High-stickiness adhesive tape for cotton coating and preparation method of high-stickiness adhesive tape

Abstract

The invention relates to a high-adhesion adhesive tape for cotton coating and a preparation method of the high-adhesion adhesive tape, and belongs to the technical field of pressure-sensitive adhesives. The adhesive tape consists of a bottom film, a high-viscosity pressure-sensitive adhesive adhered to the bottom film and a release film adhered to the surface, wherein the high-viscosity pressure-sensitive adhesive is prepared from the following components in parts by weight: 100 parts of modified acrylate-based adhesive, 14 to 20 parts of MDI prepolymer, 9 to 12 parts of tackifying resin, 4.5 to 6 parts of filler, 1 to 1.3 parts of dispersing aid, 0.7 to 0.9 part of defoaming agent and 0.12 to 0.15 part of light stabilizer; the high-viscosity pressure-sensitive adhesive takes a modified acrylate-based adhesive as a base material, and is formed by carrying out nucleophilic addition reaction on 4-trimethoxysilyl butyraldehyde and acrylamide and then copolymerizing with an acrylate monomer; the high-viscosity pressure-sensitive adhesive has excellent initial adhesion, can realize rapid film coating of cotton, improves the production efficiency, keeps high permanent adhesion and peel strength, is beneficial to the stability of cotton film coating, and avoids package collapse in the packaging and transferring processes.

Description

Technical Field

[0001] The invention belongs to the technical field of pressure-sensitive adhesives, and in particular relates to a high-adhesion tape for cotton coating and a preparation method thereof. Background Art

[0002] Cotton is an important natural fiber crop, which is widely used in the textile field because of its extremely high softness and good moisture absorption. Cotton fibers are slender and flexible, and can absorb a lot of water. This property makes it very suitable for making various types of fabrics, especially in summer, where its cool wearing experience makes it more popular.

[0003] Traditional cotton picking mainly relies on manual picking, which is labor-intensive and inefficient. With the development of agriculture, agricultural machinery has been continuously innovated, and some cotton pickers have appeared on the market. These cotton pickers put cotton into packaging film and seal it, which greatly improves the cotton harvesting efficiency. However, in actual production, the problem of bag collapse often occurs due to unreliable sealing, which seriously limits the packaging efficiency of cotton pickers; in the prior art, cotton packaging mostly uses acrylic pressure-sensitive adhesive tape as a sealing material, which is suitable for a variety of packaging materials and has a relatively stable bonding strength, but it is difficult to meet the needs of large-volume and high-compression packaging; in long-term research, it is found that when the molecular weight of acrylic pressure-sensitive adhesive is low, it is easier to infiltrate the packaging substrate, thereby providing better initial adhesion, but the molecular chain is less entangled, the cohesion of the adhesive layer is low, resulting in low holding force, on the contrary, the initial adhesion is low and the holding force is high, which seriously restricts the application of tape in cotton packaging. Summary of the invention

[0004] In order to solve the technical problems mentioned in the background technology, the object of the present invention is to provide a high-adhesion tape for cotton coating and a preparation method thereof.

[0005] The purpose of the present invention can be achieved by the following technical solutions: A high-adhesion tape for cotton coating, comprising a base film, a high-adhesion pressure-sensitive adhesive adhered to the base film, and a release film attached to the surface, wherein the high-adhesion pressure-sensitive adhesive comprises the following raw materials in parts by weight: 100 parts of modified acrylic base glue, 14-20 parts of MDI prepolymer, 9-12 parts of tackifying resin, 4.5-6 parts of filler, 1-1.3 parts of dispersing aid, 0.7-0.9 parts of defoaming agent and 0.12-0.15 parts of light stabilizer; The modified acrylate base glue is prepared by the following method: Step A1: acrylamide, 4-trimethoxysilylbutyraldehyde and anhydrous ethanol are mixed under the protection of dry nitrogen, triethylamine is added and mixed, the temperature is raised to 75-82° C., stirring is applied at 60-90 rpm, reflux reaction is carried out for 5-7 hours, and ethanol is removed by rotary evaporation after the reaction is completed to obtain a modified monomer; Furthermore, the feed ratio of acrylamide, 4-trimethoxysilylbutyraldehyde, triethylamine and anhydrous ethanol is 10mmol:10mmol:2.5-4mL:20-30mL, and 4-trimethoxysilylbutyraldehyde and acrylamide undergo a nucleophilic addition reaction to form an aldimine compound.

[0006] Step A2: Dry butyl acrylate, isooctyl acrylate, methyl methacrylate and modified monomer, mix and feed, add ethyl acetate to dilute to prepare a batch, preheat the batch to 55-65°C, stir at 80-100rpm, slowly add saturated solutions of benzoyl peroxide and aluminum acetylacetonate, react for 1.8-2.4h, then continue to heat to 80-90°C and reflux for 1-1.5h, cool to room temperature after the reaction is completed, and obtain a modified acrylate base glue.

[0007] Furthermore, the molar ratio of butyl acrylate, isooctyl acrylate, methyl methacrylate and the modified monomer in the batch is 1:0.45-0.6:0.18-0.25:0.22-0.3.

[0008] Furthermore, the solid content of the batch is 40-45wt%.

[0009] Furthermore, the amount of benzoyl peroxide used is 0.7-0.85wt% of the batch material, and the amount of aluminum acetylacetonate used is 0.12-0.18wt% of the batch material.

[0010] Furthermore, the -NCO content of the MDI prepolymer is 3-5wt%.

[0011] Furthermore, the tackifying resin is selected from liquid terpene resins.

[0012] A method for preparing a high-adhesion tape for cotton coating comprises the following steps: Step S1: premixing the filler and the dispersing agent, sequentially adding the modified acrylic base glue, the defoaming agent, the light stabilizer and the tackifying resin, and finally adding the MDI prepolymer, mixing evenly, and vacuum degassing to obtain a high-viscosity pressure-sensitive adhesive; Step S2: coating the high-viscosity pressure-sensitive adhesive on the surface of the base film, drying it under hot air at 80° C. for 5-7 minutes, and then attaching a release film to the surface of the high-viscosity pressure-sensitive adhesive to obtain a high-adhesion tape.

[0013] Beneficial effects of the present invention: The high-viscosity pressure-sensitive adhesive disclosed by the invention has excellent initial adhesion. When applied to cotton film wrapping, the rapid film wrapping of cotton can be realized, the production efficiency can be improved, and high holding force and peeling strength can be maintained, which is beneficial to the stability of the cotton film wrapping and avoids the collapse of the package during packaging and transportation. The high-viscosity pressure-sensitive adhesive uses a modified acrylate-based adhesive as a substrate. The 4-trimethoxysilylbutyraldehyde and acrylamide undergo a nucleophilic addition reaction to form an aldimine compound, which is then copolymerized with an acrylate monomer. Compared with the existing acrylate copolymer for pressure-sensitive adhesive, the modified acrylate-based adhesive has a lower molecular weight and is easier to infiltrate the bonded substrate, thereby providing good initial adhesion. During the bonding process, the aldimine structure introduced into the side chain of the copolymer by the modified monomer contacts water and is slowly hydrolyzed, exposing the active amino group to be cross-linked with the MDI prepolymer, forming a secondary cross-linking network during the bonding process, improving the cohesive force of the pressure-sensitive adhesive layer, and enabling the pressure-sensitive adhesive to provide good holding force and peeling strength. DETAILED DESCRIPTION

[0014] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Example 1, preparing a high-adhesion tape for cotton film coating, the specific implementation process is as follows: (1) Preparation of modified acrylate-based adhesive Step A1: acrylamide, 4-trimethoxysilylbutyraldehyde and anhydrous ethanol are mixed under the protection of dry nitrogen, and triethylamine is added and mixed, the temperature is raised to 75°C, and stirring is applied at 60rpm, and reflux reaction is carried out for 7h, wherein the feed ratio of acrylamide, 4-trimethoxysilylbutyraldehyde, triethylamine and anhydrous ethanol is 10mmol:10mmol:2.5mL:20mL. After the reaction is completed, ethanol is removed by rotary evaporation to obtain a modified monomer.

[0016] Step A2: Take butyl acrylate, isooctyl acrylate, methyl methacrylate and modified monomer, dry them with hot air, mix them and add ethyl acetate to dilute them to make a batch material, preheat the batch material to 55°C, stir at 80rpm, slowly add saturated solutions of benzoyl peroxide and aluminum acetylacetonate, react for 2.4h, and then continue to heat to 80°C and reflux for 1.5h, wherein the molar ratio of butyl acrylate, isooctyl acrylate, methyl methacrylate and modified monomer is 1:0.6:0.18:0.22, the solid content of the batch material is 40wt%, the amount of benzoyl peroxide is 0.7wt% of the batch material, the amount of aluminum acetylacetonate is 0.18wt% of the batch material, and the reaction is cooled to room temperature to obtain a modified acrylate base glue.

[0017] (2) Preparation of high adhesion tape Ingredients: 100 parts of modified acrylate base glue, which is prepared in this embodiment; 20 parts of MDI prepolymer, which is selected from URECORE M2036 type raw material, with an -NCO (isocyanate group) content of about 3.2wt%; 10 parts of tackifier resin, which is selected from SBT13 type liquid terpene resin; 5 parts of filler, which is selected from A200 type white carbon black; 1 part of dispersing aid, which is selected from DN500 type raw material; 0.7 parts of defoamer, which is selected from T-4201 type raw material; 0.15 parts of light stabilizer, which is selected from hindered amine light stabilizer 292.

[0018] Step S1: In a dry environment, premix the filler and the dispersing aid, add the modified acrylic base glue, defoamer, light stabilizer and tackifying resin in sequence, mix at 60 rpm for 10 minutes, finally add the MDI prepolymer and continue stirring for 30 minutes to mix well, vacuum degas for 5 minutes to make a high-viscosity pressure-sensitive adhesive.

[0019] Step S2: Take the corona-treated PET film as the base film, apply a high-viscosity pressure-sensitive adhesive to the surface of the base film, the coating thickness is about 100 μm, dry it under 80° C. hot air for 5 minutes, and then attach a release film to the surface of the high-viscosity pressure-sensitive adhesive to obtain a high-adhesion tape.

[0020] Example 2, preparing a high-adhesion tape for cotton film coating, the specific implementation process is as follows: (1) Preparation of modified acrylate-based adhesive Step A1: acrylamide, 4-trimethoxysilylbutyraldehyde and anhydrous ethanol are mixed under the protection of dry nitrogen, and triethylamine is added and mixed, the temperature is raised to 82°C, and stirring is applied at 90rpm, and reflux reaction is carried out for 5 hours, wherein the feed ratio of acrylamide, 4-trimethoxysilylbutyraldehyde, triethylamine and anhydrous ethanol is 10mmol:10mmol:4mL:30mL. After the reaction is completed, ethanol is removed by rotary evaporation to obtain a modified monomer.

[0021] Step A2: Take butyl acrylate, isooctyl acrylate, methyl methacrylate and modified monomer, dry them with hot air, mix them and add ethyl acetate to dilute them to make a batch material, preheat the batch material to 65°C, stir at 100rpm, slowly add saturated solutions of benzoyl peroxide and aluminum acetylacetonate, react for 1.8h, and then continue to heat to 90°C and reflux for 1h, wherein the molar ratio of butyl acrylate, isooctyl acrylate, methyl methacrylate and modified monomer is 1:0.45:0.25:0.3, the solid content of the batch material is 45wt%, the amount of benzoyl peroxide is 0.85wt% of the batch material, the amount of aluminum acetylacetonate is 0.12wt% of the batch material, and the reaction is cooled to room temperature to obtain a modified acrylate base glue.

[0022] (2) Preparation of high adhesion tape Ingredients: 100 parts of modified acrylate base glue, which is prepared in this embodiment; 14 parts of MDI prepolymer, which is selected from URECORE M2050 type raw material, with an -NCO (isocyanate group) content of about 4.8wt%; 9 parts of tackifier resin, which is selected from SBT13 type liquid terpene resin; 6 parts of filler, which is selected from A200 type white carbon black; 1.3 parts of dispersing aid, which is selected from DN500 type raw material; 0.9 parts of defoamer, which is selected from T-4201 type raw material; 0.12 parts of light stabilizer, which is selected from hindered amine light stabilizer 292.

[0023] Step S1: In a dry environment, premix the filler and the dispersing aid, add the modified acrylic base glue, defoamer, light stabilizer and tackifying resin in sequence, mix at 60 rpm for 10 minutes, finally add the MDI prepolymer and continue stirring for 30 minutes to mix well, vacuum degas for 5 minutes to make a high-viscosity pressure-sensitive adhesive.

[0024] Step S2: taking the corona-treated PET film as the base film, coating the high-viscosity pressure-sensitive adhesive on the surface of the base film, the coating thickness is about 100 μm, drying under 80° C. hot air for 7 minutes, and then attaching a release film to the surface of the high-viscosity pressure-sensitive adhesive to obtain a high-adhesion tape.

[0025] Example 3, preparing a high-adhesion tape for cotton film coating, the specific implementation process is as follows: (1) Preparation of modified acrylate-based adhesive Step A1: acrylamide, 4-trimethoxysilylbutyraldehyde and anhydrous ethanol are mixed under the protection of dry nitrogen, and triethylamine is added to mix, the temperature is raised to 78°C, and stirring is applied at 60rpm. Reflux reaction is carried out for 5.5h, wherein the feed ratio of acrylamide, 4-trimethoxysilylbutyraldehyde, triethylamine and anhydrous ethanol is 10mmol:10mmol:3.5mL:25mL. After the reaction is completed, ethanol is removed by rotary evaporation to obtain a modified monomer.

[0026] Step A2: Take butyl acrylate, isooctyl acrylate, methyl methacrylate and modified monomer, dry them with hot air, mix them and add ethyl acetate to dilute them to make a batch material, preheat the batch material to 60°C, stir at 80rpm, slowly add saturated solutions of benzoyl peroxide and aluminum acetylacetonate, react for 2h, and then continue to heat to 85°C and reflux for 1.2h, wherein the molar ratio of butyl acrylate, isooctyl acrylate, methyl methacrylate and modified monomer is 1:0.5:0.22:0.25, the solid content of the batch material is 42wt%, the amount of benzoyl peroxide is 0.75wt% of the batch material, the amount of aluminum acetylacetonate is 0.14wt% of the batch material, and the reaction is cooled to room temperature to obtain a modified acrylate base glue.

[0027] (2) Preparation of high adhesion tape Ingredients: 100 parts of modified acrylate base glue, which is prepared in this embodiment; 16 parts of MDI prepolymer, which is selected from URECORE M2040 type raw material, with an -NCO (isocyanate group) content of about 3.8wt%; 12 parts of tackifier resin, which is selected from SBT13 type liquid terpene resin; 4.5 parts of filler, which is selected from A200 type white carbon black; 1 part of dispersing aid, which is selected from DN500 type raw material; 0.9 parts of defoamer, which is selected from T-4201 type raw material; 0.14 parts of light stabilizer, which is selected from hindered amine light stabilizer 292.

[0028] Step S1: In a dry environment, premix the filler and the dispersing aid, add the modified acrylic base glue, defoamer, light stabilizer and tackifying resin in sequence, mix at 60 rpm for 10 minutes, finally add the MDI prepolymer and continue stirring for 30 minutes to mix well, vacuum degas for 5 minutes to make a high-viscosity pressure-sensitive adhesive.

[0029] Step S2: taking the corona-treated PET film as the base film, coating the high-viscosity pressure-sensitive adhesive on the surface of the base film, the coating thickness is about 100 μm, drying under 80° C. hot air for 6 minutes, and then attaching a release film to the surface of the high-viscosity pressure-sensitive adhesive to obtain a high-adhesion tape.

[0030] Example 4, preparing a high-adhesion tape for cotton film coating, the specific implementation process is as follows: (1) Preparation of modified acrylate-based adhesive Step A1: acrylamide, 4-trimethoxysilylbutyraldehyde and anhydrous ethanol are mixed under the protection of dry nitrogen, and triethylamine is added to mix, the temperature is raised to 80°C, and stirring is applied at 90rpm. Reflux reaction is carried out for 5.5h, wherein the feed ratio of acrylamide, 4-trimethoxysilylbutyraldehyde, triethylamine and anhydrous ethanol is 10mmol:10mmol:3.2mL:28mL. After the reaction is completed, ethanol is removed by rotary evaporation to obtain a modified monomer.

[0031] Step A2: Take butyl acrylate, isooctyl acrylate, methyl methacrylate and modified monomer, dry them with hot air, mix them and add ethyl acetate to dilute them to make a batch material, preheat the batch material to 65°C, stir at 100rpm, slowly add saturated solutions of benzoyl peroxide and aluminum acetylacetonate, react for 2.2h, and then continue to heat to 85°C and reflux for 1.5h, wherein the molar ratio of butyl acrylate, isooctyl acrylate, methyl methacrylate and modified monomer is 1:0.55:0.2:0.25, the solid content of the batch material is 45wt%, the amount of benzoyl peroxide is 0.82wt% of the batch material, the amount of aluminum acetylacetonate is 0.15wt% of the batch material, and the reaction is cooled to room temperature to obtain a modified acrylate base glue.

[0032] (2) Preparation of high adhesion tape Ingredients: 100 parts of modified acrylate base glue, which is prepared in this embodiment; 18 parts of MDI prepolymer, which is selected from URECORE M2040 type raw material, with an -NCO (isocyanate group) content of about 3.8wt%; 11 parts of tackifying resin, which is selected from SBT13 type liquid terpene resin; 5.5 parts of filler, which is selected from A200 type white carbon black; 1.1 parts of dispersing aid, which is selected from DN500 type raw material; 0.8 parts of defoaming agent, which is selected from T-4201 type raw material; 0.12 parts of light stabilizer, which is selected from hindered amine light stabilizer 292.

[0033] Step S1: In a dry environment, premix the filler and the dispersing aid, add the modified acrylic base glue, defoamer, light stabilizer and tackifying resin in sequence, mix at 60 rpm for 10 minutes, finally add the MDI prepolymer and continue stirring for 30 minutes to mix well, vacuum degas for 5 minutes to make a high-viscosity pressure-sensitive adhesive.

[0034] Step S2: taking the corona-treated PET film as the base film, coating the high-viscosity pressure-sensitive adhesive on the surface of the base film, the coating thickness is about 100 μm, drying under 80° C. hot air for 6 minutes, and then attaching a release film to the surface of the high-viscosity pressure-sensitive adhesive to obtain a high-adhesion tape.

[0035] Comparative Example 1, referring to Example 4, does not add the modified monomer to the raw materials for preparing the modified acrylate base glue, and the rest of the implementation process is exactly the same.

[0036] Comparative Example 2, referring to Example 4, uses QUICKMASTER CT-5030 acrylic adhesive to replace the high-viscosity pressure-sensitive adhesive, and the rest of the implementation process is exactly the same.

[0037] The GPC method was used to detect the weight average molecular weight of the modified acrylic base glue in the above embodiment and the adhesive in the comparative example; the initial adhesion of the tape was detected according to the GB / T 4852-2002 standard; the lasting adhesion of the tape was detected according to the GB / T 4851-2014 standard, the bonding substrate was a PE board, and after pasting, it was rolled back and forth with a force of 2 kg for 2 times, and the lasting adhesion tensile force was 1 kg; the peel strength of the tape was detected according to the GB / T2792-2014 standard, and the peel rate was 200 mm / min; the specific test results are shown in Table 1: Table 1

[0038] It can be seen from the test results in Table 1 that the polymer weight-average molecular weight of the pressure-sensitive adhesive in the adhesive tape of the embodiment is relatively small, has relatively high initial adhesion and peel strength, and maintains relatively high holding force, which is beneficial to the rapid and stable coating of cotton.

[0039] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0040] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A high-adhesion tape for cotton wrapping, comprising a base film, a high-adhesion pressure-sensitive adhesive adhered to the base film, and a release film attached to the surface, characterized in that: The high-viscosity pressure-sensitive adhesive comprises the following raw materials in parts by weight: 100 parts of modified acrylate base glue, 14-20 parts of MDI prepolymer, 9-12 parts of tackifying resin, 4.5-6 parts of filler, 1-1.3 parts of dispersing aid, 0.7-0.9 parts of defoaming agent and 0.12-0.15 parts of light stabilizer; The modified acrylate base glue is prepared by the following method: Step A1: acrylamide, 4-trimethoxysilylbutyraldehyde and anhydrous ethanol are mixed under the protection of dry nitrogen, triethylamine is added and mixed, the temperature is raised to 75-82° C., and the mixture is stirred and refluxed for 5-7 hours. After the reaction is completed, the ethanol is removed by rotary evaporation to obtain a modified monomer; Step A2: Dry butyl acrylate, isooctyl acrylate, methyl methacrylate and modified monomer, mix and feed, add ethyl acetate to dilute to prepare a batch material, preheat the batch material to 55-65°C, stir and slowly add saturated solutions of benzoyl peroxide and aluminum acetylacetonate, react for 1.8-2.4h, then continue to heat to 80-90°C and reflux for 1-1.5h, cool to room temperature after the reaction is completed, and obtain a modified acrylate base glue.

2. A high adhesion tape for cotton wrapping according to claim 1, characterized in that: The feed ratio of acrylamide, 4-trimethoxysilylbutyraldehyde, triethylamine and anhydrous ethanol is 10mmol:10mmol:2.5-4mL:20-30mL.

3. A high adhesion tape for cotton wrapping according to claim 2, characterized in that: The molar ratio of butyl acrylate, isooctyl acrylate, methyl methacrylate and modified monomer in the batch is 1:0.45-0.6:0.18-0.25:0.22-0.

3.

4. A high-adhesion tape for cotton wrapping according to claim 3, characterized in that: The solid content of the batch is 40-45wt%.

5. The high-adhesion tape for cotton wrapping according to claim 3, characterized in that: The amount of benzoyl peroxide used is 0.7-0.85wt% of the batch material, and the amount of aluminum acetylacetonate used is 0.12-0.18wt% of the batch material.

6. The high-adhesion tape for cotton wrapping according to claim 3, characterized in that: The -NCO content of the MDI prepolymer is 3-5wt%.

7. The high-adhesion tape for cotton wrapping according to claim 1, characterized in that: The tackifying resin is a liquid terpene resin.

8. A method for preparing the high-adhesion tape for cotton coating according to any one of claims 1 to 7, characterized in that: The steps include: Step S1: premixing the filler and the dispersing agent, sequentially adding the modified acrylic base glue, the defoaming agent, the light stabilizer and the tackifying resin, and finally adding the MDI prepolymer, mixing evenly, and vacuum degassing to obtain a high-viscosity pressure-sensitive adhesive; Step S2: coating the high-viscosity pressure-sensitive adhesive on the surface of the base film, drying it under hot air at 80° C. for 5-7 minutes, and then attaching a release film to the surface of the high-viscosity pressure-sensitive adhesive to obtain a high-adhesion tape.

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