SMALL RADII COMPLEX SHAPE LAMINATED GLAZING

Abstract

It is now possible to economically produce, in series production, automotive glazing that has complex small radii feature lines (30). Such feature lines (30) are desirable as they can improve the stiffness of the glazing as well as contribute to the overall aesthetic and differentiation of the vehicle, allowing body lines to blend into and continue in the glazing. However, traditional automotive laminating methods do not lend themselves well to this type of product. Typically, the offset between the mating surfaces of the laminate must be very uniform. Such uniformity is difficult to achieve when producing small radii features. Rather than bending multiple layers with small radii feature lines that can be nested and subsequently laminated using standard plastic automotive interlayers, the invention makes use of a two part method for laminating, a dry lamination process and a wet lamination process, which requires only that the feature lines (30) be present in the outer glass layer (201).

Claims

1. An automotive laminated glazing with small radii features lines comprising: an outer glass layer with small radii feature lines having interior and exterior surfaces; a cured laminating resin; and a first stack of components comprising an inner glass layer having interior and exterior surfaces; and at least one plastic bonding layer facing the interior surface of the inner glass layer; wherein the first stack of components is disposed on and bonded to the interior surface of the outer glass layer by said cured laminating resin, such that the interior surface of the outer glass layer is facing said at least plastic bonding interlayer such that the at least plastic bonding interlayer is located between the inner and outer glass layers.

2. The automotive laminated glazing according to claim 1, wherein the first stack of components further comprising: a middle layer having interior and exterior surfaces; wherein the at least one plastic bonding layer is located between interior surfaces of inner glass layer and middle layer; and wherein the interior surface of the outer glass layer is facing the exterior surface of the middle glass layer.

3. The automotive laminated glazing according to claim 2, wherein the middle layer is made of glass, PET, PC or PMMA.

4. The automotive laminated glazing according to any one of the preceding claims further comprising a solar reflecting coating.

5. The automotive laminated glazing according to any one of the preceding claims, wherein the laminating resin is a liquid optically clear adhesive.

6. The automotive laminated glazing according to any one of the preceding claims, wherein the laminating resin is cured by one of the following: UV radiation, thermal exposition, moisture cure, catalytic reaction, or crosslinking.

7. The laminated glazing according to any one of the preceding claims further comprising spacers between the middle layer and the outer glass layer.

8. The laminated glazing according to any one of the preceding claims further comprising a dam applied to the periphery of the laminated glazing.

9. The laminated glazing according to claim 8, wherein the dam is a spacer.

10. A method for producing an automotive laminated glazing with small radii feature lines comprising the steps of: providing an outer glass layer with small radii feature lines, an inner glass layer, a middle layer, at least one plastic bonding interlayer, a laminating resin; assembling said inner glass layer and said middle layer such that at least one plastic bonding interlayer is located between the adjacent major faces of said layers; processing assembled inner glass layer, middle layer and said at least one plastic bonding interlayer through a standard dry automotive laminating process; assembling outer glass layer with the laminated assembly of previous step; and performing a wet lamination process comprising the steps of: filling the gap between said assembly and outer glass layer with the laminating resin, and curing said laminating resin.

11. The method for producing an automotive laminated glazing according to claim 10, wherein between the steps of processing assembled layers through a standard dry automotive laminating process and assembling outer glass layer with the laminated assembly of previous step, further comprising the step of removing the middle layer from the assembly.

12. The method for producing an automotive laminated glazing according to any one of the claims 10 to 11, wherein the step of assembling outer glass layer with laminated assembly of previous steps comprises the step of providing spacers between the outer glass layer and the laminated assembly.

13. The method for producing an automotive laminated glazing according to claim 12 further comprising the step of applying a dam to the periphery of the assembly.

14. A method for producing an automotive laminated glazing with small radii feature lines comprising the steps of: providing an outer glass layer with small radii feature lines, an inner glass layer, at least one middle glass layer, at least one plastic bonding interlayer, a laminating resin; assembling outer glass layer with middle layer; performing wet lamination process comprising the steps of: filling the gap between said middle layer and outer glass layer with laminating resin, curing said resin; assembling said inner glass layer with the laminated assembly of previous step such that at least one plastic bonding interlayer layer is located between the adjacent major faces of inner glass layer and middle layer; and processing assembled outer layer and middle layer with the inner glass layers and said at least one plastic bonding interlayer through a standard automotive dry laminating process.

15. The method for producing an automotive laminated glazing according to claim 14, wherein the step of assembling outer glass layer with middle glass layer comprises the step of providing spacers between the middle glass layer and the outer glass layer.

16. The method for producing an automotive laminated glazing according to any one of the claims 14 to 15 further comprising the step of applying a dam to the periphery of the assembly.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0036] FIG. 1A shows a cross section of a typical laminated automotive glazing.

[0037] FIG. 1B shows a cross section of a typical automotive glazing with performance film.

[0038] FIG. 1C shows a cross section of a typical tempered monolithic automotive glazing.

[0039] FIG. 2A shows a cross section of a laminated glazing with two identical glass layers.

[0040] FIG. 2B shows a cross section of a laminated glazing with two different glass layers.

[0041] FIG. 2C shows a cross section of a laminated glazing with feature lines in outer layer according to a first embodiment of the invention.

[0042] FIG. 3A shows a cross section of a laminated glazing with three identical layers.

[0043] FIG. 3B shows a cross section of a laminated glazing with three different layers.

[0044] FIG. 3C shows a cross section of a laminated glazing with feature lines in outer layer according to a second embodiment of the invention.

[0045] FIG. 4 shows an exploded view of a laminated glazing according to a first embodiment of the invention.

[0046] FIG. 5 shows an exploded view of a laminated glazing according to a second embodiment of the invention.

[0047] FIG. 6A shows an isometric view of a laminated glazing according to a second embodiment of the invention.

[0048] FIG. 6B shows the cross section AA of FIG. 6C.

[0049] FIG. 6C shows a closeup of feature line cross section AA.

REFERENCE NUMERALS OF DRAWINGS

[0050] 2 Glass

[0051] 4 Bonding/Adhesive Layer (interlayer)

[0052] 6 Obscuration/Black Frit

[0053] 12 Performance Film

[0054] 14 Laminating resin

[0055] 18 Coating

[0056] 30 Feature Line

[0057] 101 Surface one

[0058] 102 Surface two

[0059] 103 Surface three

[0060] 104 Surface four

[0061] 105 Surface five

[0062] 106 Surface Six

[0063] 201 Outer layer

[0064] 202 Inner layer

[0065] 203 Middle layer

DETAILED DESCRIPTION OF THE INVENTION

[0066] The following terminology is used to describe the laminated glazing of the invention.

[0067] The term “glass” can be applied to many organic and inorganic materials, include many that are not transparent. For this document we will only be referring to nonorganic transparent glass. From a scientific standpoint, glass is defined as a state of matter comprising a non-crystalline amorphous solid that lacks the ordered molecular structure of true solids. Glasses have the mechanical rigidity of crystals with the random structure of liquids.

[0068] Glass is formed by mixing various substances together and then heating to a temperature where they melt and fully dissolve in each other, forming a forming a miscible homogeneous fluid.

[0069] Typical automotive laminated glazing cross sections are illustrated in FIGS. 1A and 1B. A laminate is comprised of at least two layers of glass, the exterior or outer, 201 and interior or inner, 202 that are permanently bonded together by a plastic layer 4 (interlayer).

[0070] In a laminate, the glass surface that is on the exterior of the vehicle is referred to as surface one 101 or the number one surface. The opposite face of the exterior glass layer 201 is surface two 102 or the number two surface. The glass 2 surface that is on the interior of the vehicle is referred to as surface four 104 or the number four surface. The opposite face of the interior layer of glass 202 is surface three 103 or the number three surface. Surfaces two 102 and three 103 are bonded together by the plastic layer 4. Additional glass layers may be utilized as is often the case with ballistic resistant glazing in which case they shall be numbered sequentially from the outer layer. In the case of a laminate with three glass layers, there is a middle glass layer 203 having two opposite faces: surface five 105 and surface six 106.

[0071] An obscuration 6 may be also applied to the glass. Obscurations are commonly comprised of black enamel frit printed on either the number two 102 or number four surface 104 or on both.

[0072] The laminate may have a coating 18 on one or more of the surfaces. The laminate may also comprise a film 12 laminated between at least two plastic layers 4.

[0073] FIG. 1C shows a typical tempered automotive glazing cross section. Tempered glazing is typically comprised of a single layer of glass 201 which has been heat strengthened. The glass surface that is on the exterior of the vehicle is referred to as surface one 101 or the number one surface. The opposite face of the exterior glass layer 201 is surface two 102 or the number two surface. The number two surface 102 of a tempered glazing is on the interior of the vehicle. An obscuration 6 may be also applied to the glass. Obscurations are commonly comprised of black enamel frit printed on the number two 102 surface. The glazing may have a coating 18 on the number one 101 and/or number two 102 surface.

[0074] A glazing is an article comprised of at least one layer of a transparent material which serves to provide for the transmission of light and/or to provide for viewing of the side opposite the viewer and which is mounted in an opening in a building, vehicle, wall or roof or other framing member or enclosure.

[0075] Laminates, in general, are articles comprised of multiple sheets of thin, relative to their length and width, material, with each thin sheet having two oppositely disposed major faces and typically of relatively uniform thickness, which are permanently bonded to one and other across at least one major face of each sheet.

[0076] Laminated safety glass is made by bonding at least two sheets (201 & 202) of annealed glass 2 together using a plastic bonding layer comprised of a thin sheet of transparent thermo plastic 4 (interlayer) as shown in FIG. 1.

[0077] Annealed glass is glass that has been slowly cooled from the bending temperature down through the glass transition range. This process relieves any stress left in the glass from the bending process. Annealed glass breaks into large shards with sharp edges. When laminated glass breaks, the shards of broken glass are held together, much like the pieces of a jigsaw puzzle, by the plastic layer helping to maintain the structural integrity of the glass. A vehicle with a broken windshield can still be operated. The plastic layer 4 also helps to prevent penetration by objects striking the laminate from the exterior and in the event of a crash occupant retention is improved.

[0078] The plastic bonding layer 4 (interlayer) has the primary function of bonding the major faces of adjacent layers to each other. The material selected is typically a clear thermoset plastic.

[0079] For automotive use, the most commonly used bonding layer 4 (interlayer) is polyvinyl butyral (PVB). PVB has excellent adhesion to glass and is optically clear once laminated. It is produced by the reaction between polyvinyl alcohol and n-butyraldehyde. PVB is clear and has high adhesion to glass. However, PVB by itself, it is too brittle. Plasticizers must be added to make the material flexible and to give it the ability to dissipate energy over a wide range over the temperature range required for an automobile. Only a small number of plasticizers are used. They are typically linear dicarboxylic esters. Two in common use are di-n-hexyl adipate and tetra-ethylene glycol di-n-heptanoate. A typical automotive PVB interlayer is comprised of 30-40% plasticizer by weight.

[0080] In addition to polyvinyl butyl, ionoplast polymers, ethylene vinyl acetate (EVA), cast in place (CIP) liquid resin and thermoplastic polyurethane (TPU) can also be used. Automotive interlayers are made by an extrusion process with has a thickness tolerance and process variation. As a smooth surface tends to stick to the glass, making it difficult to position on the glass and to trap air, to facilitate the handling of the plastic sheet and the removal or air (deairing) from the laminate, the surface of the plastic is normally embossed contributing additional variation to the sheet. Standard thicknesses for automotive PVB interlayer at 0.38 mm and 0.76 mm (15 and 30 mil).

Description of Embodiments

[0081] FIGS. 3C, 5, 6A, 6B and 6C show a typical embodiment of a laminated glazing having three glass layers. The glazing illustrated is a roof laminate with three feature lines 30. The approximate dimensions are 1200 mm×950 mm.

[0082] The feature lines are only present in the outer glass layer 201 as illustrated in the cross-sections. The feature lines run the length of the laminate. The radii of the curves, on the outer most surface 101, are R1=6 mm and R2=12 mm as illustrated in FIG. 6A.

[0083] The outer layer 201 is first heated and pre-bent to an intermediate stage. Additional localized heat is applied by means of a LASER and then full surface press us used to achieve the final shape with feature lines.

[0084] A middle layer 203 and an inner glass layer 202 are heated and bent to shape separately.

[0085] A black obscuration is screen printed on the inner surface 102 of the outer glass layer 201 and on the inner surface 104 of the inner glass layer 202.

[0086] The outer glass layer 201 is comprised of a clear, 2.1 mm annealed soda-lime glass. The middle layer 203 is also comprised of a clear 2.1 mm annealed soda-lime glass. The middle layer also has a solar reflecting vacuum sputtered coating on the number six surface 106. The inner glass layer 202 is comprised of a 2.1 mm thick dark solar grey soda-lime glass. A dark grey 0.76 mm PVB interlayer 4 is used to laminate the middle layer 203 to the inner layer 202. The total visible light transmission of the compete laminate is less than 5%.

[0087] The gap between the outer 201 and middle glass layer 203 is laminated by means of a wet lamination process using a UV cured laminating resin 14. The middle layer 203 and inner layer 202 are processed using a dry lamination process in which a vacuum is drawn to evacuate any air between the layers, the assembly is heated and then the assembly is placed in an autoclave where heat and pressure are used to permanently bond the two glass layers. The laminated assembly comprising the middle layer 203 and inner glass layer 202 is then laminated to the outer layer 201 with feature lines using a wet process. In this process, spacers (not shown) are installed on the surface five 105 of the dry laminated assembly. The spacers are hidden by the black obscuration and will become a permanent part of the laminate. Then the outer layer with feature lines 201 is matched to the assembly. A polymeric gasket can be applied to the glass providing a seal to prevent the ingress of air and to prevent the liquid laminating resin from escaping during the fill process. A vacuum is drawn as the laminating resin 14 is pumped into the gap between the outer layer 201 and the laminated assembly comprising the plastic bonding interlayer 4, the middle layer 203 and the inner layer 202. The fill is measured so as to prevent under or over filling. A vacuum is maintained for a predetermined period to guarantee the evacuation of all air. The laminating resin 14 is then cured by exposure to high intensity UV light. Other known methods of curing may include a secondary thermal cure, or just thermal cure. The gasket is removed (if any), the edges are trimmed, and the laminate is inspected completing the process.

[0088] FIGS. 2C and 4 show a typical embodiment of a laminated glazing having two glass layers. This embodiment is the same as previous embodiment with the exception that the middle layer 203 is a PET sacrificial plastic layer which is removed after the completion of the dry lamination process. The current laminated assembly comprising at least one plastic bonding interlayer 4 and the inner glass layer 202 is then laminated to the outer layer 201 with feature lines using a wet process (laminating resin). Vacuum may be used to prevent air between the laminated assembly, before resin pumping, pumping in a vacuum environment, or after resin is being pumped to remove any formed bubble.

[0089] Additional embodiments are the same as previous ones with the exception that the inner layer 202 is a plastic layer selected from the group consisting of PC, PMMA and other similar.

[0090] In several embodiments, the laminating resin is a curable Optically Clear Resin (OCR), also known as Liquid Optically Clear Adhesive (LOCA). The laminating resin can be cured by UV radiation, thermal exposition, moisture cure, catalytic reaction, crosslinking, among others. In all the embodiments, the chemical nature of said adhesives can be acrylic, silicone, epoxy, urethane, sulfide based, or combinations thereof.