Ultrahigh-stripping-force acrylate pressure-sensitive adhesive for TPU (thermoplastic polyurethane) car cover film and preparation method of ultrahigh-stripping-force acrylate pressure-sensitive adhesive

Abstract

The invention discloses an ultrahigh-stripping-force acrylate pressure-sensitive adhesive for a TPU (Thermoplastic Polyurethane) car cover film and a preparation method of the ultrahigh-stripping-force acrylate pressure-sensitive adhesive, and relates to an ultrahigh-stripping-force acrylate pressure-sensitive adhesive and a preparation method thereof. The invention aims to solve the problem that the traditional automobile cover film pressure-sensitive adhesive is difficult to balance between ultrahigh stripping force and high cohesive strength. The adhesive is formed by copolymerizing a (methyl) acrylate soft monomer, a hard monomer and a bifunctional monomer containing hydroxyl and carboxyl. According to the preparation method, a solution free radical polymerization process is adopted, and the size of polymerization molecular weight is controlled by controlling the monomer feeding sequence and proportion. The obtained pressure-sensitive adhesive has extremely high stripping force on a paint surface, and also has excellent cohesive strength, weather resistance and residual adhesive resistance, so that the TPU vehicle cover film can be permanently and firmly adhered, is free of residues during removal, and has excellent comprehensive performance. The invention belongs to the technical field of pressure-sensitive adhesives.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of super high peeling force acrylate pressure sensitive adhesive and its preparation method, belong to pressure sensitive adhesive technical field. BACKGROUND

[0002] The paint protection film, commonly known as "car clothes", is a kind of high-performance transparent film pasted on the paint of the car, which mainly protects the original car paint from stone scratches, acid rain corrosion, ultraviolet aging and daily minor scratches. Thermoplastic polyurethane elastomer has become the first choice of high-end paint protection film due to its excellent flexibility, transparency, weather resistance, yellowing resistance and self-repairing performance.

[0003] As a key component of the paint protection film, the performance of the pressure sensitive adhesive directly determines the adhesion effect of the film and the paint, the convenience of construction, the long-term durability and the final protection effect. Acrylate pressure sensitive adhesive is widely used in such products due to its excellent weather resistance, transparency and environmental friendliness.

[0004] However, traditional acrylate pressure sensitive adhesive faces a key technical challenge when applied to TPU car film: the balance between peeling force and cohesive strength. Specifically, in order to ensure the perfect adhesion of TPU car film on complex curved surfaces and avoid the phenomenon of residual glue caused by cohesive failure of the adhesive layer after long-term use, the pressure sensitive adhesive is required to have extremely high comprehensive performance: 1. Super high peeling force: It is necessary to provide high initial adhesion (initial adhesion) and final adhesion (peeling force) to ensure that the film and the paint are firmly combined, and do not occur edge lifting, overall displacement or even falling off in harsh environments such as high-speed driving, rain and wind washing or car washing.

[0005] 2. High cohesive strength: The adhesive layer must have extremely high cohesive strength and creep resistance to withstand long-term stress. Insufficient cohesive strength will cause cohesive failure of the adhesive layer when the film is removed, leaving residual glue on the paint surface, which seriously damages the value of the vehicle, which is one of the most fatal defects of car film products.

[0006] 3. Excellent weather resistance and aging resistance: The adhesive layer must remain stable in performance when exposed to ultraviolet light, high temperature and high humidity for a long time outdoors, without yellowing, fogging, degradation or dramatic changes in adhesion.

[0007] In the prior art, in order to improve the peeling force of acrylate pressure sensitive adhesive, the commonly used methods include increasing the coating thickness of the adhesive layer, adding high-polarity monomers or introducing crosslinking agents. However, these methods have obvious limitations: (1) Increase the coating thickness: Although it can temporarily improve the adhesion, it will significantly increase the cost and may cause appearance defects such as bubbles and orange peel during adhesion, affecting the appearance.

[0008] (2) Add high-polarity monomers such as acrylamide, which can enhance adhesion, but excessive addition will damage the cohesive strength of the glue and may cause the glue layer to become hard and brittle, making it more prone to break under dynamic stress.

[0009] (3) Introduce crosslinking agents: chemical crosslinking can improve cohesive strength, but traditional crosslinking systems (such as metal chelates) often have problems with crosslinking speed and control difficulty. Insufficient crosslinking will limit the improvement of cohesive strength; excessive crosslinking will make the glue layer brittle, and the peeling force will drop sharply, even losing pressure-sensitive properties, leading to poor adhesion.

[0010] Therefore, the acrylate pressure-sensitive adhesive in the prior art cannot simultaneously achieve the perfect balance between "ultra-high peeling force" and "ultra-high cohesive strength" in the specific application scenario of TPU car film. The peeling force of most products on the market still has room for improvement, and there is a risk of insufficient durability and anti-residue performance.

[0011] In summary, there is an urgent need in the art to develop a new type of acrylate pressure-sensitive adhesive and its preparation method, which is specifically used for TPU car film and can achieve ultra-high peeling force without sacrificing cohesive strength, weather resistance, and application suitability, thereby meeting the increasingly stringent requirements of the high-end automotive paint protection market for product performance. SUMMARY

[0012] To solve the problem of balancing between ultra-high peeling force and high cohesive strength of traditional car film pressure-sensitive adhesive, the present application proposes an ultra-high peeling force acrylate pressure-sensitive adhesive for TPU car film and its preparation method.

[0013] The technical solution adopted by the present application to solve the above problems is as follows: the mass fraction of each component of the ultra-high peeling force acrylate pressure-sensitive adhesive for TPU car film is as follows: soft monomer 60-80 parts, hard monomer 30-50 parts, functional monomer 5-20 parts, initiator 0.1-0.5 parts, crosslinking agent 0.1-0.5 parts, and organic solvent 50-300 parts.

[0014] Further, the soft monomer is any one or several of ethyl acrylate, butyl acrylate, isooctyl acrylate, and lauryl methacrylate. The hard monomer is any one or several of methyl acrylate, vinyl acetate, t-butyl acrylate, and isobornyl methacrylate.

[0015] Further, the functional monomer is any one or several of acrylic acid, isooctyl acrylate, hydroxybutyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate.

[0016] Further, the initiator is any one or several of dibenzoyl peroxide, azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptonitrile; The organic solvent is any one or several of ethyl acetate, cyclohexane, toluene, isopropyl alcohol.

[0017] Further, the crosslinking agent is any one or several of metal chelate, amino resin, isocyanate, aziridine and epoxy.

[0018] The steps of the preparation method of the super-high peel strength acrylate pressure-sensitive adhesive for TPU car film include: Step 1, mix soft monomers, hard monomers and functional monomers into a mixture, divide the mixture into a part a and a part b, add organic solvent to part a and stir and add initiator to part a and stir in a reaction kettle, add organic solvent to part b and stir and mix with initiator and place in a high-position dropping tank; wherein part a is 60% to 80% and part b is 40% to 20%; Step 2, then pass nitrogen, continue to heat, and stop heating when the explosive polymerization state in the reaction kettle stops; Step 3, after waiting for 15 minutes for the reaction temperature to be stable, start uniform dropping of the high-position dropping tank and complete dropping within 120 minutes, then perform heat preservation, then add a mixed solution of initiator and organic solvent, perform uniform dropping and complete dropping within 30 minutes, and continue heat preservation for 4 hours; Step 4, add organic solvent, cool down, add a composite crosslinking agent, and finally stir to obtain the acrylate pressure-sensitive adhesive.

[0019] Further, the mass of the organic solvent added to part a in step 1 is 60%, the mass of the organic solvent and initiator added to the high-position tank in part b is 30% and 60%, the mass of the organic solvent and initiator in step 3 is 10% and 40%, the mass of the organic solvent in step 4 is 10%, and the cooling down refers to cooling down to 45℃.

[0020] Further, the stirring speed in steps 1 to 4 is all 110 r / min, and the composite crosslinking agent is any one or several of metal chelate, amino resin, isocyanate, aziridine and epoxy.

[0021] Further, the use method of the acrylate pressure-sensitive adhesive is as follows: coat the pressure-sensitive adhesive on a PET release film, dry, then transfer to a TPU base film or directly coat on a PET base film, place in an oven for curing, and then the acrylate pressure-sensitive adhesive tape is obtained.

[0022] Further, the thickness of the coating on the PET release film is 15 μm, the thickness of the TPU base film is 50 μm respectively, and the temperature and time of the curing are 60 °C and 48 h respectively.

[0023] The beneficial effects of the present application are: (1) The perfect balance of ultrahigh peeling force and high cohesive strength is achieved: Through the precise ratio design of soft and hard monomers, on the one hand, the pressure-sensitive adhesive can exhibit extremely high peeling force on the car paint surface, ensuring the extremely firm pasting effect of the car cover film and effectively preventing edge warping and overall falling. On the other hand, the adhesive itself has extremely high cohesive strength and modulus. When subjected to peeling stress, the failure mode is a healthy balance between cohesive failure and interfacial adhesion failure, thus fundamentally eliminating the residue phenomenon when removed, achieving the ideal effect of "strong adhesion and clean tearing".

[0024] (2) Excellent durability and weather resistance: The pressure-sensitive adhesive system prepared by the present application has excellent anti-creeper performance and aging resistance. Its high molecular chain structure is stable, can withstand harsh environmental tests such as ultraviolet radiation, high temperature and humidity, and cold and hot cycles for a long time, effectively avoiding performance degradation due to aging, softening or degradation of the adhesive layer, and ensuring the long-lasting protection life of the car cover film for several years. At the same time, the adhesive layer has high transparency and excellent yellowing resistance, which will not affect the original color of the car body.

[0025] (3) Excellent construction applicability and appearance effect: The pressure-sensitive adhesive has appropriate initial adhesion (initial adhesion) and wettability, making it easy to slide and position during the film pasting process, with smooth air exhaust, greatly improving the construction efficiency and success rate. Once compacted, the adhesion rapidly increases to the final state. The adhesive layer can form good wetting with the TPU substrate and the paint surface, and finally present a crystal clear "invisible" effect without orange peel and bubbles, perfectly showing the original car paint surface texture.

[0026] (4) Simple process, easy to industrialize: The preparation method of the present application has clear process flow and easy-to-control process parameters, and has no special requirements for production equipment, with excellent repeatability and stability, which is very suitable for large-scale industrial production, and can meet the growing demand for high-performance pressure-sensitive adhesive in the high-end car cover market.

[0027] In summary, through innovative component design and preparation process, the present application successfully solves the long-standing contradiction between "high adhesion" and "anti-residue" in the TPU car cover film field, provides an acrylate pressure-sensitive adhesive product with comprehensive performance superior to existing technology, provides core material support for the development of high-end paint protection film, and has very high market application value.

[0028] Embodiment Embodiment 1 The acrylic ester pressure sensitive adhesive for TPU car film includes the following raw materials by weight: 60 parts of soft monomer, 30 parts of hard monomer, 7 parts of functional monomer, 0.3 parts of initiator, 0.3 parts of crosslinking agent, and 150 parts of organic solvent.

[0029] The soft monomer is isooctyl acrylate, the hard monomer is methyl acrylate, and the functional monomer is acrylic acid (6.7 parts) and glycidyl methacrylate (0.3 parts). The initiator is azobisisobutyronitrile. The organic solvent is ethyl acetate and isopropyl alcohol (30 parts). The composite crosslinking agent is a metal chelate.

[0030] The preparation method of the acrylic ester pressure sensitive adhesive comprises the following steps: Step 1: mix the soft monomer, hard monomer, and acrylic acid (6.7 parts) into a mixture, divide the mixture into a portion a (80%) and a portion b (20%) in a certain mass ratio, add glycidyl methacrylate (0.3 parts), isopropyl alcohol (30 parts), ethyl acetate, and an initiator to portion a and stir in a reaction kettle, and mix and stir the organic solvent and the initiator in portion b and place them in a high-position dropping tank; Step 2: then pass in nitrogen, continue to heat, and stop heating when the reaction kettle is in a state of explosive polymerization (under reflux temperature); Step 3: after waiting for fifteen minutes for the reaction temperature to stabilize, start uniform dropping of the high-position dropping tank and complete the dropping within 120 minutes, then perform heat preservation for a certain period of time, then add the mixed solution of the initiator and the organic solvent, perform uniform dropping and complete the dropping within 30 minutes, and then continue heat preservation for 4 hours; Step 4: add the organic solvent, reduce the temperature, then add the composite crosslinking agent, and finally stir to obtain the acrylic ester pressure sensitive adhesive.

[0031] The mass of the organic solvent added to portion a in step 1 is 60%, the masses of the organic solvent and the initiator added to the high-position tank in portion b are 30% and 60% respectively, the masses of the organic solvent and the initiator in step 3 are 10% and 40% respectively, the mass of the organic solvent in step 4 is 10%, and the temperature reduction refers to reduction to 45°C.

[0032] The overall stirring speed is 110 r / min.

[0033] The composite crosslinking agent is a metal chelate.

[0034] The use method of the acrylic ester pressure sensitive adhesive is as follows: coat the pressure sensitive adhesive on a PET release film, dry, then transfer to a TPU base film by lamination, place in an oven for curing, and then obtain the acrylic ester pressure sensitive adhesive tape.

[0035] The thickness of the coating on the PET release film is 15 μm, the thickness of the TPU base film is 50 μm, and the temperature and time of the curing are 60 °C and 48 h, respectively.

[0036] Example 2 The acrylic pressure-sensitive adhesive for the TPU car cover film includes the following raw materials by weight: 60 parts of soft monomer, 30 parts of hard monomer, 7 parts of functional monomer, 0.3 parts of initiator, 0.3 parts of crosslinking agent, and 150 parts of organic solvent.

[0037] The soft monomer is isooctyl acrylate, the hard monomer is methyl acrylate, and the functional monomer is acrylic acid (6.7 parts) and glycidyl methacrylate (0.3 parts). The initiator is azobisisobutyronitrile. The organic solvent is ethyl acetate and isopropyl alcohol (30 parts). The composite crosslinking agent is a metal chelate.

[0038] The preparation method of the acrylic pressure-sensitive adhesive comprises the following steps: Step 1: mix the soft monomer, the hard monomer, and acrylic acid (6.7 parts) into a mixture, divide the mixture into a part a (80%) and a part b (20%) in a certain mass ratio, add isopropyl alcohol (30 parts), ethyl acetate, and the initiator to part a and stir in a reaction kettle, add glycidyl methacrylate (0.3 parts), organic solvent, and the initiator to part b, mix, and place in a high-position dropping tank; Step 2: then pass nitrogen, continue to heat, and stop heating when the reaction kettle is in a state of explosive polymerization (under reflux temperature); Step 3: after waiting for fifteen minutes for the reaction temperature to stabilize, start uniform dropping of the high-position dropping tank and complete the dropping within 120 minutes, then perform heat preservation for a certain time, then add the mixture of the initiator and the organic solvent, perform uniform dropping within 30 minutes, and continue heat preservation for 4 h; Step 4: add the organic solvent, reduce the temperature, then add the composite crosslinking agent, and finally stir to obtain the acrylic pressure-sensitive adhesive.

[0039] Further, the mass of the organic solvent added to part a in step 1 is 60%, the masses of the organic solvent and the initiator added to the high-position tank in part b are 30% and 60% respectively, the masses of the organic solvent and the initiator in step 3 are 10% and 40% respectively, the mass of the organic solvent in step 4 is 10%, and the temperature reduction refers to reduction to 45 °C.

[0040] The total stirring speed is 110 r / min.

[0041] The composite crosslinking agent is a metal chelate.

[0042] The acrylic ester pressure sensitive adhesive is prepared by the following steps: mixing the soft monomer, the hard monomer, and the acrylic acid (6.7 parts) into a mixture, adding the glycidyl methacrylate (0.3 parts), the ethyl acetate, and the initiator to the a part (80%) of the mixture, adding the isopropyl alcohol (30 parts), the ethyl acetate, and the initiator to the b part (20%) of the mixture, and placing the b part in a high-position dropping tank, then passing nitrogen, continuing to heat, stopping heating when the reaction kettle is in the explosive polymerization state (at the reflux temperature), waiting for fifteen minutes after the reaction temperature is stable, starting uniform dropping of the high-position dropping tank and completing dropping within 120 minutes, then adding the mixture of the initiator and the organic solvent, uniform dropping and completing dropping within 30 minutes, continuing to heat for 4 hours, adding the organic solvent, cooling, adding the composite crosslinking agent, and finally stirring to obtain the acrylic ester pressure sensitive adhesive.

[0043] The thickness of the acrylic ester pressure sensitive adhesive coated on the PET release film is 15 μm, the thickness of the acrylic ester pressure sensitive adhesive on the TPU base film is 50 μm, and the temperature and time of the curing are 60 °C and 48 hours respectively.

[0044] Example 3 The acrylic ester pressure sensitive adhesive for the TPU car film includes the following raw materials by weight: 60 parts of the soft monomer, 30 parts of the hard monomer, 7 parts of the functional monomer, 0.3 parts of the initiator, 0.3 parts of the crosslinking agent, and 150 parts of the organic solvent.

[0045] The soft monomer is isooctyl acrylate, the hard monomer is methyl acrylate, and the functional monomer is acrylic acid (6.7 parts) and glycidyl methacrylate (0.3 parts). The initiator is azobis isobutyronitrile. The organic solvent is ethyl acetate and isopropyl alcohol (30 parts). The composite crosslinking agent is a metal chelate.

[0046] The preparation method of the acrylic ester pressure sensitive adhesive comprises the following steps: Step 1: mixing the soft monomer, the hard monomer, and the acrylic acid (6.7 parts) into a mixture, adding the glycidyl methacrylate (0.3 parts), the ethyl acetate, and the initiator to the a part (80%) of the mixture, adding the isopropyl alcohol (30 parts), the ethyl acetate, and the initiator to the b part (20%) of the mixture, and placing the b part in a high-position dropping tank, then passing nitrogen, continuing to heat, stopping heating when the reaction kettle is in the explosive polymerization state (at the reflux temperature), waiting for fifteen minutes after the reaction temperature is stable, starting uniform dropping of the high-position dropping tank and completing dropping within 120 minutes, then adding the mixture of the initiator and the organic solvent, uniform dropping and completing dropping within 30 minutes, continuing to heat for 4 hours, adding the organic solvent, cooling, adding the composite crosslinking agent, and finally stirring to obtain the acrylic ester pressure sensitive adhesive. Step 2: then passing nitrogen, continuing to heat, stopping heating when the reaction kettle is in the explosive polymerization state (at the reflux temperature); Step 3: waiting for fifteen minutes after the reaction temperature is stable, starting uniform dropping of the high-position dropping tank and completing dropping within 120 minutes, then adding the mixture of the initiator and the organic solvent, uniform dropping and completing dropping within 30 minutes, continuing to heat for 4 hours, adding the organic solvent, cooling, adding the composite crosslinking agent, and finally stirring to obtain the acrylic ester pressure sensitive adhesive. Step 4: adding the organic solvent, cooling, adding the composite crosslinking agent, and finally stirring to obtain the acrylic ester pressure sensitive adhesive.

[0047] Further, the mass of the organic solvent added to the a part in Step 1 is 60%, the mass of the organic solvent and the initiator added to the b part in the high-position tank is 30% and 60% respectively, the mass of the organic solvent and the initiator in Step 3 is 10% and 40% respectively, the mass of the organic solvent in Step 4 is 10%, and the cooling refers to cooling to 45 °C.

[0048] The total stirring speed is 110 r / min.

[0049] The complex crosslinking agent is a metal chelate.

[0050] The acrylic ester pressure sensitive adhesive is prepared by the following steps: step 1, mixing soft monomer, hard monomer and acrylic acid into a mixture, and dividing the mixture into a part a (80%) and a part b (20%) in a certain mass ratio; step 2, adding isopropyl alcohol (30 parts), ethyl acetate and initiator into the part a and stirring in a reaction kettle, and adding organic solvent, stirring and initiator into the part b and mixing and placing in a high-position dropping tank; step 3, then passing nitrogen, continuing to heat, and stopping heating when the reaction kettle is in a state of explosive polymerization (at a reflux temperature); step 4, waiting for fifteen minutes after the reaction temperature is stable, starting uniform dropping of the high-position dropping tank and completing dropping within 120 minutes, then performing heat preservation for a certain time, adding a mixed solution of initiator and organic solvent, uniform dropping and completing dropping within 30 minutes, and continuing heat preservation for 4 hours; step 5, adding organic solvent, cooling, adding a complex crosslinking agent, and finally stirring to obtain the acrylic ester pressure sensitive adhesive.

[0051] The thickness of the acrylic ester pressure sensitive adhesive coated on the PET release film is 15 μm, and the thickness of the acrylic ester pressure sensitive adhesive on the TPU base film is 50 μm, respectively, and the temperature and time of the curing are 60 ℃ and 48 h, respectively.

[0052] Comparative Example 1 The acrylic ester pressure sensitive adhesive for the TPU car film includes the following raw materials in parts by weight: soft monomer 60 parts, hard monomer 30 parts, functional monomer 6.7 parts, initiator 0.3 parts, crosslinking agent 0.3 parts, and organic solvent 150 parts.

[0053] The soft monomer is isooctyl acrylate, the hard monomer is methyl acrylate, the functional monomer is acrylic acid, the initiator is azobisisobutyronitrile, and the organic solvent is ethyl acetate and isopropyl alcohol (30 parts). The complex crosslinking agent is a metal chelate.

[0054] The preparation method of the acrylic ester pressure sensitive adhesive comprises the following steps: Step 1, mixing soft monomer, hard monomer and acrylic acid into a mixture, and dividing the mixture into a part a (80%) and a part b (20%) in a certain mass ratio; adding isopropyl alcohol (30 parts), ethyl acetate and initiator into the part a and stirring in a reaction kettle, and adding organic solvent, stirring and initiator into the part b and mixing and placing in a high-position dropping tank; Step 2, then passing nitrogen, continuing to heat, and stopping heating when the reaction kettle is in a state of explosive polymerization (at a reflux temperature); Step 3, waiting for fifteen minutes after the reaction temperature is stable, starting uniform dropping of the high-position dropping tank and completing dropping within 120 minutes, then performing heat preservation for a certain time, adding a mixed solution of initiator and organic solvent, uniform dropping and completing dropping within 30 minutes, and continuing heat preservation for 4 hours; Step 4, adding organic solvent, cooling, adding a complex crosslinking agent, and finally stirring to obtain the acrylic ester pressure sensitive adhesive.

[0055] The mass of the organic solvent added in part a of step 1 is 60%, the mass of the organic solvent and initiator added in the high tank in part b is 30% and 60%; the mass of the organic solvent and initiator in step 3 is 10% and 40% respectively, the mass of the organic solvent in step 4 is 10%, and the cooling refers to cooling to 45℃.

[0056] The total stirring speed is 110 r / min.

[0057] The composite crosslinking agent is a metal chelate.

[0058] The acrylic pressure-sensitive adhesive is prepared by the following steps:

[0059] The thickness of the PET release film is 15 μm, and the thickness of the TPU base film is 50 μm respectively, and the temperature and time of the curing are 60℃ and 48 h respectively.

[0060] Comparative Example 2: The acrylic pressure-sensitive adhesive for the TPU car film includes the following raw materials by weight: soft monomer 60 parts, hard monomer 30 parts, functional monomer 7 parts, initiator 0.3 parts, crosslinking agent 0.3 parts, and organic solvent 150 parts.

[0061] The soft monomer is isooctyl acrylate, the hard monomer is methyl acrylate, and the functional monomer is acrylic acid (6.7 parts) and glycidyl methacrylate (0.3 parts). The initiator is azobisisobutyronitrile. The organic solvent is ethyl acetate and isopropyl alcohol (30 parts). The composite crosslinking agent is a metal chelate.

[0062] The preparation method of the acrylic pressure-sensitive adhesive comprises the following steps: Step 1: mix the soft monomer, hard monomer and acrylic acid (6.7 parts) into a mixture, divide the mixture into part a (80%) and part b (20%) in a certain mass ratio, add glycidyl methacrylate (0.3 parts), ethyl acetate and initiator into the reaction kettle and stir, and add organic solvent into part b, mix and place in the high dropping tank; Step 2: then pass nitrogen, continue to heat, and stop heating when the reaction kettle reaches the explosive polymerization state (reflux temperature); Step 3: after waiting for 15 minutes for the reaction temperature to stabilize, start uniform dropping of the high dropping tank and complete the dropping within 120 minutes, then heat for a certain time, then add the mixed solution of initiator and organic solvent, drop uniformly and complete the dropping within 30 minutes, and continue to heat for 4 h. Step 4: add organic solvent, cool down, then add composite crosslinking agent, and finally stir to obtain the acrylate pressure-sensitive adhesive.

[0063] The mass of the organic solvent added in part a of step 1 is 60%, the mass of the organic solvent and initiator added in part b of step 1 is 30% and 60% respectively; the mass of the organic solvent and initiator in step 3 is 10% and 40% respectively, the mass of the organic solvent in step 4 is 10%, and the cooling down refers to cooling down to 45℃.

[0064] The total stirring speed is 110 r / min.

[0065] The composite crosslinking agent is a metal chelate.

[0066] The acrylate pressure-sensitive adhesive is used as follows: the pressure-sensitive adhesive is coated on a PET release film, dried, then transferred to a TPU base film by lamination, and placed in an oven for curing to obtain an acrylate pressure-sensitive adhesive tape.

[0067] The thickness of the coating on the PET release film is 15 μm, the thickness on the TPU base film is 50 μm respectively, and the curing temperature and time are 60℃ and 48 h respectively.

[0068] Comparative Example 3: The acrylate pressure-sensitive adhesive for the super-high peel strength acrylate pressure-sensitive adhesive for TPU car film comprises the following raw materials by weight: soft monomer 60 parts, hard monomer 30 parts, functional monomer 7 parts, initiator 0.3 parts, crosslinking agent 0.3 parts, and organic solvent 150 parts.

[0069] The soft monomer is isooctyl acrylate, the hard monomer is methyl acrylate, the functional monomer is acrylic acid (6.7 parts) and glycidyl methacrylate (0.3 parts), the initiator is azobisisobutyronitrile, the organic solvent is ethyl acetate and isopropyl alcohol (30 parts), and the composite crosslinking agent is a metal chelate.

[0070] The preparation method of the acrylate pressure-sensitive adhesive comprises the following steps: Step 1: mix the soft monomer and hard monomer to obtain a mixture, divide the mixture into a part a (80%) and a part b (20%) in a certain mass ratio, add acrylic acid (6.7 parts), glycidyl methacrylate (0.3 parts), isopropyl alcohol (30 parts), ethyl acetate, and initiator to part a in a reaction kettle and stir, and add organic solvent to part b, stir, mix with the initiator, and place in a high-level dropping tank; Step 2: then pass nitrogen gas, continue to heat, and stop heating when the reaction kettle reaches the state of explosive polymerization (reflux temperature); Step 3: After waiting for 15 minutes until the temperature is stable, start the uniform titration of the high-position dropping tank and complete the dropping within 120 minutes, then keep the temperature for a certain time, and then add the mixed solution of initiator and organic solvent, and complete the dropping within 30 minutes, and continue to keep the temperature for 4 hours; Step 4: Add organic solvent, cool down, then add composite crosslinking agent, and finally stir to obtain the acrylate pressure-sensitive adhesive.

[0071] The mass of the organic solvent added in part a of step 1 is 60%, the mass of the organic solvent and initiator added in the high-position tank of part b is 30% and 60%, respectively; the mass of the organic solvent and initiator in step 3 is 10% and 40%, respectively, the mass of the organic solvent in step 4 is 10%, and the cooling down refers to cooling down to 45℃.

[0072] The total stirring speed is 110 r / min.

[0073] The composite crosslinking agent is a metal chelate.

[0074] The use method of the acrylate pressure-sensitive adhesive is as follows: the pressure-sensitive adhesive is coated on a PET release film, dried, then transferred to a TPU base film by lamination, and placed in an oven for curing, thereby obtaining an acrylate pressure-sensitive adhesive tape.

[0075] The thickness of the coating on the PET release film is 15 μm, and the thickness on the TPU base film is 50 μm, respectively, and the curing temperature and time are 60℃ and 48h, respectively.

[0076] Comparative Example 4: The acrylate pressure-sensitive adhesive for the TPU car film includes the following raw materials by weight: soft monomer 60 parts, hard monomer 30 parts, functional monomer 7 parts, initiator 0.3 parts, crosslinking agent 0.3 parts, and organic solvent 150 parts.

[0077] The soft monomer is isooctyl acrylate, the hard monomer is methyl acrylate, the functional monomer is acrylic acid (6.7 parts) and glycidyl methacrylate (0.3 parts). The initiator is azobis isobutyronitrile. The organic solvent is ethyl acetate and isopropyl alcohol (30 parts). The composite crosslinking agent is a metal chelate.

[0078] The preparation method of the acrylate pressure-sensitive adhesive comprises the following steps: Step 1: the soft monomer, hard monomer is mixed into a mixture, the mixture is divided into a part (80%) and a part (20%) of a certain mass ratio, the a part is filled with glycidyl methacrylate (0.3 parts), isopropyl alcohol (30 parts), ethyl acetate and initiator is stirred in the reaction kettle, the b part is added with acrylic acid (6.7 parts), ethyl acetate is stirred and mixed with initiator and placed in the high level dropping funnel; Step 2: then nitrogen is introduced, the temperature continues to rise, and the reaction kettle is stopped heating when the explosive polymerization state (reflux temperature) is reached; Step 3: after the reaction temperature is stable for 15 minutes, the high level dropping funnel starts to drop at a constant speed and is added within 120 minutes, then the temperature is kept for a certain time, and then the mixed solution of initiator and organic solvent is added, which is dropped at a constant speed and within 30 minutes, and then the temperature is kept for 4 hours; Step 4: add organic solvent, cool down, add composite crosslinking agent, and finally stir to obtain the acrylic ester pressure sensitive adhesive.

[0079] The mass of the organic solvent added in the a part of step 1 is 60%, the mass of the organic solvent and initiator added in the b part of the high level tank is 30% and 60%; the mass of the organic solvent and initiator in step 3 is 10% and 40% respectively, the mass of the organic solvent in step 4 is 10%, and the cooling refers to cooling to 45℃.

[0080] The total stirring speed is 110 r / min.

[0081] The composite crosslinking agent is a metal chelate.

[0082] The use method of the acrylic ester pressure sensitive adhesive is as follows: the pressure sensitive adhesive is coated on the PET release film, dried, then transferred to the TPU base film, placed in the oven for curing, and the acrylic ester pressure sensitive adhesive tape is obtained.

[0083] The thickness of the coating on the PET release film is 15 μm, the thickness of the TPU base film is 50 μm respectively, and the temperature and time of the curing are 60℃ and 48h respectively.

[0084] Comparative example 5: The acrylic ester pressure sensitive adhesive for TPU car film includes the following raw materials by weight: soft monomer 60 parts, hard monomer 30 parts, functional monomer 7 parts, initiator 0.3 parts, crosslinking agent 0.3 parts, organic solvent 150 parts.

[0085] The soft monomer is isooctyl acrylate, the hard monomer is methyl acrylate, the functional monomer is acrylic acid (6.7 parts) and glycidyl methacrylate (0.3 parts). The initiator is azobisisobutyronitrile. The organic solvent is ethyl acetate and isopropanol (30 parts). The composite crosslinking agent is a metal chelate.

[0086] The preparation method of the acrylic ester pressure-sensitive adhesive comprises the following steps: Step 1: mix the soft monomer, the hard monomer, acrylic acid (6.7 parts) and glycidyl methacrylate (0.3 parts) into a mixture, divide the mixture into a part a (80%) and a part b (20%) in a certain mass ratio, add isopropanol (30 parts), ethyl acetate and the initiator to the part a and stir in a reaction kettle, mix and stir the part b with the organic solvent and the initiator and place in a high-position dropping tank; Step 2: then pass in nitrogen, continue to heat, and stop heating when the reaction kettle is in a state of explosive polymerization (under reflux temperature); Step 3: after waiting for 15 minutes for the reaction temperature to be stable, start uniform dropping of the high-position dropping tank and complete the dropping within 120 minutes, then perform heat preservation for a certain time, then add the mixed liquid of the initiator and the organic solvent, perform uniform dropping and complete the dropping within 30 minutes, and continue to heat preserve for 4 hours; Step 4: add the organic solvent, cool down, add the composite crosslinking agent, and finally stir to obtain the acrylic ester pressure-sensitive adhesive.

[0087] The mass of the organic solvent added in the part a in step 1 is 60%, the mass of the organic solvent and the initiator added in the high-position tank in the part b is 30% and 60%, the mass of the organic solvent and the initiator in step 3 is 10% and 40%, the mass of the organic solvent in step 4 is 10%, and the cooling down refers to cooling down to 45℃.

[0088] The total stirring speed is 110 r / min.

[0089] The composite crosslinking agent is a metal chelate.

[0090] The use method of the acrylic ester pressure-sensitive adhesive is as follows: coat the pressure-sensitive adhesive on a PET release film, dry, then transfer to a TPU base film, place in an oven for curing, and then the acrylic ester pressure-sensitive adhesive tape is obtained.

[0091] The thickness of the coating on the PET release film is 15 μm, the thickness on the TPU base film is 50 μm respectively, and the temperature and time of the curing are 60℃ and 48 hours respectively.

[0092] Performance test: The pressure-sensitive adhesives prepared in examples 1-3 and comparative examples 1-5 are used as samples and the following tests are performed respectively: Viscosity test: The viscosity of the sample was measured at 25°C using a digital viscometer according to GB / T2794-1995 standard.

[0093] Solid content test: The solid content of the adhesive, also known as the non-volatile content, is the mass percentage of non-volatile substances in the adhesive under specified test conditions. In this invention, examples 1-3 and comparative examples 1-5 all adjust the theoretical solid content to 32.5%. First, weigh the clean and dry surface dish as m0, then add a certain amount of pressure-sensitive adhesive to the surface dish with the mass after peeling as m1, and place it in a programmable high-temperature oven at 150°C for 25 minutes (with drum air). Record the mass as m2. The same sample is tested and calculated 3 times according to the above operation steps, and the average value is taken.

[0094] Solid content: G = (m2-m0) / m1; Where G is the solid content (%); m0 is the mass of the surface dish (g); m1 is the mass of the sample after peeling without drying (g); m2 is the mass of the surface dish and sample after drying (g).

[0095] 180° peel strength test: The test was performed using a tensile test according to GB / T2792-2014 standard.

[0096] Initial adhesion test: According to GB / T4852-2002 standard, the sample was tested with a steel ball. The greater the steel strength, the better the initial adhesion.

[0097] Holding adhesion test: The test sample was prepared according to GB / T4851-2014 standard, and the test sample was placed in a "double 85 high temperature and high humidity aging condition", and a 1kg standard weight was hung for testing, and the holding time of each sample was recorded.

[0098] High temperature accelerated test: The original coated product base film was adhered to a stainless steel plate according to GB / T2792-2014 standard, and was placed in a 150°C oven for 70 minutes. It was not cooled in the oven and was directly torn off, which was called "hot tearing". It was taken out of the oven, cooled, and then torn off at room temperature, which was called "cold tearing". Whether there was residual glue on the stainless steel plate after "hot tearing" or "cold tearing" was observed.

[0099] Test results: The detailed test results are shown in Table 1.

[0100] Table 1: Comparison of basic properties of examples 1-3 and comparative examples 1-5, the details are as follows:

[0101] As shown in Table 1, Examples 1-3 have a viscosity suitable for direct coating and a high conversion rate, have an ultra-high peel force on the substrate, and at the same time, their tack retention time performance is also very outstanding.

[0102] Table 2: Comparison of high temperature accelerated test data of Examples 1-3 and Comparative Examples 1-5, details as follows:

[0103] As shown in Table 2, Examples 1-3 have excellent heat and cold tear resistance, the adhesive itself has very high cohesive strength and modulus, and when subjected to tear stress, the failure mode is a healthy balance between cohesive failure and interfacial adhesive failure, thus fundamentally eliminating the residue phenomenon when removed, achieving the ideal effect of "strongly adhered and cleanly torn".

[0104] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with a preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the present application, and any simple modification, equivalent replacement and improvement of the above embodiments within the scope of the technical solution of the present application, in accordance with the technical essence of the present application, within the spirit and principles of the present application, are all within the protection scope of the present application.

Claims

1. An ultra-high peel strength acrylate pressure sensitive adhesive for TPU car wrap films, characterized in that, The mass fraction of each component in the pressure sensitive adhesive is: 60-80 parts of soft monomer, 30-50 parts of hard monomer, 5-20 parts of functional monomer, 0.1-0.5 parts of initiator, 0.1-0.5 parts of crosslinking agent, 50-300 parts of organic solvent.

2. The super high peel strength acrylate pressure sensitive adhesive for TPU car wrap film according to claim 1, characterized in that, The soft monomer is any one or several of ethyl acrylate, butyl acrylate, isooctyl acrylate, lauryl methacrylate; The hard monomer is any one or several of methyl acrylate, vinyl acetate, tert-butyl acrylate, isobornyl methacrylate.

3. The super high peel acrylate pressure sensitive adhesive for TPU car film according to claim 1, characterized in that, The functional monomer is any one or several of acrylic acid, isooctyl acrylate, hydroxybutyl acrylate, hydroxyethyl acrylate, glycidyl methacrylate.

4. The super high peel acrylate pressure sensitive adhesive for TPU car film according to claim 1, characterized in that, The initiator is any one or several of dibenzoyl peroxide, azobis isobutyronitrile, azobis isoamyl nitrile, azobis isoheptyl nitrile; The organic solvent is any one or several of ethyl acetate, cyclohexane, toluene, isopropyl alcohol.

5. The super high peel acrylate pressure sensitive adhesive for TPU car film according to claim 1, characterized in that, The crosslinking agent is any one or several of metal chelate, amino resin, isocyanate, aziridine and epoxy.

6. A method for preparing super high peel strength acrylate pressure sensitive adhesive for TPU car wrap film, characterized in that, The specific steps include: Step 1, mix the soft monomer, hard monomer and functional monomer into a mixture, divide the mixture into a and b parts, add organic solvent to a part and stir, and add initiator to b part and stir in the reaction kettle, mix and place in a high-level dropping tank; wherein a part is 60%-80%, and b part is 40%-20%; Step 2, then introduce nitrogen, continue to heat, and stop heating when the reaction kettle reaches the explosive polymerization state; Step 3, after the reaction temperature stabilizes for 15 minutes, start uniform dropping of the high-level dropping tank and complete the dropping within 120 minutes, then perform heat preservation, and then add the mixed solution of initiator and organic solvent, uniform dropping and complete the dropping within 30 minutes, and continue heat preservation for 4 hours; Step 4, add organic solvent, cool down, add composite crosslinking agent, and finally stir to obtain the acrylic pressure sensitive adhesive.

7. The method according to claim 6, wherein the method is characterized by, The mass of the organic solvent added to a part in step 1 is 60%, the mass of the organic solvent and initiator added to the high-level tank in b part is 30% and 60%, the mass of the organic solvent and initiator in step A3 is 10% and 40%, the mass of the organic solvent in step A4 is 10%, and the cooling down refers to cooling down to 45℃.

8. The method for preparing the super-high peel strength acrylate pressure-sensitive adhesive for TPU car film according to claim 6, characterized in that, The stirring speed in steps 1-4 is 110r / min, and the composite crosslinking agent is any one or several of metal chelate, amino resin, isocyanate, aziridine and epoxy.

9. The method according to claim 6, wherein the method is characterized by, The use method of the acrylic pressure sensitive adhesive is as follows: coat the pressure sensitive adhesive on a PET release film, dry, then transfer to a TPU base film or directly coat on a PET base film, place in an oven for curing, and then the acrylic pressure sensitive adhesive tape is obtained.

10. The method for preparing the super-high peel strength acrylate pressure-sensitive adhesive for TPU car film according to claim 6, characterized in that, The thickness of the coating on the PET release film is 15μm, the thickness on the TPU base film is 50μm, and the curing temperature and time are 60℃ and 48h respectively.

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