Flame-retardant polyester decorative sheet

Abstract

The flame-retardant polyester decorative sheet according to an embodiment of the present application includes a core layer containing a polyester resin and a polyphosphonate, and a surface layer located on at least one side of the core layer and containing a polyester resin and a polyphosphonate, wherein the color masterbatch content of the surface layer is greater than that of the core layer, thereby providing a flame-retardant polyester decorative sheet that solves the discoloration problem caused by a flame retardant while satisfying the flame-retardant performance standards of the Korean Fire Service Act No. 2019-2, and thus has a hue deviation equivalent to that of an existing decorative sheet product not using a flame retardant.

Description

Technical Field

[0001] This invention relates to a synthetic resin film with excellent flame retardant properties, and more specifically, to a flame-retardant polyester decorative sheet with excellent flame retardant and fire-retardant properties and a multilayer polyester structure for use in building interior / exterior cladding materials, flooring materials, and other decorative applications. Background Technology

[0002] Generally speaking, decorative sheets are sheets with various colors and patterns that are attached to the surfaces of various office / residential furniture such as closets or desks, or to building materials and interior decoration surfaces to provide users with a variety of visual / tactile effects.

[0003] These decorative panels are manufactured by shaping plastic resins such as polyvinyl chloride (PVC) or polypropylene (PP) into sheets and then applying various colors and patterns to them. As the use of decorative panels with these specific colors and patterns has expanded, in addition to providing simple colors and patterns, panels are now used to offer various visual effects through the application of additional materials to their surface. These decorative panels are widely used as decorative items in various interior spaces.

[0004] Furthermore, unlike polyvinyl chloride (PVC), polyester film, widely used as decorative panels, is non-toxic and boasts excellent appearance quality, meeting environmental protection requirements. However, polyester film is flammable, posing a significant fire hazard. Especially with the occurrence of large-scale fires causing loss of life and property, flame-retardant properties are required for interior and exterior building materials. Consequently, decorative panels also require flame retardancy, thus limiting the use of polyester as a decorative panel.

[0005] To address the flame retardancy issue of decorative panels, flame retardancy is achieved by using decorative panels and interior films molded from polyvinyl chloride (PVC) resin, which possesses relatively excellent flame retardant properties. However, while plasticized PVC materials, previously used as decorative panel materials, have excellent physical properties and moldability, particularly flame retardancy, the use of films with plasticizers added to PVC resin to impart plasticity means that they release toxic gases such as dioxins when burned, thus raising concerns about potential hazards.

[0006] As mentioned above, due to environmental requirements aimed at addressing the toxicity issues of polyvinyl chloride (PVC) decorative sheets, the demand for polyester decorative sheets has increased, necessitating the development of flame-retardant polyester decorative sheets. Summary of the Invention

[0007] Technical issues

[0008] This invention was developed to solve the above-mentioned problems. The problem to be solved by this invention is to provide a flame-retardant polyester decorative sheet, which is a decorative sheet based on polyester resin. The flame-retardant properties are imparted to the polyester decorative sheet, especially meeting the flame-retardant performance standards of Korean Fire and Rescue Agency Announcement No. 2019-2. At the same time, even when flame-retardant properties are imparted, the discoloration problem caused by flame retardants is solved, thus having low color deviation.

[0009] The above and other objects and advantages of this disclosure will become more apparent from the following description of preferred embodiments.

[0010] Solution to the problem

[0011] The above objective is achieved by a flame-retardant polyester decorative sheet comprising: a core layer containing polyester resin and polyphosphonate; and a surface layer located on at least one side of the core layer and containing polyester resin and polyphosphonate.

[0012] Preferably, the flame-retardant polyester decorative sheet may further include a protective coating, which is located on the surface and contains a phosphorus-based flame retardant.

[0013] Preferably, the phosphorus (P) content of the flame-retardant polyester decorative sheet can be from 4,000 ppm to 15,000 ppm.

[0014] Preferably, compared with flame-retardant polyester decorative sheets without added polyphosphonate, the color difference value dE* of the flame-retardant polyester decorative sheet can be less than 0.5.

[0015] Preferably, the polyphosphonate content of the core layer and the surface layer satisfies Formula 1.

[0016] (Equation 1)

[0017] 2.56 ≤ Total thickness of decorative sheet (mm) × Polyphosphonate content (wt%) ≤ 2.58

[0018] Preferably, the tensile strength ratio of the flame-retardant polyester decorative sheet according to Formula 2 can be from 0.7 to 1.

[0019] (Equation 2)

[0020] Tensile strength ratio = Tensile strength of flame-retardant polyester decorative sheet / Tensile strength of decorative sheet without polyphosphonate

[0021] Preferably, the core layer and the surface layer may further include a color masterbatch, which is formed by mixing 10 to 50 parts by weight of colored dye or pigment with 100 parts by weight of polyester resin.

[0022] Preferably, the color masterbatch content in the surface layer can be greater than that in the core layer.

[0023] Preferably, the core layer may comprise 4% to 12% by weight of color masterbatch relative to the total weight of the core layer, and the surface layer may comprise 25% to 35% by weight of color masterbatch relative to the total weight of the surface layer.

[0024] Preferably, the thickness of the flame-retardant polyester decorative sheet can be from 0.20 mm to 0.60 mm.

[0025] The effects of the invention

[0026] According to an embodiment of the present invention, a flame-retardant polyester decorative sheet uses a polyphosphonate flame retardant in each layer of a multilayer polyester decorative sheet, coats a hard coating solution containing a phosphorus flame retardant, and then dries and cures it separately by drying and UV curing to form a protective coating, thereby providing a polyester decorative sheet with flame-retardant properties, and in particular, providing a decorative sheet that meets the flame-retardant performance standards of Korean Fire Services Agency Announcement No. 2019-2.

[0027] Furthermore, according to an embodiment of the present invention, the flame-retardant polyester decorative sheet satisfies flame retardancy while solving the discoloration problem caused by flame retardants, thereby providing a flame-retardant polyester decorative sheet with the same hue deviation as existing decorative sheet products that do not use flame retardants.

[0028] However, the effects of this disclosure are not limited to those described above, and those skilled in the art can clearly understand other effects of this disclosure from the following description. Attached Figure Description

[0029] Figure 1 This is a schematic cross-sectional view of a flame-retardant polyester decorative sheet according to an embodiment of the present invention.

[0030] Figure 2 A flowchart illustrating a method for preparing a flame-retardant polyester decorative sheet according to an embodiment of the present invention. Detailed Implementation

[0031] In the following description, embodiments of the present disclosure will be detailed with reference to the accompanying drawings, enabling those skilled in the art to readily practice the present disclosure. However, the present disclosure can be implemented in various different forms and is not limited to the embodiments provided in this specification.

[0032] In the accompanying drawings, the thickness of layers, films, plates, regions, etc., is enlarged for clarity. Throughout the specification, the same reference numerals denote the same elements. It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it may be directly on the other element or there may be intermediate elements present. Conversely, when an element is referred to as being "directly" on another element, there are no intermediate elements present.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, this specification (including the definitions) shall prevail. Furthermore, while similar or equivalent methods and materials to those described herein may be used in practicing or testing embodiments of the invention, suitable methods and materials are described below.

[0034] Figure 1 This is a schematic cross-sectional view of a flame-retardant polyester decorative sheet according to an embodiment of the present invention.

[0035] See Figure 1 According to an embodiment of the present invention, a flame-retardant polyester decorative sheet may include a core layer 10 containing polyester resin and polyphosphonate, and a surface layer 20 containing polyester resin and polyphosphonate located on at least one side of the core layer 10, and may also include a protective coating 30 containing phosphorus flame retardant formed by coating onto the surface of the surface layer 20.

[0036] According to an embodiment of the present invention, the flame-retardant polyester decorative sheet may have a surface layer 20 stacked on one side of the core layer 10 in a surface layer / core layer stacked structure, or may have a surface layer / core layer / surface layer stacked structure in which the surface layer 20 is stacked on both sides of the core layer 10.

[0037] The core layer 10 is located at the center of the flame-retardant polyester decorative sheet and is formed by mixing polyester resin and polyphosphonate as a flame-retardant material. The outer layer 20 is located outside the core layer 10 and, similarly, is formed by mixing polyester resin and polyphosphonate as a flame-retardant material.

[0038] At this point, the polyester resin constituting the core layer 10 and the surface layer 20 can be a copolyester, and recyclable raw materials can be added as needed to reduce costs.

[0039] The dicarboxylic acid forming the copolyester resin is preferably selected from at least one of the following groups: isophthalic acid, 2,6-naphthalenedicarboxylic acid, sebacic acid, adipic acid, diphenyl dicarboxylic acid, 5-tert-butylisophthalic acid, 2,2,6,6-tetramethyldiphenyl-4,4-dicarboxylic acid, 1,1,3-trimethyl-3-phenylphosphate-4,5-dicarboxylic acid, sodium 5-sulfoisophthalate, trimellitic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, palmitic acid, azelaic acid, pyromellitic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and dimethyl 1,4-cyclohexanedicarboxylate.

[0040] Furthermore, the diol component forming the copolyester resin is preferably selected from at least one group consisting of diethylene glycol, triethylene glycol, hexanediol, pentanediol, diols derived from 2,2-(4-oxyphenol)propane, xylene, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,3-propanediol, 1,2-propanediol, 1,4-cyclohexanediethanol, 1,3-cyclohexanediethanol, 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)sulfone, polytetramethylene glycol, polyethylene glycol, 2-methyl-1,3-propanediol, and 2,2-dimethyl-1,3-propanediol.

[0041] Additionally, as an example, the polyester resin constituting the core layer 10 and the surface layer 20 can be composed of ethylene glycol-modified polyethylene terephthalate (PET-G) and polybutylene terephthalate (PBT).

[0042] The ethylene glycol modified polyethylene terephthalate (PET-G) resin contained in PET-G is an amorphous resin copolymerized from terephthalic acid (TPA), ethylene glycol (EG), and cyclohexanediethanol (CHDM). It possesses excellent processability, moldability, and printability; it does not deform due to shrinkage; it exhibits excellent impact resistance; it does not produce chlorine gas when burned or in a fire; and it is free of harmful components such as endocrine disruptors. Therefore, it is suitable for use as a decorative sheet in this invention.

[0043] Polybutylene terephthalate (PBT) is a crystalline polymer that improves solvent resistance and flexibility when forming a surface layer. Therefore, when a protective coating 30 is applied to the surface layer 20, it prevents the coating liquid from penetrating the surface layer 20, provides high solvent resistance to prevent damage to the core layer 10 and the surface layer 20, and also increases elongation. Furthermore, by incorporating PBT into the core layer 10 and the surface layer 20, the molding temperature can be lowered to increase elongation and to improve white haze.

[0044] In this invention, the thickness of the flame-retardant polyester decorative sheet having a surface / core / surface structure is preferably 0.20 mm to 0.60 mm. If the thickness is less than 0.20 mm, there is a problem of reduced color and strength due to the increased flame retardancy. If the thickness is greater than 0.60 mm, there is a problem of increased cost due to the increased proportion of expensive sheets in the furniture assembly.

[0045] In particular, the content of polyphosphonate in the core layer and the surface layer varies depending on the product thickness, and preferably satisfies the following formula 1.

[0046] (Equation 1)

[0047] 2.56 ≤ Total thickness of decorative sheet (mm) × Polyphosphonate content (wt%) ≤ 2.58

[0048] For example, if the product thickness is 0.60 mm, the core layer 10 preferably contains 4.3% by weight of polyphosphonate relative to the total weight of the core layer 10; if the product thickness is 0.20 mm, the core layer 10 preferably contains 12.8% by weight of polyphosphonate relative to the total weight of the core layer 10.

[0049] Additionally, for example, if the product thickness is 0.60 mm, the surface layer 20 preferably contains 4.3% by weight of polyphosphonate relative to the total weight of the surface layer 20, and if the product thickness is 0.20 mm, the surface layer 20 preferably contains 12.8% by weight of polyphosphonate relative to the total weight of the surface layer 20.

[0050] At this point, if the value of Equation 1 exceeds 2.58 (excessive polyphosphonate content), the tensile strength decreases; if the value of Equation 1 is less than 2.56 (insufficient polyphosphonate content), the flame retardant performance is insufficient.

[0051] Preferably, the core layer 10 and the surface layer 20 further include a masterbatch made of colored dyes or pigments and polyester resin. More preferably, the masterbatch content of the surface layer 20 is greater than that of the core layer 10. In this case, the masterbatch is formed by mixing 10 to 50 parts by weight of colored dyes or pigments with 100 parts by weight of polyester.

[0052] More specifically, the core layer 10 preferably contains 4% to 12% by weight of color masterbatch relative to the total weight of the core layer 10, and the surface layer 20 preferably contains 25% to 35% by weight of color masterbatch relative to the total weight of the surface layer 20.

[0053] If the color masterbatch content of the core layer 10 is less than 4% by weight, there will be insufficient shielding of the product. If the color masterbatch content of the core layer 10 exceeds 12% by weight, it will become the main factor increasing the cost.

[0054] In addition, if the color masterbatch content of the surface layer 10 is less than 25% by weight, there will be a color difference problem caused by the color of polyphosphonate. If the color masterbatch content of the surface layer 10 is greater than 35% by weight, there will be a problem of reduced adhesion when it is attached to wood due to the decrease in PET-G content in the surface layer.

[0055] The flame-retardant polyester decorative sheet according to an embodiment of the present invention contains a fuel or pigment for imparting shielding and coloring properties to the decorative sheet, and may include at least one dye or pigment selected from the group consisting of white, black, red, yellow, green, blue and purple.

[0056] As pigments that can be used in this invention, any inorganic or organic pigment known to those skilled in the art can be used without limitation, as long as they do not decompose during the preparation of the masterbatch, resulting in poor coloring or appearance. For example, as a conventional white pigment, inorganic particles such as titanium dioxide, calcium carbonate, barium sulfate, magnesium carbonate, kaolin, silica, clay, calcium terephthalate, alumina, and calcium phosphate can be used. When melt-mixed with copolyester resin, fine particles of insoluble high-melting-point organic compounds, fine particles of cross-linked polymers, and internal particles formed within the polymer during the preparation of copolyester using metal compound catalysts used in the synthesis of polyester, such as alkali metal compounds and alkaline earth metal compounds, can be used. In addition, carbon black is widely used as a black pigment. Furthermore, red, yellow, green, blue, or purple pigments, which are the basic colors of the Munsell color system, can be selected and used from the range of pigments known to those skilled in the art.

[0057] In one embodiment, the protective coating 30 is formed by coating it onto the surface of the surface layer 20, and includes a phosphorus-based flame retardant (ammonium polyphosphate) and a UV-curable resin (aliphatic urethane acrylate, etc.). The protective coating 30 is formed by coating the surface layer 20 with a hard coating solution in which a phosphorus-based flame retardant is mixed in a UV-curable resin, drying it, and then curing it using a UV curing method.

[0058] In one embodiment, the thickness ratio (core layer thickness / surface layer thickness) of the core layer 10 to the surface layer 20 is preferably 5 to 7. If the thickness ratio is less than 5, there is an increase in cost; if the thickness ratio is greater than 7, it is difficult to prevent the core layer from discoloring due to insufficient surface layer.

[0059] The phosphorus (P) content of the flame-retardant polyester decorative sheet according to an embodiment of the present invention is preferably 4,000 ppm to 15,000 ppm. The appropriate amount of phosphorus added varies depending on the thickness and is determined by the content of polyphosphonate. The average phosphorus content of polyphosphonate is 10.75%, and the phosphorus content can be appropriately adjusted for each thickness by adjusting the amount of polyphosphonate added during the preparation of the flame-retardant decorative sheet. At this point, if the phosphorus content is below 4,000 ppm, there is a problem of insufficient flame-retardant performance; if the phosphorus content exceeds 15,000 ppm, there are problems of cost, difficulty in extruding the sheet due to reduced viscosity, and damage during cutting due to decreased tensile strength.

[0060] Preferably, the flame-retardant polyester decorative sheet according to an embodiment of the present invention has a color difference value dE difference of less than 0.5 compared with a non-flame-retardant general-purpose decorative sheet of the same color. If the color difference value dE difference exceeds 0.5, it is determined that the colors are inconsistent and it is difficult to use them in parallel or interchangeably.

[0061] Furthermore, compared to non-flame-retardant polyester decorative sheets of the same thickness, the tensile strength ratio of the flame-retardant polyester decorative sheet according to Formula 2 according to an embodiment of the present invention is preferably 0.7 to 1. If the tensile strength ratio according to Formula 2 is 0.7 or higher, the changes in physical properties such as tensile strength differences or color difference standards caused by the use of flame retardants become too large.

[0062] (Equation 2)

[0063] Tensile strength ratio = Tensile strength of flame-retardant polyester decorative sheet / Tensile strength of decorative sheet without added polyphosphonate.

[0064] Figure 2 A flowchart illustrating a method for preparing a flame-retardant polyester decorative sheet according to an embodiment of the present invention.

[0065] Reference Figure 2 According to an embodiment of the present invention, a method for preparing a flame-retardant polyester decorative sheet includes: a first step (S101) of adding raw materials for the core layer and raw materials for the surface layer to a melt extruder respectively; a second step (S102) of extruding the two components under a predetermined extrusion barrel temperature condition using the respective melt extruders; a third step (S103) of forming a sheet structure with a layered structure from the two components that are respectively melt-extruded; and a fourth step (S104) of cooling the sheet by passing it through a cooling roller. The method may also include a fifth step of forming a protective coating by coating the surface of the surface layer with a hard coating solution.

[0066] First, in the first step (S101), where the raw materials for the core layer and the surface layer are added separately to the melt extruders, the raw materials formed by mixing the polyester resin and polyphosphonate that constitute the core layer and the surface layer are added to different melt extruders. At this point, in addition to the polyester resin and polyphosphonate, different amounts of color masterbatch can be added to prepare the raw materials for the core layer and the surface layer; alternatively, the raw materials for the core layer and the surface layer can be prepared by mixing a masterbatch based on a polyester resin including colored dyes or pigments, polyphosphonate, and polyester raw materials.

[0067] Secondly, the second step (S102) of extruding with each melt extruder under predetermined extrusion cylinder temperature conditions is the step of extruding the raw materials of the core layer and the raw materials of the surface layer under predetermined temperature conditions.

[0068] Next, the third step (S103) of forming a sheet structure of layered structure from the two components that are melt-extruded separately is a step of preparing a sheet structure in the form of surface layer / core layer or surface layer / core layer / surface layer by extruding through different channels of a feed block and a T-die or a T-die that connects multiple layers to form a sheet structure of layered structure from the two components that are melt-extruded separately.

[0069] Finally, a flame-retardant polyester decorative sheet according to an embodiment of the present invention is prepared by a fourth step (S104) of cooling by cooling rollers.

[0070] The present disclosure will be described in more detail below by way of examples. These examples are intended to illustrate the present specification in more detail, and the scope of the present disclosure is not limited to the examples described.

[0071] [Example]

[0072] [Example 1]

[0073] A core layer material and a surface layer material, comprising 50 parts by weight of a pigment composed of TiO2 and 50 parts by weight of polyester resin, a polyphosphonate as a flame retardant, and polyester virgin material, are respectively added to a melt extruder for the core layer and a melt extruder for the surface layer. The material combinations added to the melt extruders for the core layer and the surface layer are shown in Table 1.

[0074] Secondly, the core layer material and the surface layer material are extruded separately under the extrusion cylinder temperature of 270℃. In order to make the two melt-extruded components into a layered sheet structure, a decorative sheet with a thickness of 0.40mm with a surface / core / surface structure is prepared by passing through a three-layer flow path, passing through a T-die, and being cooled by a cooling roller.

[0075] Next, a hard coating solution including a phosphorus flame retardant (ammonium polyphosphate) and a UV-curable resin (aliphatic urethane acrylate) is applied to one surface of the prepared sheet, and then dried and cured by a UV curing method to form a protective coating to prepare a flame-retardant polyester decorative sheet.

[0076] [Example 2]

[0077] Except that no protective coating is formed, flame-retardant polyester decorative sheets are prepared in the same manner as in Example 1.

[0078] [Example 3]

[0079] Except for setting the thickness of the decorative sheet to 0.20 mm and changing the core and surface layer contents as shown in Table 1, the flame-retardant polyester decorative sheet was prepared in the same manner as in Example 2.

[0080] [Example 4]

[0081] Except for setting the thickness of the decorative sheet to 0.60 mm and changing the core and surface layer contents as shown in Table 1, the flame-retardant polyester decorative sheet was prepared in the same manner as in Example 2.

[0082] Table 1

[0083]

[0084] [Comparative Example]

[0085] [Comparative Example 1]

[0086] Except for changing the core and surface content as shown in Table 2, flame-retardant polyester decorative sheets were prepared in the same manner as in Example 1.

[0087] [Comparative Example 2]

[0088] Except for changing the core and surface content as shown in Table 2, flame-retardant polyester decorative sheets were prepared in the same manner as in Example 1.

[0089] [Comparative Example 3]

[0090] Except for changing the core and surface content as shown in Table 2, flame-retardant polyester decorative sheets were prepared in the same manner as in Example 1.

[0091] [Comparative Example 4]

[0092] Except for changing the core and surface content as shown in Table 2, flame-retardant polyester decorative sheets were prepared in the same manner as in Example 2.

[0093] [Comparative Example 5]

[0094] Except for changing the thickness of the decorative sheet and the content of the core and surface layers as shown in Table 2, flame-retardant polyester decorative sheets were prepared in the same manner as in Example 2.

[0095] [Comparative Example 6]

[0096] Except for changing the thickness of the decorative sheet and the content of the core and surface layers as shown in Table 2, flame-retardant polyester decorative sheets were prepared in the same manner as in Example 2.

[0097] [Comparative Example 7]

[0098] Except for changing the thickness of the decorative sheet and the content of the core and surface layers as shown in Table 2, flame-retardant polyester decorative sheets were prepared in the same manner as in Example 2.

[0099] [Comparative Example 8]

[0100] Except for changing the thickness of the decorative sheet and the content of the core and surface layers as shown in Table 2, flame-retardant polyester decorative sheets were prepared in the same manner as in Example 2.

[0101] Table 2

[0102]

[0103] The physical properties of the decorative sheets prepared in Examples 1 to 4 and Comparative Examples 1 to 8 were evaluated through the following experimental examples, and the results are shown in Tables 3 and 4.

[0104] [Experimental Example]

[0105] (1) 45-degree combustion test

[0106] To confirm whether the flame retardant performance meets the standards of the Korean Fire Services Agency Announcement No. 2019-2, the flame retardant performance testing rules of the Korean Fire Industry Technology Institute (KFI) were followed, and the afterflame time, smoldering time, damaged area, damaged length, and number of flame exposures were measured based on a 45° burning test (tilt method). The same sample was tested three times, and measurements were taken for each test.

[0107] (2) Color difference measurement

[0108] The color values ​​L, a, b, and color difference dE were determined using a D65 light source and a CM-2500d (Konica Minolta) according to ASTM E1164 standard.

[0109] Furthermore, the color difference value dE* between the target data (comparative example 1) and the target data (not using polyphosphonate) was calculated.

[0110] (3) Transmittance measurement

[0111] The total transmittance was measured on the upper part of the surface using a COH-400 (Nippon Denshoku Kogyo Co., Ltd.).

[0112] (4) Phosphorus content determination

[0113] The phosphorus content of the prepared decorative sheets was determined using NMR spectroscopy.

[0114] (5) Tensile strength

[0115] Tensile strength was determined according to ISO 527 method.

[0116] Table 3

[0117]

[0118] It is evident that Example 1 of the present invention, compared with Comparative Example 1 (which does not use polyphosphonate), Comparative Example 2 (which uses polyphosphonate only in the core layer), and Comparative Example 3 (which uses polyphosphonate only in the surface layer), exhibits superior results in terms of afterflame time, smoldering time, damaged area, and damaged length, and meets the flame retardant performance standards of Korean Fire Services Department Announcement No. 2019-2. Conversely, it is evident that Comparative Examples 1 to 3 do not meet the flame retardant performance standards of Korean Fire Services Department Announcement No. 2019-2. Therefore, the flame-retardant polyester decorative sheet of the present invention, by containing predetermined polyphosphonate in both the surface layer and the core layer, can meet the flame retardant performance standards of Korean Fire Services Department Announcement No. 2019-2.

[0119] Table 4

[0120]

[0121] It can be seen that Examples 2 to 4 according to an embodiment of the present invention satisfy the color difference conditions, phosphorus content, and tensile strength. Furthermore, when comparing Examples 2 to 4 with Comparative Example 1, which is a decorative sheet without added polyphosphonate, it can be confirmed that Examples 2 to 4 have a color difference value difference dE* of 0.5 or less compared to Comparative Example 1. Additionally, compared to Comparative Example 1, Examples 2 to 4 satisfy a tensile strength ratio of 0.7 to 1 according to Formula 2 below. It can be seen that even with the use of polyphosphonate as a flame retardant, the differences in color difference specifications and tensile strength are very small compared to decorative sheets without polyphosphonate.

[0122] (Equation 2)

[0123] Tensile strength ratio = Tensile strength of flame-retardant polyester decorative sheet / Tensile strength of decorative sheet without added polyphosphonate.

[0124] On the other hand, it can be seen that in Comparative Example 4, where the content of color masterbatch in the surface layer and the core layer is the same, the color difference value dE* exceeds 0.5, and discoloration occurs.

[0125] It can be seen that Comparative Example 5, which has an excessive amount of polyphosphonate, has insufficient tensile strength, while Comparative Example 6, which has insufficient polyphosphonate, has insufficient phosphorus content, resulting in insufficient flame retardant performance.

[0126] It is evident that Comparative Example 7, with excessive color masterbatch, suffers from insufficient tensile strength and unnecessary cost increases, while Comparative Example 8, with insufficient color masterbatch, suffers from a color difference value dE* exceeding 0.5.

[0127] As described above, the flame-retardant polyester decorative sheet according to an embodiment of the present invention has a laminated structure of a surface layer and a core layer, and a polyphosphonate flame retardant is used in each layer to provide a decorative sheet with flame-retardant properties. The provided decorative sheet meets the flame-retardant performance standards of Korean Fire Services Agency Announcement No. 2019-2. Furthermore, it is understood that, in order to maintain the same hue deviation as the product without flame retardant, as shown by the color difference value difference dE* described above, the flame-retardant polyester decorative sheet according to an embodiment of the present invention adds a different amount of color masterbatch than that in the core layer and the surface layer to prevent discoloration.

[0128] While preferred embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto. Those skilled in the art will understand that various modifications and improvements can be made without departing from the basic concept of the present disclosure as defined in the appended claims, and such modifications and improvements also fall within the scope of the present disclosure.

Claims

1. A flame-retardant polyester decorative sheet, characterized in that, include: The core layer contains polyester resin and polyphosphonate; and The outer layer, located on at least one side of the core layer, contains polyester resin and polyphosphonate. The thickness of the aforementioned flame-retardant polyester decorative sheet ranges from 0.20 mm to 0.60 mm. The polyphosphonate content of the core layer and the surface layer above satisfies Equation 1: (Equation 1) 2.56 ≤ Total thickness of decorative sheet (mm) × Polyphosphonate content (wt%) ≤ 2.58 The aforementioned core layer and the aforementioned surface layer also include a color masterbatch, which is formed by mixing 10 to 50 parts by weight of colored dye or pigment with 100 parts by weight of polyester resin. The core layer comprises 4% to 12% of the aforementioned masterbatch relative to the total weight of the core layer, and the surface layer comprises 25% to 35% of the aforementioned masterbatch relative to the total weight of the surface layer.

2. The flame-retardant polyester decorative sheet according to claim 1, characterized in that, It also includes a protective coating, which is located on the surface of the surface layer and contains a phosphorus-based flame retardant.

3. The flame-retardant polyester decorative sheet according to claim 1, characterized in that, The phosphorus content of the above flame-retardant polyester decorative sheets is 4,000 ppm to 15,000 ppm.

4. The flame-retardant polyester decorative sheet according to claim 1, characterized in that, Compared with the flame-retardant polyester decorative sheets mentioned above that do not contain polyphosphonate, the color difference value dE* of the flame-retardant polyester decorative sheets mentioned above is less than 0.

5.

5. The flame-retardant polyester decorative sheet according to claim 1, characterized in that, The tensile strength ratio of the above-mentioned flame-retardant polyester decorative sheet according to Formula 2 is 0.7 to 1: (Equation 2) Tensile strength ratio = Tensile strength of flame-retardant polyester decorative sheet / Tensile strength of decorative sheet without added polyphosphonate.

6. The flame-retardant polyester decorative sheet according to claim 1, characterized in that, The content of the masterbatch in the surface layer is greater than the content of the masterbatch in the core layer.

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