EPP product surface treatment method and equipment

Abstract

The invention relates to the technical field of EPP product surface treatment, in particular to an EPP product surface treatment method and device.The treatment method comprises the following steps that S1, a membrane material is placed on an EPP product; and S2, the membrane material is attached to the surface of the EPP product through an adsorption attaching technology, and surface treatment of the EPP product is achieved. According to the EPP product surface treatment method provided by the invention, the EPP product is coated through the film material under the adsorption effect, so that the film material adapts to the outer contour of the EPP product under the adsorption effect, the EPP product is completely attached without bubbles and gaps, the attaching effect is not influenced by the shape of the EPP product, and the special-shaped EPP product can be coated with a film.

Description

Technical Field

[0001] This invention relates to the field of EPP product surface treatment technology, and in particular to a method and equipment for EPP product surface treatment. Background Technology

[0002] EPP products are essentially a type of foam material, and it is difficult to meet the needs of various scenarios simply by improving the raw materials of EPP. EPP has a very wide range of applications and is widely used in transportation, industrial turnover, cold chain logistics, product packaging, electronics, consumer leisure, construction, and military industries.

[0003] Different scenarios present different functional requirements. For example, in the cold chain distribution of medicines or food, the surface needs to be impermeable; in the recycling process of new energy battery packaging, it is necessary to prevent the product surface from shedding debris due to friction and increase its abrasion resistance; EPP sheets have the advantage of lightweighting when replacing furniture boards, but the surface hardness of the sheets needs to be improved; consumer products such as children's toys, surfboards, and 3C packaging materials need to display product information on the surface, but because the traditional solution for EPP products is to integrally mold them on a mold, it is impossible to display graphic information in multiple colors simultaneously.

[0004] Therefore, in practical applications, many EPP products require the coating of functional films on their surfaces to achieve purposes such as waterproofing, oil resistance, abrasion resistance, improved printability, or enhanced surface hardness. Traditional surface coating processes typically rely on general-purpose coating equipment, which is often designed for flat or regularly curved workpieces. This equipment achieves adhesion between the film and the substrate through uniform hot pressing or adhesive bonding. However, since EPP products are often irregularly shaped, directly applying such general-purpose equipment to irregularly shaped EPP products can lead to problems. The complex, discontinuous curved surfaces and sharp angles on the surface of these irregularly shaped parts make it difficult for the pressing mechanism of the equipment to adapt to the dynamic changes in their geometry. This can easily result in the film material being suspended, wrinkled, or poorly adhered in uneven areas, severely affecting the appearance quality and protective performance.

[0005] Therefore, how to coat irregularly shaped EPP products is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] To address the problem of difficulty in coating EPP products in existing technologies, this invention provides a surface treatment method for EPP products. This EPP product surface treatment equipment uses a traction system, an adsorption bonding system, and a pressing system in combination to achieve coating of irregularly shaped EPP products, thus solving the problem of difficulty in coating EPP products in existing technologies.

[0007] The technical solution adopted by this invention to solve its technical problem is: A surface treatment method for EPP products includes the following steps: S1: Place the membrane material on top of the EPP product; S2: The membrane material is bonded to the surface of the EPP product through an adsorption bonding process to achieve surface treatment of the EPP product.

[0008] Optionally, the process of attaching the membrane material to the surface of the EPP product by adsorption bonding includes: preheating and softening the membrane material, pressing the membrane material onto the surface of the EPP product, and using negative pressure suction to attach the membrane material to the surface of the EPP product.

[0009] Optionally, the membrane material includes an adhesive layer and at least one functional layer laminated on top of the adhesive layer.

[0010] Optionally, the melting point of the adhesive layer is in the range of 45-130°C.

[0011] Another object of the present invention is to provide an EPP product surface treatment device, which treats the surface of EPP products by the EPP product surface treatment method described above; the EPP product surface treatment device includes a feeding traction device, an adsorption bonding system and a receiving traction device arranged sequentially adjacent to each other; the receiving traction device and the feeding traction device drive the film material through the adsorption bonding system.

[0012] Optionally, the adsorption bonding system includes a hot air system, a pressing system, and an adsorption system arranged sequentially from top to bottom; the membrane material is located between the pressing system and the adsorption system.

[0013] Optionally, the adsorption system includes an adsorption chamber and a mold mounted on the adsorption chamber; the adsorption chamber is connected to a vacuum system.

[0014] Optionally, a sealing strip is provided between the mold and the adsorption chamber.

[0015] Optionally, it also includes a cutting system located between the adsorption bonding system and the material collection and traction device.

[0016] Optionally, the cutting system includes a die and a press (32) disposed above the die.

[0017] The beneficial effects of this invention are: The EPP product surface treatment method provided by the present invention utilizes adsorption to coat the EPP product with a membrane material, so that the membrane material adapts to the outer contour of the EPP product under adsorption, achieving a bubble-free and seamless complete adhesion of the EPP product. The adhesion effect is not affected by the shape of the EPP product, and it can achieve coating of irregularly shaped EPP products. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Figure 1 This is a simplified structural diagram of the EPP product surface treatment equipment of the present invention. In the diagram: 1-feeding traction device; 2-adsorption bonding system; 21-hot air system; 22-pressing system; 23-adsorption system; 231-adsorption chamber; 232-mold; 233-sealing strip; 3-cutting system; 31-die; 32-press; 4-receiving traction device; 5-film material. Detailed Implementation

[0020] The present invention will now be described in further detail. The embodiments described below are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] To address the problem of difficulty in coating irregularly shaped EPP products in existing technologies, this invention provides a surface treatment method for EPP products, which includes the following steps: S1: Place membrane material 5 on top of the EPP product; S2: The membrane material 5 is bonded to the surface of the EPP product through an adsorption bonding process to achieve surface treatment of the EPP product.

[0023] Since the present invention achieves the coating of EPP products by the membrane material 5 through adsorption, the membrane material 5 can achieve a bubble-free and seamless complete adhesion with the EPP products under the adsorption effect. The adhesion effect is not affected by the shape of the EPP products, and it can achieve the coating of irregularly shaped EPP products.

[0024] The EPP product surface treatment method provided by the present invention utilizes adsorption to coat the EPP product with a membrane material 5, so that the membrane material 5 adapts to the outer contour of the EPP product under adsorption, achieving a bubble-free and seamless complete adhesion of the EPP product. The adhesion effect is not affected by the shape of the EPP product, and it can achieve coating of irregularly shaped EPP products.

[0025] Specifically, to ensure the coating effect, the present invention preferably uses an adsorption bonding process to bond the membrane material 5 to the surface of the EPP product, including: preheating and softening the membrane material 5, pressing the membrane material 5 to the surface of the EPP product, and using negative pressure suction to bond the membrane material 5 to the surface of the EPP product.

[0026] By preheating and softening the membrane material 5, the membrane material 5 is made to have good extensibility and adhesion fluidity; by applying pressure through pressing, the softened membrane material 5 is tightly attached to the surface of the EPP product; further, by using negative pressure suction, it is ensured that the membrane material 5 and the EPP product are completely bonded without air bubbles or gaps.

[0027] To ensure the coating effect, the present invention preferably includes an adhesive layer and at least one functional layer composited on the adhesive layer; and further preferably the melting point of the adhesive layer is in the range of 45-130°C.

[0028] Another object of the present invention is to provide an EPP product surface treatment apparatus, which treats the surface of EPP products using the EPP product surface treatment method described above; see also Figure 1 As shown, the equipment includes a feeding traction device 1, an adsorption bonding system 2, and a receiving traction device 4 arranged sequentially adjacent to each other. The adsorption bonding system 2 is used to bond the corresponding film material 5 to the surface of the EPP product through an adsorption bonding process. The feeding traction device 1 and the receiving traction device 4 constitute a film material traction system for transferring the film material 5. The traction can be manually controlled or intermittently automated to ensure that the film is pulled to the corresponding position. Both the feeding traction device 1 and the receiving traction device 4 can be selected from existing traction devices suitable for transferring film materials. During use, the receiving traction device 4 and the feeding traction device 1 work together to drive the film material 5 continuously through the adsorption bonding system 2, thereby achieving functional coating treatment on the surface of the EPP product.

[0029] Specifically, during the operation of the EPP product surface treatment equipment, the EPP product to be coated is placed in the adsorption and bonding system 2. The corresponding film material 5 is driven through the adsorption and bonding system 2 by the feeding traction device 1 and the receiving traction device 4, and passes over the EPP product. Under the adsorption effect of the adsorption and bonding system 2, the film material 5 is strongly adsorbed and tightly adhered to the surface of the EPP product, thereby achieving the coating of the EPP product.

[0030] Since the present invention achieves the coating of EPP products by the membrane material 5 through adsorption, the membrane material 5 can achieve a bubble-free and seamless complete adhesion with the EPP products under the adsorption effect. The adhesion effect is not affected by the shape of the EPP products, and it can achieve the coating of irregularly shaped EPP products.

[0031] To ensure the coating effect, the preferred EPP product molding mold and process of this invention are as follows: 1) The air plugs are pinhole air plugs with a hole diameter of 0.25-0.45mm, and the distance between the air plugs is controlled between 0.6-1.5mm; 2) The mold surface must be textured, preferably with a texture depth controlled between 0.2-0.5mm; 3) The steam pressure control accuracy of the preferred EPP molding equipment is ±0.15bar, and the steam pressure of the external pipeline of the molding machine is controlled at 0.75MPa; 4) The EPP raw material used is high-temperature resistant EPP, i.e., binary copolymer high melt deterministic polypropylene with a melting point of 142-150℃, and the EPP products are prepared using a supercritical carbon dioxide autoclave foaming process. These requirements ensure that the EPP product surface has no obvious defects, facilitating the yield control of the subsequent lamination process.

[0032] The EPP product surface treatment equipment provided by the present invention introduces an adsorption bonding system 2, which uses adsorption to coat the EPP product with a membrane material 5. The membrane material 5 adapts to the outer contour of the EPP product under the adsorption effect, so as to achieve complete bonding of the EPP product without bubbles or gaps. The bonding effect is not affected by the shape of the EPP product, and it can achieve coating of irregularly shaped EPP products.

[0033] To facilitate coating, the membrane material 5 is preferably a multi-layer composite structure. In this invention, the membrane material 5 can be manufactured by other composite processes such as multi-layer blow molding, multi-layer co-extrusion, and coating, which are not limited here. Specifically, the membrane material 5 preferably includes an adhesive layer and at least one functional layer composited on top of the adhesive layer. The adhesive layer is located at the bottom layer and directly contacts the surface of the EPP product. Under heat, the adhesive layer melts and forms a firm bond with the EPP substrate. The functional layer imparts the desired appearance or physicochemical properties to the EPP product, such as high gloss, wear resistance, UV resistance, and scratch resistance.

[0034] Furthermore, the EVA adhesive layer in this invention can be determined based on the processing temperature of the actual functional layer and the operating temperature of the final product; preferably, the melting point range of the adhesive layer is 45-130℃, so as to match the thermal properties of the EPP material and ensure good melt flow without damaging the substrate at a lower temperature. This temperature range can be controlled by selecting suitable copolymer materials (such as ethylene-vinyl acetate copolymer EVA, polyolefin elastomer POE, etc.).

[0035] The material of the functional layer is determined according to the functional requirements of the EPP product. The functional layer can be selected from one or more of the following composites: a printing layer, a wear-resistant layer, or a hardening layer, depending on the actual needs. Specifically, the material of the functional layer is preferably selected from at least one of PMMA, PET, PP, and PE. These materials each have their own advantages: PMMA has high transparency and hardness, making it suitable for high-gloss finishes; PET has excellent dimensional stability and mechanical strength; and PP and PE are compatible with EPP substrates and are easy to recycle.

[0036] Furthermore, the thickness of the adhesive layer in this invention is preferably in the range of 0.25-0.55mm, specifically set to be 0.05mm greater than the depth of the texture on the surface of the EPP product. This thickness range ensures sufficient melt filling capacity to fill the micropores on the EPP surface, while avoiding excessive thickness that could lead to cooling deformation or increased costs. The thickness of the functional layer is in the range of 0.1-1.0mm, which can be flexibly adjusted according to the usage requirements of the final product, taking into account both aesthetics and practicality.

[0037] To ensure the coating effect, the present invention preferably includes a hot air system 21, a pressing system 22 and an adsorption system 23 arranged from top to bottom; during operation, the membrane material 5 is located between the pressing system 22 and the adsorption system 23.

[0038] The hot air system 21 is used to preheat and soften the film material 5, giving it good extensibility and bonding fluidity. The hot air system 21 is a temperature-controlled hot air system, which preferably reaches the required bonding temperature of the film material 5 within 2 seconds and is evenly distributed on the surface of the EPP product to be bonded. The temperature difference between each area should be controlled within ±1.5℃. The bonding temperature T is set according to the melting temperature T1 of the EVA adhesive layer and the heat distortion temperature T2 of the functional layer. In principle, T=T1=T2, but the maximum deviation between them should not exceed 6℃.

[0039] The pressing system 22 applies vertical pressure to make the softened film material adhere tightly to the surface of the EPP product. The pressing system 22 is mainly designed to ensure that the film material 5 and the bottom mold surface or operating table surface form a sealed space during the mold closing process, in preparation for vacuum adsorption. The upper part of the pressing system 22 is made of elastic rubber material around its perimeter to ensure that the film material 5 will not be stuck to the operating table without high temperature, and that a sealed space can be formed.

[0040] The EPP product surface treatment equipment provided by the present invention also includes a hydraulic station system. The hydraulic station system mainly controls the up and down movement of the pressing system 22. Its operating height H1 depends on the surface height H2 of the EPP product that needs to be treated. In principle, H1≥H2.

[0041] The adsorption system 23 uses negative pressure suction to ensure that the membrane material 5 and the EPP product are completely bonded without bubbles or gaps, which is especially suitable for EPP products with complex curved surface structures.

[0042] The preferred adsorption system 23 of the present invention includes an adsorption chamber 231 and a mold 232 installed on the adsorption chamber 231; and the adsorption chamber 231 is connected to a vacuum system.

[0043] Specifically, the adsorption chamber 231 is connected to a vacuum system via a pipe, enabling the rapid establishment of a negative pressure environment within a sealed space. The mold 232 is used to fix a molding die that matches the shape of the EPP product to be treated. The surface of the mold is provided with vent holes, allowing the vacuum adsorption force to be evenly transmitted to the back of the membrane material, guiding it to precisely conform to the contour of the EPP product.

[0044] The vacuum system requires a variable frequency vacuum high-pressure blower. The preferred blower pressure is 80mbar~1000mbar and the air volume is 150 cubic meters / hour~2000 cubic meters / hour, depending on the size of the equipment.

[0045] Specifically, mold 232 is mainly installed and fixed by screws on four sides with a screw spacing of 20 cm. The mold material is cast aluminum or silicone. The mold structure contacts the area of ​​the EPP product surface that does not need to be treated, and plays a supporting role in the EPP product during the membrane adsorption process. At the same time, continuous intermittent through holes with a length of not less than 10 mm and a width of not less than 3 mm need to be cut between the mold fixing screws, mainly for adsorption and degassing.

[0046] In this invention, a sealing strip 233 is preferably provided between the mold 232 and the adsorption chamber 231. The sealing strip 233 is arranged around the contact interface between the two to effectively prevent vacuum leakage, ensure the negative pressure stability in the adsorption chamber, and thus improve the bonding accuracy and yield.

[0047] Furthermore, the preferred EPP product surface treatment equipment of the present invention also includes a cutting system 3 located between the adsorption bonding system 2 and the material collection and traction device 4, which is used to precisely cut the excess film material 5 after bonding is completed, so as to realize the product segmentation or partial trimming.

[0048] Specifically, the preferred cutting system 3 of this invention includes a die 31 and a press 32 disposed above the die 31. The press 32 moves downwards, working in conjunction with the die 31 below to complete the punching action. The die 31 can be customized according to the product size and shape, enabling simultaneous cutting of multiple points or multiple areas in one operation, improving processing efficiency and consistency.

[0049] During the operation of this EPP product surface treatment equipment, the roll-shaped film 5 is first introduced into the equipment by the feeding traction device 1 and the receiving traction device 4, and then smoothly conveyed into the adsorption bonding system 2 via guide rollers. Simultaneously, the pre-formed EPP product is placed on the mold 232 within the adsorption system 23. Subsequently, the hot air system 21 is activated to uniformly heat the film 5 passing below, ensuring the functional layer remains rigid while the adhesive layer softens or melts. Next, the film 5 descends between the pressing system 22 and the adsorption system 23. At this point, the vacuum system begins operation, creating a negative pressure inside the adsorption chamber 231. Through the vents on the mold surface, the film 5 is strongly adsorbed and tightly adhered to the surface of the EPP product. Simultaneously with vacuum adsorption, the pressing system 22 applies a certain pressure, promoting molecular diffusion and interfacial fusion between the adhesive layer and the EPP substrate, achieving high-quality bonding. After lamination, the membrane material 5 carries the laminated EPP product forward under traction and enters the cutting system 3. The press 32, together with the die 31, performs precise cutting to remove excess material or divide it into individual products, which are then output to the next process or collection area.

[0050] The present invention enables continuous and automated operation of the entire surface treatment process for EPP products, and is applicable to EPP products of different sizes and shapes, significantly improving production efficiency and product consistency.

[0051] In existing technologies, some EPP products utilize techniques such as in-mold molding and hot-stamping mirror finishes. However, these only address surface smoothness or impermeability, failing to provide comprehensive surface enhancement for all EPP products. The EPP product surface treatment equipment provided by this invention utilizes the softening effect of hot air system 21, the vacuum adsorption effect of adsorption system 23, and the mechanical pressing effect of pressing system 22 to achieve composite bonding of the membrane material 5. This effectively eliminates bubbles, wrinkles, and edge warping, making it suitable for EPP products with different geometric shapes and complex curved surface structures. Therefore, it can address all surface function enhancements within the EPP product industry through a single technology. Furthermore, this equipment can adapt to various specifications of EPP products and different types of membrane materials 5 by changing molds and adjusting process parameters (such as temperature, pressure, and speed), thereby improving the surface of EPP products in terms of wear resistance, scratch resistance, printability, impermeability, and aesthetics.

[0052] The EPP product surface treatment equipment provided by this invention addresses the shortcomings of in-mold molding lamination. In-mold molding lamination has higher requirements for the film material, requiring it to have strong extensibility and flexibility, making it difficult to enhance the surface hardness and plastic-grade wear resistance of EPP products. Secondly, in-mold molding lamination cannot achieve the desired display of colorful graphics and text under the high temperature conditions inside the mold. Compared with mirror molding, mirror molding has weaker plasticity, only displaying a plasticized PP surface, and also requires subsequent processing, making the operation cumbersome and the yield rate low (the wall thickness of the internal cells of EPP is not necessarily uniform, and burn-through may occur during the heat plasticization process).

[0053] In summary, this invention provides an EPP product surface treatment equipment that can achieve uniform heating, vacuum adsorption and pressing bonding between the film material and the EPP product, and integrates functional modules such as traction conveying, hot air softening, vacuum adsorption molding, pressing and shaping and online cutting to form an integrated production line.

[0054] To facilitate understanding, this invention will be further illustrated using the example of improving the surface hardness of EPP sheet products: The desktops of study desks are mostly made of particleboard or plywood as the core material, with wood veneer or other textured surfaces laminated on the surface. During transportation, the desktops are heavy, resulting in high transportation costs and a high breakage rate. Furthermore, it is difficult to avoid formaldehyde or odor issues within the boards. If EPP boards are used as an alternative core material, and the EPP product surface treatment equipment described in this invention is used to improve the aesthetics, wear resistance, and surface hardness, the drawbacks of the original solution can be solved simultaneously.

[0055] Specifically, this invention uses milky white 10P high-rigidity EPP material. The core layer can meet the mechanical performance requirements of the study desk desktop in terms of bending, compression and other aspects during actual use. The EPP molding mold uses 0.3mm pinhole air plugs arranged at 10mm intervals. The texturing uses dot-shaped protrusions with a texturing depth of 0.35mm. The mold material is aluminum alloy. The final EPP product surface has no obvious pinholes or pit defects.

[0056] The top surface and sides of EPP sheet products require enhanced surface abrasion resistance and hardness, while also possessing a white matte finish. The custom composite film consists of three layers. The first layer is a 0.4mm thick EVA adhesive layer, using EVA with a melting temperature of 80℃; the second layer is a 0.15mm thick PET printing layer, with a vacuum forming softening temperature of 85℃ and a milky white color; the third layer is a 0.1mm thick PMMA film material containing alumina nanoparticles, with a frosted matte finish.

[0057] Using the EPP product surface treatment equipment provided by this invention, the hot air temperature is adjusted to 86℃ and the vacuum degree is adjusted to 0.06Mpa for bonding production. The resulting EPP study desk desktop has good wear resistance, is environmentally friendly (formaldehyde-free and odorless), and is 80% lighter than before.

[0058] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A surface treatment method for EPP products, characterized in that, Includes the following steps: S1: Place the membrane material (5) on top of the EPP product; S2: The membrane material (5) is bonded to the surface of the EPP product through an adsorption bonding process to achieve surface treatment of the EPP product.

2. The surface treatment method for EPP products as described in claim 1, characterized in that, The process of attaching the membrane material (5) to the surface of the EPP product by adsorption bonding includes: preheating and softening the membrane material (5), pressing the membrane material (5) onto the surface of the EPP product, and using negative pressure suction to attach the membrane material (5) to the surface of the EPP product.

3. The surface treatment method for EPP products as described in claim 1, characterized in that, The membrane material (5) includes an adhesive layer and at least one functional layer composited on top of the adhesive layer.

4. The surface treatment method for EPP products as described in claim 3, characterized in that, The melting point of the adhesive layer is in the range of 45-130℃.

5. A surface treatment device for EPP products, characterized in that, The surface of an EPP product is treated by the surface treatment method for EPP products as described in any one of claims 1-4; the surface treatment equipment for EPP products includes a feeding traction device (1), an adsorption bonding system (2), and a receiving traction device (4) arranged sequentially adjacent to each other; the receiving traction device (4) and the feeding traction device (1) drive the film material (5) through the adsorption bonding system (2).

6. The EPP product surface treatment equipment as described in claim 5, characterized in that, The adsorption bonding system (2) includes a hot air system (21), a pressing system (22) and an adsorption system (23) arranged sequentially from top to bottom; the membrane material (5) is located between the pressing system (22) and the adsorption system (23).

7. The EPP product surface treatment equipment as described in claim 6, characterized in that, The adsorption system (23) includes an adsorption chamber (231) and a mold (232) installed on the adsorption chamber (231); the adsorption chamber (231) is connected to a vacuum system.

8. The EPP product surface treatment equipment as described in claim 7, characterized in that, A sealing strip (233) is provided between the mold (232) and the adsorption chamber (231).

9. The surface treatment equipment for EPP products as described in any one of claims 5-8, characterized in that, It also includes a cutting system (3) located between the adsorption bonding system (2) and the material collection and traction device (4).

10. The EPP product surface treatment equipment as described in claim 9, characterized in that, The cutting system (3) includes a die (31) and a press (32) disposed above the die (31).

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