SAFETY GLASS AND METHOD FOR OBTAINMENT

BACKGROUND OF THE INVENTION

[001] FIELD OF THE INVENTION

[002] This invention refers to a safety glass and its obtainment procedure. Although it may have diverse application fields, its development arises from the need for safety glasses of high resistance in order to increase the safety of vehicles' occupants.

[003] DESCRIPTION OF THE RELATED ART

[004] The current status of the technique involves diverse combinations of materials and procedures to obtain armored glasses. Common materials used are:

[005] a) Polyvinyl butyral films (herein after referred to as "PVB"). Example: PVB films manufactured by Kuraray Arg.

[006] b) PolyEthylene Terephthalate films (hereinafter referred to as "PET"), generally Crystallizable PolyEthylene Terephthalate because of its high transparency (hereinafter referred to as "C-PET"). Example: PET films manufactured by Kuraray Arg.

[007] c) PolyUrethane films (hereinafter referred to as "PU"). Example: PU films manufactured by Dayplas S.A.

[008] d) Safety films with adhesive, such as those manufactured by Llumar, 3M, Madico, Johnson & Johnson, Sunguard, etc.

[009] e) Safety films without adhesive, such as those also manufactured by Llumar, 3M, Sunguard, etc. or safety films with adhesive from which the adhesive is removed. [0010] f) Obviously, special glasses or original glasses used for this application.

[0011] Each of these materials have diverse densities and one or more layers may be used. The point is that the key to obtain positive and practical results for each need is based on the combination of films and especially on the procedure by which these films are combined with glasses. This is where this invention stands out and where one of the pillars which provide the basis for this patent application lies.

[0012] Furthermore, there are operating aspects such as a higher efficiency and flexibility of procedures, together with the impact of such procedures on the environment, which could not be solved to date.

[0013] In accordance with what has been analysed above, some antecedents for informational purposes follow:

[0014] a) European Patent No. EP1322467B1 "INTRUSION RESISTANT GLASS LAMINATE" granted on 11-28-2007. It consists of a laminated glass composed of: a first PBV film + a first PET film + a second PET film + a second PBV film, all of these inserted between two glasses. These films are placed between two glasses as usual.

[0015] Aside from the details of the procedure, in this case two PET films are placed between PBV films, all of which is placed between two glasses, that is to say, two glasses are needed.

[0016] b) US Patent No. 5,569,537 "Laminated glass with polyurethane resin layer and silane coupling agent layer" granted on 10-29-1996. This patent protects laminated glass with polyurethane films which requires an adhesive agent. It is based on the chemical aspects of the silane agent. [0017] c) US Patent No. 5,445,890 "Bullet resistant glass/glass, glass/plastic, and plastic/plastic laminate composites" granted on 08-29-1995. This patent protects a composite of laminated glass which comprises at least 2 glasses bonded by a layer of adhesive polyester. It may or may not include a "plastic" film between the two glasses, bonded by adhesive polyester.

[0018] d) US Patent No. 4,241,140 "Laminated safety glass with polyurethane film", granted on 12-23-1980. It specifically protects polyurethane film used for safety glasses.

[0019] e) US Patent No. 4,075,386 "Security film for shatterproofing windows" granted on 02- 21-1978. This patent refers to a method of applying films with adhesive and watery detergent. It comprises the basic concept of safety films.

[0020] f) PCT Patent Application WO2003006240 Al "Compositor interlayer for laminated glass" published on 01-23-2013. This application claims the joint use of PU and PVB without considering a key aspect of the procedure modified by this application.

[0021] i) US Patent No. 4,594,290 "Impact resistant laminate" granted on 06-10-1986. It refers to a laminate with high ballistic resistance. It uses glass, PU, PMMA and PC.

[0022] Although we have seen great progress in safety glasses during the last decades, a correct combination of films without adhesive which only requires a single glass, offering exceptional characteristics regarding resistance to impact, high transparency and low impact on the environment, could not be achieved yet. These are the key aspects of this invention. BRIEF SUMMARY OF THE INVENTION

[0023] One of the purposes of this invention is to obtain a safety glass which offers high resistance to impacts using a single glass.

[0024] Another purpose of this invention is to manufacture a safety glass reinforced on its interior as well as its exterior faces.

[0025] Another purpose of this invention is to create an innovative method for the obtainment of a reinforced safety glass which reduces substantially the impact on the environment.

[0026] Another purpose of this invention is to obtain a safety glass which, once broken, avoids the risk of cuts, lacerations or injuries of any kind.

[0027] Additionally, another purpose of this invention is to obtain a safety glass which offers a higher sound isolation inside vehicles.

[0028] Finally, another purpose of this invention is to obtain a safety glass which reduces the passage of UV rays to the inside of vehicles, reducing, as a result, the temperature inside them.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 schematically shows the components of a first exemplary embodiment of the safety glass.

[0030] Figure 2 shows a cut outline of the components of the first exemplary embodiment of the safety glass of this invention, including a polycarbonate film used as a bonding agent during the manufacturing process. Specifically, during the prelaminating process.

[0031] Figure 3 shows a cut outline of the components of a second exemplary embodiment of the reinforced safety glass of this present invention, including both polycarbonate films used during the assembling process. Specifically, during the prelaminating process.

DETAILED DESCRIPTION

[0032] The present invention comprising safety glass 1 and the procedure for its obtainment will now be described using figures 1 through 3.

[0033] High resistance safety glasses are used to provide higher safety inside the room surrounded at least partially by said glass. This invention has diverse application fields such as apertures for homes, surveillance booths and banks. However, its main application are vehicles of all kinds because it uses their original glasses, therefore eliminating the need for specific glasses. This application stands out from others which require the manufacturing of a new template glass during the manufacturing of the safety glass.

[0034] In order to obtain the safety glass of this present invention, films of diverse reinforcing

materials are used. Their special features offer higher resistance to the glass. During the manufacturing process, pressure and temperature are applied using autoclave in order to bond the reinforcing films to the original glass and between each other.

[0035] From the point of view of its construction, the safety glass is basically composed of the

original glass to be reinforced (with adhesive in its inner face), at least one PVB film and at least one C-PET film, in this same order.

[0036] An exemplary embodiment of this present invention, comprises at least one PVB film with a density of between 0.18 mm and 2 mm and a C-PET film with a density of between 0.18 mm and 2 mm.

[0037] In addition to the PVB and C-PET films, a safety film without adhesive may be applied on the exterior face of the original glass to be reinforced. Another alternative is to apply a safety film with adhesive, that is to say, a film including adhesive.

[0038] The density of the safety film (either with or without adhesive) is approximately between 40μιη and 400μιη. [0039] In another exemplary embodiment of the safety glass the exterior face of it is reinforced once the interior face is reinforced. In other words, at least one PVB film and one C-PET film are applied, in this same order, to the exterior face of the glass, without adhesives.

[0040] Having described the exemplary embodiments of this invention, the steps for the obtainment of the safety glass are as follows.

[0041] For the first exemplary embodiment:

[0042] a) thorough cleaning of the original glass;

[0043] b) ionize with ionizing gun at least one PVB film;

[0044] c) insert at least one PVB film on the interior face of the original glass;

[0045] d) ionize with ionizing gun at least one C-PET film;

[0046] e) place at least one C-PET film over at least one PVB film;

[0047] f) cut the excess of PVB and C-PET films by the edges;

[0048] g) place a cover of polycarbonate, generally with a density between 1.5 and 4 mm, over the last C-PET film;

[0049] h) place the product obtained from steps a) to g) inside a vacuum bag; [0050] i) vacuum the obtained product;

[0051] j) put the vacuum bag inside an autoclave until it reaches a pressure of between 2 and 4 bar and a temperature of between 75°C and 90°C;

[0052] k) once it reaches the temperature and pressure values indicated in step j) keep them constant for 40 minutes to 60 minutes;

[0053] 1) activate the cooling system of the autoclave until it reaches 70°C;

[0054] m) eliminate the air from the autoclave and open it;

[0055] n) take the obtained product inside the vacuum bag out of the autoclave;

[0056] o) remove the polycarbonate cover;

[0057] p) make sure there are no air bubbles between the films;

[0058] q) put the obtained product (without the polycarbonate cover and the vacuum bag) inside the autoclave again;

[0059] r) activate the compressor until it reaches a pressure of between 1.5 and 3 bar;

[0060] s) activate the autoclave until it reaches a temperature of between 120°C and 135 °C and a pressure of between 10 bar and 12 bar;

[0061] t) once it reaches the values indicated in step s) deactivate the compressor and the autoclave until the temperature lowers below 120°C;

[0062] u) activate the cooling system of the autoclave until it reaches 70°C;

[0063] v) eliminate the air from the autoclave and open it;

[0064] w) take the obtained product (the safety glass) out of the autoclave;

[0065] x) let it reach room temperature;

[0066] y) polish the excess of films. [0067] A second exemplary realization, comprises the same steps as the example above, with the addition of step z). That is to say, the complete procedure comprises the following steps:

[0068] a) thorough cleaning of the original glass;

[0069] b) ionize with ionizing gun at least one PVB film;

[0070] c) insert at least one PVB film on the interior face of the original glass;

[0071] d) ionize with ionizing gun at least one C-PET film;

[0072] e) place at least one C-PET film over at least one PVB film;

[0073] f) cut the excess of PVB and C-PET films by the edges;

[0074] g) place a cover of polycarbonate, generally with a density of between 1.5 and 4 mm, over the last C-PET film;

[0075] h) place the product obtained from steps a) to g) inside a vacuum bag;

[0076] i) vacuum the obtained product;

[0077] j) put the vacuum bag inside an autoclave until it reaches a pressure of between 2 and 4 bar and a temperature of between 75°C and 90°C;

[0078] k) once it reaches the temperature and pressure values indicated in step j) keep them constant for 40 minutes to 60 minutes;

[0079] 1) activate the cooling system of the autoclave until it reaches 70°C;

[0080] m) eliminate the air from the autoclave and open it; [0081] n) take the obtained product inside the vacuum bag out of the autoclave;

[0082] o) remove the polycarbonate cover;

[0083] p) make sure there are no air bubbles between the films;

[0084] q) put the obtained product (without the polycarbonate cover and the vacuum bag) inside the autoclave again;

[0085] r) activate the compressor until it reaches a pressure of between 1.5 and 3 bar;

[0086] s) activate the autoclave until it reaches a temperature of between 120°C and 135 °C and a pressure of between 10 bar and 12 bar;

[0087] t) once it reaches the values indicated in step s) deactivate the compressor and the autoclave until the temperature lowers below 120°C;

[0088] u) activate the cooling system of the autoclave until it reaches 70°C;

[0089] v) eliminate the air from the autoclave and open it;

[0090] w) take the obtained product (the safety glass) out of the autoclave;

[0091] x) let it reach room temperature;

[0092] y) polish the excess of films.

[0093] z) place a safety film over the exterior face of the original glass to be reinforced.

[0094] Finally, a third procedure, which is used for an exemplary realization which comprises the use of PVB and C-PET films in both the interior and exterior faces of the tempered glass, is as follows: [0095] a) thorough cleaning of the original glass;

[0096] b) ionize with ionizing gun at least one PVB film;

[0097] c) insert at least one PVB film on the interior face of the original glass;

[0098] d) ionize with ionizing gun at least one C-PET film;

[0099] e) place at least one C-PET film over at least one PVB film;

[00100] f) repeat steps b) to e) applying these to PVB and C-PET films on the exterior face of the glass to be reinforced;

[00101] g) cut the excess of PVB and C-PET films from the interior and exterior faces of the original glass;

[00102] h) place a polycarbonate cover (generally with a density of 1.5 to 4 mm) over the last C- PET films (both in the exterior and the interior faces of the original glass);

[00103] i) place the obtained product formed in steps a) to h) inside a vacuum bag;

[00104] j) vacuum the obtained product;

[00105] k) put the vacuum bag inside an autoclave until it reaches a pressure of between 2 bar and 4 bar and a temperature of between 75°C and 90°C;

[00106] 1) once it has reached the temperature and pressure values indicated in step k) keep them constant for 40 minutes to 60 minutes;

[00107] m) activate the cooling system of the autoclave until it reaches 70°C; [00108] n) eliminate the air from the autoclave and open it;

[00109] o) take the obtained product inside the vacuum bag out of the autoclave;

[00110] p) remove the polycarbonate cover;

[00111] q) make sure there are no air bubbles between the films;

[00112] r) put the obtained product (without the polycarbonate cover and the vacuum bag) inside the autoclave again;

[00113] s) activate the compressor until it reaches a pressure of between 1.5 and 3 bar;

[00114] t) activate the autoclave until it reaches a temperature of between 120 and 135 °C and a pressure of between 10 bar and 12 bar;

[00115] u) once it reaches the pressure and temperature values indicated in steps s) and t), deactivate the compressor and the autoclave until the temperature lowers below 120°C;

[00116] v) activate the cooling system of the autoclave until it reaches 70°C;

[00117] w) eliminate the air from the autoclave and open it;

[00118] x) take the obtained product (the safety glass) out of the autoclave;

[00119] y) let it reach room temperature;

[00120] z) polish the excess of the films.

[00121] The revolutionary aspect of this last "sandwich-type" procedure, where the laminated glass is bonded to both polymer films, is that it eliminates the risk of cuts, lacerations, or injuries of any kind in the event that the tempered glass is damaged or broken. This is because all fragments of the laminated glass would stay adhered to either the internal or external polymer layers, or both. As those of skill in this field would understand, this aspect arises from the procedure itself. The fact that the purpose of this description is to enable an ordinary person to put the invention into practice, should not leave aside the broadness of this application. That is to say, minor modifications, for instance in the number of films used (materials), their density, the temperatures and/or pressures of the autoclave during the diverse stages of the procedure to obtain the safety glass, etc., are taken into consideration in the present invention.