Multilayer composite rubber-plastic foamed thermal insulation material and preparation method thereof
By designing a multi-layer composite rubber-plastic foam material, and utilizing the alternating stacking and vulcanization foaming of modified sericite A and B, the problem of large and unevenly distributed pores in rubber-plastic foam materials at high foaming ratios was solved, thereby improving the mechanical properties, anti-aging properties, and thermal insulation properties of the material.
Patent Information
- Application Number
- CN202611471583.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-21
- Publication Date
- 2026-11-06
AI Technical Summary
Existing rubber and plastic foam materials have large and unevenly distributed pores at high foaming ratios, which leads to reduced matrix strength, insufficient mechanical properties, and easy aging in long-term hot and oxygen environments.
A multi-layer composite structure is adopted, with rubber and plastic material A as the foaming layer and rubber and plastic material B as the dense layer. The multi-layer composite rubber and plastic foam insulation material is prepared by alternating stacking and co-vulcanization foaming. Modified sericite A is introduced into rubber and plastic material A as heterogeneous nucleation points, and modified sericite B is introduced into material B to improve interfacial compatibility. The dense layer clamps and constrains the foaming layer.
This achieves uniform and stable cell structure, improves the material's mechanical properties and anti-aging properties, while maintaining good thermal insulation performance.
Smart Images
Figure REF-OBJ-1789973009054-000001
Abstract
Description
Technical Field
[0001] This invention relates to the field of multilayer composite material technology, specifically a multilayer composite rubber-plastic foam insulation material and its preparation method. Background Technology
[0002] Rubber-plastic foam materials are porous polymer composite materials made from rubber and plastic as the matrix through a foaming process. They possess both the elasticity of rubber and the strength of plastic and are widely used in building insulation, pipe insulation, equipment cushioning, and other fields. In existing technologies, commonly used industrial rubber-plastic foam materials mostly adopt a single foam structure, reducing density by increasing the foaming ratio to obtain a lower thermal conductivity.
[0003] However, high foaming ratio rubber and plastic materials often have large and unevenly distributed pores, which inevitably weakens the matrix strength and reduces mechanical properties. At the same time, the high specific surface area of the pore walls and the weak structure also make them more prone to aging and degradation in long-term hot and oxygen environments.
[0004] In summary, solving the above problems and providing a multilayer composite rubber-plastic foam insulation material and its preparation method is of great significance. Summary of the Invention
[0005] The purpose of this invention is to provide a multilayer composite rubber-plastic foam insulation material and its preparation method to solve the problems mentioned in the background art.
[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a multilayer composite rubber-plastic foam insulation material, comprising the following steps: S1: Alternately stack rubber-plastic material A and rubber-plastic material B to obtain an unfoamed multilayer composite material with rubber-plastic material B as the outermost layer; S2: Place the unfoamed multilayer composite material into a mold, and hot-press it to foam and vulcanize it to obtain a multilayer composite rubber-plastic foam insulation material. The raw materials of the rubber-plastic material A include nitrile rubber / polyvinyl chloride with a rubber-plastic ratio of 60:40, modified sericite A, and a foaming agent; the raw materials of the rubber-plastic material B include nitrile rubber / polyvinyl chloride with a rubber-plastic ratio of 50:50, modified sericite B, and an antioxidant. The modified sericite A was prepared from N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-modified thiolated sericite; the modified sericite B was prepared from isopropyltris(dioctylpyrophosphate)titanate and white oil-modified sericite.
[0007] Preferably, the rubber-plastic material A comprises the following raw materials in parts by weight: 60 parts nitrile rubber, 40 parts polyvinyl chloride, 8-12 parts modified sericite A, 2-3 parts calcium-zinc composite stabilizer, 1-1.5 parts zinc stearate, 15-20 parts plasticizer, 1-2 parts stearic acid, 3-5 parts zinc oxide, 4-8 parts foaming agent, 2-3 parts vulcanizing agent, 1.5-2 parts accelerator CZ, and 0.5-1 part accelerator TMTD.
[0008] Preferred method for preparing modified sericite A includes the following steps: (1) ultrasonically dispersing sericite in an ethanol aqueous solution, adding 1-1.5 parts of mercaptopropyltrimethoxysilane, stirring and reacting at 40-50°C for 5-8 hours, filtering, washing, and drying to obtain mercapto-modified sericite. (2) Thiolized sericite and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine were added to acetone and ultrasonically dispersed evenly. The mixture was stirred at 20-25°C for 10-12 hours, then vacuumed for 1-2 hours, filtered, washed, and dried to obtain modified sericite A.
[0009] Preferably, the mercaptolated sericite comprises the following raw materials, in parts by mass: 8-10 parts sericite, 100-150 parts aqueous ethanol solution, and 1-1.5 parts mercaptopropyltrimethoxysilane; The modified sericite A comprises the following raw materials, in parts by mass: 8-10 parts mercapto-modified sericite and 3-6 parts N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine.
[0010] Preferably, the rubber-plastic material B comprises the following raw materials in parts by weight: 50 parts nitrile rubber, 50 parts polyvinyl chloride, 5-10 parts modified sericite B, 2-3 parts calcium-zinc composite stabilizer, 1-1.5 parts zinc stearate, 15-20 parts plasticizer, 1-2 parts stearic acid, 3-5 parts zinc oxide, 1-3 parts antioxidant RD, 2-3 parts vulcanizing agent, 1.5-2 parts accelerator CZ, and 0.5-1 part accelerator TMTD.
[0011] Preferredly, the preparation method of the modified sericite B includes the following steps: adding sericite, isopropyl tris(dioctyl pyrophosphoryloxy) titanate, and white oil into a high-speed mixer and mixing for 5-10 minutes to obtain modified sericite B.
[0012] Preferably, the modified sericite B comprises the following raw materials, in parts by mass: 8-10 parts sericite, 0.1-0.3 parts isopropyl tris(dioctyl pyrophosphate) titanate, and 0.1-0.3 parts white oil.
[0013] Preferably, the thickness ratio of the rubber-plastic material A to the rubber-plastic material B is 1 to 3:1; the total number of layers of the unfoamed multilayer composite material is 9, 11, 13, 15, 17 or 19 layers.
[0014] Preferably, during the hot-pressing foaming vulcanization process, the foaming expansion gap is 10-30% of the total thickness of the unfoamed multilayer composite material; the vulcanization temperature is 160-170℃, the pressure is 10-15MPa, and the time is 5-15min; the thickness of the multilayer composite rubber-plastic foam insulation material is 5-10mm.
[0015] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention uses nitrile rubber / polyvinyl chloride (NBR / PVC) with a rubber-to-plastic ratio of 60:40, modified sericite A, azodicarbonamide as a foaming agent, and a vulcanization system as raw materials to prepare rubber-plastic material A as a foaming layer; and uses nitrile rubber / PVC with a rubber-to-plastic ratio of 50:50, modified sericite B, antioxidant RD, and a vulcanization system as raw materials to prepare rubber-plastic material B as a dense layer. By alternately stacking and co-vulcanizing and foaming, the resulting multilayer composite rubber-plastic foam material has uniform and fine pores. Each component layer has good mechanical properties and anti-aging properties, and compared with single-layer rubber-plastic foam material, the multilayer composite material has better thermal insulation performance.
[0016] Among them, rubber-plastic materials based on nitrile rubber / polyvinyl chloride combine the flexibility of rubber with the processability of plastics, exhibiting good durability and thermal stability. By introducing foaming agents, they can be made into porous rubber-plastic foam materials, characterized by light weight and low thermal conductivity, suitable for applications such as thermal insulation, sound insulation, and cushioning. When applied to thermal insulation materials, since the thermal conductivity decreases with increasing cell count or porosity, a larger amount of foaming agent is generally required to increase the foaming ratio and porosity, thereby achieving good thermal insulation performance. However, when such insulation materials are used in applications requiring bending, stretching, and deformation, the large amount of foaming agent results in large, unevenly distributed cells, weakening the matrix strength and making the material prone to breakage. Furthermore, the large cells form interconnected pores, increasing the contact area between oxygen and the matrix, thus making it more susceptible to thermo-oxidative aging.
[0017] Therefore, this application uses rubber and plastic material A as the foaming layer and rubber and plastic material B as the dense layer, and prepares a multi-layer composite rubber and plastic foam insulation material by alternating stacking and co-vulcanization foaming. Among them, the rubber-plastic material A adopts a rubber-plastic ratio of 60:40, with a high rubber phase content, good matrix elasticity, and less prone to collapse during foaming. Modified sericite A is introduced into the matrix, which is prepared by physical adsorption and hydrogen bonding of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and mercapto-modified sericite. Surface modification improves the dispersibility of sericite in the matrix, thus serving as a heterogeneous nucleation site to promote uniform cell nucleation, improve cell uniformity and stability, and reduce the occurrence of fused and cross-cell structures. At the same time, the antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine is fixed on the surface of sericite. Compared with directly adding anti-aging agents, it can be better fixed to the cell walls, improving anti-aging performance and durability, and compensating for the insufficient anti-aging performance of the foam layer caused by the cell structure.
[0018] Rubber-plastic material B, with a 50:50 rubber-plastic ratio and a relatively higher polyvinyl chloride (PVC) content, provides basic mechanical properties and dimensional stability. Simultaneously, modified sericite B, prepared by surface modification of isopropyl tris(dioctyl pyrophosphate) titanate and white oil, is introduced. The introduction of this titanate coupling agent under this rubber-plastic ratio condition better improves interfacial compatibility, thereby enhancing mechanical properties. Since rubber-plastic material B does not contain a foaming agent, the introduction of a dense layer slightly increases the overall thermal conductivity of the material. However, during the foaming process of rubber-plastic material A, the dense layer provides bidirectional clamping and constraint to the foamed layer, limiting excessive expansion and disordered growth of cells, improving cell uniformity and quantity, thus enabling the composite material to maintain good thermal insulation performance while possessing excellent mechanical properties.
[0019] However, the total number of alternating layers in the composite material needs to be limited: when the number of layers is too small, the thickness of a single foam layer is too large, the constraint effect of the dense layer on cell growth is weakened, the foaming uniformity deteriorates, and the proportion of the dense layer is too high, resulting in a continuous solid-phase thermal conductivity path and a decrease in thermal insulation performance; when the number of layers is too large, the thickness of a single foam layer is too small, the clamping constraint of the dense layer is too strong, the generation of cells is inhibited, the number of cells is reduced, and the thermal insulation performance decreases. Therefore, this application designs the total number of layers to be an odd number of 9 to 19 layers, which is more suitable to achieve good mechanical properties and thermal insulation effect, while also having excellent anti-aging properties. Detailed Implementation
[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.
[0021] Wherein, part is mass part; under non-foaming conditions, the thickness ratio of rubber-plastic material A and rubber-plastic material B is 1:1; the preparation process of modified sericite A is as follows: (1) 10 parts of sericite are ultrasonically dispersed in 100 parts of ethanol aqueous solution with a volume fraction of 90%, 1.4 parts of mercaptopropyltrimethoxysilane are added dropwise, and the mixture is stirred at 50°C for 6 hours. After filtration, washing, and drying, mercapto-modified sericite is obtained; (2) 10 parts of mercapto-modified sericite and 4.5 parts of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine are added to acetone and ultrasonically dispersed evenly. After stirring at 25°C for 12 hours, vacuum is applied for 2 hours. After filtration, washing, and drying, modified sericite A is obtained; The preparation process of modified sericite B is as follows: 10 parts of sericite, 0.2 parts of isopropyl tris(dioctyl pyrophosphoryloxy) titanate, and 0.2 parts of white oil are added to a high-speed mixer and mixed for 8 minutes to obtain modified sericite B.
[0022] Example 1: A method for preparing a multilayer composite rubber-plastic foam insulation material includes the following steps: Step 1: Preparation of Rubber-Plastic Material A: Mix 40 parts of polyvinyl chloride powder, 10 parts of modified sericite A, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 60 parts of nitrile rubber, 1.4 parts of stearic acid, and 4 parts of zinc oxide at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 6 parts of foaming agent azodicarbonamide, 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material A; Step 2: Preparation of Rubber-Plastic Material B: Mix 50 parts of polyvinyl chloride powder, 8 parts of modified sericite B, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 50 parts of nitrile rubber, 1.4 parts of stearic acid, 4 parts of zinc oxide, and 2 parts of antioxidant RD at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material B; Step 3: Preparation of composite materials: S1: Rubber-plastic material A and rubber-plastic material B are stacked alternately to obtain an unfoamed multilayer composite material with a total of 13 layers and the outermost layer being rubber-plastic material B. S2: Place the unfoamed multilayer composite material into the mold, with the foaming expansion gap being 25% of the total thickness of the unfoamed multilayer composite material; use a flat vulcanizing machine at 160℃ and a pressure of 12MPa for 12 minutes to foam and vulcanize, obtaining a multilayer composite rubber-plastic foam insulation material with a thickness of 10mm.
[0023] Among them, the polyvinyl chloride powder is graded WS-1000S; the nitrile rubber is graded NBR-3355, with an acrylonitrile mass fraction of 33wt%; the sericite has a particle size of 5~10μm; the CAS number of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine is 793-24-8; and the CAS number of isopropyltris(dioctylpyrophosphate)titanate is 67691-13-8.
[0024] Example 2: A method for preparing a multilayer composite rubber-plastic foam insulation material includes the following steps: Step 1: Preparation of Rubber-Plastic Material A: Mix 40 parts of polyvinyl chloride powder, 8 parts of modified sericite A, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 60 parts of nitrile rubber, 1.4 parts of stearic acid, and 4 parts of zinc oxide at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 8 parts of foaming agent azodicarbonamide, 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material A; Step 2: Preparation of Rubber-Plastic Material B: Mix 50 parts of polyvinyl chloride powder, 10 parts of modified sericite B, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 50 parts of nitrile rubber, 1.4 parts of stearic acid, 4 parts of zinc oxide, and 2 parts of antioxidant RD at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material B; Step 3: Preparation of composite materials: S1: Rubber-plastic material A and rubber-plastic material B are stacked alternately to obtain an unfoamed multilayer composite material with a total of 9 layers and the outermost layer being rubber-plastic material B. S2: Place the unfoamed multilayer composite material into the mold, with the foaming expansion gap being 25% of the total thickness of the unfoamed multilayer composite material; use a flat vulcanizing machine at 160℃ and a pressure of 12MPa for 12 minutes to foam and vulcanize, obtaining a multilayer composite rubber-plastic foam insulation material with a thickness of 10mm.
[0025] Example 3: A method for preparing a multilayer composite rubber-plastic foam insulation material includes the following steps: Step 1: Preparation of Rubber-Plastic Material A: Mix 40 parts of polyvinyl chloride powder, 12 parts of modified sericite A, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 60 parts of nitrile rubber, 1.4 parts of stearic acid, and 4 parts of zinc oxide at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 4 parts of foaming agent azodicarbonamide, 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material A; Step 2: Preparation of Rubber-Plastic Material B: Mix 50 parts of polyvinyl chloride powder, 5 parts of modified sericite B, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 50 parts of nitrile rubber, 1.4 parts of stearic acid, 4 parts of zinc oxide, and 2 parts of antioxidant RD at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material B; Step 3: Preparation of composite materials: S1: Rubber-plastic material A and rubber-plastic material B are stacked alternately to obtain an unfoamed multilayer composite material with a total of 17 layers and the outermost layer being rubber-plastic material B. S2: Place the unfoamed multilayer composite material into the mold, with the foaming expansion gap being 25% of the total thickness of the unfoamed multilayer composite material; use a flat vulcanizing machine at 160℃ and a pressure of 12MPa for 12 minutes to foam and vulcanize, obtaining a multilayer composite rubber-plastic foam insulation material with a thickness of 10mm.
[0026] Comparative Example 1: Based on Example 1, in the preparation process of rubber and plastic material A, the modified sericite A only underwent thiol modification, and the anti-aging agent RD was added. The rest of the process remained unchanged, as follows: Step 1: Preparation of Rubber-Plastic Material A: Mix 40 parts of polyvinyl chloride powder, 10 parts of modified sericite A, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 60 parts of nitrile rubber, 1.4 parts of stearic acid, 4 parts of zinc oxide, and 2 parts of anti-aging agent RD at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 6 parts of foaming agent azodicarbonamide, 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material A; Step 2: Preparation of Rubber-Plastic Material B: Mix 50 parts of polyvinyl chloride powder, 8 parts of modified sericite B, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 50 parts of nitrile rubber, 1.4 parts of stearic acid, 4 parts of zinc oxide, and 2 parts of antioxidant RD at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material B; Step 3: Preparation of composite materials: S1: Rubber-plastic material A and rubber-plastic material B are stacked alternately to obtain an unfoamed multilayer composite material with a total of 13 layers and the outermost layer being rubber-plastic material B. S2: Place the unfoamed multilayer composite material into the mold, with the foaming expansion gap being 25% of the total thickness of the unfoamed multilayer composite material; use a flat vulcanizing machine at 160℃ and a pressure of 12MPa for 12 minutes to foam and vulcanize, obtaining a multilayer composite rubber-plastic foam insulation material with a thickness of 10mm.
[0027] The preparation process of modified sericite A is as follows: (1) 10 parts of sericite are ultrasonically dispersed in 100 parts of ethanol aqueous solution with a volume fraction of 90%, and 1.4 parts of mercaptopropyltrimethoxysilane are added dropwise. The mixture is stirred at 50°C for 6 hours, filtered, washed, and dried to obtain modified sericite A. Comparative Example 2: Based on Example 1, in the preparation process of rubber-plastic material A, the rubber-plastic ratio was 50:50, and the other processes remained unchanged, as follows: Step 1: Preparation of Rubber-Plastic Material A: Mix 50 parts of polyvinyl chloride powder, 10 parts of modified sericite A, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 50 parts of nitrile rubber, 1.4 parts of stearic acid, and 4 parts of zinc oxide at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 6 parts of foaming agent azodicarbonamide, 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material A; Step 2: Preparation of Rubber-Plastic Material B: Mix 50 parts of polyvinyl chloride powder, 8 parts of modified sericite B, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 50 parts of nitrile rubber, 1.4 parts of stearic acid, 4 parts of zinc oxide, and 2 parts of antioxidant RD at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material B; Step 3: Preparation of composite materials: S1: Rubber-plastic material A and rubber-plastic material B are stacked alternately to obtain an unfoamed multilayer composite material with a total of 13 layers and the outermost layer being rubber-plastic material B. S2: Place the unfoamed multilayer composite material into the mold, with the foaming expansion gap being 25% of the total thickness of the unfoamed multilayer composite material; use a flat vulcanizing machine at 160℃ and a pressure of 12MPa for 12 minutes to foam and vulcanize, obtaining a multilayer composite rubber-plastic foam insulation material with a thickness of 10mm.
[0028] Comparative Example 3: Based on Example 1, the modified sericite B in the preparation of rubber-plastic material B was modified with isopropyl triisostearoyl titanate, while the remaining processes remained unchanged, as follows: The preparation process of modified sericite B is as follows: 10 parts of sericite, 0.2 parts of isopropyl triisostearoyl titanate, and 0.2 parts of white oil are added to a high-speed mixer and mixed for 8 minutes to obtain modified sericite B.
[0029] Step 1: Preparation of Rubber-Plastic Material A: Mix 40 parts of polyvinyl chloride powder, 10 parts of modified sericite A, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 60 parts of nitrile rubber, 1.4 parts of stearic acid, and 4 parts of zinc oxide at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 6 parts of foaming agent azodicarbonamide, 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material A; Step 2: Preparation of Rubber-Plastic Material B: Mix 50 parts of polyvinyl chloride powder, 8 parts of modified sericite B, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 50 parts of nitrile rubber, 1.4 parts of stearic acid, 4 parts of zinc oxide, and 2 parts of antioxidant RD at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material B; Step 3: Preparation of composite materials: S1: Rubber-plastic material A and rubber-plastic material B are stacked alternately to obtain an unfoamed multilayer composite material with a total of 13 layers and the outermost layer being rubber-plastic material B. S2: Place the unfoamed multilayer composite material into the mold, with the foaming expansion gap being 25% of the total thickness of the unfoamed multilayer composite material; use a flat vulcanizing machine at 160℃ and a pressure of 12MPa for 12 minutes to foam and vulcanize, obtaining a multilayer composite rubber-plastic foam insulation material with a thickness of 10mm.
[0030] Comparative Example 4: Based on Example 1, in the preparation process of the multi-layer composite rubber-plastic foam insulation material, the total number of layers was set to 23, and the remaining processes remained unchanged, as follows: Step 1: Preparation of Rubber-Plastic Material A: Mix 40 parts of polyvinyl chloride powder, 10 parts of modified sericite A, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 60 parts of nitrile rubber, 1.4 parts of stearic acid, and 4 parts of zinc oxide at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 6 parts of foaming agent azodicarbonamide, 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material A; Step 2: Preparation of Rubber-Plastic Material B: Mix 50 parts of polyvinyl chloride powder, 8 parts of modified sericite B, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 50 parts of nitrile rubber, 1.4 parts of stearic acid, 4 parts of zinc oxide, and 2 parts of antioxidant RD at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material B; Step 3: Preparation of composite materials: S1: Rubber-plastic material A and rubber-plastic material B are stacked alternately to obtain an unfoamed multilayer composite material with a total of 23 layers and the outermost layer being rubber-plastic material B. S2: Place the unfoamed multilayer composite material into the mold, with the foaming expansion gap being 25% of the total thickness of the unfoamed multilayer composite material; use a flat vulcanizing machine at 160℃ and a pressure of 12MPa for 12 minutes to foam and vulcanize, obtaining a multilayer composite rubber-plastic foam insulation material with a thickness of 10mm.
[0031] Comparative Example 5: Based on Example 1, rubber and plastic material A was directly prepared into a single-layer foam material: Step 1: Preparation of Rubber-Plastic Material A: Mix 40 parts of polyvinyl chloride powder, 10 parts of modified sericite A, 2.4 parts of calcium-zinc composite stabilizer, 1.2 parts of zinc stearate, and 15 parts of plasticizer dioctyl phthalate evenly to obtain PVC material; mix 60 parts of nitrile rubber, 1.4 parts of stearic acid, and 4 parts of zinc oxide at 160℃ and 60r / min for 4min to obtain NBR material; add PVC material and continue mixing for 12min, cool to room temperature, add 6 parts of foaming agent azodicarbonamide, 2.7 parts of vulcanizing agent sulfur, 1.6 parts of accelerator CZ, and 0.5 parts of accelerator TMTD, mix evenly at 60℃ and 20r / min, and sheet to obtain rubber-plastic material A; Step 2: Preparation of composite materials: S1: Place rubber and plastic material A into the mold, and leave a gap of 25% of the total thickness of the unfoamed material for foaming expansion; use a flat vulcanizing machine at 160℃ and 12MPa pressure for 12 minutes to foam and vulcanize, and obtain a composite rubber and plastic foam insulation material with a thickness of 10mm.
[0032] Performance testing: (1) According to GB / T 528, vulcanized samples of rubber-plastic material A and rubber-plastic material B were prepared according to the methods of Examples 1-3 and Comparative Examples 1-3 respectively, and the mechanical properties were tested using a universal testing machine; the sample thickness was 2 mm and the tensile rate was 50 mm / min; (2) According to GB / T 3512, the rubber-plastic material A and rubber-plastic material B samples of Examples 1-3 and Comparative Examples 1-3 were aged at 100℃ for 3 days, and the tensile strength was measured again and the tensile strength retention rate was calculated; (3) According to GB / T 10294, the thermal conductivity of Examples 1-3 and Comparative Examples 1-5 was tested using a thermal conductivity meter; the experimental data are shown in the table below.
[0033]
[0034] Conclusions: As shown in the table above, in Comparative Example 1, modified sericite A was only thiolized, and the anti-aging agent was introduced in a free form. Tensile strength was slightly improved, but retention rate decreased significantly. Simultaneously, thermal conductivity was slightly improved, possibly because the increased thiol content on the sericite surface makes cross-linking easier, thus increasing strength. However, the overall cell structure stability decreased, resulting in reduced thermal insulation performance. In Comparative Example 2, the rubber-plastic material A was prepared using a 50:50 rubber-plastic ratio, which improved tensile strength but decreased thermal insulation performance. In Comparative Example 3, modified sericite B was prepared using isopropyltriisostearoyl titanate. The modified material showed a decrease in both tensile strength and retention rate. This was because the long chain of isopropyl triisostearoyl titanate had significant steric hindrance, which reduced interfacial properties. In Comparative Example 4, the total number of layers in the preparation of the multilayer composite rubber-plastic foam insulation material was set to 23. The thermal conductivity increased, but the insulation performance decreased. This was because the dense layer had an excessively strong clamping and restraining effect, which affected the formation of bubbles. In Comparative Example 5, rubber-plastic material A was directly prepared into a single-layer foam material. Due to the lack of constraint from rubber-plastic material B during the foaming process, the cell distribution was relatively uneven, and there were cell wall ruptures, which led to an increase in thermal conductivity.
[0035] In summary, the multilayer composite rubber-plastic foam material prepared by this invention has good mechanical properties and anti-aging properties. At the same time, the alternating multilayer composite structure of the two materials has better thermal insulation performance compared with a single material.
[0036] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a multilayer composite rubber-plastic foamed thermal insulation material, characterized in that: Includes the following steps: S1: Alternately stack rubber-plastic material A and rubber-plastic material B to obtain an unfoamed multilayer composite material with rubber-plastic material B as the outermost layer; S2: Place the unfoamed multilayer composite material into a mold, and hot-press it to foam and vulcanize it to obtain a multilayer composite rubber-plastic foam insulation material. The raw materials of the rubber-plastic material A include nitrile rubber / polyvinyl chloride with a rubber-plastic ratio of 60:40, modified sericite A, and a foaming agent; the raw materials of the rubber-plastic material B include nitrile rubber / polyvinyl chloride with a rubber-plastic ratio of 50:50, modified sericite B, and an antioxidant. The modified sericite A was prepared from N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-modified thiolated sericite; the modified sericite B was prepared from isopropyltris(dioctylpyrophosphate)titanate and white oil-modified sericite.
2. The method for preparing a multi-layer composite rubber-plastic foamed thermal insulation material according to claim 1, characterized in that: The rubber and plastic material A comprises the following raw materials, by weight: 60 parts nitrile rubber, 40 parts polyvinyl chloride, 8-12 parts modified sericite A, 2-3 parts calcium-zinc composite stabilizer, 1-1.5 parts zinc stearate, 15-20 parts plasticizer, 1-2 parts stearic acid, 3-5 parts zinc oxide, 4-8 parts foaming agent, 2-3 parts vulcanizing agent, 1.5-2 parts accelerator CZ, and 0.5-1 part accelerator TMTD.
3. The method for preparing a multilayer composite rubber-plastic foamed thermal insulation material according to claim 2, characterized in that: The preparation method of the modified sericite A includes the following steps: (1) Sericite is ultrasonically dispersed in an ethanol aqueous solution, 1~1.5 parts of mercaptopropyltrimethoxysilane are added dropwise, and the mixture is stirred at 40~50℃ for 5~8h. The mixture is then filtered, washed, and dried to obtain mercapto-modified sericite. (2) Thiolized sericite and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine were added to acetone and ultrasonically dispersed evenly. The mixture was stirred at 20-25°C for 10-12 hours, then vacuumed for 1-2 hours, filtered, washed, and dried to obtain modified sericite A.
4. The method for preparing a multi-layer composite rubber-plastic foamed thermal insulation material according to claim 3, characterized in that: The mercaptolated sericite comprises the following raw materials, in parts by mass: 8-10 parts sericite, 100-150 parts aqueous ethanol solution, and 1-1.5 parts mercaptopropyltrimethoxysilane; The modified sericite A comprises the following raw materials, in parts by mass: 8-10 parts mercapto-modified sericite and 3-6 parts N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine.
5. The method for preparing a multilayer composite rubber-plastic foamed thermal insulation material according to claim 1, characterized in that: The rubber and plastic material B comprises the following raw materials, by weight: 50 parts nitrile rubber, 50 parts polyvinyl chloride, 5-10 parts modified sericite B, 2-3 parts calcium-zinc composite stabilizer, 1-1.5 parts zinc stearate, 15-20 parts plasticizer, 1-2 parts stearic acid, 3-5 parts zinc oxide, 1-3 parts antioxidant RD, 2-3 parts vulcanizing agent, 1.5-2 parts accelerator CZ, and 0.5-1 part accelerator TMTD.
6. The method for preparing a multi-layer composite rubber-plastic foamed thermal insulation material according to claim 5, characterized in that: The preparation method of the modified sericite B includes the following steps: adding sericite, isopropyl tris(dioctyl pyrophosphoryloxy) titanate, and white oil into a high-speed mixer and mixing for 5-10 minutes to obtain modified sericite B.
7. The method for preparing a multi-layer composite rubber-plastic foamed thermal insulation material according to claim 6, characterized in that: The modified sericite B comprises the following raw materials, by mass: 8-10 parts sericite, 0.1-0.3 parts isopropyl tris(dioctyl pyrophosphate) titanate, and 0.1-0.3 parts white oil.
8. The method for preparing a multilayer composite rubber-plastic foamed thermal insulation material according to claim 1, characterized in that: The thickness ratio of the rubber-plastic material A to the rubber-plastic material B is 1 to 3:1; the total number of layers of the unfoamed multilayer composite material is 9, 11, 13, 15, 17 or 19 layers.
9. The method for preparing a multi-layer composite rubber-plastic foamed thermal insulation material according to claim 1, characterized in that: During the hot-pressing foaming vulcanization process, the foaming expansion gap is 10-30% of the total thickness of the unfoamed multilayer composite material; the vulcanization temperature is 160-170℃, the pressure is 10-15MPa, and the time is 5-15min; the thickness of the multilayer composite rubber-plastic foam insulation material is 5-10mm.
10. The multilayer composite rubber-plastic foamed thermal insulation material prepared by the method according to any one of claims 1 to 9.