Environment-friendly adhesive and preparation method thereof

Abstract

The invention discloses an environment-friendly adhesive and a preparation method thereof, and the environment-friendly adhesive comprises the following components in percentage by weight: 0.5-1.5% of 2-ethylhexyl acrylate and hydroxyethyl acrylate, 10-20% of styrene, 1-2% of itaconic acid, 0.5% of azodiisobutyronitrile, 5-10% of acrylic acid, 0.1% of a retarder and 0.1% of an antioxidant. According to the invention, while high adhesion and high light transmittance are maintained, the acrylate is added as a part of soft monomer, so that the cohesion, low temperature resistance and adhesion of the hot melt adhesive are improved.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to an environmentally friendly adhesive and its preparation method. Background Technology

[0002] Acrylic hot melt adhesives are a type of hot melt adhesive that can bond to various substrates without leaving any residue on the substrate surface after removal. However, they also have many drawbacks, such as poor adhesion at low temperatures and poor flexibility, which hinder the further development of acrylic hot melt adhesives. The properties of hot melt adhesives change with temperature. When the temperature rises to a certain high temperature or drops to a certain low temperature, the performance of the hot melt adhesive decreases, weakening the bond strength to the material and ultimately affecting the material's strength. For example, a car operating at -30°C is prone to breakage if its attached hot melt adhesive has poor low-temperature resistance. Currently, common low-temperature resistant hot melt adhesives mainly include polyamide hot melt adhesives and hot melt adhesives prepared based on butyl rubber. Some are prepared by mixing butyl rubber with epoxy resin. Although existing low-temperature resistant hot melt adhesives possess certain low-temperature resistance and flexibility, with the continuous development of hot melt adhesives, the environments in which they are applied are becoming increasingly complex, thus placing higher demands on low-temperature resistant hot melt adhesives.

[0003] Patent CN113773766A invented a low-temperature stretchable flexible hot melt adhesive. It involves melting and mixing silicone-modified epoxy resin with butyl rubber, then adding polymethyl methacrylate, syndiotactic styrene, polyethylene, etc., and achieving crosslinking through an ultraviolet absorber, thus preparing a low-temperature resistant hot melt adhesive. Patents CN113604172A and CN111057487A mainly use ethylene copolymers with different melt indices as the base material, adding acrylic adhesives and other additives to prepare temperature-resistant hot melt adhesives. The temperature resistance is mainly achieved by controlling the melt index after mixing different ethylene copolymers. All of these methods are achieved through blending, which presents the problem of small molecule migration and poor aging resistance over time. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an environmentally friendly adhesive and its preparation method. While maintaining high adhesion and high light transmittance, acrylate is added to act as a part of the soft monomer, which improves the cohesion, low temperature resistance and adhesion of the hot melt adhesive.

[0005] To address the aforementioned technical problems, this invention provides an environmentally friendly adhesive comprising, by weight percentage: isooctyl acrylate, hydroxyethyl acrylate 0.5-1.5%, styrene 10-20%, tannin 1-2%, azobisisobutyronitrile 0.5%, acrylic acid 5-10%, retarder 0.1%, and antioxidant 0.1%.

[0006] Furthermore, the retarder is a mixture of tert-butanol and triethylamine in a weight ratio of 2:1.

[0007] Furthermore, the antioxidant is a mixture of antioxidant 168 and antioxidant 1010.

[0008] A method for preparing an environmentally friendly adhesive includes the following steps: (1) Premixing stage: Weigh a certain amount of acrylate monomers and add them to the reactor. Under nitrogen protection, heat the reactor to 45°C. (2) Initiator addition stage: Add azobisisobutyronitrile to the reactor and stir for 60 min at 45°C; (3) Droplet addition reaction stage: Under high-speed stirring, acrylic acid, retarder and antioxidant are added drop by drop to the reactor, and the temperature is raised to react and obtain acrylic acid prepolymer; (4) Curing stage: Pour the acrylic prepolymer into a polytetrafluoroethylene mold and place it in a drying oven to cure, thus obtaining a film.

[0009] Further, after step (2), styrene and furfural are added and stirred for 10 minutes.

[0010] Furthermore, the reaction conditions for step (3) are: temperature 65℃, reaction time 2h.

[0011] Furthermore, the reaction conditions for step (4) are: curing at 40°C in a forced-air drying oven for 12 hours.

[0012] The beneficial effects of this invention are as follows: This invention selects acrylic acid, acrylate monomers, and styrene as raw materials, and prepares two types of hot melt adhesives by adding appropriate amounts of antioxidants and polymerization inhibitors through free basic polymerization. By controlling the content of acrylic acid components, an adhesive with excellent bonding performance is prepared. By adjusting the content of styrene components, the influence of different acrylate monomer contents on the adhesive properties is investigated. While maintaining high adhesion and high light transmittance, the addition of acrylates as some soft monomers improves the cohesive strength, low-temperature resistance, and adhesion of the hot melt adhesive. Attached Figure Description

[0013] Figure 1 This is the synthetic route diagram of the present invention.

[0014] Figure 2 This is a performance analysis diagram of an embodiment of the present invention. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0016] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0017] 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 invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0018] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0019] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0020] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0021] Reference Figures 1 to 2 As shown, the present invention provides an environmentally friendly adhesive, which, by weight percentage, comprises the following components: isooctyl acrylate, hydroxyethyl acrylate 0.5-1.5%, styrene 10-20%, tannin 1-2%, azobisisobutyronitrile 0.5%, acrylic acid 5-10%, retarder 0.1%, and antioxidant 0.1%.

[0022] The polymerization retarder is a mixture of tert-butanol and triethylamine in a weight ratio of 2:1; the antioxidant is a mixture of antioxidant 168 and antioxidant 1010.

[0023] The manufacturing method is as follows: (1) Premixing stage: Weigh a certain amount of acrylate monomers and add them to the reactor. Under nitrogen protection, heat the reactor to 45°C. (2) Initiator addition stage: Add azobisisobutyronitrile to the reactor and stir for 60 min at 45°C; (3) Droplet addition reaction stage: Under high-speed stirring, acrylic acid, retarder and antioxidant are added drop by drop to the reactor, and the temperature is raised to react and obtain acrylic acid prepolymer; (4) Curing stage: Pour the acrylic prepolymer into a polytetrafluoroethylene mold and place it in a drying oven to cure, thus obtaining a film.

[0024] In step (2), styrene and tannic acid are added and stirred for 10 min; the reaction conditions for step (3) are: temperature 65℃, reaction for 2 h; the reaction conditions for step (4) are: curing at 40℃ in a forced-air drying oven for 12 h.

[0025] The following are three different implementation examples: Example 1 Weigh out a certain amount of isooctyl acrylate, hydroxyethyl acrylate (0.5%), styrene (10%), and taurine (1%) and add them to a reaction vessel. Under nitrogen protection, place the flask in an oil bath at 45°C and add a certain amount of azobisisobutyronitrile (0.5%) in 5 portions. Stir at 45°C for 60 min. Then, slowly add acrylic monomer (5%), retarder (0.1%), and antioxidant (0.1%) dropwise. React at 65°C for 2 h to obtain acrylic prepolymer. Pour the prepolymer into a polytetrafluoroethylene mold and place it in a 40°C forced-air drying oven. After curing for 12 h, obtain a film.

[0026] Example 2 Weigh out a certain amount of isooctyl acrylate, hydroxyethyl acrylate (1.0%), styrene (15%), and taurine (1.5%) and add them to a reaction vessel. Under nitrogen protection, place the flask in an oil bath at 45°C and add a certain amount of azobisisobutyronitrile (0.5%) in 5 portions. Stir at 45°C for 60 min. Then, slowly add acrylic monomer (7.5%), retarder (0.1%), and antioxidant (0.1%) dropwise. React at 65°C for 2 h to obtain acrylic prepolymer. Pour the prepolymer into a polytetrafluoroethylene mold and place it in a 40°C forced-air drying oven. After curing for 12 h, obtain a film.

[0027] Example 3 Weigh out a certain amount of isooctyl acrylate, hydroxyethyl acrylate (1.5%), styrene (20%), and taurine (2%) and add them to a reaction vessel. Under nitrogen protection, place the flask in an oil bath at 45°C and add a certain amount of azobisisobutyronitrile (0.5%) in 5 portions. Stir at 45°C for 60 min. Then, slowly add acrylic monomer (10%), retarder (0.1%), and antioxidant (0.1%) dropwise. React at 65°C for 2 h to obtain acrylic prepolymer. Pour the prepolymer into a polytetrafluoroethylene mold and place it in a 40°C forced-air drying oven. After curing for 12 h, obtain a film.

[0028] The key point is: Monomer ratio control: Styrene provides rigidity, hydroxyethyl acrylate enhances polarity, and taurine adjusts crosslinking density; precise weighing is required.

[0029] Reaction conditions: Low temperature initiation at 45℃ reduces side reactions; azobisisobutyronitrile (0.5%) is added in 5 portions to ensure initiation efficiency; the later stage at 65℃ promotes complete polymerization.

[0030] Dropping procedure: Acrylic monomer and retarder (0.1%) should be added slowly to avoid rapid polymerization; antioxidant (0.1%) is used to prevent thermal oxidative degradation.

[0031] Post-treatment: Dry at 40℃ for 12 hours to ensure complete solvent evaporation and avoid residue affecting film performance.

[0032] advantage: Low-temperature reaction: 45℃ conditions reduce energy consumption and decrease the risk of decomposition of heat-sensitive monomers.

[0033] Controlled polymerization: Stepwise feeding and the use of retarders result in a narrower molecular weight distribution and improved colloid uniformity.

[0034] Overall performance: Styrene-acrylate copolymer balances initial tack (styrene contribution) and holding power (acrylate segment flexibility).

[0035] Process stability: Nitrogen protection prevents oxidation, and drying temperature is lower than the glass transition temperature (Tg) to prevent film deformation.

[0036] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. An environmentally friendly adhesive, characterized in that, By weight percentage, it includes the following components: isooctyl acrylate, hydroxyethyl acrylate 0.5-1.5%, styrene 10-20%, taurine 1-2%, azobisisobutyronitrile 0.5%, acrylic acid 5-10%, retarder 0.1%, and antioxidant 0.1%.

2. The environmentally friendly adhesive as described in claim 1, characterized in that, The retarder is a mixture of tert-butanol and triethylamine in a weight ratio of 2:

1.

3. The environmentally friendly adhesive as described in claim 1, characterized in that, The antioxidant is a mixture of antioxidant 168 and antioxidant 1010.

4. A method for preparing an environmentally friendly adhesive as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) Premixing stage: Weigh a certain amount of acrylate monomers and add them to the reactor. Under nitrogen protection, heat the reactor to 45°C. (2) Initiator addition stage: Add azobisisobutyronitrile to the reactor and stir for 60 min at 45°C; (3) Droplet addition reaction stage: Under high-speed stirring, acrylic acid, retarder and antioxidant are added drop by drop to the reactor, and the temperature is raised to react and obtain acrylic acid prepolymer; (4) Curing stage: Pour the acrylic prepolymer into a polytetrafluoroethylene mold and place it in a drying oven to cure, thus obtaining a film.

5. The method for preparing the environmentally friendly adhesive as described in claim 4, characterized in that, After step (2), styrene and furfural are added and stirred for 10 minutes.

6. The method for preparing the environmentally friendly adhesive as described in claim 4, characterized in that, The reaction conditions for step (3) are: temperature 65℃, reaction time 2h.

7. The method for preparing the environmentally friendly adhesive as described in claim 4, characterized in that, The reaction conditions for step (4) are: curing at 40°C in a forced-air drying oven for 12 hours.

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