Flame-retardant antioxidant laminated board and preparation method thereof

Abstract

The invention discloses a flame-retardant antioxidant laminated board and a preparation method thereof, the laminated board sequentially comprises a base material layer, a transition layer and antioxidant surface layers from inside to outside, and the antioxidant surface layers are symmetrically compounded on the two sides of the base material layer through the transition layer. The base material layer contains polypropylene, pretreated rice hull powder, microcapsule coated red phosphorus and a halogen-free basic flame retardant; the transition layer is based on epoxy resin, and a nano composite flame retardant, nano zinc oxide and a composite antioxidant are added; the anti-oxidation surface layer is prepared from modified PMMA (polymethyl methacrylate), an organic silicon flame retardant, a self-made anti-ultraviolet antioxidant and chitosan quaternary ammonium salt. The preparation method comprises the steps of melt extrusion of the base material layer, coating and pre-curing of the transition layer, co-extrusion of the surface layer and hot-pressing gradient cooling. The invention solves the problems of unbalanced flame retardance and environmental friendliness, single function, weak interlayer bonding and the like in the prior art, so that the laminated board has the advantages of no halogen, flame retardance, lasting oxidation resistance, ultraviolet resistance, antibacterial property and excellent mechanical properties, and is suitable for indoor decoration and other scenes.

Description

Technical Field

[0001] This invention relates to the field of laminate technology, specifically to a flame-retardant and oxidation-resistant laminate and its preparation method. Background Technology

[0002] With the increasing demands for material functionality and environmental friendliness in interior decoration, furniture manufacturing, and other fields, laminate has become one of the mainstream application materials due to its advantages of combining the mechanical support of the substrate with surface functional modification. Currently, laminates on the market generally face three major pain points: First, there is a serious imbalance between flame retardancy and environmental friendliness. Most high-efficiency flame-retardant laminates rely on halogenated flame retardants, which release toxic and harmful gases and corrosive fumes when burning, violating modern environmental regulations and indoor environmental safety requirements. Second, there is a prominent issue of functional uniformity. Existing products often focus on optimizing a single performance (such as only enhancing flame retardancy or wear resistance), lacking comprehensive coverage of key needs in indoor environments. The surface layer generally has weak resistance to ultraviolet radiation and oxidation, and is prone to yellowing, cracking, and performance degradation with long-term use. Third, the interlayer bonding performance is insufficient. Due to large differences in chemical structure, conventional laminates have poor interfacial compatibility. Traditional processes lack effective transition and bonding designs, resulting in low interlayer peel strength. When subjected to changes in temperature and humidity, delamination and blistering easily occur, severely shortening the service life. Summary of the Invention

[0003] The purpose of this invention is to provide a flame-retardant and oxidation-resistant laminate and its preparation method, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a flame-retardant and oxidation-resistant laminate, wherein the laminate comprises, from the inside out, a substrate layer, a transition layer, and an oxidation-resistant surface layer, wherein: The substrate layer comprises, by weight percentage: 40-60% polypropylene, 20-30% rice husk powder, 8-15% halogen-free basic flame retardant, 3-6% microencapsulated red phosphorus, 3-8% compatibilizer, 0.5-2% anti-aging additive, with the remainder being processing aids. The transition layer comprises, by weight percentage: 40-50% epoxy resin, 10-20% nano-composite flame retardant, 2-5% nano-zinc oxide, 2-5% composite antioxidant, 5-10% curing agent, 1-3% coupling agent, and the remainder being solvent. The antioxidant surface layer comprises, by weight percentage: 60-80% modified PMMA, 5-12% high-efficiency flame retardant, 3-6% UV antioxidant, 1-3% chitosan quaternary ammonium salt, 2-5% wear-resistant filler, 0.5-2% dispersant, and the balance being compatibilizer.

[0005] Preferably, the microcapsule-coated red phosphorus is coated with melamine-formaldehyde resin, with a coating rate of ≥90% and a particle size of 5-20μm.

[0006] Preferably, the halogen-free base flame retardant is a compound of ammonium polyphosphate and melamine cyanurate in a mass ratio of 1:1.5, and the processing aid is a compound of zinc stearate and antioxidant 168 in a mass ratio of 1:0.8.

[0007] Preferably, the compatibilizer is maleic anhydride-grafted polypropylene, and the anti-aging additive is a compound of UV-327 and hindered amine light stabilizer 770 in a mass ratio of 2:1.

[0008] Preferably, the nanocomposite flame retardant is a compound of magnesium hydroxide and montmorillonite in a mass ratio of 3:1, and the composite antioxidant is a compound of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0009] Preferably, the curing agent is polyamide 650, the coupling agent is KH560, and the solvent is anhydrous ethanol.

[0010] Preferably, the modified PMMA is a methyl methacrylate-styrene copolymer with a styrene content of 10-15%, and the wear-resistant filler is silane coupling agent modified nano-silica.

[0011] Preferably, the high-efficiency flame retardant is aluminum phosphonate.

[0012] This invention also provides a method for preparing a flame-retardant and oxidation-resistant laminate, comprising the following steps: S1. Add pretreated rice husk powder, polypropylene, halogen-free basic flame retardant, microencapsulated red phosphorus, compatibilizer, anti-aging agent and processing aid to a high-speed mixer, mix at 90°C for 20 minutes, and send to a twin-screw extruder for melt extrusion molding. Cool to obtain the substrate layer. The barrel temperature is 180°C and the screw speed is 120 r / min. S2. Mix epoxy resin, nano-composite flame retardant, nano zinc oxide, composite antioxidant, curing agent, coupling agent and solvent for 30 minutes to prepare a transition layer coating. Apply the coating to both sides of the substrate layer with a scraper, with a thickness of 0.08-0.15 mm, and pre-cur at 90℃ for 20 minutes to obtain a pre-composite substrate. S3. Modified PMMA, high-efficiency flame retardant, UV antioxidant, chitosan quaternary ammonium salt, wear-resistant filler, dispersant and compatibilizer are added to the screw extruder and melt-mixed at 200℃. The die head temperature is set at 200℃ and the melt pressure is 10MPa through the co-extrusion die to form an antioxidant surface layer on the transition layer surface. S4. The composite board is fed into a hot press and hot-pressed at 130℃ and 5MPa for 8 minutes. After cooling to room temperature, it is cut to obtain a flame-retardant and oxidation-resistant laminate.

[0013] Preferably, in S1, the twin-screw extruder has 6 temperature zones, which are 170°C, 175°C, 180°C, 185°C, 190°C and 185°C respectively from the feed end to the discharge port.

[0014] Compared with existing technologies, the beneficial effects of this invention are as follows: The laminate provided by this invention adopts a halogen-free design for flame retardancy. The substrate layer of ammonium polyphosphate-melamine cyanurate synergistically combines with microcapsule red phosphorus with a coverage rate of ≥90%. The transition layer of magnesium hydroxide-montmorillonite and the surface layer of aluminum phosphonate construct multiple flame-retardant barriers, achieving highly efficient flame retardancy without the release of toxic gases. Functionally, it forms triple protection through the surface layer of UV-resistant antioxidants, the transition layer of composite antioxidants, and the substrate layer of anti-aging additives. Combined with chitosan quaternary ammonium salt, it achieves antibacterial properties, preventing yellowing and mold growth. The epoxy resin in the transition layer and KH560 coupling agent form a chemical bridge, significantly improving the interlayer peel strength. The substrate and modified fillers synergistically optimize mechanical properties, and the process parameters are clear and controllable. The product is suitable for interior decoration, combining environmental protection and practicality. Attached Figure Description

[0015] Figure 1 This is a schematic flowchart illustrating the preparation method of the flame-retardant and oxidation-resistant laminate according to an embodiment of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0017] Please see Figure 1 The present invention provides a flame-retardant and oxidation-resistant laminate, which comprises, from the inside out, a substrate layer, a transition layer, and an oxidation-resistant surface layer. The oxidation-resistant surface layer is symmetrically laminated to both sides of the substrate layer through the transition layer, wherein: The substrate layer, by weight percentage, includes: 50% polypropylene, 25% rice husk powder, 12% halogen-free basic flame retardant, 4% microencapsulated red phosphorus, 5% compatibilizer, 1% anti-aging additive, and the remainder is processing aids. The transition layer, by weight percentage, comprises: 45% epoxy resin, 15% nano-composite flame retardant, 3% nano zinc oxide, 3% composite antioxidant, 8% curing agent, 2% coupling agent, and the remainder is solvent. The antioxidant surface layer, by weight percentage, comprises: 70% modified PMMA, 8% high-efficiency flame retardant, 4% UV antioxidant, 2% chitosan quaternary ammonium salt, 3% wear-resistant filler, 0.5% dispersant, and the balance being compatibilizer. Example

[0018] This embodiment provides a flame-retardant and oxidation-resistant laminate, which comprises, from the inside out, a substrate layer, a transition layer, and an oxidation-resistant surface layer. The oxidation-resistant surface layer is symmetrically laminated to both sides of the substrate layer through the transition layer, wherein: The substrate layer, by weight percentage, comprises: 45% polypropylene, 30% rice husk powder, 10% halogen-free basic flame retardant, 6% microencapsulated red phosphorus, 6% compatibilizer, 0.8% anti-aging additive, with the remainder being processing aids.

[0019] The transition layer, by weight percentage, comprises: 40% epoxy resin, 20% nano-composite flame retardant, 5% nano zinc oxide, 5% composite antioxidant, 10% curing agent, 3% coupling agent, and the remainder is solvent.

[0020] The antioxidant surface layer, by weight percentage, comprises: 65% modified PMMA, 12% high-efficiency flame retardant, 6% UV antioxidant, 3% chitosan quaternary ammonium salt, 5% wear-resistant filler, 2% dispersant, and the balance being compatibilizer. Example

[0021] This embodiment provides a flame-retardant and oxidation-resistant laminate, which comprises, from the inside out, a substrate layer, a transition layer, and an oxidation-resistant surface layer. The oxidation-resistant surface layer is symmetrically laminated to both sides of the substrate layer through the transition layer, wherein: The substrate layer, by weight percentage, comprises: 60% polypropylene, 20% rice husk powder, 15% halogen-free basic flame retardant, 3% microencapsulated red phosphorus, 3% compatibilizer, 2% anti-aging additive, and the remainder being processing aids.

[0022] The transition layer, by weight percentage, comprises: 50% epoxy resin, 10% nano-composite flame retardant, 2% nano zinc oxide, 2% composite antioxidant, 5% curing agent, 1% coupling agent, and the remainder is solvent.

[0023] The antioxidant surface layer, by weight percentage, comprises: 80% modified PMMA, 5% high-efficiency flame retardant, 3% UV antioxidant, 1% chitosan quaternary ammonium salt, 2% wear-resistant filler, 0.5% dispersant, and the balance being compatibilizer.

[0024] Furthermore, embodiments of the present invention also provide a method for preparing a flame-retardant and oxidation-resistant laminate, used to prepare the laminates provided in Examples 1-3, comprising the following steps: S1. Preparation of substrate layer: Pretreated rice husk powder, polypropylene, halogen-free basic flame retardant, microencapsulated red phosphorus, compatibilizer, anti-aging agent and processing aid are added to a high-speed mixer and mixed at 90°C for 20 minutes. The mixture is then fed into a twin-screw extruder for melt extrusion molding and cooled to obtain the substrate layer. The barrel temperature is 180°C and the screw speed is 120 r / min. S2. Transition layer coating: Mix epoxy resin, nano-composite flame retardant, nano zinc oxide, composite antioxidant, curing agent, coupling agent and solvent for 30 minutes to prepare transition layer coating. Apply the coating to both sides of the substrate layer with a scraper, with a thickness of 0.08-0.15 mm. Pre-cur at 90℃ for 20 minutes to obtain pre-composite substrate. S3. Preparation of antioxidant surface layer: Modified PMMA, high-efficiency flame retardant, UV antioxidant, chitosan quaternary ammonium salt, wear-resistant filler, dispersant and compatibilizer are added to screw extruder and melt-mixed at 200℃. The die head temperature is set at 200℃ and the melt pressure is 10MPa through co-extrusion die to form antioxidant surface layer on the transition layer surface. S4. Hot pressing treatment: The composite board is fed into a hot press and hot-pressed at 130℃ and 5MPa for 8 minutes. After cooling to room temperature, it is cut to obtain a flame-retardant and oxidation-resistant laminate.

[0025] Furthermore, in S1, the twin-screw extruder is equipped with 6 temperature zones, which are 170℃, 175℃, 180℃, 185℃, 190℃, and 185℃ respectively from the feed end to the discharge port.

[0026] Specifically, in the flame-retardant and antioxidant laminates provided in Examples 1-3, the microcapsule-encapsulated red phosphorus in the substrate layer is encapsulated with melamine-formaldehyde resin, with an encapsulation rate ≥90% and a particle size of 5-20μm. The halogen-free base flame retardant is a compound of ammonium polyphosphate and melamine cyanurate in a mass ratio of 1:1.5. The processing aid is a compound of zinc stearate and antioxidant 168 in a mass ratio of 1:0.8. The compatibilizer is maleic anhydride-grafted polypropylene. The anti-aging aid is a compound of UV-327 and hindered amine light stabilizer 770 in a mass ratio of 2:1.

[0027] The nanocomposite flame retardant in the transition layer is a mixture of magnesium hydroxide and montmorillonite in a mass ratio of 3:1, the composite antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1, the curing agent is polyamide 650, the coupling agent is KH560, and the solvent is anhydrous ethanol.

[0028] The modified PMMA in the antioxidant surface layer is a methyl methacrylate-styrene copolymer with a styrene content of 10-15%, the wear-resistant filler is silane coupling agent modified nano-silica, the high-efficiency flame retardant is aluminum hypophosphite, and the quaternization degree of chitosan quaternary ammonium salt is ≥75%, with a molecular weight of 20,000-50,000 Da.

[0029] Comparative Example 1 Composition: Only the substrate layer and antioxidant surface layer of Example 1 are retained, and the transition layer is removed; Preparation: The surface layer is co-extruded directly onto the surface of the substrate layer, and the other raw materials are the same as in Example 1.

[0030] Comparative Example 2 The components are as follows: Substrate layer: 16% decabromodiphenyl ether (halogenated flame retardant) is used to replace the halogen-free base flame retardant and microcapsule-encapsulated red phosphorus, while removing anti-aging additives; Transition layer: Removes complex antioxidants; Surface layer: 8% decabromodiphenyl ether is used to replace aluminum phosphonate to remove UV-resistant antioxidants; Preparation: Same as in Example 1.

[0031] Test case This experiment tested the performance of the laminates prepared in Examples 1-3 and Comparative Examples 1-2. The test standards and methods are as follows: Limiting oxygen index (LOI): determined according to GB / T2406.2-2009; Interlayer peel strength: determined according to GB / T1457-2005; UV aging yellowing index (ΔE): determined according to GB / T2409-1980 after xenon lamp aging test (1000h, irradiance 0.51W / (m²・nm)); Antibacterial rate: determined according to GB / T21510-2008, the test species were Escherichia coli and Staphylococcus aureus; Tensile strength: determined according to GB / T1040.2-2006; Toxic gas release during combustion: Combustion products were detected using gas chromatography-mass spectrometry (GC-MS). In summary: The laminate of Example 2 exhibits excellent overall performance. The limiting oxygen index (LOI) of Examples 1-3 all exceed 31.8%, significantly better than Comparative Example 1 without a transition layer. Furthermore, no toxic gases are released during combustion, resolving the environmental hazards associated with the halogen-containing flame retardant in Comparative Example 2 and achieving highly efficient halogen-free flame retardancy. The addition of the transition layer increases the interlayer peel strength of Examples 1 to 4.5-5 MPa, a significant improvement over Comparative Example 1, effectively addressing the problem of weak interlayer bonding.

[0032] The UV aging yellowing index is only 1.1-1.5, far lower than the 8.7 of Comparative Example 2, demonstrating the significant effectiveness of the triple anti-aging protection system. Simultaneously, the antibacterial rate is close to 99%, and the tensile strength reaches 33.8-37.2 MPa, combining antibacterial properties with excellent mechanical properties. Therefore, this invention, through multiple halogen-free flame-retardant designs, chemical bridging of the transition layer, and the compounding of anti-aging and antibacterial components, is more suitable for the needs of interior decoration and other scenarios.

[0033] All parts not described in this invention are the same as or can be implemented using existing technology. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A flame-retardant and oxidation-resistant laminate, characterized in that, The laminate comprises, from the inside out, a substrate layer, a transition layer, and an antioxidant surface layer, wherein: The substrate layer comprises, by weight percentage: 40-60% polypropylene, 20-30% rice husk powder, 8-15% halogen-free basic flame retardant, 3-6% microencapsulated red phosphorus, 3-8% compatibilizer, 0.5-2% anti-aging additive, with the remainder being processing aids. The transition layer comprises, by weight percentage: 40-50% epoxy resin, 10-20% nano-composite flame retardant, 2-5% nano-zinc oxide, 2-5% composite antioxidant, 5-10% curing agent, 1-3% coupling agent, and the remainder being solvent. The antioxidant surface layer comprises, by weight percentage: 60-80% modified PMMA, 5-12% high-efficiency flame retardant, 3-6% UV antioxidant, 1-3% chitosan quaternary ammonium salt, 2-5% wear-resistant filler, 0.5-2% dispersant, and the balance being compatibilizer.

2. The flame-retardant and oxidation-resistant laminate according to claim 1, characterized in that: The microcapsule-coated red phosphorus is coated with melamine-formaldehyde resin, with a coating rate of ≥90% and a particle size of 5-20μm.

3. The flame-retardant and oxidation-resistant laminate according to claim 1, characterized in that: The halogen-free base flame retardant is a compound of ammonium polyphosphate and melamine cyanurate in a mass ratio of 1:1.5, and the processing aid is a compound of zinc stearate and antioxidant 168 in a mass ratio of 1:0.

8.

4. The flame-retardant and oxidation-resistant laminate according to claim 1, characterized in that: The compatibilizer is selected as maleic anhydride-grafted polypropylene, and the anti-aging additive is a compound of UV-327 and hindered amine light stabilizer 770 in a mass ratio of 2:

1.

5. The flame-retardant and oxidation-resistant laminate according to claim 1, characterized in that: The nanocomposite flame retardant is a compound of magnesium hydroxide and montmorillonite in a mass ratio of 3:1, and the composite antioxidant is a compound of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:

1.

6. The flame-retardant and oxidation-resistant laminate according to claim 1, characterized in that: The curing agent is polyamide 650, the coupling agent is KH560, and the solvent is anhydrous ethanol.

7. The flame-retardant and oxidation-resistant laminate according to claim 1, characterized in that: The modified PMMA is a methyl methacrylate-styrene copolymer with a styrene content of 10-15%, and the wear-resistant filler is silane coupling agent modified nano-silica.

8. The flame-retardant and oxidation-resistant laminate according to claim 1, characterized in that: The high-efficiency flame retardant is aluminum phosphonate.

9. A method for preparing a flame-retardant and oxidation-resistant laminate, characterized in that, Includes the following steps: S1. Add pretreated rice husk powder, polypropylene, halogen-free basic flame retardant, microencapsulated red phosphorus, compatibilizer, anti-aging agent and processing aid to a high-speed mixer, mix at 90°C for 20 minutes, and send to a twin-screw extruder for melt extrusion molding. Cool to obtain the substrate layer. The barrel temperature is 180°C and the screw speed is 120 r / min. S2. Mix epoxy resin, nano-composite flame retardant, nano zinc oxide, composite antioxidant, curing agent, coupling agent and solvent for 30 minutes to prepare a transition layer coating. Apply the coating to both sides of the substrate layer with a scraper, with a thickness of 0.08-0.15 mm, and pre-cur at 90℃ for 20 minutes to obtain a pre-composite substrate. S3. Modified PMMA, high-efficiency flame retardant, UV antioxidant, chitosan quaternary ammonium salt, wear-resistant filler, dispersant and compatibilizer are added to the screw extruder and melt-mixed at 200℃. The die head temperature is set at 200℃ and the melt pressure is 10MPa through the co-extrusion die to form an antioxidant surface layer on the transition layer surface. S4. The composite board is fed into a hot press and hot-pressed at 130℃ and 5MPa for 8 minutes. After cooling to room temperature, it is cut to obtain a flame-retardant and oxidation-resistant laminate.

10. The method for preparing the flame-retardant and oxidation-resistant laminate according to claim 9, characterized in that: In S1, the twin-screw extruder has 6 temperature zones, which are 170℃, 175℃, 180℃, 185℃, 190℃ and 185℃ respectively from the feed end to the discharge port.

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