Formulation and preparation method of three-layer co-extruded sound-absorbing magic hook

Abstract

This invention relates to the field of magic hook technology and discloses a formula and preparation method for a three-layer co-extruded sound-absorbing magic hook. The preparation method includes the following steps: raw material preparation, three-layer co-extrusion molding, molding and cooling, and low-temperature multiple light pressing for shaping. By adopting a three-layer co-extrusion structure design, the bottom layer, middle layer, and top layer achieve differentiated functional allocation: the bottom layer does not add slip agent to ensure good adhesion between it and the adhesive layer, avoiding slippage during winding and slitting; the middle layer adds slip agent and uses PP resin as the main load-bearing skeleton to ensure the rigidity and uprightness of the column and prevent the mushroom head from bending and deforming; the top layer adds functional elastomer and slip agent to give the mushroom head a soft and smooth characteristic, reducing frictional noise when detaching, achieving a sound-absorbing effect while taking into account the overall mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of magic hook technology, specifically to the formulation and preparation method of a three-layer co-extruded sound-absorbing magic hook. Background Technology

[0002] As people's living standards improve, their pursuit of material goods also increases. Hook and loop fasteners are simple in structure, low in cost, and easy to use, therefore they are widely used in clothing, shoes, gloves, bags, vehicles, cushions, electronic wires, chargers, display items, etc. The hook and loop are part of the hook and loop fastener, usually used in conjunction with the loop side of the fastener. The hook and loop are used to hook and connect the loop sides of the fastener to achieve the purpose of connection.

[0003] Currently, traditional magic hooks typically employ a single-layer structure or a simple two-layer co-extrusion process during production, resulting in the inability to achieve differentiated functional designs for their bottom, middle, and top layers. This makes it difficult to balance the overall performance of magic hooks, hindering the improvement of product quality and the expansion of applications.

[0004] Therefore, a three-layer co-extruded sound-absorbing magic hook formulation and its preparation method are proposed to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a formulation and preparation method for a three-layer co-extruded sound-absorbing magic hook, which solves the problem mentioned in the background technology that the overall performance of the magic hook is difficult to balance, thus restricting the quality improvement and application expansion of magic hook products.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a formulation and preparation method for a three-layer co-extruded sound-absorbing magic hook, wherein the preparation method includes the following steps: Step 1: Raw material preparation, prepare extrusion raw material mixtures for the bottom layer, middle layer and top layer respectively.

[0007] Step 2: Three-layer co-extrusion molding. The mixture of bottom, middle and top layers of raw materials prepared in Step 1 is fed into the corresponding hoppers of the three-layer co-extrusion extruder and extruded in one go through the co-extrusion die to form a sheet matrix with a three-layer structure of bottom, middle and top layers.

[0008] Step 3: Forming and cooling. The three-layer sheet substrate extruded in step 2 is passed through a forming roller to form an array of mushroom-shaped hooks on the roller surface, and then cooled and shaped to obtain a semi-finished product.

[0009] Step 4: Low-temperature multiple light pressing and shaping. The semi-finished product obtained in Step 3 is sent to the shaping device and subjected to two light pressing and shaping processes at a temperature lower than that of conventional hot pressing. This process thins and flattens the top of the mushroom head, forming a flat and thin mushroom head structure that is easy to detach. Finally, the three-layer co-extruded sound-absorbing magic hook product is obtained.

[0010] Preferably, in step one, the bottom raw material mixture consists of the following components in parts by weight: 90-99 parts PP resin, 0-5 parts color masterbatch, 0-5 parts white material, 0-5 parts functional elastomer, and 0.1-2 parts antioxidant, and no slip agent is added to the bottom raw material mixture.

[0011] The intermediate layer raw material mixture consists of the following components in parts by weight: 95-99 parts PP resin, 0-5 parts colorant, 0.1-2 parts antioxidant, and 0.1-1 parts slip agent.

[0012] The upper raw material mixture consists of the following components in parts by weight: 85-95 parts PP resin, 5-15 parts functional elastomer, 0-5 parts colorant, 0.1-1 parts antioxidant, and 0.2-2 parts slip agent.

[0013] Preferably, the PP resin is one of homopolymer polypropylene, impact-resistant polypropylene, or blends thereof; the color masterbatch is one of carbon black masterbatch, titanium dioxide masterbatch, or colored color masterbatch; the white pigment is one of calcium carbonate filler masterbatch, polyethylene wax, or a composite thereof; the colorant is one of carbon black, titanium dioxide, or phthalocyanine pigment; the antioxidant is one of hindered phenolic antioxidants, phosphite antioxidants, or blends thereof; and the slip agent is one of oleamide, erucamide, or blends thereof.

[0014] Preferably, the functional elastomer is a propylene-based elastomer, selected from one of ethylene-propylene copolymer, ethylene-propylene-diene terpolymer, or polypropylene-ethylene copolymer, and undergoes special modification treatment. The special modification treatment refers to the melt grafting reaction of the propylene-based elastomer with glycidyl methacrylate graft monomer under the action of dicumyl peroxide initiator, at a reaction temperature of 170-190°C and a reaction time of 3-8 minutes.

[0015] Preferably, in step two, the temperatures of each section of the three-layer co-extrusion extruder are set as follows: feeding section 160-180℃, compression section 180-200℃, metering section 190-210℃, die temperature 195-215℃, and extrusion speed controlled at 5-15m / min.

[0016] Preferably, in the three-layer sheet substrate formed in step two, the thickness of the bottom layer is 0.05-0.15mm, the thickness of the middle layer is 0.08-0.20mm, the thickness of the top layer is 0.04-0.12mm, and the finished product weight is 60-120g / m².

[0017] Preferably, in step three, the surface temperature of the forming roller is controlled at 40-60℃, the temperature of the cooling roller is controlled at 15-25℃, and the forming roller is provided with a concave mold that matches the shape of the mushroom head, for forming the bottom, middle and upper structure of the mushroom head.

[0018] Preferably, the mushroom-shaped hook formed in step three has the following dimensional characteristics: the bottom diameter of the mushroom head is 0.28-0.52 mm, the middle part of the mushroom head is 0.25-0.35 mm, the upper part of the mushroom head is 0.12-0.25 mm, the diameter of the mushroom head is 0.2-0.5 mm, and the thickness of the mushroom head is 0.005-0.025 mm.

[0019] Preferably, in step four, the temperature for low-temperature multiple light pressing and shaping is 80-110℃, the pressure for each light pressing is 0.2-0.5MPa, the holding time for each light pressing is 5-15 seconds, and the number of light pressing cycles is 2-5.

[0020] Preferably, the composition of the formula by weight is as follows: the bottom layer is composed of the following raw materials by weight: 90-99 parts PP resin, 0-5 parts color masterbatch, 0-5 parts white material, 0-5 parts functional elastomer, 0.1-2 parts antioxidant, and does not contain slip agent.

[0021] The intermediate layer is composed of the following raw materials in parts by weight: 95-99 parts PP resin, 0-5 parts colorant, 0.1-2 parts antioxidant, and 0.1-1 parts slip agent.

[0022] The upper layer is composed of the following raw materials in parts by weight: 85-95 parts PP resin, 5-15 parts functional elastomer, 0-5 parts colorant, 0.1-1 parts antioxidant, and 0.2-2 parts slip agent.

[0023] Compared with the prior art, the present invention provides a formulation and preparation method for a three-layer co-extruded sound-absorbing magic hook, which has the following beneficial effects: 1. In this invention, a three-layer co-extrusion structure design is adopted to achieve differentiated functional allocation among the bottom, middle, and top layers: no slip agent is added to the bottom layer to ensure good adhesion between it and the adhesive layer and to avoid slippage during winding and slitting; slip agent is added to the middle layer and PP resin is used as the main load-bearing skeleton to ensure the rigidity and uprightness of the column and prevent the mushroom head from bending and deforming; functional elastomer and slip agent are added to the top layer to give the mushroom head a soft and smooth property, reduce friction noise when detaching, and achieve a sound-absorbing effect while taking into account the overall mechanical properties.

[0024] 2. In this invention, a low-temperature, multiple light-pressing shaping process is employed. The semi-finished product is subjected to two light-pressing treatments at temperatures lower than conventional hot-pressing temperatures, causing the top of the mushroom head to gradually thin and flatten, forming a thin, flat, and easily detachable mushroom head structure. This process can fully release the internal stress of the material and avoid the problem of excessive adhesion of the mushroom head caused by high-temperature single-stage shaping. Thus, while ensuring the hooking force of the mushroom head, the noise during detachment is reduced, achieving the sound-absorbing function of the magic hook.

[0025] 3. In this invention, the functional elastomer undergoes a special modification treatment, specifically by using a propylene-based elastomer and a glycidyl methacrylate grafted monomer in a melt grafting reaction under the initiator dicumyl peroxide. This introduces polar functional groups into the elastomer molecular chain, improving its compatibility with PP resin and its softening effect on the mushroom head surface. The modified functional elastomer is uniformly dispersed in the upper layer, making the mushroom head feel softer and smoother, optimizing the smoothness and sound absorption performance of the hook, while not affecting the structural stability of the bottom and middle layers. Detailed Implementation

[0026] 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.

[0027] Example 1: Formulation and preparation method of three-layer co-extruded sound-absorbing magic hook. The preparation method includes the following steps: Step 1: Raw material preparation, prepare extrusion raw material mixtures for the bottom layer, middle layer and top layer respectively.

[0028] Step 2: Three-layer co-extrusion molding. The mixture of bottom, middle and top layers of raw materials prepared in Step 1 is fed into the corresponding hoppers of the three-layer co-extrusion extruder and extruded in one go through the co-extrusion die to form a sheet matrix with a three-layer structure of bottom, middle and top layers.

[0029] Step 3: Forming and cooling. The three-layer sheet substrate extruded in step 2 is passed through a forming roller to form an array of mushroom-shaped hooks on the roller surface, and then cooled and shaped to obtain a semi-finished product.

[0030] Step 4: Low-temperature multiple light pressing and shaping. The semi-finished product obtained in Step 3 is sent to the shaping device and subjected to two light pressing and shaping processes at a temperature lower than that of conventional hot pressing. This process thins and flattens the top of the mushroom head, forming a flat and thin mushroom head structure that is easy to detach. Finally, the three-layer co-extruded sound-absorbing magic hook product is obtained.

[0031] In step one, the bottom raw material mixture consists of the following components in parts by weight: 90 parts PP resin, 1 part color masterbatch, 1 part white material, 1 part functional elastomer, and 0.1 part antioxidant, and no slip agent is added to the bottom raw material mixture.

[0032] The intermediate layer raw material mixture consists of the following components in parts by weight: 95 parts PP resin, 1 part colorant, 0.1 part antioxidant, and 0.1 part slip agent.

[0033] The upper raw material mixture consists of the following components in parts by weight: 85 parts PP resin, 5 parts functional elastomer, 1 part colorant, 0.1 part antioxidant, and 0.2 parts slip agent.

[0034] The PP resin is homopolymer polypropylene, the color masterbatch is carbon black masterbatch, the white component is calcium carbonate filler masterbatch, the colorant is carbon black, the antioxidant is hindered phenolic antioxidant, and the slip agent is oleamide.

[0035] The functional elastomer is a propylene-based elastomer selected from ethylene-propylene copolymer and has undergone special modification treatment. The special modification treatment refers to the melt grafting reaction of the propylene-based elastomer with glycidyl methacrylate graft monomer under the action of dicumyl peroxide initiator. The reaction temperature is 170℃ and the reaction time is 3 minutes.

[0036] In step two, the temperatures of each section of the three-layer co-extrusion extruder are set as follows: feeding section 160℃, compression section 180℃, metering section 190℃, die temperature 195℃, and extrusion speed controlled at 5m / min.

[0037] In the three-layer sheet substrate formed in step two, the thickness of the bottom layer is 0.05mm, the thickness of the middle layer is 0.08mm, the thickness of the top layer is 0.04mm, and the finished product weight is 60g / m².

[0038] In step three, the surface temperature of the forming roller is controlled at 40°C, the temperature of the cooling roller is controlled at 15°C, and the forming roller is provided with a concave mold that matches the shape of the mushroom head, which is used to form the bottom, middle and top structure of the mushroom head.

[0039] In step three, the formed mushroom-shaped hook has the following dimensional characteristics: the bottom diameter of the mushroom head is 0.28 mm, the middle diameter of the mushroom head is 0.25 mm, the upper diameter of the mushroom head is 0.12 mm, the diameter of the mushroom head is 0.2 mm, and the thickness of the mushroom head is 0.005 mm.

[0040] In step four, the temperature for low-temperature multiple light pressing and shaping is 80℃, the pressure for each light pressing is 0.2MPa, the holding time for each light pressing is 5 seconds, and the number of light pressing cycles is 2.

[0041] The formula is composed of the following parts by weight: The bottom layer consists of the following raw materials in parts by weight: 90 parts PP resin, 1 part color masterbatch, 1 part white material, 1 part functional elastomer, 0.1 part antioxidant, and does not contain slip agent.

[0042] The intermediate layer is composed of the following raw materials in parts by weight: 95 parts PP resin, 1 part colorant, 0.1 part antioxidant, and 0.1 part slip agent.

[0043] The upper layer is composed of the following raw materials in parts by weight: 85 parts PP resin, 5 parts functional elastomer, 1 part colorant, 0.1 parts antioxidant, and 0.2 parts slip agent.

[0044] Example 2: Formulation and preparation method of three-layer co-extruded sound-absorbing magic hook. The preparation method includes the following steps: Step 1: Raw material preparation, prepare extrusion raw material mixtures for the bottom layer, middle layer and top layer respectively.

[0045] Step 2: Three-layer co-extrusion molding. The mixture of bottom, middle and top layers of raw materials prepared in Step 1 is fed into the corresponding hoppers of the three-layer co-extrusion extruder and extruded in one go through the co-extrusion die to form a sheet matrix with a three-layer structure of bottom, middle and top layers.

[0046] Step 3: Forming and cooling. The three-layer sheet substrate extruded in step 2 is passed through a forming roller to form an array of mushroom-shaped hooks on the roller surface, and then cooled and shaped to obtain a semi-finished product.

[0047] Step 4: Low-temperature multiple light pressing and shaping. The semi-finished product obtained in Step 3 is sent to the shaping device and subjected to two light pressing and shaping processes at a temperature lower than that of conventional hot pressing. This process thins and flattens the top of the mushroom head, forming a flat and thin mushroom head structure that is easy to detach. Finally, the three-layer co-extruded sound-absorbing magic hook product is obtained.

[0048] In step one, the bottom raw material mixture consists of the following components in parts by weight: 95 parts PP resin, 3 parts color masterbatch, 3 parts white material, 3 parts functional elastomer, and 1 part antioxidant, and no slip agent is added to the bottom raw material mixture.

[0049] The intermediate layer raw material mixture consists of the following components in parts by weight: 97 parts PP resin, 1 part colorant, 1 part antioxidant, and 0.5 parts slip agent.

[0050] The upper raw material mixture consists of the following components in parts by weight: 90 parts PP resin, 10 parts functional elastomer, 3 parts colorant, 0.5 parts antioxidant, and 1 part slip agent.

[0051] The PP resin is made of impact-resistant polypropylene, the color masterbatch is made of titanium dioxide masterbatch, the white material is made of polyethylene wax, the colorant is made of titanium dioxide, the antioxidant is made of phosphite antioxidant, and the slip agent is made of erucamide.

[0052] The functional elastomer is a propylene-based elastomer selected from ethylene-propylene-diene terpolymer and has undergone special modification treatment. The special modification treatment refers to the melt grafting reaction of the propylene-based elastomer with glycidyl methacrylate graft monomer under the action of dicumyl peroxide initiator. The reaction temperature is 180℃ and the reaction time is 5 minutes.

[0053] In step two, the temperatures of each section of the three-layer co-extrusion extruder are set as follows: feeding section 170℃, compression section 190℃, metering section 200℃, die temperature 205℃, and extrusion speed controlled at 10m / min.

[0054] In the three-layer sheet substrate formed in step two, the thickness of the bottom layer is 0.1 mm, the thickness of the middle layer is 0.15 mm, the thickness of the top layer is 0.08 mm, and the finished product weight is 90 g / m².

[0055] In step three, the surface temperature of the forming roller is controlled at 50°C, the temperature of the cooling roller is controlled at 20°C, and the forming roller is provided with a concave mold that matches the shape of the mushroom head, which is used to form the bottom, middle and top structure of the mushroom head.

[0056] In step three, the mushroom-shaped hook formed in step three has the following dimensional characteristics: the bottom diameter of the mushroom head is 0.4 mm, the middle part of the mushroom head is 0.3 mm, the upper part of the mushroom head is 0.18 mm, the mushroom head diameter is 0.3 mm, and the mushroom head thickness is 0.015 mm.

[0057] In step four, the temperature for low-temperature multiple light pressing and shaping is 100℃, the pressure for each light pressing is 0.3MPa, the holding time for each light pressing is 10 seconds, and the number of light pressing cycles is 3.

[0058] The formula is composed of the following parts by weight: The bottom layer consists of the following raw materials in parts by weight: 95 parts PP resin, 3 parts color masterbatch, 3 parts white material, 3 parts functional elastomer, 1 part antioxidant, and does not contain slip agents.

[0059] The intermediate layer is composed of the following raw materials in parts by weight: 97 parts PP resin, 1 part colorant, 1 part antioxidant, and 0.5 parts slip agent.

[0060] The upper layer is composed of the following raw materials in parts by weight: 90 parts PP resin, 10 parts functional elastomer, 3 parts colorant, 0.5 parts antioxidant, and 1 part slip agent.

[0061] Example 3: Formulation and preparation method of three-layer co-extruded sound-absorbing magic hook. The preparation method includes the following steps: Step 1: Raw material preparation, prepare extrusion raw material mixtures for the bottom layer, middle layer and top layer respectively.

[0062] Step 2: Three-layer co-extrusion molding. The mixture of bottom, middle and top layers of raw materials prepared in Step 1 is fed into the corresponding hoppers of the three-layer co-extrusion extruder and extruded in one go through the co-extrusion die to form a sheet matrix with a three-layer structure of bottom, middle and top layers.

[0063] Step 3: Forming and cooling. The three-layer sheet substrate extruded in step 2 is passed through a forming roller to form an array of mushroom-shaped hooks on the roller surface, and then cooled and shaped to obtain a semi-finished product.

[0064] Step 4: Low-temperature multiple light pressing and shaping. The semi-finished product obtained in Step 3 is sent to the shaping device and subjected to two light pressing and shaping processes at a temperature lower than that of conventional hot pressing. This process thins and flattens the top of the mushroom head, forming a flat and thin mushroom head structure that is easy to detach. Finally, the three-layer co-extruded sound-absorbing magic hook product is obtained.

[0065] In step one, the bottom raw material mixture consists of the following components by weight: 99 parts PP resin, 5 parts color masterbatch, 5 parts white material, 5 parts functional elastomer, and 2 parts antioxidant, and no slip agent is added to the bottom raw material mixture.

[0066] The intermediate layer raw material mixture consists of the following components in parts by weight: 99 parts PP resin, 5 parts colorant, 2 parts antioxidant, and 1 part slip agent.

[0067] The upper raw material mixture consists of the following components in parts by weight: 95 parts PP resin, 15 parts functional elastomer, 5 parts colorant, 1 part antioxidant, and 2 parts slip agent.

[0068] The PP resin is a blend of homopolymer polypropylene and impact-resistant polypropylene. The color masterbatch is colored masterbatch. The white material is a composite of calcium carbonate filler masterbatch and polyethylene wax. The colorant is phthalocyanine pigment. The antioxidant is a compound of hindered phenolic antioxidant and phosphite antioxidant. The slip agent is a compound of oleamide and erucamide.

[0069] The functional elastomer is a propylene-based elastomer selected from polypropylene-ethylene copolymer and has undergone special modification treatment. The special modification treatment refers to the melt grafting reaction of the propylene-based elastomer with glycidyl methacrylate graft monomer under the action of dicumyl peroxide initiator. The reaction temperature is 190℃ and the reaction time is 8 minutes.

[0070] In step two, the temperatures of each section of the three-layer co-extrusion extruder are set as follows: feeding section 180℃, compression section 200℃, metering section 210℃, die temperature 215℃, and extrusion speed controlled at 15m / min.

[0071] In the three-layer sheet substrate formed in step two, the bottom layer has a thickness of 0.15mm, the middle layer has a thickness of 0.20mm, the top layer has a thickness of 0.12mm, and the finished product has a basis weight of 120g / m².

[0072] In step three, the surface temperature of the forming roller is controlled at 60°C, the temperature of the cooling roller is controlled at 25°C, and the forming roller is provided with a concave mold that matches the shape of the mushroom head to form the bottom, middle and top structure of the mushroom head.

[0073] In step three, the mushroom-shaped hook formed in step three has the following dimensional characteristics: the diameter of the bottom of the mushroom head is 0.52mm, the diameter of the middle part of the mushroom head is 0.35mm, the diameter of the top part of the mushroom head is 0.25mm, the diameter of the mushroom head is 0.5mm, and the thickness of the mushroom head is 0.025mm.

[0074] In step four, the temperature for low-temperature multiple light pressing and shaping is 110℃, the pressure for each light pressing is 0.5MPa, the holding time for each light pressing is 15 seconds, and the number of light pressing cycles is 5.

[0075] The formula is composed of the following parts by weight: The bottom layer consists of the following raw materials in parts by weight: 99 parts PP resin, 5 parts color masterbatch, 5 parts white material, 5 parts functional elastomer, and 2 parts antioxidant, and does not contain any slip agent.

[0076] The intermediate layer is composed of the following raw materials in parts by weight: 99 parts PP resin, 5 parts colorant, 2 parts antioxidant, and 1 part slip agent.

[0077] The upper layer is composed of the following raw materials in parts by weight: 95 parts PP resin, 15 parts functional elastomer, 5 parts colorant, 1 part antioxidant, and 2 parts slip agent.

[0078] Comparative Example 1: The difference between this comparative example and Example 1 is that this comparative example does not use a three-layer co-extrusion structure.

[0079] Comparative Example 2 differs from Example 1 in that a slip agent is added to the bottom raw material in this comparative example.

[0080] Comparative Example 3 differs from Example 1 in that it does not employ a low-temperature, multiple light-pressure shaping process.

[0081] Comparative Example 4 differs from Example 1 in that the functional elastomer used in this comparative example has not undergone any special modification treatment.

[0082] The performance of the three-layer co-extruded sound-absorbing magic hooks prepared in Examples 1-3 and Comparative Examples 1-4 was tested. The test items and test methods are as follows: Peel force test: A universal testing machine was used. The magic hook sample was cut into 25mm×150mm size, bonded with standard polyester coil material, and peeled at a tensile speed of 300mm / min at 180°. The average peel force during the peeling process was recorded. Each group of samples was tested 5 times and the average value was taken.

[0083] For noise testing, in an anechoic chamber environment with background noise ≤20dB(A), the magic hook sample was peeled off from the standard ring material at a speed of 300mm / min. The peak sound pressure level during the peeling process was measured using a precision sound level meter at a distance of 30cm from the peeling point. Each sample was tested 5 times and the maximum value was taken.

[0084] For the bottom layer adhesion test, a universal testing machine was used. The hook bottom layer was bonded to a standard pressure-sensitive tape and peeled off at a tensile speed of 300 mm / min at a 180° angle. The average peel force was recorded. Each group of samples was tested 5 times and the average value was taken.

[0085] Mushroom cap size was measured by observing the cross-section of the sample using an optical microscope. The diameter of the bottom, middle, and top of the mushroom cap, as well as the thickness of the mushroom cap, were measured. Ten mushroom caps were randomly selected from each group of samples for measurement, and the average value was calculated.

[0086] The test data of the three-layer co-extruded sound-absorbing magic hooks prepared in Examples 1-3 and Comparative Examples 1-4 are recorded in Table 1 below: Table 1 - Performance Test Data of Three-Layer Co-Extruded Noise-Absorbing Magic Hook

[0087] By comparing and analyzing the data in the table, it can be seen that the three-layer co-extruded noise-absorbing magic hooks prepared using the processes in Examples 1-3 exhibit superior overall performance in terms of peel force, noise control, bottom layer adhesion, and mushroom head dimensional accuracy compared to the magic hooks prepared using the processes in Comparative Examples 1-4. This indicates that by adopting a three-layer co-extrusion structure design, differentiated functional allocation is achieved among the bottom, middle, and top layers: the bottom layer does not contain slippery agents, ensuring good adhesion between it and the adhesive layer and preventing slippage during winding and slitting; the middle layer contains slippery agents and uses PP resin as the main load-bearing skeleton to ensure the rigidity and uprightness of the column, preventing the mushroom head from bending and deforming; the top layer contains functional elastomers and slippery agents, giving the mushroom head a soft and smooth characteristic, reducing frictional noise during detachment, achieving noise reduction while also considering overall mechanical properties. By employing a low-temperature, multiple light-pressing shaping process, the semi-finished product is subjected to two light-pressing treatments at temperatures lower than conventional hot-pressing temperatures, causing the top of the mushroom head to gradually thin and flatten, forming a flat, thin, and easily detachable mushroom head structure. This process effectively releases internal material stress, preventing excessive adhesion of the mushroom-shaped hook due to high-temperature one-time setting. This reduces noise during detachment while maintaining the hook's gripping force, thus achieving the sound-absorbing function of the hook. A special modification treatment is applied to the functional elastomer: a propylene-based elastomer is melt-grafted with glycidyl methacrylate monomers under the initiator dicumyl peroxide. This introduces polar functional groups into the elastomer molecular chain, improving its compatibility with PP resin and its softening effect on the mushroom-shaped hook surface. The modified functional elastomer is uniformly dispersed in the upper layer, making the mushroom-shaped hook softer and smoother to the touch, optimizing the smoothness of the hook's opening and its sound-absorbing performance, without affecting the structural stability of the bottom and middle layers.

[0088] By comparing and analyzing the relevant data in the table, it can be seen that the three-layer co-extruded noise-absorbing magic hook prepared by the process of the present invention has high peeling force, low peeling noise, excellent bottom layer adhesion, and accurate mushroom head size control.

[0089] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, 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 limitations, 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.

[0090] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a three-layer co-extruded sound-absorbing magic hook, characterized in that: The preparation method includes the following steps: Step 1: Raw material preparation, preparing extrusion raw material mixtures for the bottom layer, middle layer and top layer respectively; Step 2: Three-layer co-extrusion molding. The mixture of bottom, middle and top layers of raw materials prepared in Step 1 is fed into the corresponding hoppers of the three-layer co-extrusion extruder and extruded in one go through the co-extrusion die to form a sheet matrix with a three-layer structure of bottom, middle and top layers. Step 3: Forming and cooling. The three-layer sheet substrate extruded in Step 2 is passed through forming rollers to form an array of mushroom-shaped hooks on the roller surface, and then cooled and shaped to obtain a semi-finished product. Step 4: Low-temperature multiple light pressing and shaping. The semi-finished product obtained in Step 3 is sent to the shaping device and subjected to two light pressing and shaping processes at a temperature lower than that of conventional hot pressing. This process thins and flattens the top of the mushroom head, forming a flat and thin mushroom head structure that is easy to detach. Finally, the three-layer co-extruded sound-absorbing magic hook product is obtained.

2. The preparation method of the three-layer co-extruded sound-absorbing magic hook according to claim 1, characterized in that: In step one, the bottom raw material mixture consists of the following components in parts by weight: 90-99 parts PP resin, 0-5 parts color masterbatch, 0-5 parts white material, 0-5 parts functional elastomer, and 0.1-2 parts antioxidant, and no slip agent is added to the bottom raw material mixture; The intermediate layer raw material mixture consists of the following components in parts by weight: 95-99 parts PP resin, 0-5 parts colorant, 0.1-2 parts antioxidant, and 0.1-1 parts slip agent; The upper raw material mixture consists of the following components in parts by weight: 85-95 parts PP resin, 5-15 parts functional elastomer, 0-5 parts colorant, 0.1-1 parts antioxidant, and 0.2-2 parts slip agent.

3. The method for preparing the three-layer co-extruded sound-absorbing magic hook according to claim 2, characterized in that: The PP resin is one of homopolymer polypropylene, impact-resistant polypropylene, or their blends; the color masterbatch is one of carbon black masterbatch, titanium dioxide masterbatch, or colored color masterbatch; the white pigment is one of calcium carbonate filler masterbatch, polyethylene wax, or their composites; the colorant is one of carbon black, titanium dioxide, or phthalocyanine pigment; the antioxidant is one of hindered phenolic antioxidants, phosphite antioxidants, or their blends; and the slip agent is one of oleamide, erucamide, or their blends.

4. The preparation method of the three-layer co-extruded sound-absorbing magic hook according to claim 2, characterized in that: The functional elastomer is a propylene-based elastomer, selected from one of ethylene-propylene copolymer, ethylene-propylene-diene terpolymer, or polypropylene-ethylene copolymer, and undergoes special modification treatment. The special modification treatment refers to the melt grafting reaction of the propylene-based elastomer with glycidyl methacrylate graft monomer under the action of dicumyl peroxide initiator, at a reaction temperature of 170-190℃ and a reaction time of 3-8 minutes.

5. The preparation method of the three-layer co-extruded sound-absorbing magic hook according to claim 1, characterized in that: In step two, the temperatures of each section of the three-layer co-extrusion extruder are set as follows: feeding section 160-180℃, compression section 180-200℃, metering section 190-210℃, die temperature 195-215℃, and extrusion speed controlled at 5-15m / min.

6. The method for preparing the three-layer co-extruded sound-absorbing magic hook according to claim 1, characterized in that: In the three-layer sheet substrate formed in step two, the thickness of the bottom layer is 0.05-0.15mm, the thickness of the middle layer is 0.08-0.20mm, the thickness of the top layer is 0.04-0.12mm, and the finished product weight is 60-120g / m².

7. The method for preparing the three-layer co-extruded sound-absorbing magic hook according to claim 1, characterized in that: In step three, the surface temperature of the forming roller is controlled at 40-60℃, the temperature of the cooling roller is controlled at 15-25℃, and the forming roller is provided with a concave mold that matches the shape of the mushroom head, which is used to form the bottom, middle part and top structure of the mushroom head.

8. The method for preparing the three-layer co-extruded sound-absorbing magic hook according to claim 1, characterized in that: The mushroom-shaped hook formed in step three has the following dimensional characteristics: the bottom diameter of the mushroom head is 0.28-0.52mm, the middle part of the mushroom head is 0.25-0.35mm, the upper part of the mushroom head is 0.12-0.25mm, the diameter of the mushroom head is 0.2-0.5mm, and the thickness of the mushroom head is 0.005-0.025mm.

9. The method for preparing the three-layer co-extruded sound-absorbing magic hook according to claim 1, characterized in that: In step four, the temperature for low-temperature multiple light pressing and shaping is 80-110℃, the pressure for each light pressing is 0.2-0.5MPa, the holding time for each light pressing is 5-15 seconds, and the number of light pressing cycles is 2-5.

10. A formulation for a three-layer co-extruded sound-absorbing magic hook, prepared by the method for preparing a three-layer co-extruded sound-absorbing magic hook according to any one of claims 1-9, characterized in that: The composition by weight of the formula is as follows: The bottom layer is composed of the following raw materials in parts by weight: 90-99 parts PP resin, 0-5 parts color masterbatch, 0-5 parts white material, 0-5 parts functional elastomer, 0.1-2 parts antioxidant, and does not contain slip agent; The intermediate layer is composed of the following raw materials in parts by weight: 95-99 parts PP resin, 0-5 parts colorant, 0.1-2 parts antioxidant, and 0.1-1 parts slip agent; The upper layer is composed of the following raw materials in parts by weight: 85-95 parts PP resin, 5-15 parts functional elastomer, 0-5 parts colorant, 0.1-1 parts antioxidant, and 0.2-2 parts slip agent.

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