Composition, hot melt adhesive and optical cable

Abstract

The present disclosure discloses a composition, a hot melt adhesive and an optical cable, and belongs to the technical field of optical cables. The composition comprises the following components in mass percentage: ethylene-vinyl acetate copolymer 5-60%, ethylene-acrylic acid copolymer 1-20%, styrene-ethylene-butylene-styrene block copolymer 1-50%, tackifier 5-40%, softening oil 5-30%, and hypophosphite flame retardant 5-30%. The hypophosphite flame retardant is selected from at least one of aluminum hypophosphite, zinc hypophosphite, iron hypophosphite, aluminum diethyl hypophosphite, aluminum methyl hypophosphite and aluminum propyl hypophosphite. The hot melt adhesive prepared from the composition can be used as a bonding layer of a concealed optical cable, ensuring that the bonding layer of the concealed optical cable has good transparency, flame retardance and yellowing resistance in addition to reliable bonding force.

Description

Technical Field

[0001] This disclosure relates to the field of optical cable technology, and particularly to compositions, hot melt adhesives and optical cables. Background Technology

[0002] Optical cables typically consist of optical fibers, a sheath covering the fibers, and an adhesive layer covering the sheath. The adhesive layer uses hot melt adhesive or double-sided tape to bond and secure the optical cable. Currently, indoor optical cables often use invisible optical cables, which aim for high transparency in both the sheath and adhesive layer to achieve invisibility and aesthetic appeal.

[0003] The hot melt adhesives used in the design of invisible optical cables typically include polyester thermoplastic polyurethane elastomers, rosin resins, ethylene-vinyl acetate, talc, UV-resistant additives, antioxidants, etc. However, although these hot melt adhesives have good transparency and adhesion, they have poor flame retardancy and are prone to yellowing during use, which is unfavorable for the application of the adhesive layer in invisible optical cables. Summary of the Invention

[0004] This disclosure provides a composition, hot melt adhesive, and optical cable, which can solve the technical problems existing in related technologies. The technical solution is shown below.

[0005] On one hand, a composition is provided, the composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 5%-40% tackifier, 5%-30% softening oil, and 5%-30% hypophosphite flame retardant, wherein the hypophosphite flame retardant is selected from at least one of aluminum hypophosphite, zinc hypophosphite, iron hypophosphite, aluminum diethylphosphite, aluminum methylphosphite, and aluminum propylphosphite.

[0006] The compositions provided in this disclosure can be used to prepare hot melt adhesives. By using ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, and styrene-ethylene-butene-styrene block copolymer as the base resin, the three components work synergistically in a specific ratio to impart good adhesion, flexibility, temperature resistance, and transparency to the hot melt adhesive. By adding specific amounts of tackifier and softening oil, the viscosity and flowability of the material are adjusted to obtain a hot melt adhesive with suitable viscosity and flowability, and the hot melt adhesive exhibits good processability after heating and melting. By adding specific amounts of hypophosphite flame retardants, the hypophosphite flame retardants being selected from at least one of aluminum hypophosphite, zinc hypophosphite, iron hypophosphite, aluminum diethylphosphite, aluminum methylphosphite, and aluminum propylphosphite, these hypophosphite flame retardants work synergistically with the base resin, tackifier, and softening oil to ensure that the hot melt adhesive maintains the above-mentioned properties, while also possessing good flame retardancy and resistance to yellowing. The hot melt adhesive formed by this composition can be used as the bonding layer for invisible optical cables, ensuring that the bonding layer of the invisible optical cable maintains reliable adhesion while also having good transparency, flame retardancy and yellowing resistance. Its high transparency is beneficial to the invisibility and aesthetic requirements of invisible optical cables, its high flame retardancy is beneficial to the flame retardancy requirements of invisible optical cables, and its strong yellowing resistance is beneficial to the invisible optical cable maintaining good transparency after long-term service, ensuring its service life.

[0007] In some possible implementations, the ethylene-vinyl acetate copolymer has a mass percentage of 20%-50%, the ethylene-acrylic acid copolymer has a mass percentage of 1%-5%, the styrene-ethylene-butene-styrene block copolymer has a mass percentage of 5%-20%, the tackifier has a mass percentage of 15%-30%, the softening oil has a mass percentage of 10%-20%, and the hypophosphite flame retardant has a mass percentage of 5%-25%.

[0008] In some possible implementations, the particle size of the hypophosphite flame retardant is less than or equal to 100 micrometers. By limiting the particle size of the flame retardant as described above, good transparency of the hot melt adhesive can be ensured. Furthermore, the large specific surface area of ​​the flame retardant facilitates enhanced physical adsorption with the base resin, thereby enhancing the flame retardant effect. Good dispersibility of the flame retardant enhances flame retardant uniformity and helps reduce the negative impact of the flame retardant on the basic properties of the base resin, thus better maintaining the original properties of the base resin while improving flame retardant performance.

[0009] In some possible implementations, the composition further includes ≤20% by weight of a phosphate ester flame retardant. Enhancing synergistic flame retardant effects and improving flame retardant efficiency can be achieved by combining the phosphate ester flame retardant with a hypophosphite flame retardant to form a composite flame retardant.

[0010] In some possible implementations, the phosphate ester flame retardant is selected from at least one of alkyl phosphate ester flame retardants, condensed phosphate ester flame retardants, phenyl phosphate ester flame retardants, cyclic phosphate esters, and dimethyl methyl phosphate.

[0011] In some possible implementations, the composition further includes ≤10% by weight of a silicone flame retardant. Silicone flame retardants exhibit good resistance to yellowing. By further increasing the amount of silicone flame retardant, the three flame retardants work synergistically, which not only further enhances the long-term resistance to yellowing of the hot melt adhesive, but also contributes to stronger flame retardant properties and thermal stability. Furthermore, the silicone flame retardant, based on its flexible characteristics, also improves the flexibility and processability of the hot melt adhesive.

[0012] In some possible implementations, the composition further includes ≤20% by weight of a charring agent, which includes at least one selected from pentaerythritol, dipentaerythritol, tripentaerythritol, and polyacrylate. Further increasing the amount of charring agent in the composition is more advantageous for enhancing the flame retardant properties of the hot melt adhesive, and, due to reduced oxidation reactions, can mitigate yellowing of the material to some extent. Moreover, the aforementioned types of charring agents have relatively stable structures and themselves possess good resistance to yellowing.

[0013] In some possible implementations, the composition further includes ≤20% polystyrene by weight. Polystyrene, as an optional matrix resin, not only enhances the structural stability of the hot melt adhesive to some extent but also adjusts its flowability and viscosity.

[0014] In some possible implementations, the composition further includes at least one of an antioxidant (≤5% by weight) and a UV-resistant additive (≤5% by weight). By further increasing the antioxidant in the composition, the oxidation reaction of the hot melt adhesive is inhibited, its service life is extended, and its performance is maintained stably. Further increasing the UV-resistant additive in the composition enhances the UV resistance of the hot melt adhesive, which is also beneficial for improving its resistance to yellowing.

[0015] In some possible implementations, the tackifier is selected from at least one of hydrogenated petroleum resin, hydrogenated rosin, and hydrogenated rosin glycerol ester.

[0016] In some possible implementations, the softening oil is selected from at least one of naphthenic oil, paraffin oil, and white oil.

[0017] On the other hand, a hot melt adhesive is provided, which is prepared using any of the compositions described above. The hot melt adhesive provided in this disclosure has all the advantages of the compositions involved above.

[0018] In another aspect, an optical cable is provided, the optical cable comprising: an optical fiber, a sheath covering the outer surface of the optical fiber, and an adhesive layer disposed outside the sheath, the adhesive layer being prepared using any of the compositions described above or the hot melt adhesives described above.

[0019] The optical cable disclosed in this embodiment is prepared using any of the aforementioned compositions for its adhesive layer, giving the adhesive layer at least the following advantages: good transparency, good flame retardancy, resistance to yellowing, and high adhesion. Therefore, while maintaining reliable adhesion, the high transparency of the optical cable's adhesive layer is beneficial for the invisibility and aesthetic requirements of stealth optical cables; its high flame retardancy is beneficial for the flame retardancy requirements of stealth optical cables; and its strong resistance to yellowing ensures that the stealth optical cable maintains good transparency even after long-term service, thus ensuring its service life.

[0020] In some possible implementations, the optical cable further includes a reinforcement member arranged in parallel with the optical fiber, and the sheath layer covers the outside of the optical fiber and the reinforcement member.

[0021] In some possible implementations, the optical cable further includes a tight sleeve that tightly covers the outside of the optical fiber.

[0022] In some possible implementations, the adhesive layer has at least the following physical properties: light transmittance ≥ 50% / 0.1mm, color difference ≤ 6 under 500h UV irradiation conditions, and initial adhesive force ≥ 1.2N / mm. Attached Figure Description

[0023] Figure 1 A schematic cross-sectional view of a first exemplary optical cable provided in an embodiment of this disclosure;

[0024] Figure 2 A schematic cross-sectional view of a second exemplary optical cable provided in an embodiment of this disclosure;

[0025] Figure 3 A schematic cross-sectional view of a third exemplary optical cable provided in this embodiment of the disclosure;

[0026] Figure 4 A schematic cross-sectional view of the fourth exemplary optical cable provided in this embodiment of the disclosure;

[0027] Figure 5 This is a cross-sectional schematic diagram of a fifth exemplary optical cable provided in an embodiment of this disclosure.

[0028] The reference numerals in the attached figures represent:

[0029] 100, Optical fiber; 200, Sheath layer; 300, Adhesive layer; 400, Reinforcing member; 500, Tight sleeve. Detailed Implementation

[0030] Optical cables are communication lines used in optical communication to achieve stable transmission of optical signals. An optical cable typically consists of optical fibers, a sheath covering the optical fibers, and an adhesive layer covering the sheath. The adhesive layer uses hot melt adhesive or double-sided tape to bond and fix the optical cable. Optical cables can be classified according to their application scenario into outdoor optical cables, drop cables, and indoor optical cables. Outdoor optical cables are typically used in backbone transmission networks and distribution transmission networks, and are constructed through methods such as direct burial, duct laying, overhead laying, and underwater laying. Therefore, outdoor optical cables have advantages such as excellent mechanical properties and strong corrosion and aging resistance. Drop cables are used in Fiber to the Home (FTTH) scenarios. One end of the drop cable is outdoors, and the other end is inside the building. Therefore, drop cables typically have excellent mechanical properties, corrosion and aging resistance, and good flame retardant properties to meet the requirements of relevant flame retardant regulations (IEC 60332-1-2 or EN 50575). Indoor optical cables are used in Fiber to the Room (FTTR) scenarios to enable communication between communication equipment and terminal devices within a building. Because indoor optical cables are laid indoors, their requirements for mechanical properties (e.g., tensile and compressive strength), aging resistance, and environmental stability are relatively lower than those for outdoor and drop cables. However, compared to the other two, indoor optical cables have higher requirements for ease of installation, aesthetics, and flame retardancy. Therefore, invisible optical cables have emerged to meet these needs.

[0031] The sheath and adhesive layer of invisible optical cables have high transparency to achieve the requirements of invisibility and aesthetics. The hot melt adhesives designed for invisible optical cables typically include polyester thermoplastic polyurethane elastomers, rosin resin, ethylene-vinyl acetate, talc, anti-UV additives, antioxidants, etc. However, although these hot melt adhesives have good transparency and adhesion, they have poor flame retardancy and are prone to yellowing during use, which is not conducive to the application of adhesive layers in invisible optical cables.

[0032] Therefore, it is necessary to provide a new type of hot melt adhesive material that, while maintaining high adhesion, also possesses high transparency and flame retardancy, and exhibits excellent resistance to yellowing under long-term service conditions, thereby meeting the requirements for the efficient deployment of stealth optical cables.

[0033] To address the technical problems existing in related technologies, this disclosure provides a composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 5%-40% tackifier, 5%-30% softening oil, and 5%-30% hypophosphite flame retardant. The hypophosphite flame retardant is selected from at least one of aluminum hypophosphite, zinc hypophosphite, iron hypophosphite, aluminum diethylphosphite, aluminum methylphosphite, and aluminum propylphosphite.

[0034] The compositions provided in this disclosure can be used to prepare hot melt adhesives. By using ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, and styrene-ethylene-butene-styrene block copolymer as the base resin, the three components work synergistically in a specific ratio to impart good adhesion, flexibility, temperature resistance, and transparency to the hot melt adhesive. By adding specific amounts of tackifier and softening oil, the viscosity and flowability of the material are adjusted to obtain a hot melt adhesive with suitable viscosity and flowability, and the hot melt adhesive exhibits good processability after heating and melting. By adding specific amounts of hypophosphite flame retardants, the hypophosphite flame retardants being selected from at least one of aluminum hypophosphite, zinc hypophosphite, iron hypophosphite, aluminum diethylphosphite, aluminum methylphosphite, and aluminum propylphosphite, these hypophosphite flame retardants work synergistically with the base resin, tackifier, and softening oil to ensure that the hot melt adhesive maintains the above-mentioned properties, while also possessing good flame retardancy and resistance to yellowing. The hot melt adhesive formed by this composition can be used as the bonding layer for invisible optical cables, ensuring that the bonding layer of the invisible optical cable maintains reliable adhesion while also having good transparency, flame retardancy and yellowing resistance. Its high transparency is beneficial to the invisibility and aesthetic requirements of invisible optical cables, its high flame retardancy is beneficial to the flame retardancy requirements of invisible optical cables, and its strong yellowing resistance is beneficial to the invisible optical cable maintaining good transparency after long-term service, ensuring its service life.

[0035] The composition and function of each component in the composition are illustrated below by way of example.

[0036] Ethylene-vinyl acetate copolymer (EVA) has good flexibility and adhesion to a variety of materials. In addition, ethylene-vinyl acetate copolymer has good temperature resistance, which is beneficial for broadening the operating temperature range of hot melt adhesives.

[0037] The higher the vinyl acetate (VA) content in the ethylene-vinyl acetate copolymer, the better its elasticity, flexibility, and viscosity. It can make the mass percentage of vinyl acetate in the ethylene-vinyl acetate copolymer ≥28%, and further, it can make the melt index of the ethylene-vinyl acetate copolymer ≥200 (test conditions are 190℃, 2.16kg load), and make the Vicat softening point of the ethylene-vinyl acetate copolymer 35℃-55℃, so as to achieve the purpose of enhancing its effects.

[0038] In this embodiment of the disclosure, the ethylene-vinyl acetate copolymer accounts for 5%-60% by mass in the composition, and more particularly, 20%-50%. This can be any of the following values ​​or any range of two values: 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%.

[0039] 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%,

[0040] 60%, etc.

[0041] Ethylene-acrylic acid copolymer (EAA), due to its polar acrylic groups, exhibits excellent adhesion to a variety of materials, especially polar materials. Blending EAA with ethylene-vinyl acetate copolymer and styrene-ethylene-butene-styrene block copolymer expands the bonding range of hot melt adhesives, making them suitable for bonding various types of materials. Furthermore, EAA also possesses good temperature resistance and prevents hypophosphite flame retardants, such as aluminum diethylphosphinate, from turning green, thus improving the yellowing resistance of hot melt adhesives.

[0042] In some examples, the ethylene-acrylic acid copolymer can be made to meet at least one of the following physical properties to enhance its effect: the mass percentage of acrylic acid segments in the ethylene-acrylic acid copolymer is ≥10%, the melt index of the ethylene-acrylic acid copolymer is ≥12 (test conditions are 125°C and 2.16 kg load), and the Vicat softening point of the ethylene-acrylic acid copolymer is 35°C-55°C.

[0043] In this embodiment of the disclosure, the ethylene-acrylic acid copolymer is present in the composition at a mass percentage of 1%-20%, and more preferably 1%-5%, which may be any of the following values ​​or any range of two values: 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0044] Styrene-ethylene-butene-styrene block copolymer (SEBS) has excellent flexibility and elastic recovery. By adding styrene-ethylene-butene-styrene block copolymer to hot melt adhesives, the flexibility of the hot melt adhesives can be improved, so that they can maintain good bonding performance and are not easy to break under different usage environments, such as bending and stretching.

[0045] In some examples, the styrene-ethylene-butene-styrene block copolymer can be made to meet at least one of the following physical properties to enhance its effect: the styrene mass percentage in the styrene-ethylene-butene-styrene block copolymer is 13%-32%, and the melt index of the styrene-ethylene-butene-styrene block copolymer is ≥3 (test conditions are 250°C and 5kg load).

[0046] In this embodiment of the disclosure, the styrene-ethylene-butene-styrene block copolymer is present in a mass percentage of 1%-50% in the composition, and may further be 5%-20%, which may be any of the following values ​​or any range of two values: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc.

[0047] Tackifiers are used to increase the viscosity of hot melt adhesives, while softening oils adjust the flowability of hot melt adhesives, allowing them to be better applied to material surfaces after melting. The specific amounts of tackifiers and softening oils can be adjusted according to the specific production process and bonding requirements to obtain hot melt adhesives with suitable viscosity and flowability.

[0048] In this embodiment of the disclosure, the tackifier has a mass percentage of 5%-40% in the composition, and more preferably 15%-30%, which can be any of the following values ​​or any range of two values: 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, etc.

[0049] For any of the compositions mentioned above, suitable tackifiers are selected from at least one of hydrogenated petroleum resins, hydrogenated rosin, and hydrogenated rosin glycerides. For example, the tackifier may be a hydrogenated petroleum resin, specifically a tackifying hydrogenated petroleum resin, which has a high acid value and polarity, enabling it to interact with polar groups on the surface of the adherend, thereby enhancing adhesion. For example, the hydrogenated petroleum resin may meet the following parameters: a ring and ball softening point of 100°C to 115°C, and a viscosity of 180 mPa·s to 420 mPa·s (190°C).

[0050] In this embodiment of the disclosure, the softening oil has a mass percentage of 5%-30% in the composition, and may further be 10%-20%, which may be any of the following values ​​or any range of two values: 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc.

[0051] For any of the compositions mentioned above, some suitable softening oils are selected from at least one of naphthenic oil, paraffinic oil, and white oil. For example, naphthenic oil can be used as the softening oil, and the naphthenic oil has a mass percentage of 260% of naphthenic alkyl groups and a mass percentage of 12% of aromatics, and the viscosity of the naphthenic oil is 0.3 mPa·s-0.7 mPa·s.

[0052] In this embodiment of the disclosure, the mass percentage of the hypophosphite flame retardant in the composition is 5%-30%, and more preferably 5%-25%, which can be any of the following values ​​or any range of two values: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, etc.

[0053] In some examples, embodiments of this disclosure provide a composition wherein the ethylene-vinyl acetate copolymer is 20%-50% by mass, the ethylene-acrylic acid copolymer is 1%-5% by mass, the styrene-ethylene-butene-styrene block copolymer is 5%-20% by mass, the tackifier is 15%-30% by mass, the softening oil is 10%-20% by mass, and the hypophosphite flame retardant is 5%-25% by mass (more preferably 15%-25%).

[0054] The compositions disclosed herein allow for the particle size of the flame retardants (including hypophosphite flame retardants) to be in the micrometer and nanometer range. For example, the particle size of the hypophosphite flame retardants may be less than or equal to 100 micrometers, further less than or equal to 10 micrometers, less than or equal to 5 micrometers, less than or equal to 1 micrometer, etc. By limiting the particle size of the flame retardants as described above, good transparency of the hot melt adhesive can be ensured. Furthermore, the large specific surface area of ​​the flame retardants facilitates enhanced physical adsorption with the matrix resin, thereby enhancing the flame retardant effect. Good dispersibility of the flame retardants enhances flame retardant uniformity and helps reduce the negative impact of the flame retardants on the basic properties of the matrix resin, thus better maintaining the original properties of the matrix resin while improving flame retardant performance.

[0055] In some examples, embodiments of this disclosure provide a composition comprising the following components in weight percentages: 30%-50% ethylene-vinyl acetate copolymer, 1%-5% ethylene-acrylic acid copolymer, 5%-20% styrene-ethylene-butene-styrene block copolymer, 15%-30% tackifier, 10%-20% softening oil, and 15%-25% hypophosphite flame retardant, wherein the hypophosphite flame retardant has a particle size of less than or equal to 100 micrometers.

[0056] In some embodiments, the compositions provided in this disclosure further include ≤20% by weight of a phosphate ester flame retardant. For example, the mass percentage of the phosphate ester flame retardant in the composition may further be ≤10%, 5%, etc., which may be any of the following values ​​or any range of two values: 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0057] By combining phosphate ester flame retardants with hypophosphite flame retardants to form composite flame retardants, enhanced synergistic flame retardant effects can be achieved, thereby improving flame retardant efficiency.

[0058] In some examples, the content of phosphate ester flame retardants can be lower than that of hypophosphite flame retardants. For example, the mass ratio of phosphate ester flame retardants to hypophosphite flame retardants is 1:1.5-3.5, including but not limited to: 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, etc., to ensure the excellent flame retardant performance of the composite flame retardant while preventing any impact on other basic properties of the hot melt adhesive.

[0059] Some phosphate ester flame retardants applicable to the embodiments of this disclosure may be alkyl phosphate ester flame retardants, condensed phosphate ester flame retardants, phenyl phosphate ester flame retardants, cyclic phosphate esters, dimethyl methyl phosphate, etc., wherein alkyl phosphate ester flame retardants may be trimethyl phosphate, triethyl phosphate, tributyl phosphate, etc., condensed phosphate ester flame retardants may be, for example, bisphenol A bis(diphenyl phosphate), resorcinol bis(diphenyl phosphate), etc., and phenyl phosphate ester flame retardants may be, for example, triphenyl phosphate, resorcinol diphenyl diphosphate, etc.

[0060] In some examples, embodiments of this disclosure provide a composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 5%-40% tackifier, 5%-30% softening oil, 5%-30% hypophosphite flame retardant, and 1%-20% phosphate ester flame retardant.

[0061] Furthermore, the mass percentage of the ethylene-vinyl acetate copolymer is 30%-50%, the mass percentage of the ethylene-acrylic acid copolymer is 1%-5%, the mass percentage of the styrene-ethylene-butene-styrene block copolymer is 5%-20%, the mass percentage of the tackifier is 15%-30%, the mass percentage of the softening oil is 10%-20%, the mass percentage of the hypophosphite flame retardant is 15%-25%, and the mass percentage of the phosphate ester flame retardant is 1%-10%.

[0062] In some embodiments, the composition further includes ≤10% by weight of a silicone flame retardant, which has good resistance to yellowing. By further increasing the amount of silicone flame retardant, the three flame retardants work synergistically, which is not only more beneficial to improving the long-term resistance to yellowing of the hot melt adhesive, but also beneficial to making the hot melt adhesive exhibit stronger flame retardant properties and thermal stability. In addition, the silicone flame retardant, based on its flexible characteristics, is also beneficial to improving the flexibility and processing properties of the hot melt adhesive.

[0063] Silicone flame retardants can be in the micron or nanometer size range, and can be siloxane flame retardants (e.g., methyl silicone oil, phenyl silicone oil, hydroxyl silicone oil, etc.), fluorosilane flame retardants, cage-like octaphenylsilsesquioxanes (POPS), dimethyldiphenylpolysiloxanes, silicone polymers, etc. Furthermore, the mass percentage of the silicone flame retardant is 1%-5%, for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc., to minimize the impact of the silicone flame retardant on the adhesive properties of the hot melt adhesive.

[0064] In some examples, embodiments of this disclosure provide a composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 5%-40% tackifier, 5%-30% softening oil, 5%-30% hypophosphite flame retardant, and 1%-10% silicone flame retardant. Further, the mass percentages of the ethylene-vinyl acetate copolymer are 30%-50%, the ethylene-acrylic acid copolymer is 1%-5%, the styrene-ethylene-butene-styrene block copolymer is 5%-20%, the tackifier is 15%-30%, the softening oil is 10%-20%, the hypophosphite flame retardant is 15%-25%, and the silicone flame retardant is 1%-5%.

[0065] In some examples, embodiments of this disclosure provide a composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 5%-40% tackifier, 5%-30% softening oil, 5%-30% hypophosphite flame retardant, 1%-20% phosphate ester flame retardant, and 1%-10% silicone flame retardant. Further, the mass percentages of the ethylene-vinyl acetate copolymer are 30%-50%, the ethylene-acrylic acid copolymer is 1%-5%, the styrene-ethylene-butene-styrene block copolymer is 5%-20%, the tackifier is 15%-30%, the softening oil is 10%-20%, the hypophosphite flame retardant is 15%-25%, the phosphate ester flame retardant is 1%-10%, and the silicone flame retardant is 1%-5%.

[0066] In some embodiments, for any of the compositions mentioned above, the composition further includes ≤20% by weight of a charring agent, which includes at least one of pentaerythritol, dipentaerythritol, tripentaerythritol, and polyacrylate, and the polyacrylate may further include polymethyl acrylate, polyethyl acrylate, polybutyl acrylate, polymethyl methacrylate, etc.

[0067] Charring agents can form carbonization products during combustion. The carbon layer formed by these products has good heat insulation and oxygen barrier properties. Further increasing the amount of charring agent in the composition is more beneficial for enhancing the flame retardant properties of hot melt adhesives. Moreover, by reducing the occurrence of oxidation reactions, the yellowing of materials can be mitigated to some extent. Furthermore, the structures of the aforementioned types of charring agents are relatively stable, and they themselves also have good resistance to yellowing.

[0068] By limiting the content of the charring agent to ≤20%, and further, the mass percentage of the charring agent to ≤10%, such as 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 7%, 8%, 9%, 10%, etc., the influence of the charring agent on the bonding performance of the hot melt adhesive is kept low.

[0069] In some examples, embodiments of this disclosure provide a composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 5%-40% tackifier, 5%-30% softening oil, 5%-30% hypophosphite flame retardant, and 1%-20% charring agent. Further, the mass percentages of the ethylene-vinyl acetate copolymer are 30%-50%, the ethylene-acrylic acid copolymer is 1%-5%, the styrene-ethylene-butene-styrene block copolymer is 5%-20%, the tackifier is 15%-30%, the softening oil is 10%-20%, the hypophosphite flame retardant is 15%-25%, and the charring agent is 1%-10%.

[0070] In some examples, embodiments of this disclosure provide a composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 5%-40% tackifier, 5%-30% softening oil, 5%-30% hypophosphite flame retardant, 1%-10% silicone flame retardant, and 1%-20% charring agent. Further, the mass percentages of the ethylene-vinyl acetate copolymer are 30%-50%, the ethylene-acrylic acid copolymer is 1%-5%, the styrene-ethylene-butene-styrene block copolymer is 5%-20%, the tackifier is 15%-30%, the softening oil is 10%-20%, the hypophosphite flame retardant is 15%-25%, the silicone flame retardant is 1%-5%, and the charring agent is 1%-10%.

[0071] In some examples, embodiments of this disclosure provide a composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 5%-40% tackifier, 5%-30% softening oil, 5%-30% hypophosphite flame retardant, 1%-20% phosphate ester flame retardant, 1%-10% silicone flame retardant, and 1%-20% charring agent. Furthermore, the mass percentage of the ethylene-vinyl acetate copolymer is 30%-50%, the mass percentage of the ethylene-acrylic acid copolymer is 1%-5%, the mass percentage of the styrene-ethylene-butene-styrene block copolymer is 5%-20%, the mass percentage of the tackifier is 15%-30%, the mass percentage of the softening oil is 10%-20%, the mass percentage of the hypophosphite flame retardant is 15%-25%, the mass percentage of the phosphate ester flame retardant is 1%-10%, the mass percentage of the organosilicon flame retardant is 1%-5%, and the mass percentage of the charring agent is 1%-10%.

[0072] In some embodiments, for any of the compositions mentioned above, the composition further includes ≤20% by mass of polystyrene, and the mass percentage of polystyrene may further be ≤10%. Polystyrene, as an optional matrix resin, can not only improve the structural stability of the hot melt adhesive to a certain extent, but also adjust the flowability and viscosity of the hot melt adhesive.

[0073] In some examples, embodiments of this disclosure provide a composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 1%-20% polystyrene, 5%-40% tackifier, 5%-30% softening oil, 5%-30% hypophosphite flame retardant, and 1%-20% charring agent. Further, the weight percentages of the ethylene-vinyl acetate copolymer are 30%-50%, the ethylene-acrylic acid copolymer is 1%-5%, the styrene-ethylene-butene-styrene block copolymer is 5%-20%, the polystyrene is 1%-10%, the tackifier is 15%-30%, the softening oil is 10%-20%, the hypophosphite flame retardant is 15%-25%, and the charring agent is 1%-10%.

[0074] In some examples, embodiments of this disclosure provide a composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 1%-20% polystyrene, 5%-40% tackifier, 5%-30% softening oil, 5%-30% hypophosphite flame retardant, 1%-10% silicone flame retardant, and 1%-20% charring agent. Furthermore, the mass percentage of the ethylene-vinyl acetate copolymer is 30%-50%, the mass percentage of the ethylene-acrylic acid copolymer is 1%-5%, the mass percentage of the styrene-ethylene-butene-styrene block copolymer is 5%-20%, the mass percentage of polystyrene is 1%-10%, the mass percentage of the tackifier is 15%-30%, the mass percentage of the softening oil is 10%-20%, the mass percentage of the hypophosphite flame retardant is 15%-25%, the mass percentage of the organosilicon flame retardant is 1%-5%, and the mass percentage of the charring agent is 1%-10%.

[0075] In some examples, embodiments of this disclosure provide a composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 1%-20% polystyrene, 5%-40% tackifier, 5%-30% softening oil, 5%-30% hypophosphite flame retardant, 1%-20% phosphate ester flame retardant, 1%-10% silicone flame retardant, and 1%-20% charring agent. Furthermore, the mass percentage of the ethylene-vinyl acetate copolymer is 30%-50%, the mass percentage of the ethylene-acrylic acid copolymer is 1%-5%, the mass percentage of the styrene-ethylene-butene-styrene block copolymer is 5%-20%, the mass percentage of polystyrene is 1%-10%, the mass percentage of the tackifier is 15%-30%, the mass percentage of the softening oil is 10%-20%, the mass percentage of the hypophosphite flame retardant is 15%-25%, the mass percentage of the phosphate ester flame retardant is 1%-10%, the mass percentage of the organosilicon flame retardant is 1%-5%, and the mass percentage of the charring agent is 1%-10%.

[0076] In some embodiments, for any of the compositions mentioned above, the composition further includes at least one of an antioxidant and a UV-resistant additive at a mass percentage of ≤5%. For example, only an antioxidant may be added, only a UV-resistant additive may be added, or both an antioxidant and a UV-resistant additive may be added simultaneously.

[0077] In some examples, the antioxidant can be a hindered phenolic, hindered amine, or phosphite antioxidant, such as at least one of antioxidant 168, antioxidant 1010, antioxidant 1076, antioxidant 1098, antioxidant 3114, antioxidant 164, and antioxidant 264. By further increasing the amount of antioxidant in the composition, the oxidation reaction of the hot melt adhesive is inhibited, its service life is extended, and its performance is maintained stably. The mass percentage of the antioxidant can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0078] In some examples, the UV-resistant additives can be light stabilizers, UV absorbers, etc. For example, light stabilizers can be hindered amine light stabilizers, etc., and UV absorbers can be benzophenone UV absorbers, benzotriazole UV absorbers, etc. By further adding UV-resistant additives to the composition, the UV resistance of the hot melt adhesive can be enhanced, which is more beneficial for enhancing its yellowing resistance.

[0079] In some examples, the mass percentage of the UV-resistant additive can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0080] In some examples, embodiments of this disclosure provide a composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 1%-20% polystyrene, 5%-40% tackifier, 5%-30% softening oil, 5%-30% hypophosphite flame retardant, 1%-20% charring agent, 1%-5% antioxidant, and 1%-5% UV resistant additive.

[0081] In some examples, embodiments of this disclosure provide a composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 1%-20% polystyrene, 5%-40% tackifier, 5%-30% softening oil, 5%-30% hypophosphite flame retardant, 1%-10% silicone flame retardant, 1%-20% charring agent, 1%-5% antioxidant, and 1%-5% UV resistant additive.

[0082] In some examples, embodiments of this disclosure provide a composition comprising the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 1%-20% polystyrene, 5%-40% tackifier, 5%-30% softening oil, 5%-30% hypophosphite flame retardant, 1%-20% phosphate ester flame retardant, 1%-10% silicone flame retardant, 1%-20% charring agent, 1%-5% antioxidant, and 1%-5% UV resistant additive.

[0083] On the other hand, embodiments of this disclosure also provide a hot melt adhesive prepared using any of the compositions described above. The hot melt adhesive provided by embodiments of this disclosure possesses all the advantages of the compositions involved above.

[0084] Tests have shown that the hot melt adhesive prepared based on the composition provided in the embodiments of this disclosure has at least the following effects: the hot melt adhesive meets the V2 flame retardancy standard (3mm thickness); the transparency of the hot melt adhesive is ≥50% (0.1mm thickness), where transparency refers to light transmittance; the initial adhesive strength (adhesive medium is steel plate and PET, 90-degree peel force) of the hot melt adhesive is ≥0.4N / mm. After UV aging (ISO 4892-2 cycle 5) for 500 hours, the hot melt adhesive shows no visible yellowing and a color difference ≤6; after aging at high temperature and high humidity (65℃, 95% humidity) for 500 hours, the hot melt adhesive shows no visible yellowing and a color difference ≤6.

[0085] Furthermore, embodiments of this disclosure provide an optical cable, as shown in the attached... Figure 1 -Appendix Figure 5 As shown, the optical cable includes: an optical fiber 100, a sheath layer 200 covering the outside of the optical fiber 100, and an adhesive layer 300 disposed outside the sheath layer 200, wherein the adhesive layer 300 is prepared using any of the compositions or hot melt adhesives mentioned above.

[0086] The adhesive layer 300 can be disposed on a portion of the outer surface of the sheath layer 200, for example, on one side surface of the sheath layer 200, or it can cover the outside of the sheath layer 200. Based on the adhesive layer 300, the optical cable can be quickly and reliably fixed, for example, fixed to a wall.

[0087] The optical cable disclosed in this embodiment is prepared using any of the aforementioned compositions for its adhesive layer 300, giving the adhesive layer at least the following advantages: good transparency, good flame retardancy, resistance to yellowing, and high adhesion. Therefore, while maintaining reliable adhesion, the high transparency of the optical cable's adhesive layer is beneficial for the invisibility and aesthetic requirements of the stealth optical cable; its high flame retardancy is beneficial for the flame retardancy requirements of the stealth optical cable; and its strong resistance to yellowing is beneficial for the stealth optical cable to maintain good transparency even after long-term service, ensuring its service life.

[0088] In some examples, such as the attached Figure 1 -Appendix Figure 5 As shown, the optical cable also includes a reinforcing member 400, which is arranged in parallel with the optical fiber 100. A sheath layer 200 covers the outside of the optical fiber 100 and the reinforcing member 400. The reinforcing member 400 can be, for example, steel wire, glass fiber reinforced plastic, aramid fiber, polyester fiber, etc. The reinforcing member 400 protects the optical fiber 100 from mechanical stress (such as tension, bending, flattening, etc.) and ensures its integrity and performance during installation and use.

[0089] In the optical cable disclosed in this embodiment, the number of optical fibers 100 can be one or more, and the number of reinforcing members 400 can be multiple. The reinforcing members 400 are arranged in parallel with the optical fibers 100, and both are extruded and formed synchronously with the sheath material.

[0090] In some examples, such as the attached Figure 4 As shown, the optical cable also includes a tight sleeve 500, which tightly wraps around the outside of the optical fiber 100. The optical fiber 100 is tightly wrapped inside the tight sleeve 500, which provides physical and environmental protection, ensuring that the optical fiber 100 is not easily damaged during installation and use.

[0091] Based on the optical cable solutions mentioned above, optical cables can be formed by combining any two or more of the above solutions to create different types of optical cables.

[0092] For any of the optical cables mentioned above in the embodiments of this disclosure, the adhesive layer 300 has at least the following physical properties: light transmittance ≥ 50% / 0.1mm, color difference ≤ 6 under 500h UV irradiation conditions, and initial adhesive force ≥ 1.2N / mm. It can be seen that this is of great significance for enhancing the working reliability of the stealth optical cable.

[0093] The performance of the adhesive layer prepared based on the above composition was tested according to the embodiments of this disclosure, and the test results are listed in Table 1.

[0094] Table 1

[0095]

[0096] In summary, the optical cable prepared based on the composition provided in the embodiments of this disclosure has the following advantages: (1) Easy deployment: it can be torn and glued immediately, and can be deployed immediately after tearing. (2) High adhesion: it can be reliably bonded at temperatures ranging from 5℃ to 60℃. (3) High reliability: it exhibits strong tensile strength and is halogen-free and flame-retardant. (4) High aesthetics: the material has high transparency and is resistant to yellowing.

[0097] Exemplary embodiments of this disclosure will now be described in more detail. While exemplary embodiments of this disclosure are described below, it should be understood that this disclosure can be implemented in various forms and should not be limited to the embodiments set forth herein. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with techniques or conditions described in the literature in the art or according to product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0098] It should be noted that in the compositions involved in the following embodiments, the mesh size of the aluminum diethylphosphonate is set to ≥8000 mesh. The ethylene-vinyl acetate copolymer (EVA) involved has a VA content of 28% by mass, a melt index of 300 (test conditions: 190℃, 2.16kg load), and a Vicat softening point of 40℃. The ethylene-acrylic acid copolymer (EAA) involved has an AA content of 20.5% by mass, a melt index of 12 (test conditions: 125℃, 2.16kg load), and a Vicat softening point of 50℃. The styrene-ethylene-butene-styrene block copolymer (SEBS) involved has a styrene segment content of 30% by mass, and a melt index of 5 (test conditions: 250℃, 5kg load). The polystyrene involved has a strength of 40MPa, an elongation at break of 3%, a melt index of 7g / 10min (200℃ / 5kg), and a glass transition temperature of 95℃. The hydrogenated petroleum resin involved meets the following requirements: a ring and ball softening point of 100℃ and a viscosity of 200 mPa·s (190℃). The naphthenic oil involved meets the following requirements: a naphthenic alkyl content ≥60% by mass, an aromatic content ≤12% by mass, and a viscosity of 0.5 mPa·s. The dimethyl diphenyl polysiloxane involved is GENIOPLAST Gum. The polyacrylate involved is AX8900.

[0099] Examples 1-6

[0100] Examples 1-6 each provide a composition, the composition of which is shown in Tables 2-7 respectively.

[0101] Table 2

[0102]

[0103] Table 3

[0104]

[0105] Table 4

[0106]

[0107]

[0108] Table 5

[0109]

[0110] Table 6

[0111]

[0112] Table 7

[0113]

[0114] Test case

[0115] The compositions provided in Examples 1-6 were mixed and molded to form hot melt adhesive samples. The performance of each hot melt adhesive sample was tested based on the test methods and standards described in Table 1 of this disclosure. The test results are shown in Table 8.

[0116] Table 8

[0117]

[0118] In summary, the hot melt adhesive prepared based on the composition provided in the embodiments of this disclosure not only meets the requirements for adhesion, but also has high transparency, resistance to yellowing, and flame retardancy.

[0119] The above description is only for the purpose of enabling those skilled in the art to understand the technical solutions disclosed herein, and is not intended to limit the scope of this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A composition, characterized in that, The composition comprises the following components in weight percentages: 5%-60% ethylene-vinyl acetate copolymer, 1%-20% ethylene-acrylic acid copolymer, 1%-50% styrene-ethylene-butene-styrene block copolymer, 5%-40% tackifier, 5%-30% softening oil, and 5%-30% hypophosphite flame retardant; The hypophosphite flame retardant is selected from at least one of aluminum hypophosphite, zinc hypophosphite, iron hypophosphite, aluminum diethylphosphite, aluminum methylphosphite, and aluminum propylphosphite.

2. The composition according to claim 1, characterized in that, The ethylene-vinyl acetate copolymer has a mass percentage of 20%-50%, the ethylene-acrylic acid copolymer has a mass percentage of 1%-5%, the styrene-ethylene-butene-styrene block copolymer has a mass percentage of 5%-20%, the tackifier has a mass percentage of 15%-30%, the softening oil has a mass percentage of 10%-20%, and the hypophosphite flame retardant has a mass percentage of 5%-25%.

3. The composition according to claim 1, characterized in that, The particle size of the hypophosphite flame retardant is less than or equal to 100 micrometers.

4. The composition according to claim 1, characterized in that, The composition also includes ≤20% by weight of a phosphate ester flame retardant.

5. The composition according to claim 4, characterized in that, The phosphate ester flame retardant is selected from at least one of alkyl phosphate ester flame retardants, condensed phosphate ester flame retardants, phenyl phosphate ester flame retardants, cyclic phosphate esters, and dimethyl methyl phosphate.

6. The composition according to claim 1, characterized in that, The composition also includes ≤10% by weight of an organosilicon flame retardant.

7. The composition according to claim 1, characterized in that, The composition further includes ≤20% by weight of a charring agent, wherein the charring agent includes at least one of pentaerythritol, dipentaerythritol, tripentaerythritol, and polyacrylate.

8. The composition according to any one of claims 1-7, characterized in that, The composition also includes ≤20% polystyrene by weight.

9. The composition according to any one of claims 1-8, characterized in that, The composition further includes at least one of an antioxidant and an anti-UV additive, with a mass percentage of ≤5%.

10. The composition according to any one of claims 1-9, characterized in that, The tackifier is selected from at least one of hydrogenated petroleum resin, hydrogenated rosin, and hydrogenated rosin glycerol ester.

11. The composition according to any one of claims 1-10, characterized in that, The softening oil is selected from at least one of naphthenic oil, paraffin oil, and white oil.

12. A hot melt adhesive, characterized in that, The hot melt adhesive is prepared using the composition according to any one of claims 1-11.

13. An optical cable, characterized in that, The optical cable includes: an optical fiber, a sheath covering the outside of the optical fiber, and an adhesive layer disposed outside the sheath, wherein the adhesive layer is prepared using the composition according to any one of claims 1-11 or the hot melt adhesive according to claim 12.

14. The optical cable according to claim 13, characterized in that, The optical cable also includes a reinforcing member, which is arranged in parallel with the optical fiber, and the sheath layer covers the outside of the optical fiber and the reinforcing member.

15. The optical cable according to any one of claims 13-14, characterized in that, The optical cable also includes a tight sleeve, which tightly covers the outside of the optical fiber.

16. The optical cable according to any one of claims 13-15, characterized in that, The adhesive layer has at least the following physical properties: light transmittance ≥ 50% / 0.1mm, color difference ≤ 6 under 500h UV irradiation conditions, and initial adhesive force ≥ 1.2N / mm.

Images