An aramid fiber anti-photoaging sizing agent, anti-ultraviolet aramid fiber and preparation method

Abstract

The present invention relates to the technical field of aromatic polyamide fiber spinning aids, and specifically relates to a light aging resistant sizing agent for aramid fibers, an anti-ultraviolet aramid fiber and a preparation method thereof. The light aging resistant sizing agent includes a spinning sizing agent, an anti-ultraviolet aging agent and a coupling agent; the anti-ultraviolet aging agent includes inorganic nanoparticles and organic ultraviolet stabilizers. The preparation method of the anti-ultraviolet aramid fiber is as follows: perform an oiling operation on the para-aramid fiber, and then perform heating to achieve thermal crosslinking to obtain the anti-ultraviolet aramid fiber. By adding inorganic nanoparticles and organic ultraviolet stabilizers to the spinning sizing agent and fixing them on the fiber surface through a thermal crosslinking reaction, the present invention forms an anti-ultraviolet aging protection layer that can exert an ultraviolet protection effect, which can well solve the problems of poor anti-ultraviolet performance of para-aramid fibers and accelerated oxidation and degradation of polymer chains under ultraviolet light, and can also meet the requirements for fiber properties such as stretching and wear resistance in subsequent processes.

Description

Technical Field

[0001] The present invention relates to an anti - photo - aging sizing agent for aramid fibers, anti - ultraviolet aramid fibers and a preparation method thereof, belonging to the technical field of aromatic polyamide fiber spinning aids. Background Art

[0002] Para - aramid fibers have excellent properties such as high strength, high modulus, high temperature resistance, acid and alkali resistance, and light weight, and are widely used in the fields of national defense, military industry, aerospace, etc. However, para - aramid fibers themselves contain chromophore groups such as amide and benzene rings, so they are very sensitive to ultraviolet rays, easily absorb a large amount of ultraviolet rays and cause the breakage of molecular chains. Especially when exposed to ultraviolet light in the 280 - 320 nm band for a long time, it is extremely easy to undergo photo - aging degradation, resulting in embrittlement, cracking and yellowing, shortening the service life of aramid fabrics and affecting the further application of aramid materials.

[0003] At present, there are mainly two methods for preparing para - aramid fibers with anti - ultraviolet ability: on the one hand, adding organic or inorganic ultraviolet absorbers to the spinning dope and then spinning them into fibers. However, concentrated sulfuric acid must be used as the spinning solvent in the production process of para - aramid, and common ultraviolet absorbers will react with concentrated sulfuric acid, making the ultraviolet absorption ability unable to be exerted; on the other hand, directly coating a finishing agent or coating containing an ultraviolet absorber on the fiber surface. For example, the methods disclosed in the patent applications with publication numbers CN106592216A and CN112877858A are both coating sizing agents containing ultraviolet absorbers on the surface of aramid fibers to improve the anti - ultraviolet ability of the fibers. However, the disadvantage of this method is that with the use of the fibers and the change of the environment, the outer finishing agent or coating will be slowly worn off, making the anti - ultraviolet ability unable to be retained for a long time.

[0004] Therefore, in order to improve production efficiency, maintain the original fiber properties, improve the ultraviolet aging resistance of para - aramid fibers, and extend the service life of aramid products, it is necessary to explore a new process with simple process and stable effect. Summary of the Invention

[0005] Aiming at the deficiencies existing in the prior art, the present invention provides an anti - photo - aging sizing agent for aramid fibers, anti - ultraviolet aramid fibers and a preparation method thereof. After treating para - aramid fibers with the anti - photo - aging sizing agent, the fiber surface can have a good barrier absorption effect on ultraviolet rays, effectively slowing down the ultraviolet aging speed of para - aramid fibers and extending the service life.

[0006] The technical solution for the present invention to solve the above - mentioned technical problems is as follows: an anti - photo - aging sizing agent for aramid fibers, the anti - photo - aging sizing agent includes a spinning sizing agent, an anti - ultraviolet aging agent and a coupling agent; the anti - ultraviolet aging agent includes inorganic nanoparticles and organic ultraviolet stabilizers.

[0007] Furthermore, by weight parts, the anti-photoaging finishing agent comprises 85.0 - 90.0 parts of spinning finish, 9.0 - 14.0 parts of anti-ultraviolet aging agent, and 1.0 - 2.0 parts of coupling agent.

[0008] Furthermore, by weight parts, in the anti-ultraviolet aging agent, there are 3 - 8 parts of inorganic nanoparticles and 2 - 10 parts of organic high-ultraviolet stabilizer.

[0009] Furthermore, the weight ratio of the inorganic nanoparticles to the organic ultraviolet stabilizer is 1:(0.25 - 2.5).

[0010] Furthermore, the inorganic nanoparticles are nano-SiO₂ and nano-TiO₂, and the organic ultraviolet stabilizer is polysiloxane ultraviolet absorber and hindered amine light stabilizer.

[0011] Furthermore, the coupling agent is silane coupling agent.

[0012] The present invention also discloses a preparation method of the aramid fiber anti-photoaging finishing agent. The preparation method is as follows: add the anti-ultraviolet aging agent and the coupling agent to the spinning finish in sequence, after heating and raising the temperature, use a homogenizing head to homogenize and mix, and obtain the anti-photoaging finishing agent after filtration.

[0013] The present invention also discloses a preparation method of anti-ultraviolet aramid fiber. The preparation method is as follows: perform an oiling operation on para-aramid fiber, and then heat to achieve thermal crosslinking to obtain the anti-ultraviolet aramid fiber;

[0014] The oiling agent used in the oiling operation is the aramid fiber anti-photoaging finishing agent of the present invention.

[0015] Furthermore, the oiling operation adopts a roller oiling method, the oiling temperature is controlled at 55 - 65°C, and the oiling rate is 1.2 - 1.4%.

[0016] Furthermore, the heating temperature for achieving thermal crosslinking is 155 - 165°C.

[0017] The present invention also discloses an anti-ultraviolet aramid fiber, which is prepared by the preparation method of the present invention.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. The anti-photoaging finishing agent of the present invention can form a uniform protective layer on the surface of aramid fiber, effectively shield and absorb ultraviolet light. Moreover, for the aramid fiber obtained by the preparation method of the present invention, the anti-ultraviolet aging effect is significantly better than adding an ultraviolet absorber to the spinning dope, and problems such as the ultraviolet absorber being decomposed by strong acid and affecting the spinning forming during the spinning process are avoided.

[0020] 2. In the aspect of anti-ultraviolet aging agents, the present invention selects inorganic nanoparticles and organic ultraviolet stabilizers with different action forms and uses them in combination, and the effect is significantly better than that of using a single component; the nano-SiO₂ and nano-TiO₂ particles are different from common ultraviolet absorbers. They can not only absorb a part of ultraviolet light, but their greater function is to reflect or scatter most of the ultraviolet light to achieve a protective effect.

[0021] 3. In the preparation method of the anti-ultraviolet aramid fiber of the present invention, the polysiloxane ultraviolet absorber and the hindered amine light stabilizer will undergo a thermal cross-linking reaction after high-temperature treatment, and a uniform network structure will be formed on the surface of the aramid fiber. It can not only absorb and attenuate ultraviolet light, but also fix the nanoparticles on the fiber surface to achieve a multiple shielding-absorption effect on ultraviolet light, and can achieve long-term effect maintenance. Specific embodiments

[0022] The following will give a detailed description of the specific embodiments of the present invention. The present invention can be implemented in many other ways different from those described herein. Those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used are only for describing specific embodiments and do not limit the present invention.

[0024] An anti-photoaging sizing agent for aramid fiber, the anti-photoaging sizing agent includes a spinning sizing agent, an anti-ultraviolet aging agent, and a coupling agent; the anti-ultraviolet aging agent includes inorganic nanoparticles and an organic ultraviolet stabilizer.

[0025] Specifically, by weight, the anti-photoaging sizing agent includes 85.0 - 90.0 parts of a spinning sizing agent, 9.0 - 14.0 parts of an anti-ultraviolet aging agent, and 1.0 - 2.0 parts of a coupling agent.

[0026] Specifically, by weight, in the anti-ultraviolet aging agent, the inorganic nanoparticles are 3 - 8 parts, and the organic ultraviolet stabilizer is 2 - 10 parts.

[0027] Preferably, the weight ratio of the inorganic nanoparticles to the organic ultraviolet stabilizer is 1:(0.25 - 2.5).

[0028] Specifically, the inorganic nanoparticles are at least one of nano-SiO2 and nano-TiO2, preferably nano-SiO2; the organic ultraviolet stabilizer is at least one of polysiloxane ultraviolet absorber and hindered amine light stabilizer, preferably polysiloxane ultraviolet absorber. The inorganic nanoparticles have a strong reflection effect on ultraviolet rays, which can achieve the purpose of anti-ultraviolet aging; the organic ultraviolet stabilizer has a strong absorption effect on ultraviolet light, which can improve the ultraviolet stability of the fiber.

[0029] Specifically, the coupling agent is a silane coupling agent. The coupling agent can improve the surface activity of the para-aramid fiber surface and attach the inorganic nanoparticles to the aramid fiber surface.

[0030] More specifically, in the embodiments of the present invention, the spinning finish used is YTTH-10, the silane coupling agent is KH550, the nano-SiO2 particles are YC-S130X, the nano-TiO2 particles are R-706, the polysiloxane ultraviolet absorber is UV-531, and the hindered amine light stabilizer is LS-119.

[0031] A preparation method of an aramid fiber anti-photoaging finish, the preparation method is: sequentially add an anti-ultraviolet aging agent and a coupling agent to the spinning finish, heat up, and then use a homogenizing head to homogenize and mix, and filter to obtain the anti-photoaging finish.

[0032] Specifically, the heating temperature is 55-65 °C; the homogenizing speed is 3000-4000 r / min; the homogenizing time is 30-40 min.

[0033] The anti-photoaging finish is a light yellow oily liquid, and the compatibility between the components is good, and no delamination will occur after standing for 48 h.

[0034] A preparation method of anti-ultraviolet aramid fiber, the preparation method is: perform an oiling operation on the para-aramid fiber, and then heat it to achieve thermal crosslinking to obtain the anti-ultraviolet aramid fiber;

[0035] The finish used in the oiling operation is the aramid fiber anti-photoaging finish of the present invention.

[0036] Specifically, the oiling operation adopts a roller oiling method, the oiling temperature is controlled at 55-65 °C, the oiling rate is 1.2-1.4%, and the fiber winding speed is controlled at 150-160 m / min. During the oiling process, the anti-ultraviolet aging agent spreads on the fiber surface by means of the spinning finish, and can be evenly attached to the fiber surface layer, ensuring that the inorganic nanoparticles and the organic ultraviolet stabilizer are both evenly dispersed and tightly combined.

[0037] Specifically, the heating temperature during thermal crosslinking is 155 - 165 °C. The organic ultraviolet stabilizer forms a three-dimensional network structure during the subsequent thermal crosslinking process, which not only improves its binding ability with the fiber but also further fixes the inorganic nanoparticles on the fiber surface. The two cooperate with each other to jointly attenuate the damage of ultraviolet light to the fiber.

[0038] More specifically, the para-aramid fiber used in the examples of the present invention is 1500D para-aramid fiber.

[0039] An anti-ultraviolet aramid fiber, which is prepared according to the preparation method described in the present invention.

[0040] Example 1

[0041] An anti-aging oil agent for aramid fiber, by weight, comprises the following components: 85.0 parts of spinning oil agent, 14.0 parts of anti-ultraviolet aging agent (10.0 parts of polysiloxane ultraviolet absorber, 4.0 parts of nano-SiO2 particles), 1.0 part of silane coupling agent;

[0042] Add the anti-ultraviolet aging agent and the coupling agent to the spinning oil agent in sequence, control the temperature at 60 °C, stir at a speed of 3500 rpm for 30 min, make it fully homogenized and mixed evenly, and transfer it to a cooling kettle for filtration and cooling to obtain the anti-aging oil agent.

[0043] Preparation of an anti-ultraviolet aramid fiber:

[0044] The oil-free tow is drawn by a winder and passed through the oiling trough on the roller, the high-temperature heat pipe machine, and the five-roll tractor in sequence to complete the coating of the spinning oil agent and the anti-ultraviolet aging agent on the fiber surface;

[0045] Among them, the traction speed of the five-roll tractor is set at 150 m / min, the temperature of the oiling trough is set at 65 °C, and the heat crosslinking temperature of the heat pipe machine is set at 160 °C;

[0046] Based on the anti-ultraviolet aging aramid fiber obtained by the above process, two control experiments were designed to verify the anti-ultraviolet aging ability effect after 72 h of ultraviolet aging treatment and the anti-ultraviolet aging ability effect after 48 h of ultraviolet aging treatment after 5 washes respectively. After comparison, it was found that the mechanical property retention rates of the two were 98% and 97% respectively;

[0047] Example 2

[0048] An anti-aging oil agent for aramid fiber, by weight, comprises the following components: 90.0 parts of spinning oil agent, 9.0 parts of anti-ultraviolet aging agent (6.0 parts of polysiloxane ultraviolet absorber, 3.0 parts of nano-SiO2 particles), 1.0 part of silane coupling agent;

[0049] Add anti-ultraviolet aging agent and coupling agent to the spinning oil in sequence, control the reaction temperature to 60°C, stir at 3500rpm for 30min, mix them evenly after fully homogenizing, transfer them to a cooling kettle for filtration and cooling, and you can get the anti-light aging oil.

[0050] Preparation of a UV-resistant aramid fiber:

[0051] The oil-free tow is pulled through the winder and sequentially passes through the roller oil tank, high-temperature heat pipe machine, and five-roller traction machine to complete the coating of spinning oil and anti-ultraviolet aging agent on the fiber surface;

[0052] The traction speed of the five-roller traction machine is set to 150m / min, the upper oil tank temperature is set to 65℃, and the heat pipe machine is set to the heat cross-linking temperature of 160℃;

[0053] Based on the anti-ultraviolet aging aramid fiber obtained by the above process, two groups of control experiments were designed to verify the anti-ultraviolet aging effect after 72h ultraviolet aging treatment and the anti-ultraviolet aging effect after 48h ultraviolet aging treatment after 5 washes. The comparison found that the mechanical property retention rates of the two were 95% and 94% respectively;

[0054] Example 3

[0055] An aramid fiber anti-light aging oil, comprising the following components by weight: 89.0 parts of spinning oil, 10.0 parts of anti-ultraviolet aging agent (6.0 parts of polysiloxane ultraviolet absorber, 4.0 parts of nano-SiO2 particles), and 1.0 parts of silane coupling agent;

[0056] Add anti-ultraviolet aging agent and coupling agent to the spinning oil in sequence, control the reaction temperature to 60°C, stir at 3500rpm for 30min, mix them evenly after fully homogenizing, transfer them to a cooling kettle for filtration and cooling, and you can get the anti-light aging oil.

[0057] Preparation of a UV-resistant aramid fiber:

[0058] The oil-free tow is pulled through the winder and sequentially passes through the roller oil tank, high-temperature heat pipe machine, and five-roller traction machine to complete the coating of spinning oil and anti-ultraviolet aging agent on the fiber surface;

[0059] The traction speed of the five-roller traction machine is set to 150m / min, the upper oil tank temperature is set to 65℃, and the heat pipe machine is set to the heat cross-linking temperature of 160℃;

[0060] Based on the anti-ultraviolet aging aramid fiber obtained by the above process, two groups of control experiments were designed and completed to verify the anti-ultraviolet aging ability effect after 72h ultraviolet aging treatment and the anti-ultraviolet aging ability effect after 48h ultraviolet aging treatment after 5 washes. After comparison, it was found that the mechanical property retention rates of the two were 97% and 95% respectively;

[0061] Example 4

[0062] An anti-photoaging sizing agent for aramid fiber, by weight, comprises the following components: 86.0 parts of spinning sizing agent, 12.0 parts of anti-ultraviolet aging agent (6.0 parts of polysiloxane ultraviolet absorber, 6.0 parts of nano-SiO2 particles), and 2.0 parts of silane coupling agent;

[0063] Add the anti-ultraviolet aging agent and the coupling agent to the spinning sizing agent in sequence, control the reaction temperature at 55 °C, stir at a speed of 4000 rpm for 40 min, make it mix evenly after sufficient homogenization, transfer it to a cooling kettle for filtration and cooling, and then the anti-photoaging sizing agent can be obtained.

[0064] Preparation of an anti-ultraviolet aramid fiber:

[0065] The oil-free tow is drawn by a winder and passed through the roller oil bath, high-temperature heat pipe machine, and five-roll drawing machine in sequence to complete the coating of the spinning sizing agent and the anti-ultraviolet aging agent on the fiber surface;

[0066] Among them, the drawing speed of the five-roll drawing machine is set at 150 m / min, the temperature of the oil bath is set at 60 °C, and the heat cross-linking temperature of the heat pipe machine is set at 165 °C;

[0067] Based on the anti-ultraviolet aging aramid fiber obtained by the above process, two groups of control experiments were designed and completed to verify the anti-ultraviolet aging ability effect after 72h ultraviolet aging treatment and the anti-ultraviolet aging ability effect after 48h ultraviolet aging treatment after 5 washes. After comparison, it was found that the mechanical property retention rates of the two were 95% and 94% respectively;

[0068] Example 5

[0069] An anti-photoaging sizing agent for aramid fiber, by weight, comprises the following components: 88.0 parts of spinning sizing agent, 10.0 parts of anti-ultraviolet aging agent (4.0 parts of polysiloxane ultraviolet absorber, 6.0 parts of nano-SiO2 particles), and 2.0 parts of silane coupling agent;

[0070] Add the anti-ultraviolet aging agent and the coupling agent to the spinning sizing agent in sequence, control the reaction temperature at 65 °C, stir at a speed of 3500 rpm for 30 min, make it mix evenly after sufficient homogenization, transfer it to a cooling kettle for filtration and cooling, and then the anti-photoaging sizing agent can be obtained.

[0071] Preparation of a UV-resistant aramid fiber:

[0072] The oil-free tow is pulled through the winder and sequentially passes through the roller oil tank, high-temperature heat pipe machine, and five-roller traction machine to complete the coating of spinning oil and anti-ultraviolet aging agent on the fiber surface;

[0073] The traction speed of the five-roller traction machine is set to 150m / min, the upper oil tank temperature is set to 65℃, and the heat pipe machine is set to the thermal cross-linking temperature of 165℃;

[0074] Based on the anti-ultraviolet aging aramid fiber obtained by the above process, two groups of control experiments were designed to verify the anti-ultraviolet aging effect after 72h of ultraviolet aging treatment and the anti-ultraviolet aging effect after 48h of ultraviolet aging treatment after 5 washes. The mechanical property retention rates of the two were 98% and 97% respectively.

[0075] Example 6

[0076] An aramid fiber anti-light aging oil, comprising the following components by weight: 89.0 parts of spinning oil, 9.0 parts of anti-ultraviolet aging agent (3.0 parts of polysiloxane ultraviolet absorber, 6.0 parts of nano-SiO2 particles), and 2.0 parts of silane coupling agent;

[0077] Add anti-ultraviolet aging agent and coupling agent to the spinning oil in sequence, control the reaction temperature to 60°C, stir at 3500rpm for 30 min, fully homogenize and mix evenly, transfer to a cooling kettle for filtration and cooling, and you can get the anti-light aging oil.

[0078] Preparation of a UV-resistant aramid fiber:

[0079] The oil-free tow is pulled through the winder and sequentially passes through the roller oil tank, high-temperature heat pipe machine, and five-roller traction machine to complete the coating of spinning oil and anti-ultraviolet aging agent on the fiber surface;

[0080] The traction speed of the five-roller traction machine is set to 150m / min, the upper oil tank temperature is set to 65℃, and the heat pipe machine is set to the thermal cross-linking temperature of 155℃;

[0081] Based on the anti-ultraviolet aging aramid fiber obtained by the above process, two groups of control experiments were designed to verify the anti-ultraviolet aging effect after 72h of ultraviolet aging treatment and the anti-ultraviolet aging effect after 48h of ultraviolet aging treatment after 5 washes. The mechanical property retention rates of the two were 97% and 95% respectively.

[0082] Example 7

[0083] An aramid fiber anti-light aging oil, comprising the following components by weight: 88.0 parts of spinning oil, 10.0 parts of anti-ultraviolet aging agent (2.0 parts of polysiloxane ultraviolet absorber, 8.0 parts of nano-SiO2 particles), and 2.0 parts of silane coupling agent;

[0084] Add anti-ultraviolet aging agent and coupling agent to the spinning oil in sequence, control the reaction temperature to 60°C, stir at 3500rpm for 30min, mix them evenly after fully homogenizing, transfer them to a cooling kettle for filtration and cooling, and you can get the anti-light aging oil.

[0085] Preparation of a UV-resistant aramid fiber:

[0086] The oil-free tow is pulled through the winder and sequentially passes through the roller oil tank, high-temperature heat pipe machine, and five-roller traction machine to complete the coating of spinning oil and anti-ultraviolet aging agent on the fiber surface;

[0087] The traction speed of the five-roller traction machine was set to 150 m / min, the upper oil tank temperature was set to 65°C, and the heat pipe machine was set to a heat cross-linking temperature of 160°C;

[0088] Based on the UV-resistant aramid fiber obtained by the above process, two groups of control experiments were designed to verify the anti-UV aging effect after 72 hours of UV aging treatment and the anti-UV aging effect after 48 hours of UV aging treatment after 5 washes. By comparison, it was found that the mechanical property retention rates of the two were 98% and 96%, respectively.

[0089] Example 8

[0090] An aramid fiber anti-light aging oil, comprising the following components by weight: 85.0 parts of spinning oil, 14.0 parts of anti-ultraviolet aging agent (10.0 parts of polysiloxane ultraviolet absorber, 4.0 parts of nano-TiO2 particles), and 1.0 parts of silane coupling agent;

[0091] Add anti-ultraviolet aging agent and coupling agent to the spinning oil in sequence, control the temperature to 60°C, stir at 3500rpm for 30min, fully homogenize and mix evenly, transfer to a cooling kettle for filtration and cooling, and you can get the anti-light aging oil.

[0092] Preparation of a UV-resistant aramid fiber:

[0093] The oil-free tow is pulled through the winder and sequentially passes through the roller oil tank, high-temperature heat pipe machine, and five-roller traction machine to complete the coating of spinning oil and anti-ultraviolet aging agent on the fiber surface;

[0094] The traction speed of the five-roller traction machine was set to 150 m / min, the upper oil tank temperature was set to 65°C, and the heat pipe machine was set to a heat cross-linking temperature of 160°C;

[0095] Based on the anti-ultraviolet aging aramid fiber obtained by the above process, two groups of control experiments were designed to verify the anti-ultraviolet aging effect after 72h of ultraviolet aging treatment and the anti-ultraviolet aging effect after 48h of ultraviolet aging treatment after 5 washes. The mechanical property retention rates of the two were 96% and 98% respectively.

[0096] Example 9

[0097] An aramid fiber anti-light aging oil, comprising the following components by weight: 85.0 parts of spinning oil, 14.0 parts of anti-ultraviolet aging agent (10.0 parts of hindered amine light stabilizer, 4.0 parts of nano-SiO2 particles), and 1.0 parts of silane coupling agent;

[0098] Add anti-ultraviolet aging agent and coupling agent to the spinning oil in sequence, control the temperature to 60°C, stir at 3500rpm for 30min, fully homogenize and mix evenly, transfer to a cooling kettle for filtration and cooling, and you can get the anti-light aging oil.

[0099] Preparation of a UV-resistant aramid fiber:

[0100] The oil-free tow is pulled through the winder and sequentially passes through the roller oil tank, high-temperature heat pipe machine, and five-roller traction machine to complete the coating of spinning oil and anti-ultraviolet aging agent on the fiber surface;

[0101] The traction speed of the five-roller traction machine was set to 150 m / min, the upper oil tank temperature was set to 65°C, and the heat pipe machine was set to a heat cross-linking temperature of 160°C;

[0102] Based on the anti-ultraviolet aging aramid fiber obtained by the above process, two groups of control experiments were designed to verify the anti-ultraviolet aging effect after 72h of ultraviolet aging treatment and the anti-ultraviolet aging effect after 48h of ultraviolet aging treatment after 5 washes. The mechanical property retention rates of the two were 98% and 96% respectively.

[0103] Comparative Example 1

[0104] This comparative example 1 is substantially the same as the example 1, except that, in the preparation process of the anti-ultraviolet aramid fiber, the thermal crosslinking reaction process at 160° C. is not performed;

[0105] Based on the anti-ultraviolet aging aramid fibers obtained by the above process, two groups of control experiments were designed and completed to verify the anti-ultraviolet aging ability after 72h ultraviolet aging treatment and the anti-ultraviolet aging ability after 48h ultraviolet aging treatment after 5 washings, respectively. Through comparison, it was found that the mechanical property retention rates of the two were 87% and 76% respectively.

[0106] Comparative Example 2

[0107] This Comparative Example 2 is basically the same as Example 1, except that during the preparation of the anti-photoaging sizing agent, no anti-ultraviolet aging agent and coupling agent are added;

[0108] Based on the anti-ultraviolet aging aramid fibers obtained by the above process, two groups of control experiments were designed and completed to verify the anti-ultraviolet aging ability after 72h ultraviolet aging treatment and the anti-ultraviolet aging ability after 48h ultraviolet aging treatment after 5 washings, respectively. Through comparison, it was found that the mechanical property retention rates of the two were 72% and 70% respectively.

[0109] Comparative Example 3

[0110] This Comparative Example 3 is basically the same as Example 1, except that during the preparation of the anti-photoaging sizing agent, no coupling agent is added;

[0111] Based on the anti-ultraviolet aging aramid fibers obtained by the above process, two groups of control experiments were designed and completed to verify the anti-ultraviolet aging ability after 72h ultraviolet aging treatment and the anti-ultraviolet aging ability after 48h ultraviolet aging treatment after 5 washings, respectively. Through comparison, it was found that the mechanical property retention rates of the two were 93% and 84% respectively.

[0112] Comparative Example 4

[0113] This Comparative Example 4 is basically the same as Example 1, except that during the preparation of the anti-photoaging sizing agent, no anti-ultraviolet aging agent is added;

[0114] Based on the anti-ultraviolet aging aramid fibers obtained by the above process, two groups of control experiments were designed and completed to verify the anti-ultraviolet aging ability after 72h ultraviolet aging treatment and the anti-ultraviolet aging ability after 48h ultraviolet aging treatment after 5 washings, respectively. Through comparison, it was found that the mechanical property retention rates of the two were 72% and 71% respectively.

[0115] Comparative Example 5

[0116] This Comparative Example 5 is basically the same as Example 1, except that during the preparation of the anti-photoaging sizing agent, all the anti-ultraviolet aging agents used are polysiloxane ultraviolet absorbers and do not contain nano-SiO2 particles.

[0117] Based on the anti-ultraviolet aging aramid fiber obtained by the above process, two groups of control experiments were designed and completed to verify the anti-ultraviolet aging ability effect after 72 h of ultraviolet aging treatment and the anti-ultraviolet aging ability effect after 48 h of ultraviolet aging treatment after 5 washings. After comparison, it was found that the mechanical property retention rates of the two were 80% and 79% respectively.

[0118] Comparative Example 6

[0119] This Comparative Example 6 is basically the same as Example 1, except that in the preparation process of the anti-photoaging sizing agent, all the anti-ultraviolet aging agents used are nano-SiO2 particles and do not contain polysiloxane ultraviolet absorbers.

[0120] Based on the anti-ultraviolet aging aramid fiber obtained by the above process, two groups of control experiments were designed and completed to verify the anti-ultraviolet aging ability effect after 72 h of ultraviolet aging treatment and the anti-ultraviolet aging ability effect after 48 h of ultraviolet aging treatment after 5 washings. After comparison, it was found that the mechanical property retention rates of the two were 78% and 78% respectively.

[0121] Comparative Example 7

[0122] This Comparative Example 6 is basically the same as Example 1, except that in the preparation process of the anti-photoaging sizing agent, the anti-ultraviolet aging agent used includes 2.0 parts of polysiloxane ultraviolet absorber and 12.0 parts of nano-SiO2 particles (the weight ratio of the inorganic nanoparticles and the organic polymer ultraviolet absorber is not within the range of 1:(0.25 - 2.5)).

[0123] Based on the anti-ultraviolet aging aramid fiber obtained by the above process, two groups of control experiments were designed and completed to verify the anti-ultraviolet aging ability effect after 72 h of ultraviolet aging treatment and the anti-ultraviolet aging ability effect after 48 h of ultraviolet aging treatment after 5 washings. After comparison, it was found that the mechanical property retention rates of the two were 82% and 85% respectively.

[0124] The anti-ultraviolet aging aramid fibers prepared in the above examples and comparative examples were subjected to performance tests. The specific results are shown in Table 1 below. After the products in each example and comparative example were washed 5 times and then irradiated with ultraviolet light for 48 h, the decrease in mechanical indexes was tested, and the results are shown in Table 2.

[0125] The performance test methods involved are: ASTM G154-2023 "Standard Practice for Operating Fluorescent UV Lamps for Exposure of Nonmetallic Materials" and GB / T14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments".

[0126] Table 1 Test results of anti-ultraviolet properties of anti-ultraviolet aging aramid fibers prepared in examples and comparative examples

[0127]

[0128] Table 2 Test results of anti-ultraviolet performance of anti-ultraviolet aging aramid fibers prepared in examples and comparative examples after washing

[0129]

[0130] As can be seen from Table 1, after 72 h of ultraviolet irradiation aging test, the anti-ultraviolet aging aramid fibers prepared in Examples 1-9 all maintained a high breaking strength retention rate and modulus retention rate. As can be seen from Table 2, after 5 washes and 48 h of ultraviolet light irradiation, the decrease in the breaking strength and modulus of the anti-ultraviolet aging aramid fibers prepared in Examples 1-9 was small. It can be thus explained that the anti-ultraviolet aging effect of the anti-photoaging sizing agent of the present invention on the fibers can still maintain a good effect after multiple water washes, and the service life of aramid products in practical applications will be significantly extended.

[0131] From the data comparison between Comparative Example 1 and Example 1, it can be seen that when preparing anti-ultraviolet aging aramid fibers, if no thermal cross-linking treatment is carried out, the breaking strength retention rate and modulus retention rate of the fibers will decrease significantly after ultraviolet irradiation; there are also obvious differences in the breaking strength and modulus before and after washing. The anti-ultraviolet aging degree of the sizing agent after the thermal cross-linking reaction is more excellent, and the anti-ultraviolet aging agent can be better fixed on the fiber surface after high-temperature treatment.

[0132] From the data comparison between Comparative Example 2 and Example 1, it can be seen that adding an anti-ultraviolet aging agent can significantly improve the ultraviolet aging effect of the fibers. Compared with normal products, the breaking strength and modulus of the fibers irradiated by ultraviolet light can be increased by more than 20%.

[0133] From the data comparison between Comparative Example 3 and Example 1, it can be seen that if a coupling agent is not added, the anti-ultraviolet aging performance of the fibers will decrease. Adding a coupling agent can make the nano-SiO2 particles better combine with the fibers, and the addition of the coupling agent has a promoting effect on improving the anti-ultraviolet aging effect of the fibers.

[0134] From the data comparison between Comparative Example 4 and Example 1, it can be seen that only adding a coupling agent without adding an anti-ultraviolet aging agent component does not improve the anti-ultraviolet aging effect of the fibers, and even the breaking strength will decrease.

[0135] From the data comparison between Comparative Example 5 and Example 1, it can be seen that if the anti-ultraviolet aging agent only contains a polysiloxane ultraviolet absorber and does not contain nano-SiO2 particles, the anti-ultraviolet aging performance of the fibers will decrease.

[0136] From the data comparison between Comparative Example 6 and Example 1, it can be seen that: if the anti-ultraviolet aging agent only contains nano-SiO2 particles and does not contain polysiloxane ultraviolet absorber, the anti-ultraviolet aging performance of the fiber will decline. From the comparison among Comparative Example 5, Comparative Example 6 and Example 1, it can be seen that the co-application of polysiloxane ultraviolet absorber and nano-SiO2 particles in the spinning finish is more conducive to improving the anti-ultraviolet aging performance of para-aramid fiber. Nano-SiO2 particles have a strong reflection effect on ultraviolet rays, which can achieve the purpose of anti-ultraviolet aging; polysiloxane ultraviolet absorber has a strong absorption effect on ultraviolet light, which can improve the ultraviolet stability of the fiber; in the preparation method of anti-ultraviolet aramid fiber, the polysiloxane ultraviolet absorber will undergo a thermal cross-linking reaction after high-temperature treatment and spread on the surface of the aramid fiber to form a uniform network structure. It can not only absorb and attenuate ultraviolet light, but also fix nano-SiO2 particles on the fiber surface, achieving a multiple shielding-absorption effect on ultraviolet light and realizing long-term effect retention.

[0137] From the data comparison between Comparative Example 7 and Example 1, it can be seen that a suitable ratio between the polysiloxane ultraviolet absorber and nano-SiO2 particles is more conducive to obtaining a para-aramid fiber product with excellent anti-ultraviolet performance.

[0138] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, all possible combinations of the technical features in the above embodiments are not exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0139] For those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. The protection scope of the present invention shall be subject to the appended claims.

Claims

1. An aramid fiber anti-photoaging sizing agent, characterized in that, The anti-photoaging sizing agent comprises a spinning sizing agent, an anti-ultraviolet aging agent and a coupling agent; the anti-ultraviolet aging agent comprises inorganic nanoparticles and an organic ultraviolet stabilizer; the weight ratio of the inorganic nanoparticles to the organic ultraviolet stabilizer is 1:(0.25 - 2.5); The organic ultraviolet stabilizer is at least one of a polysiloxane ultraviolet absorber and a hindered amine light stabilizer; the coupling agent is a silane coupling agent; After sizing para-aramid fibers with the anti-photoaging sizing agent, a thermal cross-linking treatment is carried out at 155 - 165 °C.

2. The aramid fiber anti-photoaging finishing agent according to claim 1, characterized in that By weight, the anti-photoaging sizing agent comprises 85.0 - 90.0 parts of a spinning sizing agent, 9.0 - 14.0 parts of an anti-ultraviolet aging agent, and 1.0 - 2.0 parts of a coupling agent.

3. The aramid fiber anti-photoaging finishing agent according to claim 2, wherein By weight, in the anti-ultraviolet aging agent, there are 3 - 8 parts of the inorganic nanoparticles and 2 - 10 parts of the organic ultraviolet stabilizer.

4. The aramid fiber anti-photoaging finishing agent according to any one of claims 1-3, characterized in that, The inorganic nanoparticles are at least one of nano-SiO2 and nano-TiO2.

5. A preparation method of an aramid fiber anti-photoaging finishing agent according to any one of claims 1-4, characterized in that, The preparation method is as follows: the anti-ultraviolet aging agent and the coupling agent are sequentially added to the spinning sizing agent, after heating and raising the temperature, homogenization and mixing are carried out using a homogenizing head, and the anti-photoaging sizing agent is obtained after filtration.

6. A preparation method of anti-ultraviolet aramid fiber, characterized in that, The preparation method is as follows: para-aramid fibers are sized, and then heating is carried out to achieve thermal cross-linking to obtain the anti-ultraviolet aramid fibers; The sizing agent used in the sizing operation is the aramid fiber anti-photoaging sizing agent according to any one of claims 1 - 4.

7. The preparation method of an anti-ultraviolet aramid fiber according to claim 6, characterized in that, The sizing operation adopts a roller sizing method, the sizing temperature is controlled at 55 - 65 °C, and the sizing rate is 1.2 - 1.4%.

8. An anti-ultraviolet aramid fiber, characterized in that, The anti-ultraviolet aramid fibers are prepared by the preparation method according to any one of claims 6 - 7.

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