Flame-retardant transparent hot-melt pressure-sensitive adhesive, and preparation method therefor and use thereof

Abstract

The present invention relates to a flame-retardant transparent hot-melt pressure-sensitive adhesive, and a preparation method therefor and the use thereof. The flame-retardant transparent hot-melt pressure-sensitive adhesive comprises, in percentages by weight: 10-70% of a matrix resin, 10-70% of a tackifying resin, 0.1-5% of an antioxidant, 0-20% of a plasticizer, 10-50% of a solid powder flame retardant and 0.1-3% of an anti-aging agent, wherein the matrix resin comprises a polymer elastomer, the polymer elastomer having a melt index greater than or equal to 5 g / 10 min under a temperature of 200°C and a load of 5.0 kg; and the solid powder flame retardant has a particle size less than 35 μm and a D50 less than or equal to 20 μm. The flame-retardant transparent hot-melt pressure-sensitive adhesive has a softening point of 80-140°C, a transparency of greater than or equal to 50%, and a haze of less than or equal to 80%. The flame-retardant transparent hot-melt pressure-sensitive adhesive provided in the present invention has excellent comprehensive properties, such as adhesion and flame retardance, and is particularly suitable for the rapid bonding of optical cables, such that an optical cable product is transparent, aesthetic, and convenient and safe to use.

Description

A flame-retardant transparent hot-melt pressure-sensitive adhesive and its preparation method and application Technical Field

[0001] The present invention belongs to the technical field of hot melt pressure sensitive adhesives, in particular to the technology of flame retardant transparent hot melt pressure sensitive adhesives, and more particularly relates to a flame retardant transparent hot melt pressure sensitive adhesive and a preparation method and application thereof. Background Art

[0002] Fiber-optic communications have greatly facilitated people's lives, but traditional optical cables require tape or staples to be attached to walls, which not only damages the wall but is also cumbersome. Adhesive bonding is less destructive and relatively simple to use. Choosing the right adhesive also allows for transparent optical cables, also known as invisible cables. These cables, which require no conduit, are not only aesthetically pleasing but can also be quickly and easily installed around skirtings, doors, windows, and decorative strips, meeting home entrance requirements with minimal disruption to residents.

[0003] Regarding specific bonding methods, two methods are generally used: self-adhesive layer and external adhesive layer. The external adhesive layer method usually uses a special hot melt glue gun to heat the glue during construction, and then squeezes the hot melt glue between the wall and the optical cable to bond. Although the optical cable is easy to produce, the optical cable as a whole must have high temperature resistance, and the construction requires high professionalism and difficulty. The self-adhesive layer method directly uses heated self-adhesive coating glue to bond the invisible optical cable to the wall during construction. The advantage is that the construction is relatively convenient, but due to the need for heating and other operations, there are still defects such as reduced transparency and appearance after bonding. Patent application CN105969252A discloses a stealth optical cable and self-adhesive coating. The cable comprises, from the inside out, a natural optical fiber, a transparent tight jacket, and a self-adhesive coating. The self-adhesive coating is constructed using a self-adhesive coating composed, by weight, of 40-45% ethylene-ethyl acrylate copolymer, 11-15% tackifier, 25-30% synthetic wax or petroleum-derived wax, and the remainder of other additives, such as 2-5% polyvinyl chloride flame retardant. By employing the appropriate formulation and proportions of the ethylene-ethyl acrylate copolymer, the invention achieves high transparency, a long open time, and excellent uncured strength or initial tack after curing. For example, patent CN111029006B discloses a hybrid optoelectronic cable, comprising a hybrid cable core and a transparent flame-retardant self-adhesive coating layer, wherein the hybrid cable core comprises a plurality of optical fibers, a transparent second sheath and a support frame, wherein the plurality of optical fibers are fixed in the support frame; the flame-retardant self-adhesive coating layer is wrapped around the outer surface of the hybrid cable core, and the self-adhesive coating portion is melted by heating so that the entire invisible optoelectronic hybrid cable is adhered and fixed to the wall. However, the main resin of the above invention has low bonding strength, insufficient heat resistance and flame retardancy, and is difficult to meet the requirements of long-term safety and stability. In addition, the adhesive layer needs to be heated, melted, and then bonded during construction, which is technically difficult and has low construction efficiency, making it difficult to meet the requirements of large-scale and rapid construction.

[0004] Therefore, how to provide an adhesive that can be used for rapid bonding of optical cables, ensuring high bonding performance and ease of construction while providing comprehensive properties such as transparency, aesthetics, heat resistance, flame retardancy, durability and stability, has become a technical problem that needs to be urgently solved in this field. Summary of the Invention

[0005] In response to the defects in the above-mentioned prior art, the purpose of the present invention is to provide a flame-retardant transparent hot-melt pressure-sensitive adhesive and its preparation method and application. The present invention provides excellent bonding performance for optical cables while ensuring that the fixed optical cables are transparent, beautiful, convenient and safe to use by regulating the ratio of the components of the hot-melt pressure-sensitive adhesive and the particle size of the material.

[0006] In a first aspect, the present invention provides a flame retardant transparent hot melt pressure sensitive adhesive. Based on the total weight of the flame retardant transparent hot melt pressure sensitive adhesive being 100%, the flame retardant transparent hot melt pressure sensitive adhesive comprises the following components in percentage by weight:

[0007] Main resin 10-70%;

[0008] Tackifying resin 10-70%;

[0009] Antioxidant 0.1-5%;

[0010] Plasticizer 0-20%;

[0011] Solid powder flame retardant 10-50%;

[0012] Anti-aging agent 0.1-3%,

[0013] The main resin includes a polymer elastomer, and the polymer elastomer has a melt index of ≥5g / 10min at a temperature of 200°C and a load of 5.0kg;

[0014] Solid powder flame retardant particle size <35μm and D50≤20μm;

[0015] The flame retardant transparent hot melt pressure sensitive adhesive has a softening point of 80-140° C., a transparency of 50% or more, and a haze of 80% or less.

[0016] The present invention can effectively adjust the softening point of the hot melt pressure-sensitive adhesive by adjusting the content of the main resin and the tackifying resin. The softening point of the hot melt pressure-sensitive adhesive is within the range of 80°C-140°C, which can meet the long-term stable bonding requirements in various usage scenarios. Among them, for those with high-temperature storage and transportation requirements, the softening point is preferably 95-140°C to prevent the occurrence of high-temperature adhesive overflow. When a formula with a slightly lower softening point is selected, the processing temperature can be appropriately lowered, reducing production energy consumption and costs. The flexible adjustability of the flame-retardant transparent hot melt pressure-sensitive adhesive formula of the present invention can take into account cost savings and various practical application requirements on the basis of meeting the comprehensive properties such as flame retardancy, transparency, and bonding strength.

[0017] In addition, the particle size of the solid powder flame retardant affects its compatibility and dispersibility in the glue system, which in turn affects the transparency, haze, and adhesion of the hot melt pressure-sensitive adhesive. After preliminary screening, the present invention uses laser diffraction to measure the particle size D50 of the solid powder flame retardant to obtain a suitable particle size range. The D50 particle size refers to the particle size distribution curve of the particulate matter, and 50% of the particles have a particle size less than or equal to this value. D50 is also called the median diameter or median particle size. The solid powder flame retardant is screened to obtain a suitable particle size range, which can be combined with the resin matrix to take into account flame retardancy, light transmission performance, and bonding performance.

[0018] Plasticizers are primarily used to reduce the viscosity of hot melt adhesives, increase their melting speed, facilitate wetting of adherend surfaces, and enhance their flexibility. Mineral oils are preferred, selected from one or more of white oil, naphthenic oil, and paraffin oil. Antioxidants are primarily used to improve the thermal stability of hot melt adhesives, prevent aging of their physical properties, and reduce color changes. These antioxidants are preferably a combination of antioxidant 168 and antioxidant 1010, with the ratio of antioxidant 168 to antioxidant 1010 being 0.2-5:1. The weathering resistance of hot melt pressure-sensitive adhesives is enhanced by the addition of an anti-aging agent. The anti-aging agent is preferably a combination of TiO2 nanoparticles and a light stabilizer, with the light stabilizer being selected from one or more of UV944 and UV622. More preferably, the ratio of TiO2 nanoparticles to light stabilizer is 1-20:100.

[0019] Furthermore, the polymer elastomer is selected from one or more of the following groups: styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butadiene-styrene copolymer (SEBS), hydrogenated styrene isoprene diblock copolymer (SEP), styrene-ethylene / propylene-styrene block copolymer (SEPS), styrene-isoprene-styrene block copolymer (SIS), butyl rubber (IIR), polyisobutylene (PIB), nitrile rubber (NBR), isoprene rubber (IR), poly(butadiene-acrylonitrile) (PBAN), synthetic polyolefin rubber (SPR), and poly(butadiene-styrene) (PBS).

[0020] Furthermore, the tackifying resin has a softening point of 60-150°C and is selected from at least one of natural resins and synthetic resins. The natural resins include one or more of rosin, rosin derivatives, and terpene resins; and the synthetic resins include one or more of petroleum resins, coumarone-indene resins, and styrene resins. Tackifying resins are small molecule compounds that increase viscosity, especially surface viscosity, and have a high glass transition temperature. Tackifying resins can also improve wetting and initial tack.

[0021] Furthermore, the main resin also includes an α-olefin copolymer, and the weight ratio of the α-olefin copolymer to the polymer elastomer is (1-30):100.

[0022] Furthermore, the solid powder flame retardant comprises 15-40% by weight, has a particle size less than 25 μm, and has a D50 value of 0.1 μm ≤ ≤ 15 μm. It is selected from at least one of a phosphorus-based flame retardant and a nitrogen-based flame retardant. Preferably, the flame retardant comprises a phosphorus-based flame retardant and a nitrogen-based flame retardant blended in a weight ratio of 100:(5-10). Specifically, the phosphorus-based flame retardant may include one or more metal phosphinates and ammonium polyphosphate, and the nitrogen-based flame retardant may include one or more melamine and its salts.

[0023] Furthermore, the flame retardant also includes a flame retardant additive, comprising 1-5% by weight of the total flame retardant, comprising mesoporous silica with a particle size less than 25 μm and an average pore size of 10-50 nm. Mesoporous silica, due to its small size, colorless transparency, and high visible light transmittance, as well as its high thermal stability and porous smoke suppression properties, synergizes with the flame retardant to enhance the flame retardant properties of the product without substantially affecting the product's light transmittance.

[0024] In a second aspect, the present invention further provides a method for preparing the aforementioned flame retardant transparent hot melt pressure sensitive adhesive, comprising the following steps:

[0025] S1. Add the main resin, tackifying resin, antioxidant, anti-aging agent and optional plasticizer to the preheated reaction equipment, and stir thoroughly to obtain premix A;

[0026] S2. Add flame retardant to premix A, stir thoroughly, and evacuate to obtain a flame retardant transparent hot melt pressure sensitive adhesive product.

[0027] Thirdly, in order to better utilize the flame-retardant transparent hot-melt pressure-sensitive adhesive, its application in optical cable bonding is provided.

[0028] Specifically, the optical cable bonding includes the following steps:

[0029] (1) performing corona treatment on at least part of the outer surface of the optical cable;

[0030] (2) melting the flame-retardant transparent hot-melt pressure-sensitive adhesive and applying it to at least the area of ​​the outer surface of the optical cable that has been corona treated, and cooling and shaping the adhesive;

[0031] (3) Applying pressure to the optical cable, and bonding the optical cable to the target object through the flame-retardant transparent hot-melt pressure-sensitive adhesive.

[0032] The present invention includes at least the following advantages:

[0033] 1. Through strict material selection and formula design, the present invention provides a safe, durable, transparent and beautiful hot-melt pressure-sensitive adhesive for transparent optical cables. When used, only a certain amount of pressure is required to complete the bonding of the hot-melt pressure-sensitive adhesive. In actual laying construction, the bonding portion of the optical cable is brought into contact with the wall surface, and force is applied to the bonding portion by squeezing or pressing the optical cable to bond the bonding portion to the wall surface, thereby quickly, stably and reliably bonding the optical cable to the wall surface. There is no need to repeatedly apply or heat the adhesive layer on the optical cable. The operation is simple and convenient, the application scenarios are diverse, and the laying efficiency of the optical cable is significantly improved. In addition, the hot-melt pressure-sensitive adhesive has a simple production process, stable product quality, and has the advantage of large-scale continuous production.

[0034] 2. Based on the use of small-particle nitrogen-phosphorus flame retardants, the present invention further prepares a mesoporous silica flame retardant additive, utilizing its small size, colorless transparency, high visible light transmittance, high thermal stability, porous smoke suppression and other advantages, to synergistically enhance the flame retardant properties of the product with the flame retardant without basically affecting the transmittance of the product. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in further detail below.

[0036] A flame-retardant transparent hot-melt pressure-sensitive adhesive, in particular a flame-retardant transparent hot-melt pressure-sensitive adhesive for rapid bonding of optical cables, comprising the following components by weight:

[0037] (1) Main resin 10-70%, including:

[0038] 1.1. Polymer elastomer, wherein the polymer elastomer has a melt index of ≥5 g / 10 min, preferably ≥6 g / 10 min, at a temperature of 200° C. and a load of 5.0 kg. Specifically, the polymer elastomer is selected from one or more of the following groups: styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butadiene-styrene copolymer (SEBS), hydrogenated styrene-isoprene diblock copolymer (SEP), styrene-ethylene / propylene-styrene block copolymer (SEPS), styrene-isoprene-styrene block copolymer (SIS), butyl rubber (IIR), polyisobutylene (PIB), nitrile rubber (NBR), isoprene rubber (IR), poly(butadiene-acrylonitrile) (PBAN), synthetic polyolefin rubber (SPR), and poly(butadiene-styrene) (PBS);

[0039] 1.2. Optionally, an α-olefin copolymer, wherein the weight ratio of the α-olefin copolymer to the polymer elastomer is (1-30):100; the structural formula of the α-olefin copolymer (APAO) is:

[0040]

[0041] (2) 10-70% of a tackifying resin having a softening point of 60-150°C, selected from at least one of a natural resin and a synthetic resin, wherein the natural resin includes one or more of rosin, rosin derivatives, and terpene resins, and the synthetic resin includes one or more of petroleum resin, coumarone-indene resin, and styrene resin;

[0042] (3) 0.1-5% antioxidant, preferably a mixture of antioxidant 168 and antioxidant 1010, particularly preferably, antioxidant 168 and antioxidant 1010 are mixed in a mass ratio of (0.2-5):1;

[0043] (4) Plasticizer 0-20%, preferably 2-20%, preferably mineral oil, selected from one or more of white oil, naphthenic oil, and paraffin oil;

[0044] (5) 10-50%, preferably 15-40%, of solid powder flame retardant, with a particle size of <35μm and D50≤20μm, preferably a particle size of <25μm and 0.1μm≤D50≤15μm, selected from at least one of phosphorus-based flame retardants and nitrogen-based flame retardants, preferably phosphorus-based flame retardants and nitrogen-based flame retardants are compounded in a weight ratio of 100:(5-10); the flame retardant also includes a flame retardant auxiliary agent accounting for 1-5% of the total weight of the flame retardant, the flame retardant auxiliary agent includes mesoporous silica, the mesoporous silica particle size is <25μm, and the average pore size is 10-50nm. Mesoporous silica can be purchased commercially and sieved, or it can be homemade by the following steps:

[0045] A. Stir cetyltrimethylammonium bromide (CTAB) and 1-3 mol / L NaOH solution until uniform;

[0046] B. Add ethyl silicate (TEOS) dropwise, stir vigorously at 80-90°C for 2-3 h, centrifuge, wash and dry to obtain a white precipitate;

[0047] C. Grind the white precipitate and mix it with acidic methanol solution, reflux condense, and reflux with magnetic stirring at 70-90℃ for 6-10 h;

[0048] D. ultrasonically dispersing and washing with deionized water, drying after high-speed centrifugation to obtain mesoporous silica, wherein the average pore size of the mesoporous silica is 10-50 nm;

[0049] E. Screening to obtain mesoporous silica with a particle size of less than 25 μm.

[0050] The process of making homemade mesoporous silica is simple, the particle size and pore size can be easily controlled, and subsequent surface modifications such as corona and plasma can be performed to improve its dispersibility and resin compatibility.

[0051] (6) 0.1-3% of an anti-aging agent, preferably a combination of TiO2 nanoparticles and a light stabilizer, wherein the light stabilizer is selected from one or more of UV944 and UV622, and more preferably, the mass ratio of the TiO2 nanoparticles to the light stabilizer is (1-20):100;

[0052] The flame-retardant transparent hot-melt pressure-sensitive adhesive has a softening point of 80-140° C., a transparency of 50% or more, and a haze of 80% or less.

[0053] A method for preparing the aforementioned flame-retardant transparent hot-melt pressure-sensitive adhesive, in particular a method for preparing a flame-retardant transparent hot-melt pressure-sensitive adhesive for rapid bonding of optical cables, comprises the following steps:

[0054] S1. Raise the temperature of the reaction equipment to above 100° C., preferably above 120° C., more preferably 140-180° C.; add the main resin, plasticizer, tackifying resin, antioxidant and anti-aging agent to the preheated reaction equipment, and stir thoroughly to obtain premix A;

[0055] S2. Add flame retardant to premix A, stir thoroughly, and evacuate to obtain a flame retardant transparent hot melt pressure sensitive adhesive product.

[0056] An application of the aforementioned flame-retardant transparent hot-melt pressure-sensitive adhesive in optical cable bonding, the application mainly includes preparing an optical cable with the flame-retardant transparent hot-melt pressure-sensitive adhesive, and bonding the optical cable. Specifically, the optical cable bonding includes the following steps:

[0057] (1) performing corona treatment on at least part of the outer surface of the optical cable;

[0058] (2) melting the flame-retardant transparent hot-melt pressure-sensitive adhesive and applying it to at least the area of ​​the outer surface of the optical cable that has been corona treated, and cooling and shaping the adhesive;

[0059] (3) Applying pressure to the optical cable, and bonding the optical cable to the target object through the flame-retardant transparent hot-melt pressure-sensitive adhesive.

[0060] Adjust the nozzle size of the hot melt pressure-sensitive adhesive dispensing equipment based on the production environment. For example, adjust the amount of glue required based on the width and thickness of the optical cable. If the inner diameter of the nozzle is too small, the glue will not be easily sprayed out. If it is too large, it will cause turbulent glue flow or excessive glue. Therefore, the inner diameter of the nozzle of the hot melt adhesive dispensing equipment should be set to 0.1-5mm.

[0061] The outward bonding operation of the optical cable of the present invention is simple and safe, with low construction intensity and mild conditions, and can meet the needs of various scenarios and various groups of people, and also has the prospect of popularization and application.

[0062] The embodiments of the present invention will be clearly and completely described below in conjunction with Preparation Examples AC and corresponding Examples of the present invention. Obviously, the embodiments described 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 fall within the scope of protection of the present invention. The main materials used in the embodiments of the present invention are only for experimental reference and are not necessary limitations on the technical solutions of the present invention. Based on the present invention, those skilled in the art can purchase or make the corresponding raw materials as needed.

[0063] Preparation Example A

[0064] Examples A1-A2: The temperature of the high-temperature stirring reaction equipment is raised to 150°C, and then styrene-isoprene-styrene block copolymer (SIS), α-olefin copolymer (APAO), tackifying resin, mineral oil, antioxidant, and aging resistance agent are added thereto, and the mixture is stirred thoroughly to obtain premix A; thereafter, a solid powder flame retardant (AP423 screened to obtain a particle size greater than 10 μm and less than 25 μm, D50 of 16±0.5 μm; MCA, D50 of approximately 2 μm) is added to the premix A, and the mixture is stirred thoroughly until the reaction is uniform, and vacuum is applied to obtain hot-melt pressure-sensitive adhesive Examples A1 and A2, and finally the material is filled and discharged.

[0065] Example A3: The temperature of the high-temperature stirring reaction equipment is raised to 150°C, and then styrene-isoprene-styrene block copolymer (SIS), α-olefin copolymer (APAO), tackifying resin, mineral oil, antioxidant, and aging resistance agent are added thereto, and the mixture is fully stirred to obtain premix A; thereafter, a solid powder flame retardant (AP423 screened to obtain a particle size greater than 5 μm and less than 20 μm, D50 of 12±0.5 μm; MCA, D50 of approximately 2 μm) and a homemade mesoporous silica flame retardant additive are added to the premix A, and the mixture is fully stirred until the reaction is uniform, and vacuum is applied to obtain hot melt pressure-sensitive adhesive Example A3, and finally the material is filled and discharged.

[0066] Comparative Example A4: Raise the temperature of the high-temperature stirring reaction equipment to 150°C, then add styrene-isoprene-styrene block copolymer (SIS), α-olefin copolymer (APAO), tackifying resin, mineral oil, antioxidant, and aging resistance agent, stir thoroughly until the reaction is uniform, evacuate to obtain hot melt pressure-sensitive adhesive Comparative Example A4, and finally fill and discharge.

[0067] Comparative Example A5: The temperature of the high-temperature stirring reaction apparatus was raised to 150°C. Styrene-isoprene-styrene block copolymer (SIS), α-olefin copolymer (APAO), tackifying resin, mineral oil, antioxidant, anti-aging agent, and flame retardant (AP462, screened particle size approximately 52-58 μm) were then added. The mixture was thoroughly stirred until a uniform reaction occurred. Vacuum was then applied to obtain the hot-melt pressure-sensitive adhesive Comparative Example A5. The mixture was then filled and discharged. The specific ingredients and proportions of A1-A5 are shown in Table 1:

[0068] Table 1. Components and ratios used to prepare hot melt pressure sensitive adhesives A1, A2, A3, A4 and A5

[0069]

[0070] Preparation Example B

[0071] Example B1-B2: The temperature of the high-temperature stirring reaction equipment is raised to 150°C, and then styrene-butadiene-styrene block copolymer (SBS), α-olefin copolymer (APAO), tackifying resin, mineral oil, antioxidant, and aging resistance agent are added thereto, and the mixture is fully stirred to obtain premix A; then, a solid powder flame retardant (AP423 screened to obtain a particle size greater than 10 μm and less than 25 μm, D50 of 16±0.5 μm; MCA, D50 of approximately 2 μm) is added to the premix A, and the mixture is fully stirred until the reaction is uniform, and vacuum is applied to obtain hot-melt pressure-sensitive adhesive Examples B1 and B2, and finally the material is filled and discharged.

[0072] Example B3: The temperature of the high-temperature stirring reaction equipment is raised to 150°C, and then styrene-butadiene-styrene block copolymer (SBS), α-olefin copolymer (APAO), tackifying resin, mineral oil, antioxidant, and aging resistance agent are added thereto, and the mixture is fully stirred to obtain premix A; thereafter, a solid powder flame retardant (AP423 screened to obtain a particle size greater than 5 μm and less than 20 μm, D50 of 12±0.5 μm; MCA, D50 of approximately 2 μm) and a homemade mesoporous silica flame retardant additive are added to the premix A, and the mixture is fully stirred until the reaction is uniform, and vacuum is applied to obtain the hot melt pressure-sensitive adhesive Example B3, and finally the material is filled and discharged.

[0073] Comparative Example B4: The temperature of the high-temperature stirring reaction equipment was raised to 150°C, and then styrene-butadiene-styrene block copolymer (SBS), α-olefin copolymer (APAO), tackifying resin, mineral oil, antioxidant, and aging resistance agent were added thereto. The mixture was stirred thoroughly until the reaction was uniform, and vacuum was applied to obtain the hot melt pressure-sensitive adhesive comparative example B4. Finally, the material was filled and discharged.

[0074] Comparative Example B5: The temperature of the high-temperature stirring reaction apparatus was raised to 150°C. Styrene-butadiene-styrene block copolymer (SBS), α-olefin copolymer (APAO), tackifying resin, mineral oil, antioxidant, anti-aging agent, and flame retardant (AP462, screened with a particle size of approximately 52-58 μm) were then added. The mixture was thoroughly stirred until the reaction was uniform. Vacuum was then applied to obtain the hot-melt pressure-sensitive adhesive Comparative Example B5. The mixture was then filled and discharged. The specific ingredients and proportions of B1-B5 are shown in Table 2:

[0075] Table 2. Components and ratios used to prepare hot melt pressure sensitive adhesives B1, B2, B3, B4 and B5

[0076]

[0077] Preparation Example C

[0078] Examples C1-C2: The temperature of the high-temperature stirring reaction equipment is raised to 150°C, and then styrene-ethylene / propylene-styrene block copolymer (SEPS), α-olefin copolymer (APAO), tackifying resin, mineral oil, antioxidant, and aging resistance agent are added thereto, and the mixture is thoroughly stirred to obtain a premix A; thereafter, a solid powder flame retardant (AP423 screened to obtain a particle size greater than 10 μm and less than 25 μm, with a D50 of 16±0.5 μm; MCA, with a D50 of approximately 2 μm) is added to the premix A, and the mixture is thoroughly stirred until the reaction is uniform, and vacuum is applied to obtain hot-melt pressure-sensitive adhesive Examples C1 and C2, and finally the material is filled and discharged.

[0079] Example C3: The temperature of the high-temperature stirring reaction equipment is raised to 150°C, and then styrene-ethylene / propylene-styrene block copolymer (SEPS), α-olefin copolymer (APAO), tackifying resin, mineral oil, antioxidant, and aging resistance agent are added thereto, and the mixture is stirred thoroughly to obtain premix A; then, a solid powder flame retardant (AP423 screened to obtain a particle size greater than 5 μm and less than 20 μm, D50 of 12±0.5 μm; MCA, D50 of approximately 2 μm) and a homemade mesoporous silica flame retardant additive are added to the premix A, and the mixture is stirred thoroughly until the reaction is uniform, and vacuum is applied to obtain the hot melt pressure-sensitive adhesive Example C3, and finally the material is filled and discharged.

[0080] Comparative Example C4: The temperature of the high-temperature stirring reaction equipment was raised to 150°C, and then styrene-ethylene / propylene-styrene block copolymer (SEPS), α-olefin copolymer (APAO), tackifying resin, mineral oil, antioxidant, and aging resistance agent were added thereto. The mixture was stirred thoroughly until the reaction was uniform, and vacuum was applied to obtain the hot melt pressure-sensitive adhesive comparative example C4. Finally, the material was filled and discharged.

[0081] Comparative Example C5: The temperature of the high-temperature stirring reaction apparatus was raised to 150°C. Styrene-ethylene / propylene-styrene block copolymer (SEPS), α-olefin copolymer (APAO), tackifying resin, mineral oil, antioxidant, anti-aging agent, and flame retardant (AP462, screened with a particle size of approximately 52-58 μm) were then added. The mixture was thoroughly stirred until the reaction was uniform. Vacuum was then applied to obtain the hot-melt pressure-sensitive adhesive Comparative Example C5. The mixture was then filled and discharged. The specific ingredients and proportions of C1-C5 are shown in Table 3:

[0082] Table 3. Components and ratios used to prepare hot melt pressure sensitive adhesives C1, C2, C3, C4 and C5

[0083]

[0084] The main materials used in the present invention are shown in Table 4. The following materials are only for experimental reference and are not necessarily limiting the technical solution of the present invention. Based on the present invention, those skilled in the art can purchase or make the corresponding raw materials as needed.

[0085] Table 4. Raw materials list

[0086]

[0087] The melt index test conditions in Table 4 are as follows: the test is performed at a temperature of 200° C. and a load of 5.0 kg.

[0088] The aforementioned homemade mesoporous silica is prepared by the following steps:

[0089] A. Stir CTAB (cetyltrimethylammonium bromide, purchased from Hubei Kemaidi) and 1-3 mol / L NaOH solution evenly;

[0090] B. Add TEOS (ethyl silicate or ethyl orthosilicate, purchased from Kandis Chemical) dropwise, stir vigorously at 80-90°C for 2-3 hours, centrifuge, wash, and dry to obtain a white precipitate;

[0091] C. Grind the white precipitate and mix it with acidic methanol solution, reflux condense, and reflux with magnetic stirring at 70-90℃ for 6-10 h;

[0092] D. ultrasonically dispersing and washing with deionized water, drying after high-speed centrifugation to obtain mesoporous silica, wherein the average pore size of the mesoporous silica is 10-50 nm;

[0093] E. Screening to obtain mesoporous silica with a particle size of less than 25 μm.

[0094] Test methods and results:

[0095] (1) Softening point test

[0096] Test method: Melt the hot melt pressure sensitive adhesive sample into a ring mold, let it stand for 24 hours, and then use a softening point tester to test the softening point of the material.

[0097] (2) Haze and transparency test

[0098] Test method: At 170°C, use a knife coater to coat a hot melt pressure-sensitive adhesive sample on the release surface of a 50μm transparent PET release film. Control the film thickness to 400μm. Then, use a haze tester to test the haze and transparency of the pressure-sensitive adhesive sample. The test method refers to the test method in GB / T2410-2008 Transparent Plastics - Determination of Light Transmittance and Haze.

[0099] (3) Flame retardant performance test

[0100] (3.1) Test method: Refer to GB / T 16172-2007 Test method for heat release rate of building materials.

[0101] (3.2) Test method: Apply hot melt pressure sensitive adhesive to the optical cable and test the flame retardant performance of the finished cable. For specific test methods, please refer to IEC 60332-1-2 and EN50399.

[0102] (4) Test on the adhesion of wooden boards

[0103] Test method: Coat the hot-melt pressure-sensitive adhesive sample on the optical cable (width 3.2mm, thickness 1.3mm, length 100mm), control the width of the hot-melt pressure-sensitive adhesive layer to 3.2mm, thickness to 0.4mm, and length to 100mm, then cover the optical cable specimen coated with the hot-melt pressure-sensitive adhesive sample on the beech wood board substrate (width 100mm, thickness 5mm, length 200mm). After placing it at 23°C for 4 hours, test the 90° peel force, measure it in parallel 4 times, and take the average value.

[0104] (5) Latex paint adhesion test

[0105] Test method: Coat the hot-melt pressure-sensitive adhesive sample on the optical cable (width 3.2mm, thickness 1.3mm, length 100mm), control the width of the hot-melt pressure-sensitive adhesive layer to 3.2mm, thickness 0.4mm, length 100mm, and then fully cover the optical cable specimen coated with the hot-melt pressure-sensitive adhesive sample on the substrate coated with latex paint (width 100mm, thickness 2mm, length 200mm). After placing it at 23°C for 4 hours, test the 90° peel strength, measure it in parallel 4 times, and take the average value.

[0106] (6) Wallpaper adhesion test

[0107] Test method: Coat the hot-melt pressure-sensitive adhesive sample on the optical cable (width 3.2mm, thickness 1.3mm, length 100mm), control the width of the hot-melt pressure-sensitive adhesive layer to 3.2mm, thickness to 0.4mm, and length to 100mm, then cover the optical cable sample coated with the hot-melt pressure-sensitive adhesive sample on the PVC wallpaper substrate (width 100mm, thickness 0.5mm, length 200mm). After placing it at 23°C for 4 hours, test the 90° peel force, measure it in parallel 4 times, and take the average value.

[0108] (7) Thermal stability test

[0109] Test method: Coat the hot-melt pressure-sensitive adhesive sample on the optical cable (width 3.2mm, thickness 1.3mm, length 100mm), control the width of the hot-melt pressure-sensitive adhesive layer to 3.2mm, thickness 0.4mm, length 100mm, and then cover the optical cable specimen coated with the hot-melt pressure-sensitive adhesive sample on the beech wood board substrate (width 100mm, thickness 5mm, length 200mm). After placing it in a 70℃ oven for 48 hours, observe whether there is any glue overflow, and test the 90° peel strength. Measure it four times in parallel and take the average value.

[0110] (8) Low temperature stability test

[0111] Test method: Using beech wood board as the substrate, the hot melt pressure-sensitive adhesive sample is coated on the optical cable (width 3.2mm, thickness 1.3mm, length 100mm), and the width of the hot melt pressure-sensitive adhesive layer is controlled to be 3.2mm, the thickness is 0.4mm, and the length is 100mm. Then, the optical cable specimen coated with the hot melt pressure-sensitive adhesive sample is fully covered on the beech wood board substrate (width 100mm, thickness 5mm, length 200mm). After placing it in a walk-in refrigerator at 5℃ for 4h, the 90° peel force is tested. The test is carried out in parallel 4 times and the average value is taken.

[0112] The results of tests (1) to (3) are shown in Table 5:

[0113] Table 5 Test results of examples and comparative examples

[0114]

[0115] The softening points of the pressure-sensitive adhesives prepared in Examples A1-A3, B1-B3, and C1-C3 of the present invention ranged from 80°C to 140°C, particularly from 95°C to 140°C. This demonstrates that the hot-melt pressure-sensitive adhesives of the present invention possess good thermal stability and can maintain high bulk strength at high temperatures. Overall, the samples using the flame retardant exhibited high thermal stability.

[0116] The haze of the hot-melt pressure-sensitive adhesive samples in each example was less than 30%, and the transparency was greater than 80%, generally above 85%, indicating that the hot-melt pressure-sensitive adhesive of the present invention has good transparency. Comparative Examples A4, B4, and C4, which do not use flame retardants, showed little change compared to the examples and had good transparency. However, the haze of Comparative Examples A5, B5, and C5 all exceeded 70%, and the transparency was significantly reduced, indicating that the choice of flame retardant and the particle size have a significant impact on the optical properties of the pressure-sensitive adhesive.

[0117] The peak heat release rate of the hot melt pressure sensitive adhesives of Examples A1-A3, B1-B3, C1-C3 is 280-400 kW / m 2 The flame retardant grade of the finished cable is D2ca. The peak heat release rate of the hot melt pressure sensitive adhesive of the comparative examples A4, B4 and C4 exceeds 500kW / m 2 The above test results show that the hot melt pressure sensitive adhesive of the present invention has good flame retardant properties.

[0118] The results of tests (4) to (6) are shown in Table 6:

[0119] Table 6 Test results of examples and comparative examples

[0120]

[0121] The hot-melt pressure-sensitive adhesive samples from various examples of the present invention exhibited adhesion to wood panels exceeding 1.5 N / mm, and all failed due to adhesion to the cable and interfacial damage with the wood panel. The test results demonstrate the excellent adhesion of hot-melt pressure-sensitive adhesives to optical cables, and the good adhesion of optical cables made with the hot-melt pressure-sensitive adhesive of the present invention to wood panels.

[0122] The HMPSA samples from various examples of the present invention exhibited adhesion greater than 1.6 N / mm to latex paint, with all failure modes being cohesive failure within the adhesive layer. The test results demonstrate that optical cables employing the HMPSA of the present invention exhibit excellent adhesion to latex paint.

[0123] The hot-melt pressure-sensitive adhesive samples from each example of the present invention all exhibited adhesion to wallpaper exceeding 1.2 N / mm, and the failure mode in all cases was adhesion to the cable, resulting in interfacial damage between the adhesive and the wallpaper. The test results demonstrate the excellent adhesion of hot-melt pressure-sensitive adhesives to optical cables, and the good adhesion of optical cables made with the hot-melt pressure-sensitive adhesive of the present invention to wallpaper.

[0124] The results of tests (7) to (8) are shown in Table 7:

[0125] Table 7 Test results of examples and comparative examples

[0126]

[0127] Thermal stability test results show that at 70°C, the adhesive strength of the hot-melt pressure-sensitive adhesive samples of each embodiment of the present invention to the wood board was greater than 1.5N / mm, and the failure mode was adhesion to the cable, resulting in interfacial damage with the wood board. Compared to the adhesive strength to the wood board at room temperature of 23°C, the 70°C storage temperature had little effect on the adhesive strength. Furthermore, after 48 hours of storage at 70°C, the hot-melt pressure-sensitive adhesive samples of each embodiment did not experience adhesive overflow, while the hot-melt pressure-sensitive adhesive samples of Comparative Examples A4, B4, and C4 all experienced varying degrees of adhesive overflow. These test results demonstrate that the hot-melt pressure-sensitive adhesive samples of each embodiment of the present invention have good thermal stability, and optical cables using the hot-melt pressure-sensitive adhesive layer of the present invention can well adapt to high-temperature environments.

[0128] As for the low-temperature stability test results, at 5°C, the adhesion strength of the hot-melt pressure-sensitive adhesive samples of each embodiment is not less than 1N / mm. The test results prove that the hot-melt pressure-sensitive adhesive of the embodiment of the present invention has good low-temperature resistance. The optical cable using the hot-melt pressure-sensitive adhesive layer of the present invention can better adapt to low-temperature environments.

[0129] The above introduces the preferred embodiments of the present invention, which is intended to make the spirit of the present invention clearer and easier to understand, and is not intended to limit the present invention. Any modifications, replacements, and improvements made within the spirit and principles of the present invention should be included in the scope of protection required by the present invention.

Claims

1. A flame retardant transparent hot melt pressure sensitive adhesive, characterized in that: Taking the total weight of the flame retardant transparent hot melt pressure sensitive adhesive as 100%, the flame retardant transparent hot melt pressure sensitive adhesive includes the following components in weight percentage: Main resin 10-70%; Tackifying resin 10-70%; Antioxidant 0.1-5%; Plasticizer 0-20%; Solid powder flame retardant 10-50%; Anti-aging agent 0.1-3%, The main resin includes a polymer elastomer, and the melt index of the polymer elastomer at a temperature of 200° C. and a load of 5.0 kg is ≥5 g / 10 min; The particle size of solid powder flame retardant is less than 35 μm and D50 is less than or equal to 20 μm; The flame retardant transparent hot melt pressure sensitive adhesive has a softening point of 80-140° C., a transparency of ≥50%, and a haze of ≤80%.

2. The flame retardant transparent hot melt pressure sensitive adhesive according to claim 1, characterized in that: The polymer elastomer is selected from one or more of the following groups: styrene-butadiene-styrene block copolymer, styrene-ethylene-butadiene-styrene copolymer, hydrogenated styrene isoprene diblock copolymer, styrene-ethylene / propylene-styrene block copolymer, styrene-isoprene-styrene block copolymer, butyl rubber, polyisobutylene, nitrile rubber, isoprene rubber, poly(butadiene-acrylonitrile), synthetic polyolefin rubber, poly(butadiene-styrene).

3. The flame retardant transparent hot melt pressure sensitive adhesive according to claim 2, characterized in that: The tackifying resin has a softening point of 60-150°C and is selected from at least one of natural resin and synthetic resin; The natural resin includes one or more of rosin, rosin derivatives, and terpene resins; The synthetic resin includes one or more of petroleum resin, coumarone-indene resin and styrene resin.

4. The flame retardant transparent hot melt pressure sensitive adhesive according to any one of claims 1 to 3, characterized in that: The main resin also includes an α-olefin copolymer, and the weight ratio of the α-olefin copolymer to the polymer elastomer is (1-30):

100.

5. The flame retardant transparent hot melt pressure sensitive adhesive according to any one of claims 1 to 3, characterized in that: The weight percentage of the solid powder flame retardant is 15-40%, the particle size is less than 25 μm, and 0.1 μm≤D50≤15 μm, and the solid powder flame retardant is selected from at least one of a phosphorus-based flame retardant and a nitrogen-based flame retardant.

6. The flame retardant transparent hot melt pressure sensitive adhesive according to claim 5, characterized in that: The flame retardant comprises a phosphorus-based flame retardant and a nitrogen-based flame retardant in a weight ratio of 100:(5-10).

7. The flame retardant transparent hot melt pressure sensitive adhesive according to claim 6, characterized in that: The flame retardant further comprises a flame retardant auxiliary agent accounting for 1-5% of the total weight of the flame retardant, wherein the flame retardant auxiliary agent comprises mesoporous silica, the particle size of the mesoporous silica is less than 25 μm, and the average pore size is 10-50 nm.

8. A method for preparing the flame retardant transparent hot melt pressure sensitive adhesive according to any one of claims 1 to 7, characterized in that: The steps include: S1, adding the main resin, tackifying resin, antioxidant, anti-aging agent and optional plasticizer into the preheated reaction equipment, and stirring thoroughly to obtain premix A; S2. Add flame retardant to premix A, stir thoroughly, and evacuate to obtain a flame retardant transparent hot melt pressure sensitive adhesive product.

9. Use of the flame-retardant transparent hot-melt pressure-sensitive adhesive according to any one of claims 1 to 7 in optical cable bonding.

10. The use according to claim 9, characterized in that The optical cable bonding comprises the following steps: (1) performing corona treatment on at least part of the outer surface of the optical cable; (2) melting the flame-retardant transparent hot-melt pressure-sensitive adhesive and applying it to at least the area on the outer surface of the optical cable that has been subjected to the corona treatment, and cooling and shaping the adhesive; (3) Applying pressure to the optical cable, and bonding the optical cable to the target object by means of the flame-retardant transparent hot-melt pressure-sensitive adhesive.

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