A polyester foam sandwich composite panel, its preparation method and application

Abstract

This invention belongs to the field of composite material technology, specifically relating to a polyester foam sandwich composite board, its preparation method, and its application. The polyester foam sandwich composite board comprises the following components by weight: core layer: 70-90 parts polyester, 2-10 parts foaming agent, 5-10 parts inorganic filler, 2-8 parts chain extender, 0.5-2 parts stabilizer, and 0.5-1 part dispersant; skin layer: 73-90 parts polyester, 0.5-1 part antioxidant, 9-23 parts hardness modifier, and 0.3-3.5 parts flow modifier. The composite material obtained by this invention has high surface hardness and skin smoothness, as well as high closed-cell ratio, compression performance, and nail-holding force, effectively solving the defects of high density, heavy weight, and high cost inherent in rigid non-foamed plastic boards.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to a polyester foam sandwich composite board, its preparation method, and its application. Background Technology

[0002] As the national economy transforms towards high-quality development and people's living standards continue to improve, small and medium-sized enterprises are also shifting towards low-carbon and environmentally friendly models under the guidance of social policies. In the fields of building materials, transportation interiors, and other decorative building materials, more and more companies are advocating the replacement of wood with plastic, especially multi-functional building material boards that integrate flame retardancy, heat insulation, and sound insulation, which are becoming increasingly popular.

[0003] Currently, most plastic sheets sold on the market are single-layer foamed sheets or single-layer rigid non-foamed sheets. Although foamed plastic sheets are lightweight, they have low surface hardness, poor flatness, and poor surface physical rigidity. They cannot withstand strong impacts and friction, are easily worn, and have a rough, poor-smooth surface. Even if a glossy effect can be achieved through painting or other surface processing techniques, their color is still poor. Rigid non-foamed plastic sheets have high hardness and can withstand strong impacts and friction. A smooth surface can also be achieved through surface processing, and the color is good after painting. However, their high density often makes them heavy and inconvenient to use. To improve the mechanical strength and thermal properties of plastic sheets, sandwich composite materials have emerged. Sandwich composite materials typically use high-strength thin sheets as the face sheet and lightweight, thick foam boards as the core material. The thicker core foam board in the middle keeps the top and bottom face sheets away from the neutral plane, greatly increasing the structural load-bearing capacity of the composite material and strengthening the bending and compressive strength of the composite sheet.

[0004] Existing core foam board materials include polyester, polyurethane, polyvinyl chloride, polypropylene, and polystyrene. Among them, polyurethane foam (PET) stands out from other foam materials due to its superior environmental friendliness, recyclability, good processability, excellent fatigue resistance, and superior mechanical properties. It is also easily bonded and infused with various resins, suitable for various processes, and does not easily deform at high temperatures. However, it still has the following drawbacks: First, the formulation and proportions of the raw materials used in polyurethane foam boards are not conventionally defined, often resulting in a chaotic and unstable mix of raw materials and proportions. Second, the physical stability of the board material is often poor, and the resulting polyester foam boards exhibit inferior mechanical properties, Shore hardness, heat distortion temperature, and nail-holding power, making it difficult to meet practical needs and limiting its application. Third, at low temperatures, especially below 10°C, the foaming power of polyurethane foam materials decreases significantly. Therefore, there is an urgent need to develop a polyester composite material that is lightweight while possessing good mechanical properties, hardness, and heat resistance. Summary of the Invention

[0005] This invention aims to provide a polyester foam sandwich composite board, its preparation method, and its application. The composite material obtained by this invention has high surface hardness and surface smoothness, as well as high closed-cell ratio, compression performance, and nail-holding force, thus solving the defects of plastic foam boards such as low surface hardness, poor flatness, and poor heat resistance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a polyester foam sandwich composite board, comprising the following components by weight:

[0007] Core layer: 70-90 parts polyester, 2-10 parts foaming agent, 5-10 parts inorganic filler, 2-8 parts chain extender, 0.5-2 parts stabilizer, 0.5-1 part dispersant;

[0008] Skin layer: 73-90 parts polyester, 0.5-1 part antioxidant, 9-23 parts hardness modifier, 0.3-3.5 parts flow modifier.

[0009] Preferably, the polyester foam sandwich composite panel comprises the following components in parts by weight:

[0010] Core layer: 90 parts polyester, 2 parts foaming agent, 5 parts inorganic filler, 2 parts chain extender, 0.5 parts stabilizer, 0.5 parts dispersant;

[0011] Skin: 80 parts polyester, 0.5 parts antioxidant, 16 parts hardness modifier, 3.5 parts flow modifier.

[0012] Preferably, the structure of the polyester foam sandwich composite panel includes, from top to bottom, an upper skin layer, a core layer, and a lower skin layer, wherein the thickness of the upper and lower skin layers is 0.2–1 mm, and the thickness of the core layer is 10–20 mm.

[0013] Preferably, the polyester components used in the core layer and the outer layer of the polyester foam sandwich composite board are the same.

[0014] Preferably, the polyester foam sandwich composite panel includes at least one of the following (1) to (2):

[0015] (1) The density of the polyester foam sandwich composite board is 200-400 kg / m³. 3 ;

[0016] (2) The mass ratio of the foaming agent, inorganic filler and chain extender is (1-5):(3-5):(1-3).

[0017] Preferably, the polyester foam sandwich composite panel includes at least one of the following (1) to (6):

[0018] (1) The polyester includes at least one of PET, rPET, PETG, APET, PBT, PTT, PLA, PBAT, PGA, PHA, PCL, PCT, PCTG, and PC;

[0019] (2) The foaming agent includes at least one of liquid carbon dioxide, n-pentane, octane, cyclopentane, n-hexane, liquid nitrogen, hydrofluorocarbon, HFO-1233zd, and sodium bicarbonate;

[0020] (3) The inorganic filler includes at least one of the following: long-chain linear saturated carboxylate sodium salt, magnesium oxide, carbon black, calcium carbonate, talc, montmorillonite, diatomaceous earth, magnesium carbonate, N-butylpyridine potassium salt, fly ash, fiberglass waste residue, and slag.

[0021] (4) The chain extender includes at least one of the following: copolymers containing epoxy functional groups, polymers with polyisocyanate functional groups, polymers with polyimide functional groups, polymers with polyanhydride groups, and polymers with polyhydroxy groups;

[0022] (5) The stabilizer includes at least one of trimethyl phosphate, triethyl phosphoroacetate, and triphenyl phosphate;

[0023] (6) The dispersant includes at least one of stearate, ethylene bis-stearamide, and polyethylene wax.

[0024] This invention incorporates inorganic fillers into the core layer, which act as nucleating agents and crystallization modifiers in the formulation system. The inorganic fillers interact with the foaming agent and chain extender, forming heterogeneous nucleation during the foaming process, resulting in numerous and uniform foaming points. Simultaneously, they effectively prevent gas escape that could cause cell rupture and merging, leading to denser cells and further improving the closed-cell ratio, compressive strength, and tensile strength of the core layer. Furthermore, the inorganic fillers enhance the crystallinity of polyester polymers in the formulation system, refining grain size and effectively strengthening the filling effect. This improves the rigidity, compressive strength, and nail-holding power of the core layer. Moreover, it is environmentally friendly, enabling the recycling and reuse of fly ash from coal-fired power plants, fiberglass product (such as wind turbine blades) waste, and industrial slag, truly realizing the green, low-carbon, and circular development of solid waste.

[0025] The addition of the dispersant in this invention can reduce the internal shear heat of the melt, prevent material degradation, improve the dispersibility of a large amount of filler added to the matrix, stabilize the mechanical properties of each section of the foam layer, keep the holding force value within ±5%, and prevent the agglomeration of a large amount of filler, which can cause large bubbles or bubble rupture.

[0026] Preferably, the polyester foam sandwich composite panel includes at least one of the following (1) to (3):

[0027] (1) The antioxidants include at least one of hindered phenolic antioxidants, aromatic amine antioxidants, and sulfur antioxidants;

[0028] (2) The hardness modifier includes at least one of hard resin, inorganic filler, and reinforcing fiber;

[0029] (3) The flow modifier includes at least one of alkyl polyacids / alcohols / amines, low molecular weight polyesters, olefin polymers, branched or hyperbranched polymers, and nano salts.

[0030] In this invention, the hardness modifier added to the surface component works together with other components to promote grain refinement and improve crystallization performance, thereby effectively improving the overall strength, rigidity and impact resistance of the obtained polyester foam sandwich composite board.

[0031] The addition of the flow modifier in this invention enables the skin component to have good flowability and mechanical properties during the preparation process. At the same time, it can reduce surface friction, improve the wettability of the skin component with other components such as polyester, and effectively improve the surface smoothness and flatness of the obtained material. In addition, the addition of the flow modifier can also improve the compatibility of the polyester substrate, hardness modifier and core layer in the polyester foam sandwich composite board, and increase the coating adhesion between the upper and lower skin layers and the middle core layer.

[0032] Preferably, the polyester foam sandwich composite panel includes at least one of the following (1) to (4):

[0033] (1) The rigid resin includes at least one of PS, PMMA and ABS;

[0034] (2) The Mohs hardness of the inorganic filler is ≥5;

[0035] (3) The inorganic filler includes at least one of glass microspheres, porous quartz powder, clay, silica, titanium dioxide, and calcium carbonate;

[0036] (4) The reinforcing fiber includes at least one of glass fiber, carbon fiber, and basalt fiber.

[0037] A method for preparing the polyester foam sandwich composite panel includes the following steps:

[0038] S1. Mix the dried polyester, inorganic filler, chain extender, stabilizer and dispersant, melt and shear, add foaming agent, and mix thoroughly to obtain material 1;

[0039] S2. Mix all components of the leather raw material and melt-shear to obtain material 2;

[0040] S3. Material 1 and Material 2 are extruded simultaneously through a three-channel co-extrusion die and a flat die template to form the upper and lower surface layers A and the foamed core layer B in one step. The foamed core layer B and the upper and lower surface layers A melt are extruded and heat-sealed to obtain a polyester sandwich foam composite board.

[0041] Preferably, the preparation method includes at least one of the following (1) to (3):

[0042] (1) The drying temperature of the polyester is 150-180℃ and the drying time is 4-8h;

[0043] (2) The melting shearing temperature in step S1 is 200-280℃ and the shearing speed is 130-150r / min;

[0044] (3) The melting shearing temperature in step S2 is 220-290℃ and the shearing speed is 100-120r / min.

[0045] This invention uses polyester as the base material and prepares composite boards through a three-layer co-extrusion technology. Its performance effectively overcomes the defects of foamed and non-foamed plastic boards, such as low surface hardness, poor flatness, and heavy weight. The three-layer co-extruded foam board of this invention uses two identical extruders and one single-screw extruder as foaming equipment. The materials are blended separately and then simultaneously extruded through a three-channel co-extrusion die and a flat die, forming a non-foamed upper and lower surface layer A and a foamed core layer B in a one-step molding process. Hardness modifiers and flow modifiers are added to the surface layer components, resulting in a smooth surface and excellent hardness of the polyester composite board. Specific core material components improve the density, mechanical strength, and foamability of the polyester foam board. The surface material and core material are extruded and bonded in the molten polyester state through specific flow channels, eliminating the need for impregnation, lamination, or other processing steps on the polyester foam board. Furthermore, the core material and surface material have strong bonding strength and stable mechanical properties, which is beneficial for subsequent material applications.

[0046] An application of the aforementioned polyester foam sandwich composite panel in the fields of building (insulation panels), vehicle and ship manufacturing (automotive interiors), and home furnishing panels.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) This invention uses a three-layer co-extrusion foaming technology. Through the properties of the polyester material itself and the interaction between the added inorganic fillers, foaming agents, chain extenders, hardness modifiers, flow modifiers and other additives, the composite material can achieve high surface hardness and surface smoothness. This solves the common problems of foam products having rough and easily worn surfaces, low hardness, unevenness, smoothness and color, poor surface physical rigidity, and inability to resist strong impact and friction.

[0049] (2) The polyester foam sandwich composite board prepared by this invention is 50-80% lighter than pure plastic boards, and does not contain harmful substances such as benzene and formaldehyde. It is waterproof, moisture-proof, mildew-proof, sound-insulating and noise-reducing, avoiding environmental pollution and fire hazards. It can replace PVC, boards, and artificial boards (MDF, particleboard, plywood), and is widely used in construction, vehicle and ship manufacturing, home building materials, decoration, renovation, advertising production, exhibition signs, urban environmental protection, tourism and other industries. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the structure of the polyester foam sandwich composite panel obtained in an embodiment of the present invention.

[0051] Figure 2 This is a schematic diagram of the equipment structure for the polyester foam sandwich composite panel of the present invention.

[0052] Figure 3 This is a cross-sectional view of the die head used in the preparation process of the polyester foam sandwich composite board of the present invention.

[0053] Figure 4 This is a picture of the finished polyester foam sandwich composite board obtained in an embodiment of the present invention.

[0054] In the diagram, 1 is the upper skin layer; 2 is the core layer; 3 is the lower skin layer; 4 is the twin-screw extruder; 5 is the special pipe for transporting melt A; 6 is the special pipe for transporting melt B; 7 is the specific die; and 8 is the twin-screw extruder. Detailed Implementation

[0055] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0056] Unless otherwise specified, the experimental methods used in the examples and comparative examples are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0057] The raw materials used in the examples and comparative examples are shown in Table 1.

[0058] Table 1

[0059]

[0060]

[0061] Examples 1-7 and Comparative Examples 1-6

[0062] The components and weight parts of the polyester foam sandwich composite panels of Examples 1-7 and Comparative Examples 1-6 are shown in Tables 2 and 3.

[0063] The preparation methods of the polyester foam sandwich composite panels of Examples 1-7 and Comparative Examples 1-6 include the following steps:

[0064] The polyester was dried at 160℃ for 6 hours. The dried polyester was then added to the main feed inlet of a two-stage screw extruder. The screw heating zones 1-8 were set to temperatures of 200℃, 250℃, 265℃, 270℃, 280℃, 275℃, 270℃, and 265℃, respectively, with the die head temperature set at 225℃. The screw speed was set at 145 r / min. The polyester was fully melted and sheared in the screw. Inorganic fillers, chain extenders, stabilizers, and dispersants were added through the side feed inlet. The foaming agent was injected into the melt from heating zone 4. The mixture was thoroughly mixed and then passed through a static mixer and a special pipeline in a specific environment. Polyester core foam board is prepared by extrusion and foaming at the die head. Simultaneously, polyester, hardness modifier, flow modifier, and antioxidant are added to the feed port of another twin-screw extruder. The heating zones 1-5 are set to temperatures of 220℃, 260℃, 280℃, 290℃, and 265℃, respectively, and the die head temperature is 225℃. After melt shearing, the screw speed is set to 120 r / min, and the material is conveyed to a special pipeline through the screw. It converges with the polyester core melt at a specific die head and is extruded from the die head at the same time. The core material and the face material melt at the die head are extruded and heat-bonded to form a polyester foam sandwich composite board.

[0065] Table 2 shows the component amounts (parts by weight) in the examples.

[0066]

[0067]

[0068] Table 3. Component dosage (parts by weight) in the comparative examples

[0069]

[0070] Comparative Example 7

[0071] Compared with Example 3, the only difference in this comparative example is that the skin layer component is replaced with an equal amount of core layer component, and the three-layer structure of the resulting polyester foam sandwich composite board is composed of the core layer component.

[0072] The preparation method is described in Example 3.

[0073] Performance testing

[0074] The polyester foam sandwich composite panels prepared in Examples 1-7 and Comparative Examples 1-7 were trimmed and cut into strips for mechanical and thermal property testing. The test methods and standards are described below, and the experimental results are shown in Table 4.

[0075] Density: Tested according to standard ISO 844-2004.

[0076] Compressive strength: According to ISO 844-2004 standard for testing the compressive properties of rigid foamed plastics, the standard value is ≥2.5MPa.

[0077] Tensile strength: According to ASTM C297-2004, the tensile strength of sandwich structures in planar plane is determined, and the standard value is tensile strength ≥4MPa.

[0078] Shore hardness: According to GB 2411-1980, the standard value for a surface with high Shore hardness is Shore hardness ≥75D.

[0079] Heat distortion temperature: Tested according to standard ASTM D648-2018, the standard value is heat distortion temperature ≥117℃.

[0080] Screw holding force: Tested according to GBT17657-2013 Standard Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels. The standard value is ≥650N for screw holding force of composite board.

[0081] Table 4 Performance Test Results

[0082]

[0083]

[0084] The data in Table 4 show that the polyester foam sandwich composite board prepared in the embodiments of the present invention has good compressive strength and tensile strength, and the prepared composite board can achieve high surface hardness, heat distortion temperature and nail holding force.

[0085] In Comparative Example 1, the amount of polyester component added to the core layer was too small, resulting in poor mechanical properties of the resulting polyester foam sandwich composite board. Comparative Examples 2 and 3 lacked foaming agents or inorganic fillers, preventing them from working together with chain extenders and other components, further reducing the compressive and tensile strength of the polyester foam sandwich composite board. In Comparative Example 4, the mass ratio of foaming agent, inorganic filler, and chain extender was unsuitable, resulting in composite boards with mechanical properties inferior to the examples. In Comparative Example 5, the amount of flow modifier added was excessive, failing to improve the compatibility between the core and skin layers and negatively impacting the surface hardness and other properties of the resulting composite board. In Comparative Example 6, the polyester component used in the core layer differed from that used in the skin layer, resulting in composite boards with inferior mechanical properties, surface hardness, heat distortion temperature, and nail-holding power compared to the examples. In Comparative Example 7, the composite board consisted only of a single core layer, exhibiting mechanical and thermal properties inferior to the examples.

[0086] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A polyester foam sandwich composite panel, characterized in that, Includes the following components by weight: Core layer: 70-90 parts polyester, 2-10 parts foaming agent, 5-10 parts inorganic filler, 2-8 parts chain extender, 0.5-2 parts stabilizer, 0.5-1 part dispersant; Skin layer: 73-90 parts polyester, 0.5-1 part antioxidant, 9-23 parts hardness modifier, 0.3-3.5 parts flow modifier; The inorganic filler in the core layer includes at least one of magnesium oxide and calcium carbonate. The chain extender includes at least one of the following: copolymers containing epoxy functional groups, polymers with polyisocyanate functional groups, polymers with polyimide functional groups, polymers with polyanhydride groups, and polymers with polyhydroxy groups. The hardness modifier includes at least one of hard resin and inorganic filler; the hard resin includes at least one of PS, PMMA, and ABS; the inorganic filler in the skin layer includes at least one of glass microspheres, porous quartz powder, silica, titanium dioxide, and calcium carbonate, and the Mohs hardness of the inorganic filler in the skin layer is ≥5. The flow modifier is pentaerythritol tristearate; The core layer and the outer layer of the polyester foam sandwich composite board are made of the same polyester component, PET.

2. The polyester foam sandwich composite panel as described in claim 1, characterized in that, Includes the following components by weight: Core layer: 90 parts polyester, 2 parts foaming agent, 5 parts inorganic filler, 2 parts chain extender, 0.5 parts stabilizer, 0.5 parts dispersant; Skin: 80 parts polyester, 0.5 parts antioxidant, 16 parts hardness modifier, 3.5 parts flow modifier.

3. The polyester foam sandwich composite panel as described in claim 1, characterized in that, The structure of the polyester foam sandwich composite panel includes, from top to bottom, an upper skin layer, a core layer, and a lower skin layer. The thickness of the upper and lower skin layers is 0.2~1mm, and the thickness of the core layer is 10~20mm.

4. The polyester foam sandwich composite panel as described in claim 1, characterized in that, The density of the polyester foam sandwich composite panel is 200-400 kg / m³. 3 .

5. The polyester foam sandwich composite panel as described in claim 1, characterized in that, It must include at least one of the following (1) to (3): (1) The foaming agent includes at least one of liquid carbon dioxide, n-pentane, octane, cyclopentane, n-hexane, liquid nitrogen, hydrofluorocarbon, HFO-1233zd, and sodium bicarbonate; (2) The stabilizer includes at least one of trimethyl phosphate, triethyl phosphoroacetate, and triphenyl phosphate; (3) The dispersant includes at least one of stearate, ethylene bis-stearamide, and polyethylene wax.

6. The polyester foam sandwich composite panel as described in claim 1, characterized in that, The antioxidant includes at least one of hindered phenolic antioxidants, aromatic amine antioxidants, and sulfur antioxidants.

7. A method for preparing a polyester foam sandwich composite panel as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Mix the dried polyester, inorganic filler, chain extender, stabilizer and dispersant, melt and shear, add foaming agent, and mix thoroughly to obtain material 1; S2. Mix all components of the leather raw material and melt-shear to obtain material 2; S3. Material 1 and Material 2 are extruded simultaneously through a three-channel co-extrusion die and a flat die template to form the upper and lower surface layers A and the core layer B in one step. The core layer B and the melt of the upper and lower surface layers A are extruded and heat-sealed to obtain a polyester sandwich foam composite board.

8. The preparation method according to claim 7, characterized in that, It must include at least one of the following (1) to (3): (1) The drying temperature of the polyester in step S1 is 150~180℃ and the drying time is 4~8h; (2) The melting shearing temperature in step S1 is 200~280℃, and the shearing speed is 130~150r / min; (3) The melting shearing temperature in step S2 is 220~290℃ and the shearing speed is 100~120r / min.

9. The application of a polyester foam sandwich composite panel as described in any one of claims 1 to 6 in the fields of construction and vehicle / ship manufacturing.

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