Patent ID: 12241304

FIG.1depicts a schematic representation of the spacer1according to the invention comprising a polymeric main body5with two pane contact surfaces7.1and7.2, a glazing interior surface8, an outer surface9, and a cavity10. The outer surface9has an angled shape, wherein the sections of the outer surface adjacent the pane contact surfaces7.1and7.2are inclined at an angle of α=45° relative to the pane contact surfaces7.1and7.2. This improves the stability of the main body5. A water- and vapor-tight barrier film14that reduces the heat transfer through the polymeric main body5into the glazing interior of an insulated glazing is applied on the outer surface9of the spacer1. The barrier film14comprises three polymeric layers of polyethylene terephthalate with a thickness of 12 μm and three metallic layers of aluminum with a thickness of 50 nm. The metallic layers and the polymeric layers are in each case applied alternatingly, with the layer of the barrier film14facing the outer interpane space of the insulated glazing in the installed state of the spacer being a metallic layer. The barrier film14is bonded to the main body5. The cavity10is suitable for being filled with a desiccant. The glazing interior surface8of the spacer I has openings12, which are made at regular intervals circumferentially along the glazing interior surface8to enable a gas exchange between the interior of the insulated glazing and the cavity10. Thus, any humidity present in the interior is absorbed by the desiccant11. The openings12are preferably implemented as slits with a width of 0.2 mm and a length of 2 mm. The material thickness (thickness) of the walls of the main body5is roughly the same circumferentially and is, for example, 1 mm. The main body has, for example, a height of 6.5 mm and a width of 15 mm.

The mixture from which the main body5ofFIG.1was extruded comprises styrene-acrylonitrile as a thermoplastic base material at a proportion of 30 wt.-% to 35 wt.-% glass fibers, as an elastomeric additive, a thermoplastic polyurethane (TPU) at a proportion of 2.0 wt.-%, and 1.0 wt.-% of a foaming agent. The main body5has pours in a size of 30 μm to 70 μm. The main body5had good mechanical strength, reduced thermal conductivity, and reduced weight. TPU as a thermoplastic polyurethane causes a substantial improvement of the elastic properties of the main body5such that the risk of fracture of the main body5under mechanical stress is reduced.

FIG.2depicts a sketched force-displacement diagram that was produced on the basis of compression tests with foamed spacers with various elastomeric additives compared with tests with an unfoamed spacer. The inventors carried out tests with various mixtures and a spacer according toFIG.1made therefrom. The straight lines obtained show a dependence on selection of the elastomeric additive as well as on the dosage of the elastomeric additive. The illustration inFIG.2is based on tests carried out by the inventors, with a generalization having been made in order to make a qualitative statement independent of the exact dosage of the elastomeric additive.FIG.2shows the following data series:

1: San

Data Series 1 with the designation SAN depicts the behavior of a main body made of styrene-acrylonitrile as a base material with 35 wt.-% glass fibers. The main body is not foamed. Data Series 1 serves as a Comparative Example.

A behavior according to Data Series 1 is shown by the main body made from a mixture of 98.5 wt.-% styrene-acrylonitrile (SAN) with a content of 35 wt.-% glass fibers, to which 1.5 wt.-% of a color masterbatch is added.

2: San+Tpu

Data Series 2 with the designation SAN+TPU (Example 2) illustrates the course of the force-displacement curve with the use of a foamed main body with SAN as a base material, 35 wt.-% glass fibers and thermoplastic polyurethane (TPU) as an elastomeric additive. For example, a mixture of 95.5 wt.-% styrene-acrylonitrile (SAN) with 35 wt.-% glass fibers, to which 2.0% TPU, 1.0% foaming agent, and 1.5 wt.-% of a color masterbatch are added.

3: San+Abs

Data Series 3 with the designation SAN+ABS (Example 3) represents the behavior of foamed main bodies based on styrene-acrylonitrile, 35 wt.-% glass fibers, and acrylonitrile-butadiene-styrene copolymer (ABS) as an elastomeric additive.

Exemplary for Data Series 3 is a mixture of 92.5 wt.-% styrene-acrylonitrile (SAN) with 35 wt.-% glass fibers, to which 8.0 wt.-% ABS, 1.0 wt.-% foaming agent, and 1.5 wt.-% of a color masterbatch are added.

4. San+Asa

Data Series 4 with the designation SAN+ASA (Example 4) represents the behavior of foamed main bodies based on styrene-acrylonitrile, 35 wt.-% glass fibers and acrylonitrile-styrene-acrylate (ASA) as an elastomeric additive.

Exemplary for Data Series 4 is a mixture of 89.5 wt.-% styrene-acrylonitrile (SAN) with 35-wt.-% glass fibers and 8.0 wt.-% ASA, to which 1.0 wt.-% foaming agent and 1.5 wt.-% of a color masterbatch are added.

The mixtures according to Comparative Example and the embodiments according to the invention of Examples 2, 3 and 4 were in each case fed as granules to the extruder and melted in the extruder at a temperature of 215° C. to 220° C. The melt was formed by a melt pump through a mold to form a spacer according toFIG.1. The still soft hollow profile is stabilized in a vacuum calibration tool and then passed through a cooling bath.

Using the specimens from Comparative Example, Example 2, Example 3, and Example 4, force/strain measurements were carried out by clamping the specimens between two test jaws and the test jaws were moved toward each other until the specimen breaks. The maximum force F that can be applied to the specimen until the specimen breaks can be seen in the force-displacement diagram ofFIG.2as the break in the straight line. The distance that the two test jaws must travel until the main body breaks can be read from the x-axis marked with the length dL.

In the force-displacement diagram ofFIG.2, it can be seen that using TPU as an elastomeric additive (Example 2), a higher maximum force F can be applied to the spacer before breakage occurs compared with the Comparative Example. In comparison, the maximum force achievable by ABS or ASA as an elastomeric additive (Examples 3 and 4) is slightly reduced compared to the Comparative Example; however, the test jaws can travel a longer distance.

The inventors' tests show that the use of an elastomeric additive increases the flexibility of the spacer.

FIGS.3aand3bdepict an insulated glazing2with the spacer1according to the invention ofFIG.1, wherein the gas- and vapor-tight barrier film14is not shown in detail.FIG.3adepicts a cross-section of the insulated glazing2, whileFIG.3bis a plan view.FIG.3bdepicts an overall view of the insulated glazing2ofFIG.3a. The spacers1are connected to one another at the corners of the insulated glazing2by corner connectors17. The spacer1according to the invention is attached circumferentially between a first pane15and a second pane16via a sealant4. The sealant4connects the pane contact surfaces7.1and7.2of the spacer1to the panes15and16. The cavity10is filled with a desiccant11. Molecular sieve is used as the desiccant11. The glazing interior3adjacent the glazing interior surface8of the spacer1is defined as the space delimited by the panes15,16and the spacer1. The outer interpane space13adjacent the outer surface9of the spacer1is a strip-shaped circumferential section of the glazing, which is delimited by one side each of the two panes15,16and on another side by the spacer1, and its fourth edge is open. The glazing interior3is filled with argon. A sealant4that seals the gap between pane15,16and spacer1is introduced in each case between one pane contact surface7.1or7.2and the respective adjacent pane15or16. The sealant4is polyisobutylene. In the outer interpane space13, an outer seal6that serves to bond the first pane19and the second pane20is applied on the outer surface9. The outer seal6is made of polysulfide. The outer seal6ends flush with the pane edges of the first pane15and the second pane16.

FIG.4depicts a flow chart of a possible embodiment of the method according to the invention for producing a spacer comprising the steps:I Providing a mixture of at least thermoplastic polymer as base material, elastomeric additive, reinforcing agent, and foaming agent,II Melting the mixture in an extruder at a temperature of 200° C. to 240° C.,III Decomposing the foaming agent under the effect of temperature,IV Shaping the melt through a mold to form a spacer main body,V Stabilizing the spacer, andVI Cooling the spacer.

Preferably, in step IV, a gas- and vapor-tight barrier film is attached by adhesive bonding to the outer surface and at least to sub-regions of the pane contact surfaces.

LIST OF REFERENCE CHARACTERS

1spacer2insulated glazing3glazing interior4sealant5polymeric main body6outer seal7pane contact surfaces7.1first pane contact surface7.2second pane contact surface8glazing interior surface9outer surface10cavity11desiccant12openings13outer interpane space14gas- and vapor-tight barrier film15first pane16second pane17corner connector