CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of Korean Patent Application No. 10-2019- 0164989, filed on December 11, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

1. Field

[0002] The present disclosure relates to a glass laminate and a method of manufacturing the glass laminate. More particularly, the present disclosure relates to a glass laminate including a pattern layer with a non-uniform thickness and a method of manufacturing the glass laminate.

2. Description of Related Art

[0003] A glass laminate may include a glass layer attached to a substrate. Glass laminates may be used in a variety of applications, such as interior and/or exterior decorations of buildings, home appliances, furniture, etc.

SUMMARY

[0004] The present disclosure provides a glass laminate with an aesthetically enhanced appearance.

[0005] Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure.

[0006] According to an aspect of the present disclosure, there is provided a glass laminate including a substrate; a pattern layer disposed on the substrate and having an uneven upper surface; a transparent planarization layer disposed on the pattern layer; a transparent adhesive layer disposed on the transparent planarization layer; and a glass layer disposed on the transparent adhesive layer, wherein a waviness of an upper surface of the transparent planarization layer is less than that of the upper surface of the pattern layer, and wherein a yellowness index of the transparent adhesive layer is less than that of the transparent planarization layer.

[0007] In some embodiments, an average thickness of the transparent planarization layer may be 1.5 times or more the waviness of the upper surface of the pattern layer and 200 pm or less.

[0008] In some embodiments, a yellowness index of the glass laminate by the transparent planarization layer and the transparent adhesive layer may be 1.8 or less. [0009] In some embodiments, a waviness of an upper surface of the glass layer may be 0 to 10 pm.

[0010] In some embodiments, an average thickness of the glass layer may be 0.1 mm to 1.0 mm.

[0011] In some embodiments, an absolute value of a difference in a refractive index between the transparent planarization layer and the transparent adhesive layer at a wavelength of 632.8 nm may be 0 to 0.2.

[0012] In some embodiments, an absolute value of a difference in a refractive index between the transparent adhesive layer and the glass layer at a wavelength of 632.8 nm may be 0 to 0.2.

[0013] In some embodiments, a Young's modulus of the transparent adhesive layer may be less than that of the transparent planarization layer.

[0014] In some embodiments, the pattern layer may not be transparent.

[0015] According to another aspect of the present disclosure, there is provided a method of manufacturing a glass laminate including forming a pattern layer having an uneven upper surface on a substrate; forming a transparent planarization layer in a liquid state on the pattern layer; curing the transparent planarization layer; and adhering a glass layer to the transparent planarization layer using a transparent adhesive layer, wherein a waviness of an upper surface of the transparent planarization layer is less than that of the upper surface of the pattern layer, and wherein a yellowness index of the transparent adhesive layer is less than that of the transparent planarization layer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: [0017] FIG. 1 is a cross-sectional view of a glass laminate according to an embodiment of the present disclosure;

[0018] FIG. 2 is a flowchart illustrating a method of manufacturing a glass laminate according to an embodiment of the present disclosure; and

[0019] FIGS. 3A and 3B are cross-sectional views illustrating operations of manufacturing a glass laminate according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0020] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of," when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

[0021] As used herein, the expression "about" value means from 90% of the value to 110% of the value, for example, from 95% of the value to 105% of the value, for example, from 99% of the value to 101% of the value.

[0022] The expression that a layer is transparent means that the transmittance of the layer is about 90% or more, for example, about 95% or more, for example, about 99% or more, in a visible ray range, for example, in the range of about 380 nm to about 780 nm. To the contrary, the expression that a layer is not transparent means that the transmittance of the layer is less than about 90%, for example, less than about 95%, for example, less than about 99% in the visible ray range.

[0023] The expression that a first object is disposed on a second object means that not only the first object is disposed directly on the second object but also an intervening object may be disposed between the first object and the second object.

[0024] Waviness of a surface refers to a height difference between the highest and lowest points of the surface. In addition, a yellowness index of a layer is defined by ASTM D1925. A yellowness index of a glass laminate is defined by a yellowness index of a transparent planarization layer and a transparent adhesive layer. [0025] Average thickness is defined as a value obtained by dividing the volume of an object by the planar area of the object. Further, the expression that a layer has a uniform thickness means that the variation in thickness of the layer is within about 10% of the average thickness, for example, within about 5%, for example, within about 1%. In addition, the expression that the surface of a layer is flat means that waviness of the surface of the layer is 0 to about 10 pm, for example, 0 to about 5 pm, for example, 0 to about 1 pm.

[0026] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, these embodiments are for illustrative purposes and the spirit of the present disclosure is not limited to these embodiments.

[0027] FIG. 1 is a cross-sectional view of a glass laminate 100 according to an embodiment of the present disclosure.

[0028] Referring to FIG. 1, the glass laminate 100 according to an embodiment includes a substrate 110, a pattern layer 120, a transparent planarization layer 130, a transparent adhesive layer 140, and a glass layer 150.

[0029] The substrate 110 may include any material, such as an organic material, an inorganic material, or a combination thereof. The substrate 110 may include, for example, wood, a metal, ceramic, a polymer, or a combination thereof. The substrate 110 may include, for example, but is not limited to, a Medium Density Fiberboard (MDF), a High-Pressure Laminate (HPL), steel, or a combination thereof. In some embodiments, the substrate 110 may not be transparent. In some embodiments, the average thickness of the substrate 110 may be about 1.0 mm to about 2.0 mm. In some embodiments, the substrate 110 may have a uniform thickness. In some embodiments, the upper and lower surfaces of the substrate 110 may be flat.

[0030] The pattern layer 120 may be disposed on the substrate 110. The pattern layer 120 displays an image for improving the aesthetic appearance of the glass laminate 100. The pattern layer 120 may be visible outside of the glass laminate 100 through the transparent planarization layer 130, the transparent adhesive layer 140, and the glass layer 150. The pattern layer 120 may exhibit various colors, shapes, and/or textures. In some embodiments, the pattern layer 120 may include polyester, melamine, acrylic, polyurethane, epoxy, polyvinyl chloride (PVC), or a combination thereof, but is not limited thereto. The pattern layer 120 may not be transparent. The pattern layer 120 may have a non-uniform thickness. In some embodiments, the average thickness of the pattern layer 120 may be about 10 p to about 100 pm. The upper surface of the pattern layer 120 may not be flat. In some embodiments, waviness of the upper surface of the pattern layer 120 may be about 10 pm to about 100 pm. In some embodiments, the lower surface of the pattern layer 120 may be flat.

[0031] The transparent planarization layer 130 may be disposed on the pattern layer 120. The transparent planarization layer 130 may include, for example, acrylic polymer, epoxy polymer, urethane polymer, polyethylene terephthalate (PET), polypropylene (PP), PVC, polyvinyl butyral (PVB), polycarbonate (PC), ethylene vinyl acetate (EVA), or a combination thereof, but is not limited thereto. The transparent planarization layer 130 may be transparent. In some embodiments, a refractive index of the transparent planarization layer 130 at a wavelength of 632.8 nm may be about 1.3 to about 1.6, for example, about 1.40 to about 1.55. Waviness of the upper surface of the transparent planarization layer 130 may be less than the waviness of the pattern layer 120. In some embodiments, the lower surface of the transparent planarization layer 130 may not be flat while the upper surface of the transparent planarization layer 130 may be flat. For example, the waviness of the upper surface of the transparent planarization layer 130 may be 0 to about 10 pm. That is, the transparent planarization layer 130 may at least partially offset the non-uniform thickness of the pattern layer 120, and the transparent planarization layer 130 may have a non-uniform thickness. In some embodiments, the average thickness of the transparent planarization layer 130 may be about 10 pm to about 200 pm. In order to prevent an image of the pattern layer 120 from being distorted when viewed from the outside of the glass laminate 100, the upper surface of the transparent planarization layer 130 may be flat and the waviness of the glass layer 150 may be reduced. In this case, the average thickness of the transparent planarization layer 130 may be about 1.5 times or more the waviness of the upper surface of the pattern layer 120. Also, in order to prevent the image of the pattern layer 120 from being distorted when viewed from the outside of the glass laminate 100 due to the yellowing of the transparent planarization layer 130, the average thickness of the transparent planarization layer 130 may be about 200 pm or less.

[0032] The transparent adhesive layer 140 may be disposed on the transparent planarization layer 130. The transparent adhesive layer 140 may include, for example, an optically clear adhesive. The transparent adhesive layer 140 may include, for example, silicone gel, transparent silicone, acrylic gel, polyolefin gel, polyurethane gel, butadiene gel, isoprene gel, butyl gel, styrene-butadiene gel, ethylene-vinyl acetate copolymer gel, ethylene-propylene-diene copolymer gel, fluoro gel, or combinations thereof. The transparent adhesive layer 140 may be transparent. In some embodiments, the refractive index of the transparent adhesive layer 140 at a wavelength of 632.8 nm may be about 1.3 to about 1.6, for example, about 1.40 to about 1.55. A yellowness index of the transparent adhesive layer 140 is less than a yellowness index of the transparent planarization layer 130. The transparent adhesive layer 140 has a relatively low yellowness index compared to the transparent planarization layer 130, thereby preventing the image of the pattern layer 120 from being distorted when viewed from the outside of the glass laminate 100 due to yellowing of the transparent adhesive layer 140. In some embodiments, the average thickness of the transparent adhesive layer 140 may be about 10 pm to about 150 pm. In some embodiments, the transparent adhesive layer 140 may have a uniform thickness. In some embodiments, the upper and lower surfaces of the transparent adhesive layer 140 may be flat. For example, waviness of the upper and lower surfaces of the transparent adhesive layer 140 may be 0 to about 10 pm. The transparent adhesive layer 140 may have a relatively small Young's modulus compared to the transparent planarization layer 130, and thus the transparent adhesive layer 140 may mitigate an external impact applied to the glass laminate 100. The transparent adhesive layer 140 may prevent the glass layer 150 from being broken and may prevent glass pieces from scattering even when the glass layer 150 is broken. For example, the Young's modulus of the transparent adhesive layer 140 may be about 0.01 MPa to about 1 MPa, for example, about 0.05 MPa to about 0.5 MPa, and the Young's modulus of the transparent planarization layer 130 may be about 0.1 MPa to about 10 GPa, for example, about 1 MPa to about 10 GPa.

[0033] The glass layer 150 may be disposed on the transparent adhesive layer 140. The glass layer 150 may include soda lime glass, borosilicate glass, aluminosilicate glass, boroaluminosilicate glass, or a combination thereof. The glass layer 150 may be transparent. In some embodiments, the refractive index of the glass layer 150 at a wavelength of 632.8 nm may be about 1.50 to about 1.53. In some embodiments, the glass layer 150 may have a uniform thickness. In some embodiments, the average thickness of the glass layer 150 may be about 0.1 mm to about 1.0 mm. When the average thickness of the glass layer 150 is about 1.0 mm or more, the transparent flattening layer 130 may not be necessary because the glass layer 150 is sufficiently thick so that waving of the glass layer 150 is negligible. When the average thickness of the glass layer 150 is about 0.1 mm or less, the glass layer 150 may be too thin, which makes it difficult to manufacture the glass laminate 100 and the glass laminate 100 may not have sufficient mechanical strength.

[0034] According to an embodiment of the present disclosure, the transparent planarization layer 130 may reduce waving of the glass layer 150 caused by the non- uniform thickness of the pattern layer 120, and thus the distortion of the image of the pattern layer 120 caused by waving of the glass layer 150 when viewed from the outside of the glass laminate 100 may be reduced. For example, the waviness of the upper surface of the glass layer 150 may be 0 to about 10 pm. That is, the upper surface of the glass layer 150 may be flat. In addition, the transparent adhesive layer 140 having the yellowness index less than the yellowness index of the transparent planarization layer 130 may reduce the distortion of the image of the pattern layer 120 caused by yellowing when viewed from the outside of the glass laminate 100. For example, the yellowness index of the glass laminate 100 based on both the transparent planarization layer 130 and the transparent adhesive layer 140 may be less than or equal to about 1.8 or less, for example, about -1.8 to about 1.8. In addition, in order to prevent distortion of the image of the pattern layer 120 due to the refraction of light when viewed from the outside of the glass laminate 100, an absolute value of the refractive index difference between the transparent planarization layer 130 and the transparent adhesive layer 140 and an absolute value of the refractive index difference between the transparent adhesive layer 140 and the glass layer 150 may be minimized. For example, the absolute value of the refractive index difference between the transparent planarization layer 130 and the transparent adhesive layer 140 at a wavelength of 632.8 nm may be 0 to about 0.2, and the absolute value of the refractive index difference between the transparent adhesive layer 140 and the glass layer 150 at the wavelength of 632.8 nm may be 0 to about 0.2. In some embodiments, the transparent planarization layer 130, the transparent adhesive layer 140, and the glass layer 150 may have the same refractive index. Thus, the glass laminate 100 according to an embodiment of the present disclosure may have an aesthetically improved appearance.

[0035] FIG. 2 is a flowchart illustrating a method 200 of manufacturing the glass laminate 100 according to an embodiment of the present disclosure. FIGS. 3A and 3B are cross-sectional views illustrating operations of manufacturing the glass laminate 100 according to an embodiment of the present disclosure.

[0036] Referring to FIGS. 2 and 3A, the pattern layer 120 having a non-uniform thickness is formed on the substrate 110 (S210). The pattern layer 120 may be printed on the substrate 110. For example, the pattern layer 120 may be formed by ink jet printing or screen printing.

[0037] Referring to FIGS. 2 and 3B, the transparent planarization layer 130 is formed in a liquid state on the pattern layer 120 (S220). For example, the transparent planarization layer 130 may be formed by screen printing, slot die coating, or curtain coating. The upper surface of the transparent planarization layer 130 formed in the liquid state may be planarized by gravity and surface tension. For example, the upper surface of the transparent planarization layer 130 may be formed to be flat, that is, have waviness of 0 to about 10 pm. Next, the transparent planarization layer 130 is cured by, for example, heat, light, such as ultraviolet rays or a combination thereof (S230). In some embodiments, a flat sheet (not shown) is placed on the transparent planarization layer 130 in the liquid state, and a force is applied to the flat sheet to planarize the upper surface of the transparent planarization layer 130 and also cure the transparent planarization layer 130. Thereafter, the flat sheet may be removed from the transparent planarization layer 130.

[0038] Referring to FIGS. 2 and 1, the glass layer 150 is attached to the transparent planarization layer 130 using the transparent adhesive layer 140 in the form of a sheet or a tape (S240). The transparent adhesive layer 140 may not require curing.

[0039] Experimental Example

[0040] Samples based on the first to third embodiments were prepared according to the method 200 (see FIG. 2) of manufacturing the glass laminate 100 according to the present disclosure. In the samples of the first to third embodiments, the waviness of the upper surface of the pattern layer was about 30 pm, the average thickness of the transparent adhesive layer was about 50 pm, and the average thickness of the glass layer was about 250 pm. In the samples of the first to third embodiments, the average thickness of the transparent planarization layer was about 17 pm, about 62 pm, and about 236 pm, respectively. In the comparative sample, waviness of the upper surface of the pattern layer was about 30 pm, the average thickness of the transparent adhesive layer was about 50 pm, and the average thickness of the glass layer was about 250 pm, as in the samples of the first to third embodiments, but the glass substrate 100 of the comparative sample did not include a transparent planarization layer. Regarding the comparative sample and the samples of the first to third embodiments, the average thickness of the transparent planarization layer, the average thickness of the transparent adhesive layer, the refractive index of the transparent planarization layer, and the refractive index of the transparent adhesive layer are shown in Table 1 below.

[0041] The waviness of the upper surface of the glass layer of the comparative sample and the samples of the first to third embodiments was measured over a length of about 5 cm by using DektakXT from Bruker. Yellowness indexes of the comparative sample and the samples of the first to third embodiments were measured by using Minolta's CM-2600D according to ASTM D1925. The waviness and yellowness indexes of the upper surface of the glass layer measured with respect to the comparative sample and the samples of the first to third embodiments are shown in Table 1 below.

[0042] Table 1

Ό043] Referring to T able 1 , as the average thickness of the transparent planarization layer increases, the waviness of the upper surface of the glass layer decreases whereas the yellowness index of the glass laminate increases. It may be seen that the waviness of the upper surface of the glass layer of the samples of the second and third embodiments having the average thickness of the transparent planarization layer of 45 pm or more, which is 1.5 times the waviness of the upper surface of the pattern layer, is improved by 50% or more compared with the comparative sample. In addition, the yellowness index of the samples of the first and second embodiments having the average thickness of the transparent planarization layer of 200 pm or less may be about 1.8 or less.

[0044] According to an embodiment of the present disclosure, the transparent planarization layer may reduce waving of the glass layer caused by the non-uniform thickness of the pattern layer, and thus, distortion of the image of the pattern layer caused by waving of the glass layer when viewed from outside of the glass laminate may be reduced. In addition, the transparent adhesive layer having a yellowness index less than a yellowness index of the transparent planarization layer may reduce distortion of the image of the pattern layer caused by yellowing when viewed from the outside of the glass laminate. Thus, the glass laminate according to an embodiment of the present disclosure may have an aesthetically improved appearance. In addition, the transparent adhesive layer having a Young's modulus less than the Young's modulus of the transparent planarization layer may mitigate an external impact applied to the glass laminate.

[0045] The embodiments disclosed in the present disclosure are not intended to limit the spirit of the present disclosure but to describe the present disclosure, and the scope of the spirit of the present disclosure is not limited by these embodiments. The scope of the present disclosure should be interpreted by the following claims, and all variations and modifications within the scope equivalent thereto should be construed as being included in the scope of the present disclosure.