Pressure-sensitive adhesive tape with high environmental protection property and preparation method thereof

Abstract

The invention discloses a high-environment-friendliness pressure-sensitive adhesive tape and a preparation method thereof, and belongs to the technical field of pressure-sensitive adhesive products. The pressure-sensitive adhesive tape is formed by sequentially compounding an environment-friendly acrylate pressure-sensitive adhesive layer, a degradable base material layer and an environment-friendly release layer, wherein the environment-friendly acrylate pressure-sensitive adhesive is prepared by taking a bio-based acrylate monomer as a main polymeric monomer and taking a degradable monomer and a degradable cross-linking agent as auxiliary materials, the degradable base material layer is prepared from a polylactic acid or polycaprolactone material, and the environment-friendly release layer is a water-based organic silicon release agent coating layer. The pressure-sensitive adhesive tape disclosed by the invention has excellent initial adhesion, permanent adhesion and peel strength, can be naturally degraded or harmlessly treated by the environment after being discarded, solves the problems that the traditional pressure-sensitive adhesive tape is difficult to degrade and easily causes continuous environmental pollution, and can be widely applied to multiple fields such as communication equipment, display devices, packaging, electronics, medical treatment and the like.

Description

Technical Field

[0001] This invention relates to the field of pressure-sensitive adhesive products, specifically to a highly environmentally friendly pressure-sensitive adhesive tape and its preparation method. Background Technology

[0002] Pressure-sensitive adhesive tapes are a type of adhesive product that requires no heating and only slight pressure to bond, and are widely used in packaging, electronics, medical, construction, and many other industries. Traditional pressure-sensitive adhesive tapes typically use pressure-sensitive adhesives polymerized from petroleum-based acrylate monomers, combined with non-degradable substrates such as polyethylene and polypropylene. After disposal, they are difficult to degrade naturally and remain in the environment for a long time, causing "white pollution," which is inconsistent with the current trend of green and environmentally friendly development.

[0003] With increasingly stringent environmental policies and rising consumer awareness of environmental protection, the development of biodegradable and environmentally friendly pressure-sensitive tapes has become a research hotspot in the industry.

[0004] For example, Chinese patent CN103865419B discloses an environmentally friendly self-crosslinking pressure-sensitive adhesive tape. This tape includes a substrate layer and a pressure-sensitive adhesive layer, with the adhesive layer located on the upper surface of the substrate layer. A photocatalyst layer is also disposed on the lower surface of the substrate layer. A corona layer is further disposed between the substrate layer and the photocatalyst layer. The multi-layered pressure-sensitive adhesive tape prepared by this invention can effectively remove toxic substances such as formaldehyde from the pressure-sensitive adhesive. It is suitable for use in various applications such as sealing packaging tape, medical tape, double-sided tape, and foamed tape, ensuring it is green, environmentally friendly, formaldehyde-free, benzene-free, safe, and hygienic.

[0005] However, including the aforementioned pressure-sensitive tapes, some environmentally friendly pressure-sensitive tapes on the market currently suffer from problems such as insufficient adhesion, poor holding power, and slow degradation rate, making it difficult to meet the needs of practical applications.

[0006] To address the above problems, this invention provides a highly environmentally friendly pressure-sensitive tape and its preparation method. Summary of the Invention

[0007] The purpose of this invention is to provide a highly environmentally friendly pressure-sensitive tape and its preparation method to solve the problems mentioned in the background art.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a highly environmentally friendly pressure-sensitive tape, comprising an environmentally friendly acrylic pressure-sensitive adhesive layer, a biodegradable substrate layer and an environmentally friendly release layer sequentially laminated together; The environmentally friendly acrylic pressure-sensitive adhesive layer comprises the following components in parts by weight: 40-60 parts of bio-based acrylate soft monomers, 10-20 parts of bio-based acrylate hard monomers, 5-10 parts of functional monomers, 0.05-0.5 parts of biodegradable monomers, 1-3 parts of biodegradable crosslinking agents, 0.3-0.8 parts of initiators, and 1-3 parts of photoinitiators.

[0009] More preferably, the bio-based acrylate soft monomer is at least one of bio-based isooctyl acrylate and bio-based butyl acrylate; the bio-based acrylate hard monomer is at least one of bio-based methyl acrylate and bio-based ethyl acrylate.

[0010] More preferably, the functional monomer is at least one of acrylic acid, methacrylic acid, and acrylamide; the biodegradable crosslinking agent is at least one of triallyl citrate and polylactic acid diacrylate; and the biodegradable monomer is at least one of allyl sulfone compound I and allyl sulfone compound II of the following formula; .

[0011] More preferably, the initiator is at least one of azobisisobutyronitrile and benzoyl peroxide.

[0012] Ideally, the biodegradable substrate layer is made of one of polylactic acid (PLA), polycaprolactone (PCL), or polyhydroxyalkanoate (PHA), and the thickness of the biodegradable substrate layer is 10-50 μm.

[0013] Ideally, the environmentally friendly release layer is a water-based silicone release agent coating layer with a thickness of 0.1-1.2 μm.

[0014] The tape prepared by this invention can be used in communication equipment, display devices, packaging boxes, fixing and covering electronic components, medical breathable tape, and stationery pasting.

[0015] This invention also provides a method for preparing a highly environmentally friendly pressure-sensitive adhesive tape, used to prepare any of the above-mentioned highly environmentally friendly pressure-sensitive adhesive tapes, comprising the following steps: S1, Preparation of environmentally friendly acrylic pressure-sensitive adhesive: Nitrogen gas is introduced for 30 minutes before the reaction to remove oxygen from the system, and the subsequent reaction is carried out in a nitrogen atmosphere; bio-based soft acrylic monomers, bio-based hard acrylic monomers, biodegradable monomers, initiators, and functional monomers are premixed and added to the reactor to prepare a premixed solution. Stirring is started, and the mixed solvent in the reactor is heated to 65-70℃ and kept at a constant temperature for 2 hours to obtain the prepolymer; Cool the system to below 40°C, add 0.01-0.03 parts of MEHQ polymerization inhibitor, and stir thoroughly; then add the biodegradable crosslinking agent and photoinitiator under light-protected conditions, mix evenly, and filter through a filter with a mesh size of 100 or higher; the resulting environmentally friendly acrylic pressure-sensitive adhesive liquid is obtained. S2, tape lamination molding, involves coating a layer of water-based silicone release agent onto the surface of the biodegradable substrate layer that is not coated with pressure-sensitive adhesive through slit extrusion coating or anilox roller coating; then drying it in an oven at 80-100℃ for 3-5 minutes to form an environmentally friendly release layer with a thickness of 0.1-1.2μm. The pressure-sensitive adhesive liquid obtained in step S1 is uniformly coated on one side of the biodegradable substrate layer using a comma doctor blade coating or microgravure coating. Then, it is cured by irradiation with an LED UV light source with a wavelength of 365-395nm and an intensity of 80-120mW / cm² for 30-60 seconds. After curing, it is naturally cooled to room temperature to form a pressure-sensitive adhesive layer with a uniform surface and a thickness of 20-40μm. The composite tape material is cured at room temperature for 24-48 hours to stabilize the pressure-sensitive adhesive properties; finally, it is cut to the required width and wound up to obtain the finished tape.

[0016] Ideally, in step S2, the curing process uses UV curing.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention is highly environmentally friendly. The adhesive layer uses biodegradable acrylate monomers and biodegradable crosslinking agents, the substrate uses biodegradable polylactic acid, polycaprolactone and other materials, and the release layer uses water-based organosilicon release agent. All components meet environmental protection requirements and can be naturally degraded after disposal, with no risk of environmental pollution.

[0018] In this invention, the addition of biodegradable monomers introduces ester groups into the polymer backbone, providing multiple degradation sites for the polymer network. The resulting product can achieve polymer backbone cleavage under alkaline conditions. The addition of biodegradable crosslinking agents can untie the crosslinks between polymer chains. The combined effect of the two can make the polymer degradation more complete.

[0019] This invention has excellent adhesive properties. By rationally proportioning soft monomers, hard monomers and crosslinking agents, the pressure-sensitive adhesive layer has good initial tack, holding power and peel strength, which can meet the application needs of multiple fields such as packaging, electronics and medical.

[0020] The preparation process of this invention is simple, the reaction conditions are mild, and it is easy to industrialize. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The present invention verifies the performance of the adhesive prepared by the present invention through several embodiments and comparative examples. Example 1

[0023] A highly environmentally friendly pressure-sensitive adhesive tape, the raw materials by weight are: 50 parts of bio-based isooctyl acrylate, 15 parts of bio-based methyl acrylate, 8 parts of acrylic acid, 0.08 parts of biodegradable monomer, 1 part of triallyl citrate, 0.5 parts of azobisisobutyronitrile, and 1 part of HMPP; the biodegradable substrate layer is a polylactic acid film with a thickness of 30μm; the environmentally friendly release layer is a water-based silicone release agent with a thickness of 0.4μm.

[0024] Preparation method: 1. Preparation of pressure-sensitive adhesive: After purging nitrogen for 30 min, 50 parts of bio-based isooctyl acrylate, 15 parts of bio-based methyl acrylate, 8 parts of acrylic acid, 0.08 parts of allyl sulfone compound I and 0.5 parts of azobisisobutyronitrile were mixed evenly to prepare a premixed solution, which was then added to a reaction vessel and heated to 68℃. The reaction was carried out at a constant temperature for 2 h, and then cooled to 35℃. 0.02 parts of polymerization inhibitor MEHQ were added, followed by 1 part of degradable crosslinking agent triallyl citrate and photoinitiator HMPP under light-protected conditions. After filtration through a 100-mesh filter, the pressure-sensitive adhesive solution was obtained.

[0025] 2. Tape lamination: A water-based silicone release agent is coated on one side of the polylactic acid substrate and dried to form a release layer; pressure-sensitive adhesive is coated on the other side of the substrate and UV cured for 40 seconds to form a 30μm thick adhesive layer. The finished product is then obtained by winding and slitting. Example 2

[0026] The difference from Example 1 is that, by weight, the raw materials are: 45 parts of bio-based butyl acrylate, 18 parts of bio-based ethyl acrylate, 6 parts of methacrylic acid, 0.1 parts of allyl sulfone compound II, 1.5 parts of polylactic acid diacrylate, and 0.6 parts of azobisisobutyronitrile; the biodegradable substrate layer is a polycaprolactone film with a thickness of 25 μm; and the environmentally friendly release layer is a water-based silicone release agent with a thickness of 0.5 μm. Example 3

[0027] The difference from Example 1 is that, by weight, the raw materials are: 30 parts of bio-based isooctyl acrylate, 20 parts of bio-based butyl acrylate, 12 parts of bio-based methyl acrylate, 7 parts of acrylamide, 0.07 parts of allyl sulfone compound I, 2.5 parts of polylactic acid diacrylate, and 0.4 parts of azobisisobutyronitrile; the biodegradable substrate layer is a polylactic acid-polycaprolactone blend film with a thickness of 35 μm; and the environmentally friendly release layer is a water-based silicone release agent with a thickness of 0.6 μm.

[0028] The finished products were subjected to performance tests according to the following standards: initial tack strength according to GB / T 4852-2002, holding power according to GB / T 4851-2014, 180° peel strength according to GB / T 2792-2014, and degradation performance according to GB / T19277.1-2011.

[0029] The test results are shown in Table 1.

[0030] Table 1 Test Results of Each Embodiment

[0031] The test results show that the pressure-sensitive tape prepared by this invention has excellent adhesion and degradation properties, and fully meets the requirements for the use of environmentally friendly pressure-sensitive tape.

[0032] In addition, the present invention provides two comparative embodiments and three comparative examples for comparison with the embodiments of this application.

[0033] Comparative Example 1 Petroleum-based isooctyl acrylate and petroleum-based methyl acrylate were used as monomers, and ethylene glycol diacrylate was used as a crosslinking agent. The remaining raw materials and preparation method were the same as in Example 1. Test results showed that its initial tack to a No. 11 steel ball was >24h, and its peel strength was 17.8N / 25mm. However, the composting degradation rate after 6 months was only 12%, and its environmental performance was far lower than that of the embodiment of this invention.

[0034] Comparative Example 2 Polyethylene film was used as the substrate, and the remaining raw materials and preparation method were the same as in Example 1. Test results showed that it had good adhesion properties, but the substrate was non-degradable and could easily cause environmental pollution after disposal.

[0035] Basis for setting the scale: 1. Comparative Example 1 (Traditional Petroleum-based Pressure-sensitive Adhesive Tape): Petroleum-based isooctyl acrylate and petroleum-based methyl acrylate were used as polymer monomers, ethylene glycol diacrylate (non-degradable crosslinking agent) was used, polyethylene film was used as the substrate, and solvent-based silicone release agent was used. The preparation process was the same as in Example 1.

[0036] 2. Comparative Example 2 (Environmentally friendly modified pressure-sensitive tape with adhesive layer only): The environmentally friendly acrylic pressure-sensitive adhesive layer formulation of Example 1 of this invention was used, the substrate was replaced with a non-degradable polypropylene film, the release layer was a solvent-based silicone release agent, and the preparation process was the same as that of Example 1.

[0037] 3. Comparative Example 3 (Environmentally friendly modified pressure-sensitive tape for substrate only): The traditional petroleum-based pressure-sensitive adhesive layer formulation was used. The substrate was the polylactic acid film of Example 1 of this invention, and the release layer was a solvent-based silicone release agent. The preparation process was the same as that of Example 1.

[0038] Comparative analysis and optimization analysis of performance results in the comparative examples and embodiments: 1. Environmental performance comparison and analysis, the specific performance results are shown in Table 2.

[0039] Table 2 Environmental performance results of each embodiment and comparative example

[0040] As can be seen from the data in Table 2, Examples 1-3 of the present invention achieve environmental protection for all components of the adhesive layer, substrate, and release layer. The bio-based monomer and degradable crosslinking agent endow the adhesive layer with degradability, the polylactic acid / polycaprolactone substrate can be completely biodegraded, and the water-based organosilicon release agent has no residual pollution. Therefore, the composting degradation rate reaches more than 82% in 6 months.

[0041] Comparative Example 1 has a degradation rate of only 12% because all components are non-degradable; Comparative Examples 2 and 3 only involve environmental modification in a single step, resulting in degradation rates of only 35%-40%.

[0042] 2. Comparative analysis of adhesive performance, the specific performance results are shown in Table 3.

[0043] Table 3. Adhesion performance results of each embodiment and comparative example.

[0044] As can be seen from the data in Table 3, the present invention, through the reasonable ratio of bio-based soft monomers (isooctyl acrylate / butyl acrylate) and hard monomers (methyl acrylate / ethyl acrylate), combined with biodegradable monomers and biodegradable crosslinking agents, forms a moderately crosslinked network in the adhesive layer, taking into account initial tack, holding power and peel strength. All indicators are comparable to those of traditional petroleum-based tapes (Comparative Example 1), meeting the needs of practical applications.

[0045] Comparative Example 2 uses a polypropylene substrate, which has insufficient adhesion to the environmentally friendly adhesive layer, resulting in a decrease in holding power and peel strength. Comparative Example 3 uses a petroleum-based adhesive layer with poor compatibility with the polylactic acid substrate, making the adhesive layer easy to fall off and significantly reducing the bonding performance.

[0046] Summarize: 1. This invention optimizes the entire chain of environmental protection: it breaks through the limitations of traditional environmentally friendly tapes that modify only one link, and achieves full-component environmental protection from raw material monomers and crosslinking agents to substrates and release agents, solving the industry pain point that "environmental protection and performance cannot be achieved at the same time".

[0047] 2. Performance Synergistic Balance: By controlling the ratio of polymer monomers and the crosslinking process, a high degradation rate is achieved while ensuring that the adhesive performance is on par with traditional tapes, making it a valuable industrial substitute.

[0048] 3. The highly environmentally friendly pressure-sensitive tape of the present invention has a simple preparation process, widely available raw materials, and can be industrialized on a large scale. Moreover, the product has both excellent adhesion and environmental protection properties, and can replace traditional non-environmentally friendly pressure-sensitive tapes, with broad application prospects.

[0049] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A highly environmentally friendly pressure-sensitive adhesive tape, characterized in that, It consists of an environmentally friendly acrylic pressure-sensitive adhesive layer, a biodegradable substrate layer, and an environmentally friendly release layer, which are sequentially laminated. The environmentally friendly acrylic pressure-sensitive adhesive layer comprises the following components in parts by weight: 40-60 parts of bio-based acrylate soft monomers, 10-20 parts of bio-based acrylate hard monomers, 5-10 parts of functional monomers, 0.05-0.5 parts of biodegradable monomers, 1-3 parts of biodegradable crosslinking agents, 0.3-0.8 parts of initiators, and 1-3 parts of photoinitiators.

2. The highly environmentally friendly pressure-sensitive tape according to claim 1, characterized in that: The bio-based acrylate soft monomer is at least one of bio-based isooctyl acrylate and bio-based butyl acrylate; the bio-based acrylate hard monomer is at least one of bio-based methyl acrylate and bio-based ethyl acrylate.

3. The highly environmentally friendly pressure-sensitive tape according to claim 1, characterized in that: The functional monomer is at least one of acrylic acid, methacrylic acid, and acrylamide; the biodegradable crosslinking agent is at least one of triallyl citrate and polylactic acid diacrylate; the biodegradable monomer is at least one of allyl sulfone compound I and allyl sulfone compound II of the following formula; 。 4. The highly environmentally friendly pressure-sensitive tape according to claim 1, characterized in that: The initiator is at least one of azobisisobutyronitrile and benzoyl peroxide.

5. The highly environmentally friendly pressure-sensitive tape according to claim 1, characterized in that: The biodegradable substrate layer is made of one of polylactic acid, polycaprolactone, or polyhydroxyalkanoate, and the thickness of the biodegradable substrate layer is 10-50 μm.

6. The highly environmentally friendly pressure-sensitive tape according to claim 1, characterized in that: The environmentally friendly release layer is a water-based silicone release agent coating layer, and the thickness of the environmentally friendly release layer is 0.1-1.2μm.

7. A method for preparing a highly environmentally friendly pressure-sensitive adhesive tape, used to prepare any one of the highly environmentally friendly pressure-sensitive adhesive tapes as described in claims 1-6, characterized in that, Includes the following steps: S1, Preparation of environmentally friendly acrylic pressure-sensitive adhesive: Nitrogen gas is introduced for 30 minutes before the reaction to remove oxygen from the system, and subsequent reactions are carried out under a nitrogen atmosphere; bio-based soft acrylic monomers, bio-based hard acrylic monomers, biodegradable monomers, initiators, and functional monomers are premixed and added to the reactor to prepare a premixed solution. Stirring is started, and the mixed solvent in the reactor is heated to 65-70℃ and kept at a constant temperature for 2 hours to obtain the prepolymer; Cool the system to below 40°C, add 0.01-0.03 parts of MEHQ polymerization inhibitor, and stir thoroughly; then add the biodegradable crosslinking agent and photoinitiator under light-protected conditions, mix evenly, and filter through a filter with a mesh size of 100 or higher; the resulting environmentally friendly acrylic pressure-sensitive adhesive liquid is obtained. S2, tape composite molding, involves coating a layer of water-based silicone release agent onto the surface of one side of the biodegradable substrate layer using slit extrusion coating or anilox roller coating; then drying it in an oven at 80-100℃ for 3-5 minutes to form an environmentally friendly release layer with a thickness of 0.1-1.2μm. The pressure-sensitive adhesive liquid obtained in step S1 is uniformly coated on the side of the biodegradable substrate layer that is not coated with the release layer by means of comma doctor blade coating or microgravure coating. Then, it is cured by irradiation with an LED UV light source with a wavelength of 365-395nm and an intensity of 80-120mW / cm² for 30-60 seconds. After curing, it is naturally cooled to room temperature to form a pressure-sensitive adhesive layer with a uniform surface and a thickness of 20-40μm. The composite tape material is cured at room temperature for 24-48 hours to stabilize the pressure-sensitive adhesive properties; finally, it is cut to the required width and wound up to obtain the finished tape.

8. The method for preparing a highly environmentally friendly pressure-sensitive adhesive tape according to claim 7, characterized in that: In step S2, the curing process uses UV curing.

9. A highly environmentally friendly pressure-sensitive tape according to claims 1-6, characterized in that: The tape is used in communication equipment, display devices, packaging sealing, fixing and covering electronic components, medical breathable tape, and stationery pasting.

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