RU2184093C2 - Multilayer glass polymeric composition - Google Patents

Abstract

FIELD: polymers. SUBSTANCE: multilayer glass polymeric composition consists of glass-block having glass layers of different thickness and combined by glue interlayers and at least two polymeric films combined with a glass layer of the smallest thickness. Glue interlayers have a wave resistance maximally closed to a wave resistance of glass layers. Value of a wave resistance of glue interlayers is (11-13) x 10⁵ kg/(m² x s) and those of glass layers (30-50) x 10⁵ kg/(m² x s). Each following glass layer has a thickness less of a former layer. The first and second layers of glass can be made with a possibility of predestroying. Invention can be used for protection of compartments, cars from the nonsanctioned penetration and from small arms. EFFECT: decreased thickness of glass package, enhanced resistance against gun rupture and double glass pane, simplified method of glass package making. 3 cl, 1 dwg

Description

 The invention relates to the construction, glass industry and is intended for protective purposes as bulletproof glass.

 A multilayer fiberglass composition is known (see French application 2574779, class C 03 C 27/12 of 1986), containing a glass packet of glass layers interconnected by adhesive layers and connected to the glass packet from the side of the glass layer with a lesser thickness of polymer layers material.

 A disadvantage of the known composition is the low-tech assembly of the glass unit and the large thickness of the entire composition.

 Known composition according to PCT patent NWO 93/1097, class. 32 B 17/10 of 06/10/93, containing a glass block of at least three layers of glass, interconnected by adhesive layers, and at least two combined polymer films attached to the glass block by means of an adhesive layer.

 The disadvantage of this composition is the low efficiency of the glass unit used, its large thickness.

 Closest to the proposed multilayer glass-polymer composition is a multilayer composition containing a glass block of at least three layers of glass, each of which has a thickness less than the previous one, interconnected by adhesive layers, and several polymer films attached to the glass layer of the smallest thickness by means of an adhesive layer (FR 2597857, class C 03 C 27/12, 1986).

 The technical problem to which the invention is directed is to reduce the double-glazed window, increase the resistance to bullet breakdown and spall destruction, increase the manufacturability of the assembly.

 This technical problem is solved due to the fact that in a multilayer fiberglass composition containing a glass block of at least three glass layers interconnected by adhesive layers, and at least two polymer films attached to each other, attached to the glass block by an adhesive layer, the thickness of the glass layers in the glass block are not equal to each other and each subsequent layer of glass has a thickness less than the thickness of the previous layer, and polymer films are attached to a layer of glass having a smaller thickness Well, and the adhesive layers have a wave impedance as close as possible to the wave impedance of the glass layers. The decrease in the thickness of the glass layer from layer to layer can be 25%, polymer films can have equal wave impedances, and the maximum thickness of the adhesive layer is 0.8 mm.

The first layer of glass block glass can be configured to pre-fracture upon reaching a load of P ₁ , the second layer of glass glass block can be configured to pre-fracture when a load is reached P ₂ <P ₁ , and the third layer of glass in the glass block can be configured to prevent formation pre-destruction upon reaching its ultimate load P> P ₁ .

 The invention is illustrated in the drawing.

A multilayer fiberglass composition includes:
1) the upper first glass layer;
2) the middle glass layer;
3) the lower glass layer;
4) a film polymer layer;
5) a film polymer layer;
6) an adhesive layer;
7) adhesive layer.

Bulletproof glass-polymer composition that can withstand three times the impact of the TT pistol without spalling phenomena on the back of the package with the structure according to the drawing may consist of the following layers:
- layer 1: glass of the Salavat factory, thickness 5 mm;
- layer 2: glass of the Lisichansk plant, thickness 4 mm;
- layer 3: Bor glass, thickness 3 mm.

- adhesive layers (items 6 and 7): photopolymerizable acrylate-based adhesive composition, type FPK-P1 (TU 2435-001-22890649-94), thickness 0.8 mm;
- polymer films (items 4 and 5): quantity - 2 pcs., type - Solargard polyester, thickness 14 mil (0.355 mm).

 The total thickness of the composition is 14.3 mm.

The composition, the conversion of curing, the degree of technological compaction of the adhesive layers are assigned from the condition of the optimal (maximum) approximation of their specific wave resistance (Z _s ) to the specific wave resistance of the glass layers. The parameter Z _s is understood as the value determined by the ratio:
Z _s = Z _a • S, (Pa • s / m),
where Z _a - wave impedance;
S is the cross-sectional area of the elastic wave propagation channel with the pressure level at the front P and with the space velocity q.

Here Z _a is the proportionality coefficient in the equality:
P = Z _a • q,
Z _a (Pa • s / m ³ ); q (m ³ / s).

For example, we compare the properties of glass layers and adhesive layers according to the parameters: Z _s — transverse specific wave resistance; Z _l - longitudinal specific wave impedance; V _s is the transverse velocity of the elastic wave; V _l is the longitudinal velocity of the elastic wave.

For the variants of the glasses used, we have ranges of variation of these parameters:
V _l = 350-6000 m / s; V _s = 1250-3800 m / s;
Z _l = (60-130) • 10 ⁵ kg / (m • s); Z _s = (20-80) • 10 ⁵ kg / (m • s).

For variants of methyl methacrylate adhesive compositions plasticized with dibutyl phthalate, these parameters vary within:
V _l = 1500-3200 m / s; V _s = 1200-1500 m / s;
Z _l = (15-35) • 10 ⁵ kg / (m • s); Z _s = (8-13) • 10 ⁵ kg / (m • s).

The functionally assigned levels of the last parameters are limited by the ranges:
V _l = 2800-3200 m / s; V _s = 1400-1500 m / s;
Z _l = (28-30) • 10 ⁵ kg / (m ² • s);
Z _s = (11-13) • 10 ⁵ kg / (m ² • s).

 Multilayer systems, known as analogues of the proposed system, have a minimum thickness of 15-16 mm, are prone to spall fracture after the first bullet of significantly lower power (for example, a 0.38 caliber pistol).

 In addition, well-known multilayer systems are manufactured using expensive and time-consuming autoclave technology. The proposed laminated glass is made by the technology of photopolymerization of blanks aligned along the perimeter without the use of technological high pressure.

 The considered composition (multilayer system) has similar characteristics of resistance to indenter impact, both in the flat version and in the molded (curved) version.

As noted above, the general systematic combination of glass layers of different thicknesses, separated by polymer adhesive layers and closed by a multilayer film system, is shown in the drawing. The concentrated pulsed action P (t) in this system causes a complex picture of stress and strain waves due to the combination of media with sharply different wave impedances Z _s and the multiplicity of the interfaces between these media.

 The system consists of the thickest glass layer 1, an intermediate adhesive layer 7, a glass layer with a reduced thickness 2, an intermediate adhesive layer 6, the thinnest glass layer 3, a film system of two elements 4 and 5.

Factors that primarily determine the consistency of wave processes in the block under consideration include:
1) physico-chemical characteristics of the combined glass and polymer layers;
2) the ratio of the thicknesses of the combined layers of glass;
3) uniformity and thickness of the closing film system (4 and 5);
4) the boundary relations of wave impedances Z _{s of} successively combined glass and polymer layers. Moreover, the values of their wave impedances should be as close as possible to each other.

 When the value of the layers 1, 2, 3, data are used on the dynamic characteristics of real glass components obtained by a special method of impact testing. Tests of samples of various glasses under load conditions approximately adequate to real operational loads showed that glasses of various manufacturers have significantly different physicochemical characteristics of ultimate destructive states. First of all, the fact that some initial (raw) glass components are characterized by the phenomenon of prefracture, deserves serious attention, the development of microcracking at the initial stages of the development of the impulse load and long before reaching the ultimate load of the destruction of the sample as a whole. Samples of other glasses did not reveal the phenomenon of prefracture up to the level of ultimate load.

Glasses with pre-cracking were used in the system under consideration for layers 1 and 2. Glasses of this type have the property of relative reduction of the stress level at the front of the stress wave excited by the load P (t). Let us qualitatively explain this by the relation establishing the relation between the level of stresses at the leading edge of the wave and the parameters of the medium loaded by the wave method:
σ $\genfrac{}{}{0ex}{}{\text{2}}{\text{i}}$ = T $\genfrac{}{}{0ex}{}{\text{2}}{\text{i}}$ + 3 • (ρ • v ² ) -2 • (ρ • v ² ) ² ,
where T _i is the intensity of kinetic stresses in the considered region of the medium;
ρ is the density of the medium;
v is the mass velocity of the particles of the medium.

Upon reaching T _i the stress level of the initial processes of microcracking, the initial continuity of the medium is violated, the average density of the medium ρ changes abruptly. Moreover, multiple microcracking of the indenter penetration zone as a whole reduces the continuity of the medium and, therefore, decreases the density ρ in the kinetic regions of the formation of the stress wave. In accordance with the above relation, a certain underestimation of the stress level at the leading wave front σ _i occurs.
An underestimated stress level σ _i also causes reduced T _i in the second glass layer along the component of the direct expansion wave. Glass of the second layer also has the property of stress reduction, and at an even lower level of initial reinforcing pre-fracture. This quality of layers 1 and 2 contributes to some unloading of the thinnest, third layer of glass 3.

 The considered phenomenon of initial prefractures has a necessary beneficial effect on the functioning of the entire package as a whole, provided that conditions are created for the most rapid use of waves of kinetic stresses in all the underlying layers of glass. It has been established that these conditions are partially realized with a successive decrease in the thickness of the glass layers in the direction from the indenter penetration zone.

The trailing multilayer film system on the back of the glass block has a significant effect on the reflective conversion of the direct expansion wave excited on the lower surface of the glass block. In the absence of a film system, an intense wave of the opposite sign (tension) is excited, which is the generator of spallation processes in the glass block. Moreover, the intensity of the reflected wave can be so high that even the non-manifesting pre-fracture third layer of the glass block will not successfully resist spallation processes. The introduction of the film eliminates the sharp difference in the wave impedances of the glass and the air. In particular, this leads to some underestimation of the intensity of the reflected wave of the opposite sign. The degree of reduction of the reflected wave increases with an increase in the number of combined polymer films. In the given example of a specific system, the polymer closing layer of two successively glued films turned out to be effective. However, it should be borne in mind that the combined films must have the same wave impedance, i.e., a composite polymer block must be made of the same films. If this block is assembled from films with different Z _s , then testing shows that the layering of the multilayer polymer block after the first act of indenter exposure is most likely to occur. That is, the system works out in a reliable protective mode only once. Secondary loading of the same system will cause either its direct breakdown, or intense spall damage.

According to claim 4, we note that the optimal ratio of wave impedances Z _{s of} glass and intermediate adhesive layers is important. Each intermediate adhesive layer introduces its perturbations at the front of the direct expansion wave. These disturbances are greater, the larger the boundary inconsistencies in the parameters Z _s . Too sharp a difference in the levels of these parameters in the layers being combined can lead to a significant localization of the impact energy in the crater formation zone and to an accelerated transition of the multilayer system to the stage of sharply localized fracture.

An optimally selected adhesive layer at the level of Z _s must also have an optimal thickness, since approbations of various adhesive fragments according to the method of testing glass blocks in accordance with the technique of controlling wave processes showed that the thickness of adhesive layers significantly affects the development of wave processes of entrainment of impact energy from the crater formation zone. Tests according to the method clearly indicate that there is a certain critical thickness of the adhesive layer, above which the efficiency of the wave processes of energy loss in individual glass layers drops sharply.

Claims (3)

1. A multilayer glass-polymer composition containing a glass block of at least three glass layers, each of which has a thickness less than the previous one, interconnected by adhesive layers, and at least two polymer films combined with each other, attached to the glass layer of the smallest thickness by means of an adhesive layer , characterized in that the adhesive layers have a wave resistance as close as possible to the wave resistance of the glass layers: wave resistance of the adhesive layers (11-13) • 10 ⁵ kg / (m ² • s) and glass layers (30-50) • 10 ⁵ kg / (m ² • s), the first layer of glass block glass being configured to pre-fracture upon reaching a load of P ₁ , the second layer of glass glass block is configured to pre-fracture upon reaching a load of P ₂ <P ₁ , and the third layer of glass in the glass block is made with the possibility of eliminating the formation of pre-fracture upon reaching its maximum load P> P ₁ .  2. The composition according to any one of paragraphs. 1-3, characterized in that each subsequent layer of glass glass has a thickness of 25% less than the thickness of the previous layer.  3. The composition according to any one of paragraphs. 1-4, characterized in that the maximum thickness of the adhesive layer is equal to 0.8 mm