RU223987U1 - Indicator of loss of strength of building films - Google Patents

Abstract

The utility model relates to the field of construction, namely to means for determining the degree of loss of strength of films under the influence of ultraviolet radiation, used in construction and stored in areas unprotected from sunlight. The technical result is the ability to obtain reliable information about the strength characteristics of the films used and the residual life before they are covered with external building structures. The essence of the utility model is that the ultraviolet radiation indicator, intended for determining the degree of loss of strength of building films, is made in the form of a fragment of material with a color layer applied to its surface, while the fragment is made of polyester-based material, on the outer surface of which paint is applied yellow color. According to the utility model, the indicator is fixed in the immediate vicinity or on the building film itself, stretched over the outer surface of the building structure, and is intended to determine the permissible time of use of the building film.

Description

The utility model relates to the field of construction, namely to means for determining the degree of loss of strength of films under the influence of ultraviolet radiation, used in construction and located in places unprotected from sunlight.

A building film that is resistant to ultraviolet radiation is known (see patent RU No. 2780070 C1, published 09/19/2022). However, despite the increased resistance to UV radiation, the final resource and residual strength of the film used in construction is unknown.

A known ultraviolet radiation indicator is made in the form of a fragment of material with a color layer deposited on its surface with the ability to identify changes in the color of said layer as a result of exposure to sunlight and thus obtain information about the dose of solar radiation received depending on the change in color of the indicator layer (see US 2002117633 A1, pub., 08.29.2002).

The disadvantage of the known indicator is the inability to obtain information about the loss of strength of building films under the influence of direct sunlight, for example, before covering them with building structures. Since building films are destroyed under the influence of UV radiation, information about their residual strength is very important when making such a decision, since if the films that have lost their strength are covered with external building structures, they will not perform their functions, and replacing them will be difficult and expensive.

The technical problem is to eliminate the noted shortcomings.

The technical result consists in providing the ability to obtain reliable information about the strength characteristics of the films used and the residual life before they are covered with external building structures.

The technical problem is solved, and the technical result is achieved in that the ultraviolet radiation indicator, intended for determining the degree of loss of strength of building films, is made in the form of a fragment of material with a color layer applied to its surface, while the fragment is made of a polyester-based material, on the outer surface which is painted yellow.

The technical result is also achieved by the fact that the side of the indicator, on which no paint is applied, can be made of adhesive, covered with a removable protective material, for example, craft paper.

The technical result is also achieved by the fact that polymerized Simitry HD E toner can be used as paint.

The main destructive factor for building films is UV radiation. Films used in construction are covered with roofing or facade materials in the constructed object. But for some time they are exposed to direct sunlight. Therefore, all manufacturers indicate a certain period in days or months that films can be exposed to the open air. This period is conditional, because the amount of UV in different climatic zones and in different seasons is different (for example, in Krasnodar in summer and in Murmansk in winter). The level of ultraviolet radiation depends on geographic latitude. For example, the UV index for St. Petersburg in November-January is zero, in June-July - five. Therefore, a parameter in the form of a certain time period does not provide reliable information about the loss of consumer qualities of the film used. The correct thing to do is to measure the dose of UV radiation received and make a decision about the need to quickly cover it with other materials or about the unsuitability of its use based on the measured value.

The building film can be exposed to the open air during the period after it is laid on a building structure, for example, a roof, and before the film is covered with a roof. Depending on the time the film is exposed to the open air, its residual life also changes due to its loss of strength and changes in other qualities under the influence of ultraviolet radiation.

Based on the degree of burnout of the described indicator, one can judge the received dose of UV radiation and the residual strength of the building film used.

Applying an indicator layer directly to the film web during their production is inconvenient. So, during the installation process, sheathing boards are mounted on top of the film, and they partially cover the film. Thus, it is impossible to apply markers in advance in a place that will be guaranteed to be in the sun and not covered by the shadow of the sheathing.

Also, markers applied in advance may end up in a place inaccessible to observation when installing the film on the roof.

In addition, construction films have different surfaces, from smooth polyethylene to rough spunbond. The same paint will adhere and absorb into different materials differently. Accordingly, you will burn out differently. That is, for each type of film it will be necessary to use a separate ink, which is inconvenient for production, since it requires constant changing of ink in the printer, which will lead to constant stoppages of the production line, slowing down the production process, loss of labor productivity and increased costs.

Therefore, the described indicator is made in the form of a separate fragment and is attached by the builder in a place convenient for observation, not obscured by the shadow of trees or building structures. In addition, such an indicator is universal, suitable for any type of film.

Two types of indicators were tested. One is based on polyester, the second is based on polypropylene. Tests were carried out both in a climate chamber and on an outdoor test site at the plant. The task was to select a color applied to a surface such that fading would occur synchronously with the destruction of the film and at the same time, the surface on which the color was applied would not be destroyed under the influence of UV radiation. Polymerized oil-free toner Simitry HD E, used by printing houses, can be used as an indicator paint.

Construction films are tested according to the methodology described in GOST 32317-2012. According to GOST R 58913-2020, the recommended total duration of UV radiation for rolled water and windproof materials is 336 hours, which corresponds to a UV radiation dose of 55 M J/m ² . Tests carried out by the Federal State Budgetary Institution of Science Federal Research Center for Chemical Physics named after. N.N. Semenov of the Russian Academy of Sciences (FRC KhF RAS), showed that the strength of building films when irradiated with ultraviolet radiation initially decreases with a gradually increasing rate. The test results are presented in Table. 1. A graph of changes in breaking load during irradiation of gray nonwoven material is shown in Fig. 1.

As the table shows, a significant reduction in breaking load is achieved after 350 hours, which is close to the value established by GOST.

Both polyester and polypropylene based indicators were placed in a climate chamber for 336 hours. Samples of bright red, black, green, blue and yellow colors were taken for testing. The challenge was to find a color that would fade noticeably (but not completely) after 336 hours of UV exposure. After 336 hours, only the yellow indicator had faded such that the loss of color was noticeable. That is, from bright yellow it became pale yellow. The remaining colors either completely lost their color or did not fade enough to be noticeable to the eye.

Yellow is one of the most fadeable colors. This is due to the fact that yellow absorbs ultraviolet radiation more strongly. At the same time, there are colors, such as red and its shades, that fade more than yellow. The burnout of an indicator with such colors will occur faster than the process of film destruction.

During the experiment, the polyester-based indicator was preserved, but the polypropylene-based indicator was destroyed by UV rays.

After reading the results of 336 hours of irradiation, we continued to monitor the indicators in the chamber. After receiving 400 hours of UV irradiation, the polyester yellow indicator completely lost its color and turned white. At the same dose of UV irradiation, films lose more than 40% of their strength and become unsuitable for further use.

Thus, it was experimentally established that yellow polyester-based toner loses color after 336 hours of UV irradiation, turning from bright yellow to pale yellow, and that the same number of hours of UV irradiation is the maximum permissible dose for construction films.

When irradiated for more than 400 hours, the indicator completely loses color, and construction films lose the necessary strength, begin to deteriorate and require replacement.

To confirm the laboratory results, a test was conducted at an outdoor test site. Indicators were attached to films and weekly observations were made. Yellow indicators were tested and showed positive results in laboratory tests. The tests were carried out in June in central Russia. After a certain number of days, during which there were 336 hours of sunshine, the bright yellow polyester indicator turned pale yellow. The yellow polypropylene indicator has broken down. Thus, field tests confirmed laboratory tests.

The desired result was shown by an indicator made of polyester film, on one side of which yellow paint was applied, and on the other - an adhesive layer covered with a removable protective material, namely, craft paper.

The indicator is fixed using a construction stapler on the film itself or on the lathing installed on the building film, or other building structure located in close proximity to the film, in a place convenient for observation that does not interfere with UV irradiation. To more securely attach the indicator to the surface of the film, it can be equipped with an adhesive layer covered with removable protective material, such as craft paper. Before attaching the indicator, the protective material is removed, the indicator is glued to the place of attachment, after which it can be additionally secured using a construction stapler.

The indicator is included in each roll of film.

A QR code is placed on the indicator itself or on the label of the film roll, which directs you to an Internet site where you can compare the color of the indicator with a three-color scale. The bright yellow color indicates that the film has not yet been exposed to UV irradiation. Pale yellow indicates that the film has received the maximum permissible dose of UV radiation and must be urgently covered with roofing or facade material. White color means that the film has received such a dose of UV radiation that it will not perform its functions and requires replacement.

Thus, the described indicator makes it possible to obtain reliable information about the loss of strength of a building film already laid on a building structure and exposed for a long time to ultraviolet radiation before it is covered with an external building structure, for example, roofing or facade materials.

Claims (5)

1. An ultraviolet radiation indicator designed to determine the degree of loss of strength of building films, made in the form of a fragment of material with a color layer applied to its surface, the fragment being made of a polyester-based material, the outer surface of which has yellow paint applied. 2. The indicator according to claim 1, characterized in that the side of the fragment on which paint is not applied is made of adhesive, covered with a removable protective material. 3. The indicator according to claim 2, characterized in that the protective material is craft paper. 4. The indicator according to claim 1, characterized in that polymerized Simitry HD E toner is used as paint. 5. The indicator according to claim 1, characterized in that a QR code is applied to its outer surface.