Synthetic fabric with improved optical transparency

Abstract

A fabric formed by weaving monofilaments (2) of synthetic material and having two opposing metallized surfaces, at least one of said surfaces having at least one color (5) that determines the level of transparency. Compared to conventional fabrics for forming transparent panels for the architectural sector, the fabric according to the invention has the advantage that the level of transparency to light can be controlled depending on the color applied to the metallized surface of the fabric.

Description

[Technical Field]

[0001] The present invention relates to a synthetic fabric with improved optical transparency effects.

[0002] The field of the invention is that of synthetic material fabrics, which are used, for example, in the manufacture of laminated glass or plastic panels with a shading effect in the building sector. [Background technology]

[0003] Currently, laminated glass, particularly for use in building facades, is known that can reflect light on the outside of the building while simultaneously being transparent on the inside of the facade. This result can be achieved, for example, by using a glass film or by incorporating a fabric that is metallized on only one side into the glass or transparent plastic. The metallized side, incorporated between two sheets of glass or transparent plastic, faces the outside of the building and reflects light, providing shading and privacy to observers outside, while the non-metallized side is perceived as transparent to observers inside the building.

[0004] The main drawback of the above-mentioned conventional panels is represented by the fact that the level of transparency of the fabric at which the desired privacy effect is achieved is determined not only by the free surface area of ​​the fabric or the percentage of openings in the mesh forming the fabric, but also by the metal coating applied to form the metallized surface of the synthetic material fabric, which limits conventional panels to reproducing the classic "one-way mirror" effect, which is closely related to the absence of a metal coating on one side of the fabric. Summary of the Invention [Means for solving the problem]

[0005] The primary object of the present invention is to provide a fabric made of synthetic materials that can adjust the perceived light privacy or transparency effect with different gradations on both sides of the fabric.

[0006] This and other objects are achieved by the fabric and method of claims 1 and 10, respectively. Preferred embodiments of the invention are given by the remaining claims.

[0007] In relation to conventional fabrics for producing transparent panels in the architectural field, the fabric of the present invention offers the advantage of allowing control of the perceived transparency effect based on the color applied to one or both of the metallized surfaces of the fabric.

[0008] A further advantage of the present invention is represented by the possibility of producing, on the same metallized surface, a variable and adjustable optical transparency effect on the surface itself. [Brief explanation of the drawings]

[0009] These and other objects, advantages and features will emerge from the following description of some preferred embodiments of the fabric of the present invention, illustrated by way of non-limiting example in the accompanying drawings.

[0010] [Figure 1] 1 is a cross-sectional view of a first embodiment of a fabric of the present invention, metallized on both sides and having a color coating on only one of the metallized surfaces. [Figure 2] FIG. 2 is a cross-sectional view showing details of a filament used in producing the fabric of FIG. 1. [Figure 3] FIG. 1 is a cross-sectional view of another embodiment of the fabric of the present invention, in which a color layer is applied to both metallized surfaces of the fabric. [Figure 4] FIG. 4 is a cross-sectional view showing a detail of a filament in the fabric of FIG. 3. [Figure 5]1 shows a front view of an example of a fabric of the present invention, with a metallized side printed with a color gradient to control the transparency effect of the same side. [Figure 6] FIG. 4 is a cross-sectional view showing an example of a panel obtained using the fabric of FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0011] The fabric of the present invention, generally designated 1 in Figure 1, comprises a fabric 4 made of a sheet material woven from filaments 2, preferably monofilaments of a synthetic material such as polyester, and the mesh formed by the woven filaments is calibrated to form a precision fabric with uniform openings. Preferably, the open area of ​​the mesh occupies 15-80% of the surface of the fabric 4.

[0012] According to the present invention, the surfaces of both opposing sides of the fabric sheet are metallized by coating them with a layer 3 of a metal such as aluminum, copper, etc. The metallization process can be carried out under vacuum by galvanic processes of electrodeposition, sputtering, or vapor deposition, as described, for example, in US 2015 / 0345074 A1.

[0013] According to the invention, a color layer 5 is applied to at least a portion of the metallized outer surface 3 of the monofilaments 2 (and therefore the fabric 4 they form) and is fixed by printing a semi-transparent acrylic ink, in particular with UV crosslinking, onto the same surface by digital printing, sublimation or the like, followed by passing under a UV lamp.

[0014] Suitable examples of inks for use in the present invention include, for example, ANAPURNA 1500 RTR CYAN INK, ANAPURNA 1500 RTR BLACK INK, ANAPURNA 1500 RTR YELLOW INK, ANAPURNA 1500 RTR MAGENTA INK, and ANAPURNA 1500 RTR CYAN INK, manufactured by Agfa Graphics NV (Belgium).

[0015] The presence of this color layer 5 results in a perceived transparency on the metallized surface 3 of the fabric 4, which depends on the brightness percentage of the selected shade. Indeed, the reflected light energy of the metallized surface 3 is greater when the color selected to form the color layer 5 has a high brightness percentage (by brightness, which means one of the three color characteristics described in "A Color Nation: An Illustrated System Defining All Colors and Their Relations" 1941 by A.H. Munsell 2004-10-15), while it is smaller when the brightness percentage is lower.

[0016] Also, considering chromatic colors and dividing them into pure color families, yellow and green are used to show that the perceived shading properties of a fabric are greater than those of red and blue at the same lightness. This shading effect is directly proportional to the measured total average reflectance in the visible light range (380-780 nm).

[0017] Thus, according to the invention, the natural reflection of light on the metallized surface 3 of the fabric 4 is modified by the choice of color printed on the metallized surface, in a more or less obscuring sense, so that the other metallized surfaces of the fabric not treated with color will, thanks to the reflective capacity of the metallized surfaces not covered with color, make the color applied to the opposite side brighter.

[0018] In the variant shown in Figures 3 and 4, the color layer 5 is applied to the entire metallized surface of the monofilament 2. In this way, both metallized faces of the fabric 4 have a color coating 5. In this embodiment, with the help of color it is possible to give the fabric two opposing faces with an adjustable transparency effect.

[0019] In the embodiment of the invention shown in Figure 5, a colour layer 5 is applied to one or both metallised surfaces 3 of a fabric 4, for example having a colour tone distributed in colour bands 5a, 5b, 5c, 5d on said metallised surface. The colour can be applied in the form of spot colours, gradations or in the form of decorative or fantasy motifs such as patterns.

[0020] In this way, it is possible to obtain different gradients of optical transparency on the same metallized surface of the fabric of the invention, depending on the different shades of the color layer 5 applied onto this surface, a result that is particularly advantageous when different levels of privacy are desired on the same shading surface.

[0021] As shown in Figure 6, with the fabric of the invention it is possible to obtain a panel incorporating the same fabric in a sandwich structure completed by two sheets 6 of glass or transparent plastic. In the case of the glass sheets, two layers 7 of polymeric sealant are also used to hold them together.

[0022] The fabric sheets according to the invention can be used in interior design as stretch panels or dividers, or integrated inside two sheets of glass or plastic. In the glass sector, gradients are mainly formed using conventional ceramic frits, which always have color limitations and do not allow for flexible customization services, or more rarely using digital printing on EVA (a very fragile and expensive polymer interlayer). Digital printing of gradients on metallized fabrics, which are then integrated into the glass, represents an interesting alternative from an industrial, functional, and aesthetic point of view. [Example]

[0023] The present invention will now be described with reference to the following examples, which are given solely for the purpose of non-limiting illustration of the invention.

[0024] Example 1 : When the fabric has color printing on one side and no color printing on the other side In this example, a 145 μm diameter polyester monofilament fabric was prepared, with a sheet thickness of 255 μm and a free surface area of ​​44%. Both surfaces of this sheet were metallized with aluminum using a vapor deposition process (described in patent EP2462274B1), and three samples were printed with ink on only one side. Specifically, neutral colors were printed, each distinguished by a different lightness percentage in the original color recipe. The lightness or luminous intensity L value of the finished product, combining the translucent ink and the metallized surface, was measured again using an X-Rite Incorporated Color i7 spectrophotometer. The same spectrophotometer, equipped with a planar diffraction grating operating only in the visible wavelength range (380 nm to 780 nm), was used to measure the spectral reflectance of light on the surface of the color-coated metallized fabric. The measurement was performed in transmission / reflection mode (geometry D8° - diffuse light with a spectral measurement angle of 8°) using an X-Rite PULS XEN LAMP incandescent lamp as the light source. The computer tool Photoshop® is used to create the print colors and selects the LAB or CIELAB or CIE LAB 1976 color space designed by the CIE (Commission Internationale de l'Eclairage: International Organization for Light, Illumination, Color, and Color Spaces), where L denotes lightness and A and B refer to the color dimensions opposite to the color, i.e., A (red-green) and B (yellow-blue). In this particular case, only the value of L (ciel*) is considered, while the values ​​of A and B remain unchanged.

[0025] To demonstrate how the color lightness ratio affects the average reflectance of the fabric of the present invention, a black (ANAPURNA 1500 RTR BLACK INK) of L=100 ciel* and a medium gray of L=50 ciel* were printed, and as an extreme reference a very light gray of L=90 ciel*, where the gray was obtained by printing a smaller amount of black ink.

[0026] The results are shown in Table 1 below. "Theoretical L Print File" represents the lightness values ​​entered into the print file according to the LAB color space. "L measured on fabric" refers to the lightness value measured on a metallized fabric printed with semi-transparent ink using a color recipe containing a theoretical reference L, using an X-Rite Color i7 model spectrophotometer.

[0027] On the other hand, "Measured reflectance (%)" represents the total reflectance in the visible range (380-780 nm) measured using an X-Rite Color i7 spectrophotometer in transmission-reflection mode with a geometry of D: 8°, where D is the illumination caused by diffuse light, 8° is the measurement angle of the spectrum, and the light source used is an X-Rite PULS XENO LAMP incandescent lamp.

[0028] Since it is an achromatic color, the coordinates of A and B are always 0, which is why they are not included in the table.

[0029] [Table 1]

[0030] The results showed that the reflectance of metallized fabrics was affected by the amount of lightness included in the color recipe of the print file, ranging from a minimum percentage of 26.16% to a maximum percentage of 58.903% for the samples examined.

[0031] Example 2 : When color is applied to both sides of the fabric In this example, a polyester monofilament fabric with a diameter of 145 μm was prepared, with a sheet thickness of 255 μm and a free surface area of ​​44%. Both sides of this sheet were metallized with aluminum by vapor deposition as in Example 1, and three samples were prepared with color printing on both sides. In particular, achromatic ink was used as in Example 1, but this time, the opposite side, printed with a red chromatic ink (ANAPURNA 1500 RTR MAGENTA INK), was measured to demonstrate how one side affects the other. The same equipment and method were used as in Example 1.

[0032] The results are shown in Table 2 below. [Table 2]

[0033] The results showed that the reflectance of one surface is affected by the reflectance of the other surface, and this is determined by the degree of brightness of the printed color.

[0034] Example 3 : When color is applied to one side of the fabric and the other side is not color printed. In this example, a 145 μm diameter polyester monofilament fabric was prepared, with a sheet thickness of 255 μm and a free surface area of ​​44%. Both sides of this sheet were metallized with aluminum by vapor deposition, as in Example 1, and four samples were printed in color on only one side of the fabric. To verify that yellow and green reflect more than red and green at the same light intensity (L) using the LAB model, theoretical colors were created using the base chromatic inks ANAPURNA 1500 RTR CYAN INK, ANAPURNA 1500 RTR BLACK INK, ANAPURNA 1500 RTR YELLOW INK, ANAPURNA 1500 RTR MAGENTA INK, and ANAPURNA 1500 RTR CYAN INK: yellow and blue with opposite values ​​of B, and blue and red with opposite values ​​of A. The L values ​​of the finished product, combining translucent inks with a metal surface, were then measured again using an X-Rite Color i7 spectrophotometer. The spectral reflectance of light on the color-coated metallized fabric surface was measured using the same spectrophotometer used in Example 1, equipped with a planar diffraction grating that operates only in the visible wavelength range (380 nm to 780 nm).

[0035] The results are shown in Table 3 below. "A print file" represents the numerical value of A entered into the print file according to the LAB color space to create a color recipe. "B print file" represents the numerical value of B entered into the print file according to the LAB color space to create a color recipe. "Measured reflectance" refers to the total reflectance in the visible range (380-780 nm) measured using an X-Rite spectrophotometer in reflectance mode with a D-8° geometry. The value of L is not included in the table because it remains constant at 60ciel*. Only the coordinates of A and B change.

[0036] [Table 3]

[0037] The results show that the surface of the metallized fabric of the present invention printed with colors of equal brightness and opposite color dimensions appears slightly more reflective and therefore more opaque when the colors printed on the surface fall into the yellow and green categories. Similar results can be achieved with colors applied in different ways and in different shades.

Claims

1. A fabric formed from a sheet material woven with filaments, A fabric characterized in that the surfaces of both opposing sides of the sheet material are metallized, and one side of the metallized surface has at least one color (5) made of semi-transparent ink for adjusting the effect of transparency of the fabric to light, or both sides of the metallized surface have colors (5) made of semi-transparent ink for adjusting the effect of transparency of the fabric to light, and the colors (5) on both sides are different.

2. the translucent ink is an acrylic ink having ultraviolet crosslinking, 2. The fabric of claim 1, wherein said at least one color (5) has two or more colors and comprises a plurality of areas on the same surface of said at least one metallized surface having different tones, providing a transparency gradient that is a function of the color (5).

3. 3. Fabric according to claim 1 or 2, characterized in that both sides of the metallized surface have at least one color (5).

4. 3. The fabric according to claim 1 or 2, characterized in that the at least one metallized surface has a plurality of areas on the same surface with different color tones.

5. 5. The fabric of claim 4, wherein said color tone is distributed on both metallized surfaces of said sheet material.

6. 3. Fabric according to claim 1 or 2, characterized in that the filaments are monofilaments (2) and the fabric is a fabric with controlled mesh openings.

7. A panel of this type comprising at least two sheets of transparent material between which is held one or more fabrics according to any one of claims 1 to 6.

8. 1. A method for controlling and adjusting the light transparency effect of a synthetic material fabric having a metal coating on both opposing sides, comprising: applying at least one color (5) consisting of a semi-transparent ink to at least one of said metallized surfaces, thereby giving said at least one metallized surface a transparency to light as a function of said at least one color (5); A method characterized in that if both sides of said metallized surface have at least one color (5), the colors of both sides are different colors.

9. 9. The method of claim 8, wherein at least one of said metallized surfaces has a plurality of regions on the same surface having different tones.

10. 9. The method of claim 8, wherein the semi-transparent ink is an acrylic ink with UV photocrosslinking.

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