A deep-embossed polyester veneer film, a preparation method and a polyester film veneer panel

Abstract

The application discloses a deep-embossed polyester veneer, a preparation method thereof and a polyester film veneer panel. Raw materials of the polyester veneer include 10-20 wt% of flame-retardant polyester and the balance of poly-1,4-cyclohexanedimethylene terephthalate; the flame-retardant polyester is prepared by polycondensation reaction of a first esterification product and a second esterification product in a mass ratio of 60-70:20-30, raw materials of the first esterification product include terephthalic acid and 1,4-cyclohexanedimethanol in a molar ratio of 1:1.05-1.3, and raw materials of the second esterification product include benzoxazine phosphate ester monomer and dihydric alcohol in a molar ratio of 1:1.1-1.3. By introducing a benzoxazine phosphate ester segment in PCT, the flame-retardant property of the polyester veneer is significantly improved without maintaining the mechanical property and processing property of the polyester material.

Description

Technical Field

[0001] This application relates to the field of building materials, and in particular to a deep-embossed polyester decorative film, its preparation method, and polyester film decorative panels. Background Technology

[0002] Polyethylene terephthalate (PET) veneer materials have become a mainstream choice for upscale home furnishings due to their excellent environmental friendliness, smooth surface, and chemical resistance. Through high-gloss or skin-like finishes, PET veneer films can present a delicate two-dimensional visual effect, meeting the minimalist aesthetic demands of modern homes. However, PET material has a lower heat distortion temperature than the temperature window required for hot pressing. During high-temperature hot pressing, PET veneer films are prone to softening and deformation, leading to blurred embossing and even damage to the substrate. This has prevented PET eco-boards from achieving deep, three-dimensional embossing designs for a long time, limiting the product's competitiveness in the high-end customized home furnishing market.

[0003] To overcome thermal performance limitations, polyethylene terephthalate (PCT) has been introduced into the finishing industry due to its higher glass transition temperature. PCT finishing films maintain structural stability under hot-pressing conditions of 160-200℃, successfully solving the thermal deformation problem in deep embossing processes and enabling precise transfer of complex three-dimensional textures. However, like most polyesters, PCT is flammable and struggles to meet the increasingly stringent flame-retardant safety standards in the construction and furniture industries. Existing technologies typically improve flame retardancy by adding large amounts of flame retardants (such as aluminum hydroxide and ammonium polyphosphate), but high filler content leads to a decrease in the mechanical properties and surface abrasion resistance of the finishing film. More seriously, flame retardant particles hinder texture formation during hot pressing, causing a decrease in embossing clarity and negating the deep embossing advantages of PCT. Summary of the Invention

[0004] To address the current problem that deep-embossed polyester films cannot simultaneously achieve flame retardant properties, mechanical properties, and appearance properties, this application provides a deep-embossed polyester decorative film, its preparation method, and a polyester film decorative sheet.

[0005] In a first aspect, this application provides a deeply embossed polyester decorative film, wherein the raw material of the polyester decorative film comprises 10-20 wt% flame-retardant polyester, and the balance is polyethylene terephthalate (PET). The flame-retardant polyester is obtained by polycondensation reaction of a first esterification product and a second esterification product in a mass ratio of 60-70:20-30. The raw material of the first esterification product comprises terephthalic acid and PET in a molar ratio of 1:1.05-1.3, and the raw material of the second esterification product comprises benzoxazine phosphate monomer and diol in a molar ratio of 1:1.1-1.3.

[0006] In any of the above technical solutions, the benzoxazine phosphate monomer is prepared by a substitution reaction of vanillic acid-ethanolamine benzoxazine and phenylphosphodichloro in a molar ratio of 2 to 2.1:1; the vanillic acid-ethanolamine benzoxazine is prepared by a Mannich reaction of vanillic acid, ethanolamine and paraformaldehyde in a molar ratio of 1:1 to 1.2:2 to 2.2.

[0007]

[0008] The synthesis method of benzoxazine phosphate monomer is shown in the above formula, and the specific preparation method is as follows: Ethanolamine and paraformaldehyde were mixed and dissolved in dioxane, vanillic acid was added dropwise, and the reaction was carried out at 70-90°C. After the reaction was completed, the solvent was removed by rotary evaporation, and the residue was recrystallized from ethanol to obtain vanillic acid-ethanolamine benzoxazine monomer. Vanillic acid-ethanolamine benzoxazine monomer and triethylamine acid binder were dissolved in dry N,N-dimethylformamide, and phenylphosphodichloro was added dropwise. The reaction was carried out in an ice-water bath for 0.5 to 1 hour, and then at room temperature for 20 to 30 hours. After the reaction was completed, the solvent was removed by rotary evaporation, and the residue was dissolved in dioxane. The resulting solution was added to ethyl acetate and stirred to precipitate the product, thus obtaining benzoxazine phosphate monomer.

[0009] In any of the above technical solutions, the duration of the Mannich reaction is 22 to 26 hours.

[0010] In any of the above technical solutions, the molar ratio of vanillic acid-ethanolamine benzoxazine monomer and triethylamine is 1:1.1 to 1.2.

[0011] In any of the above technical solutions, the diol is selected from ethylene glycol, propylene glycol, butanediol, or pentanediol.

[0012] In any of the above technical solutions, the method for preparing the flame-retardant polyester is as follows: Terephthalic acid and 1,4-cyclohexanediethanol were mixed and esterified under nitrogen protection at 230–250 °C and 0.3–0.5 MPa until the water content reached more than 95% of the theoretical value, thus obtaining the first esterified product. The benzoxazine phosphate monomer and diol were mixed and esterified at a temperature of 200-230℃ and a pressure of 0.2-0.3MPa until the water content reached more than 95% of the theoretical value, thus obtaining the second esterified product. The first esterification product and the second esterification product are mixed and subjected to low-vacuum reverse polycondensation for 1 to 2 hours at a temperature of 260 to 270°C and a pressure of 1 to 5 kPa. The temperature is then raised to 275 to 285°C and the pressure is reduced to 50 to 70 Pa. High-vacuum polycondensation is then carried out for 2 to 4 hours to obtain the final product.

[0013] In any of the above technical solutions, the esterification reaction time of terephthalic acid and 1,4-cyclohexanediethanol is 3 to 4 hours.

[0014] In any of the above technical solutions, the esterification reaction time of the benzoxazine phosphate monomer and the diol is 2-3 hours.

[0015] In any of the above technical solutions, a catalyst is added to the esterification reaction, preferably titanium glycol.

[0016] In any of the above technical solutions, the polycondensation reaction is accompanied by a catalyst, preferably an antimony-based catalyst and / or a titanium-based catalyst.

[0017] For example, the antimony-based catalyst is antimony trioxide, antimony glycolate, or antimony acetate.

[0018] For example, the titanium-based catalyst is tetrabutyl titanate or titanium glycol.

[0019] This application presents a deep-embossed polyester decorative film using a flame-retardant polyester / PCT composite system. While maintaining the high heat resistance of PCT and achieving deep embossing of the polyester decorative film, it significantly improves flame retardancy and avoids mechanical property degradation. The key lies in the molecular design of the flame-retardant polyester. Specifically, the first esterification product has a highly similar main-chain chemical structure to the PCT matrix, ensuring compatibility and avoiding mechanical property degradation or surface defects caused by phase separation. The second esterification product is precisely introduced into the polyester chain through the polycondensation of benzoxazine phosphate monomer and diol, introducing phosphorus-nitrogen synergistic flame-retardant units. The benzoxazine ring provides gas-phase flame retardancy, while the phosphate promotes char formation, effectively improving the limiting oxygen index (LOI) of the flame-retardant polyester. Because the flame-retardant elements are chemically bonded into the molecular chain, compared to traditional methods of physically blending inorganic flame retardants, tensile strength and surface abrasion resistance are not significantly reduced, effectively solving the problem of reduced mechanical properties and embossing clarity caused by high-filler flame retardant levels.

[0020] Secondly, this application provides a method for preparing a deep-embossed polyester decorative film, wherein flame-retardant polyester and poly(1,4-cyclohexanediethanol terephthalate) are mixed according to the raw material ratio of any of the deep-embossed polyester decorative films, melted at 240-270°C, and the melt is extruded, biaxially stretched to a fixed thickness, and cooled.

[0021] In any of the above technical solutions, after cooling, the polyester decorative film is immersed in a transition metal ion solution at 60-80°C for 2-4 hours; after removal, it is rinsed with deionized water and dried to obtain the final product.

[0022] In any of the above technical solutions, the concentration of the transition metal ion solution is 0.1–0.3 mol / L.

[0023] In any of the above technical solutions, the transition metal ion is selected from Cu. 2+ Zn 2+ or Ni 2+ .

[0024] In any of the above technical solutions, the longitudinal stretching ratio of the biaxial stretching is 2.8 to 3.1, and the transverse stretching ratio is 3.0 to 3.4.

[0025] In any of the above technical solutions, the raw materials of the first esterification product include terephthalic acid, pyridinyl dicarboxylic acid and 1,4-cyclohexanediethanol in a molar ratio of 1:0.1-0.2:1.05-1.1.

[0026] In any of the above technical solutions, the pyridyl dicarboxylic acid is selected from pyridyl dicarboxylic acid and pyridyl terephthalic acid.

[0027] For example, the pyridyldicarboxylic acid is 2,5-pyridyldicarboxylic acid, 3,5-pyridyldicarboxylic acid, 2,6-pyridyldicarboxylic acid, or 2,4-pyridyldicarboxylic acid.

[0028] For example, the pyridyl terephthalic acid is 2-(4-pyridine)terephthalic acid.

[0029] The process of immersing the film in a transition metal ion solution fully utilizes the intermolecular gaps in the amorphous region of the polyester film and the coordination activity of the benzoxazine phosphate groups. Metal ions diffuse and penetrate through the amorphous region, reacting with coordination sites such as the oxygen atoms of the phosphate ester or the nitrogen atoms of the benzoxazine ring in the polyester chain to form a stable chelate structure. On one hand, this structure can catalyze the breaking of ester bonds and promote the formation of a dense carbon layer during combustion, thus increasing the LOI value. On the other hand, the coordination bonds enhance the intermolecular forces in the amorphous region, increasing the elastic modulus of the film, compensating for its mechanical properties, and reducing chain slippage during hot pressing, ensuring the accuracy of deep embossing transfer.

[0030] Furthermore, when a pyridyl dicarboxylic acid is introduced into the first esterification product, its pyridine nitrogen atom has a significantly stronger coordination ability with metal ions than the benzoxazine ring, and can form a bidentate coordination network with the phosphate ester group. This multiple coordination not only improves complexation stability but also inhibits metal ion migration during the hot-pressing stage, reducing flame retardant efficiency or mechanical property loss.

[0031] Thirdly, this application provides a polyester film facing sheet, comprising a substrate, an impregnated adhesive film paper, a hot melt adhesive backing film, and any of the polyester facing films described above or a polyester facing film prepared by any of the preparation methods described above, stacked sequentially.

[0032] The thickness of the deep embossed polyester decorative film in this application can be adjusted according to the actual embossing depth, preferably 0.08 to 0.5 mm.

[0033] In any of the above technical solutions, the hot melt adhesive layer is a reactive polyurethane hot melt adhesive layer.

[0034] In any of the above technical solutions, the reactive polyurethane hot melt adhesive is a blocked isocyanate polyurethane adhesive.

[0035] In any of the above technical solutions, the impregnated film paper is decorative paper impregnated with melamine-formaldehyde resin.

[0036] In any of the above technical solutions, the basis weight of the impregnated film paper is 80-90 g / m². 2 .

[0037] In any of the above technical solutions, the substrate is an ENF-grade engineered wood panel, preferably a plywood core, blockboard core, particleboard core, or oriented strand board core.

[0038] In any of the above technical solutions, the preparation method of the polyester film facing sheet is as follows: Adhesive coating: Apply 30±10g / m² of adhesive coating to one side of the polyester decorative film. 2 The hot melt adhesive is used to form a hot melt backing layer, thus obtaining an adhesive-backed polyester film.

[0039] Substrate sanding: The substrate blank is sanded to a fixed thickness; Composite hot pressing: Impregnated paper and adhesive polyester film are placed sequentially on the surface of the substrate, so that the hot melt adhesive layer of the adhesive polyester film is bonded to the impregnated paper, and hot pressing is performed for 50 to 55 seconds under a unit pressure of 3.0 to 4.0 MPa and a temperature of 180 to 185℃. Curing: Place the hot-pressed boards in a dry, well-ventilated area, stack them neatly, and allow internal stress to fully release. Use a first-in, first-out approach, and cure for at least 3 days to ensure the flatness and dimensional stability of the boards. Trim the edges only after the boards have cooled completely. Trimming: The sanded substrate is cut into finished specifications, generally 1220*2440mm, with square, straight, smooth corners and no obvious saw marks, burnt edges, burrs or other defects.

[0040] In summary, this application has the following beneficial effects: This application utilizes a blend of flame-retardant polyester and PCT to significantly improve the flame retardant properties (LOI) and mechanical properties (tensile strength) of polyester decorative films at low addition levels, while maintaining the clarity of deep embossing. The transition metal ion impregnation process further enhances flame retardancy and mechanical strength through coordination complexation, and the introduction of pyridine segments strengthens coordination stability. When applied to panels, the resulting decorative panels possess both high-value-added three-dimensional textures and high flame retardant properties, breaking through the market technology barriers of traditional two-dimensional decorative furniture panels. Detailed Implementation

[0041] Preparation Example

[0042] Preparation Example 1-1, benzoxazine phosphate monomer, was prepared according to the following steps: Step 1: Add 1.0 mol ethanolamine and 2.2 mol paraformaldehyde to 500 mL of dioxane and stir to dissolve. Add 1.0 mol vanillic acid dropwise, and react at 80 °C for 24 hours under nitrogen protection. After the reaction is complete, remove dioxane by rotary evaporation. Recrystallize the residue three times with ethanol to obtain a white powder of vanillic acid-ethanolamine benzoxazine (VE).

[0043] Step 2: Dissolve 1.0 mol vanillic acid-ethanolamine benzoxazine and 1.2 mol triethylamine in dry N,N-dimethylformamide (1.5 L) and stir in an ice-water bath. Slowly add 1.0 mol phenylphosphodichlorophenate dropwise. After the addition is complete, react in an ice-water bath for 0.5 hours, then heat to 25°C and react for 24 hours. Remove DMF by rotary evaporation. Dissolve the residue in 200 mL of dioxane and pour into 2 L of ethyl acetate to precipitate, thus obtaining the benzoxazine phosphate monomer (VE-BPOD).

[0044] Preparation Examples 1-2: Benzoxazine phosphate monomers were prepared according to the following steps: Step 1: Add 1.0 mol ethanolamine and 2.0 mol paraformaldehyde to 500 mL of dioxane and stir to dissolve. Add 1.0 mol vanillic acid dropwise, and react at 70 °C for 26 hours under nitrogen protection. After the reaction is complete, remove dioxane by rotary evaporation. Recrystallize the residue three times with ethanol to obtain a white powder of vanillic acid-ethanolamine benzoxazine (VE).

[0045] Step 2: Dissolve 1.0 mol vanillic acid-ethanolamine benzoxazine and 1.1 mol triethylamine in dry N,N-dimethylformamide (1.5 L) and stir in an ice-water bath. Slowly add 1.0 mol phenylphosphodichlorophenate dropwise. After the addition is complete, react in an ice-water bath for 1 hour, then raise the temperature to 25°C and react for 22 hours. Remove DMF by rotary evaporation. Dissolve the residue in 200 mL of dioxane and pour into 2 L of ethyl acetate to precipitate, thus obtaining the benzoxazine phosphate monomer (VE-BPOD).

[0046] Preparation Examples 1-3: benzoxazine phosphate monomers were prepared according to the following steps: Step 1: Add 1.0 mol ethanolamine and 2.4 mol paraformaldehyde to 600 mL of dioxane and stir to dissolve. Add 1.0 mol vanillic acid dropwise, and react at 90 °C for 22 hours under nitrogen protection. After the reaction is complete, remove dioxane by rotary evaporation. Recrystallize the residue three times with ethanol to obtain a white powder of vanillic acid-ethanolamine benzoxazine (VE).

[0047] Step 2: Dissolve 1.0 mol vanillic acid-ethanolamine benzoxazine and 1.2 mol triethylamine in dry N,N-dimethylformamide (1.5 L) and stir in an ice-water bath. Slowly add 1.0 mol phenylphosphodichlorophenate dropwise. After the addition is complete, react in an ice bath for 0.5 hours, then heat to 25°C and react for 28 hours. Remove DMF by rotary evaporation. Dissolve the residue in 200 mL of dioxane and pour into 2 L of ethyl acetate to precipitate, thus obtaining the benzoxazine phosphate monomer (VE-BPOD).

[0048] Preparation Example 2-1, flame-retardant polyester, was prepared according to the following steps: First esterification reaction: A slurry was prepared by mixing 5 mol of terephthalic acid, 0.75 mol of 2,4-pyridinedicarboxylic acid, 6.0 mol of 1,4-cyclohexanediethanol, and 10 ppm of titanium glycol (by mass of terephthalic acid). Esterification was carried out at 245°C for 3.5 hours under nitrogen pressure (absolute pressure 0.35 MPa) until the water content was >95%, yielding the first esterification product.

[0049] Second esterification reaction: 5 mol of benzoxazine phosphate monomer from Preparation Example 1-1, 6 mol of ethylene glycol, and 10 ppm of titanium glycol (by mass) of benzoxazine phosphate monomer were mixed to form a slurry. Esterification was carried out at 215°C for 2.5 hours under nitrogen pressure (absolute pressure 0.25 MPa) until the water content was >95%, yielding the second esterification product.

[0050] Polycondensation reaction: Mix the first esterification product (650g) and the second esterification product (350g), add 0.8g of tetrabutyl titanate, and carry out low vacuum reverse polycondensation for 1.5 hours at a temperature of 265℃ and a pressure of 3kPa; then raise the temperature to 280℃, reduce the pressure to 60Pa, and carry out high vacuum polycondensation for 3 hours to obtain the product.

[0051] Preparation Example 2-2, flame-retardant polyester, was prepared according to the following steps: First esterification reaction: A slurry was prepared by mixing 5 mol of terephthalic acid, 0.5 mol of 2,4-pyridinedicarboxylic acid, 5.5 mol of 1,4-cyclohexanediethanol, and 10 ppm of titanium glycol (by mass of terephthalic acid). Esterification was carried out at 230°C for 4 hours under nitrogen pressure (0.5 MPa absolute pressure) until the water content was >95%, yielding the first esterification product.

[0052] Second esterification reaction: 5 mol of benzoxazine phosphate monomer from Preparation Examples 1-2, 5.5 mol of propylene glycol, and 10 ppm of titanium glycol (by mass of benzoxazine phosphate monomer) were mixed to form a slurry. Esterification was carried out at 200°C for 3 hours under nitrogen pressure (absolute pressure 0.25 MPa) until the water content was >95%, yielding the second esterification product.

[0053] Polycondensation reaction: Mix the first esterification product (600g) and the second esterification product (400g), add 0.5g tetrabutyl titanate, and carry out low vacuum reverse polycondensation for 1.5 hours at a temperature of 260℃ and a pressure of 5kPa; then raise the temperature to 275℃, reduce the pressure to 70Pa, and carry out high vacuum polycondensation for 3.5 hours to obtain the product.

[0054] Preparation Example 2-3, flame-retardant polyester, was prepared according to the following steps: First esterification reaction: A slurry was prepared by mixing 5 mol of terephthalic acid, 1 mol of 2,5-pyridinedicarboxylic acid, 6.5 mol of 1,4-cyclohexanediethanol, and 15 ppm of titanium glycol (by mass of terephthalic acid). Esterification was carried out at 250°C for 3 hours under nitrogen pressure (0.3 MPa absolute pressure) until the water content was >95%, yielding the first esterification product.

[0055] Second esterification reaction: 5 mol of benzoxazine phosphate monomer from Preparation Examples 1-3, 6.3 mol of ethylene glycol, and 15 ppm of titanium glycol (by mass of benzoxazine phosphate monomer) were mixed to form a slurry. Esterification was carried out at 230°C for 2 hours under nitrogen pressure (absolute pressure 0.2 MPa) until the water content was >95%, yielding the second esterification product.

[0056] Polycondensation reaction: Mix the first esterification product (700g) and the second esterification product (300g), add 0.8g tetrabutyl titanate, and carry out low vacuum reverse polycondensation for 1.5 hours at a temperature of 265℃ and a pressure of 3kPa; then raise the temperature to 280℃, reduce the pressure to 60Pa, and carry out high vacuum polycondensation for 3 hours to obtain the product.

[0057] Preparation Examples 2-4, flame-retardant polyesters, differ from Preparation Example 1 in that, in the first esterification reaction, 2,4-pyridinedicarboxylic acid is replaced with equimolar terephthalic acid.

[0058] Preparation Examples 2-5, flame-retardant polyesters, differ from Preparation Example 1 in that, in the second esterification reaction, equimolar terephthalic acid is used to replace the benzoxazine phosphate monomer of Preparation Example 1-1.

[0059] Preparation Examples 2-6, flame-retardant polyesters, differ from Preparation Example 1 in that the second esterification product is replaced with an equal mass of the first esterification product.

[0060] Preparation Examples 2-7, flame-retardant polyesters, differ from Preparation Example 1 in that an equal mass of the second esterification product is used to replace the first esterification product.

[0061] Example

[0062] Example 1: A deeply embossed polyester decorative film was prepared according to the following procedure: Extrusion: 845g of polyethylene terephthalate (PCTG LX100), 150g of the flame-retardant polyester of Preparation Example 2-1, and 5g of silicone powder were fed into a twin-screw extruder (length-to-diameter ratio 48:1) and melt-blended at 255°C. The melt was extruded through a T-die and biaxially stretched with a longitudinal stretch ratio of 3.0 and a transverse stretch ratio of 3.2 to a thickness of 0.15mm. The mixture was then cooled to room temperature to obtain a polyester decorative film.

[0063] Impregnation: Immerse the polyester decorative film in a zinc chloride solution with a concentration of 0.2 mol / L and a temperature of 75°C for 3 hours. After 3 hours, remove the film, rinse it three times with deionized water, and dry it at 50°C for 2 hours to obtain the final product.

[0064] Example 2, a deeply embossed polyester decorative film, is prepared according to the following operation: Extrusion: 795g of polyethylene terephthalate (PCTG LX100), 200g of the flame-retardant polyester of Preparation Example 2-2, and 5g of silicone powder were fed into a twin-screw extruder (length-to-diameter ratio 48:1) and melt-blended at 245°C. The melt was extruded through a T-die and biaxially stretched with a longitudinal stretch ratio of 2.9 and a transverse stretch ratio of 3.1 to a thickness of 0.10mm. The mixture was then cooled to room temperature to obtain a polyester decorative film.

[0065] Impregnation: Immerse the polyester decorative film in a copper chloride solution with a concentration of 0.1 mol / L and a temperature of 80°C for 3 hours. After 3 hours, remove the film, rinse it three times with deionized water, and dry it at 50°C for 2 hours to obtain the final product.

[0066] Example 3, a deeply embossed polyester decorative film, is prepared according to the following operation: Extrusion: 890g of polyethylene terephthalate (PCTG LX100), 100g of the flame-retardant polyester of Preparation Examples 2-3, and 10g of silicone powder were fed into a twin-screw extruder (length-to-diameter ratio 48:1) and melt-blended at 260°C. The melt was extruded through a T-die and biaxially stretched with a longitudinal stretch ratio of 3.1 and a transverse stretch ratio of 3.3 to a thickness of 0.20mm. The mixture was then cooled to room temperature to obtain a polyester decorative film.

[0067] Impregnation: Immerse the polyester decorative film in a zinc chloride solution with a concentration of 0.3 mol / L and a temperature of 70°C for 3 hours. After 3 hours, remove the film, rinse it three times with deionized water, and dry it at 50°C for 2 hours to obtain the final product.

[0068] Example 4: A deep-embossed polyester decorative film, without an impregnation step, is prepared as follows: Extrusion: 845g of poly(1,4-cyclohexanediethanol terephthalate) (PCTG LX100), 150g of the flame-retardant polyester of Preparation Example 2-1, and 5g of silicone powder were fed into a twin-screw extruder (length-to-diameter ratio 48:1) and melt-blended at 255°C. The melt was extruded through a T-die and biaxially stretched with a longitudinal stretch ratio of 3.0 and a transverse stretch ratio of 3.2 to a thickness of 0.15mm. The mixture was then cooled to room temperature to obtain the final product.

[0069] Example 5, a deep-embossed polyester decorative film, differs from Example 1 in that the flame-retardant polyester of Preparation Example 2-1 is replaced with the flame-retardant polyester of Preparation Example 2-4 of equal mass.

[0070] Example 6, a deep-embossed polyester decorative film, differs from Example 4 in that the flame-retardant polyester of Preparation Example 2-1 is replaced with the flame-retardant polyester of Preparation Example 2-4 of equal mass.

[0071] Comparative Example

[0072] Comparative Example 1, a deep-embossed polyester decorative film, differs from Example 1 in that the flame-retardant polyester of Preparation Example 2-1 is replaced with the flame-retardant polyester of Preparation Example 2-5 of equal mass.

[0073] Comparative Example 2, a deep-embossed polyester decorative film, differs from Example 1 in that the flame-retardant polyester of Preparation Example 2-1 is replaced with the flame-retardant polyester of Preparation Example 2-6 of equal mass.

[0074] Comparative Example 3, a deep-embossed polyester decorative film, differs from Example 1 in that the flame-retardant polyester of Preparation Example 2-1 is replaced with the flame-retardant polyester of Preparation Example 2-7.

[0075] Comparative Example 4: A polyester decorative film was prepared according to the following method: 915g of poly(1,4-cyclohexanedimethyl terephthalate) (PCTG LX100), 80g of ammonium polyphosphate, and 5g of silicone powder were fed into a twin-screw extruder (length-to-diameter ratio 48:1) and melt-blended at 255℃. The melt was extruded through a T-die and biaxially stretched with a longitudinal stretch ratio of 3.0 and a transverse stretch ratio of 3.2 to a thickness of 0.15mm. After cooling to room temperature, a polyester decorative film was obtained.

[0076] Application examples

[0077] Application Example 1: A polyester film facing sheet is prepared according to the following steps: Backing coating: A closed-cell isocyanate polyurethane hot melt adhesive is coated onto one side of the deep-embossed polyester decorative film of Example 1, with a coating amount of 30 g / m². 2 The film is cooled and molded to obtain an adhesive-backed polyester film.

[0078] Substrate treatment: ENF grade plywood (1220×2440×18mm) is sanded to a fixed thickness using a 240-mesh sanding belt.

[0079] Composite hot pressing: Place impregnated film paper (85g / m²) sequentially on the surface of the ENF grade plywood after the above treatment. 2 The steel plate is coated with a polyester film and an adhesive-backed polyester film, which is then bonded to the impregnated paper using a hot melt adhesive layer. The coating is then hot-pressed for 50 seconds at a unit pressure of 3.5 MPa and a temperature of 180°C (the steel plate has an embossed wood grain texture with a maximum embossing depth of 0.06 mm).

[0080] Health maintenance: Stacked in a ventilated environment at 25℃ for 4 days, and the flatness is tested after trimming (≤0.3mm / m).

[0081] Application Example 2: A polyester film facing sheet is prepared according to the following steps: Backing coating: A closed-cell isocyanate polyurethane hot melt adhesive is coated onto one side of the deep-embossed polyester decorative film of Example 2, with a coating amount of 40 g / m². 2 The film is cooled and molded to obtain an adhesive-backed polyester film.

[0082] Substrate treatment: ENF grade plywood (1220×2440×18mm) is sanded to a fixed thickness using a 240-mesh sanding belt.

[0083] Composite hot pressing: Place impregnated film paper (85g / m²) sequentially on the surface of the ENF grade plywood after the above treatment. 2 The steel plate is coated with a polyester film and an adhesive-backed polyester film, which is then bonded to the impregnated paper using a hot melt adhesive layer. The coating is then hot-pressed for 55 seconds at a unit pressure of 4 MPa and a temperature of 183°C (the steel plate has a geometric pattern with a maximum embossing depth of 0.04 mm).

[0084] Health maintenance: Stacked in a ventilated environment at 25℃ for 4 days, and the flatness is tested after trimming (≤0.3mm / m).

[0085] Application Examples 3 to 6: A polyester film facing sheet, which differs from Application Example 1 in that an equal amount of the deep embossed polyester facing film obtained in Examples 4 to 7 is used to replace the deep embossed polyester facing film obtained in Example 1.

[0086] Compared with Application Examples 1 to 4, a polyester film facing board is different from Application Example 1 in that the deep embossed polyester facing film obtained in Example 1 is replaced with an equal amount of the deep embossed polyester facing film obtained in Comparative Examples 1 to 4.

[0087] Performance testing Test 1: Flame retardant properties of polyester decorative film The test was conducted according to GB / T 2406.2-2009, "Determination of Combustion Behavior by Oxygen Index Method for Plastics - Part 2: Room Temperature Test". Samples measuring 125mm × 13mm × 3mm were cut from the deeply embossed polyester decorative films of each example and comparative example, with five parallel samples per group. The samples were vertically fixed in the combustion chamber of the oxygen indexer, and a nitrogen-oxygen mixture (flow rate 10 L / min) was introduced. The top of the sample was ignited, and the minimum oxygen concentration (accurate to 0.1%) required for a combustion length of 50mm was recorded. The test was repeated until a stable LOI value was obtained, and the average value was taken.

[0088] Test 2: Tensile strength of polyester decorative film The test was conducted according to ASTM D638-2014, "Standard Test Method for Tensile Properties of Plastics". Dumbbell-shaped specimens were cut along the transverse (TD) direction of the film and tested using an Instron 5567 universal testing machine at a tensile speed of 50 mm / min. The ambient temperature was 23 ± 2 °C and the humidity was 50 ± 5%. The tensile strength (MPa) was recorded.

[0089] Test 3: Abrasion resistance of polyester decorative film The abrasion resistance test was conducted in accordance with Method 1 of Section 4.45 of GB / T 17657-2022 "Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels", and the number of abrasion resistance revolutions was recorded.

[0090] Table 1. Performance test results of tests 1 to 3

[0091] Experiment 4: Deep Embossing Forming Quality The percentage of test panels with poor texture quality (including blurred, missing, collapsed, or deformed textures) in the finished decorative panels of Application Examples 1-6 and Comparative Application Examples 1-4 is recorded as the defect rate (%).

[0092] Table 2. Performance test results of Experiment 4

[0093] Analysis of experimental results: Compared to Example 1, Example 4 (without metal ion solution impregnation) showed a slight decrease in LOI due to the lack of catalytic char formation effect of metal ions, resulting in reduced flame retardant efficiency. Its tensile strength and abrasion resistance decreased due to the absence of coordination bonds in the amorphous region, weakening the intermolecular forces. The embossing defect rate increased due to increased chain segment slippage during hot pressing, leading to slight collapse of the embossing. Example 5 (pyridine-free flame-retardant polyester) showed a slight decrease in LOI due to the deficiency of pyridine groups weakening the bidentate coordination network, reducing metal ion utilization and coordination stability, making it prone to decomposition and failure during combustion. Its tensile strength and abrasion resistance decreased due to insufficient coordination stability, exacerbating surface wear. Example 6 (without metal ion solution impregnation and pyridine-free flame-retardant polyester) showed a further decrease in LOI, tensile strength, and abrasion resistance compared to Examples 4 and 5, confirming the synergistic effect of pyridine groups and metal impregnation.

[0094] Compared to the examples, the LOI of Comparative Example 1 (the second esterification product lacks benzoxazine phosphate segments) and Comparative Example 2 (only the first esterification product) decreased significantly, due to the absence of flame-retardant segments in the polyester matrix, resulting in the complete failure of the phosphorus-nitrogen synergistic flame-retardant mechanism. Comparative Example 3 (only the second esterification product) showed a certain decrease in LOI, and a significant decrease in tensile strength and abrasion resistance, due to the absence of PCT-compatible segments, causing uneven dispersion of the flame retardant. Comparative Example 4 (with the addition of traditional inorganic flame retardants) showed a significantly increased embossing defect rate, due to the clarity degradation caused by the inorganic flame retardant during hot pressing.

[0095] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A deep-embossed polyester finish film, characterized by, The raw material of the polyester decorative film comprises 10-20 wt% flame-retardant polyester, with the balance being polyethylene terephthalate (PET). The flame-retardant polyester is obtained by polycondensation reaction of a first esterification product and a second esterification product in a mass ratio of 65:35, 60:40, or 70:

30. The raw material of the first esterification product comprises terephthalic acid, pyridyl dicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid in a molar ratio of 1:0.1-0.2:1.05-1.

1. 4-Cyclohexanediethanol; the raw material for the second esterification product comprises benzoxazine phosphate monomer and diol in a molar ratio of 1:1.1 to 1.3; the benzoxazine phosphate monomer is prepared by a substitution reaction of vanillic acid-ethanolamine benzoxazine and phenylphosphodichloro in a molar ratio of 1:1; the vanillic acid-ethanolamine benzoxazine is prepared by a Mannich reaction of vanillic acid, ethanolamine and paraformaldehyde in a molar ratio of 1:1 to 1.2:2 to 2.2; The preparation method of the deep embossed polyester decorative film is as follows: Flame-retardant polyester and poly(1,4-cyclohexanediethanol) terephthalate are mixed and melted at 240–270°C. The melt is extruded, biaxially stretched to a fixed thickness, and cooled. The polyester decorative film is then immersed in a transition metal ion solution at 60–80°C for 2–4 hours. After rinsing with deionized water and drying, the final product is obtained.

2. The deep-embossed polyester cover film according to claim 1, characterized in that The preparation method of the benzoxazine phosphate monomer is as follows: Ethanolamine and paraformaldehyde were mixed and dissolved in dioxane, vanillic acid was added dropwise, and the reaction was carried out at 70-90°C. After the reaction was completed, the solvent was removed by rotary evaporation, and the residue was recrystallized from ethanol to obtain vanillic acid-ethanolamine benzoxazine monomer. Vanillic acid-ethanolamine benzoxazine monomer and triethylamine were dissolved in dry N,N-dimethylformamide, and phenylphosphodichloro was added dropwise. The mixture was reacted in an ice-water bath for 0.5 to 1 hour and then at room temperature for 20 to 30 hours. After the reaction was completed, the solvent was removed by rotary evaporation, and the residue was dissolved in dioxane. The resulting solution was added to ethyl acetate and stirred to precipitate the product, thus obtaining the benzoxazine phosphate monomer.

3. The deep-embossed polyester cover film according to claim 2, characterized in that The molar ratio of vanillic acid-ethanolamine benzoxazine monomer and triethylamine is 1:1.1 to 1.

2.

4. The deep-embossed polyester cover film according to claim 1, characterized in that, The diol is selected from ethylene glycol, propylene glycol, butanediol, or pentanediol.

5. The deep-embossed polyester cover film according to claim 1, characterized in that, The method for preparing the flame-retardant polyester is as follows: Terephthalic acid and 1,4-cyclohexanediethanol were mixed and esterified under nitrogen protection at 230–250 °C and 0.3–0.5 MPa until the water content reached more than 95% of the theoretical value, thus obtaining the first esterified product. The benzoxazine phosphate monomer and diol were mixed and esterified at a temperature of 200-230℃ and a pressure of 0.2-0.3MPa until the water content reached more than 95% of the theoretical value, thus obtaining the second esterified product. The first esterification product and the second esterification product are mixed and subjected to low-vacuum reverse polycondensation for 1 to 2 hours at a temperature of 260 to 270°C and a pressure of 1 to 5 kPa. The temperature is then raised to 275 to 285°C and the pressure is reduced to 50 to 70 Pa. High-vacuum polycondensation is then carried out for 2 to 4 hours to obtain the final product.

6. The deep-embossed polyester decorative film according to claim 1, characterized in that, The concentration of the transition metal ion solution is 0.1–0.3 mol / L.

7. A polyester film-faced panel, characterized in that, It includes a substrate, an impregnated paper, a hot-melt adhesive backing film, and a deep-embossed polyester decorative film as described in any one of claims 1 to 6, stacked in sequence.

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