FR2625980A1 - INSULATING MATERIAL AND ISOTHERMAL PROTECTIVE PACKAGING MADE FROM SUCH A MATERIAL - Google Patents

Abstract

Insulating material comprised of an insulating intermediary layer (1) coated on both faces with a reflecting material sheet (2, 3) characterized in that the intermediary insulating layer (1) is provided with perforations (4) regularly distributed throughout its surface and extending throughout its thickness, each perforation having a cross-section such that, as a function of the thickness (E) of the material, there is formed a space confined between the external reflecting sheets (2, 3), space wherein air is motionless.

Description

INSULATING MATERIAL AND ISOTHERMAL PROTECTIVE PACKAGING

REALIZED FROM SUCH A MATERIAL.

  The present invention relates to a new type of insulating material in the form of a thin sheet or plate; it also concerns

  a new type of packaging made from this material

  laugh. To date, many materials are used

  to make insulating sheets or plates used

  particularly for the production of packaging allowing

  as long as ensuring the isothermal protection of various products, such as in particular pharmaceuticals, foodstuffs. Among these materials, mention may be made of

  glass wool, rock wool, polystyrene ex-

  polyurethane or polyurethane foam

  thylene. While such plates can be used as is, in many cases it has been proposed to

  combine them on one or both sides with sheets

  reflective materials such as for example a layer of aluminized paper, an aluminum foil, a PVC film (or similar) metallized on one or both sides,

  in particular according to the vacuum metallization technique.

  In general, these sheets or plates are implemented by placing them "sandwiched" between two walls, in particular in the case of coolers or insulated bags.

  made of paper or PVC intended for the transport of

  jellies, pharmaceuticals, ..

  Such insulating materials are satisfactory for most applications but their thermal resistance is a function of their thickness, which leads

  relatively large product packaging

  therefore increase the production costs of such

  packaging. Furthermore, the sheets or plates iso-

  Lantes of thin thickness currently marketed allow thermal protection only for a limited time. Now it has been found, and this is the subject of the present invention, that it was possible to improve the thermal resistance of such insulating materials in large proportions for a given thickness, and this,

  without practically affecting the mechanical characteristics

  than packaging made from such materials.

  In general, the invention therefore relates to

  further development of insulating materials

  placed with an insulating intermediate layer coated on both sides with a sheet of reflective material, the material according to the invention being characterized in that the insulating intermediate layer has

  perforations, regularly distributed over its entire surface

  face and extending over its entire thickness, each

  hole having a section such that depending on the thickness of the material, a confined space is formed between the external reflecting sheets, space in

which air is still.

  According to the invention, the perforation section

  tions made in the intermediate (insulating) layer of the insulating complex according to the invention will be lower the thicker this layer, the section of the perforations being a decreasing function of the thickness. The ratio of the perforated surface to the total surface will be adapted according to the mechanical characteristics of the insulating material used. For example, for a sheet or plate material based on extruded polystyrene, this ratio should not exceed%.

  The external reflective sheets will be

  brought to the surfaces of the intermediate layer of ma-

  known way, for example by bonding or even, depending on the internal structure of the insulating layer, for example in the case where this insulating layer is based on a heat-bonding material, to achieve this association, by simple hot calendering, causing a surface fusion of the insulating layer and by

  following the bonding of the external reflective layers.

  As insulating material constituting the inter-

  ne, any material whose structure makes it possible to produce perforations having

a stable configuration.

  Preferably, however, it will be used as a layer

  insulating intermediate for cellulosic plastics

  rigid res such as extruded and expanded polystyrene

  polyurethane or polyethylene foams.

  The invention and the advantages which it brings will be

  however, better understood thanks to the examples of realizations

  tion given below & indicative and not limiting,

  and which are illustrated by the diagrams appended in the-

which:

  - Figure 1 is a schematic perspective view

  exploded tive showing the structure of an insulating material according to the invention; - Figure 2 shows a new type of packaging, which is also part of the invention, produced at

from such material.

  If reference is made to the appended diagrams and more particularly to FIG. 1, the insulating material according to the invention is in the form of a

  sheet or plate comprising on the one hand an insulating layer

  insulating intermediate (1), generally thin (between two and twelve millimeters), this intermediate layer (1) being coated on its two faces with two sheets (2,3) based on reflective materials

  such as for example a metallized film under vacuum (re-

aluminum garment).

  According to the invention, the intermediate layer (2) has, over its entire thickness, perforations (4) regularly distributed and which cover approximately 25%

  de - Total area of said intermediate layer (1).

  The association of external reflective sheets (2,3)

  nes to the intermediate layer (1) is produced for example by gluing, taking care however not to

  seal the holes of the perforations with a film of glue

tions (4).

  Compared to a similar material without internal perforations, the thermal resistance

  overall such sheets or plates are found

  significantly improved as will be demonstrated by the three embodiments which follow, examples made from three materials having respectively: one of 0.027 W,

0.030 W,

0.035 W;

  - for the outer sheets (2,3) of reflective sheets based on a metallized aluminum film whose power E is 0.04 and corresponds to that

polished aluminum.

  The three materials according to the invention are

  differentiate by their thickness E which is respective-

  three millimeters, six millimeters and ten mil-

  limiters. In these three examples, the perforations (4) are in the form of cylindrical conduits whose diameters are identical and cover a surface

  variable of the material, since according to its resistance

  Mechanical strength taking into account the total surface of the relatively small thicknesses of the internal layer (1), one obtains in all cases confined spaces where the air is stationary. For lesser materials

  thickness, it could be considered to have per-

  larger section holes whereas on the other hand, for thicker materials, it will be necessary to adapt this section to obtain such

  confined spaces where the air is stationary.

262.5980

  Comparative thermal resistance tests are carried out for insulating complexes having no perforations and complexes according to the invention comprising perforations covering more or less 25% of the total surface. These tests are carried out using three insulators (body no 1, no 2, no 3, respectively)., The core (1) of body no 1 having a conductivity coefficient of 0.029

  W / m C, the souls of bodies 2 and 3 having coefficients

  conductivity cients of 0.030 and 0.035 W / m C.

  The thermal resistances of the different complexes are given by the following relationships: - in the case of the conduction R = e; - in the case of connection and radiation R = i with h = x 5.72-1) - (O2 / v 0.2 L \ 400) \ 400) -i_z -Ti _ t T4TZ

  T expressing the temperatures of the walls in K.

  Recall that the average (lambda) of immobile air

  bile is 0.025 W / moC at the temperatures considered.

  Under these conditions, the value of the surface exchange coefficient is given by the relation:

-4 -4 0.25

  he = 0.04 (2.86 -2.81 x (572 + 1.81) (2.86-2.81) = 0.750W / '2 C

  Here is the table giving the results.

  Resistance with perforation I Tobtal Thermal resistance (lambda) by thermal thickness without axrx kn arm t overall part of the Body n 'perforation perforated cores perforated W / mC m m2'C / W m OC / W Body nl 0.027 0.003 0.111 0.120 2.667 2.787 0.780 natural 0.006 0.222 0.240 2.667 2.917 0.896

0.010 0.370 0.400 2.667 3.067 1.044

  Body n2 0.030 0.003 0.090 0.120 2.667 2.787 0.764 nature 0.006 0.180 0.240 2.667 2.917 0.864

0.010 0.330 0.400 2.667 3.067 1.014

  Body n3 0.035 0.003 0.086 0.120 2.667 2.787 0.761

0.006 0.171 0.240 2.667 2.917 0.850

0.010 0.400 0.400 2.667 3.067 0.984

J.o uI Co C,

  It is therefore found, thanks to the material according to the invention,

  tion, that the overall thermal resistance is notable-

  ment, and all the more so since the complex is

thin.

  Thanks to such materials, it is possible to

  read, in particular in the case of thin complexes, isothermal packaging presented under

the form of sachets or envelopes.

  It is also possible to produce new types of packaging as illustrated in FIG. 2 and which comprise, on the one hand, a base (5) on which is likely to fit a cover (6). This base (5) has an internal partition (7) also at

  base of a complex according to the invention. In the room

  bre (8), can be arranged a heating or cooling source constituted by a solid or liquid body

  whose thermal capacity is adequate for the purpose sought

  ché, this heat capacity can be provided either by the mass heat of the body or by its heat

  latent of fusion or solidification.

  The combined use of this type of packaging with a pouch made of the same material and provided with a closure excluding any exchange between the indoor air and the ambient atmosphere, allows a double insulation of the contents of the packaging. inside and subtract it for a determined time from variations in the temperature of the atmosphere, since the product and its packaging, which can be called "primary", are kept in a medium at constant temperature by

  as a result of the presence and action of ther-

mique.

  The above examples clearly show the advantages

tages brought by the invention.

  Furthermore, the invention is not limited to the embodiments described above but it covers all the variants produced in the same spirit.

Claims (6)

  1 / Insulating material composed of an intermediate layer   insulating diary (1) coated on both sides with a sheet (2,3) of reflective material, characterized by   the fact that the insulating intermediate layer (1) pre-   has perforations (4), regularly distributed over its entire surface and extending over its entire thickness,   each perforation having a section such as in function   tion of the thickness E of the material, a confined space is formed between the external reflective sheets   (2,3), space in which the air is stationary.   2 / insulating material according to claim 1,   characterized in that the section of the perforations (4) produced in the insulating intermediate layer (1) is all the smaller the thicker this layer, this   section being a decreasing function of the thickness.   3 / insulating material according to one of claims   1 and 2, characterized in that the perforations (4) do not   do not yield 25% of the total surface of the material to an extruded polystyrene.   4 / Material according to one of claims 1 to 3,   characterized in that the reflective sheets ex-   dull (2,3) are related to the surfaces of the layer intermediate (1).   5 / Isothermal protective packaging characterized in that it is in the form of a closed enclosure, all the walls of which are produced from a   material according to one of claims 1 to 4.   6 / Isothermal protective packaging according to the re-   vendication 5, characterized in that it is in the form of an enclosure comprising a base (5) on which is likely to fit a cover (6), the base (5) comprising an internal partition (7) of my-   niere & define a room (8) inside which   a cooling or heating source can be placed, the product (9) being arranged in the upper room (10). DEPOSITOR: DELTA-FOAM   MANDATORY: LAURENT and WAR WAR