Acrylic glue with low water drop angle, pressure-sensitive adhesive protective film and preparation method of acrylic glue

Abstract

The invention discloses acrylic glue with a low water drop angle. The acrylic glue is prepared from the following raw materials in percentage by weight: 30%-35% of an acrylic main monomer, 5%-8% of a hydrophilic functional monomer, 1%-1.5% of a crosslinking monomer, 0.1%-0.5% of an initiator, 54.3%-63.6% of an organic solvent and 0.3%-0.7% of hydrophilic filler, the preparation method of the acrylic glue with the low water drop angle comprises the following steps: (1) uniformly mixing an acrylic main monomer, a hydrophilic functional monomer, a crosslinking monomer and 4 / 5 of an organic solvent, adding the mixture into a reaction kettle provided with a stirring paddle, a thermometer and a condensation pipe to obtain a mixed monomer, and continuously introducing nitrogen; (2) heating the mixed monomer in the reaction kettle in a water bath to 70-90 DEG C, adding an initiator, and stirring at a constant speed of 200r / min to fully react for 5-6 hours to obtain a polyacrylate prepolymer; and (3) cooling the polyacrylate prepolymer prepared in the step (2), adding the rest 1 / 5 of the organic solvent for dilution, adding a hydrophilic filler, and uniformly dispersing to obtain the low-water-drop-angle acrylic glue.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and in particular to a low-water-drop-angle acrylic glue, a pressure-sensitive adhesive protective film and a preparation method thereof. Background Art

[0002] The droplet angle is the angle formed between a liquid droplet and a solid surface. It is an important indicator of the wettability of a solid surface and is often used to measure the wettability of a liquid on a solid. The droplet angle reflects the hydrophilicity or hydrophobicity of the solid surface: a smaller droplet angle (θ < 90°) indicates a more hydrophilic surface, while a larger droplet angle (θ > 90°) indicates a more hydrophobic surface.

[0003] The initial water drop angle on glass is approximately 10°. The process requires that the water drop angle on the glass increase to less than 5° after the protective film is removed. However, after a period of time, when applying existing acrylic protective films, low-molecular-weight components in the adhesive layer migrate from the adhesive to the surface of the adhered object, reducing the surface energy of the glass and increasing the water drop angle to approximately 30°. This weakens the interaction between the ink molecules and the glass surface, making it difficult for the ink to adhere firmly to the glass surface. This adversely affects subsequent ink printing and may cause the printed pattern to easily fall off or fade.

[0004] To minimize the water drop angle on the surface of the object pasted with the protective film, a common method is to add hydrophilic components with hydrophilic groups to the adhesive, such as polyvinylpyrrolidone, dimethylolpropionic acid, polyethylene glycol, hydroxyethyl cellulose, and nano-silica. This transfers the hydrophilic components to the surface of the object, enhancing its hydrophilicity and significantly reducing the water drop angle. However, this method increases the amount of adhesive precipitates on the surface, causing severe fogging of the object, especially glass surfaces, which affects subsequent use and does not fundamentally solve the problem.

[0005] Therefore, how to prepare an acrylic glue and a corresponding protective film that can maintain the surface water drop angle of the object being pasted through the protective film. Summary of the Invention

[0006] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a low water drop angle acrylic glue, a pressure-sensitive adhesive protective film and a preparation method thereof.

[0007] The purpose of the present invention is achieved by adopting the following technical solutions: According to an embodiment of the present disclosure, a low water drop angle acrylic glue is provided, comprising the following raw materials in weight percentage: 30%-35% acrylate main monomer, 5%-8% hydrophilic functional monomer, 1%-1.5% cross-linking monomer, 0.1%-0.5% initiator, 54.3%-63.6% organic solvent, and 0.3%-0.7% hydrophilic filler; The method for preparing the low water drop angle acrylic glue comprises the following steps: (1) The acrylic acid ester main monomer, the hydrophilic functional monomer, the cross-linking monomer and 4 / 5 of the organic solvent are mixed evenly, added into a reaction kettle equipped with a stirring blade, a thermometer and a condenser to obtain a mixed monomer, and nitrogen is continuously introduced; (2) Heat the mixed monomers in the reactor to 70-90°C in a water bath, add the initiator, and stir at a speed of 200 r / min to allow the mixture to react fully for 5-6 hours to obtain a polyacrylate prepolymer; (3) Cooling the polyacrylate prepolymer obtained in step (2), adding the remaining 1 / 5 of the organic solvent to dilute it, and adding a hydrophilic filler to disperse it evenly to obtain a low water drop angle acrylic glue.

[0008] As a preferred solution, the acrylic ester main monomer includes one or more of butyl acrylate and isooctyl acrylate.

[0009] As a preferred solution, the hydrophilic functional monomer includes a monomer containing one or more groups selected from the group consisting of hydroxyl group, carboxyl group and ether bond.

[0010] As a preferred solution, the cross-linking monomer includes one or more of ethylene glycol dimethacrylate and N-hydroxymethyl acrylamide.

[0011] As a preferred embodiment, the initiator includes one or more of benzoyl peroxide, lauryl peroxide, azobisisobutyronitrile and azobisvaleronitrile.

[0012] As a preferred solution, the hydrophilic filler includes nano-SiO2 particles.

[0013] The present invention also provides a method for preparing a pressure-sensitive adhesive protective film, wherein the raw materials for the preparation include the low water drop angle acrylic glue described in the above technical solution; The method for preparing the pressure-sensitive adhesive protective film comprises the following steps: A. preparing an acrylic adhesive, mixing the acrylic adhesive with a curing agent, a catalyst, and a solvent and stirring the mixture to obtain a mixed adhesive; B. coating the mixed adhesive prepared in step A on the corona surface of the PET film at a speed of 5 mm / s to form a pressure-sensitive adhesive layer; C. Bake the pressure-sensitive adhesive layer obtained in step B at 110°C for 3-5 minutes, laminate a silicone release film on the baked pressure-sensitive adhesive layer, and then place it in a 50°C oven for aging for 2 days to obtain a pressure-sensitive adhesive protective film.

[0014] The present invention also provides a pressure-sensitive adhesive protective film, which is prepared by the preparation method described in the above technical solution. The pressure-sensitive adhesive protective film includes a silicone oil release layer, a pressure-sensitive adhesive layer and a PET substrate layer from top to bottom.

[0015] In summary, compared with the prior art, the present invention has the following beneficial effects: 1. By selecting acrylate monomers with high reactivity and low volatility as raw materials, when synthesizing the adhesive, there are fewer small molecules remaining in the glue itself, and fewer small molecules transferred from the adhesive layer to the surface of the adhered object, thus solving the problem of increased precipitates caused by small molecule transfer; 2. When synthesizing adhesives, add hydrophilic functional monomers to increase the hydrophilicity of the adhesive; 3. After synthesizing the glue (i.e. polyacrylate prepolymer), add hydrophilic nano-SiO2 particles into it and disperse them evenly so that the hydrophilic nano-SiO2 particles can be transferred to the surface of the object to be attached, thereby reducing the rise of the water drop angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of the pressure-sensitive adhesive protective film of the present invention. DETAILED DESCRIPTION

[0017] The present invention provides a low water drop angle acrylic glue, comprising the following raw materials in weight percentage: 30%-35% of an acrylic ester main monomer, 5%-8% of a hydrophilic functional monomer, 1%-1.5% of a cross-linking monomer, 0.1%-0.5% of an initiator, 54.3%-63.6% of an organic solvent, and 0.3%-0.7% of a hydrophilic filler; The method for preparing the low water drop angle acrylic glue comprises the following steps: (1) The acrylic acid ester main monomer, the hydrophilic functional monomer, the cross-linking monomer and 4 / 5 of the organic solvent are mixed evenly, added into a reaction kettle equipped with a stirring blade, a thermometer and a condenser to obtain a mixed monomer, and nitrogen is continuously introduced; (2) Heat the mixed monomers in the reactor to 70-90°C in a water bath, add the initiator, and stir at a speed of 200 r / min to allow the mixture to react fully for 5-6 hours to obtain a polyacrylate prepolymer; (3) Cooling the polyacrylate prepolymer obtained in step (2), adding the remaining 1 / 5 of the organic solvent to dilute it, and adding a hydrophilic filler to disperse it evenly to obtain a low water drop angle acrylic glue.

[0018] Therefore, this application selects monomers with high reactivity and low volatility as raw materials to reduce the amount of unreacted monomers remaining in the adhesive layer. Furthermore, adding hydrophilic monomers containing polar groups to the acrylic adhesive formula can significantly increase its hydrophilicity, such as acrylic acid and methacrylic acid containing carboxyl groups; hydroxyethyl acrylate and hydroxypropyl acrylate containing hydroxyl groups; and acrylamide and N-hydroxymethyl acrylamide containing amide groups.

[0019] Specifically, the acrylic ester main monomer includes one or more of butyl acrylate and isooctyl acrylate.

[0020] Specifically, the hydrophilic functional monomer includes a monomer containing one or more groups selected from the group consisting of a hydroxyl group, a carboxyl group, and an ether bond.

[0021] Specifically, the cross-linking monomer includes one or more of ethylene glycol dimethacrylate and N-hydroxymethyl acrylamide.

[0022] Specifically, the initiator includes one or more of benzoyl peroxide, lauryl peroxide, azobisisobutyronitrile and azobisvaleronitrile.

[0023] Specifically, the hydrophilic filler includes nano-SiO2 particles.

[0024] Thus, the addition of highly active hydrophilic fillers to the acrylic adhesive in this application can significantly increase the surface energy of the substrate. For example, hydrophilic nano-SiO2 particles can extend the diffusion path of small molecules within the adhesive layer, reducing precipitation on the surface of the substrate, thereby increasing the hydrophilicity of the substrate. Furthermore, the nano-SiO2 particles contain silicon-hydrogen groups (SiOH), which easily form hydrogen bonds with water, thereby increasing the surface energy.

[0025] The present invention also provides a method for preparing a pressure-sensitive adhesive protective film, wherein the raw materials for the preparation include the low water drop angle acrylic glue described in the above technical solution; The method for preparing the pressure-sensitive adhesive protective film comprises the following steps: A. preparing an acrylic adhesive, mixing the acrylic adhesive with a curing agent, a catalyst, and a solvent and stirring the mixture to obtain a mixed adhesive; B. coating the mixed adhesive prepared in step A on the corona surface of the PET film at a speed of 5 mm / s to form a pressure-sensitive adhesive layer; C. Bake the pressure-sensitive adhesive layer obtained in step B at 110°C for 3-5 minutes, laminate a silicone release film on the baked pressure-sensitive adhesive layer, and then place it in a 50°C oven for aging for 2 days to obtain a pressure-sensitive adhesive protective film.

[0026] Thus, the present application obtains a low-migration acrylic adhesive by mixing a certain proportion of acrylate monomer, hydrophilic low-migration monomer, initiator and solvent, obtaining an acrylate prepolymer through polymerization reaction, and then adding nano-SiO2 to the above acrylate prepolymer and uniformly dispersing it.

[0027] The present invention also provides a pressure-sensitive adhesive protective film, which is prepared by the preparation method described in the above technical solution. Figure 1 As shown, the pressure-sensitive adhesive protective film includes a silicone oil release layer 1, a pressure-sensitive adhesive layer 2 and a PET substrate layer 3 from top to bottom.

[0028] The present application improves the effect of acrylic pressure-sensitive adhesive on the water drop angle of the adhered object in two aspects: on the one hand, by adding a hydrophilic acrylate monomer containing a polar group when synthesizing the adhesive, the hydrophilicity of the adhesive is increased; on the other hand, by adding a hydrophilic filler, the surface energy of the adhered object can be significantly increased, thereby reducing the increase in the water drop angle.

[0029] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0030] Example 1 A low water drop angle acrylic glue comprises the following raw materials in percentage by weight: 30% butyl acrylate, 5% hydroxyethyl acrylate, 1% N-hydroxymethyl acrylamide, 0.1% benzoyl peroxide (BPO), 63.6% ethyl acetate, and 0.3% hydrophilic nano-SiO2 particles; The method for preparing the low water drop angle acrylic glue comprises the following steps: (1) Butyl acrylate, hydroxyethyl acrylate, N-hydroxymethyl acrylamide and 4 / 5 of ethyl acetate were mixed evenly, added into a reaction kettle equipped with a stirring blade, a thermometer and a condenser to obtain a mixed monomer, and nitrogen was continuously introduced; (2) The mixed monomers in the reactor were heated to 90°C in a water bath, benzoyl peroxide (BPO) was added, and the mixture was stirred at a speed of 200 r / min for 5 hours to fully react to obtain a polyacrylate prepolymer; (3) The polyacrylate prepolymer prepared in step (2) is cooled, and the remaining 1 / 5 of ethyl acetate is added to dilute it, and hydrophilic nano-SiO2 particles are added and dispersed evenly to obtain a low water drop angle acrylic glue with a solid content of 40%.

[0031] Example 2 A low water drop angle acrylic glue comprises the following raw materials in percentage by weight: 35% butyl acrylate, 8% hydroxyethyl acrylate, 1.5% N-hydroxymethyl acrylamide, 0.5% benzoyl peroxide (BPO), 54.3% organic solvent, and 0.7% hydrophilic nano-SiO2 particles; The method for preparing the low water drop angle acrylic glue comprises the following steps: (1) Butyl acrylate, hydroxyethyl acrylate, N-hydroxymethyl acrylamide and 4 / 5 of ethyl acetate were mixed evenly, added into a reaction kettle equipped with a stirring blade, a thermometer and a condenser to obtain a mixed monomer, and nitrogen was continuously introduced; (2) The mixed monomers in the reactor were heated to 70°C in a water bath, an initiator was added, and the mixture was stirred at a speed of 200 r / min to allow the mixture to react fully for 6 h to obtain a polyacrylate prepolymer; (3) The polyacrylate prepolymer prepared in step (2) is cooled, and the remaining 1 / 5 of ethyl acetate is added to dilute it, and hydrophilic nano-SiO2 particles are added and dispersed evenly to obtain a low water drop angle acrylic glue with a solid content of 40%.

[0032] Example 3 A low water drop angle acrylic glue comprises the following raw materials in weight percentage: 33% butyl acrylate, 6.7% hydroxyethyl acrylate, 1.3% N-hydroxymethyl acrylamide, 0.2% benzoyl peroxide (BPO), 58.2% organic solvent, and 0.6% hydrophilic nano-SiO2 particles; The method for preparing the low water drop angle acrylic glue comprises the following steps: (1) Butyl acrylate, hydroxyethyl acrylate, N-hydroxymethyl acrylamide and 4 / 5 of ethyl acetate were mixed evenly, added into a reaction kettle equipped with a stirring blade, a thermometer and a condenser to obtain a mixed monomer, and nitrogen was continuously introduced; (2) The mixed monomers in the reactor were heated to 80°C in a water bath, an initiator was added, and the mixture was stirred at a speed of 200 r / min to allow the mixture to react fully for 5.5 h to obtain a polyacrylate prepolymer; (3) The polyacrylate prepolymer prepared in step (2) is cooled, and the remaining 1 / 5 of ethyl acetate is added to dilute it, and hydrophilic nano-SiO2 particles are added and dispersed evenly to obtain a low water drop angle acrylic glue with a solid content of 40%.

[0033] Example 4 A method for preparing a pressure-sensitive adhesive protective film comprises the following steps: A. Mixing the acrylic adhesive obtained in Example 1 with a curing agent, a catalyst, and a solvent and stirring uniformly to obtain a mixed adhesive; B. coating the mixed adhesive prepared in step A on the corona surface of the PET film at a speed of 5 mm / s to form a pressure-sensitive adhesive layer; C. Bake the pressure-sensitive adhesive layer obtained in step B at 110°C for 3 minutes, laminate a silicone release film on the baked pressure-sensitive adhesive layer, and then place it in a 50°C oven for aging for 2 days to obtain a pressure-sensitive adhesive protective film.

[0034] Example 5 A method for preparing a pressure-sensitive adhesive protective film comprises the following steps: A. Mixing the acrylic adhesive obtained in Example 2 with a curing agent, a catalyst, and a solvent and stirring uniformly to obtain a mixed adhesive; B. coating the mixed adhesive prepared in step A on the corona surface of the PET film at a speed of 5 mm / s to form a pressure-sensitive adhesive layer; C. Bake the pressure-sensitive adhesive layer obtained in step B at 110°C for 5 minutes, laminate a silicone release film on the baked pressure-sensitive adhesive layer, and then place it in a 50°C oven for aging for 2 days to obtain a pressure-sensitive adhesive protective film.

[0035] The pressure-sensitive adhesive protective film prepared according to Examples 4 and 5 has the following properties: 1) Steel plate peeling force: 5-20gf / 25mm at room temperature; GB / T 2792-2014 "Test method for peel strength of adhesive tapes".

[0036] 2) Water drop angle increase: The water drop angle of the glass was measured before any treatment, obtaining raw data. The protective film was removed from the adhesive film and applied to the glass just tested for water drop angle. The glass was heated at 150°C for 1 hour, the protective film was removed, and the water drop angle after the protective film was applied was measured. The results showed that the protective film of the present invention can reduce the increase in water drop angle of the glass to within 10°, and even to less than 5°.

[0037] 3) Fogging Test: The protective film was cut into half the size of a glass. The laminating film was removed and applied to one side of the glass, leaving the other half of the glass untouched for comparison. The glass with the protective film was placed at 150°C for 1 hour, then removed and cooled to room temperature. The protective film was removed in a well-lit, evenly lit environment. The fogging of the glass after the high temperature exposure was observed for both the glass with and without the protective film. The results showed that the protective film of the present invention caused only slight fogging of the glass.

[0038] The above embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patented invention. It should be noted that those skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention. These variations and improvements are equivalent modifications and improvements to the above embodiments based on the essential technology of the present invention and fall within the scope of protection of the present invention.

Claims

1. A low water drop angle acrylic glue, characterized in that: The raw materials include the following weight percentages: 30%-35% acrylate main monomer, 5%-8% hydrophilic functional monomer, 1%-1.5% crosslinking monomer, 0.1%-0.5% initiator, 54.3%-63.6% organic solvent, and 0.3%-0.7% hydrophilic filler; The method for preparing the low water drop angle acrylic glue comprises the following steps: (1) The acrylic acid ester main monomer, the hydrophilic functional monomer, the cross-linking monomer and 4 / 5 of the organic solvent are mixed evenly, added into a reaction kettle equipped with a stirring blade, a thermometer and a condenser to obtain a mixed monomer, and nitrogen is continuously introduced; (2) Heat the mixed monomers in the reactor to 70-90°C in a water bath, add the initiator, and stir at a speed of 200 r / min to allow the mixture to react fully for 5-6 hours to obtain a polyacrylate prepolymer; (3) Cooling the polyacrylate prepolymer obtained in step (2), adding the remaining 1 / 5 of the organic solvent to dilute it, and adding a hydrophilic filler to disperse it evenly to obtain a low water drop angle acrylic glue.

2. The low drip angle acrylic glue according to claim 1, characterized in that: The acrylic acid ester main monomer includes one or more of butyl acrylate and isooctyl acrylate.

3. The low drip angle acrylic glue according to claim 1, characterized in that: The hydrophilic functional monomer includes a monomer containing one or more groups selected from the group consisting of hydroxyl group, carboxyl group and ether bond.

4. The low drip angle acrylic glue according to claim 1, characterized in that: The cross-linking monomer includes one or more of ethylene glycol dimethacrylate and N-methylol acrylamide.

5. The low drip angle acrylic glue according to claim 1, characterized in that: The initiator includes one or more of benzoyl peroxide, lauryl peroxide, azobisisobutyronitrile and azobisvaleronitrile.

6. The low drip angle acrylic glue according to claim 1, characterized in that: The hydrophilic filler includes nano-SiO2 particles.

7. A method for preparing a pressure-sensitive adhesive protective film, characterized in that: The raw materials for preparation include the low water drop angle acrylic glue according to any one of claims 1 to 7; The method for preparing the pressure-sensitive adhesive protective film comprises the following steps: A. preparing an acrylic adhesive, mixing the acrylic adhesive with a curing agent, a catalyst, and a solvent and stirring the mixture to obtain a mixed adhesive; B. coating the mixed adhesive prepared in step A on the corona surface of the PET film at a speed of 5 mm / s to form a pressure-sensitive adhesive layer; C. Bake the pressure-sensitive adhesive layer obtained in step B at 110°C for 3-5 minutes, laminate a silicone release film on the baked pressure-sensitive adhesive layer, and then place it in a 50°C oven for aging for 2 days to obtain a pressure-sensitive adhesive protective film.

8. A pressure-sensitive adhesive protective film, characterized in that: The pressure-sensitive adhesive protective film is prepared by the preparation method of the pressure-sensitive adhesive protective film according to claim 8. The pressure-sensitive adhesive protective film comprises, from top to bottom, a silicone oil release layer, a pressure-sensitive adhesive layer and a PET substrate layer.

Images