METHOD FOR MANUFACTURING A COMPOSITE ELEMENT FOR VACUUM INSULATION ELEMENTS

Abstract

The present invention relates to a method for manufacturing a composite element comprising a single- or multi-part core and an envelope which are in a force fit combination with each other, at least comprising providing a single- or multi-part core of an evacuable organic material; at least partly enveloping the core with an envelope to obtain a composite element precursor; and treating the composite element precursor for a period leading to an at least partial softening of the evacuable organic material and of the envelope surface apposing the core. The present invention further relates to composite elements obtained or obtainable by a method of the present invention and also to the method of using a composite element of the present invention as a vacuum insulation panel or as a thermal insulation material.

Claims

1. A method for manufacturing a composite element comprising a single- or multi-part core and an envelope which are in a force fit combination with each other, the method comprising: at least partly enveloping a single- or multi-part core of an evacuable organic material with an envelope to obtain a composite element precursor, wherein an envelope surface apposing the core comprises a thermoplastic material; treating the composite element precursor for a period leading to an at least partial softening of the evacuable organic material and of the envelope surface apposing the core.

2. The method according to claim 1, wherein the treating comprises a heat treatment via heating, infrared or ultrasound.

3. The method according to claim 1, wherein the treating comprises a heat treatment and pressing the envelope against the core.

4. The method according to claim 1, further comprising, before the treating: (a) evacuating the composite element precursor; (b) closing the envelope to obtain an evacuated composite element precursor.

5. The method according to claim 1, wherein the treating is carried out for a period in the range from 2 seconds to 30 minutes.

6. The method according to claim 1, wherein the single- or multi-part core has a plate-shaped configuration.

7. The method according to claim 1, wherein the evacuable organic material is selected from the group consisting of an organic aerogel, an organic xerogel and a rigid organic foam.

8. The method according to claim 1, wherein the envelope has a multilayered construction.

9. The method according to claim 1, wherein the envelope surface apposing the core comprises a thermoplastic material selected from the group consisting of a polyethylene and a polypropylene.

10. The method according to claim 1, wherein the envelope is diffusiontight.

11. The method according to claim 1, wherein the envelope has a DIN 53380 gas permeability of less than 1 cm.sup.3/(m.sup.2d).

12. The method according to claim 1, wherein the envelope has a DIN 53380 water vapor permeability of less than 1 g/(m.sup.2d).

13. A composite element obtained by the method of claim 1.

14. (canceled)

15. A vacuum insulation panel, comprising a composite element manufactured by the method of claim 1.

16. A thermal insulation material, comprising a composite element manufactured by the method of claim 1.

Description

EXAMPLES

1. Production Example

[0103] The following foil was used:

[0104] V08621 foil from Hanita Coatings RCA Ltd:

[0105] Three plies of metallized polyester film with one LLDPE seal layer

1.1 Example 1

Producing a Xerogel

[0106] The following compounds were used:

[0107] Components: [0108] oligomeric MDI (Lupranat M50) having an NCO content of 31.5 g per 100 g to ASTM D-5155-96 A, a functionality in the range from 2.8 to 2.9 and a viscosity of 550 mPa.Math.s at 25 C. to DIN 53018 (hereinafter compound M50). [0109] 3,3,5,5-tetraethyl-4,4-diaminodiphenylmethane (hereinafter MDEA)

[0110] Catalyst: dimethylpiperazine

[0111] 56 g of compound M50 were dissolved in 210 g of acetone in a glass beaker at 20 C. under agitation. 8 g of the compound MDEA, 1 g of dimethylpiperazine and 2 g of water were dissolved in 210 g of acetone in a second glass beaker. The two solutions from step (a) were mixed to obtain a clear mixture of low viscosity. The mixture was left to cure for 24 hours at room temperature. Thereafter, the gel was moved from the glass beaker and liquid (acetone) was removed by drying at 20 C. for 7 days.

[0112] The xerogel obtained had a compressive strength of 0.202 N/mm.sup.2 coupled with a density of 117 kg/m.sup.3.

[0113] Its thermal conductivity was 5.5 mW/m*K at the 3.6 * 10-4 mbar applied pressure to seal the foil (Hanita V08621).

1.2 Example 2

Producing an Open-Cell Rigid Polyurethane Foam

[0114] The following compounds were used: [0115] Polyol A: polyether alcohol formed from sucrose, glycerol and propylene oxide, hydroxyl number 490 [0116] Polyol B: polyether alcohol formed from propylene glycol and propylene oxide, hydroxyl number 105 [0117] Polyol C: polyether alcohol formed from propylene glycol and propylene oxide, hydroxyl number 250 [0118] Additive 1: Tegostab B 8870 silicone stabilizer from Evonik [0119] Additive 2: Ortegol 501 cell opener from Evonik [0120] Catalyst 1: Polycat 58 (Air Products) [0121] Catalyst 2: potassium acetate in ethylene glycol (BASF) [0122] Isocyanate: polymer MDI (Lupranat M70, BASF)

[0123] The recited raw materials were used to prepare a polyol component, which was reacted with the isocyanate. The amounts of the starting materials used are found in table 1. Mixing took place in a mix head. The reaction mixture was exported into a lab mold having the side lengths 418*700*455 mm and left to cure therein.

TABLE-US-00001 TABLE 1 employed amounts of starting materials Component Parts by weight polyol A 44.10 polyol B 44.10 polyol C 9.15 water 0.55 stabilizer 0.90 catalyst 1 0.50 catalyst 2 0.70 cell opener 1.80 cyclopentane 9.50 isocyanate 194 index 244

[0124] Test specimens measuring 19*19*2 cm were sawn out of the rigid foam blocks, packed into a gastight foil (Hanita V08621) and the foil was sealed following evacuation to pressures below 0.1 mbar.

[0125] The thermal conductivity was 7.7 mW/m*K at the 3.5 * 10-4 mbar applied pressure to seal the foil (Hanita V08621).

1.3 Example 3

Producing an Aerogel

[0126] The following compounds were used:

[0127] Components:

[0128] Oligomeric MDI (Lupranat M200) having an NCO content of 30.9 g per 100 g to ASTM D-5155-96 A, a functionality in the region of three and a viscosity of 2100 mPa.Math.s at 25 C. to DIN 53018 (hereinafter compound M200). [0129] 3,3,5,5-Tetramethyl-4,4-diaminodiphenylmethane (hereinafter MDMA)

[0130] Catalyst: Dabco K15 (potassium ethylhexanoate dissolved in diethylene glycol (85%))

[0131] 48 g of compound M200 were dissolved in 210 g of acetone in a glass beaker at 20 C. under agitation. 12 g of the compound MDMA, 2 g of Dabco K15 and 4 g of water were dissolved in 210 g of acetone in a second glass beaker. The two solutions from step (a) were mixed to obtain a clear mixture of low viscosity. The mixture was left to cure at room temperature for 24 hours. The gel monolith was removed from the glass beaker and transferred into a 250 ml autoclave, which was subsequently closed. The monolith was dried in a CO.sub.2 stream for 24 h. The pressure (in the drying system) was between 115-120 bar; the temperature was 40 C. At the end, the pressure in the system was let down to atmospheric at a temperature of 40 C. in a controlled manner in the course of about 45 minutes. The autoclave was opened and the dried monolith was removed. The thermal conductivity of the aerogel thus obtained was 17.5 mW/m*K at 10 C.

2. Tests of Core/Foil Adherence

[0132] The sealing/bonding of the foil (Hanita V08621) to the core was effected using a press after heat treatment of the foil. The press parameters were 125 C. hot platen temperature, 3 minutes press time and 2 bar molding pressure.

[0133] The sealed samples were stored under standard conditions (23 C., 50% rh) for 24 h.

[0134] A pull-off test on the foil sealed onto the core was carried out in accordance with DIN EN ISO 527-1 and gave a maximum pull-off force of:

[0135] Example 1: 130 N

[0136] Example 2: 249 N

[0137] The example shows that the adherence between the core material and the seal layer has the effect that a force has to be applied in order to destabilize this composite.

[0138] Accordingly, the composite elements of the present invention exhibit improved stability.