bonded Polypropylene of about 100 g/m² basis weight. The pallets were first conditioned at 20 °C for at least 6 hours, before placing them under a shaded region with no direct sun light exposure for at least 3 hours. Data loggers were placed underneath the cover on top of top row middle box and also in top row corner box with 1.7 kgs of gel packs (> 95 wt % water) to simulate the product. The above sample showed an air permeability value of 13545 s per 100 cc of air as measured by Gurley method. Example 8 (comparative example to example 7)

Pallets of dimensions described in Example 7 were prepared with Tyvek® 1048 A without any insulation layer. The bottom layer was spun bonded Polypropylene of about 100 g/m² basis weight .Data loggers were placed in each pallet as described in Example 1. The pallets were first conditioned at 20 °C for at least 6 hours, before placing them under a shaded region with no direct sun light exposure for at least 3 hours. Data loggers were placed underneath the cover on top of top row middle box and also in top row corner box with 1.7 kgs of gel packs (> 95 wt % water) to simulate the product.

The above sample showed an air permeability value of 13.7 s per 100 cc of air as measured by Gurley method. Under shaded conditions, Fig. 5 indicates a much slower rate of temperature change for T-NR over Tyvek® 1048 A. Also with insulation layers, air permeability typically decreases. Example 9

Pallets of dimensions described in Example 1 were prepared with Metallised Tyvek® and MT-NR9. The bottom layer was spun bonded Polypropylene of about 100 g/m² basis weight The pallets were exposed to direct sun light for at least 100 hours and the product temperature profiles were recorded, as described in Example 3. The above sample showed an air permeability value of 15000 s per 100 cc of air as measured by Gurley method.

Example 10 (comparative example to example 9)

Pallets of dimensions described in Example 9 were prepared with Tyvek® 1048 A without MT-NR9. The pallets were exposed to direct sun light for at least 100 hours and the product temperature profiles were recorded, as described in Example 3.

The above sample showed an air permeability value of 13.7 s per 100 cc of air as measured by Gurley method. Fig. 6 shows the results with MT-NR9 showing an average of nearly 8 °C lower peak temperature and a time lag of 5 or more hours, in comparison to Tyvek® 1048A alone. Also with insulation layers, air permeability typically decreases. Example 11

A 24 cm² sample of a super absorbent polymer (140 g/m2, Technical Absorbent, UK) was wet with 200 cc of water and made into a panel by completely covering it with stretch wrap. Five such panels were adhered together to create a cover (sans bottom side) for a 250 x 250 x 250 mm³ 3-ply corrugated box, over which a Tyvek® 1048A cover was placed and sealed (T-SAP). Data logger was placed inside the box to record temperature. The boxes were exposed to direct sun light for about 50 hours. The above sample showed an air permeability value of greater than 50000 s per 100 cc of air as measured by Gurley method.

Example 12 (Comparative example to example 11)

A 250 x 250 x 250 mm³ 3-ply corrugated box was covered with Tyvek® 1048A alone and used as reference. The boxes were exposed to direct sun light for about 50 hours. The above sample showed an air permeability value of 13.7 s per 100 cc of air as measured by Gurley method. Fig.7 shows the temperature profiles. The T-SAP cover shows a slightly lowered temperature but with a temperature lag of at least 4 hours in comparison to Tyvek® 1048 A alone.

Example 13

20 gel packs were conditioned in a freezer (-17 °C) and arranged inside along the sides, top, and bottom of a corrugated box containing 2 gel packs conditioned at 2 to 8 °C. This assembly was placed inside the Styrofoam box (with outer dimensions of approximately 50 cm x 40 cm x 40 cm) to create an atmosphere of low temperature suitable for shipping biopharmaceutical or perishable goods. A panel consisting of paper skin and a paper honeycomb core of 12" width, 15 mm height, and wall thickness of 2 mm was placed inside a bi-axially oriented Polypropylene pouch previously sealed on 3 sides, and a lower atmospheric pressure condition was created. After reduction of air pressure, the open side was thermally sealed without allowing air ingress. Multiples of such panels were then attached through adhesive tape to adequately fit all sides of the Styrofoam box. Over this panel, a composite cover of the following layers stitched together was laid upon the panels and Styrofoam box ('protected') -

• Tyvek® 1048 A outer cover

• 6 mm Nitrile rubber closed cell foam

· 20 micron thick laminated Aluminum foil

Spun bonded Polypropylene inner cover

The box was exposed to ambient conditions with an average temperature of 25 °C. Data loggers were imbedded in the box to continuously record temperature and this data was analyzed after 100 hours of exposure. The above sample showed an air permeability value of greater than 50000 s per 100 cc of air as measured by Gurley method.

Example 14 (comparative example to example 13)

A Styrofoam box with gel pack contents as described in example 13 was prepared without any protective cover. The box was exposed to ambient conditions with an average temperature of 25 °C. Data loggers were imbedded in the box to continuously record temperature and this data was analyzed after 100 hours of exposure.

As seen from Fig. 8, substantial differences, greater than 40 hours, were observed between the two boxes at a particular product temperature within the range of 2-20 °C.

Claims

1. A thermally protective cover for temperature sensitive material comprising a plurality of layers with at least one radiative barrier layer and at least one insulation layer; wherein the thermally protective cover has air permeability of at least 25 seconds per 100 cc of air as measured by the Gurley method.

2. The thermally protective cover of claim 1, wherein at least one of the radiative barrier layers has a reflectivity of at least 20% in the wavelength region of 100 - 3000 nm and an emissivity of at least 0.05.

3. The thermally protective cover of claim 1, wherein at least one of the radiative barrier layers is selected from the group consisting of metal foils, non-wovens, polymeric microporous membranes, perforated polymeric sheets, porous cellulosic sheets and combinations thereof.

4. The thermally protective cover of claim 3, wherein, the non- woven is a polyolefm flash spun non- woven having a reflectivity of at least 50 % in the wavelength region of 400-700 nm.

5. The thermally protective cover of claim 1, wherein at least one of the radiative barrier layers is selected from the group consisting of a partially coated layer, a layer adhered to the outer most radiative barrier layer, a layer laminated to the outer most radiative barrier layer, a layer adjacent to the outer most radiative barrier layer and present as a distinct layer with respect to the outer most radiative barrier layer.

6. The thermally protective cover of claim 1, wherein the insulation layer has an R- value per inch of 0.1-50 ft² °F/ (Btu/h).

7. The thermally protective cover of claim 6, wherein the insulation layer is selected from the group consisting fibrous polyester wool, nitrile rubber foam, nitrile rubber blended with polyvinyl chloride foam, cross-linked polyethylene foam, polyurethane foam, polystyrene foam, water-filled super-absorbent

polymer/polyacrylates, and a vacuum panel having a honeycomb structure in combination with one of the group consisting of metal foil, nonwovens, polymeric microporous membrane and porous cellulosic sheet.

8. A thermally protective cover, comprising an outer radiative barrier,

a primary conductive barrier,

an inner radiative barrier,

a secondary conductive barrier and

an inner covering layer.

9. A thermally protective cover, comprising

an outer cover of flash spun nonwoven high density polyethylene, a layer nitrile rubber closed cell foam,

a layer of laminated aluminum foil and

an inner cover layer of spun bonded polypropylene.

10. A method for covering temperature sensitive material for storage or transportation with a thermally protective cover comprising the steps of covering temperature sensitive material with at least one insulation layer and at least one radiative barrier layer; wherein the thermally protective cover is air permeable.

11. A vacuum insulation panel comprising of a core and skin is manufactured by a method comprising the steps of enclosing the panel inside a non-permeable cover, evacuating air from the core layer of the panel, and sealing the non-permeable cover in a manner such that there would be no loss of vacuum thereby creating a vacuum insulated panel.

12. The use of the thermally protective cover of claim 1 in areas selected form the group consisting of the pharmaceutical industry, the bio-pharmaceutical industry, the food and beverage industry, automobiles and insulations for buildings.