CZ121294A3 - Multilayer glass-reinforced plastic with enhanced resistance against peeling and penetration of very quick projectiles - Google Patents

Abstract

The multi-layered glass laminate comprises from three to seven plies of glass (10, 12, 14) each ply having a thickness from 3.175 to 6.35 mm, with layers of plasticised polyvinyl butyral consisting of an adhesive energy absorbing layer (22) and a dimensionally stable polyester film (24) is permanently bonded to an outer layer of one of the piles of glass (14). The composite has a thickness of from about 0.762 to 0.381 mm and the adhesive layer has a thickness from about 0.381 to 1.524 mm and is made of a plasticised polyvinyl butyral. The polyester film is coated with an abrasion resistant coating.

Description

Multi-layer fiberglass with improved resistance to peeling and penetration of high-speed projectiles

Technical field

The invention relates to a multi-layered glass laminate with improved anti-bullet resistance by high-speed projectiles.

BACKGROUND OF THE INVENTION

Various types of laminated structures have been invented to protect people from flying shards and fragments of glazing materials that are released when high-speed projectiles hit the structure. According to U.S. Pat. No. 3,656,336, thick layers of amorphous polyamide are introduced into the sandwich structure of a silicate glass. U.S. Pat. No. 2,886,221 discloses a structure in which the polyraethyl methacrylate layers are laminated with polyvinyl 1 butyl and covered with a layer of polyamide, polyester or regenerated cellulose sheet. According to U.S. Pat. No. 4,130,684, it is used as a shock absorbing section in the structure of several layers of glass and polyvinyl butyral in combination with a plastic interlayer.

The peeling problem of a wear resistant layer applied to a laminate using polycarbonate layers is described in U.S. Patent No. 4,812,359 and solved by applying a thin polycarbonate layer having a wear resistant self-healing coating. A similar laminate that includes an inner flexible expansion core with a thin, polycarbonate layer coated with a wear resistant material that can be replaced is disclosed in U.S. Patent No. 4,879,183. British Patent No. 828381 discloses a five-layer laminate consisting of two layers of glass, two layers of polyvinyl butyrate and a central layer of polyethylene terephthalate. British Patent Application No. 2 156736A discloses an impact resistant laminate consisting of a plurality of layers of glass which are laminated together with a backing polycarbonate layer and resist peeling.

The problem with most bullet-proof structures is that their thickness exceeds the possibilities for common glazing purposes. Some structures effectively prevent peeling but do not stop projectile penetration of the laminate. Most structures are based on the insertion of different materials into the laminate structure. This complicates production and increases costs since different materials require different lamination techniques

According to the invention, a multilayer glass laminate having improved peel and penetration resistance of high-speed projectiles consists of at least three layers of glass with embedded layers of plasticized polyvinyl butyral, the laminate having a permanently attached outer layer of a thin composite consisting of an adhesive layer and a dimensionally stable, chemically resistant polyester film, the composite having a thickness not exceeding 2 mm and the polyester film having a thickness of about 0.762 to 0.381 mm.

The invention therefore relates to glass laminates with improved resistance to penetration of high speed projectiles. In particular, it relates to relatively thin glass laminates. which not only prevent peeling when cutting small and medium caliber bullets, but stop the penetration of laminates by bullets or other small high-speed projectiles.

Surprisingly, it has been found that the permanent bonding of very thin composites consisting of an adhesive layer and a dimensionally stable polyester film with multiple layers of glass with incorporated layers of plasticized polyvinyl butyral provides a substantially reduced thickness glass laminate capable of withstanding the penetration of high speed projectiles. if at all, by peeling from the inner back wall of the laminate.

The invention is therefore a laminated material to which an energy absorbing thin plastic composite is permanently attached, consisting of an adhesive, energy absorbing layer, for example a polyvinyl butyral layer, and a solid, dimensionally stable, chemically resistant and abrasion resistant layer, for example a polyester film layer. coated with a polysiloxane or other abrasion resistant coating. Thin plastic top of the glass laminate, on which the composite prevents peeling from the layer laminated. Surprisingly, other non-thin coraposite found that, in addition to preventing peeling, the composite increases integrity and penetration resistance of the structures on which it is superimposed when bullets or other projectiles fall on the opposite side. By retaining the surface glass and holding the structure together and with fully understood mechanisms, such a structure substantially improves the penetration resistance to an extent that such a thin composite could not have been expected.

According to the invention, a multilayer glass laminate consisting of at least three layers of glass is prepared by interleaving the layers of glass with the layers of plasticized polyvinyl butyral. The glass layers should have a thickness of approximately 3.175 to 6.35 mm and the polyvinylbutyral layer a thickness of 0.381 to 1.524 mm. A thin composite layer consisting of an adhesive layer of 0.381 to 1.524 mm thick polyvinyl lbutyral and a polyester film of 0.762 to 0.381 mm thick is permanently attached to the outer glass layer. The total thickness of the composite does not exceed approximately 2 mm. The present invention provides peel and penetration resistant structures with an overall thickness reduction of 20 percent or more compared to known glass laminates used for bulletproof glazing. Preferably, three to seven layers of glass are used, joined together by adhesive layers of polyvinylbutyral. It will be appreciated that the relative thickness and number of glass layers in the structure of the invention is determined by the level of handling, i.e. the size and speed of the projected projectiles.

Particularly preferred is the type of U.S. Pat. No. 4,229,272 to Moynihan, commercially available as Butacite® from E.I. Du Pont de Nemours and Company. Other known glass laminate adhesives such as polyurethane may also be used. The type of polyester film may be a film according to U.S. Pat. No. 4,072,779 <Knov>, which may be coated according to the specification with a wear-resistant material. The glass can be selected according to ASTM specifications Designation C 1172-91. The glass may be tempered or annealed. Tempered glass is usually preferred.

The invention is explained in more detail by the following description with the accompanying drawings.

1 and 2 are cross-sectional views of the edge of the bulletproof laminate

The overlap in the drawings of the 'transparent' laminate in Figure 1 consists of three layers of glass

10, 12 and 14. The glass layer 10 is positioned with its surface 11 in the direction from which a possible projectile is expected. like a bullet. The layers 10, 12 and 14 are joined to one another by interlayers of polyvinylbutyral having a thickness of 0.381 to 1.528 mm. A polyethylene terephthalate film having a thickness of 0.0762 to 0.381 mra is deposited on the surface of the vitreous layer 14 by an intermediate layer of polyvinylbutyral.

In Fig. 2, the laminate of Fig. 1 carrying a wear-resistant coating 26 adhering to the outer surface of the polyethylene terephthalate film 24. The coating 26 may be a silanol having a thickness of 1 to 20 microns of the type of U.S. Pat. No. 4,46943 and No. 4,173,715.

The laminated structures of the present invention can be prepared by known laminating methods. A polyvinylbutyral film is sandwiched between the glass layers 10, 12 and 14. Then, a composite of polyethylene terephthalate film as a polyester film 24 and a polyvinylbutyral film as an adhesive layer 22 are applied to the back of the glass layer 14. the assembly is covered with a cover sheet, the assembly is trimmed on the eyelets and placed in an airtight bag and evacuated. The evacuated assembly is then placed in an autoclave where the bag is kept under reduced pressure.

The invention is further illustrated by the following examples.

Laminated glass panels are prepared by interleaving 0.762 mm polyvinyl butyral layers between 304.8 mm square glass sheets with a nominal thickness of 2.54 mm. The selected panels comprise a composite attached to the outer layer of one of the glass panes consisting of a Butacit® layer, the polyvinylbutaryl layer having a thickness of 0.381 mm and the polyester film having a thickness of

0.178 min. On the center of each panel, 2 shot of 0.38 rifle from 4.572 m distance is fired in January. Weight in grams is used to measure the peeled glass from the back of the laminate. Peeled glass labeled is not measured, but the required glass labeled “+ · ►” weighs 10 labeled glass weighs less than about 0 the following table I. Table I

Standard glass laminate for about 50 to 100 grams, peeling 15 grams and peeled glass 2 g.

Composite with 1 m or more

Number T1oušťka Penetration Odloupnutí layers (mm) <g> 4 4 4 4 11.94 Yes 85.1 5 15.24 No 10.3 5 15.24 No + - * 5 15.24 Yes 5 15.00 No 4-4-4- 5 15.00 Yes 4-4 - »- 6 18.30 No 13.7 6 18.00 No ++ · 7 21.34 No 9.5 7 21.34 No 0.0 7 21.84 No 4-4 · 8 24.38 No 0.29 9 29.94 No 4-

Thickness Průn i k Odloupnutí Cmm) <g> 12.45 No 0.0 12.95 No 0.0 12.45 No 0.0 12.45 Yes +++ 15.75 No 0.0 15.49 No 0.0 15.49 No 0.0 15.75 No 0.0

27,94 no

Results similar to those obtained with four layers of glass plus composite, as seen above, are achieved by using three layers of glass plus composite with a total thickness of 12.5 mm.

In Table II, the results of Table I are condensed and rearranged to show percent penetration depending on sample design, thickness, and ratio of penetration to number of samples tested for each type. When focused on samples with four layers of glass, the standard laminate penetrates, while a sample having the same number of layers plus the composite cover is penetrated in 25% of cases. In tests where the composite is not penetrated, no blunting occurs. This improvement results from the addition of poly (ethylene terephthalate) and a polyvinyl butyral adhesive film only 0.559 mm thick compared to a glass laminate thickness of about 12.7 mm (an increase in thickness of 6.4. The same image is evident in samples containing 5 layers of glass where the number of data is greater. In this case, the bonding of the composite reduces the penetration frequency from 40 to 0% with a thickness increase of only 3.3. When 5 layers of a standard glass laminate are compared, it can be seen that greater protection of 4 layers of the same glass thickness with the composite glass laminate Even increasing the thickness of the laminate to 15.24 mm (5 layers of laminated glass) will reduce the actual penetration to only 40% (27.7 in the case of an increase in thickness).

Table II

Standard fiberglass Composite fiberglass

Number Thickness Penetration Ratio Odloup- Thickness Penetration Ratio Odloup- layers (mm) forces Cg) (mra) forces Cg) 4 11.94 100¾ 1/1 85.1 12.7 25¾ 1/4 0.0 5 15.24 40¾ 2/5 10.3 15.62 0¾ 0/4 0.0 6 18.30 0¾ 0/2 13.7 7 21.59 0¾ 0/3 9.5 β 24.38 0¾ 0/1 0.2 9 27.94 0¾ 0/1 4- 11 35.56 0¾ 0/1 0.0 Industrial utilization

Multilayer glass laminate with improved resistance to high-speed peeling and penetration consists of at least three layers of glass interleaved with layers of softened polyvinyl lbutyral and a thin composite consisting of an energy-absorbing adhesive layer and a dimensionally stable polyester film permanently adhered to the external glass .

Claims (3)

1. A multilayer fiberglass with improved resistance to peeling and penetration of high-speed projectiles, characterized by layers having a glass thickness of three to seven (10,12,14) having a thickness of 3,175 to 6,35 mm, with layers ¢ 16,18,20) plasticized polyvinyl-butyral resin ^ in between them, the laminate having a permanently bonded thin composite to the outer surface of one glass layer, consisting of an adhesive layer ¢ 22) absorbing an energy-resistant polyester film and dimensionally stable, chemically ¢ 24) wherein the thickness of the composite does not exceed 2 mm and the polyester film has a thickness of 0.762 to 0.381 mm and an adhesive layer of ivavurn. has a thickness of 0.381 to 1.524 mm. Laminate according to claim 1, characterized in that the polyvinyl 1 butyral is a plasticized layer. Laminate according to claim 1, characterized in that the polyester film is provided with a wear resistant coating. t GIANT. 1