DD291975A5 - USE OF A SELECTIVE ZEOLITHIC DRYING AGENT - Google Patents

Abstract

The invention relates to the use of a selective zeolitic desiccant in spacers of insulating glass and glazing units filled with air and / or exhaust gases. In addition to complete selectivity of the water vapor adsorption desiccant should have improved properties such as adsorption kinetics, capacity and granule resistance. The invention is characterized in that after calcination in a reactor in a cyclic mode at a volume ratio of potassium hydroxide to zeolite granules NaA of at least 1.0, preferably * at a flow rate of 0.005-0.015 m / s, based on the free cross section of the reactor , optionally to a crystallinity of at least 90%, treated zeolite granules having a pore volume in the secondary porosity of 0.18-0.25 cm 3 / g, of which at least 10%, resulting from pores having a pore diameter below 50 nm is used ; Air; Daemmgas; Insulating glass; water vapor adsorption; Capacity; Granule strength; potassium hydroxide; zeolite granules; Pore volume; Sekundaerporositaet; Pore diameter}

Description

The desiccant used according to the invention with high selectivity towards nitrogen and other insulating gases, which can be produced in the granule size between 0.5 and 3.0 mm, is characterized equally by very good adsorptive and mechanical properties. Surprisingly, it has been found that in Hen according to the invention used granules for use in insulating glass and glazing units and decisive parameters such as Wasserdampfadsorptionskapazität and kinetics also improved strength properties - expressed by a very low Mahlabrieb and dust content - are achieved in a small ball granules. This will be demonstrated by the examples below.

embodiment

For comparative investigations, the following two zeolite batches are prepared:

- KNa zeolite ball granules 1.0-2.0 mm with a pore volume in the secondary porosity of 0.285 cn ³ / g and a

D 10 value of 78 nm, prepared by deformation of KNaA zeolite powder with a K ⁺ ion molar content of 20% with 20% (by weight) Brandiser clay and calcination over 5 h at 873.15 K (batch I not according to the invention).

KNaA zeolite ball granules 1.0-2.0 mm with a pore volume of 0.210 cm ³ / g and a D 10 value of 36 nm, prepared by deformation of NaA zeolite powder with 20% (by weight) of kaolin Wolfka amination over 5 h at 873.15 K, treatment for 8 h in 10% KOH at 363.15 K and post-activation over 3h'bui723, 15K (lot II according to the invention).

example 1

Determination of equilibrium water vapor capacity

In a static adsorption apparatus, the batches I and II were tested for their absorption capacity for water vapor in g H ₂ O / 100 g zeolite according to TGL 22309, BI.7:

Batch I 16.8

Charged 18.6.

The charge II used according to the invention has a significantly higher capacitance value than the charge I, which is important for a longer service life of the insulating glasses.

Example 2

Determination of the temporal dependence of the adsorption of water vapor In the static adsorption apparatus, the time sequence of the adsorption of water vapor dsr batches I and II according to TGL 22309, BI.7, was determined:

Adsorption / n Adsorption capacity for water vapor chargell g H ₂ O / 100g zeolite 2.40 Batch I 9.50 1 1.75 16.00 6 7.30 18.50 12 11,50 18.60 18 13,90 18.60 24 15,80 18.60 48 16.70 72 16,80

The batch II used according to the invention thus achieves the capacity end value in a much shorter time than the charge I and thus reveals a better adsorption kinetics. This can be used for a faster adjustment of the end dew point in insulating glass.

Example 3

Determination of abrasion resistance

For the batches I and II, grinding abrasion values were determined according to TGL 22309, BI.6 (mass fraction):

Charge I 7,5%

Chargell 1.0%.

The batch II used according to the invention thus shows a much greater abrasion resistance than the batch I. This results in a significantly lower dust formation during the filling of the spacers of insulating glass as well as their handling.

Example 4

Determination of dust content

50g each of the 3h at 723.15K activated batches I and II were treated three times with 100ml benzene in an Erlenmeyer flask. The benzene was decanted off via an analysis filter (soft, wide-pored). The filter containing the dust was dried for 3 hours at 373.15K in a drying oven, then ashed for 3 hours at 873.15K and, after cooling, was weighed in a desiccator. The following dust contents were determined (mass fraction):

Batch I 0.35%

Chargell 0.05%.

The charge II used according to the invention thus has a significantly lower dust content than the charge I. This effect is advantageous, above all, during the filling process of the spacers of the insulating glass with the molecular sieve.

Example 5

Determination of Adsorption of Nitrogen In a static adsorption apparatus, 150 g each of zeolite batches I and II were contacted with an N ₂ volume of 0.81 for 1E minutes after lowering the pressure to 1 kPa in comparison with a NaA zeolite (Batch III) brought and determined after 12 h din pressure difference AP between the equilibrium pressure in the adsorption apparatus and the external pressure:

Zeolite charge pressure difference AP _{/ VP} ,

Batch I 1.3

Chargell 0.5

Batch III 18.0 (NaA zeolite)

The batch II used according to the invention thus has a very good selectivity of the water vapor adsorption to N :, similar to the KNaA zeolite prepared according to a known formulation (batch I), but clearly delimited from the unselective behavior of the zeolite NaA type. Thus, Deflexionserscheinungen be excluded in insulating glass.

Claims (1)

Use of a selective zeolitic desiccant having particular adsorptive and mechanical properties in spacers of insulating glass and glazing units filled with air and / or insulating gases for the purpose of keeping the glass internal surfaces free from clay and kaolin, calcination, alkaline recrystallization and ion exchange Type KNaA zeolite, characterized in that, after calcination in a reactor, in a cyclic mode at a volume ratio of potash to zeolite granules NaA of at least 1.0, preferably 2.0-3.0, at a flow rate of 0.005-0.015 m / s, based on the free cross-section of the reactor, optionally up to a crystallinity of at least 90%, treated zeolite granules having a pore volume in the secondary porosity of 0.18-0.25cm ³ / g, of which at least 10%, resulting from pores with a Porendurc diameter below 50nm is used. Field of application of the invention The invention relates to the use of a zeolitic drying or adsorbent with high selectivity and special adsorptive and mechanical properties in spacers of filled with air or insulating gases insulating glass and glazing units for the purpose of anti-fogging of the glass pane inner surfaces. Characteristic of the known state of the art The use of zeolitic drying agents (molecular sieves) in insulating glass and glazing units, which are filled with air and / or insulating gases to improve the thermal and / or acoustic insulation, primarily to ensure a fog retention of the glass inner surfaces, but also to avoid Deflexionen is known. High demands are placed on the zeolites used in terms of their adsorptive properties such as capacity, selectivity and kinetics and their mechanical properties such as sphere size, strength and low dust content. To achieve a high adsorption selectivity, ie adsorption of water vapor with complete exclusion of the adsorption of the air components or other insulating gases, the zeolite KNaA is required. The use of this type is described, for example, in DE-AS 2 540997 and DE-OS 2 5E9720. This also applies to a KNaA zeolite described in DE-OS 3705624, which is prepared by granulation of zeolite 4 Α powder with binder and dipotassium hydrogen phosphate. In DD-PS 205411, by reducing the K ⁺ ion content of 10 to 15 mol% in comparison with the conventional 3A type, the water vapor adsorption capacity is brought to a level comparable to that of the NaA type while maintaining the 3A type selectivity. Like the other technical solutions mentioned, this zeolite does not have the desired high adsorption kinetics, especially in the initial phase after infestation of insulating or glazing units with insulating gases. Also, the capacity is not always satisfactory and there are problems with the granule strength. The associated dust formation is disadvantageous when filling the spacers of the insulating glass or in the manipulation with the same. Object of the invention The aim of the invention is to use a zeolitic desiccant in spacers of filled with air or other insulating gases insulating glass and glazing units, which in addition to complete selectivity has improved properties such as adsorption kinetics, water vapor capacity and Granulatfestiykeit. Explanation of the essence of the invention It is an object of the present invention to provide a zeolitic desiccant based on KNaA type zeolite prepared and activated by deformation with clay or kaolin, calcination, alkaline recrystallization and ion exchange during production and regeneration, and preferably for improving heat and / or sound insulation insulating glass filled with insulating gases and glazing units, which in addition to complete selectivity of the water vapor adsorption to air or the insulating gases has improved properties such as adsorption kinetics, capacity and granule resistance. The object is manufactured according to the invention with a by deformation with clay or kaolin, calcination, alkaline recrystallization and ^ ion exchange and activated zeolite achieved type KNaA, ο ate a ^r after Kalzinie ung in a reactor, in circulation mode at a volume ratio of potassium hydroxide to Zeolite granules NaA of at least 1.0, preferably 2.0-3.0, at a flow rate of 0.005-0.015 m / s, based on the free cross section of the reactor, optionally up to a crystallinity of at least 90%, treated zeolite granules with a pore volume in the secondary porosity of 0.18-0,25cmVg, of which at least 10%, resulting from pores having a pore diameter below 50nm is used (Hg porosimetry to 20nm).