High-temperature-resistant advertising paper, preparation method thereof and high-temperature-resistant polyurethane adhesive

Abstract

The invention relates to the technical field of advertising paper, and particularly discloses high-temperature-resistant advertising paper, a preparation method of the high-temperature-resistant advertising paper and a high-temperature-resistant polyurethane adhesive. The high-temperature-resistant advertising paper comprises an aluminum foil layer and environment-friendly release paper, wherein the aluminum foil layer and the environment-friendly release paper are bonded through a high-temperature-resistant polyurethane adhesive; the high-temperature-resistant polyurethane adhesive is formed by mixing polyurethane resin, an anti-aging agent, a flatting agent, a defoaming agent, a modified inorganic heat-resistant flame retardant and water; the preparation method comprises the following steps: stirring and mixing polyurethane resin and water, adding the anti-aging agent, the flatting agent, the defoaming agent and the modified heat-resistant flame retardant, and stirring and mixing to obtain the high-temperature-resistant polyurethane adhesive. Coating the surface of the aluminum foil layer with a high-temperature-resistant polyurethane adhesive, and arranging environment-friendly release paper, so as to obtain the high-temperature-resistant advertising paper. The high-temperature-resistant advertising paper disclosed by the invention does not deform and yellow after being continuously used for 6 hours at the high temperature of 250 DEG C, can be applied to high-temperature places such as electric heating panels and outdoor wall decorations, and has good high-temperature resistance and flame retardance.

Description

Technical Field

[0001] The present application relates to the technical field of advertising paper, and more specifically, to a high temperature resistant advertising paper and a preparation method thereof and a high temperature resistant polyurethane adhesive. Background Art

[0002] Advertising paper is a kind of paper designed specifically for advertising. There are many types of paper, and each type of paper has its own specific characteristics and uses to meet different advertising needs.

[0003] PVC advertising paper is a classic advertising paper material, which has the characteristics of water resistance, UV resistance, strong flexibility, and not easy to tear. Therefore, PVC advertising paper is often used in scenes such as exhibition boards and light box advertisements.

[0004] Because at higher temperatures, the movement between PVC molecules will accelerate, which may cause polymer chains to break and trigger thermal decomposition. Therefore, when PVC advertising paper is used in high-temperature scenarios such as electric heating panels or outdoor wall decoration materials, it is easy to deform, turn yellow, or even melt, which greatly reduces the aesthetics and durability of the advertisement. Summary of the invention

[0005] In order to improve the high temperature resistance of advertising paper, the present application provides a high temperature resistant advertising paper and a preparation method thereof and a high temperature resistant polyurethane adhesive.

[0006] In the first aspect, the present application provides a high temperature resistant advertising paper, which adopts the following technical solution: A high temperature resistant advertising paper, comprising an aluminum foil layer and an environmentally friendly release paper, wherein the aluminum foil layer and the environmentally friendly release paper are bonded by a high temperature resistant polyurethane adhesive; The high temperature resistant polyurethane adhesive is composed of the following components in percentage by weight: Polyurethane resin 38-45%; Antiaging agent 2-4%; Leveling agent 4-6%; Defoaming agent 1-3%; Modified inorganic heat-resistant flame retardant 3-5; Water 41-50%; The preparation method of the modified inorganic heat-resistant flame retardant comprises the following steps: A1: After stirring and mixing the aminosilane coupling agent and the ethanol aqueous solution, add the mixture of the inorganic heat resistant agent and the inorganic flame retardant, stir and mix to obtain a silane modified mixture; A2: Add chitosan and epoxy resin into the silane modified mixture, stir and mix, and obtain a heat-resistant flame-retardant modifier.

[0007] After hydrolysis, aminosilane coupling agent generates silanol, which can bond with the hydroxyl groups on the surface of inorganic heat-resistant agent and inorganic flame retardant, thereby grafting amino groups on the surface of inorganic heat-resistant agent and inorganic flame retardant. Since chitosan contains a large number of hydroxyl groups and epoxy resin contains a large number of epoxy groups, chitosan and epoxy resin are added to the silane-modified mixture, and the amino groups in the silane-modified mixture can react with the hydroxyl groups in chitosan and the epoxy groups in the epoxy resin to obtain a modified inorganic heat-resistant flame retardant with chitosan and epoxy resin grafted on the surface.

[0008] By adopting the above technical scheme, biocompatible chitosan and heat-resistant epoxy resin are grafted on the surface of the inorganic heat-resistant flame retardant, which can improve the compatibility and dispersibility of the modified inorganic heat-resistant flame retardant in the polyurethane resin, so that the polyurethane adhesive has higher heat resistance and flame retardancy. At the same time, the aluminum foil layer uses forged aluminum foil, which also has good heat resistance. Therefore, the advertising paper made of polyurethane adhesive bonding aluminum foil layer and environmentally friendly isolation paper in this application has good high temperature resistance and flame retardant properties, and does not deform or turn yellow for 6 hours at a high temperature of 250°C. It can be used in high temperature places such as electric heating panels and outdoor wall decorations. The service life can reach 15 years, and there is no safety hazard of easy ignition and flammability during use.

[0009] Preferably, in the preparation method of the modified inorganic heat-resistant flame retardant, the weight ratio of the mixture, aminosilane coupling agent, chitosan, epoxy resin and ethanol aqueous solution is 1:(0.38-0.56):(0.15-0.22):(0.08-0.16):(2-5).

[0010] By adopting the above technical scheme, the modified heat-resistant flame retardant prepared by mixing according to the above weight ratio has a silane coupling agent, chitosan and epoxy resin grafted on the surface, has good hydrophilic and lipophilic properties, is easy to disperse in polyurethane resin, has high compatibility, and can effectively improve the heat resistance and flame retardancy of the prepared adhesive.

[0011] Preferably, in the preparation method of the modified inorganic heat-resistant flame retardant, the weight ratio of the mixture, aminosilane coupling agent, chitosan, epoxy resin and ethanol aqueous solution is 1:(0.40-0.52):0.20:(0.10-0.14):4.

[0012] By adopting the above technical scheme, by increasing the amount of aminosilane coupling agent and epoxy resin, a large amount of aminosilane coupling agent and epoxy resin undergo a ring-opening reaction, a large amount of heat-resistant three-dimensional network structure film layer can be formed on the surface of the modified heat-resistant flame retardant, which is beneficial to improving the heat resistance of the prepared adhesive.

[0013] Preferably, in the preparation method of the modified inorganic heat-resistant flame retardant, the epoxy resin is an alicyclic epoxy resin.

[0014] By adopting the above technical scheme, since the epoxy groups in the alicyclic epoxy resin are directly connected to the alicyclic ring, the three-dimensional network structure formed after the amino and epoxy groups are opened has a larger density, a larger rigid structure, and higher thermal stability, which is beneficial to the heat resistance of the prepared adhesive.

[0015] Preferably, the alicyclic epoxy resin has a viscosity of 300 to 450 cps at 25° C. and an epoxy equivalent of 131 to 143 g / Eq.

[0016] By adopting the above technical scheme, the cyclic epoxy resin with the above performance has a higher glass transition temperature and good processing performance. The film layer formed on the surface of the modified heat-resistant flame retardant has excellent thermal stability, which is beneficial to improving the heat resistance of the prepared adhesive.

[0017] Preferably, in the high temperature resistant polyurethane adhesive, the polyurethane resin is an anionic aliphatic waterborne polyurethane dispersion with a viscosity of 50 to 2000 mPa·s, a pH value of 6 to 8, and a solid content of 44 to 46.

[0018] By adopting the above technical solution, the above anionic aliphatic waterborne polyurethane dispersion has the advantages of fast initial adhesion speed, high bonding strength and high thermal stability, and has high compatibility with raw materials such as modified heat-resistant flame retardants. Therefore, the adhesive prepared using the above anionic aliphatic waterborne polyurethane dispersion as the main raw material has high heat resistance, flame retardancy and bonding properties.

[0019] Preferably, in the high temperature resistant polyurethane adhesive, the inorganic flame retardant is a silver flame retardant.

[0020] By adopting the above technical scheme, the silver flame retardant, especially the silver special flame retardant magnesium hydroxide, which is a high-purity magnesium hydroxide produced by chemical synthesis, has a regular hexagonal flake structure, a narrow particle size distribution, and good single crystal dispersion. It not only has a good flame retardant effect, but is also easy to carry out silane surface treatment.

[0021] In a second aspect, the present application provides a method for preparing high temperature resistant advertising paper, which adopts the following technical solution: A method for preparing high temperature resistant advertising paper comprises the following steps: S1: After the polyurethane resin and water are stirred and mixed at 90-95° C. for 3-4 hours, the mixture is cooled to 30-35° C., an antioxidant, a leveling agent, a defoaming agent and a modified heat-resistant flame retardant are added, and the mixture is stirred and mixed to obtain a high-temperature resistant polyurethane adhesive; S2: coating the surface of the aluminum foil layer with a high-temperature resistant polyurethane adhesive, and then placing an environmentally friendly isolation paper on the side of the aluminum foil layer coated with the high-temperature resistant polyurethane adhesive, thereby obtaining the high-temperature resistant advertising paper.

[0022] By adopting the above technical scheme, the polyurethane resin and water are fully mixed at 90-95°C, which is conducive to the compatibility and dispersion of raw materials such as modified heat-resistant flame retardants in the polyurethane resin aqueous solution, and a polyurethane adhesive in which the modified heat-resistant flame retardant is uniformly dispersed is obtained. The polyurethane adhesive layer formed after curing on the aluminum foil has good high temperature resistance and flame retardant properties.

[0023] In a third aspect, the present application provides a high temperature resistant polyurethane adhesive, which adopts the following technical solution: A high temperature resistant polyurethane adhesive, composed of the following components in percentage by weight: Polyurethane resin 38-45%; Antiaging agent 2-4%; Leveling agent 4-6%; Defoaming agent 1-3%; Modified inorganic heat-resistant flame retardant 3-5; Water 41-50%; The preparation method of the modified inorganic heat-resistant flame retardant comprises the following steps: A1: After stirring and mixing the aminosilane coupling agent and the ethanol aqueous solution, add the mixture of the inorganic heat resistant agent and the inorganic flame retardant, stir and mix to obtain a silane modified mixture; A2: Add chitosan and epoxy resin into the silane modified mixture, stir and mix, and obtain a heat-resistant flame-retardant modifier.

[0024] By adopting the above technical solution, on the one hand, chitosan with good biocompatibility can improve the compatibility of the modified inorganic heat-resistant flame retardant in the polyurethane resin, so that the modified inorganic heat-resistant flame retardant can be evenly dispersed in the polyurethane resin and is not easy to precipitate, which is beneficial to improving the heat resistance and flame retardancy of the prepared adhesive. On the other hand, the three-dimensional network structure formed by the reaction of amino and epoxy resin has high thermal stability and is not easy to decompose, which is beneficial to improving the heat resistance of the prepared adhesive.

[0025] At the same time, epoxy resin has good hydrophobicity. Chitosan and epoxy resin are selected for grafting, and the surface of the modified inorganic heat-resistant flame retardant has both hydrophilic and hydrophobic properties, so that it has good compatibility and dispersibility in polar resins, which can further improve the heat resistance and flame retardancy of the prepared adhesive.

[0026] In summary, this application has the following beneficial effects: 1. Since the aluminum foil and polyurethane adhesive used in this application have good heat resistance, the high-temperature resistant advertising paper prepared by bonding the aluminum foil layer and the environmentally friendly release paper with polyurethane adhesive has excellent high-temperature resistance and can be used in high-temperature places without deformation or yellowing; 2. The preparation method of the high temperature resistant advertising paper in the present application is to fully mix the raw materials in the polyurethane adhesive, apply it on the surface of the aluminum foil, and then set the environmentally friendly isolation paper. The preparation method is simple and suitable for large-scale production; 3. The present application grafts chitosan and epoxy resin on the surface of inorganic heat-resistant agent and inorganic flame retardant. Since chitosan has good biocompatibility and epoxy resin can form a thermally stable three-dimensional network structure after ring-opening reaction, the inorganic heat-resistant flame retardant has good compatibility and dispersibility in polyurethane resin and is not easy to precipitate after curing, which is beneficial to improve the high temperature resistance of polyurethane adhesive after curing. DETAILED DESCRIPTION

[0027] The present application is further described in detail below in conjunction with embodiments.

[0028] The raw materials used in the examples of this application are commercially available except for the following special instructions; Aminosilane coupling agent, 3-aminopropylmethyldimethoxysilane; Ethanol aqueous solution, mass fraction is 75%; Inorganic heat resistant agent, hydrophilic nano-silicon dioxide, content 99.6%, 3000 mesh; Inorganic flame retardant, magnesium hydroxide for silver special flame retardant, magnesium hydroxide content ≥99.0%, silicon oxide content ≤0.1%, acid insoluble matter ≤0.05%, particle size D50<1.5μm, moisture ≤0.5%, chloride ion content ≤0.1%, iron ion content ≤0.005%, specific surface area ≤8m 2 / g, whiteness>97; Chitosan is industrial grade chitosan with a deacetylation degree of 85%, a drying loss of ≤12%, a pH value of 6.5-8.5, and an insoluble matter of ≤2%.

[0029] Preparation Example Preparation Example 1 A modified inorganic heat-resistant flame retardant, the raw materials and their corresponding weights (kg) are shown in the following table.

[0030] The preparation method of the modified inorganic heat-resistant flame retardant comprises the following steps: A1: After the aminosilane coupling agent and the ethanol aqueous solution were stirred and mixed for 20 minutes, a mixture of an inorganic heat resistant agent and an inorganic flame retardant was added, and the mixture was stirred and mixed at 400 r / min for 30 minutes to obtain a silane-modified mixture; A2: chitosan was added to the silane modified mixture, stirred and mixed at 600 r / min for 10 min, and then epoxy resin was added, stirred and mixed for 30 min to obtain a heat-resistant flame retardant modifier.

[0031] In the preparation example of the present application, the epoxy resin brand is Syna-Epoxy 21, the viscosity is 300-450 cps at 25°C, and the epoxy equivalent is 131-143 g / Eq.

[0032] Preparation Examples 2 to 5 A modified inorganic heat-resistant flame retardant, which is different from Preparation Example 1 in that the raw materials and their corresponding weights (kg) are shown in the following table.

[0033] Preparation Example 6 A modified inorganic heat-resistant flame retardant, which is different from Preparation Example 1 in that the epoxy resin brand is Syna-Epoxy 27, the viscosity at 25°C is ≤20cps, and the epoxy equivalent is 105-120g / Eq.

[0034] Preparation Example 7 A modified inorganic heat-resistant flame retardant, which is different from Preparation Example 1 in that the epoxy resin brand is Wuxi Phoenix brand epoxy resin 618, the viscosity is 1000 mPas, and the epoxy equivalent is 184-195 g / Eq.

[0035] Preparation Example 8 A modified inorganic heat-resistant flame retardant, which is different from Preparation Example 1 in that the preparation method of the inorganic heat-resistant flame retardant comprises the following steps: A1: After the aminosilane coupling agent and the ethanol aqueous solution were stirred and mixed for 20 minutes, a mixture of an inorganic heat resistant agent and an inorganic flame retardant was added, and the mixture was stirred and mixed at 400 r / min for 30 minutes to obtain a silane-modified mixture; A2: Add epoxy resin to the silane modified mixture, stir and mix at 600 r / min for 10 minutes, then add chitosan, stir and mix for 30 minutes to obtain a heat-resistant flame retardant modifier.

[0036] Preparation Example 9 A modified inorganic heat-resistant flame retardant, which is different from Preparation Example 1 in that an equal weight of water-based polyamide resin is used to replace the epoxy resin, wherein the water-based polyamide resin is an anionic aliphatic water-based polyurethane dispersion with a viscosity of 50 to 2000 mPa·s, a pH value of 6 to 8, and a solid content of 44 to 46. Example

[0037] Example 1 A high temperature resistant advertising paper comprises an aluminum foil layer and an environmentally friendly release paper, wherein the aluminum foil layer and the environmentally friendly release paper are bonded by a high temperature resistant polyurethane adhesive.

[0038] The components of the above-mentioned high temperature resistant polyurethane adhesive and their corresponding weights (kg) are shown in the following table.

[0039] The method for preparing the above-mentioned high temperature resistant advertising paper comprises the following steps: S1: After the polyurethane resin and water are stirred and mixed at 90-95° C. (90° C. in the present embodiment of the present application) for 3-4 h (4 h in the present embodiment of the present application), the mixture is cooled to 30-35° C., an antioxidant, a leveling agent, a defoaming agent and a modified heat-resistant flame retardant are added, and the mixture is stirred and mixed to obtain a high-temperature resistant polyurethane adhesive; In the present application, the polyurethane resin is PU-645 anionic aliphatic waterborne polyurethane dispersion has a viscosity of 50-2000 mPa·s, a pH value of 6-8, and a solid content of 44-46.

[0040] S2: coating the surface of the aluminum foil layer with a high-temperature resistant polyurethane adhesive, and then placing an environmentally friendly isolation paper on the side of the aluminum foil layer coated with the high-temperature resistant polyurethane adhesive, thereby obtaining the high-temperature resistant advertising paper.

[0041] Embodiment 2-3 A high temperature resistant advertising paper, which is different from Example 1 in that the components of the high temperature resistant polyurethane adhesive and their corresponding weights (kg) are shown in the following table.

[0042] Embodiments 4 to 10 A high temperature resistant advertising paper, which is different from Example 1 in that the modified inorganic heat resistant flame retardant is prepared by the preparation example in the following table.

[0043] Comparative Example Comparative Example 1 A PVC advertising paper is commercially available.

[0044] Comparative Example 2 An advertising paper, which is different from Example 1 in that an inorganic heat-resistant flame retardant of equal weight is used to replace the modified inorganic heat-resistant flame retardant, wherein the inorganic heat-resistant flame retardant is composed of an inorganic heat-resistant agent and an inorganic flame retardant mixed in a weight ratio of 1:1.

[0045] Comparative Example 3 An advertising paper, which is different from Example 1 in that the modified inorganic heat-resistant flame retardant is prepared by Preparation Example 9.

[0046] Performance Testing 1. The high temperature resistant advertising paper prepared in the embodiment of the present application and the PVC advertising paper of comparative example 1 were tested for high temperature resistance. The testing method was as follows: After tearing off the environmentally friendly isolation paper from the high-temperature resistant advertising paper, place it together with the PVC advertising paper in a 250℃ oven for 6 hours to check whether the high-temperature resistant advertising paper or the advertising paper is deformed or yellowed.

[0047] The performance test results are shown in the following table: By analyzing the data in the above table, it can be seen that the high temperature resistant advertising paper prepared in Examples 1 to 11 of the present application does not deform or turn yellow after being placed in a 250°C oven for 6 hours. The PVC advertising paper prepared in Comparative Example 1 deforms and turns yellow after being placed in a 250°C oven for 6 hours. This shows that the high temperature resistant advertising paper prepared in Examples 1 to 11 of the present application has high high temperature resistance and can be used in high temperature places such as electric heating panels and outdoor wall decorations.

[0048] 2. The high temperature resistant polyurethane adhesives prepared in the examples and comparative examples of the present application were tested for shear strength and flame retardancy. The testing methods are as follows: Shear strength: After curing the high temperature resistant polyurethane adhesive at 85℃ / 85%RH for 7 days, put it in a 120℃ oven for 24h, and then test its shear strength in a 120℃ high and low temperature tensile machine; Flame retardant properties: Samples were prepared according to ANSI / UL 94-1985 standard, and the flame retardant grade was tested according to UL94 vertical burning test standard.

[0049] The performance test results are shown in the following table: By analyzing the data in the above table, it can be seen that the high temperature resistant polyurethane adhesives prepared in Examples 1, 4, and 5 have higher shear strength than the high temperature resistant polyurethane adhesives prepared in Examples 6 and 7. This shows that in the total raw materials for preparing the high temperature resistant polyurethane adhesive of the present application, when the weight ratio of the mixture, aminosilane coupling agent, chitosan, epoxy resin, and ethanol aqueous solution in the modified inorganic heat-resistant flame retardant is 1: (0.40-0.52): 0.20: (0.10-0.14): 4, the high temperature resistance of the high temperature resistant polyurethane adhesive can be improved.

[0050] Compared with the high temperature resistant polyurethane adhesives prepared by using alicyclic epoxy resins in Examples 1 and 8, the shear strength of the high temperature resistant polyurethane adhesive prepared by using bisphenol A epoxy resin in Example 9 is significantly reduced. This shows that in the total raw materials for preparing the high temperature resistant polyurethane adhesive of the present application, the modified inorganic heat-resistant flame retardant prepared by using alicyclic epoxy resin can improve the high temperature resistance of the high temperature resistant polyurethane adhesive.

[0051] Compared with the high temperature resistant polyurethane adhesive prepared by using modified inorganic heat-resistant flame retardant in Example 1, the high temperature resistant polyurethane adhesive prepared by mixing inorganic heat-resistant agent and inorganic flame retardant in Comparative Example 2 has a relatively reduced shear strength of 23.24% and a flame retardant grade reduced to V-2.

[0052] Compared with the modified inorganic heat-resistant flame retardant prepared by chitosan and epoxy resin in Example 1, the modified inorganic heat-resistant flame retardant prepared by chitosan and water-based polyamide resin in Comparative Example 3 has a relatively reduced shear strength of 15.68% and a flame retardant grade reduced to V-1. This shows that in the total raw materials for preparing the high-temperature resistant polyurethane adhesive of the present application, the inorganic heat-resistant agent and the inorganic flame retardant are modified by chitosan and epoxy resin, which can improve the high-temperature resistance of the high-temperature resistant polyurethane adhesive.

[0053] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A high temperature resistant advertising paper, characterized in that: It includes an aluminum foil layer and an environmentally friendly release paper, wherein the aluminum foil layer and the environmentally friendly release paper are bonded by a high-temperature resistant polyurethane adhesive; The high temperature resistant polyurethane adhesive is composed of the following components in percentage by weight: Polyurethane resin 38-45%; Anti-aging agent 2-4%; Leveling agent 4-6%; Defoaming agent 1-3%; Modified inorganic heat-resistant flame retardant 3-5; Water 41-50%; The preparation method of the modified inorganic heat-resistant flame retardant comprises the following steps: A1: After stirring and mixing the aminosilane coupling agent and the ethanol aqueous solution, add the mixture of the inorganic heat resistant agent and the inorganic flame retardant, stir and mix to obtain a silane modified mixture; A2: Add chitosan and epoxy resin into the silane modified mixture, stir and mix, and obtain a heat-resistant flame-retardant modifier.

2. The high temperature resistant advertising paper according to claim 1, characterized in that: In the preparation method of the modified inorganic heat-resistant flame retardant, the weight ratio of the mixture, the aminosilane coupling agent, the chitosan, the epoxy resin and the ethanol aqueous solution is 1:(0.38-0.56):(0.15-0.22):(0.08-0.16):(2-5).

3. The high temperature resistant advertising paper according to claim 2, characterized in that: In the preparation method of the modified inorganic heat-resistant flame retardant, the weight ratio of the mixture, the aminosilane coupling agent, the chitosan, the epoxy resin and the ethanol aqueous solution is 1:(0.40-0.52):0.20:(0.10-0.14):

4.

4. The high temperature resistant advertising paper according to claim 1, characterized in that: In the preparation method of the modified inorganic heat-resistant flame retardant, the epoxy resin is an alicyclic epoxy resin.

5. The high temperature resistant advertising paper according to claim 5, characterized in that: The alicyclic epoxy resin has a viscosity of 300 to 450 cps at 25° C. and an epoxy equivalent of 131 to 143 g / Eq.

6. The high temperature resistant advertising paper according to claim 1, characterized in that: In the high temperature resistant polyurethane adhesive, the polyurethane resin is an anionic aliphatic waterborne polyurethane dispersion with a viscosity of 50 to 2000 mPa·s, a pH value of 6 to 8, and a solid content of 44 to 46.

7. The high temperature resistant advertising paper according to claim 1, characterized in that: In the high temperature resistant polyurethane adhesive, the inorganic flame retardant is a silver flame retardant.

8. The method for preparing the high temperature resistant advertising paper according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: After the polyurethane resin and water are stirred and mixed at 90-95° C. for 3-4 hours, the mixture is cooled to 30-35° C., an antioxidant, a leveling agent, a defoaming agent and a modified heat-resistant flame retardant are added, and the mixture is stirred and mixed to obtain a high-temperature resistant polyurethane adhesive; S2: coating the surface of the aluminum foil layer with a high-temperature resistant polyurethane adhesive, and then placing an environmentally friendly isolation paper on the side of the aluminum foil layer coated with the high-temperature resistant polyurethane adhesive, thereby obtaining the high-temperature resistant advertising paper.

9. A high temperature resistant polyurethane adhesive, characterized in that: It is composed of the following components in weight percentage: Polyurethane resin 38-45%; Anti-aging agent 2-4%; Leveling agent 4-6%; Defoaming agent 1-3%; Modified inorganic heat-resistant flame retardant 3-5; Water 41-50%; The preparation method of the modified inorganic heat-resistant flame retardant comprises the following steps: A1: After stirring and mixing the aminosilane coupling agent and the ethanol aqueous solution, add the mixture of the inorganic heat resistant agent and the inorganic flame retardant, stir and mix to obtain a silane modified mixture; A2: Add chitosan and epoxy resin into the silane modified mixture, stir and mix, and obtain a heat-resistant flame-retardant modifier.

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