CN102691207A - A kind of preparation method of PBO fiber with both ultraviolet light resistance and humidity and heat aging resistance - Google Patents

Abstract

The invention relates to a preparation method of PBO fiber with ultraviolet light resistance and damp-heat aging resistance, which comprises the following specific steps: (1) preparing organic silicon hydrophobic sol; (2) preparing organic silicon hydrophobic sol composite finishing liquid; (3) and (3) soaking the PBO fiber into the organic silicon hydrophobic sol composite finishing liquid obtained in the step (2) for 0.5-2 hours, then taking out the fiber, naturally airing the fiber for 12-48 hours at room temperature, and curing the fiber for 2-5 hours in a drying oven at the temperature of 80-100 ℃ to obtain the PBO fiber with the uniform hydrophobic coating on the surface. The invention has the advantages that: ethanol is used as a dispersing agent, so that the light stabilizer is uniformly dispersed in the organic silicon coating precursor, the uniformity of dispersion is ensured, and the ultraviolet light aging resistance is endowed; and in the curing process, the ethanol is volatilized, and the organic siloxane is crosslinked and cured on the surface of the fiber to form a hydrophobic organic silicon coating so as to endow the fiber with the damp-heat aging resistance.

Description

A kind of preparation method of PBO fiber with both ultraviolet light resistance and humidity and heat aging resistance

【Technical field】

The invention relates to the technical field of PBO fibers, in particular to a preparation method of PBO fibers which are resistant to ultraviolet light and moisture and heat aging.

【Background technique】

Polyphenylenebenzobisoxazole (referred to as PBO) is a rigid rod-shaped liquid crystal polymer with a full aromatic heterocycle. The PBO fiber produced by the dry-jet wet spinning process has many excellent properties such as high strength, high modulus, and high temperature resistance. Known as "the super fiber of the 21st century", it is one of the high-performance fibers with the best comprehensive properties at present, and has very broad application prospects in high-tech fields such as aerospace, national defense and military.

Although PBO fiber has excellent performance, the aging and failure of its products during use has plagued the use of PBO fiber, especially the body armor made of PBO fiber has obvious aging phenomenon in less than 5 years, and This resulted in serious casualties. Since the aging of PBO fiber under ultraviolet light and humidity conditions is much faster than originally expected, this greatly limits the development and application of PBO fiber in high-tech fields. Therefore, it is necessary to study the anti-aging technology of PBO fiber and prepare PBO fiber with good aging resistance.

The aging of PBO fibers can be divided into three categories: thermal oxygen aging, damp heat aging and ultraviolet aging. In the normal use environment, the impact of damp heat aging and ultraviolet light aging on the performance of PBO fiber is more common and serious. It is generally believed that the hygrothermal aging of PBO fibers is due to the penetration of water molecules into the interior of PBO fibers through capillary effects, etc., and after a series of physical and chemical processes, the mechanical properties of the fibers are reduced; In the case of irradiation, the molecular chain structure is destroyed, resulting in a decrease in the mechanical properties of the fiber.

At present, there are many researches on the UV aging resistance of PBO fibers at home and abroad. For the technology of moisture and heat aging resistance, there are few patents and literatures reported, and there is no report on the method of simultaneously achieving UV aging and moisture aging.

There have been many patents and documents on the UV aging resistance technology of PBO fiber. Generally speaking, its technology is divided into two categories. The first category is to add anti-aging agent into the polymerization system for in-situ polymerization and spinning. Specifically, such as Chinese patent CN101397696A, it directly adds anti-ultraviolet agent TM in the reaction system, after the reaction is completed, the material is extruded with a twin-screw or single-screw extruder, and is spun into PBO fibers by a dry-jet wet spinning process. Thereby improving the UV resistance of PBO fiber. Another example is the Chinese patent CN101215732A, which adds a mixture of polyphosphoric acid and nano-TiO ₂ into the PBO reaction system, and obtains UV-resistant PBO fibers through in-situ polymerization. This type of method often affects the polymerization process of PBO due to the direct addition of additives in the reaction system, resulting in a decrease in the strength and molecular weight of PBO fibers; on the other hand, due to the high concentration of the spinning solution of PBO fibers, the additives are very It is difficult to disperse evenly in the spinning solution, and inorganic nanoparticles such as TiO ₂ are easy to agglomerate, and the dispersion effect is even worse.

The second type of method is to process the fibers after they are spun and formed. The biggest feature of this type of method is that the fiber is processed after the PBO fiber is spun and formed, which can achieve the predetermined effect without interfering with the spinning process of the PBO fiber and affecting the fiber performance. This type of method is mostly reported to use the sol-gel method to prepare TiO ₂ coating, and use the anti-ultraviolet effect of TiO ₂ to improve the light aging resistance of the fiber. Specifically, Liu Xiaoyan et al. prepared TiO ₂ hydrosol by hydrolysis of tetrabutyl titanate, and baked and dried at 150°C to form a TiO ₂ coating on the fiber. The light resistance of the fiber after coating was improved to a certain extent. (Liu Xiaoyan. Improving the photo-stability of high performance aramid fibers by sol-gel treatment. Fibers and Polymers, 2008, 9(4): 455-460). Qiu Jun et al. used a specific ratio of TiO ₂ sol to form a TiO ₂ coating on the surface of PBO fibers, which improved the UV resistance of PBO fibers. (Qiu Jun. Preparation of nano-TiO2 sol and its effect on the anti-ultraviolet aging of PBO fiber. Journal of Yancheng Institute of Technology (Natural Science Edition), 2009, 22(1): 35～39)

However, the above methods use TiO ₂ hydrosol directly as an anti-aging coating, the treatment temperature is high, and there are problems that nano-TiO ₂ particles are easy to agglomerate on the fiber surface, difficult to disperse, and cannot effectively cover the fiber surface. For this reason, some researchers have used the method of dispersant, which can greatly improve the uniformity of dispersion. For example, in patent CN102277726A, TiO ₂ -ZnO composite water sol finishing solution is first prepared, and polyethylene glycol is used as a dispersant to immerse PBO fibers in the finishing solution for super-production oscillation. After drying, an anti-ultraviolet coating is formed on the surface of PBO fibers, thereby achieving Anti-ultraviolet aging effect. However, in order to uniformly disperse the nanoparticles in the sol, the dispersant polyethylene glycol used in this patent is hydrophilic, which causes the surface of the fiber to become hydrophilic. While improving the light aging resistance of the PBO fiber, On the contrary, it will aggravate the humidity and heat aging of PBO fiber.

【Content of invention】

The purpose of the present invention is to overcome the deficiencies of the prior art, provide a PBO fiber preparation method with both UV resistance and damp heat aging resistance, and take into account the UV aging resistance and damp heat aging resistance of the PBO fiber.

The purpose of the present invention is achieved through the following technical solutions:

A method for preparing a PBO fiber with both UV resistance and humidity and heat aging resistance, the specific steps are:

(1) Heat and mix silica sol precursor, ethanol (EtOH) and hydrochloric acid (HCl) at 25-30°C respectively, add hydrophobic siloxane after mixing evenly, and continue to react at 25-30°C for 3~ 5h, to obtain a uniform and stable silicone hydrophobic sol;

The silica sol precursor is one of ethyl orthosilicate and methyl orthosilicate;

The hydrophobic siloxane is a siloxane with a hydrophobic group, such as trimethoxyphenylsilane, triethoxyphenylsilane, perfluorotriethoxysilane, methyltriethoxysilane , one of methyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, vinyltriethoxysilane, octyltriethoxysilane;

The volume ratio of the silica sol precursor, ethanol, hydrochloric acid, and hydrophobic siloxane is 1:5-10:0.05-1:1.5-5.0;

(2) Warm up the organic silicon hydrophobic sol obtained in step (1) to 40-80°C, add an ultraviolet light absorber, and mix the ultraviolet light absorber and organic silicon hydrophobic sol evenly with the assistance of ultrasonic oscillation, and the oscillation time is 0.5 ~2h, then cooled to room temperature, and added a curing catalyst to obtain a uniform and stable organosilicon hydrophobic sol composite finishing solution;

Described ultraviolet absorber is the ultraviolet absorber soluble in ethanol, for example one of UV-9, UV-328, UV-531, UV-O, phenyl salicylate, ultraviolet absorber RMB or several mixtures;

The mass fraction of the ultraviolet absorber is 0.1% to 2% relative to the total mass of the organic silicon hydrophobic sol;

The curing catalyst is a conventional organosilicon crosslinking curing catalyst, such as acetylcholine, aluminum acetylacetonate, dibutyltin dilaurate, diethylenetriamine, triethylenetetramine, triethanolamine, silicon nitrogen oligomers, p-toluenesulfonate Acid, dimethylbenzylamine, cobalt naphthenate, etc., a large number of reports about the formula and optimal addition amount of this type of catalyst have been disclosed in the literature.

(3) Immerse the PBO fiber into the organosilicon hydrophobic sol composite finishing solution obtained in step (2) for 0.5-2 hours, then take out the fiber, dry it naturally at room temperature for 12-48 hours, and place it in a drying box for 80-2 hours. Curing at 100°C for 2 to 5 hours to obtain PBO fibers with a uniform hydrophobic coating on the surface.

Compared with prior art, positive effect of the present invention is:

(1) The core idea of the present invention is to use ethanol as a dispersant to uniformly disperse the light stabilizer in the organosilicon coating precursor, thereby ensuring the uniformity of dispersion and endowing it with UV aging resistance; During the joint curing process, the ethanol volatilizes, and the organosiloxane cross-links on the surface of the fiber to form a hydrophobic silicone coating, which endows the fiber with the ability to resist moisture and heat aging.

(2) The present invention carries out anti-aging treatment on the surface of the finished PBO fiber, which will not interfere with the polymerization and spinning process of PBO, and will not affect the original excellent performance of the PBO fiber.

(3) The present invention adopts organic silicon coating, adds the method for ultraviolet absorber in sol, because the characteristic of coating itself is hydrophobic, water molecule is difficult to absorb and penetrate into fiber interior, makes this method can improve the ultraviolet resistance of fiber at the same time Light aging and humidity and heat aging resistance.

(4) The preparation steps of the sol system of the present invention are simple, do not need to be processed at high temperature, and the ultraviolet light absorber is uniformly dispersed in the silica sol, there is no agglomeration problem, and the distribution of the ultraviolet light absorber on the fiber surface is uniform after the coating is cured sex is better.

【Detailed ways】

The following provides a specific embodiment of a method for preparing a PBO fiber of the present invention that is resistant to ultraviolet light and moisture and heat aging.

Comparative example 1

Without any treatment, the PBO fiber has a fiber strength retention rate of 52% after being irradiated by 1100w/m ² ultraviolet light for 110 hours. Under the conditions of 80°C, 80% relative humidity and no ultraviolet light irradiation, only the moisture and heat aging resistance of the fiber was investigated, and the fiber strength retention rate was 79% after 360 hours.

Comparative example 2

(1) Weigh 5mL tetraethyl orthosilicate, 25mL ethanol (EtOH) and 4mL hydrochloric acid (HCl) respectively, heat and mix them evenly at 25°C, add 7.5mL trimethoxyphenylsilane, and continue to stir at 25°C for 5h , adding the curing catalyst aluminum acetylacetonate and stirring for 0.5h to obtain a uniform and stable organosilicon hydrophobic sol finishing solution.

(2) Immerse the PBO fiber into the organosilicon hydrophobic sol finishing solution obtained in step (1), take out the fiber after 0.5h, let it dry naturally at room temperature for 12h, and then place it in a drying oven at 90°C for cross-linking and curing for 2h , to obtain PBO fibers with a uniform hydrophobic coating on the surface.

In this example, the contact angle of the obtained PBO fiber was increased from 60.2° to 105.8° by using only silicone coating without adding UV absorber. After 110 hours under 1100w/ ^m2 ultraviolet light irradiation, the fiber strength retention rate was 61%. Under the conditions of no ultraviolet light irradiation, 80°C and 80% relative humidity, only the moisture and heat aging resistance of the fiber was investigated, and the fiber strength retention rate was 96% after 360 hours. Compared with Comparative Example 1, in the presence of the silicone coating, the moisture-heat aging resistance of the fiber is significantly improved, and the light aging resistance of the fiber is also improved to a certain extent.

Example 1

(1) Weigh 5mL tetraethyl orthosilicate, 25mL ethanol (EtOH) and 4mL hydrochloric acid (HCl) respectively, heat and mix them evenly at 25°C, add 7.5mL trimethoxyphenylsilane, and continue to stir at 25°C for 5h , to obtain a uniform and stable organosilicon hydrophobic sol finishing solution.

(2) Heat up the organosilicon hydrophobic sol obtained in step (1) to 60°C, add 0.08g of ultraviolet light absorber UV-9, and mix the ultraviolet light absorber and organosilicon hydrophobic sol evenly with the assistance of ultrasonic oscillation, and shake The time is 1 hour, and then cooled to room temperature, and a curing catalyst aluminum acetylacetonate is added to obtain a uniform and stable organosilicon hydrophobic sol composite finishing solution.

(3) Immerse the PBO fiber into the organosilicon hydrophobic sol composite finishing solution obtained in step (2) for 0.5h, then take out the fiber, dry it naturally at room temperature for 12h, and then place it in a drying oven at 90°C Combined curing for 2 hours to obtain PBO fibers with a uniform hydrophobic coating on the surface.

The PBO fiber obtained in this example has a strength retention rate of 75% after being irradiated with 1100w/m ² ultraviolet light for 110 hours. Under the conditions of no ultraviolet light irradiation, 80° C. and relative humidity of 80% humidity heat aging conditions, the fiber strength retention rate is 97% after 360 hours.

Example 2

This example differs from Example 1 in that perfluorotriethoxysilane is added instead of trimethoxyphenylsilane, and the others are the same as Comparative Example 1.

The strength retention rate of the PBO fiber obtained in this example is 84% after being irradiated with 1100w/m ² ultraviolet light for 110 hours. Under the conditions of no ultraviolet light irradiation, 80°C and 80% relative humidity under the conditions of damp heat aging, the fiber strength retention rate is 98% after 360 hours.

Example 3

The difference between this example and Example 1 is that the added ultraviolet light absorber is UV-531, and the others are the same as Comparative Example 1.

The PBO fiber obtained in this example has a strength retention rate of 78% after being irradiated with 1100w/m ² ultraviolet light for 110 hours. Under the conditions of no ultraviolet light irradiation, 80°C and 80% relative humidity under the conditions of heat and humidity aging, the fiber strength retention rate is 96% after 360 hours.

Example 4

The difference between this example and Example 1 is that the amount of UV-9 added is 0.12 g, and the others are the same as Comparative Example 1.

The PBO fiber obtained in this example has a strength retention rate of 79% after being irradiated with 1100w/m ² ultraviolet light for 110 hours. Under the conditions of no ultraviolet light irradiation, 80° C. and relative humidity of 80% humidity heat aging conditions, the fiber strength retention rate is 97% after 360 hours.

Example 5

The difference between this embodiment and Example 1 is that the added ultraviolet light absorber is a compound of UV-531 and UV-O in a mass ratio of 1:1, and the total amount of ultraviolet light absorber added is 0.20g. Others and comparative examples 1 is the same.

The PBO fiber obtained in this example has a strength retention rate of 81% after being irradiated with 1100w/m ² ultraviolet light for 110 hours. Under the conditions of no ultraviolet light irradiation, 80° C. and relative humidity of 80% humidity heat aging conditions, the fiber strength retention rate is 97% after 360 hours.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, some improvements and modifications can also be made, and these improvements and modifications should also be considered Within the protection scope of the present invention.

Claims (9)

1. a kind of preparation method of the PBO fiber that has anti-ultraviolet light and moisture-heat aging resistance concurrently, it is characterized in that, concrete steps are: (1) Heat and mix silica sol precursor, ethanol (EtOH) and hydrochloric acid (HCl) at 25-30°C respectively, add hydrophobic siloxane after mixing evenly, and continue to react at 25-30°C for 3~ 5h, to obtain a uniform and stable silicone hydrophobic sol; (2) Warm up the organic silicon hydrophobic sol obtained in step (1) to 40-80°C, add an ultraviolet light absorber, and mix the ultraviolet light absorber and organic silicon hydrophobic sol evenly with the assistance of ultrasonic oscillation, and the oscillation time is 0.5 ~2h, then cooled to room temperature, and added a curing catalyst to obtain a uniform and stable organosilicon hydrophobic sol composite finishing solution; (3) Immerse the PBO fiber into the organosilicon hydrophobic sol composite finishing solution obtained in step (2) for 0.5-2 hours, then take out the fiber, dry it naturally at room temperature for 12-48 hours, and place it in a drying box for 80-2 hours. Cross-linking and curing at 100°C for 2 to 5 hours to obtain PBO fibers with a uniform hydrophobic coating on the surface. 2. A kind of preparation method of the PBO fiber that has anti-ultraviolet light and heat and humidity resistance concurrently as claimed in claim 1, is characterized in that, in described step (1), described silica sol precursor is orthosilicon One of ethyl acetate and methyl orthosilicate. 3. the preparation method of a kind of PBO fiber with anti-ultraviolet light and moisture-heat aging resistance concurrently as claimed in claim 1, is characterized in that, in described step (1), described hydrophobic siloxane is tape Silicone with hydrophobic groups. 4. a kind of preparation method of the PBO fiber that has anti-ultraviolet light and heat and humidity resistance concurrently as claimed in claim 3 is characterized in that, the described siloxane with hydrophobic group is trimethoxyphenyl silane , Triethoxyphenylsilane, Perfluorotriethoxysilane, Methyltriethoxysilane, Methyltrimethoxysilane, Dodecyltrimethoxysilane, Hexadecyltrimethoxysilane, One of vinyltriethoxysilane and octyltriethoxysilane. 5. A kind of preparation method of the PBO fiber that has anti-ultraviolet light and heat and humidity resistance concurrently as claimed in claim 1, is characterized in that, in described step (1), described silica sol precursor, ethanol, The volume ratio of hydrochloric acid and hydrophobic siloxane is 1:5-10:0.05-1:1.5-5.0. 6. the preparation method of a kind of PBO fiber with anti-ultraviolet light and moisture-heat aging resistance concurrently as claimed in claim 1, is characterized in that, in described step (2), described ultraviolet light absorber is soluble UV absorber based on ethanol. 7. a kind of preparation method of the PBO fiber that has anti-ultraviolet light and heat and humidity resistance concurrently as claimed in claim 6, is characterized in that, described ultraviolet light absorber is UV-9, UV-328, UV-531 , UV-O, phenyl salicylate, UV absorber RMB or a mixture of several. 8. the preparation method of a kind of PBO fiber that has ultraviolet light resistance and moisture-heat aging resistance concurrently as claimed in claim 1, is characterized in that, in described step (2), the mass fraction of described ultraviolet light absorber It is 0.1%-2% relative to the total mass of the silicone hydrophobic sol. 9. A kind of preparation method of the PBO fiber that has anti-ultraviolet light and moisture-heat aging resistance concurrently as claimed in claim 1, is characterized in that, in described step (2), described curing catalyst is conventional organosilicon Coating crosslinking curing catalyst.