Domestic and Foreign Window Weatherstripping – Main Distinctive Features

This article will cover solely the rubber EPDM-based weatherstripping, and later we will try to understand the differences between the rubber and TPE.

It is no secret that the market of the double-glazed windows is currently on the stage of its development, despite economic difficulties in the country.  It includes metal-and-plastic, aluminum and wooden window systems. The rubber weatherstripping is used in all the systems. The most well-know window-systems, such as REHAU,Salamander,Veka, Aluplast, that nowadays comprise a group of companies holding the industry benchmark, produce all the components of the systems, including the rubber weatherstripping.

There is a huge number of small and medium-sized manufacturers of metal-and-plastic and other systems. The vendors that produce the industrial rubber goods produce their products exactly for this market segment.  A market competition in this segment is quite considerable – there are products of Turkish, Chinese, Polish and Ukrainian manufacturers (it should be noted that “Kievguma” LLC in Brovary city is the only company in Ukraine that produces the rubber weatherstripping for the window systems). It is often difficult to define the differences of the products manufactured by such vendors and the properties they have. The pricing should also be taken into account, — given the current economic situation, this issue makes the difference.

A rubber weatherstripping for the windows or doors is an element that ensures the hermetization of the installation and prevents from the drafts and heat losses in the premises. People often open windows and door, and under such conditions the weatherstripping is constantly “in motion” – it expands when the window is opened and contracts when it is closed.

Thus, the weatherstripping is subject to strict requirements in terms of the physical properties (permanent deformation, pressing force etc.)

Today we will try to compare some of indicators of the weatherstripping of different vendors on the example of Poland. Turkey, Ukraine, a model that will be used for the test is K-001 model (the so-called “frame ledge”). 

Though the regulatory and technical documentation defines critical tests (extension tests, tests on breaking strength under high or low temperatures  etc.), let’s try to compare the weatherstrippings in terms of resistance to deformation under usual conditions – at room temperature of + 20-25 С.

We will consider a knotting with the same applied force for the period of 48 hours 

as a deforming factor. Possibly this method is not technically correct, but it can display the real features of the weatherstripping of different manufacturers.

So, let’s take the weatherstripping of the same  type and length (30 cm) and tie them in a knot, and then leave them in the room for two days. 


In 48 hours, we will untie the samples and put them on the sheets of paper with the length markings.


We see, that the zones of permanent deformation of the sample can clearly be seen on the products of the Turkish and Polish  production.

And now lets check these weatherstrippings in more 24 hours. 


There is a permanent deformation, as well as the changes of geometrical properties lengthwise, before retrieval of the original length, on the sample of the Polish product. The permanent deformation can also be seen on the Turkish weatherstripping. The sample of “Kievguma” LLC product doesn’t have any of these deviations.

According to requirements of the technical regulations, all the samples are in compliance with the “permanent deformation” indicators, but, on the other hand, it is possible that the Turkish and Polish weatherstripping could eventually have problems with hermetization of the system during its deployment.   

And now let’s consider other indicators: the weight of the linear meter, geometry of profile of the product and the odor.For weighing, we will take three meter-long cuts of each sample of all the manufacturers that we compare, and weigh these samples on the electronic scales.

Here is the result:

Sample Poland, g. Turkey, g.    Ukraine      (Kievguma)
№1 42,21 41,18 45,48
№2 44,28 42,59 43,96
№3 43,90 42,06 46,01
Average deviation.,% 4,30 2,70 2,20


As we see, the deviation of weight is falls within the requirements of technical regulations, i.e. ±10%.In fact, the weight of the product does not affect its end-user performance — it merely depends on technology of production, a form of a die and components of the rubber mix.

A technology used for producing the EPDM rubber weatherstripping is a technology of extrusion of profiles with subsequent vulcanization by hot air, microwave heating, infrared heating, or by the heating in the molten salts, a combination of these methods is also can be used.

“Kievguma” LLC applies the extrusion technology with vulcanization in the molten salts. Below we introduce a manufacturing line installed in “Kievguma” facilities, and display the basic stages, namely the extrusion through the die, passage through the sing with molten salts and subsequent winding in the cardboard packages. 


This technology has a number of advantages, namely:

-a uniform heating of the weatherstripping in the vulcanization zone, which guarantees the stability of the following indicators: framing, geometry of the product,  possibility of adjustment of the rubber mix, thus ensuring the necessary hardness, strength, elongation etc.

These indicators were represented in our article below on the illustrations 2 and 3. At the same time there is one weak point – the manufactured products have a strong rubber odor, and a customer often doesn’t like it (though this odor disappears within 3-5 days after the weatherstripping has been installed in the steel construction). There are different “flavouring agents” being used, but anyway the odor is stronger than in other technologies of weatherstripping production.

One more parameter to compare is a tear force. The tests shall be conducted on the tearing machine of ZMG1-250 type (Germany).

Again, let’s take three samples of a single type of the weatherstripping of each manufacturer and put them under test.

These are results we have got (a value of the tear force is in kg per second):

Sample Poland Turkey Ukraine (Kievguma)
№1 19,2 19,6 20,0
№2 19,4 19,0 19,8
№3 18,8 19,8 20,3
Average Indicator 19,13 19,47 20,03

We can see that the products of the mentioned manufacturers according to this indicator are in the same diapason and practically do not differ.

Let’s consider one more important parameter of these products – the profile geometry of the weatherstripping and its compliance with the blueprint of the manufacturer. In this case, the technical requirements stipulate the exact parameters of the possible deviations of the properties from the original ones. Taking into account the measurements of the weatherstripping units under test (ranging from 4.1-6.3 mm), the acceptable deviation is ± 0,5mm. We will measure and compare the products by applying the electronic profile projector PP3000 (Germany), which allows to make measurements with precision up to ten thousandth of mm. But it is worth noting that “hundredth” and “thousandth” deviation indices are possible when working with the solid materials (steel, stone etc.), while for the “soft” materials (such as rubber, silicon, polymeric products), the deviations are much bigger, but they are compensated by their elasticity and other useful properties.

Let’s make a parallel cuts of results for the tests of the K-001 samples

The first column is the images of the parallel cuts, and the second one is the picture with the basic sketch of the weatherstripping profile. 






As we see, the forms of all the weatherstripping units differ from the basic sketch. At the same time, the weatherstripping manufactured by “Kievguma” LLC is much closer to the basic sketch in terms of form and thickness of the walls – this ensures  higher stability of endurance, elongation and the minimal permanent deformation, as we have already seen based on results of the first test, in which we knotted the samples (Pic. 1-3).

So, let’s draw a conclusion. All the weathersrtipping has its deviation from the standard parameters, but they comply with the indicators stipulated by the technical requirements, so everyone should decide by himself which product one wants to deal with.  

The aim of this article is not to convince someone than one should use a single particular product, but merely to compare the end-user properties of the weatherstripping sold in Ukraine, and to inform the customers on the properties and quality indicators of these products. In the next article  we will describe and compare the products made of the TEP and rubber- their properties, usabilities, pros and cons. 



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