Anti-discoloration shrink-resistant digital tape and method of making the same

Abstract

This invention provides a colorfast and shrinkage-resistant digital tape and its preparation method. The digital tape comprises, from bottom to top: a PET substrate layer and an acrylic pressure-sensitive adhesive. The raw materials for preparing the acrylic pressure-sensitive adhesive include the following components in parts by weight: 50-80 parts acrylic prepolymer, 1-5 parts antioxidant, 1-10 parts curing agent, 1-10 parts colorfastness additive, 1-10 parts anti-shrinkage agent, and 1-5 parts pigment. The digital tape prepared by this invention has high peel strength, good adhesion, and is colorfast, shrinkage-resistant, has high material stability, and a long service life.

Description

Technical Field

[0001] This invention belongs to the field of adhesive tape technology, and particularly relates to a digital adhesive tape that is resistant to discoloration and shrinkage and its preparation method. Background Technology

[0002] With the rapid development of industries such as electronic information, digital identification, and precision manufacturing, digital tape, as a type of functional tape with specific functions, has become an indispensable key auxiliary material. Digital tape typically uses PET (polyethylene terephthalate), PI (polyimide), PVC (polyvinyl chloride), or OPP (oriented polypropylene) as the base material, and the surface is coated with a functional adhesive layer with specific adhesion, insulation, or marking properties. It must not only meet the basic functions of bonding and fixing, but also ensure the clear readability and long-term stability of the surface coding and recording.

[0003] However, existing digital tapes suffer from two particularly prominent technical defects in terms of long-term reliability: First, poor resistance to discoloration. The PVC substrate or acrylic adhesive commonly used in digital tapes contains unstable molecular structures. When exposed to ultraviolet radiation, high temperature, or humid environments for a long time, they are prone to photo-oxidative degradation and thermal aging, resulting in obvious yellowing, darkening, or color migration of the tape. Second, insufficient dimensional stability and susceptibility to shrinkage. Most substrates are thermoplastic materials, which retain internal stress during the production process and are highly sensitive to temperature changes. When heated, molecular chain segments relax and rearrange, causing irreversible shrinkage deformation of the tape. This may lead to the tape edges lifting, weakening the bonding reliability, or even complete detachment.

[0004] Therefore, how to provide a digital tape that is resistant to discoloration and shrinkage is a problem that this invention urgently needs to solve. Summary of the Invention

[0005] The purpose of this invention is to provide a colorfast and shrinkage-resistant digital tape and its preparation method, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides a colorfast and shrinkage-resistant digital tape and its preparation method. The digital tape comprises, from bottom to top, a PET substrate layer and an acrylic pressure-sensitive adhesive. The raw materials for preparing the acrylic pressure-sensitive adhesive include the following components in parts by weight: 50-80 parts of acrylic prepolymer, 1-5 parts of antioxidant, 1-10 parts of curing agent, 1-10 parts of colorfastness additive, 1-10 parts of anti-shrinkage agent, and 1-5 parts of pigment. The anti-discoloration additive is stearic acid-modified nano-cerium dioxide.

[0007] As a further improvement, the synthesis of the anti-discoloration additive includes the following steps: (1) Add cerium carbonate to nitric acid and stir to obtain solution one; add ammonium carbonate to ammonium bicarbonate and stir to obtain solution two; at room temperature, slowly add solution one to solution two and mix evenly, then heat and age, after aging, post-process to obtain nano cerium dioxide; (2) Place the nano-cerium dioxide obtained in step (1) in anhydrous ethanol and heat and stir under reflux. After reflux is completed, add stearic acid and continue stirring to react. After the reaction is completed, perform post-treatment to obtain the anti-discoloration additive.

[0008] As a further improvement, the particle size of the anti-discoloration additive is 5-20 nm.

[0009] As a further improvement, the antioxidant is at least one of antioxidant 1010, antioxidant 1076, and antioxidant 264.

[0010] For better antioxidant effect, the antioxidant is preferably antioxidant 1076.

[0011] As a further improvement, the curing agent is a diisocyanate-based curing agent.

[0012] As a further improvement, the curing agent is at least one selected from 4,4-diisocyanate dicyclohexylmethane, hexamethylene diisocyanate, and isophorone diisocyanate.

[0013] For better curing effect and resistance to yellowing, the curing agent is preferably 4,4-diisocyanate dicyclohexylmethane.

[0014] As a further improvement, the anti-shrinkage agent is at least one of nano-calcium carbonate, nano-montmorillonite, and polysiloxane.

[0015] For better anti-shrinkage properties, the anti-shrinkage agent is preferably a polysiloxane with a molecular weight of 7000-10000.

[0016] As a further improvement, the pigment is blue ink.

[0017] This invention also provides a method for preparing a colorfast and shrinkage-resistant digital adhesive tape, characterized by comprising the following steps: (1) Mix the acrylic prepolymer, antioxidant, anti-shrinkage agent and pigment according to the weight parts, and then add the anti-discoloration additive and curing agent to continue mixing to obtain acrylic pressure-sensitive adhesive; (2) The acrylic pressure-sensitive adhesive is evenly coated on the PET substrate, dried at 120°C, and then cured at 50°C, rolled up and cut to obtain a digital tape that is resistant to discoloration and shrinkage.

[0018] As a further improvement, the acrylic pressure-sensitive adhesive is coated on a PET substrate with a thickness of 0.015-0.030 mm.

[0019] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a colorfast and shrinkage-resistant digital tape and its preparation method. The resulting digital tape exhibits high peel strength, indicating good adhesion. After UV aging testing, there are no significant changes, good adhesion, and a lower color difference value, indicating that the digital tape prepared by this invention has good UV absorption capacity, is resistant to yellowing and UV aging, has high material stability, and a long service life. It also has a low thermal shrinkage rate, indicating high dimensional stability and is less prone to uneven internal stress and shrinkage deformation due to temperature changes. Stearic acid-modified nano-cerium dioxide can reduce the surface energy of particles, improve the dispersibility of cerium dioxide powder, and enhance the ultraviolet absorption effect of cerium dioxide. When applied to the preparation of digital tape, it can work synergistically with antioxidants to enhance the anti-discoloration and anti-aging properties of digital tape. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the anti-discoloration and shrinkage resistant digital tape prepared in Example 1. Detailed Implementation

[0021] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0022] In the following examples, except for the anti-discoloration additive, sodium dodecylbenzenesulfonate modified nano-cerium dioxide, and acrylic prepolymer, all other compound monomers and related reagents used can be purchased from the market. Among them, the PET substrate was purchased from Huizhou Boyi Technology Co., Ltd., brand name 1; the polysiloxane was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd., model number llb75354; and the blue ink was purchased from Suzhou Jixin Trading Co., Ltd.

[0023] The synthesis of anti-discoloration additives includes the following steps: (1) Add 23g of cerium carbonate to 100mL of nitric acid and stir to obtain solution one; add 1.54g of ammonium carbonate to 160mL of ammonium bicarbonate with a molar concentration of 1mol / L and stir to obtain solution two; at room temperature, slowly add solution one to solution two and mix evenly, then heat to 80℃ and age for 4h. After aging, cool, filter and dry, and calcine at 500℃ for 4h to obtain nano-cerium dioxide. (2) Take 5g of nano-cerium dioxide obtained in step (1) and place it in a flask containing 150mL of anhydrous ethanol. Stir and reflux at 70℃ for 30min. After reflux, add 0.125g of stearic acid and continue stirring for 1h. After the reaction is complete, cool and filter, and dry at 80℃ to obtain the anti-discoloration additive.

[0024] The synthesis of sodium dodecylbenzenesulfonate modified nano-cerium dioxide includes the following steps: (1) Add 23g of cerium carbonate to 100mL of nitric acid and stir to obtain solution one; add 1.54g of ammonium carbonate to 160mL of ammonium bicarbonate with a molar concentration of 1mol / L and stir to obtain solution two; at room temperature, slowly add solution one to solution two and mix evenly, then heat to 80℃ and age for 4h. After aging, cool, filter and dry, and calcine at 500℃ for 4h to obtain nano-cerium dioxide. (2) Take 5g of nano-cerium dioxide obtained in step (1) and place it in a flask containing 150mL of anhydrous ethanol. Stir and reflux at 70℃ for 20min. After reflux, add 0.153g of sodium dodecylbenzenesulfonate and continue stirring for 1h. After the reaction is complete, cool and filter, and dry at 80℃ to obtain sodium dodecylbenzenesulfonate modified nano-cerium dioxide.

[0025] The synthesis of acrylic acid prepolymers includes the following steps: (1) Under a nitrogen atmosphere, 10g of methyl methacrylate, 5g of butyl acrylate, 3g of isobornyl methacrylate, 0.5g of hydroxyethyl acrylate, 0.05g of benzoyl peroxide and 40g of ethyl acetate were added to a flask and stirred and refluxed at 80°C for 30 min to obtain a pre-emulsion. (2) Slowly add a mixture of 25g methyl methacrylate, 10g butyl acrylate, 5g isobornyl methacrylate, 1g hydroxyethyl acrylate and 0.1g benzoyl peroxide to step (1). The addition is completed within 1 hour, and the reaction is kept at 80°C for 3 hours. After the reaction is completed, the temperature is lowered to room temperature to obtain acrylic prepolymer.

[0026] The preparation methods of Examples 1-3 and Comparative Examples 1-2 include the following steps: (1) Mix the acrylic prepolymer, antioxidant, anti-shrinkage agent and pigment according to the weight parts, and then add the anti-discoloration additive and curing agent to continue mixing to obtain acrylic pressure-sensitive adhesive; (2) The acrylic pressure-sensitive adhesive is evenly coated on the PET substrate, dried and molded, then cured, rolled and cut to obtain a digital tape that is resistant to discoloration and shrinkage.

[0027] The components and parts by weight used in Examples 1-3 and Comparative Examples 1-2 are shown in Table 1 below: Table 1

[0028] The digital tapes prepared in Examples 1-3 and Comparative Examples 1-2 were tested for peel strength, UV aging resistance, yellowing resistance, and heat shrinkage rate. The specific test methods are as follows: Peel strength: Tested according to ASTM D3330 standard, using a peel strength tester to test the 180° peel strength; UV aging resistance: Using a UV aging chamber, the digital tape was placed under a UVA-340 lamp at a vertical irradiation distance of 20cm. After one week of UV aging, it was taken out and the surface cracking phenomenon and the change in the adhesion of the adhesive layer were observed. Yellowing resistance: Using a colorimeter, the color values ​​b1 and b2 of the digital tape before and after UV aging were tested, and the color difference value was calculated. b, b = b2 - b1; Heat shrinkage rate: According to GB / T 34848-2017 standard, bake at 110℃ for 3h, record the longitudinal values ​​L0 and L before and after baking, and calculate the heat shrinkage rate R, R=(L0-L) / L0×100%.

[0029] The test results are shown in Table 2: Table 2

[0030] As can be seen from the test results of Example 1 and Comparative Examples 1-2 in Table 2, compared with the use of sodium dodecylbenzenesulfonate-modified nano-cerium dioxide in the preparation of digital tape, or the direct use of nano-cerium dioxide in the preparation of digital tape, the digital tape prepared using stearic acid-modified nano-cerium dioxide as an anti-discoloration additive has higher peel strength, better adhesion, and no significant changes after UV aging test, exhibiting good adhesion and a low color difference value. b<0.2 and heat shrinkage rate R<0.5%, indicating good resistance to discoloration and shrinkage, high material stability, and long service life.

[0031] The test results of Examples 1-3 show that the digital tape prepared by the method provided by the present invention has high peel strength, indicating good adhesion performance; there is no significant change after ultraviolet aging test, good adhesion, and lower color difference value, indicating that the digital tape prepared by the present invention has good ultraviolet absorption capacity, resistance to yellowing and ultraviolet aging, high material stability, long service life, and low thermal shrinkage rate, indicating high dimensional stability of the material and that it is not prone to uneven internal stress or shrinkage deformation due to temperature changes.

[0032] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A digital tape that is resistant to discoloration and shrinkage, characterized in that, The digital tape comprises, from bottom to top: a PET substrate layer and an acrylic pressure-sensitive adhesive. The raw materials for preparing the acrylic pressure-sensitive adhesive include the following components in parts by weight: 50-80 parts of acrylic prepolymer, 1-5 parts of antioxidant, 1-10 parts of curing agent, 1-10 parts of anti-discoloration agent, 1-10 parts of anti-shrinkage agent, and 1-5 parts of pigment. The anti-discoloration additive is stearic acid-modified nano-cerium dioxide.

2. The anti-discoloration and shrinkage resistant digital tape according to claim 1, characterized in that, The synthesis of the anti-discoloration additive includes the following steps: (1) Add cerium carbonate to nitric acid and stir to obtain solution one; add ammonium carbonate to ammonium bicarbonate and stir to obtain solution two; at room temperature, slowly add solution one to solution two and mix evenly, then heat and age, after aging, post-process to obtain nano cerium dioxide; (2) Place the nano-cerium dioxide obtained in step (1) in anhydrous ethanol and heat and stir under reflux. After reflux is completed, add stearic acid and continue stirring to react. After the reaction is completed, perform post-treatment to obtain the anti-discoloration additive.

3. The anti-discoloration and shrinkage resistant digital tape according to claim 2, characterized in that, The particle size of the anti-discoloration additive is 5-20 nm.

4. The anti-discoloration and shrinkage resistant digital tape according to claim 1, characterized in that, The antioxidant is at least one of antioxidant 1010, antioxidant 1076, and antioxidant 264.

5. The anti-discoloration and shrinkage resistant digital tape according to claim 1, characterized in that, The curing agent is a diisocyanate-based curing agent.

6. The anti-discoloration and shrinkage resistant digital tape according to claim 1, characterized in that, The curing agent is at least one of 4,4-diisocyanate dicyclohexylmethane, hexamethylene diisocyanate, and isophorone diisocyanate.

7. The anti-discoloration and shrinkage resistant digital tape according to claim 1, characterized in that, The anti-shrinkage agent is at least one of nano-calcium carbonate, nano-montmorillonite, and polysiloxane.

8. The anti-discoloration and shrinkage resistant digital tape according to claim 1, characterized in that, The pigment is blue ink.

9. A method for preparing a colorfast and shrink-resistant digital adhesive tape according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Mix the acrylic prepolymer, antioxidant, anti-shrinkage agent and pigment according to the weight parts, and then add the anti-discoloration additive and curing agent to continue mixing to obtain acrylic pressure-sensitive adhesive; (2) The acrylic pressure-sensitive adhesive is evenly coated on the PET substrate, dried and molded, then cured, rolled and cut to obtain a digital tape that is resistant to discoloration and shrinkage.

10. The anti-discoloration and shrinkage resistant digital tape according to claim 9, characterized in that, The acrylic pressure-sensitive adhesive is coated on a PET substrate with a thickness of 0.015-0.030 mm.

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