Material for flame-retardant optical cable transmission equipment and preparation method thereof

Abstract

The invention relates to the field of optical communication equipment, in particular to a material for flame-retardant optical cable transmission equipment and a preparation method of the material. In the application, the combination of the aromatic polyester polyol and the aliphatic polyester polyol is used as the raw material of the polyurethane, so that high moisture resistance is provided while good mechanical properties are ensured on the whole, and experiments show that the material can keep good rebound resilience, tensile property and strength in a high-humidity environment, so that the tensile strength of the material is improved, and the service life of the material is prolonged. Good application prospects are realized.

Description

Technical Field

[0001] The present application relates to the field of optical communication equipment, and in particular to a material for flame-retardant optical cable transmission equipment and a preparation method thereof. Background Art

[0002] In optical cable transmission equipment, thermoplastic flame-retardant packaging materials, led by polyurethane, are an important material. They protect the optical communication materials therein by forming a system with both high strength and high elasticity.

[0003] In order to improve the overall toughness and strength, polyurethane usually uses polyester type. Polyester type polyurethane has a better surface in terms of tensile properties, and compared with polyether type, polyester type has better cohesion and can provide better protection. However, polyester polyols are prone to hydrolysis in long-term high humidity environments, which can easily lead to poor weather resistance of the above materials in high humidity environments. Long-term use may cause its mechanical strength to weaken, which can easily affect the internal optical fiber materials. Summary of the invention

[0004] The present application mainly provides a material for optical cable transmission equipment with good flame retardancy, which not only takes into account flame retardancy and mechanical strength, but also can maintain good weather resistance in a humid environment.

[0005] First, the present application relates to a material for flame-retardant optical cable transmission equipment, which comprises the following components in parts by mass:

[0006] Polyurethane 100 parts

[0007] 20-30 parts of fluorinated polyolefin

[0008] Low density linear polyethylene 8-16 parts

[0009] Glass fiber 5-10 parts

[0010] Antioxidant 0.1-1 part

[0011] Compatibilizer 2-5 parts

[0012] Phosphorus-containing flame retardant 5-10 parts

[0013] The polyurethane is obtained by polymerization of polyester polyol and isocyanate, wherein the polyester polyol contains aromatic polyester polyol accounting for more than 20 to 40% of the mass of the polyester polyol; the polyurethane has an organosilicon end-capping structure;

[0014] The fluorine-containing polyolefin is polytetrafluoroethylene or polyvinylidene fluoride.

[0015] In addition, the phosphorus-containing flame retardant may be polyphosphate, and / or the compatibilizer may be maleic anhydride grafted polyethylene.

[0016] In the above scheme, polyamide is used as the main material to form an elastic material, and improvements are made on the basis of polyamide, with the goal of improving the overall flame retardancy, moisture resistance and mechanical properties. Among them, on the basis of polyurethane, by adding fluorinated polyolefins and low-density linear polyethylene, the overall water barrier performance and tolerance performance can be greatly improved. Under high humidity conditions, when water molecules penetrate into the plastic system, on the one hand, fluorine atoms can prevent the penetration of water molecules, making it easier to form a hydrophobic system on the surface, thereby reducing the entry of water molecules into the plastic system. On the other hand, low-density linear polyethylene can increase the difficulty of water molecules moving in the system, while also improving the overall softness, thereby improving the moisture barrier on the basis of ensuring a lower modulus system, which not only protects the optical cable inside the material from being affected by external water, but also improves the protection of the polyurethane molecular chain from damage to the molecular chain due to the attack of water molecules on the amide group, thereby improving the weather resistance and barrier properties of the above materials in a high humidity environment.

[0017] On the above basis, due to the presence of low-density linear polyethylene and fluorinated polyolefin, the overall system is softer. Therefore, in the process of selecting polyurethane, it is preferred to use partially aromatic polyester polyols as the soft segment structure. First, compared with polyether polyols, some polyester polyols have better rigidity as a whole, and their barrier properties are stronger, and their mechanical properties such as tensile strength are also better. On the above basis, after adding some aromatic rings, their moisture resistance is stronger and they also have better rigidity. On the above basis, the silicone system is further used for end-capping, which eliminates the hydrophilic groups on the end groups on the one hand, and also improves the water barrier properties of the overall system.

[0018] On the basis of the above scheme, the polyester polyol is preferably a combination of an aromatic polyester polyol and an aliphatic polyester polyol, wherein the aromatic polyester polyol accounts for 25-30% of the mass of the polyester polyol. The soft aliphatic polyol can improve the overall softness in the system, and at this ratio, the rebound performance is the best while also maintaining the best water barrier performance. Among them, the aromatic polyester polyol is preferably a polymerization system of phthalic anhydride and any number of ethylene glycol, propylene glycol, and butanediol. Further preferably, the hydroxyl value of the aromatic polyester polyol is 400-460KOHmg·g -1 The selection of a relatively low molecular weight aromatic polyester polyol chain segment system can make the segments in the polyurethane have a relatively uniform distribution, which helps to achieve a uniform distribution overall, so as to achieve more uniform strength and moisture resistance in all regions of the material.

[0019] Preferably, the isocyanate is MDI, which may include 2,2'-MDI, 2,4'-MDI, 4,4'-MDI or other types of MDI, and the methylene groups between the benzene rings in MDI are used to form better flexibility, elasticity and wrapping properties, reduce internal crystallization and improve overall mechanical properties.

[0020] In addition, the organosilicon end-capping structure is preferably obtained by reacting a polysiloxane with a reactive group with a prepolymer of polyester polyol and isocyanate, wherein the reactive group is an amino group or a hydroxyl group. Further preferably, the polysiloxane with a reactive group is a single-end hydroxyl silicone oil, and the number average molecular weight of the single-end hydroxyl silicone oil is not greater than 1000. By modifying the system with medium and short molecular silanes, the silanes can form a more stable hydrophobic structure, and the short chains will not significantly increase the hydrophobicity of the polysiloxane.

[0021] Preferably, polyester can be added to the flame-retardant optical cable transmission equipment material, and the mass fraction of the polyester is 2 to 5 parts; the polyester is optionally polyethylene terephthalate, and the density of the polyester is 1.3 to 1.38 g / cm 3 .

[0022] Adding a certain amount of polyester can improve the mechanical properties of the system and the tensile strength to a certain extent. At the same time, it can also improve the overall elasticity of the system and make the mechanical strength better.

[0023] In addition, the present application also relates to a method for preparing the flame-retardant optical cable transmission equipment material. After the raw materials are mixed, they are kneaded and formed by a kneader at a temperature not higher than 180°C in a vacuum, and then the flame-retardant optical cable transmission equipment material is made by any one of encapsulation, injection molding, and extrusion.

[0024] In summary, the above scheme provides a flame-retardant material for optical cable transmission equipment, which, as a whole, ensures good mechanical properties while also providing high moisture resistance. After experiments, it was found that in a high humidity environment, the material can maintain good resilience, tensile properties and strength, and has good applicability prospects. DETAILED DESCRIPTION

[0025] The solution of the present application is further described through the following specific implementation methods.

[0026] In the present application, the polyurethane elastomer used can be obtained by copolymerization of polyester polyol and isocyanate, wherein in the present application, several different aromatic polyester polyols and aliphatic polyester polyols are mainly used, specifically, the aliphatic polyester polyol mainly uses poly(hexanediol adipate) (number average molecular weight 500-550), and the aromatic polyester polyol uses poly(ethylene phthalate) and poly(butylene phthalate), and different hydroxyl values ​​are obtained by controlling the molecular weight. In addition, after experiments, replacing poly(hexanediol adipate) with other aliphatic polyesters with similar molecular weight or degree of polymerization has little effect on the system performance.

[0027] In this scheme, the preparation method of polyurethane is as follows:

[0028] The polyester polyol is first mixed with a chain extender and a catalyst, and then the isocyanate is added to the system to react through a one-step reaction method to obtain a polyurethane elastomer. The reaction temperature is controlled to be 100°C. Based on 100 parts by mass of the polyester polyol, the catalyst is an organic tin catalyst, specifically dibutyltin dilaurate, and the mass portion is 0.01 to 0.1 parts. The functionality of the overall isocyanate group and the hydroxyl group of the system is controlled at about 1:1. The isocyanate can be slightly more, but the overall ratio should not exceed 1.05:1.01. After the reaction is completed, an excess of single-end hydroxyl silicone oil is added to the system, and the number average molecular weight ranges from 700 to 800. After sufficient reaction, the excess silicone oil or silane coupling agent can be removed by washing or centrifugation. On the whole, since the isocyanate group has a strong reactivity, the reaction can be completed by simple heating.

[0029] The hydroxyl value of polyester polyols and poly(hexamethylene adipate) is related to the degree of polymerization and can be controlled by controlling their overall molecular weight, which is also a parameter that characterizes the degree of polymerization.

[0030] By adjusting the ratio of different polyester polyols and the type of polyester polyol selected, different polyurethanes can be obtained, as shown in Table 1.

[0031] Table 1

[0032]

[0033]

[0034] The unit of hydroxyl value is KOHmg·g -1 , that is, the number of milligrams of KOH consumed per gram of product.

[0035] Furthermore, on the basis of Preparation Example 3, different silicon-terminated materials were used, as shown in Table 2.

[0036] Table 2

[0037] serial number Silane capping agent type 20 No end capping 21 Single-end hydroxy silicone oil, molecular weight 1400~1600 22 Single-end hydroxy silicone oil, molecular weight 200-300 23 Double-terminated hydroxyl silicone oil, molecular weight 700-800 24 3-Aminopropyltriethoxysilane 25 Single-ended amino silicone oil, molecular weight 700-800 26 Single-ended amino silicone oil, molecular weight 1300~1500

[0038] In the following examples, the above polyurethane and the following raw materials are first mixed in a high-speed mixer, then kneaded in a vacuum kneader, and then injection molded to obtain the target product. In actual use, the target product can also be prepared by encapsulation, extrusion or other methods. The specific raw material composition ratio is as follows:

[0039]

[0040] The phosphorus-containing flame retardant is polyphosphate, the glass fiber is commercially available low-boron glass fiber with an average diameter of 3.3 μm, the fluorinated polyolefin is polytetrafluoroethylene powder, the antioxidant is antioxidant 264, and the compatibilizer is maleic anhydride grafted polyethylene, all of which are commercially available.

[0041] For the following examples, the following detection methods were used to detect the products:

[0042] 1. Tensile strength: Refer to ISO 37:2017 Rubber, vulcanized or thermoplastic. Tensile stress to determine the tensile strength and elongation at break of the above materials.

[0043] 2. Hardness: Tested by Shore hardness standard at 25℃.

[0044] 3. Moisture and heat resistance test: Aging for 40 days in a 50°C, 100% humidity environment, then taking it out and letting it cool naturally to room temperature, and measuring the change in its tensile strength.

[0045] In addition, the following embodiments need to pass the flame retardancy test and have an afterflame time of less than 5 seconds before they are considered.

[0046] First, in this embodiment, the effects of using different polyurethanes in different preparation examples on the properties are shown in Table 3.

[0047] Table 3

[0048]

[0049]

[0050] Through the above experiments, it can be seen that, overall, with the increase in the amount of aromatic polyester polyols used, the overall hardness will increase, while the elongation at break and tensile strength have a trend of first increasing and then decreasing. Overall, when the aromatic polyester polyols account for 25-30% of the polyester polyol mass, the system has better moisture and heat resistance and mechanical properties. Overall, the hydroxyl value of the aromatic polyester polyol is 400-460KOHmg·g -1The higher the hydroxyl value, the lower the moisture and heat resistance. Since the polyester polyol has a smaller molecular weight, the mechanical properties of the system will also be reduced. The lower the hydroxyl value, the lower the strength of the system, the higher the hardness, and the lower the elongation at break.

[0051] In the selection of isocyanate, it can be seen that MDI as the isocyanate in the system has better softness and elongation at break than TDI, and better tensile strength than HDI.

[0052] The end-group silane termination system has a great influence on moisture resistance. Among them, the overall mechanical properties and moisture resistance of single-end hydroxyl silicone oil are the best, while the double-end hydroxyl silicone oil will increase the hardness of the system and reduce the elongation at break. In addition, amino silicone oil is slightly inferior to single-end hydroxyl polyurethane in moisture resistance, which may be caused by the amino group still having active hydrogen after the reaction. Silane coupling agent can also improve moisture and heat resistance in the system, but the effect is poorer than that of silicone oil system, and it has a small adverse effect on tensile strength. If the molecular weight of silicone oil is greater than 1000, it will increase the overall hardness of the system, which may be caused by the formation of a silane agglomeration system at the end of the molecular chain in the system.

[0053] Furthermore, based on the experimental group corresponding to number 4 in Table 3 (i.e., Preparation Example 4), a polyester system is further added to the system, and the experimental results shown in Table 3 can be obtained.

[0054] Table 4

[0055]

[0056] Among them, PET is polyethylene terephthalate, PBT is polybutylene terephthalate, and PEA is polyethylene adipate.

[0057] The above experiments show that after adding polyester, the overall hardness will be improved to a certain extent, and the tensile strength and moisture resistance will be significantly improved. The overall density of polyester is controlled at 1.3-1.38 g / cm 3 Too high a density will lead to a higher hardness of the system and a lower moisture resistance. This may be caused by the overly regular arrangement of the molecular weight, which leads to an uneven system in the system.

[0058] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A flame-retardant material for optical cable transmission equipment, characterized in that: The components are as follows according to mass parts: Polyurethane 100 parts 20-30 parts of fluorinated polyolefin 8-16 parts of low-density linear polyethylene Glass fiber 5-10 parts Antioxidant 0.1-1 part Compatibilizer 2-5 parts Phosphorus-containing flame retardant 5-10 parts The polyurethane is obtained by polymerization of polyester polyol and isocyanate, wherein the polyester polyol contains aromatic polyester polyol accounting for more than 20 to 40% of the mass of the polyester polyol; the polyurethane has an organosilicon end-capping structure; The fluorine-containing polyolefin is polytetrafluoroethylene or polyvinylidene fluoride.

2. A flame-retardant optical cable transmission equipment material according to claim 1, characterized in that: The polyester polyol is a combination of an aromatic polyester polyol and an aliphatic polyester polyol, wherein the aromatic polyester polyol accounts for 25-30% of the mass of the polyester polyol.

3. A flame-retardant optical cable transmission equipment material according to claim 2, characterized in that: The aromatic polyester polyol is a polymerization system of phthalic anhydride and any number of ethylene glycol, propylene glycol and butylene glycol.

4. A flame-retardant optical cable transmission equipment material according to claim 2, characterized in that: The aromatic polyester polyol has a hydroxyl value of 400 to 460 KOH mg·g -1 .

5. The flame-retardant optical cable transmission equipment material according to claim 1, characterized in that: The isocyanate is MDI.

6. The flame-retardant optical cable transmission equipment material according to claim 1, characterized in that: The organosilicon end-capped structure is obtained by reacting a polysiloxane with a reactive group with a prepolymer of a polyester polyol and an isocyanate, wherein the reactive group is an amino group or a hydroxyl group.

7. A flame-retardant optical cable transmission equipment material according to claim 6, characterized in that: The polysiloxane with reactive groups is a single-end hydroxy silicone oil, and the number average molecular weight of the single-end hydroxy silicone oil is not greater than 1000.

8. The flame-retardant optical cable transmission equipment material according to claim 1, characterized in that: The polyester is also included, and the mass proportion of the polyester is 2 to 5 parts; the polyester is optionally polyethylene terephthalate, and the density of the polyester is 1.3 to 1.38 g / cm 3 .

9. The flame-retardant optical cable transmission equipment material according to claim 1, characterized in that: The phosphorus-containing flame retardant is polyphosphate, and / or the compatibilizer is maleic anhydride grafted polyethylene.

10. The method for preparing the flame-retardant optical cable transmission equipment material according to any one of claims 1 to 9, characterized in that: After the above raw materials are mixed, they are kneaded and formed in a vacuum kneading machine at a temperature not higher than 180° C., and then the above flame-retardant optical cable transmission equipment material is made by any one of encapsulation, injection molding and extrusion.

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