A high-adhesion biomass-based acrylic pressure-sensitive adhesive and pressure-sensitive tape, and their preparation method

Abstract

This invention provides a high-adhesion biomass-based acrylate pressure-sensitive adhesive and pressure-sensitive tape, as well as their preparation method. The biomass-based acrylate pressure-sensitive adhesive and pressure-sensitive tape are composed of the following raw materials by weight: 60-80 parts of biomass-based acrylate soft monomer, 10-20 parts of biomass-based acrylate hard monomer, 10-20 parts of functional monomer, 80-120 parts of ethyl acetate solvent, 0.3-0.7 parts of benzoyl peroxide initiator, 2-10 parts of tackifying resin, and 0.2-1 parts of crosslinking agent. The biomass-based acrylate pressure-sensitive adhesive obtained by this invention has the advantages of simple preparation process, strong adhesion, low toxicity, and good environmental performance, and has good application prospects in the pressure-sensitive adhesive industry.

Description

Technical Field

[0001] This invention belongs to the field of pressure-sensitive adhesive technology, specifically relating to a high-adhesion biomass-based acrylate pressure-sensitive adhesive and pressure-sensitive tape, and their preparation methods. Background Technology

[0002] Pressure-sensitive adhesives are self-adhesive adhesives that are sensitive to pressure. Due to their ease of use, rapid bonding, and residue-free peeling, they are widely used in food packaging, medical fields, electronics industry, construction, and automotive industries. Among them, acrylic pressure-sensitive adhesives are the most widely used type due to their simple composition, high transparency, and excellent weather resistance. Acrylic pressure-sensitive adhesives are mainly prepared by free radical polymerization of monomers containing unsaturated carbon-carbon double bonds under the action of a catalyst.

[0003] However, the preparation of traditional acrylic pressure-sensitive adhesives mainly relies on non-renewable petrochemical resources, which exacerbates the contradiction between the supply and demand of petrochemical resources in my country. Meanwhile, with increasing environmental awareness, people are placing higher demands on the environmental friendliness and sustainability of adhesives. The environmental pollution problems that may arise during the preparation and use of traditional acrylic pressure-sensitive adhesives also limit their application. Furthermore, although acrylic pressure-sensitive adhesives have many advantages, their tackiness is often not ideal, which also limits their application in situations where a long-term bond is required.

[0004] Therefore, the search for environmentally friendly acrylic pressure-sensitive adhesives that can reduce petroleum resource consumption and possess excellent tackiness is particularly important. In recent years, with the development and utilization of biomass resources, the preparation of high-performance pressure-sensitive adhesives using renewable biomass resources has attracted attention. Summary of the Invention

[0005] This invention addresses the problems of existing acrylate pressure-sensitive adhesives, which primarily rely on non-renewable petrochemical resources, exhibiting unsatisfactory tackiness and poor environmental performance. It proposes a method for preparing high-tack biomass-based acrylate pressure-sensitive adhesives and tapes using soft and hard monomers derived from biomass-based resources. The biomass-based acrylate pressure-sensitive adhesive not only possesses non-toxic, environmentally friendly, and biodegradable characteristics, but also, through the rational selection and ratio of soft and hard monomers, can be endowed with excellent tackiness, thereby meeting various application requirements.

[0006] The technical solution adopted in this invention is:

[0007] A high-tack biomass-based acrylate pressure-sensitive adhesive, comprising the following components by weight: 60-80 parts of biomass-based soft acrylate monomer, 10-20 parts of biomass-based hard acrylate monomer, 10-20 parts of functional monomer, 80-120 parts of solvent ethyl acetate, and 0.3-0.7 parts of initiator benzoyl peroxide.

[0008] The biomass-based acrylate soft monomers include any one or both of lauryl methacrylate and lauryl acrylate.

[0009] The biomass-based acrylate hard monomers include one or more of tetrahydrofurfuryl acrylate and tetrahydrofurfuryl methacrylate.

[0010] The functional monomers include any one or more of acrylic acid, itaconic acid, glycidyl acrylate, and hydroxypropyl methacrylate.

[0011] A high-adhesion biomass-based acrylate pressure-sensitive adhesive tape comprises the following components, in parts by weight: 200 parts of the biomass-based acrylate pressure-sensitive adhesive as described in claim 1, 2-10 parts of tackifying resin, and 0.2-1 parts of crosslinking agent.

[0012] The tackifying resin is rosin resin.

[0013] The crosslinking agent is aluminum acetylacetonate.

[0014] A method for preparing the above-mentioned high-adhesion biomass-based acrylate pressure-sensitive adhesive is characterized in that, by weight, 60-80 parts of ethyl acetate and 0.1-0.3 parts of initiator are added to a 500 mL three-necked flask, and the mixture is heated to 80°C while stirring. Then, 60-80 parts of biomass-based acrylate soft monomer are added, followed by the slow addition of 10-20 parts of biomass-based acrylate hard monomer, 0.2-0.4 parts of benzoyl peroxide, 10-20 parts of functional monomer, and 20-40 parts of ethyl acetate. After the addition is complete, the reaction is continued at 90°C for 3-5 h. After cooling, the biomass-based acrylate pressure-sensitive adhesive is obtained.

[0015] First, the biomass-based acrylate hard monomer, benzoyl peroxide, functional monomer and ethyl acetate are mixed evenly, and then slowly added dropwise to the reaction vessel over 80-100 minutes using a constant pressure dropping funnel.

[0016] A method for preparing the above-mentioned high-adhesion biomass-based acrylate pressure-sensitive adhesive tape is characterized in that, by weight, 2-10 parts of tackifying resin and 0.2-1 parts of crosslinking agent are added to 200 parts of biomass-based acrylate pressure-sensitive adhesive, stirred evenly, and after the bubbles in the adhesive solution basically disappear after 15-30 minutes, it is coated on a PET release film and heated in an oven at 90-110℃ for 2-3 hours to obtain the biomass-based acrylate pressure-sensitive adhesive tape.

[0017] Compared with existing technical solutions, the present invention has at least the following beneficial effects:

[0018] 1. Environmentally Friendly and Sustainable: Both the soft and hard monomers in this invention utilize acrylate monomers derived from renewable biomass resources, increasing the biomass carbon content of the adhesive and reducing the use of petrochemical raw materials. Therefore, the prepared biomass-based acrylate pressure-sensitive adhesive is non-toxic, environmentally friendly, and biodegradable, demonstrating outstanding environmental sustainability.

[0019] 2. High Holding Power: This invention utilizes biomass-based soft and hard monomers with unique chemical structures. By adjusting their types and amounts, and introducing functional monomers such as acrylic acid, itaconic acid, glycidyl acrylate, and hydroxypropyl methacrylate, these functional monomers not only participate in the polymerization reaction but also enhance the cohesive strength and adhesion properties of the pressure-sensitive adhesive through synergistic effects with other components. Therefore, the biomass-based acrylic pressure-sensitive adhesive prepared by this invention exhibits excellent holding power, maintaining a holding power of over 400 hours at room temperature.

[0020] 3. Mild Process Conditions: The biomass-based acrylate pressure-sensitive adhesive developed in this invention has mild preparation conditions and is less prone to residue formation. By adding solvents, initiators, and monomers in batches, the temperature and monomer concentration during the reaction process can be effectively controlled, promoting a stable and uniform reaction, thereby improving the quality and performance of the pressure-sensitive adhesive.

[0021] In summary, this invention provides a high-adhesion, environmentally friendly and sustainable biomass-based acrylic pressure-sensitive adhesive and pressure-sensitive tape, as well as a method for their preparation. It solves the problems of existing acrylic pressure-sensitive adhesives, which mainly rely on non-renewable petrochemical resources, have unsatisfactory adhesion, and poor environmental performance, and shows broad application prospects. Attached Figure Description

[0022] Figure 1 It is the molecular formula of lauryl methacrylate.

[0023] Figure 2 It is the molecular formula of tetrahydrofurfuryl methacrylate.

[0024] Figure 3 The molecular formula is isobornyl methacrylate.

[0025] Figure 4 This is the molecular formula for acrylic acid.

[0026] Figure 5 This is the molecular formula for butyl acrylate. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments. These embodiments are for illustrating the present invention and are not limited to the scope of the present invention, and also include any combination of the specific embodiments. The implementation conditions used in the embodiments can be further adjusted according to the specific experimental environment, and the implementation conditions not specified are generally the conditions in conventional experiments.

[0028] Example 1

[0029] Preparation of pressure-sensitive adhesive: By weight, 60 parts of ethyl acetate and 0.1 parts of benzoyl peroxide were added to a 500 mL three-necked round-bottom flask. While stirring, the temperature was raised to 80°C. Then, 60 parts of the soft monomer lauryl methacrylate were added at once. Then, 20 parts of the hard monomer tetrahydrofurfuryl methacrylate, 0.2 parts of benzoyl peroxide, 20 parts of acrylic acid and 40 parts of ethyl acetate were added dropwise over 100 min using a constant pressure dropping funnel. After the addition was completed, the reaction was continued at 90°C for 3 h. After cooling, the biomass-based acrylate pressure-sensitive adhesive was obtained.

[0030] Preparation of pressure-sensitive adhesive tape: Add 2 parts of rosin resin and 0.2 parts of aluminum acetylacetonate to 200 parts of biomass-based acrylate pressure-sensitive adhesive, stir evenly, and after 15 minutes when the bubbles in the adhesive solution basically disappear, coat it on PET release film, and bake at 90℃ for 3 hours to obtain biomass-based acrylate pressure-sensitive adhesive tape.

[0031] Example 2

[0032] Preparation of pressure-sensitive adhesive: By weight, 65 parts of ethyl acetate and 0.1 parts of benzoyl peroxide were added to a 500 mL three-necked round-bottom flask. While stirring, the temperature was raised to 80 °C. Then, 65 parts of the soft monomer lauryl methacrylate were added at once. Then, 17.5 parts of the hard monomer tetrahydrofurfuryl methacrylate, 0.3 parts of benzoyl peroxide, 17.5 parts of acrylic acid and 35 parts of ethyl acetate were added dropwise over 95 min using a constant pressure dropping funnel. After the addition was completed, the reaction was continued at 90 °C for 3.5 h. After cooling, the biomass-based acrylate pressure-sensitive adhesive was obtained.

[0033] Preparation of pressure-sensitive adhesive tape: Add 4 parts of rosin resin and 0.4 parts of aluminum acetylacetonate to 200 parts of biomass-based acrylate pressure-sensitive adhesive. After stirring evenly, wait for the bubbles in the adhesive to basically disappear after 20 minutes. Then coat it onto PET release film and bake it at 90℃ for 3 hours to obtain biomass-based acrylate pressure-sensitive adhesive tape.

[0034] Example 3

[0035] Preparation of pressure-sensitive adhesive: By weight, 70 parts of ethyl acetate and 0.2 parts of benzoyl peroxide were added to a 500 mL three-necked round-bottom flask. While stirring, the temperature was raised to 80°C. Then, 70 parts of the soft monomer lauryl methacrylate were added at once. Then, 15 parts of the hard monomer tetrahydrofurfuryl methacrylate, 0.3 parts of benzoyl peroxide, 15 parts of acrylic acid and 30 parts of ethyl acetate were added dropwise over 90 min using a constant pressure dropping funnel. After the addition was completed, the reaction was continued at 90°C for 4 h. After cooling, the biomass-based acrylate pressure-sensitive adhesive was obtained.

[0036] Preparation of pressure-sensitive adhesive tape: Add 6 parts of rosin resin and 0.6 parts of aluminum acetylacetonate to 200 parts of biomass-based acrylate pressure-sensitive adhesive. After stirring evenly, wait for the bubbles in the adhesive to basically disappear after 25 minutes. Then coat it onto PET release film and bake it at 100℃ for 2.5 hours to obtain biomass-based acrylate pressure-sensitive adhesive tape.

[0037] Example 4

[0038] Preparation of pressure-sensitive adhesive: By weight, 75 parts of ethyl acetate and 0.2 parts of benzoyl peroxide were added to a 500 mL three-necked round-bottom flask. While stirring, the temperature was raised to 80 °C. Then, 75 parts of the soft monomer lauryl methacrylate were added at once. Then, 12.5 parts of the hard monomer tetrahydrofurfuryl methacrylate, 0.4 parts of benzoyl peroxide, 12.5 parts of acrylic acid and 25 parts of ethyl acetate were added dropwise over 85 min using a constant pressure dropping funnel. After the addition was completed, the reaction was continued at 90 °C for 4.5 h. After cooling, the biomass-based acrylate pressure-sensitive adhesive was obtained.

[0039] Preparation of pressure-sensitive adhesive tape: Add 8 parts of rosin resin and 0.8 parts of aluminum acetylacetonate to 200 parts of biomass-based acrylate pressure-sensitive adhesive. After stirring evenly, wait for the bubbles in the adhesive to basically disappear after 25 minutes. Then coat it onto PET release film and bake it at 100℃ for 2.5 hours to obtain biomass-based acrylate pressure-sensitive adhesive tape.

[0040] Example 5

[0041] Preparation of pressure-sensitive adhesive: By weight, 80 parts of ethyl acetate and 0.3 parts of benzoyl peroxide were added to a 500 mL three-necked round-bottom flask. While stirring, the temperature was raised to 80°C. Then, 80 parts of the soft monomer lauryl methacrylate were added at once. Then, 10 parts of the hard monomer tetrahydrofurfuryl methacrylate, 0.4 parts of benzoyl peroxide, 10 parts of acrylic acid and 20 parts of ethyl acetate were added dropwise over 80 min using a constant pressure dropping funnel. After the addition was completed, the reaction was continued at 90°C for 5 h. After cooling, the biomass-based acrylate pressure-sensitive adhesive was obtained.

[0042] Preparation of pressure-sensitive adhesive tape: Add 10 parts of rosin resin and 1 part of aluminum acetylacetonate to 200 parts of biomass-based acrylate pressure-sensitive adhesive, stir it evenly, and after the bubbles in the adhesive solution basically disappear after 30 minutes, coat it on PET release film, and bake it at 110℃ for 2 hours to obtain biomass-based acrylate pressure-sensitive adhesive tape.

[0043] Comparative Example 1

[0044] The difference between this comparative example and Example 1 is that the functional monomer acrylic acid is not added, while the other raw materials and processes are the same as in Example 1.

[0045] Comparative Example 2

[0046] The difference between this comparative example and Example 1 is that the hard monomer tetrahydrofurfuryl methacrylate is added all at once, while the soft monomer lauryl methacrylate is added slowly dropwise together with the initiator and functional monomer. All other raw materials and processes are the same as in Example 1.

[0047] Comparative Example 3

[0048] The difference between this comparative example and Example 1 is that the soft monomer lauryl methacrylate is replaced with butyl acrylate, while the other raw materials and processes are the same as in Example 1.

[0049] Comparative Example 4

[0050] The difference between this comparative example and Example 1 is that the hard monomer tetrahydrofurfuryl methacrylate is replaced with isobornyl methacrylate, while the other raw materials and processes are the same as in Example 1.

[0051] Comparative Example 5

[0052] The difference between this comparative example and Example 1 is that 100 parts of the solvent ethyl acetate were added at once, while the other raw materials and processes were the same as in Example 1.

[0053] Comparative Example 6

[0054] The difference between this comparative example and Example 1 is that 0.3 parts of the initiator benzoyl peroxide were added all at once, while the other raw materials and processes were the same as in Example 1.

[0055] Comparative Example 7

[0056] The difference between this comparative example and Example 1 is that the monomer, solvent and initiator are all mixed together at once for preparation, instead of being added in batches according to the proportion. The other raw materials and processes are the same as in Example 1.

[0057] Performance testing

[0058] Initial tack, holding tack and 180° peel strength tests: conducted in accordance with GB / T 4852-2002, GB / T 4851-1998 and GB / T 2792-1998 standards.

[0059] The solid content was determined by the following method: Weigh 1-2 g of the adhesive sample, place it in a drying oven at 120℃ and dry it at a constant temperature for three hours, and calculate its solid content after cooling.

[0060] The results are shown in the table below:

[0061]

[0062] As can be seen from the data in the table above, the biomass-based acrylic pressure-sensitive adhesives prepared by the method described in this invention in Examples 1-5 exhibit better holding power compared to the comparative examples, with holding power exceeding 400 h in all cases. Furthermore, both the soft and hard monomers used are from biomass resources; therefore, the prepared acrylic pressure-sensitive adhesives have a high biomass carbon content, conforming to the concept of green environmental protection. Simultaneously, the preparation conditions are mild. Examples 1-5, by employing biomass-based soft and hard monomers with unique molecular structures and introducing functional monomers, obtained pressure-sensitive adhesives with outstanding holding power through free radical copolymerization.

[0063] The experimental results of Comparative Example 1 and Example 1 show that without the addition of the functional monomer acrylic acid, the initial tack and holding power of the pressure-sensitive adhesive prepared in Comparative Example 1 are reduced. This is mainly because the carboxyl groups contained in acrylic acid can form hydrogen bonds or other forces with the polar groups on the bonded surface, thereby improving the bonding performance. It can also cross-link with other monomers to improve the cohesive strength of the pressure-sensitive adhesive, thereby improving the initial tack and holding power of the pressure-sensitive adhesive.

[0064] The experimental results of Comparative Example 2 and Example 1 show that the pressure-sensitive adhesive prepared by adding the hard monomer all at once and then slowly adding the soft monomer has better initial tack but poor holding power. This is mainly because when the hard monomer is added all at once, it is easy to form harder polymer chains in the early stage of the reaction, while the slowly added soft monomer continues to react and generates a softer cross-linked network that wraps around the surface of the hard monomer, making the pressure-sensitive adhesive softer, improving the initial tack but decreasing the holding power.

[0065] The experimental results of Comparative Example 3 and Example 1 show that replacing lauryl methacrylate with butyl acrylate results in a higher proportion of flexible units in the molecular structure of lauryl methacrylate compared to butyl acrylate. The longer-chain flexible units can improve the wettability of the pressure-sensitive adhesive to the substrate, thereby enhancing the adhesion. This results in the pressure-sensitive adhesive prepared in Comparative Example 1 having reduced initial tack and holding power.

[0066] A comparison of the experimental results of Comparative Example 4 and Example 1 shows that replacing tetrahydrofurfuryl methacrylate with isobornyl methacrylate reduces the tack of the pressure-sensitive adhesive prepared in Comparative Example 3. This is mainly because, compared with isobornyl methacrylate, the tetrahydrofuran group contained in tetrahydrofurfuryl methacrylate has strong polarity, which can improve the adhesion of the pressure-sensitive adhesive to various substrates and thus improve the tack of the pressure-sensitive adhesive.

[0067] The experimental results of Comparative Example 5 and Example 1 show that adding ethyl acetate solvent in batches can help promote the uniform mixing of soft monomers, hard monomers and functional monomers in the system and the free radical polymerization reaction by controlling the concentration of each monomer in the reaction. As a result, the pressure-sensitive adhesive prepared in the comparative example has lower tack than that in Example 1.

[0068] The experimental results of Comparative Example 6 and Example 1 show that when all the initiators are added in one batch, the concentration of the initiator is too high, which will quickly induce free radical polymerization between monomers. The excessively fast polymerization reaction results in insufficient reaction, which ultimately leads to a significant decrease in the tack and initial tack of the pressure-sensitive adhesive.

[0069] The experimental results of Comparative Example 7 and Example 1 show that when the soft monomer, hard monomer, solvent and initiator are directly mixed and reacted at one time, the initiator and monomer concentrations are too high, the reaction is violent, the mixed system is unstable, and finally gels, making it unsuitable for preparing acrylate pressure-sensitive tape.

[0070] The performance test results of the examples and comparative examples show that the biomass-based acrylic pressure-sensitive adhesive prepared by the method described in this invention exhibits excellent tackiness. The tackiness of the examples all exceeds 400 hours, which is significantly better than that of the comparative examples. Furthermore, the pressure-sensitive adhesive of this invention does not leave any residue during use and has a high solids content.

[0071] The beneficial effects of the technology of this invention are mainly reflected in the following aspects: First, by using biomass-based resources to replace traditional petrochemical resources, the environmental friendliness and sustainability of adhesives are significantly improved; second, by optimizing the ratio of soft and hard monomers with unique structures and introducing functional monomers, the tackiness of pressure-sensitive adhesives is greatly improved, meeting the application scenarios that require long-term bonding performance; finally, the preparation process conditions are mild and easy to control, ensuring the stability and consistency of product quality.

[0072] In practical applications, the biomass-based acrylic pressure-sensitive adhesive of the present invention can be used in many fields such as food packaging, medical, electronics, construction and automobiles. Due to its environmental protection characteristics and excellent bonding performance, it can meet the growing market demand for high-performance and environmentally friendly adhesives, showing broad market application prospects.

[0073] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-adhesion biomass-based acrylic pressure-sensitive adhesive, characterized in that: The biomass-based acrylate pressure-sensitive adhesive comprises the following components by weight: 60-80 parts of biomass-based acrylate soft monomer, 10-20 parts of biomass-based acrylate hard monomer, 10-20 parts of functional monomer, 80-120 parts of solvent ethyl acetate, and 0.3-0.7 parts of initiator benzoyl peroxide. The biomass-based acrylate hard monomers include one or more of tetrahydrofurfuryl acrylate and tetrahydrofurfuryl methacrylate. The preparation method of the high-adhesion biomass-based acrylate pressure-sensitive adhesive is as follows: 60-80 parts by mass of ethyl acetate and 0.1-0.3 parts by mass of initiator are added to a 500 mL three-necked flask, and the temperature is raised to 80°C while stirring. Then, 60-80 parts of biomass-based acrylate soft monomer are added, followed by the slow addition of 10-20 parts of biomass-based acrylate hard monomer, 0.2-0.4 parts of benzoyl peroxide, 10-20 parts of functional monomer, and 20-40 parts of ethyl acetate. After the addition is complete, the mixture is uniformly mixed and slowly added to the reaction vessel over 80-100 min using a constant pressure dropping funnel. The reaction is carried out at 90°C for 3-5 h, and the biomass-based acrylate pressure-sensitive adhesive is obtained after cooling. The biomass-based acrylate soft monomers include any one or both of lauryl methacrylate and lauryl acrylate.

2. The high-adhesion biomass-based acrylic pressure-sensitive adhesive according to claim 1, characterized in that, The functional monomers include any one or more of acrylic acid, itaconic acid, glycidyl acrylate, and hydroxypropyl methacrylate.

3. A high-adhesion biomass-based acrylic pressure-sensitive tape, characterized in that, It comprises the following components, and the following parts are by weight: 200 parts of biomass-based acrylate pressure-sensitive adhesive as described in claim 1, 2-10 parts of tackifying resin, and 0.2-1 parts of crosslinking agent; The tackifying resin is rosin resin; The crosslinking agent is aluminum acetylacetonate; The preparation method of the high-adhesion biomass-based acrylate pressure-sensitive adhesive tape is as follows: by weight, 2-10 parts of tackifying resin and 0.2-1 parts of crosslinking agent are added to 200 parts of biomass-based acrylate pressure-sensitive adhesive, stirred evenly, and after the bubbles in the adhesive solution basically disappear after 15-30 minutes, it is coated on PET release film and heated in an oven at 90-110℃ for 2-3 hours to obtain the biomass-based acrylate pressure-sensitive adhesive tape.

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