The practice of using flat architectural glass as a building material is calculated for decades. During this time, manufacturers have made significant progress in manufacturing and processing technology, bringing its main characteristics and properties to near perfection. In the development of glass, nanotechnologies are increasingly showing themselves , which allow to give it specific, extraordinary operational and aesthetic qualities, thereby opening new perspectives for architects and designers.

For the sake of fairness, we note that the most significant improvements in all the properties and capabilities of glass as a building material were discovered thanks to the appearance of multilayer safe glass products. All the main valuable operational and technological properties of such glass are achieved due to the use of the ” sandwich ” principle, i.e. formation of a layered heterogeneous structure of a composite with an intermediate polymer layer. The significance and implications of these developments are still difficult to assess.

Glass makes an attempt to perform a revolutionary “feat” and become one with the main building materials: steel and reinforced concrete.

Unfortunately, until now, many issues of improving technologies and equipment for creating multilayer glass (equipment for triplex) remain outside the attention of researchers, which seriously inhibits the practical development of the entire spectrum of safety glass possibilities. Most of the new properties remain hidden and require serious theoretical and experimental studies. These include: a detailed study of the mechanism of formation and development of technologies for obtaining multilayer glass based on innovative polymer materials, which are characterized by higher strength properties compared to existing ones, research into the characteristics and application possibilities of hybrid structures based on new composite components.

A combination of fragile glass and plastic materials (for example: polycarbonate-glass sandwich , glass-acrylic glass block and many others) will optimize the functionality of multilayer safety glass. There is no doubt that the development of research in these directions will stimulate the further improvement of already existing and the development of new approaches in the design and creation of devices for the industrial production of multilayer glass.

And so, regardless of the differences in the scientific and technical interpretation of the terms “multilayer glass”, “laminated glass”, “triplex glass”, let’s stop at the generally accepted definition:

Glass lamination is a method of creating a stable combination of flat or curved glasses glued together over the entire surface using liquid or film polymer materials.

Currently, in the world, two technologies are used for the production of all types of multilayer glass: this is the liquid casting technology, based on the use of plasticized resins as an intermediate layer (casting) and the technology when, at high temperatures and pressure, a ready-made glass is used as a binder between the layers of glass polymer film.

Casting technology, due to technological and operational limitations, occupies certain rather narrow niches in the general segment of safety glass production.

In turn, film technology is divided into two groups: autoclaved and non-autoclaved. Both technologies are based on the same physical principles. The main differences are in the technical implementation and sequence of technological operations.

Since today, when choosing industrial equipment, the economic factor is not the last, the attention of manufacturers of flat multilayer glass has recently been directed to autoclave-free film technology. In addition, the appearance of new films for non-autoclaved triplex opens up wide possibilities of its use for architectural purposes, especially for tempered and painted glass.

Unfortunately, a serious drawback of both technologies is a very high percentage of defects, which can be up to 10-15% of the output of products.

The main reason for the unsatisfactory quality of such products is usually the presence of ” casts ” and “bubbles” at the glass-polymer interface, which is associated with local differences in the values of adhesive strength on the surface of glass, especially large formats.

Therefore, the most important task in the production of multilayer glass is the problem of uniformity and increase of adhesive strength over the entire contact surface of polymeric materials and glass. This task can be called decisive both in the design of the equipment and in the optimization of the technological processes of the production of safety laminated glass.

Undoubtedly, first of all, the adhesive properties depend on the chemical nature of the polymer materials that make up the multilayer glass composition (an independent section of polymer chemistry). In addition, it is important, from the point of view of the formation of an adhesive contact, to strictly observe the technological regulations of the preparatory processes (washing and drying of glass blanks and film, assembly and stacking of the package, preliminary vacuuming, etc.). However, as theory and practice show, the main reason for marriage is initially laid in the heat treatment cycle.

The reason for this is the specific thermophysical properties of glass, which leads to uneven heating of the multilayer composite on the plane and thickness, this is especially important when it comes to not the simplest combination of glass-polymer-glass (the so-called triplex), but multilayer glass of the polyplex type . Theoretical and applied works in the field of glass heating are reflected in a number of monographs and reviews published over the past 10-15 years. However, in them, the main attention is paid to the optimization of heat-technological operations during tempering, heat strengthening, painting of flat glass.

It is generally accepted that the creation of safety glass manufacturing equipment capable of providing the most suitable heating regimes for a multilayer composition (especially of large sizes) is a complex technological problem.

In fact, it can already be noted that some previously common types and methods of heating glass in lamination furnaces, due to limited operational characteristics, are losing their positions, yielding to more progressive IR heating.

Due to the possibility of creating a significant increase in heat flow density on selected areas of the surface of the irradiated object, the availability of controlling the speed of heat supply, penetration deep into the material, the use of IR radiation can intensify many technological processes of heat treatment. Unfortunately, at present, a restraining factor on the way to the development and implementation of this type of heating in lamination furnaces is, unlike standard convection systems, the complete lack of practical results and basic theoretical provisions, as well as a systematized and convenient method of engineering calculation for use in practice.

Thus, there are objective prerequisites for solving the following scientific and technical task:

In order to increase the efficiency of the production of multilayer building glass, develop a methodology, a method of adaptation and support of a set of measures and operating modes of lamination devices, which provide optimal conditions for the formation of a uniform, stable adhesive contact of glass and intermediate polymer over the entire surface.


  • glass-polymer interface under the conditions of adhesive contact formation (that is, at temperatures above 100 ° C);
  • to assess the influence on the temperature state of glass of such factors as spatial heterogeneity of falling radiation flows, temperature dependence of thermophysical and optical properties in the spectrum range of 0.8-2.0 μm, volume absorption of radiation by glass;
  • to develop a method of control and management of temperature fields in multilayer glass products under conditions of complex combined radiation-conductive heat exchange. At the same time, it is important to have an algorithm for forecasting temperature fields not only for surface zones, but to estimate the change in the temperature field and the magnitude of temperature gradients throughout the thickness of the glass product;
  • to ensure fast and uniform heating of multilayer glass by thickness, it is necessary to find technological and constructive solutions of effective zones of radiation influence on products, which allow to ensure high productivity of the process in combination with a significant reduction in time and energy consumption;
  • to synthesize the law of optimal speed control of heating of multilayer glass;
  • to develop means of stabilization of mode parameters and control of dynamic modes of lamination.

The task of optimizing heat engineering operations in the production of laminated glass has been considered several times before, its solutions in various settings made it possible to develop a number of practical recommendations aimed at improving the characteristics of the heat treatment process.

However, a comprehensive methodology with a single criterion for working modes has not yet been developed. Summarizing the results of practical operation of lamination furnaces of domestic and foreign design shows that when transferring installations from one type of glass products to another or changing the type of intermediate polymer film, a serious adjustment of operating modes is required. Operators of lamination installations have to either conduct optimization experimentally, or rely on technological regimes and operations recommended by film manufacturers (which are not always of a generalized nature, but are mostly aimed at compensating for the technological shortcomings of the material and are not tied to the principle and hardware implementations of a specific installation) .

Naturally, at the same time, the flexibility of production is significantly reduced, the possibility of marriage is not excluded. In addition, heat treatment modes chosen based on practical experience often turn out to be not the most effective. And as a result, all this has a negative effect on the value and consumer properties of its products. Equipment developers need a specific description of the conditions and physical processes of the formation of adhesive bonds, taking into account the specifics of each material. An analogy can be drawn – powder paints, like lamination films, are also divided into two main classes: thermoset and thermoplastic.

With paints, everything is clear: to form a coating, you need either thermal exposure (for thermoset), or the temperature of heating the object, which is recommended (for thermoplastics). When laminating, we have a complex combination of glass-polymer-glass-film (for pressure, as a rule, a silicone membrane with a thickness of at least 4 mm) that is difficult in terms of heat exchange. Formally, in a super simplified form, the task of lamination is reduced to the gluing procedure: by heating the adhesive film, pressing and holding.

Since the analytical description of the process of heating multilayer glass under conditions of complex heat exchange is an extremely difficult task and can be solved only under the condition of a huge number of assumptions and simplifications, the results obtained by physical modeling can be of practical interest.

The basic construction concept, as well as the selection and justification of rational modes of IR power supply in lamination technology were studied and tested on a specially developed combined IR installation of an industrial type using low-inertia linear quartz IR sources. The general appearance of the installation is shown in the photo.

At the first stage of the design of the experimental installation in the order of trial experience (within the framework of serious simplifying assumptions and assumptions), we tried to analytically connect the task of radiant heat exchange with the layout of the entire installation, assuming a discrete arrangement of IR emitters taking into account their design, geometric dimensions and configuration reflect screens.


  • the periodic unevenness of the temperature distribution of the heating object in the direction of the chosen axis of the location of the sources depends on the distance between the emitters and the surface of the object and practically does not depend on the distance between the emitters and the reflecting surface;
  • unevenness is determined by the ratio of the distance between the emitters and the surface of the object to the step between the emitters, and when this parameter is equal to or slightly greater than unity, the unevenness of the temperature field is insignificant;
  • in the case of using the upper and lower heating sections, it is optimal to combine the IR generators into thermal blocks and their mutual cross-checkered arrangement in two planes relative to the irradiated surface.

The second important task is the optimization of the speed of dynamic modes of complex heating of a glass-polymer sandwich under given boundary conditions and limitations on the temperature gradient across the thickness of the multilayer glass, taking into account the spatial distribution of the temperature field of IR sources. The following contradictions that arise during the optimization of the dynamic modes of heating the composite structure have been revealed. On the one hand, it is necessary that the duration of heat treatment be minimal, and on the other hand, the temperature gradients must have a certain value, while the final value of the temperature of each intermediate polymer layer (in the case of polyplex type glass) must exactly correspond to the recommended temperature of polymer processing .

Rapid heating of glass (often implemented in lamination furnaces by increasing the power reserve) creates excessive temperature gradients both in terms of volume and thickness of the package, which can lead to uneven heating of the polymer and even to its boiling. Slow heating allows you to significantly reduce the gradients in the volume of the package, but at the same time, the heating time to the lamination temperature is significantly increased, which reduces the productivity of the installation, and at the same time, the
final temperature distribution over the thickness of the glass product is of great importance, since even a slight underheating of the polymer to the melting temperature can lead to before marriage in the form of “cloudiness”.

In this regard, the task of managing the dynamic mode of IR heating of the package can be formulated as follows:

With the given energy flux densities, the maximum permissible values ​​and the temperature gradient in the thickness of the package, it is necessary to find the law of managing the regimes of iR-saurses, at which the central convertes of the permanent polymer film in the composition of the magnify MELTING IN THE MINIMUM TIME.

It was hypothesized that one of the ways to solve this problem is the use of a pulsed method of IR heating of a multilayer composite based on flat glass and polymer materials.

The oscillating mode of IR power supply involves optimization detection of the effective pulse rate of the emitters (internal heat transfer) and development of recommendations for calculating the maximum duration of the oscillation cycle (external heat transfer ). This regime will not allow exceeding the maximum allowable temperature of heating the polymer.

In connection with the need to measure and regulate the temperature of the glass sandwich , an information-measuring system for controlling pulsed IR heating was developed, which allows maintaining the maximum and minimum temperature of the material.

Taking into account the obtained results of physical modeling, we manufactured industrial installations for the production of glass products that are laminated, based on the application of radiant heating and developed methods of volumetric equalization of the temperature field of the product, due to zonal control of local radiant flows of external IR radiation.

MODEL GLL – 4,1/2,5 IR


the GLL -4.1/2.5IR lamination equipment, good results were achieved both in terms of the quality of glass lamination with different types of films, and in terms of specific energy consumption. In this, a good repeatability of the quality of the original products was observed. It has been experimentally proven that it is possible to laminate products of different thicknesses in one furnace with IR radiation while maintaining adhesive , strength and optical characteristics.

In addition, the results obtained during the operation of the machine made it possible to make certain corrections in the theoretical understanding of the processes of formation and control of adhesive properties of polymers, as part of a complex glass-polymer sandwich . Approaches to the practical implementation of individual blocks and nodes were changed in order to increase the efficiency of machines of this class. First of all, this applies to systems for optimizing the oscillating mode of IR power delivery .

Summing up, it can be stated that for the first time, the possibility and perspective of using short-wave pulsed IR heating in lamination machines in the production of safety multilayer glass has been shown.


  • general issues of adhesive interactions of various intermediate materials at the glass-polymer interface;
  • development of a mathematical model and method of engineering and design calculation of an IR installation;
  • research of the optical and thermoradiation properties of the pressing material and their influence on the kinetics of IR heating of the composite (although this issue is more related to a particular case of the applied technology than to the general theory of glass lamination);
  • assessment of the effect of preparatory operations on the surface of glass and polymer before lamination on adhesive strength;
  • study of the influence of special coatings on the surface of glass on the processes of heat exchange by radiation in an IR installation, on the transfer of energy in the absorbing-reflecting components of the heat treatment object.

Continuation of work in this direction will probably make it possible to develop more correct practical recommendations and thereby make serious progress in the direction of reducing the percentage of marriage and improving the quality of the safety laminated glass produced.