Core material carving process for PHC mold pressing leather with leather patterns

Abstract

The invention discloses a core material carving process of PHC mould pressing leather. The core material carving process comprises the following steps: S1, pretreatment and activation of a base material: a, selecting PHC leather as a surface layer material; b, cleaning and preheating the surface of the core material; s2, pre-carving, wherein rough machining is conducted on lines of the preheated core material; s3, hot-pressing compounding: a, placing the core material in a lower die cavity of a die, and covering the rough carving texture surface of the core material with the leather; b, closing the mold; s4, fine carving: carrying out micro-carving on the non-composite surface of the core material by adopting a heat conduction carving tool; and S5, cooling and shaping: carrying out gradient cooling. Through the synergistic effect of the pre-carving process and the fine carving process, the pre-carving process forms a preliminary contour matched with the target texture on the surface of the core material, the fine carving process further refines the texture structure, the texture adaptation degree of the leather and the core material is remarkably improved, the texture adaptation degree of the leather and the core material reaches 88%-92%, and the texture matching degree of the leather and the core material reaches 98%-92%. The problems of texture dislocation, incoordination and the like in a traditional process are solved.

Description

Technical Field

[0001] This invention relates to the field of texture engraving technology, and in particular to a core material engraving process for PHC molded leather. Background Technology

[0002] PHC molded leather is a type of leather that uses a molding process to press specific, complex leather patterns onto the surface, creating a texture and feel similar to natural leather. In leather product manufacturing, PHC molded leather is typically used as the surface layer, with a core material used as the base fabric for lamination, combining the appearance and texture of leather with the strength and support of the core material.

[0003] Currently, traditional core material engraving techniques often employ fixed patterns or textures, making it difficult to match the complex patterns of PHC molded leather. This results in visual and tactile inconsistencies in the final product, affecting its overall quality and aesthetics. Furthermore, the core material is prone to dimensional deviations and edge burrs during the lamination process, failing to meet the high compatibility requirements between the core material and the leather's texture. Therefore, a new core material engraving technique for PHC molded leather has been invented to address these shortcomings in compatibility and coordination between the core material and the leather. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a core material engraving process for PHC molded leather.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] S1. Substrate pretreatment and activation:

[0007] a. Select PHC textured leather that has completed the molding process as the surface material;

[0008] b. Select core material, clean the surface of the core material and preheat it;

[0009] S2. Pre-carving: Roughly process the texture of the preheated core material, and then cool it to 35-45℃ after rough carving.

[0010] S3, Hot-pressed composite:

[0011] a. Place the pre-carved and cooled core material into the lower mold cavity of the mold, and cover the rough-carved textured surface of the core material with leather texture. Apply adhesive evenly to the rough-carved surface of the core material and the bonding surface of the leather texture.

[0012] b. Close the mold and apply temperature and pressure to make the textured leather fit tightly to the rough outline of the core material;

[0013] S4. Fine carving: The non-composite surface of the core material is micro-carved using a heat conduction carving tool, and the instantaneous heat energy penetrates the core material and is conducted to the bonding interface;

[0014] S5. Cooling and Shaping: Gradual cooling is applied to the material.

[0015] In step S1, the selected core material is ultrasonically cleaned and then preheated in a constant temperature environment of 50-60℃ for 30 minutes, with the humidity of the preheating environment controlled below 30%RH.

[0016] In step S3, the adhesive is a polyurethane (PU) adhesive, and 5% to 8% nano-silica is added to the polyurethane adhesive.

[0017] In step S3, the temperature is 140–160°C, the pressure is 15–25 MPa, and the pressure holding time is 5–8 min.

[0018] In step S4, the heat conduction engraving tool is a galvanometer scanning laser head with a focused spot diameter of 0.1 to 0.3 mm, a scanning speed of 500 to 800 mm / s, and a heat penetration depth of 1.2 to 1.5 times the core material thickness.

[0019] In step S5, the shaping and cooling process adopts a three-stage temperature control: the first stage is air cooling to 80-100°C, the second stage is water mist cooling to 40-50°C, and the third stage is room temperature standing for more than 30 minutes.

[0020] The water mist cooling uses pure water.

[0021] The process also includes a post-processing step, which involves infrared trimming of the edges of the composite material. The infrared wavelength is 980 nm and the temperature is 120–150 °C.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] Through the synergistic effect of pre-carving and fine carving processes, the pre-carving process forms an initial outline on the core material surface that matches the target texture, while the fine carving process further refines the texture structure, significantly improving the texture compatibility between the leather and the core material. This results in a texture compatibility of 88%–92%, solving problems such as texture misalignment and inconsistency in traditional processes, thus achieving a seamless connection between the leather and the core material. The dual-stage carving process ensures a tight bond between the core material and the leather, increasing the bonding strength by approximately 2.5 times. Under this dual-stage carving system, the matching texture depth and high bonding strength form a synergistic support structure, increasing the product's abrasion resistance and significantly improving wear resistance, thereby extending the product's lifespan. Detailed Implementation

[0024] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0025] This embodiment discloses a core material engraving process for PHC molded leather, including the following steps:

[0026] S1. Substrate pretreatment and activation:

[0027] a. Select PHC textured leather that has completed the molding process as the surface material. After molding, PHC textured leather has clear texture and stable texture. As a surface material, it can provide a good appearance and tactile foundation for composite materials, and can better predict and control its deformation behavior in subsequent hot pressing composite, thereby improving the matching degree between the textured leather and the core material.

[0028] b. Select the core material and perform ultrasonic cleaning on its surface to thoroughly remove contaminants such as grease, dust, and release agents, ensuring a clean bonding surface and creating favorable conditions for subsequent adhesive bonding. Then, preheat it in a constant temperature environment of 50-60℃ for 30 minutes. This temperature activates the core material surface while remaining far below its softening point or heat distortion temperature, thus preventing deformation caused by preheating. Preheating for 30 minutes ensures that the internal temperature of the core material reaches the set value uniformly. In addition, the humidity of the preheating environment is controlled below 30%RH to prevent moisture from condensing or seeping into the core material surface during preheating or subsequent processes. Therefore, cleaning and preheating the core material not only enhances its surface activity, improving compatibility and bonding strength with the adhesive, but also helps reduce deformation caused by temperature differences during subsequent processing, improving dimensional stability. Simultaneously, the low-humidity environment prevents the core material from absorbing moisture, avoiding any impact on the subsequent lamination effect.

[0029] S2. Pre-carving: The preheated core material undergoes rough texturing to create a general texture outline on its surface, followed by controlled cooling to 35-45℃. Rough carving provides a preliminary texture foundation for subsequent composite leather adhesion, increasing the bonding area and thus improving the tightness of the bond.

[0030] The cooling and temperature control stage is crucial. Excessive temperature can affect the uniformity and flowability of the adhesive coating, potentially causing deformation or damage to the leather during hot-pressing. Conversely, insufficient temperature may result in inadequate adhesive activity, preventing a sufficient bonding reaction between the adhesive and the core material and leather. Therefore, a temperature range of 35–45°C ensures relative stability of the core material's internal structure while providing a suitable temperature environment for subsequent adhesive application and lamination processes, thus guaranteeing process continuity and quality stability.

[0031] S3, Hot-pressed composite:

[0032] a. Place the pre-carved and cooled core material into the lower mold cavity of the mold, and cover the rough-carved textured surface of the core material with leather. Apply polyurethane (PU) adhesive evenly to the rough-carved surface of the core material and the leather bonding surface, and add 5% to 8% nano silica to the adhesive. Applying adhesive to both the rough-carved surface of the core material and the leather bonding surface can ensure the maximum contact area and the uniformity of the adhesive layer, so that the complex textured surface is fully wetted.

[0033] Polyurethane (PU) adhesives possess excellent bonding properties, flexibility, and durability, enabling them to adapt to the different material characteristics of leather and core materials, achieving a strong bond between the two and maintaining the stability and impact resistance of the composite material during use. Adding 5%–8% nano-silica significantly improves the mechanical properties, abrasion resistance, and heat resistance of the adhesive. The particle structure of nano-silica fills the tiny voids within the adhesive, enhancing intermolecular cross-linking and increasing the density of the adhesive layer. This results in a stronger and more durable bond at the bonding interface of the composite material, effectively extending its service life and enhancing its suitability for complex environments.

[0034] In addition, the addition of 5% to 8% nano silica is a balance point. If the addition is too little, the effect will be not obvious. If the addition is too much, it will cause the viscosity of the adhesive to increase dramatically, making it difficult to disperse and affecting the wettability, and even causing agglomeration.

[0035] b. After closing the mold, apply a temperature of 140-160℃ and a pressure of 15-25MPa, and hold the pressure for 5-8 minutes to allow the polyurethane (PU) adhesive to melt, flow, and fully impregnate the core material and leather surface, thereby making the leather texture closely fit the rough outline of the core material.

[0036] The temperature range of 140–160℃ ensures that the polyurethane (PU) adhesive is fully melted, activated, and cured rapidly. Temperatures below this range will result in incomplete curing and insufficient bond strength; while excessively high temperatures may cause the leather to scorch, discolor, or the core material to soften and deform excessively. High pressure of 15–25 MPa can stretch and deform the leather, ensuring full contact between the leather and the core material at the microscopic level. Insufficient pressure will lead to poor adhesion and unclear texture.

[0037] Holding the pressure for 5 to 8 minutes ensures that the adhesive has sufficient time to complete the curing reaction, forming a stable bonding structure. This gives the composite material high-strength bonding performance, enabling it to withstand external mechanical stress and ensuring that the leather texture does not peel off or curl during subsequent processing and use.

[0038] S4. Fine carving: Using heat conduction carving tools to micro-carve the non-composite surface of the core material, instantaneous heat energy penetrates the core material and is conducted to the bonding interface, causing the PU adhesive layer at the interface to soften or slightly melt instantly, releasing the localized micro-internal stress generated during the composite cooling process, especially in areas with drastic texture changes.

[0039] Specifically, a galvanometer scanning laser head is used as a heat conduction engraving tool, with a focused spot diameter of 0.1–0.3 mm and a scanning speed of 500–800 mm / s. The thermal penetration depth is 1.2–1.5 times the core material thickness. This allows for micro-engraving of the non-composite surface of the core material. This means that the energy of the galvanometer scanning laser head is sufficient to penetrate the entire core material thickness and act on the cross-sectional area without excessively ablating the non-composite surface. If the depth is insufficient, the effect will not reach the interface; if the depth is too deep, it may damage the leather texture.

[0040] The galvanometer scanning laser head boasts high-precision and high-efficiency engraving capabilities. Its small and precisely controllable focused spot allows for rapid engraving of delicate and complex textures on the core material surface, accurately matching the texture details of leather. This results in a more realistic and natural surface texture in the composite material, enhancing both visual and tactile effects. Proper control of heat penetration depth ensures effective instantaneous heat transfer to the bonding interface, causing microscopic adjustments to the core material's internal structure and further strengthening the bond with the leather, while preventing excessive heat from damaging the leather. This precision engraving process not only perfects the surface texture of the composite material but also optimizes internal bonding quality through heat transfer, giving the composite material higher processing precision and quality.

[0041] S5. Cooling and Shaping: Gradient cooling can avoid thermal stress caused by rapid cooling of composite materials from high temperature, which can lead to delamination, warping and deformation. Furthermore, gradient cooling makes the shrinkage inside and outside the material more synchronized, thus allowing the stress to be released gradually.

[0042] The cooling and setting process employs a three-stage temperature control: the first stage involves air cooling to 80–100°C, the second stage involves water mist cooling to 40–50°C, and the third stage involves standing at room temperature for at least 30 minutes. This staged cooling avoids thermal stress concentration within the composite material due to sudden cooling, which can lead to cracking, deformation, and other defects. Air cooling to 80–100°C rapidly reduces heat on the material's surface and some of its internal structure, allowing the adhesive to initially cure while maintaining the relative stability of the overall material structure.

[0043] Water mist cooling to 40-50°C can further and evenly reduce the internal temperature of the material, allowing the adhesive to fully cure and ensuring a stable chemical and physical bond between the leather texture and the core material, thus enhancing the dimensional accuracy and hardness of the material. Furthermore, water mist cooling uses pure water, avoiding contamination from impurities or the formation of water stains.

[0044] Finally, allowing the composite material to stand at room temperature allows the internal stress to be fully released, stabilizing the overall performance and ensuring the product's reliable quality during subsequent storage, transportation, and use.

[0045] S6. Post-processing: The edges of the composite material are trimmed using infrared radiation at a wavelength of 980nm and a temperature of 120–150℃. Infrared trimming utilizes a specific wavelength of infrared light to precisely heat the edge area, softening the adhesive and material at the edge. The 980nm wavelength may have good absorption for leather and core materials, achieving efficient heating, while the 120–150℃ temperature is sufficient to soften the polyurethane (PU) adhesive layer and part of the core material, making cutting smoother and improving edge neatness, sealing, and durability.

[0046] Infrared trimming effectively solves problems such as burrs and curling at the edges of composite materials, ensuring neat, smooth edges and a refined, aesthetically pleasing appearance. Furthermore, the infrared trimming process has a small impact area on the material, without damaging the internal bonding structure and overall performance of the composite material, making it an efficient and environmentally friendly post-processing method.

[0047] Comparative example:

[0048] This comparative example discloses the texture forming process of PHC molded leather and core material, including the following steps:

[0049] S1. Substrate pretreatment and activation:

[0050] a. Select PHC textured leather that has completed the molding process as the surface material;

[0051] b. Select the core material, perform ultrasonic cleaning on the surface of the core material, and then preheat it in a constant temperature environment of 50-60℃ for 30 minutes. The humidity of the preheating environment should be below 30%RH.

[0052] S2, Hot-pressed composite:

[0053] a. Place the preheated but uncarved core material in the lower mold cavity of the mold, cover the smooth surface of the core material with leather texture, and evenly coat the smooth surface of the core material and the leather texture bonding surface with polyurethane (PU) adhesive containing 5% to 8% nano silica.

[0054] b. Close the mold, apply a temperature of 140-160℃ and a pressure of 15-25MPa to make the leather texture closely fit the plane contour of the core material, and hold the pressure for 5-8 minutes;

[0055] S3, Cooling and Shaping: The first stage is air cooling to 80-100℃, the second stage is water mist cooling to 40-50℃, and the third stage is standing at room temperature for more than 30 minutes.

[0056] S4. Post-processing: The edges of the composite material are trimmed with infrared light at a wavelength of 980 nm and a temperature of 120–150 °C.

[0057] This invention discloses the effects of two different processes on the engraving of textured leather and core material. In the comparative example, a mold is used to press the textured leather and the core material placed on the textured leather. Although the surface of the textured leather that is in direct contact with the mold can form a relatively clear texture, the texture of the surface of the core material placed on it is blurry or even completely missing. This results in the inability to effectively fit the textured leather and the planar structure of the core material. Furthermore, relying solely on adhesives for bonding can easily lead to quality problems such as local detachment or the formation of air bubbles.

[0058] The embodiments of this invention effectively solve the aforementioned problems by employing an innovative process of pre-carving and fine-carving the core material. In the process, the core material is first pre-carved to remove surface imperfections and initially form a texture outline. Then, a fine-carving process is performed to further optimize the texture details, ensuring it matches the texture of the molded leather. When the mold presses the leather, due to the thinner leather, the molded texture is clearer and sharper, and it closely adheres to the pre-carved and fine-carved core material texture, forming a nested structure. This structure, combined with the adhesive effect of the adhesive, greatly enhances the bonding force between the leather and the core material, making the bond tighter and stronger, effectively avoiding localized separation and air bubbles, thereby significantly improving the overall quality and performance of the product.

[0059] The present invention measures the texture compatibility, adhesion, surface smoothness and durability of the leather and core material composite products prepared in the examples and comparative examples. The measurement methods and results are as follows.

[0060] I. Measurement Method:

[0061] 1. Texture compatibility:

[0062] The surface texture of the leather and the engraved texture of the core material were scanned and collected using an optical texture analyzer. The shape, direction, density and other features of the texture were compared and analyzed by image processing algorithms to obtain the percentage value of texture fit.

[0063] 2. Adhesion:

[0064] One end of the sample is fixed to the upper clamp of the tensile testing machine, and the other end is fixed to the lower clamp. The sample is pulled apart at a certain speed, and the force value during the stretching process is recorded to calculate the adhesion force.

[0065] 3. Surface flatness:

[0066] A flatness measuring instrument is used. The measuring head of the instrument is gently placed on the sample surface, and each measuring point is recorded. The average value is calculated to obtain the overall surface flatness.

[0067] 4. Durability:

[0068] A friction testing machine was used, and a suitable friction head was selected to rub the sample surface back and forth. The number of times obvious damage such as friction, discoloration, and fiber exposure appeared on the material surface was observed.

[0069] II. Measurement Results

[0070] Table 1 Performance test results of the composite product of leather texture and core material

[0071] Texture fit (%) Adhesion (MPa) Surface flatness (mm) Friction resistance (thousands of cycles) Example 88～92 3.2～3.8 0.2～0.3 8～10 Comparative Example 50～55 1.2～1.5 0.8～1.2 3～4

[0072] To evaluate the matching degree between the texture of the leather and the core material, this invention measures the texture fit (the degree of conformity of the texture in terms of position, direction, and depth) of the embodiments and comparative examples. According to Table 1, the texture fit of the embodiments of this invention is 88%–92%, while the texture fit of the comparative examples is only 50%–55%. This indicates that the texture fit between the leather and the core material in the embodiments is higher, and the leather can fit the engraved texture of the core material very well. The textures of the two are coordinated with each other. This is because the embodiments employ pre-carving and fine carving processes. Pre-carving pre-forms a basic texture outline on the core material corresponding to the target leather texture height; fine carving then refines this outline to ensure that the depth and shape of the texture details perfectly match the subsequently applied leather.

[0073] Compared to the example, the comparative example directly forms the texture through molding the leather. The leather cannot perfectly fit the core material surface, and the textures of the two are misaligned and inconsistent, resulting in a significant reduction in the actual contact area between the leather and the core material. The effective bonding interface is damaged, thereby weakening the adhesion between the leather and the core material. This shows that the pre-carving and fine carving processes play a key role in improving the texture matching degree.

[0074] Adhesion is a crucial indicator of the strength of the bond between the leather and the core material. Good adhesion ensures that the product is less prone to cracking, peeling, or other quality issues during use. The adhesion in this embodiment of the invention reaches 3.2 MPa to 3.8 MPa, indicating a tight bond between the leather and the core material. It is not easily separated under external force. This is attributed to the pre-carving process that creates an initial texture outline on the core material surface. Subsequent hot-pressing and fine carving further optimize this process, significantly increasing the effective contact area and micro-interlocking depth between the leather and the core material. This substantially enhances the bonding strength between the leather and the core material and reduces the formation of air bubbles.

[0075] The adhesion of the comparative sample was only 1.2MPa to 1.5MPa. This may be due to the lack of pre-carving and fine carving processes, which limited the contact area between the core material and the leather texture. The adhesive could not fully penetrate into the leather texture and the core material for effective bonding, resulting in low adhesion. Furthermore, the leather texture could not completely and evenly adhere to the surface of the core material, affecting the final surface smoothness and overall texture of the product.

[0076] Surface flatness is used to evaluate the smoothness and uniformity of a product's surface. In this embodiment of the invention, the surface flatness is between 0.2mm and 0.3mm, indicating that after pre-carving and fine carving processes, the core material and the leather texture can be tightly bonded, with virtually no obvious protrusions or depressions on the surface, resulting in an overall smooth and flat surface that meets the product's appearance quality requirements. This also demonstrates the optimization effect of pretreatment, hot-pressing, and other steps on the material's surface morphology.

[0077] The surface flatness of the comparative example was 0.8mm to 1.2mm, which was significantly worse than that of the example. This indicates that without pre-carving, the core material surface would lack a reference texture to guide the precise bonding of the leather texture. Without fine carving, defects generated during the bonding process cannot be eliminated, making it difficult to form a tight and uniform interface bond between the leather texture and the core material. It is very easy for air bubbles to be trapped or for local stress concentration to form bulges during the hot-pressing process. This uneven surface state is very likely to become the starting point for wear or damage when subjected to friction, thus negatively affecting the friction resistance of the product.

[0078] Compared with the comparative example, the friction resistance of the embodiment of the present invention is significantly higher than that of the comparative example, indicating that the product prepared by the embodiment has better wear resistance and can withstand more friction cycles without significant damage. This is related to the good bonding between the core material and the leather texture and the overall stability of the material. The pre-carving and fine carving processes enable the two to support each other and work synergistically, thereby improving durability.

[0079] The abrasion resistance test is used to evaluate the product surface's ability to resist wear and maintain its appearance integrity during actual use, directly reflecting the product's durability and quality stability. The abrasion resistance test of the embodiments of this invention is significantly higher than that of the comparative examples. This indicates that the products of the embodiments can withstand more abrasion cycles without damage to the leather texture or separation from the core material. This is attributed to the embodiments' use of a combined pre-carving and fine-carving process, which ensures a tight bond between the leather texture and the core material, effectively resisting shear forces during friction. In contrast, the comparative examples, lacking pre-carving and fine-carving, exhibit obvious bubbles, wrinkles, or bulges on their surfaces. These protrusions and weak areas will wear and crack during friction.

[0080] In summary, the embodiments, through pre-carving and fine carving processes, enable the core material and leather to outperform the comparative example in key indicators such as texture compatibility, adhesion, surface smoothness, and abrasion resistance. The overall product quality is higher, the performance is more stable, and it can better meet the actual use needs, thus fully demonstrating the important role of pre-carving and fine carving steps in improving the compatibility between the core material and leather.

[0081] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the invention.

Claims

1. A process for engraving a core material of a PHC moulded leather with a pattern, characterized in that, It comprises the following steps: S1, substrate pretreatment and activation: a. Selecting PHC embossed leather which has completed the molding process as the surface material; b. Selecting core material, cleaning the surface of the core material and performing preheating treatment; S2, pre-engraving: rough machining the engraved lines on the preheated core material, and controlling the temperature to cool to 35-45℃ after rough engraving; S3, hot pressing composite: a. Placing the core material which has completed pre-engraving and has been cooled and shaped in the lower mold cavity of the mold, and covering the embossed leather on the rough engraved texture surface of the core material, uniformly coating adhesive on the rough engraved surface of the core material and the adhesive surface of the embossed leather; b. Closing the mold, applying temperature and pressure to make the embossed leather closely fit the rough engraved profile of the core material; S4, fine engraving: using a heat conduction engraving tool to micro-engrave the non-composite surface of the core material, and the instantaneous heat energy penetrates the core material and is conducted to the adhesive interface; S5, cooling and shaping: gradient cooling is performed.

2. A process for engraving a core material for PHC molded embossed leather as claimed in claim 1, wherein, In step S1, the selected core material is placed in a constant temperature environment of 50-60℃ after ultrasonic cleaning for preheating for 30min, and the preheating environment humidity is controlled below 30%RH.

3. A process for engraving a core material for PHC molded embossed leather as claimed in claim 1, wherein, In step S3, the adhesive is polyurethane (PU) adhesive, and 5%-8% nanometer silicon dioxide is added to the polyurethane adhesive.

4. A process for engraving a core material for PHC molded embossed leather as claimed in claim 1, wherein, In step S3, the temperature is 140-160℃, the pressure is 15-25MPa, and the pressure holding time is 5-8min.

5. A process for engraving a core material for PHC molded embossed leather as claimed in claim 1 wherein, In step S4, the heat conduction engraving tool is a galvanometer scanning laser head, the focused spot diameter is 0.1-0.3mm, the scanning speed is 500-800mm / s, and the heat penetration depth is 1.2-1.5 times the thickness of the core material.

6. A process for engraving a core material for PHC molded embossed leather as claimed in claim 1, wherein, In step S5, the shaping and cooling adopts three-stage temperature control, the first stage is air cooling to 80-100℃, the second stage is water mist cooling to 40-50℃, and the third stage is room temperature standing for more than 30min.

7. A process for engraving a core material for PHC molded embossed leather as claimed in claim 6, wherein, The water mist cooling uses pure water.

8. Use of a PHC die embossed leather core material engraving process according to claim 1, characterized in that, It also includes a post-treatment process, which performs infrared trimming on the edges of the composite material, the infrared wavelength is 980nm, and the temperature is 120-150℃.