Peelable PU gum for artificial turf and preparation method of peelable PU gum

Abstract

The invention belongs to the technical field of artificial turf manufacturing, and particularly discloses peelable PU gum for artificial turf and a preparation method of the peelable PU gum, and the peelable PU gum comprises a polyester type PU prepolymer, thermoplastic acrylic resin, blocked isocyanate, methyl silicone oil, PEG-400, a mixed solvent and an antioxidant. The back adhesive is firm in normal-temperature bonding, can be stripped in a whole piece at 120 DEG C or above, has high weather resistance and multi-base-layer adaptability, and is suitable for multi-scene environment-friendly artificial turf.

Description

Technical Field

[0001] This invention belongs to the field of artificial turf manufacturing technology, specifically a peelable PU adhesive backing for artificial turf and its preparation method. Background Technology

[0002] Artificial turf is widely used in sports stadiums, landscaping, kindergarten grounds, and temporary activity areas due to its advantages such as excellent weather resistance, low maintenance costs, and long service life. The adhesive backing, as a core component of artificial turf, has the core function of fixing the grass fibers to the base fabric, ensuring the overall structural stability of the turf, while also meeting requirements for ease of installation, safety in use, environmental compliance, and adaptability to different application scenarios.

[0003] Currently, most artificial turf backing adhesives on the market are non-removable systems. In temporary site installations, site renovations, or turf recycling, these systems present problems such as adhesive residue on the substrate surface, damage to the substrate during cleaning, and increased subsequent maintenance costs. Some backing adhesives use polyether-based PU or traditional high-VOC solvent systems, which not only exhibit significant fluctuations in bond strength at high temperatures but may also fail to fully meet current environmental policies and the environmental requirements of high-end applications due to high VOC emissions.

[0004] To address the market demand for peelable adhesive backings, existing technologies mostly achieve peelability by adding release agents. However, there is a challenge in balancing room-temperature adhesive strength and high-temperature peelability. Peelability is affected by factors such as ambient temperature and substrate material, and its stability needs improvement. Furthermore, existing formulations have limited adaptability to specific needs in extended applications such as electronic process protection, automotive paint masking, and food packaging, including solvent resistance, food-grade safety, and precise peeling temperature control. This restricts the application expansion of peelable PU adhesive backings in artificial turf and other related fields. For example, patent CN108824128A discloses a recyclable artificial turf that uses a water-based polyolefin dispersion as the main component of the adhesive layer, prepared through a two-coating and baking process. This solution emphasizes the compatibility of the adhesive layer during recycling and re-firing, and exhibits good water resistance. However, the patent does not address the design of the peelable properties of the adhesive layer, nor does it optimize key parameters such as peel force control, peel temperature window, and substrate compatibility. Its adhesive system focuses more on the reprocessing performance in the recycling process, rather than the controllable peeling requirements in temporary laying or easy disassembly scenarios.

[0005] In addition, patent CN104060519A discloses an artificial turf manufacturing process that uses a thermoplastic material as the backing layer. After coating and cooling the backing layer on the back of the base fabric, the base fabric is separated from the backing layer, allowing the grass fibers to adhere directly to the backing layer, thus achieving overall recyclability. This process achieves structural "separability" by selecting a thermoplastic material with poor adhesion to the base fabric. However, the "separability" of this solution relies on the weak interfacial bonding between the base fabric and the backing layer, rather than being based on the temperature-responsive peeling mechanism of the backing itself. Furthermore, it does not use a polyurethane (PU) system and does not systematically control indicators such as peel strength, heat resistance, and environmental friendliness, making it difficult to meet the diverse application scenarios with specific requirements for peel performance.

[0006] In summary, while the two existing technologies mentioned above have certain advantages in terms of the mechanical properties, aging resistance, and water resistance of PU backing adhesives, they do not yet provide effective solutions in terms of peelability, environmental friendliness, temperature responsiveness, and adaptability to various scenarios. Therefore, they cannot meet the functional requirements of artificial turf backing adhesives for temporary, recyclable, or environmentally friendly applications. Thus, developing a PU backing adhesive system that combines controllable peelability, good adhesive strength, and environmental adaptability has significant technological advancement and market application value. Summary of the Invention

[0007] This invention provides a peelable PU adhesive backing for artificial turf and its preparation method. It aims to solve the core problems of existing technologies, such as serious residue of non-peelable backing, difficulty in balancing room temperature bonding strength and high temperature peeling performance, and uncontrollable peeling temperature window, by constructing a composite adhesive system with polyester-type PU prepolymer as the main body, thermoplastic acrylic resin as the temperature-responsive component, and blocked isocyanate as the latent curing agent.

[0008] In a first aspect, the present invention provides a peelable PU adhesive backing for artificial turf, comprising, by weight, the following components: 100 parts of polyester-type PU prepolymer; 20-30 parts of thermoplastic acrylic resin; 10 parts of polyethylene glycol PEG-4005; 1-3 parts methyl silicone oil; 3-10 parts of blocked isocyanate; Mixed solvent 100-200 parts; Antioxidant 0.5-2 parts.

[0009] In the formulation system of this invention, polyester-type PU prepolymer serves as the main film-forming material. Its molecular chain contains numerous ester bonds, and compared to polyether-type PU prepolymer, polyester-type PU exhibits higher cohesive energy density and crystallization tendency, thus endowing the adhesive with excellent initial bond strength and heat resistance stability. PU prepolymer blending adjusts the cohesive strength and toughness of the adhesive layer. Blocked isocyanate, acting as a latent curing agent, protects its active -NCO groups at room temperature with blocking agents (such as caprolactam, methyl ethyl ketone oxime, or phenolic compounds), preventing reaction with hydroxyl groups or moisture in the system and ensuring the stability of the adhesive during storage and coating. When the temperature rises to 110°C to 130°C, the blocking agent dissociates, releasing active isocyanate groups, which crosslink with the hydroxyl groups at the ends of the polyester-type PU prepolymer or residual moisture in the system, forming a three-dimensional network structure and improving the heat resistance, solvent resistance, and structural integrity of the adhesive. This crosslinking reaction occurs only during the high-temperature curing stage and does not affect the peel performance design at room temperature. Furthermore, polyethylene glycol PEG-400, as a flexible segment introduced into the system, has a moderate molecular weight. It improves the compatibility between the PU prepolymer and acrylic resin, reduces micro-phase separation, and forms a micro-regional plasticizing effect in the cured film, adjusting the smoothness of the peel force curve and preventing abrupt breakage or residue during peeling. Simultaneously, PEG-400 contains terminal hydroxyl groups, which can react with the unsealed isocyanate groups at high temperatures, participating in the construction of the cross-linking network, enhancing cohesive strength at high temperatures, and preventing excessive flow or exudation of the adhesive before peeling. Methyl silicone oil migrates to the adhesive / base layer interface in the system, reducing the interfacial surface energy and forming a weak boundary layer. However, unlike the passive isolation mechanism of traditional release agents, the silicone oil in this invention has a certain degree of physical entanglement with the PU matrix. It does not significantly weaken the adhesive force at room temperature, but only accumulates at the interface due to increased molecular thermal motion at high temperatures. This, combined with the softening effect of the thermoplastic resin, achieves a reversible switching between the "adhesive-peel" state. Furthermore, the introduction of silicone oil helps improve the adhesive's adaptability to various substrates such as concrete, asphalt, and metal. Antioxidants are used to inhibit the thermo-oxidative aging of the PU backbone during processing and use, extending the adhesive's service life, especially maintaining performance stability in high-temperature peel cycle tests.

[0010] Preferably, the mass ratio of the polyester-type PU prepolymer, thermoplastic acrylic resin and blocked isocyanate is 100:(20-27):7.

[0011] In this invention, the mass ratio of polyester-type PU prepolymer, thermoplastic acrylic resin, and blocked isocyanate is controlled at 100:(20-27):7. This ratio has been verified through extensive experiments to achieve an optimal balance between room temperature peel strength (≥15-28 N / mm) and high temperature peel strength (≤3 N / 25 mm, tested at 120°C). If the proportion of thermoplastic acrylic resin is less than 20 parts, the high-temperature softening effect is insufficient, making peeling difficult; if it is more than 30 parts, the room temperature adhesion strength decreases significantly. A low proportion of blocked isocyanate results in insufficient crosslinking density, while a high proportion leads to a rebound in peel strength.

[0012] Preferably, the NCO content of the polyester-type PU prepolymer is 3%-5%.

[0013] In this invention, a polyester-type PU prepolymer with an NCO content of 3%-5% is selected. This NCO content range ensures sufficient reactivity of the prepolymer during subsequent curing while avoiding decreased storage stability or increased VOC release due to excessively high NCO content. The polyester structure exhibits higher cohesive strength, heat resistance, and hydrolysis resistance compared to the polyether structure, providing a mechanical basis for the long-term outdoor use of the adhesive. In other words, the NCO content affects the room-temperature adhesion and high-temperature peel performance of the peelable PU adhesive; both excessive and insufficient NCO content will cause a decline in these properties.

[0014] Preferably, the glass transition temperature (Tg) of the thermoplastic acrylic resin is 50°C-60°C.

[0015] In this invention, thermoplastic acrylic resin, as a temperature-responsive regulating component, is a copolymer of methyl methacrylate, styrene, butyl acrylate, acrylic acid, etc. By controlling 60-65% methyl methacrylate (MMA), 7-10% butyl acrylate (BA), 20-25% styrene (ST), and 2%-4% acrylic acid, the Tg of the thermoplastic acrylic resin is controlled within the range of 50℃-60℃. This ensures that the adhesive backing remains in a glassy state at room temperature (23℃±2℃), maintaining a high modulus and adhesion. When the ambient temperature rises above 100℃, the resin softens and enters a highly elastic state, resulting in a significant decrease in the overall adhesive layer modulus, thereby reducing the interfacial bonding force with the substrate and achieving controllable peeling. Controlling the Tg value within the 50℃-60℃ range achieves a perfect balance between the two key properties of room temperature bonding and high-temperature peeling. A low transition temperature will reduce both room temperature bonding and high-temperature peeling performance, while a high temperature will affect the glass temperature. Peeling at 120℃ will leave adhesive residue, requiring a higher peeling temperature for complete peeling. This temperature range also provides better flexibility, allowing it to adapt to minor deformations on the substrate surface and improving bonding reliability. Furthermore, controlling the Tg value of the thermoplastic acrylic resin within the 50-60℃ range ensures that the adhesive maintains stable adhesion at room temperature, while softening and reducing bond strength at high temperatures.

[0016] Preferably, the methyl silicone oil is at least one of methylphenyl silicone oil and dimethyl silicone oil. More preferably, the methyl silicone oil is dimethyl silicone oil with a viscosity of 50 to 100 centistokes.

[0017] Preferably, the antioxidant is antioxidant 1010.

[0018] Preferably, the mixed solvent is composed of ethyl acetate and butanone in a mass ratio of 3:(1-1.5).

[0019] In this invention, the mixed solvent is a mixture of ethyl acetate and methyl ethyl ketone (MEK) at a mass ratio of 3:(1-1.5). This combination has a suitable evaporation rate gradient: ethyl acetate has a boiling point of 77°C and evaporates relatively quickly, which is beneficial for initial surface drying; MEK has a boiling point of 80°C, is highly polar, and has good solubility for both PU and acrylic resins, which can slow down the overall drying speed and prevent the adhesive layer from forming a skin too quickly, leading to internal solvent retention. The VOC content of this solvent system is less than 300 g / L, which meets the limit requirements for adhesives in GB / T 38597-2020 "Technical Requirements for Coatings with Low Volatile Organic Compound Content".

[0020] Preferably, the blocked isocyanate is hexamethylene diisocyanate (HDI-BDO-Caprolactam) blocked with caprolactam, with a deblocking temperature of approximately 120℃-130℃, matching the temperature of the later stage of the coating and curing process. During room temperature storage and construction, the isocyanate groups are blocked, and the system maintains single-component stability. In the high-temperature section of the drying tunnel, the blocker dissociates, releasing active NCO groups, which react with the residual hydroxyl groups in the system (from the PU prepolymer and PEG-400) to form a three-dimensional network. This crosslinking reaction is not complete curing, but rather constructs a "thermally reversible" or "thermally weakened" network structure, allowing partial breakage of the crosslinking points under subsequent higher temperatures (such as above 120℃) or mechanical action, achieving controllable peeling.

[0021] In a second aspect, the present invention provides a method for preparing a peelable PU adhesive as described in the first aspect, comprising the following steps: S1. Under an inert atmosphere, add the polyester-type PU prepolymer to 70% of the mixed solvent and stir at 300-500 r / min for 40-60 minutes at 30℃-40℃ to form a transparent and homogeneous solution; S2. Slowly add the thermoplastic acrylic resin in powder or granule form to the above solution, control the temperature of the reactor at 50℃-55℃, maintain the stirring speed at 400-600r / min, and continue stirring for 30-40 minutes to make the resin completely swell and disperse evenly, and the system is milky white and semi-transparent. S3. Add polyethylene glycol PEG-400 and methyl silicone oil to the reactor in sequence, and continue stirring at 50℃-55℃ for 15-20 minutes to ensure that the additives are fully dispersed and there is no local enrichment. S4. After pre-mixing the blocked isocyanate and antioxidant evenly, add them to the reaction vessel and disperse them at a high speed of 600-1000 r / min for 30-40 minutes to form a stable, sediment-free adhesive system. During this process, maintain an inert atmosphere to prevent moisture intrusion and pre-crosslinking. S5. Add the remaining 30% of the mixed solvent in batches to adjust the viscosity of the system to 8000-12000 mPa·s (25℃, measured by rotational viscometer) to obtain the finished adhesive backing. Seal and store in a cool, dry place with a shelf life of not less than 6 months.

[0022] In the preparation process of this invention, the polyester-type PU prepolymer is first mixed with most of the solvent at low temperature to prevent self-polymerization of the prepolymer; then, thermoplastic acrylic resin is added at a higher temperature to allow it to fully swell and disperse without phase separation; next, polyethylene glycol and methyl silicone oil are added sequentially to ensure uniform distribution of functional additives; finally, blocked isocyanate and antioxidant are introduced under high-speed shearing to prevent excessive local concentrations from causing side reactions. The viscosity adjustment stage uses a batch-addition of solvent to precisely control the rheological properties during application and adapt to different coating equipment. After coating, a stepped heating and drying process is used: the initial low temperature stage removes low-boiling-point solvents, while the subsequent high temperature stage promotes the deblocking and cross-linking reaction of the blocked isocyanate, forming a gradient adhesive layer that combines strong adhesion at room temperature with easy peeling at high temperature.

[0023] This technical solution constructs a temperature-responsive reversible bonding system through component design and process synergy, eliminating the need for additional release agents and avoiding the performance degradation problem caused by release agent migration in traditional peelable adhesives. At the same time, it adopts a low-VOC solvent system, which complies with environmental regulations. It exhibits a stable peel window on a variety of base materials and is suitable for various applications such as temporary sports venues, rooftop greening renovations, and lawn recycling.

[0024] Thirdly, this invention provides a coating and curing method for a peelable PU adhesive backing for artificial turf, specifically comprising: uniformly coating the finished adhesive backing onto the back of the artificial turf base fabric using a scraper coater or roller coater, with the coating amount controlled at 300-1000 g / m²; immediately placing the coated turf into a drying tunnel and drying it for 5-15 minutes at a temperature range of 90℃-130℃, wherein the initial temperature is controlled at 90℃-100℃ to promote solvent evaporation, and the subsequent temperature is raised to 120℃-130℃ to activate the desealing reaction of the blocked isocyanate, completing the cross-linking and curing; the cured adhesive backing forms a dense, continuous film layer with a thickness of 0.3-0.8 mm, which fully penetrates and anchors to the roots of the grass fibers and the base fabric fibers. Specifically, the base fabric is a polypropylene woven fabric with a basis weight of 200 g / m² and a porosity of 65%.

[0025] Fourthly, this invention provides a peelable PU-backed environmentally friendly artificial turf, comprising grass fibers, a base fabric, and the aforementioned peelable PU backing; the backing is coated on the back of the base fabric to fix the grass fibers to the base fabric, and meets the performance indicators of a peel strength of ≥15N / 25mm at room temperature and a peel strength of ≤3N / 25mm at 120℃. The grass fibers are PE / PP blended monofilaments with a linear density of 12000 dtex and a height of 40mm.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention constructs a peelable PU adhesive system that combines high adhesive strength at room temperature, low peel strength at high temperature, high heat resistance, and adaptability to multiple scenarios. This system abandons the traditional peeling strategy that relies on a large amount of release agent, and instead adopts a dynamic balance mechanism of glass transition behavior of thermoplastic resin and latent curing crosslinking network to achieve precise control of peel performance. At the same time, the polyester PU backbone and the closed isocyanate crosslinking structure together ensure the structural stability of the adhesive in the non-peeling state, and solve the technical contradiction of "strong adhesion" and "easy peeling" that cannot be achieved simultaneously in the prior art.

[0027] (2) Through the above component design and process control, the present invention constructs a PU backing adhesive system that has high bonding strength at room temperature, controllable peeling at high temperature and good substrate compatibility. It solves the problems of non-peelability, unstable peeling, poor environmental performance and insufficient scene adaptability in the prior art. It is suitable for application scenarios with clear requirements for easy disassembly and non-destructive removal, such as temporary sports events in sports venues, kindergarten site renovation, and rapid turf laying for exhibition activities. Detailed Implementation

[0028] The various embodiments or implementation schemes in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments.

[0029] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0031] The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially. Among them, the antioxidant is antioxidant 1010, the methyl silicone oil is dimethyl silicone oil, and the grass fibers are PE / PP blend monofilaments with a linear density of 12000 dtex and a height of 40 mm.

[0032] Example 1 This embodiment provides a method for preparing a peelable PU adhesive backing for artificial turf, comprising the following steps: S1. Weigh 100g of polyester PU prepolymer (NCO content 4.2%), 25g of thermoplastic acrylic resin (Tg=55℃), 8g of polyethylene glycol PEG-400, 2g of dimethyl silicone oil, 7g of caprolactam-blocked hexamethylene diisocyanate, 10101g of antioxidant, and 160g of mixed solvent (120g of ethyl acetate + 40g of butanone). Add the PU prepolymer to the reactor, add 112g of mixed solvent, and stir at 35℃ and 400r / min for 50 minutes. S2. Add acrylic resin powder and stir at 52℃ and 500r / min for 30 minutes to make the resin completely swell and disperse evenly, and the system is milky white and semi-transparent. S3. Add polyethylene glycol PEG-400 and dimethyl silicone oil (pre-diluted with 20g ethyl acetate), stir at 52℃ for 15 minutes to ensure that the additives are fully dispersed and there is no local enrichment. S4. Add caprolactam-blocked hexamethylene diisocyanate and antioxidant 1010 premix and disperse at 800 r / min for 30 minutes to form a stable, non-settling adhesive system. During this process, maintain a nitrogen atmosphere to prevent moisture intrusion and pre-crosslinking. S5. Add the remaining 48g of mixed solvent in batches and adjust the viscosity to 10000mPa·s to obtain the finished adhesive backing.

[0033] Artificial turf preparation: The finished adhesive is evenly coated onto the back of the artificial turf base fabric at 700g / m² using a scraper coating machine, and then cured at 90℃ / 2min→110℃ / 3min→130℃ / 5min to obtain the finished turf.

[0034] Example 2 Except that the amount of thermoplastic acrylic resin is 20g and Tg=52℃, the rest is the same as in Example 1.

[0035] Example 3 Except that the amount of thermoplastic acrylic resin is 27g and Tg=58℃, the rest is the same as in Example 1.

[0036] Example 4 Except that the NCO content of the polyester-type PU prepolymer is 3.5% and the amount of mixed solvent is 180g, the rest is the same as in Example 1.

[0037] Comparative Example 1 Adhesive formulation: 100g SBR emulsion, 20g rosin resin, 150g toluene, the rest are the same as in Example 1.

[0038] Comparative Example 2 Adhesive formulation: 100g polyether-type PU prepolymer (NCO content 4.2%), 25g acrylic resin, 6g caprolactam-blocked hexamethylene diisocyanate, 160g mixed solvent, the rest are the same as in Example 1.

[0039] Comparative Example 3 The thermoplastic acrylic resin in the formulation of Example 1 has a Tg of 75°C, and the rest is the same as in Example 1.

[0040] Comparative Example 4 In the formulation of Example 1, the thermoplastic acrylic resin was removed, the proportions of the remaining components remained unchanged, and the solvent was added to make up to the same total amount.

[0041] Comparative Example 5 In the formulation of Example 1, the blocked isocyanate was removed, and the rest was the same as in Example 1.

[0042] Comparative Example 6 The mass of the thermoplastic acrylic resin in the formulation of Example 1 is 35g, and the rest is the same as in Example 1.

[0043] Comparative Example 7 The mass of the thermoplastic acrylic resin in the formulation of Example 1 is 15g, and the rest is the same as in Example 1.

[0044] The artificial turf prepared in the above embodiments and comparative examples was tested for performance using the aforementioned method, and the results are shown in Table 1 below.

[0045] The room temperature peel strength test was conducted according to GB / T 2790-1995 standard. Under the conditions of 23℃ and 50%RH, the turf backing was bonded to a standard stainless steel plate (SUS304, surface roughness Ra=0.8μm), and the test was carried out at a peel angle of 180° and a speed of 300mm / min after 24 hours.

[0046] The method for high-temperature peel strength test at 120℃ is as follows: place the bonded sample in a 120℃ forced-air oven and keep it at a constant temperature for 1 hour, then immediately take it out and complete the peel test within 10 seconds.

[0047] Table 1 Test performance of artificial turf prepared in the examples and comparative examples As shown in Table 1, the adhesive prepared in the embodiments of the present invention exhibits high bonding strength at room temperature, but the peel strength decreases significantly at 120°C, with the decrease exceeding 84%. Comparative Example 1, using an SBR system, shows poor peel performance. Comparative Example 2, using polyether-type PU, exhibits significantly inferior high-temperature peel performance compared to the present invention. Comparative Example 3, using thermoplastic acrylic resin with a Tg of 75°C, shows significantly worse peel strength at both room temperature and high-temperature peel performance compared to the present invention.

[0048] Data from Example 1 and Comparative Examples 4 and 5 show that Comparative Examples 4 and 5, due to the absence of thermoplastic acrylic resin or blocked isocyanate respectively, have significantly deteriorated high-temperature peel performance, proving that the synergistic effect of the two is crucial to achieving the "adhesive-peel" switching.

[0049] Data from Example 1, Comparative Examples 6 and 7 show that when the proportion of thermoplastic acrylic resin is higher than 30 parts, the adhesion at room temperature decreases significantly; when the proportion of thermoplastic acrylic resin is lower than 20 parts, the high-temperature softening effect is insufficient, and peeling is difficult.

[0050] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A peelable PU adhesive backing for artificial turf, characterized in that, By weight, it includes the following components: 100 parts of polyester-type PU prepolymer; 20-30 parts of thermoplastic acrylic resin; 10 parts of polyethylene glycol PEG-4005; 1-3 parts methyl silicone oil; 3-10 parts of blocked isocyanate; Mixed solvent 100-200 parts; Antioxidant 0.5-2 parts.

2. The peelable PU adhesive backing for artificial turf according to claim 1, characterized in that, The NCO content in the polyester-type PU prepolymer is 3%-5%.

3. The peelable PU adhesive backing for artificial turf according to claim 1, characterized in that, The glass transition temperature (Tg) of the thermoplastic acrylic resin is 50℃-60℃.

4. The peelable PU adhesive backing for artificial turf according to claim 1, characterized in that, The mixed solvent is composed of ethyl acetate and butanone in a mass ratio of 3:(1-1.5).

5. The peelable PU adhesive backing for artificial turf according to claim 1, characterized in that, The blocked isocyanate is caprolactam-blocked hexamethylene diisocyanate.

6. The peelable PU adhesive backing for artificial turf according to claim 1, characterized in that, The methyl silicone oil is at least one of methylphenyl silicone oil and dimethyl silicone oil.

7. The peelable PU adhesive backing for artificial turf according to claim 1, characterized in that, The antioxidant is antioxidant 1010.

8. A method for preparing a peelable PU adhesive backing for artificial turf as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Under an inert atmosphere, add polyester-type PU prepolymer to 70% of the mixed solvent and stir at 300-500 r / min for 40-60 minutes at 30℃-40℃ to form a transparent and homogeneous solution. S2. Add thermoplastic acrylic resin to the solution obtained in S2, control the temperature at 50℃-55℃, maintain the stirring speed at 400-600r / min, and continue stirring for 30-40 minutes to make the resin completely swell and disperse evenly. S3. Then add polyethylene glycol PEG-400 and methyl silicone oil in sequence, and stir at 50℃-55℃ for 15-20 minutes. S4. After pre-mixing the blocked isocyanate and antioxidant evenly, add them to the system of step S4 and disperse at high speed at 600-1000 r / min for 30-40 minutes, while maintaining an inert atmosphere. S5. Add the remaining 30% of the mixed solvent in batches and adjust the viscosity of the system to 8000-12000 mPa·s to obtain the finished adhesive backing.

9. A method for coating and curing a peelable PU adhesive backing for artificial turf, characterized in that, The process includes the following steps: applying the finished adhesive obtained in claim 8 evenly to the back of the artificial turf base fabric using a scraper coating machine or a roller coating machine, with a coating amount of 300-1000 g / m²; the coated turf is then placed in a drying tunnel and dried at 90℃-130℃ for 5-15 minutes, with the initial temperature being 90℃-100℃ and the subsequent temperature being 120℃-130℃.

10. An artificial turf, characterized in that, It includes grass fibers, a base fabric, and a peelable PU adhesive backing as described in any one of claims 1 to 7 for artificial turf; the adhesive backing is coated on the back of the base fabric to fix the grass fibers to the base fabric.

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