Flame-retardant PVC adhesive tape and preparation method thereof
Through innovative combination of materials and processes, the flame-retardant PVC tape produced achieves a balance between high performance and low cost. It has excellent flame retardant, conductive and adhesive properties, meeting the needs of most industrial scenarios and reducing raw material costs and carbon emissions.
Patent Information
- Application Number
- CN202511166413.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-20
- Publication Date
- 2025-10-10
AI Technical Summary
Existing tape technology cannot achieve both high performance and low cost. High-performance tape relies on expensive raw materials and complex processes, resulting in excessively high unit prices, while the key performance of low-cost tape is difficult to meet high-end needs.
The flame-retardant isolation layer is formed by the hybridization of phosphazene compounds and layered silicates, the dynamic cross-linking layer is a graft copolymer formed by the Diels-Alder reaction of epichlorohydrin rubber and PVC, the conductive reinforcement layer is a core-shell structure composite fiber composed of carbon nanotubes and polyaniline, and the bio-based adhesive layer contains rosin derivatives and epoxy soybean oil acrylate. It is prepared by supercritical CO2 treatment, multi-temperature zone co-extrusion die synchronous extrusion and UV curing.
It achieves a balance between UL94 V-0 flame retardancy and volume resistivity, has stable peel strength, high retention rate after aging, high shear strength retention rate of the dynamic cross-linking layer at high temperature, excellent shielding effectiveness of the carbon nanotube/graphene conductive layer, high raw material recycling rate, and reduces costs and carbon emissions.
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Figure CN120758186A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of PVC tapes, in particular to a flame-retardant PVC tape and a preparation method thereof. Background Art
[0002] Functional tape is a key auxiliary material in modern industry. Its performance directly affects the safety and reliability of electronic equipment, vehicles and infrastructure. With technological advancement, the application scenarios of tape continue to expand, and the requirements for material performance are becoming increasingly stringent.
[0003] For example, power battery packs in the new energy sector require tapes that meet the requirements of fire protection, electromagnetic shielding, and electrolyte corrosion resistance; cable fixing tapes for aerospace applications need to maintain bonding strength under temperature differences of -60°C to 200°C and avoid signal interference; fire-resistant sealing tapes for green buildings need to pass environmental certification and adapt to long-term sun aging.
[0004] Current mainstream tape technologies, such as single-layer flame-retardant EVA tape and co-extruded PVC tape, have the problem of not being able to strike a balance between high performance and low cost. Specifically, high-performance tapes rely on expensive raw materials and complex processes, resulting in excessively high unit prices, while the key performance of low-cost tapes only meets basic standards and is difficult to meet high-end needs. Summary of the Invention
[0005] The object of the present invention is to provide a flame retardant PVC tape and a preparation method thereof, so as to solve the problems raised in the above background technology.
[0006] To achieve the above object, the present invention provides the following technical solutions:
[0007] A flame retardant PVC tape, comprising, from outside to inside:
[0008] A flame retardant isolation layer formed by hybridization of a phosphazene compound and a layered silicate;
[0009] a dynamically cross-linked layer comprising a graft copolymer of epichlorohydrin rubber and PVC formed by a Diels-Alder reaction;
[0010] The conductive reinforcement layer is composed of a core-shell structure composite fiber composed of carbon nanotubes and polyaniline;
[0011] Bio-based adhesive layer containing rosin derivatives and epoxidized soybean oil acrylate.
[0012] In the present invention, the phosphazene compound in the flame retardant isolation layer is hexaphenoxycyclotriphosphazene or hexachlorocyclotriphosphazene, the layered silicate is sodium montmorillonite or lithium montmorillonite, and the mass ratio of the phosphazene compound to the layered silicate is 1:1 to 1:5.
[0013] In the present invention, the thickness of the flame retardant isolation layer is 5 μm to 8 μm, and the limiting oxygen index is ≥32%.
[0014] In the present invention, the dynamic crosslinking layer is prepared from the following raw materials in parts by weight:
[0015] 100 parts of PVC resin;
[0016] 15 to 25 parts of epichlorohydrin rubber;
[0017] 3 to 8 parts of furan-functionalized maleic anhydride;
[0018] 0.05 to 0.2 parts of catalyst.
[0019] In the present invention, the catalyst is dibutyltin dilaurate or stannous octoate, and the dynamic cross-linking layer has a storage modulus retention rate of ≥85% at 80° C. and an elongation at break of ≥250%.
[0020] In the present invention, the diameter distribution of the core-shell structure composite fiber in the conductive reinforcement layer is 50nm to 80nm, and the surface resistivity is ≤10 6 Ω / sq, and the orientation degree of the composite fibers in the layer is greater than 80%.
[0021] In the present invention, the aspect ratio of the core-shell structure composite fiber is greater than 1000, and the doping rate of the shell polyaniline is 30% to 50%.
[0022] In the present invention, the bio-based adhesive layer further comprises nanocellulose and hydrogenated rosin ester, wherein:
[0023] The average diameter of nanocellulose is 15nm to 25nm, and the addition amount is 1 part to 10 parts;
[0024] The mass ratio of hydrogenated rosin ester to epoxy soybean oil acrylate is 1:2 to 1:5.
[0025] A method for preparing the flame-retardant PVC tape comprises the following steps:
[0026] Step S1, treating the phosphazene compound and the layered silicate under supercritical CO2 conditions, controlling the pressure to 8MPa-12MPa, the temperature to 35°C-45°C, and the treatment time to 1 hour-3 hours;
[0027] Step S2, polymerizing the dynamic crosslinking layer raw material in a microwave reactor in stages, with the first stage being at 60°C ± 5°C for 10 to 20 minutes, and the second stage being at 105°C to 115°C for 20 to 40 minutes;
[0028] Step S3, synchronously extruding the flame retardant isolation layer, the dynamic cross-linking layer and the conductive reinforcement layer through a multi-temperature zone co-extrusion die head;
[0029] Step S4: Apply bio-based adhesive on the surface of the conductive reinforcement layer with UV curing energy of 800 mJ / cm 2 ~1000mJ / cm 2 .
[0030] In the present invention, in step S3, the temperature of the co-extrusion die is controlled as follows:
[0031] The temperature of the flame retardant isolation layer is 145℃~155℃;
[0032] The temperature of the dynamic cross-linking layer is 130°C to 140°C;
[0033] The temperature of the conductive reinforcement layer area is 115°C to 125°C;
[0034] The thickness ratio of each layer is 1:0.8:0.5.
[0035] Compared with the prior art, the present invention has the following beneficial effects:
[0036] 1. The present invention achieves a balance between UL94 V-0 flame retardancy and volume resistivity through a combination of conventional raw materials, meeting the needs of most industrial scenarios. The peel strength is stable at 6.5 to 8.0 N / cm, and the retention rate after aging is ≥ 65%;
[0037] 2. The dynamic cross-linking layer of the present invention has a shear strength retention rate of >80% at 200°C, and the carbon nanotube / graphene conductive layer enables the shielding effectiveness to reach 65dB, far exceeding military standards;
[0038] 3. The recycled materials in the present invention account for more than 50%, reducing raw material costs by 39.5% and carbon emissions by 22%. BRIEF DESCRIPTION OF THE DRAWINGS
[0039] Figure 1 The overall process flow chart for preparing the adhesive tape of the present invention is as follows;
[0040] Figure 2 It is a step-by-step process diagram of the present invention;
[0041] Figure 3 This is a flow chart of recycled material processing according to the present invention. DETAILED DESCRIPTION
[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.
[0043] Example 1
[0044] The steps for preparing the flame retardant isolation layer are as follows:
[0045] First, 100 g of hexachlorocyclotriphosphazene was mixed with 300 g of sodium montmorillonite, placed in a supercritical CO2 reactor, and treated at 10 MPa and 40°C for 2 hours, during which 500 W ultrasonic assisted dispersion was applied to obtain an off-white powdery hybrid material.
[0046] The preparation steps of the dynamic cross-linking layer are as follows:
[0047] First, 100 kg of PVC resin (degree of polymerization 1300), 20 kg of chloroether rubber (brand GECO 3430), 5 kg of furan-functionalized maleic anhydride, and 0.1 kg of dibutyltin dilaurate were added to an internal mixer and mixed at 65°C for 15 minutes. The mixture was then heated to 110°C and reacted for 30 minutes to obtain a light yellow elastomeric compound.
[0048] The steps for preparing the conductive reinforcement layer are as follows:
[0049] First, multi-walled carbon nanotubes (20 nm in diameter and 50 μm in length) were dispersed in a 0.3 mol / L aniline hydrochloride solution, and 1.2 times the molar amount of ammonium persulfate of aniline was added. The mixture was then reacted at 2°C for 8 hours. The fibers collected by centrifugation were examined by scanning electron microscopy and showed an average diameter of 65 ± 5 nm, a polyaniline coating thickness of 8 to 12 nm, and a surface resistivity of 5 × 10 5 Ω / sq.
[0050] The steps for preparing the bio-based adhesive layer are as follows:
[0051] 15 kg of hydrogenated rosin ester (softening point 78°C), 45 kg of epoxidized soybean oil acrylate (functionality 3.2), 5 kg of nanocellulose (diameter 20 nm, length 1 μm), and 0.5 kg of benzophenone photoinitiator were mixed and stirred at 50°C for degassing. The viscosity was measured to be 8500±500 cps (25°C).
[0052] like Figure 1 As shown, the steps of tape forming are as follows:
[0053] A five-layer co-extrusion production line was used, and the flame retardant isolation layer extruder was set at 150°C and the screw speed was 25 rpm; the dynamic cross-linking layer extruder was set at 135°C and the screw speed was 30 rpm; the conductive reinforcement layer extruder was set at 120°C and the screw speed was 20 rpm. The die head temperature was controlled at 155°C / 140°C / 125°C. Before winding, a bio-based adhesive (wet film thickness 50 μm) was applied to the surface of the conductive reinforcement layer. UV curing was performed using a mercury lamp (dominant wavelength 365 nm, energy density 900 mJ / cm 2 ).
[0054] In this embodiment, the UL94 V-0 flame retardant grade (1.0 mm thickness) and volume resistivity (10 8 The peel strength is stable at 6.5-8.0 N / cm (on stainless steel substrate), and the retention rate after aging (85°C / 500h) is ≥65%.
[0055] Specifically, single-layer extrusion molding is adopted, the production speed can reach 30m / min, the yield rate is ≥98% (the industry average is 95%), the raw materials do not require special pretreatment, and commercial brands (such as EVA 2805) can be directly purchased.
[0056] Example 2
[0057] 1. Raw material preparation:
[0058] The raw materials of the flame retardant isolation layer include hexaphenoxy cyclotriphosphazene (purity ≥99%, Japan Otsuka Chemical) and lithium montmorillonite (CEC value 110mmol / 100g, Zhejiang Fenghong New Materials).
[0059] The raw materials of the dynamic cross-linking layer include PVC resin (brand S-700, degree of polymerization 1700, Qilu Petrochemical), epichlorohydrin rubber (brand HYDRIN T3100, containing 3.2% epoxy groups, Zeon, USA), furan-functionalized maleic anhydride (homemade, degree of substitution 0.85), and stannous octoate (industrial grade, tin content 28±0.5%).
[0060] The raw materials of the conductive enhancement layer include multi-walled carbon nanotubes (NC7000, diameter 9.5 nm, length 1.5 μm, Nanocyl), aniline (purified by distillation, purity ≥99.5%), and sodium dodecylbenzenesulfonate (analytical grade).
[0061] The raw materials of the bio-based adhesive layer include hydrogenated rosin ester (softening point 82°C, Guangdong Hualin Chemical), epoxidized soybean oil acrylate (double bond content 4.1 mmol / g, Jiangsu Litian Technology), and nanocellulose (diameter 18±2 nm, length 1.2 μm, Canada FPInnovations).
[0062] 2. Preparation of tape:
[0063] The steps for preparing the flame retardant isolation layer are as follows:
[0064] Hexaphenoxycyclotriphosphazene and lithium montmorillonite were mixed in a mass ratio of 1:3, placed in a supercritical CO2 reactor (Nantong Supercritical Equipment, model SCF-50L), and treated at 12 MPa and 45°C for 2.5 hours. After pressure release, a light yellow fluffy material was obtained.
[0065] The preparation steps of the dynamic cross-linking layer are as follows:
[0066] The initial temperature of an internal mixer (Lina Machinery, LN-50) was set at 60°C: 100 kg of PVC resin and 25 kg of epichlorohydrin rubber were mixed for 5 minutes, and 6 kg of furan-functionalized maleic anhydride, 0.15 kg of stannous octoate, and 1 kg of trimethylolpropane triacrylate were added. The temperature was raised to 115°C and the reaction was carried out for 35 minutes. The material was discharged when the torque stabilized at 28 ± 2 N·m.
[0067] The steps for preparing the conductive reinforcement layer are as follows:
[0068] A 0.4 mol / L aniline hydrochloride solution was prepared, 0.1 wt% sodium dodecylbenzenesulfonate was added, multi-walled carbon nanotubes (solid content 1.2%) were dispersed, and ultrasonic treatment was performed (500 W, 30 min). Ammonium persulfate with a molar amount of 1.3 times that of aniline was added, and the reaction was controlled at 3°C in an ice bath for 9 hours. TEM examination of the fibers collected by centrifugation showed that the thickness of the polyaniline shell was 15±2 nm.
[0069] The steps for preparing the bio-based adhesive layer are as follows:
[0070] Hydrogenated rosin ester (20 kg), epoxy soybean oil acrylate (60 kg), nanocellulose (8 kg) and 2-hydroxy-2-methyl-1-phenyl-1-propanone (0.6 kg) were vacuum degassed at 60° C. for 2 hours.
[0071] like Figure 2 As shown, the steps of tape forming are as follows:
[0072] The first stage of lamination (flame retardant layer + cross-linking layer): the flame retardant isolation layer film and the dynamic cross-linking layer sheet are laminated by hot pressing (temperature 130°C, pressure 0.8 MPa, time 30 seconds), and immediately cooled to room temperature after lamination to avoid excessive curing of the cross-linking layer.
[0073] Second stage lamination (adding conductive layer): peel off the PET release film of the conductive reinforcement layer and align it with the cross-linked layer side of the first stage composite. Use roller lamination (roller temperature 70℃, line pressure 50N / mm), and synchronously rewind to remove bubbles.
[0074] The third stage of lamination (adhesive layer bonding): the bio-based adhesive layer and the conductive reinforcement layer are laminated by cold pressing (pressure 0.5 MPa, room temperature for 2 minutes);
[0075] After compounding, UV curing (wavelength 365nm, irradiation 200mJ / cm 2 ).
[0076] In this embodiment, the shear strength retention rate of the dynamically cross-linked layer at 200°C is greater than 80% (compared to only 42% in Example 1), and the carbon nanotube / graphene conductive layer enables a shielding effectiveness of 65dB (1GHz, ASTM D4935), far exceeding the military standard (≥30dB).
[0077] Specifically, the five-layer step-by-step composite process avoids conflicts in material properties (for example, high-temperature processing of the flame-retardant layer does not destroy the conductive layer structure), and the UV-curable bio-based adhesive layer achieves an initial adhesion of 5 seconds (the pressure-sensitive adhesive industry takes an average of 30 seconds).
[0078] Example 3
[0079] 1. Raw material preparation:
[0080] The raw materials of the flame retardant isolation layer include 80% new hexachlorocyclotriphosphazene + 20% recycled material (purified by washing with methanol), and the layered silicate is replaced by calcium-based bentonite (the price is 40% lower than that of montmorillonite).
[0081] The raw materials of the dynamic cross-linking layer include PVC resin mixed with 30% recycled PVC (passing 80 mesh sieve), the amount of epichlorohydrin rubber is reduced to 15kg, and 5kg of nitrile rubber (NBR 2865) is supplemented.
[0082] The conductive reinforcement layer's raw materials include carbon nanotubes replaced with 20% acetylene black (Vulcan XC-72), and polyaniline doping replaced with camphorsulfonic acid (cost reduction of 35%).
[0083] The raw materials of the bio-based adhesive layer include hydrogenated rosin ester completely replaced by disproportionated rosin (model DDR-20), nanocellulose is eliminated and replaced by sodium lignin sulfonate (2kg).
[0084] 2. Preparation of tape:
[0085] The steps for preparing the flame retardant isolation layer are as follows:
[0086] Recovered hexachlorocyclotriphosphazene (80 kg) and calcium bentonite (150 kg) were mixed in batches, and silane coupling agent KH-550 (0.8 kg, diluted with ethanol) was added for spraying and mixed evenly. The mixture was fed into an extruder, melted, kneaded, and then extruded into granules. After granulation, the moisture content of the granules was ensured to be ≤0.15%.
[0087] The preparation steps of the dynamic cross-linking layer are as follows:
[0088] Recycled PVC powder (30 kg) was premixed with calcium stearate (2 kg) for 10 minutes. New PVC material (70 kg) and pretreated recycled material (30 kg) were mixed for 5 minutes. Nitrile rubber (NBR 2865, 5 kg) was added and the mixture was continued to 75°C. Plasticizer DOP (8 kg) and stabilizer Ba / Zn (1.5 kg) were added and the mixture was passed through the mixture 5 times to mix evenly. Finally, crosslinker DCP (0.3 kg) was added and the mixture was triangularly packaged 3 times.
[0089] The steps for preparing the conductive reinforcement layer are as follows:
[0090] Aniline hydrochloride solution (0.25 mol / L, pH = 1.5) was prepared to prepare an acetylene carbon black suspension (2 wt%). The mixture was ultrasonically dispersed for 30 minutes, and aniline monomer was added to control the mass ratio of carbon black to aniline to be 1:0.2. Ammonium persulfate (molar ratio 1:1.2) was added dropwise. The temperature was controlled at 5°C ± 1°C in an ice bath to react for 12 hours. After the reaction was completed, the mixture was filtered and washed three times with 0.1 M HCl.
[0091] The steps for preparing the bio-based adhesive layer are as follows:
[0092] Disproportionated rosin (25 kg), epoxidized soybean oil (10 kg), and sodium lignin sulfonate (5 kg) were mixed, tert-butyl hydroperoxide (0.4 kg) was added, and the mixture was stirred at 80° C. under nitrogen protection for 2 hours. The final viscosity was controlled at 3500±200 cps (25° C.).
[0093] like Figure 3 As shown, the steps of tape forming are as follows:
[0094] The multi-layer co-extrusion process is adopted to extrude the flame retardant layer, cross-linking layer and conductive layer separately.
[0095] After compounding, it was cured by hot air (120℃, 90 seconds) and UV secondary curing (300mJ / cm 2 ).
[0096] In this embodiment, the proportion of recycled materials exceeds 50% (the flame retardant layer uses phosphazene extracted from waste cables, and the cross-linking layer uses waste PVC from doors and windows), which reduces the raw material cost by 39.5% and reduces carbon emissions by 22% compared with Example 1 (CO2 equivalent per square meter 1.8kg vs. 2.3kg).
[0097] Specifically, the co-extrusion process is compatible with existing PVC cable production lines, with low equipment modification costs. The conductive layer uses in-situ polymerization of carbon black / polyaniline, avoiding expensive nanomaterials (such as CNT in Example 2).
[0098] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.
[0099] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.
Claims
1. A flame-retardant PVC tape, characterized by: From outside to inside, it includes: A flame retardant isolation layer formed by hybridization of a phosphazene compound and a layered silicate; a dynamically cross-linked layer comprising a graft copolymer of epichlorohydrin rubber and PVC formed by a Diels-Alder reaction; The conductive reinforcement layer is composed of a core-shell structure composite fiber composed of carbon nanotubes and polyaniline; Bio-based adhesive layer containing rosin derivatives and epoxidized soybean oil acrylate.
2. The flame-retardant PVC tape according to claim 1, characterized in that: The phosphazene compound in the flame retardant isolation layer is hexaphenoxy cyclotriphosphazene or hexachlorocyclotriphosphazene, the layered silicate is sodium montmorillonite or lithium montmorillonite, and the mass ratio of the phosphazene compound to the layered silicate is 1:1 to 1:
5.
3. The flame-retardant PVC tape according to claim 2, characterized in that: The thickness of the flame retardant isolation layer is 5 μm to 8 μm, and the limiting oxygen index is ≥32%.
4. The flame-retardant PVC tape according to claim 1, characterized in that: The dynamic crosslinking layer is prepared from the following raw materials in parts by weight: 100 parts of PVC resin; 15 to 25 parts of epichlorohydrin rubber; 3 to 8 parts of furan-functionalized maleic anhydride; 0.05 to 0.2 parts of catalyst.
5. The flame-retardant PVC tape according to claim 4, characterized in that: The catalyst is dibutyltin dilaurate or stannous octoate, and the dynamic cross-linking layer has a storage modulus retention rate of ≥85% at 80° C. and an elongation at break of ≥250%.
6. The flame-retardant PVC tape according to claim 1, characterized in that: The diameter distribution of the core-shell structure composite fiber in the conductive reinforcement layer is 50nm to 80nm, and the surface resistivity is ≤10 6 Ω / sq, and the orientation degree of the composite fibers in the layer is greater than 80%.
7. The flame-retardant PVC tape according to claim 6, characterized in that: The aspect ratio of the core-shell structure composite fiber is greater than 1000, and the doping rate of the shell polyaniline is 30% to 50%.
8. The flame-retardant PVC tape according to claim 1, characterized in that: The bio-based adhesive layer further comprises nanocellulose and hydrogenated rosin ester, wherein: The average diameter of nanocellulose is 15nm to 25nm, and the addition amount is 1 part to 10 parts; The mass ratio of hydrogenated rosin ester to epoxy soybean oil acrylate is 1:2 to 1:
5.
9. A method for preparing the flame-retardant PVC tape according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step S1, treating the phosphazene compound and the layered silicate under supercritical CO2 conditions, controlling the pressure to 8MPa-12MPa, the temperature to 35°C-45°C, and the treatment time to 1 hour-3 hours; Step S2, polymerizing the dynamic crosslinking layer raw material in a microwave reactor in stages, with the first stage being at 60°C ± 5°C for 10 to 20 minutes, and the second stage being at 105°C to 115°C for 20 to 40 minutes; Step S3, synchronously extruding the flame retardant isolation layer, the dynamic cross-linking layer and the conductive reinforcement layer through a multi-temperature zone co-extrusion die head; Step S4: Apply bio-based adhesive on the surface of the conductive reinforcement layer with UV curing energy of 800 mJ / cm 2 ~1000mJ / cm 2 .
10. The method according to claim 9, characterized in that: In step S3, the temperature of the co-extrusion die is controlled as follows: The temperature of the flame retardant isolation layer is 145℃~155℃; The temperature of the dynamic cross-linking layer is 130°C to 140°C; The temperature of the conductive reinforcement layer area is 115°C to 125°C; The thickness ratio of each layer is 1:0.8:0.5.