Pressure-sensitive adhesive capable of actively extinguishing fire, pressure-sensitive adhesive tape and preparation method of pressure-sensitive adhesive and pressure-sensitive adhesive tape

Abstract

The invention relates to an active fire extinguishing pressure-sensitive adhesive, a pressure-sensitive adhesive tape and a preparation method thereof, and belongs to the technical field of pressure-sensitive adhesive tape preparation. The pressure-sensitive adhesive tape comprises a base material layer and a pressure-sensitive adhesive layer located on at least one side of the base material layer, and the pressure-sensitive adhesive layer comprises a prepolymer, a cross-linking agent, a photoinitiator, a halogen-free flame retardant and a fire extinguishing microcapsule; wherein the prepolymer is obtained by polymerizing two or more than two monomers containing double bonds, the monomers containing double bonds are selected from allyl monomers and / or vinyl monomers, the size of the fire extinguishing microcapsule is 20-1000 microns, and the embedding rate is 10-90%. The novel pressure-sensitive adhesive is obtained by adding the fire extinguishing microcapsules into the adhesive layer and adaptively adjusting the formula, and the used glue is free of VOC, environmentally friendly, formed through light curing and free of high temperature, does not cause early release of the fire extinguishing agent microcapsules, can achieve the effect of efficient fire extinguishing, and keeps high adhesive strength at the same time.

Description

Technical Field

[0001] This invention relates to the field of pressure-sensitive adhesive tape preparation technology, and in particular to an active fire extinguishing pressure-sensitive adhesive, pressure-sensitive adhesive tape, and its preparation method. Background Technology

[0002] Pressure-sensitive adhesive tape (PSA tape) is a flexible, strip-shaped material that is "pressure-sensitive." It bonds instantly with just a light pressure, requiring no water, solvents, or heating. The tape's adhesive strength increases with external pressure, and it generally does not contaminate the bonded surface after peeling. It can be repeatedly applied and removed. The basic structure of PSA tape includes a pressure-sensitive adhesive layer, a substrate, a primer, and a release layer. The pressure-sensitive adhesive layer determines the tack and re-peelability, the substrate provides strength and dimensional stability, the primer enhances the adhesion between the adhesive layer and the substrate, and the release layer prevents the tape from sticking together during winding, ensuring smooth unfolding. Common adhesive systems include acrylic, rubber, silicone, and polyurethane systems.

[0003] Due to their characteristics, pressure-sensitive tapes have wide applications in industry, packaging, and healthcare. In certain specific applications, fire-retardant properties are crucial for pressure-sensitive tapes. For example, in equipment operating at high temperatures or in environments where fire is a potential hazard, using fire-retardant pressure-sensitive tapes can improve safety, prevent fires, or slow their spread. Therefore, flame-retardant pressure-sensitive tapes are particularly suitable for applications such as automotive wiring, wire wrapping, and insulation protection.

[0004] Currently, flame-retardant pressure-sensitive tapes achieve their flame-retardant effect by adding flame retardants to the adhesive or by using a flame-retardant substrate. This only achieves self-flammability and does not support combustion, thus failing to provide active fire protection. The latest active fire protection technology uses fire-extinguishing microcapsules. However, applying this to tape production can be problematic because solvent-based tapes typically require oven drying of the solvent, which can prematurely activate the fire-extinguishing microcapsules, affecting practical use. Therefore, this invention is proposed. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a pressure-sensitive adhesive tape capable of actively extinguishing fires.

[0006] The first objective of this invention is to provide a pressure-sensitive adhesive tape comprising a substrate layer and a pressure-sensitive adhesive layer located on at least one side of the substrate layer; the pressure-sensitive adhesive layer comprises: a prepolymer, a crosslinking agent, a photoinitiator, a halogen-free flame retardant, and fire-extinguishing microcapsules; wherein:

[0007] The prepolymer is obtained by polymerization of two or more monomers containing double bonds;

[0008] The fire extinguishing microcapsules have a size of 20-1000 μm (preferably 50-100 μm) and an encapsulation rate of 10-90% (preferably 50-70%).

[0009] Furthermore, the pressure-sensitive adhesive tape also includes a release film layer located on at least one side of the substrate layer, and on one side, the pressure-sensitive adhesive layer is located between the substrate layer and the release film layer. That is, the pressure-sensitive adhesive tape of the present invention can be a single-sided pressure-sensitive adhesive tape structure or a double-sided pressure-sensitive adhesive tape structure. A single-sided pressure-sensitive adhesive tape structure sequentially includes: a substrate layer, a pressure-sensitive adhesive layer, and a release film layer; a double-sided pressure-sensitive adhesive tape structure sequentially includes: a release film layer, a pressure-sensitive adhesive layer, a substrate layer, a pressure-sensitive adhesive layer, and a release film layer.

[0010] Furthermore, the materials of the substrate layer include, but are not limited to, PET, PI, PA, PU, ​​fiberglass cloth, paper-based, cloth-based, PVC, PO, etc.

[0011] Furthermore, the thickness of the substrate layer is 10-1000 μm.

[0012] Furthermore, the thickness of the pressure-sensitive adhesive layer is 50-1000 μm.

[0013] Furthermore, the thickness of the release film layer is 25-100 μm.

[0014] Furthermore, the release film layer can be made of transparent PET release film.

[0015] Furthermore, the double-bonded monomer is selected from propylene monomers and / or vinyl monomers.

[0016] Further, the propylene-based monomers are selected from acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, sec-butyl acrylate, sec-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, pentyl acrylate, pentyl methacrylate, neopentyl acrylate, neopentyl methacrylate, hexyl acrylate, hexyl methacrylate, heptyl acrylate, heptyl methacrylate, octyl acrylate, octyl methacrylate, isooctyl acrylate, isooctyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, nonyl acrylate, nonyl methacrylate, decyl acrylate, decyl methacrylate, isodecyl acrylate, isodecyl methacrylate, decaacrylate, etc. Monoalkyl esters, undecyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, stearyl acrylate, stearyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, isobornyl acrylate, isobornyl methacrylate, acrylonitrile, acrylamide, methacrylamide, acryloylmorpholine, cyclohexyl acrylate, cyclohexyl methacrylate, tetrahydrofuran acrylate, 2-phenoxyethyl acrylate, dimethylaminoethyl methacrylate, ethoxyethoxyethyl acrylate, dimethacrylamide, glycidyl methacrylate, any one or a combination of at least two of these.

[0017] Furthermore, the vinyl monomer is selected from any one or a combination of at least two of styrene, N-vinylcaprolactam, N-vinylpyrrolidone, or vinyl acetate.

[0018] Furthermore, the prepolymer is obtained by polymerization of monomers from any combination of the following:

[0019] (1) Isooctyl acrylate and acrylic acid;

[0020] (2) n-Butyl acrylate, hydroxybutyl acrylate, and acrylic acid;

[0021] (3) Decyl acrylate, hydroxyethyl acrylate, and acrylic acid;

[0022] (4) n-Butyl acrylate, hydroxypropyl acrylate and N-vinylpyrrolidone.

[0023] Further, by weight, the pressure-sensitive adhesive layer comprises: 100 parts of prepolymer, 0.01-1 parts of crosslinking agent, 0.1-3 parts of photoinitiator, 10-30 parts of halogen-free flame retardant, and 10-100 parts of fire extinguishing microcapsules.

[0024] Further, the monomers in the prepolymer, by weight, are:

[0025] (1) 60-90 parts of isooctyl acrylate and 10-40 parts of acrylic acid;

[0026] (2) 50-70 parts of n-butyl acrylate, 10-30 parts of hydroxybutyl acrylate and 10-20 parts of acrylic acid;

[0027] (3) 40-60 parts of decyl acrylate, 20-40 parts of hydroxyethyl acrylate and 10-20 parts of acrylic acid;

[0028] (4) 40-60 parts of n-butyl acrylate, 20-40 parts of hydroxypropyl acrylate and 10-20 parts of N-vinylpyrrolidone.

[0029] Furthermore, the crosslinking agent is selected from one or more of the following: trimethylolpropane triacrylate, pentaerythritol triacrylate, tri(2-hydroxyethyl)isocyanurate triacrylate, dipentaerythritol tetraacrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, and dipentaerythritol hexaacrylate.

[0030] Furthermore, the photoinitiator is selected from one or more of α,α-dimethoxy-α-phenylacetophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl methyl ketone, benzophenone, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-hydroxy-1-(4-(2-hydroxy-2-methylpropionylphenyl)benzyl)-2-methyl-1-propanone, and macromolecular photoinitiators such as thioxanthones.

[0031] Furthermore, the halogen-free flame retardant is any one or a mixture of at least two of the following: phosphorus-based flame retardants, nitrogen-based flame retardants, silicon-based flame retardants, metal hydroxide flame retardants, metal oxide flame retardants, flame-retardant acrylic resins, and metal boride flame retardants.

[0032] Furthermore, the fire extinguishing microcapsule has a core-shell structure. The core material includes at least one selected from perfluorohexanone, perfluorohexane, perfluoroheptane, perfluorooctane, tetrafluorodibromoethane, or trifluorotrichloroethane. The shell material is a polymer material, including at least one selected from polystyrene, polymethyl methacrylate, polycaprolactone, and acrylonitrile-butadiene-styrene copolymer. Preferably, the microcapsule fire extinguishing agent is purchased from Hefei Zhongke Chuangwei Technology Co., Ltd.

[0033] Furthermore, the preparation method of the prepolymer includes: mixing two or more monomers containing double bonds with a photoinitiator in an inert gas atmosphere, and irradiating with (ultraviolet) light to obtain the prepolymer.

[0034] The second objective of this invention is to provide a method for preparing the pressure-sensitive adhesive tape, comprising the following steps: weighing each component according to the formula, stirring evenly under vacuum conditions to obtain an adhesive, applying the adhesive between the substrate layer and the release film layer, and photocuring to obtain the pressure-sensitive adhesive tape.

[0035] A third object of the present invention is to provide a composition for preparing pressure-sensitive adhesives, wherein, by weight, the composition comprises: 100 parts of prepolymer, 0.01-1 parts of crosslinking agent, 0.1-3 parts of photoinitiator, 10-30 parts of halogen-free flame retardant, and 10-100 parts of fire extinguishing microcapsules; wherein:

[0036] The prepolymer is obtained by polymerization of two or more monomers containing double bonds;

[0037] The fire extinguishing microcapsules have a size of 20-1000 μm and an encapsulation rate of 10-90%.

[0038] A fourth object of the present invention is to provide the application of the pressure-sensitive tape or composition in the preparation of fire-retardant materials.

[0039] Compared with the prior art, the above-described technical solution of the present invention has the following advantages:

[0040] This invention, by adding fire-extinguishing microcapsules to the adhesive layer and adaptively adjusting the formulation, yields a novel pressure-sensitive adhesive and tape. The adhesive used in this pressure-sensitive adhesive is VOC-free, environmentally friendly, light-cured, and does not require high temperatures, thus preventing premature release of the fire-extinguishing agent microcapsules. The fire-extinguishing microcapsules have a destructive temperature above 90°C and are themselves flame-retardant. The pressure-sensitive tape provided by this invention achieves highly efficient fire extinguishing while maintaining high adhesion, and can be applied to bonding applications in enclosed spaces such as electrical control boxes, power switches, servers, and battery packs. Detailed Implementation

[0041] The present invention will be further described below with reference to specific embodiments, so that those skilled in the art can better understand and implement the present invention, but the embodiments are not intended to limit the present invention.

[0042] The materials involved in this invention are as follows:

[0043] Fire extinguishing agent microcapsules: purchased from Hefei Zhongke Chuangwei Technology Co., Ltd.

[0044] Example 1

[0045] Preparation of prepolymers obtained from the polymerization of monomers containing double bonds:

[0046] 90 parts of isooctyl acrylate, 10 parts of acrylic acid, and 0.05 parts of α,α-dimethoxy-α-phenylacetophenone were placed in a three-necked flask and stirred for 30 minutes under a nitrogen atmosphere. The prepolymerization reaction was carried out by irradiation with a 365nm LED ultraviolet lamp to obtain an acrylate prepolymer solution with a viscosity of 1000~10000 CPS.

[0047] Pressure-sensitive adhesive layer preparation:

[0048] 100 parts of the prepolymer obtained by polymerization of the above-mentioned monomers containing double bonds, 0.2 parts of α,α-dimethoxy-α-phenylacetophenone, 0.05 parts of 1,6-hexanediol diacrylate, 20 parts of phosphorus-based flame retardant Clariant OP935, and 50 parts of fire extinguishing agent microcapsules with a particle size of 50 μm and an encapsulation rate of 50% were placed in a mixing tank and vacuum stirred for 1 hour at a speed of 100 RPM to obtain a pressure-sensitive adhesive layer.

[0049] Made of tape:

[0050] A pressure-sensitive adhesive layer of 100µm was applied between 100µm PET and 50µm PET release films using a dual-roller coating head. The layer was then cured using 365nm UV light on both sides to obtain a single-sided pressure-sensitive adhesive tape with a total thickness of 200µm. The curing energy was 100mW per side and 1500mJ / cm² for the total curing energy. All examples and comparative examples are illustrated using this structure.

[0051] Example 2

[0052] Replace 90 parts of isooctyl acrylate and 10 parts of acrylic acid with 70 parts of n-butyl acrylate, 20 parts of hydroxybutyl acrylate and 10 parts of acrylic acid, and the rest are the same as in Example 1.

[0053] Example 3

[0054] Replace 90 parts of isooctyl acrylate and 10 parts of acrylic acid with 60 parts of decyl acrylate, 30 parts of hydroxyethyl acrylate and 10 parts of acrylic acid, and the rest are the same as in Example 1.

[0055] Example 4

[0056] 90 parts of isooctyl acrylate and 10 parts of acrylic acid were replaced with 50 parts of n-butyl acrylate, 30 parts of hydroxypropyl acrylate and 20 parts of N-vinylpyrrolidone, and the rest were the same as in Example 1 and Example 3.

[0057] Example 5

[0058] The crosslinking agent 1,6-hexanediol diacrylate was replaced with pentaerythritol triacrylate, and the rest was the same as in Example 3.

[0059] Comparative Example 1

[0060] No fire extinguishing agent microcapsules were added; otherwise, the process was the same as in Example 3.

[0061] Comparative Example 2

[0062] The fire extinguishing agent microcapsules were replaced with perfluorohexanone, and the rest was the same as in Example 3.

[0063] Comparative Example 3

[0064] Replace 0.05 parts of 1,6-hexanediol diacrylate with 5 parts of 1,6-hexanediol diacrylate, and the rest is the same as in Example 3.

[0065] Test case

[0066] All products prepared in the examples and comparative examples were tested for steel sheet peel force, static shear strength of mirror-finished steel sheet, and flame retardancy, wherein:

[0067] Peel strength test conditions for steel plates: 90° peel strength, placed at room temperature for 72 hours, standard ASTM D3330 N / cm;

[0068] Static shear strength of mirror-finished steel plates: Refer to GB / T 4851-1998.

[0069] Flame retardancy test: Refer to UL94-2023.

[0070] Active fire extinguishing capability: Place an alcohol lamp at the bottom of a 20L sealed container, light it, remove the release film from both sides of a 100mm*100mm tape, place it above the alcohol lamp at a distance of 10-20mm, and observe whether the alcohol lamp goes out within 30 seconds.

[0071] The test results are shown in the table below.

[0072] Table 1 Test Results

[0073]

[0074] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A pressure-sensitive adhesive tape, characterized in that, The pressure-sensitive adhesive tape includes a substrate layer and a pressure-sensitive adhesive layer located on at least one side of the substrate layer; the pressure-sensitive adhesive layer comprises: a prepolymer, a crosslinking agent, a photoinitiator, a halogen-free flame retardant, and fire extinguishing microcapsules; wherein: The prepolymer is obtained by polymerization of two or more monomers containing double bonds; The fire extinguishing microcapsules have a size of 20-1000 μm and an encapsulation rate of 10-90%.

2. The pressure-sensitive tape according to claim 1, characterized in that, The pressure-sensitive adhesive tape further includes a release film layer located on at least one side of the substrate layer, and contains at least one of the following features: (1) On one side, the pressure-sensitive adhesive layer is located between the substrate layer and the release film layer; (2) The thickness of the release film is 25-100 μm; (3) The material of the release film includes PET.

3. The pressure-sensitive tape according to claim 1, characterized in that, It must contain at least one of the following characteristics: (1) The material of the substrate layer includes PET, PI, PA, PU, ​​fiberglass cloth, paper-based, cloth-based, PVC or PO; (2) The thickness of the substrate layer is 10-1000 μm; (3) The thickness of the pressure-sensitive adhesive layer is 50-1000 μm.

4. The pressure-sensitive tape according to claim 1, characterized in that, The double-bonded monomer is selected from propylene monomers and / or vinyl monomers, wherein: The propylene-based monomers are selected from acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, sec-butyl acrylate, sec-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, pentyl acrylate, pentyl methacrylate, neopentyl acrylate, neopentyl methacrylate, hexyl acrylate, hexyl methacrylate, heptyl acrylate, heptyl methacrylate, octyl acrylate, octyl methacrylate, isooctyl acrylate, isooctyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, nonyl acrylate, nonyl methacrylate, decyl acrylate, decyl methacrylate, isodecyl methacrylate, isodecyl methacrylate, undecane acrylate. The following are all compounds: undecyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, stearyl acrylate, stearyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, isobornyl acrylate, isobornyl methacrylate, acrylonitrile, acrylamide, methacrylamide, acryloylmorpholine, cyclohexyl acrylate, cyclohexyl methacrylate, tetrahydrofuran acrylate, 2-phenoxyethyl acrylate, dimethylaminoethyl methacrylate, ethoxyethoxyethyl acrylate, dimethacrylamide, glycidyl methacrylate; And / or, the vinyl monomers are selected from any one or a combination of at least two of styrene, N-vinylcaprolactam, N-vinylpyrrolidone or vinyl acetate.

5. The pressure-sensitive tape according to claim 1, characterized in that, It must contain at least one of the following characteristics: (1) The prepolymer is obtained by polymerization of monomers in any combination of the following: I. Isooctyl acrylate and acrylic acid; II. n-Butyl acrylate, hydroxybutyl acrylate, and acrylic acid; III. Decyl acrylate, hydroxyethyl acrylate, and acrylic acid; IV. n-Butyl acrylate, hydroxypropyl acrylate, and N-vinylpyrrolidone; (2) The preparation method of the prepolymer includes: mixing two or more monomers containing double bonds with a photoinitiator in an inert gas atmosphere, and irradiating with light to obtain the prepolymer.

6. The pressure-sensitive tape according to claim 1 or 5, characterized in that, It must contain at least one of the following characteristics: (1) By weight, the pressure-sensitive adhesive layer comprises: 100 parts of prepolymer, 0.01-1 parts of crosslinking agent, 0.1-3 parts of photoinitiator, 10-30 parts of halogen-free flame retardant and 10-100 parts of fire extinguishing microcapsules; (2) By weight, the monomer in the prepolymer is any one of the following: I. 60-90 parts of isooctyl acrylate and 10-40 parts of acrylic acid; II. 50-70 parts of n-butyl acrylate, 10-30 parts of hydroxybutyl acrylate and 10-20 parts of acrylic acid; III. 40-60 parts of decyl acrylate, 20-40 parts of hydroxyethyl acrylate and 10-20 parts of acrylic acid; IV. 40-60 parts of n-butyl acrylate, 20-40 parts of hydroxypropyl acrylate, and 10-20 parts of N-vinylpyrrolidone.

7. The pressure-sensitive tape according to claim 1, characterized in that, It must contain at least one of the following characteristics: (1) The crosslinking agent is selected from one or more of the following: trimethylolpropane triacrylate, pentaerythritol triacrylate, tri(2-hydroxyethyl)isocyanurate triacrylate, dipentaerythritol tetraacrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, and dipentaerythritol hexaacrylate. (2) The photoinitiator is selected from one or more of α,α-dimethoxy-α-phenylacetophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl methyl ketone, benzophenone, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-hydroxy-1-(4-(2-hydroxy-2-methylpropionylphenyl)benzyl)-2-methyl-1-propanone, and macromolecular photoinitiators such as thioxanthones; (3) The halogen-free flame retardant is any one or a mixture of at least two of the following: phosphorus-based flame retardant, nitrogen-based flame retardant, silicon-based flame retardant, metal hydroxide flame retardant, metal oxide flame retardant, flame-retardant acrylic resin, and metal boride flame retardant; (4) The fire extinguishing microcapsule has a core-shell structure. The core material includes at least one of perfluorohexanone, perfluorohexane, perfluoroheptane, perfluorooctane, tetrafluorodibromoethane or trifluorotrichloroethane, and the shell material includes at least one of polystyrene, polymethyl methacrylate, polycaprolactone, acrylonitrile-butadiene-styrene copolymer.

8. The method for preparing the pressure-sensitive adhesive tape according to any one of claims 1-7, characterized in that, The process includes the following steps: weighing each component according to the formula, stirring them evenly under vacuum to obtain an adhesive, applying the adhesive to at least one side of the substrate layer, and photocuring to obtain the pressure-sensitive tape.

9. A composition for preparing pressure-sensitive adhesive, characterized in that, By weight, the composition comprises: 100 parts prepolymer, 0.01-1 parts crosslinking agent, 0.1-3 parts photoinitiator, 10-30 parts halogen-free flame retardant, and 10-100 parts fire extinguishing microcapsules; wherein: The prepolymer is obtained by polymerization of two or more monomers containing double bonds; The fire extinguishing microcapsules have a size of 20-1000 μm and an encapsulation rate of 10-90%.

10. The use of the pressure-sensitive tape according to any one of claims 1-7, the pressure-sensitive tape prepared by the preparation method according to claim 8, or the composition according to claim 9 in the preparation of fire-retardant materials.

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