Glass fiber composite felt and preparation method thereof

Abstract

The invention discloses a glass fiber composite felt and a preparation method thereof. The glass fiber composite felt is formed by compounding a glass fiber continuous felt and a glass fiber chopped strand felt through a powder binder, the powder binder is prepared by mixing polyester resin, polypropylene oxide glycol and isophorone diisocyanate for reaction to obtain a prepolymer, and then introducing a heat stabilizer, a thermoplastic elastomer SEBS, sodium polyacrylate and a functional agent as auxiliaries for mixing reaction with the prepolymer. The glass fiber composite felt provided by the invention not only overcomes the defects of traditional continuous felts and chopped strand felts, but also improves the tensile breaking strength and weather resistance of the composite felt, so that the composite felt can be stably applied for a long time, and the wide application of the glass fiber composite felt is facilitated.

Description

Technical Field

[0001] This invention relates to the field of glass fiber mat technology, and in particular to a glass fiber composite mat and its preparation method. Background Technology

[0002] Fiberglass mat is a thin sheet-like product made by bonding dispersed chopped glass fiber filaments and continuous glass fiber bundles with a glass fiber binder at a certain temperature. Fiberglass mat can be used for heat insulation, thermal insulation, and fireproofing. Fiberglass mat includes chopped glass fiber mat (hereinafter referred to as chopped mat) and continuous glass fiber mat (hereinafter referred to as continuous mat). Chopped mat is made by shaving continuous glass fiber filaments and then laying them up, then bonding them with powder or latex binders. Its advantages include strong resin absorption capacity, good resin compatibility, convenient construction, and low cost. Therefore, it is often used in hand lay-up processes to produce fiberglass products such as fishing boats and cooling towers. However, the warp and weft strength of chopped mat is not as high as that of fiberglass fabric, making it prone to breakage during area construction and unsuitable for mechanized fiberglass molding processes. Continuous mat also uses continuous glass fiber filaments as raw material. It does not require chopped strands; instead, the continuous glass fiber filaments are directly thrown into loops without orientation using a filament-polishing device. The mat is formed by the mechanical action between the filament strands and the action of a small amount of powder binder. Its advantages include high mechanical properties and strength, and relatively uniform mat formation, making it suitable for large-scale mechanized molding processes such as pultrusion, filament winding, compression molding, and resin injection molding. However, continuous mat is more expensive and tends to entangle on the rollers during rolling, making it difficult to tear and unsuitable for hand lay-up fiberglass products.

[0003] To overcome the limitations of single-type fiberglass mats and meet the diverse production needs of fiberglass products, it is necessary to prepare fiberglass composite mats. By combining continuous mats and chopped strand mats, their different properties can be mutually integrated, achieving complementary advantages.

[0004] CN2523592Y discloses a glass fiber composite mat, which is composed of continuous glass fiber mat and chopped glass fiber mat bonded together with a powdered or emulsion resin binder. This composite mat overcomes the disadvantages of both types of mat while retaining their advantages, thus improving the strength and reducing the cost. However, the resin binder used in this composite mat has poor weather resistance, which can easily lead to a decline in the long-term stability of the composite mat.

[0005] CN1382856A discloses a glass fiber chopped strand / continuous filament composite mat and its manufacturing process. This glass fiber chopped strand / continuous filament composite mat is organically composed of two mat bodies: glass fiber chopped strand mat and glass fiber continuous filament mat. The weight percentages of the two mat bodies are: chopped strand mat accounts for 20%-80%, and continuous filament mat accounts for 80%-20%. This glass fiber chopped strand / continuous filament composite mat fully utilizes the advantages of both mat bodies and overcomes their respective disadvantages. However, its tensile breaking strength is relatively poor, which is not conducive to its practical application. Summary of the Invention

[0006] In view of the above-mentioned deficiencies of the prior art, the present invention provides a glass fiber composite mat and its preparation method. The glass fiber composite mat not only has good tensile breaking strength, but also good resistance to ultraviolet aging, which can achieve long-term stable application and is conducive to the widespread application of glass fiber composite mat.

[0007] To achieve the above objectives, the present invention provides a glass fiber composite mat, which is formed by combining two types of mats: continuous glass fiber mat and chopped glass fiber mat; the weight percentage of the two mats is 30%-70% for chopped glass fiber mat and 30%-70% for continuous glass fiber mat.

[0008] Preferably, the glass fiber composite mat further includes a powder binder, and the preparation method of the powder binder includes the following steps:

[0009] (1) First, the polyester resin and polypropylene glycol are vacuum dehydrated to a moisture content of ≤0.05% to obtain pretreated polyester resin and polypropylene glycol for later use; the pretreated polyester resin and polypropylene glycol are mixed, and then isophorone diisocyanate is added dropwise. After the addition, the mixture is kept warm and stirred to react; then the temperature is lowered, and dibutyltin dilaurate is added and stirred to obtain the prepolymer.

[0010] (2) Heat stabilizer, thermoplastic elastomer SEBS, sodium polyacrylate and functional agent are premixed to obtain a mixture; then the mixture is added to the prepolymer in step (1) above and mixed and stirred until uniform, then granulated by spray dryer and then sieved to obtain powder binder;

[0011] Preferably, the preparation method of the powder binder includes the following steps, in parts by weight:

[0012] (1) First, the polyester resin and polypropylene glycol are vacuum dehydrated to a moisture content of ≤0.05% under conditions of 95-105℃ and a vacuum degree of 0.08-0.09MPa, and then cooled to 55-65℃ to obtain pretreated polyester resin and polypropylene glycol for later use; the kneader is heated to 60-80℃, and 25-40 parts of the pretreated polyester resin and 15-25 parts of polypropylene glycol are added and mixed and stirred for 20-30 min; then 0.05-0.2 parts of dibutyltin dilaurate are added, and then 13-22 parts of isophorone diisocyanate are added dropwise at a uniform rate over 30-50 min through a dropping funnel. After the addition is completed, the mixture is stirred at 60-80℃ for 1-3 h to obtain the prepolymer;

[0013] (2) Premix 1.5-3 parts of heat stabilizer, 0.5-1 parts of thermoplastic elastomer SEBS, 0.2-0.5 parts of sodium polyacrylate and 1-3 parts of functional agent at 60-70℃ and 800-1000rpm for 10-20min to obtain a mixture; then add the mixture to the prepolymer in step (1) above, and mix and stir at 55-65℃ for 10-30min until uniform, then granulate by spray drying, and then pass through a 100-200 mesh sieve to obtain a powder binder;

[0014] Preferably, the heat stabilizer is selected from zinc oxide and calcium-zinc composite stabilizers.

[0015] Preferably, the functional agent is obtained by modifying oxidized nanocellulose with a silane coupling agent; or, it is obtained by modifying oxidized nanocellulose with one of adenine, 8-hydroxyadenine, 2,6-diaminopurine, and 2-chloro-6-aminopurine.

[0016] Preferably, the preparation method of the functional agent includes the following steps, in parts by weight:

[0017] Mix 1-3 parts of nanocellulose with 150-250 parts of water and stir for 0.5-1 h. Then add 0.1-0.2 parts of 2,2,6,6-tetramethylpiperidine oxide, 0.5-0.8 parts of sodium bromide, and 25-35 parts of sodium hypochlorite. Mix and react in a constant temperature water bath at 20-30℃ for 2-5 h. During the reaction, maintain the pH of the reaction system at 9.8-10.2 using 0.1-0.2 mol / L sodium hydroxide aqueous solution. After the reaction is complete, add 1-2 times the volume of anhydrous sodium hydroxide solution. Ethanol was added dropwise, followed by the addition of 0.1-0.2 mol / L dilute hydrochloric acid until the pH of the reaction solution reached 2-3. The solution was then dialyzed in water for 5-8 days. The dialyzed product was then freeze-dried to obtain oxidized nanocellulose. 1-10 parts of oxidized nanocellulose were ultrasonically treated with 90-110 parts of a 1-10 mg / mL KH-570 silane coupling agent ethanol solution at an ultrasonic power of 400-600 W for 30-60 min, and then dried at 40-60℃ for 6-12 h to obtain the final product.

[0018] Preferably, the preparation method of the functional agent includes the following steps, in parts by weight:

[0019] Mix 1-3 parts of nanocellulose with 150-250 parts of water and stir for 0.5-1 h. Then add 0.1-0.2 parts of 2,2,6,6-tetramethylpiperidine oxide, 0.5-0.8 parts of sodium bromide, and 25-35 parts of sodium hypochlorite. Mix and react in a constant temperature water bath at 20-30℃ for 2-5 h. During the reaction, maintain the pH of the reaction system at 9.8-10.2 using a 0.1-0.2 mol / L sodium hydroxide aqueous solution. After the reaction is complete, add 1-2 times the volume of anhydrous ethanol, and then add 0.1-0.2 mol / L dilute hydrochloric acid dropwise until the pH of the reaction solution is adjusted. The concentration was 2-3, and then dialyzed in water for 5-8 days. The dialyzed product was then freeze-dried to obtain oxidized nanocellulose. 0.3-0.5 parts of oxidized nanocellulose were mixed with 50-100 parts of water and then ultrasonically dispersed. 0.1-0.2 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.1-0.2 parts of N-hydroxysuccinimide were added, along with 0.1-0.5 parts of modifier. The mixture was stirred and reacted in a constant temperature water bath at 20-30℃ for 20-25 hours. The product was then centrifuged, washed with water 4-6 times, and vacuum dried to obtain the final product.

[0020] More preferably, the modifier is selected from one of adenine, 8-hydroxyadenine, 2,6-diaminopurine, and 2-chloro-6-aminopurine.

[0021] Preferably, the feed temperature of the spray drying operation is ≤80℃, the air inlet temperature is controlled at 150-200℃, the air outlet temperature is controlled at 60-90℃, and the particle size is controlled at 10-80μm.

[0022] The present invention also provides a method for preparing the above-mentioned glass fiber composite mat, comprising the following steps:

[0023] Step 1: First, produce glass fiber chopped strand mat blanks according to the glass fiber chopped strand mat production process requirements;

[0024] Step 2: According to the continuous glass fiber mat production process requirements, glass fibers are spun onto the above-mentioned glass fiber chopped strand mat blank to form a continuous glass fiber mat. Light pressure is applied to make it initially bonded to obtain the initial composite mat.

[0025] Step 3: Apply 0.6-1.2 g / m² of the initial composite felt area. 2 The single-layer dosage is to uniformly spray the powder binder onto the surface of the initial composite felt until the powder coverage is >90%; let it stand at room temperature for 8-15 minutes, then heat it to 120-150℃ and hot-press it for 6-12 minutes under 5-15MPa conditions; cool and demold to obtain glass fiber composite felt.

[0026] The beneficial effects of this invention are:

[0027] 1. Compared with existing technologies, this invention employs a dry hot-pressing composite process to prepare a glass fiber composite mat by combining continuous glass fiber mat and chopped glass fiber mat with a powder binder. The glass fiber composite mat provided by this invention not only overcomes the shortcomings of traditional continuous and chopped glass fiber mats but also improves the tensile strength and weather resistance of the composite mat, enabling long-term stable application and broadening the application fields of glass fiber composite mats.

[0028] 2. Compared with existing technologies, this invention reacts polyester resin and polypropylene glycol with isophorone diisocyanate to obtain a prepolymer. Then, a heat stabilizer, thermoplastic elastomer SEBS, sodium polyacrylate, and functional agents are introduced as additives and reacted with the prepolymer to finally prepare a powder binder. By spraying the powder binder onto the surface of glass fiber mat and curing it at high temperature, a glass fiber composite mat is prepared, resulting in significantly improved tensile strength and UV aging resistance. Detailed Implementation

[0029] The parameters for using specific chemical substances, and their sources.

[0030] Polyester resin, model: TS6666, sourced from Xiamen Aikema Chemical Co., Ltd.

[0031] Polypropylene glycol, molecular weight: 6000, specification: PPG-6000, sourced from Nantong Aojun Chemical Co., Ltd.

[0032] Nanocellulose, diameter: 5nm, length: 10nm, commercially available;

[0033] Thermoplastic elastomer SEBS, model: YH-503, is sourced from Changsha Shenli Chemical Technology Co., Ltd.

[0034] Sodium polyacrylate, molecular weight: 3000, brand: Wanhua Tianhe.

[0035] Example 1

[0036] A method for preparing a glass fiber composite mat includes the following steps:

[0037] Step 1: First, use a chopped strand machine to cut alkali-free glass fiber roving (diameter: 19μm, 1800tex, grade: 469H-1800, Chongqing International Composite Materials Co., Ltd.) into 40mm short fibers. Then, pass the fibers through a settling chamber with negative pressure air (negative pressure airflow 15000m³). 3 / h) to evenly distribute short fibers on the running mesh belt to form a glass fiber chopped strand mat blank with a thickness of 3mm, wherein the linear speed of the chopped strand mat is 125m / min and the running speed of the mesh belt is 8m / min;

[0038] Step 2: Using a polishing roller at a polishing linear speed of 85 m / min, alkali-free glass fiber direct untwisted roving (diameter: 15 μm, 735 tex, grade: 469H-735, Chongqing International Composite Materials Co., Ltd.) is polished into loops and dropped onto the glass fiber chopped strand mat blank to form a continuous glass fiber mat blank; then, a pressure roller (diameter: 150 mm, hardness: Shore A60, temperature: 60℃) is used to lightly press (pressure: 0.2 MPa) to make it initially bonded, thus obtaining the initial composite mat;

[0039] Step 3: Using electrostatic spraying equipment (electrostatic voltage 60kV, nozzle-to-felt distance 300mm, scanning speed 2m / min), apply the coating at a rate of 1g / m² according to the initial composite felt area. 2 The single-layer dosage is to uniformly spray the powder binder onto the surface of the initial composite felt until the powder coverage is 100%; after spraying, let it stand at room temperature for 10 minutes, and then hot-press and cure it at 130℃ and 10MPa for 10 minutes; cool it to below 80℃ and demold to obtain a glass fiber composite felt with a thickness of 6mm.

[0040] In the glass fiber composite mat prepared above, the weight percentage of continuous glass fiber mat and chopped glass fiber mat is 50% each.

[0041] The preparation method of the powder binder includes the following steps:

[0042] (1) Polyester resin and polypropylene glycol were vacuum dehydrated to ≤0.05% at 100℃ and 0.09MPa, and cooled to 60℃ to obtain pretreated polyester resin and polypropylene glycol for later use; the kneader was heated to 75℃, and 30 parts by weight of the pretreated polyester resin and 20 parts by weight of polypropylene glycol were added and mixed and stirred for 25 min; then 0.1 parts by weight of dibutyltin dilaurate were added, and then 16 parts by weight of isophorone diisocyanate were added dropwise at a uniform rate over 30 min through a dropping funnel. After the addition was completed, the mixture was stirred at 75℃ for 2 h to obtain the prepolymer.

[0043] (2) 2.5 parts by weight of zinc oxide, 0.8 parts by weight of thermoplastic elastomer SEBS, 0.4 parts by weight of sodium polyacrylate and 2.5 parts by weight of functional agent are premixed at 65°C and 900 rpm for 15 min to obtain a mixture; then the mixture is added to the prepolymer in step (1) above and mixed and stirred at 60°C for 20 min until uniform. Then it is granulated by spray drying under the conditions of feed temperature ≤80°C, air inlet temperature controlled at 160°C, air outlet temperature controlled at 60°C and particle size controlled at 50 μm. Then it is passed through a 200 mesh sieve to obtain a powder binder.

[0044] The preparation method of the functional agent includes the following steps:

[0045] 2.5 parts by weight of nanocellulose were mixed with 220 parts by weight of water and stirred for 0.5 h. Then, 0.15 parts by weight of 2,2,6,6-tetramethylpiperidine oxide, 0.6 parts by weight of sodium bromide, and 33 parts by weight of sodium hypochlorite were added, and the mixture was reacted in a constant temperature water bath at 28 °C for 3.5 h. During the reaction, the pH of the reaction system was maintained at 10 with 0.1 mol / L sodium hydroxide aqueous solution. After the reaction was completed, anhydrous ethanol with a volume equal to that of the reaction solution was added, and then 0.1 mol / L dilute hydrochloric acid was added dropwise until the pH of the reaction solution was 2.7. The solution was then dialyzed in water for 7 days. The dialyzed product was then freeze-dried to obtain oxidized nanocellulose. 1 part by weight of oxidized nanocellulose was ultrasonically treated with 100 parts by weight of KH-570 silane coupling agent ethanol solution with a concentration of 5 mg / mL at 500 W for 30 min, and then dried at 50 °C for 8 h to obtain the final product.

[0046] Example 2

[0047] The difference between the preparation method of the glass fiber composite mat and Example 1 is that the preparation method of the powder binder includes the following steps:

[0048] (1) Polyester resin and polypropylene glycol were vacuum dehydrated to ≤0.05% at 100℃ and 0.09MPa, and cooled to 60℃ to obtain pretreated polyester resin and polypropylene glycol for later use; the kneader was heated to 75℃, and 30 parts by weight of the pretreated polyester resin and 20 parts by weight of polypropylene glycol were added and mixed and stirred for 25 min; then 0.1 parts by weight of dibutyltin dilaurate were added, and then 16 parts by weight of isophorone diisocyanate were added dropwise at a uniform rate over 30 min through a dropping funnel. After the addition was completed, the mixture was stirred at 75℃ for 2 h to obtain the prepolymer.

[0049] (2) 2.5 parts by weight of zinc oxide, 0.8 parts by weight of thermoplastic elastomer SEBS, 0.4 parts by weight of sodium polyacrylate and 2.5 parts by weight of functional agent are premixed at 65°C and 900 rpm for 15 min to obtain a mixture; then the mixture is added to the prepolymer in step (1) above and mixed and stirred at 60°C for 20 min until uniform. Then it is granulated by spray drying under the conditions of feed temperature ≤80°C, air inlet temperature controlled at 160°C, air outlet temperature controlled at 60°C and particle size controlled at 50 μm. Then it is passed through a 200 mesh sieve to obtain a powder binder.

[0050] The preparation method of the functional agent includes the following steps:

[0051] 2.5 parts by weight of nanocellulose were mixed with 220 parts by weight of water and stirred for 0.5 h. Then, 0.15 parts by weight of 2,2,6,6-tetramethylpiperidine oxide, 0.6 parts by weight of sodium bromide, and 33 parts by weight of sodium hypochlorite were added. The mixture was then stirred in a constant temperature water bath at 28 °C for 3.5 h. During the reaction, the pH of the reaction system was maintained at 10 using a 0.1 mol / L sodium hydroxide aqueous solution. After the reaction was completed, anhydrous ethanol with a volume equal to that of the reaction solution was added, and then 0.1 mol / L dilute hydrochloric acid was added dropwise until the pH of the reaction solution reached 2. 0.7 parts by weight were then dialyzed in water for 7 days; the dialyzed product was then freeze-dried to obtain oxidized nanocellulose; 0.4 parts by weight of oxidized nanocellulose were mixed with 80 parts by weight of water, then ultrasonically dispersed, followed by the addition of 0.1 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.12 parts by weight of N-hydroxysuccinimide, and then 0.3 parts by weight of adenine. The mixture was stirred and reacted in a constant temperature water bath at 28°C for 22 hours; the product was then centrifuged, washed with water 4 times, and vacuum dried to obtain the final product.

[0052] Example 3

[0053] The difference between the preparation method of the glass fiber composite mat and Example 1 is that the preparation method of the powder binder includes the following steps:

[0054] (1) Polyester resin and polypropylene glycol were vacuum dehydrated to ≤0.05% at 100℃ and 0.09MPa, and cooled to 60℃ to obtain pretreated polyester resin and polypropylene glycol for later use; the kneader was heated to 75℃, and 30 parts by weight of the pretreated polyester resin and 20 parts by weight of polypropylene glycol were added and mixed and stirred for 25 min; then 0.1 parts by weight of dibutyltin dilaurate were added, and then 16 parts by weight of isophorone diisocyanate were added dropwise at a uniform rate over 30 min through a dropping funnel. After the addition was completed, the mixture was stirred at 75℃ for 2 h to obtain the prepolymer.

[0055] (2) 2.5 parts by weight of zinc oxide, 0.8 parts by weight of thermoplastic elastomer SEBS, 0.4 parts by weight of sodium polyacrylate and 2.5 parts by weight of functional agent are premixed at 65°C and 900 rpm for 15 min to obtain a mixture; then the mixture is added to the prepolymer in step (1) above and mixed and stirred at 60°C for 20 min until uniform. Then it is granulated by spray drying under the conditions of feed temperature ≤80°C, air inlet temperature controlled at 160°C, air outlet temperature controlled at 60°C and particle size controlled at 50 μm. Then it is passed through a 200 mesh sieve to obtain a powder binder.

[0056] The preparation method of the functional agent includes the following steps:

[0057] 2.5 parts by weight of nanocellulose were mixed with 220 parts by weight of water and stirred for 0.5 h. Then, 0.15 parts by weight of 2,2,6,6-tetramethylpiperidine oxide, 0.6 parts by weight of sodium bromide, and 33 parts by weight of sodium hypochlorite were added. The mixture was then stirred in a constant temperature water bath at 28 °C for 3.5 h. During the reaction, the pH of the reaction system was maintained at 10 using a 0.1 mol / L sodium hydroxide aqueous solution. After the reaction was completed, anhydrous ethanol with a volume equal to that of the reaction solution was added, followed by dropwise addition of 0.1 mol / L dilute hydrochloric acid until the pH of the reaction solution reached 2.7. The product was then dialyzed in water for 7 days. After that, the dialyzed product was freeze-dried to obtain oxidized nanocellulose. 0.4 parts by weight of oxidized nanocellulose was mixed with 80 parts by weight of water and then ultrasonically dispersed. Then, 0.1 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.12 parts by weight of N-hydroxysuccinimide were added, followed by 0.3 parts by weight of 8-hydroxyadenine. The mixture was stirred and reacted in a constant temperature water bath at 28°C for 22 hours. After that, the product was centrifuged, washed with water 4 times, and vacuum dried to obtain the final product.

[0058] Example 4

[0059] The difference between the preparation method of the glass fiber composite mat and Example 1 is that the preparation method of the powder binder includes the following steps:

[0060] (1) Polyester resin and polypropylene glycol were vacuum dehydrated to ≤0.05% at 100℃ and 0.09MPa, and cooled to 60℃ to obtain pretreated polyester resin and polypropylene glycol for later use; the kneader was heated to 75℃, and 30 parts by weight of the pretreated polyester resin and 20 parts by weight of polypropylene glycol were added and mixed and stirred for 25 min; then 0.1 parts by weight of dibutyltin dilaurate were added, and then 16 parts by weight of isophorone diisocyanate were added dropwise at a uniform rate over 30 min through a dropping funnel. After the addition was completed, the mixture was stirred at 75℃ for 2 h to obtain the prepolymer.

[0061] (2) 2.5 parts by weight of zinc oxide, 0.8 parts by weight of thermoplastic elastomer SEBS, 0.4 parts by weight of sodium polyacrylate and 2.5 parts by weight of functional agent are premixed at 65°C and 900 rpm for 15 min to obtain a mixture; then the mixture is added to the prepolymer in step (1) above and mixed and stirred at 60°C for 20 min until uniform. Then it is granulated by spray drying under the conditions of feed temperature ≤80°C, air inlet temperature controlled at 160°C, air outlet temperature controlled at 60°C and particle size controlled at 50 μm. Then it is passed through a 200 mesh sieve to obtain a powder binder.

[0062] The preparation method of the functional agent includes the following steps:

[0063] 2.5 parts by weight of nanocellulose were mixed with 220 parts by weight of water and stirred for 0.5 h. Then, 0.15 parts by weight of 2,2,6,6-tetramethylpiperidine oxide, 0.6 parts by weight of sodium bromide, and 33 parts by weight of sodium hypochlorite were added. The mixture was then stirred in a constant temperature water bath at 28 °C for 3.5 h. During the reaction, the pH of the reaction system was maintained at 10 using a 0.1 mol / L sodium hydroxide aqueous solution. After the reaction was completed, anhydrous ethanol with a volume equal to that of the reaction solution was added, followed by the dropwise addition of 0.1 mol / L dilute hydrochloric acid until the pH of the reaction solution reached 2.7. The product was then dialyzed in water for 7 days. After that, the dialyzed product was freeze-dried to obtain oxidized nanocellulose. 0.4 parts by weight of oxidized nanocellulose was mixed with 80 parts by weight of water and then ultrasonically dispersed. Then, 0.1 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.12 parts by weight of N-hydroxysuccinimide were added, followed by 0.3 parts by weight of 2-chloro-6-aminopurine. The mixture was stirred and reacted in a constant temperature water bath at 28°C for 22 hours. After that, the product was centrifuged, washed with water 4 times, and vacuum dried to obtain the final product.

[0064] Example 5

[0065] The difference between the preparation method of the glass fiber composite mat and Example 1 is that the preparation method of the powder binder includes the following steps:

[0066] (1) Polyester resin and polypropylene glycol were vacuum dehydrated to ≤0.05% at 100℃ and 0.09MPa, and cooled to 60℃ to obtain pretreated polyester resin and polypropylene glycol for later use; the kneader was heated to 75℃, and 30 parts by weight of the pretreated polyester resin and 20 parts by weight of polypropylene glycol were added and mixed and stirred for 25 min; then 0.1 parts by weight of dibutyltin dilaurate were added, and then 16 parts by weight of isophorone diisocyanate were added dropwise at a uniform rate over 30 min through a dropping funnel. After the addition was completed, the mixture was stirred at 75℃ for 2 h to obtain the prepolymer.

[0067] (2) 2.5 parts by weight of zinc oxide, 0.8 parts by weight of thermoplastic elastomer SEBS, 0.4 parts by weight of sodium polyacrylate and 2.5 parts by weight of functional agent are premixed at 65°C and 900 rpm for 15 min to obtain a mixture; then the mixture is added to the prepolymer in step (1) above and mixed and stirred at 60°C for 20 min until uniform. Then it is granulated by spray drying under the conditions of feed temperature ≤80°C, air inlet temperature controlled at 160°C, air outlet temperature controlled at 60°C and particle size controlled at 50 μm. Then it is passed through a 200 mesh sieve to obtain a powder binder.

[0068] The preparation method of the functional agent includes the following steps:

[0069] 2.5 parts by weight of nanocellulose were mixed with 220 parts by weight of water and stirred for 0.5 h. Then, 0.15 parts by weight of 2,2,6,6-tetramethylpiperidine oxide, 0.6 parts by weight of sodium bromide, and 33 parts by weight of sodium hypochlorite were added. The mixture was then stirred in a constant temperature water bath at 28 °C for 3.5 h. During the reaction, the pH of the reaction system was maintained at 10 using a 0.1 mol / L sodium hydroxide aqueous solution. After the reaction was completed, anhydrous ethanol with a volume equal to that of the reaction solution was added, and then 0.1 mol / L dilute hydrochloric acid was added dropwise until the pH of the reaction solution reached 2.7. The product was then dialyzed in water for 7 days. After dialyzing, the product was freeze-dried to obtain oxidized nanocellulose. 0.4 parts by weight of oxidized nanocellulose was mixed with 80 parts by weight of water and then ultrasonically dispersed. 0.1 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.12 parts by weight of N-hydroxysuccinimide were then added, followed by 0.3 parts by weight of 2,6-diaminopurine. The mixture was stirred and reacted in a constant temperature water bath at 28°C for 22 hours. The product was then centrifuged, washed with water 4 times, and vacuum dried to obtain the final product.

[0070] Comparative Example 1

[0071] The difference between the preparation method of the glass fiber composite mat and Example 1 is that the preparation method of the powder binder includes the following steps:

[0072] (1) Polyester resin and polypropylene glycol were vacuum dehydrated to ≤0.05% at 100℃ and 0.09MPa, and cooled to 60℃ to obtain pretreated polyester resin and polypropylene glycol for later use; the kneader was heated to 75℃, and 30 parts by weight of the pretreated polyester resin and 20 parts by weight of polypropylene glycol were added and mixed and stirred for 25 min; then 0.1 parts by weight of dibutyltin dilaurate were added, and then 16 parts by weight of isophorone diisocyanate were added dropwise at a uniform rate over 30 min through a dropping funnel. After the addition was completed, the mixture was stirred at 75℃ for 2 h to obtain the prepolymer.

[0073] (2) 2.5 parts by weight of zinc oxide, 0.8 parts by weight of thermoplastic elastomer SEBS, 0.4 parts by weight of sodium polyacrylate and 2.5 parts by weight of nanocellulose are premixed at 65°C and 900 rpm for 15 min to obtain a mixture; then the mixture is added to the prepolymer in step (1) above and mixed and stirred at 60°C for 20 min until uniform. Then it is granulated by spray drying under the conditions of feed temperature ≤80°C, air inlet temperature controlled at 160°C, air outlet temperature controlled at 60°C and particle size controlled at 50 μm. Then it is passed through a 200 mesh sieve to obtain a powder binder.

[0074] The nanocellulose is pretreated nanocellulose. The specific pretreatment operation is as follows: 1 part by weight of nanocellulose and 100 parts by weight of KH-570 silane coupling agent ethanol solution with a concentration of 5 mg / mL are ultrasonically treated at an ultrasonic power of 500 W for 30 min, and then dried at 50℃ for 8 h.

[0075] Comparative Example 2

[0076] The difference between the preparation method of the glass fiber composite mat and Example 1 is that the preparation method of the powder binder includes the following steps:

[0077] (1) Polyester resin and polypropylene glycol were vacuum dehydrated to ≤0.05% at 100℃ and 0.09MPa, and cooled to 60℃ to obtain pretreated polyester resin and polypropylene glycol for later use; the kneader was heated to 75℃, and 30 parts by weight of the pretreated polyester resin and 20 parts by weight of polypropylene glycol were added and mixed and stirred for 25 min; then 0.1 parts by weight of dibutyltin dilaurate were added, and then 16 parts by weight of isophorone diisocyanate were added dropwise at a uniform rate over 30 min through a dropping funnel. After the addition was completed, the mixture was stirred at 75℃ for 2 h to obtain the prepolymer.

[0078] (2) 2.5 parts by weight of zinc oxide, 0.8 parts by weight of thermoplastic elastomer SEBS and 0.4 parts by weight of sodium polyacrylate are premixed at 65°C and 900 rpm for 15 min to obtain a mixture; then the mixture is added to the prepolymer in step (1) above and mixed and stirred at 60°C for 20 min until uniform. Then, it is granulated by spray drying under the conditions of feed temperature ≤80°C, air inlet temperature controlled at 160°C, air outlet temperature controlled at 60°C and particle size controlled at 50 μm. Then, it is passed through a 200-mesh sieve to obtain a powder binder.

[0079] Test Example 1

[0080] The glass fiber composite mats prepared in Examples 1-5 and Comparative Examples 1-2 were used as test samples for performance testing. The specific test methods are as follows:

[0081] Tensile breaking strength test: The test was conducted according to the method provided in GB / T 6006.2-2013 Glass fiber mat Test Methods Part 2: Determination of tensile breaking strength. The test results are shown in Table 1 below.

[0082] UV aging test: Each composite felt sample was placed in an aging chamber and irradiated under a 340nm light source for 12h and 48h respectively, with the irradiance set to 200W / m². 2 The distance between the composite felt sample and the light source was adjusted to 300 mm, the ambient temperature was 25℃, and the relative humidity was 30%. After UV aging, the tensile breaking strength was measured again according to the above tensile breaking strength test method. The specific test results are shown in Table 1 below.

[0083] Table 1

[0084]

[0085] Table 1 shows that, comparing Examples 1-5 and Comparative Examples 1-2, the tensile breaking strength of Examples 1-5 is higher than that of Comparative Examples 1-2. This indicates that, compared with the addition of no functional agent or the addition of nanocellulose, the powder binder prepared using oxidized nanocellulose or modified oxidized nanocellulose as a functional agent is more beneficial to improving the tensile breaking strength of the composite felt. Comparing Examples 1-5, the tensile breaking strength of Examples 2-5 is higher than that of Example 1, and Example 5 has the highest tensile breaking strength. This indicates that, compared with the addition of oxidized nanocellulose as a functional agent, the powder binder prepared using adenine or adenine derivative-modified oxidized nanocellulose has a better effect on improving the tensile breaking strength of the composite felt. Furthermore, compared with the use of adenine, 8-hydroxyadenine, and 2-chloro-6-aminopurine-modified oxidized nanocellulose, the powder binder prepared using 2,6-diaminopurine-modified oxidized nanocellulose has a better effect on improving the tensile breaking strength of the composite felt. The reason for this may be that the introduction of the rigid structure of the purine ring of adenine is beneficial to improving the synergistic deformation ability of the matrix, thereby contributing to the improvement of tensile strength. Compared to 8-hydroxyadenine and 2-chloro-6-aminopurine, 2,6-diaminopurine contains two amino groups, which significantly increases the number of reaction sites, resulting in a higher grafting density. Furthermore, the amino groups have stronger nucleophilicity, allowing for a more complete reaction with the carboxyl groups of polyurethane, forming a dense interfacial cross-linking network. Therefore, it is more beneficial for improving tensile strength.

[0086] Table 1 shows that the tensile breaking strength of all examples and comparative examples decreased after 12h and 48h of UV aging. The decrease in tensile breaking strength of Examples 2-5 was less than that of Examples 1 and Comparative Examples 1-2, indicating that the powder binder prepared using modified oxidized nanocellulose as a functional agent is more beneficial for improving the UV aging resistance of the composite felt. Comparing Examples 2-5, the decrease in tensile breaking strength of Examples 3-4 after 12h of UV aging was less than that of Examples 2 and 5. After 48h of UV aging, compared to Examples 2-3 and 5, the tensile breaking strength of Examples 3-4... The tensile strength of Example 4 decreased significantly, indicating a marked decline in UV aging resistance. In contrast, Example 3 showed the smallest decrease in tensile strength and exhibited better UV aging resistance. This may be because the purine ring in the adenine molecule has UV absorption capabilities, shielding the polyurethane chain from UV degradation, thus increasing UV aging resistance. Furthermore, the 8-hydroxyl group in the 8-hydroxyadenine structure can form a hydrogen bond network with the soft segments of the polyurethane, enhancing the overall structural stability of the material. Simultaneously, the hydrogen bonding of the hydroxyl group can delay the photo-oxidation chain reaction, further improving UV aging resistance. Conversely, the electron-withdrawing effect of the chlorine atom in 2-chloro-6-aminopurine may alter the electron distribution of the purine ring, broadening the UV absorption range and initially providing good UV aging resistance. However, the introduction of chlorine may trigger a reaction, leading to poor long-term stability and a decline in UV aging resistance.

Claims

1. A glass fiber composite mat, characterized in that: It is formed by a composite of two types of mats: continuous glass fiber mat and chopped glass fiber mat; the weight percentage of the two mats is 30%-70% for chopped glass fiber mat and 30%-70% for continuous glass fiber mat. The glass fiber composite mat further includes a powder binder, and the preparation method of the powder binder includes the following steps: (1) First, the polyester resin and polypropylene glycol are vacuum dehydrated to a moisture content of ≤0.05% to obtain pretreated polyester resin and polypropylene glycol for later use; the pretreated polyester resin and polypropylene glycol are mixed, and then isophorone diisocyanate is added dropwise. After the addition, the mixture is kept warm and stirred to react; then the temperature is lowered, and dibutyltin dilaurate is added and stirred to obtain the prepolymer. (2) Heat stabilizer, thermoplastic elastomer SEBS, sodium polyacrylate and functional agent are premixed to obtain a mixture; then the mixture is added to the prepolymer in step (1) above and mixed and stirred until uniform, then granulated by spray dryer and then sieved to obtain powder binder; The functional agent is obtained by modifying oxidized nanocellulose with a silane coupling agent; or, it is obtained by modifying oxidized nanocellulose with one of adenine, 8-hydroxyadenine, 2,6-diaminopurine, or 2-chloro-6-aminopurine.

2. The glass fiber composite mat according to claim 1, characterized in that: The preparation method of the powder binder includes the following steps, in parts by weight: (1) First, the polyester resin and polypropylene glycol are vacuum dehydrated to ≤0.05% under conditions of 95-105℃ and vacuum degree of 0.08-0.09MPa, and cooled to 55-65℃ to obtain pretreated polyester resin and polypropylene glycol for later use; the kneader is heated to 60-80℃, and 25-40 parts of the pretreated polyester resin and 15-25 parts of polypropylene glycol are added and mixed and stirred for 20-30min; then 0.05-0.2 parts of dibutyltin dilaurate are added, and then 13-22 parts of isophorone diisocyanate are added dropwise at a uniform rate over 30-50min through a dropping funnel. After the addition is completed, the mixture is stirred at 60-80℃ for 1-3h to obtain the prepolymer. (2) 1.5-3 parts of heat stabilizer, 0.5-1 parts of thermoplastic elastomer SEBS, 0.2-0.5 parts of sodium polyacrylate and 1-3 parts of functional agent are premixed at 60-70℃ and 800-1000rpm for 10-20min to obtain a mixture; then the mixture is added to the prepolymer in step (1) above and mixed and stirred at 55-65℃ for 10-30min until uniform, then granulated by spray drying and then passed through a 100-200 mesh sieve to obtain a powder binder.

3. The glass fiber composite mat according to claim 1 or 2, characterized in that: The heat stabilizer is selected from zinc oxide and calcium-zinc composite stabilizers.

4. The glass fiber composite mat according to claim 1, characterized in that: The preparation method of the functional agent includes the following steps, in parts by weight: Mix 1-3 parts of nanocellulose with 150-250 parts of water and stir for 0.5-1 h. Then add 0.1-0.2 parts of 2,2,6,6-tetramethylpiperidine oxide, 0.5-0.8 parts of sodium bromide, and 25-35 parts of sodium hypochlorite. Mix and react in a constant temperature water bath at 20-30℃ for 2-5 h. During the reaction, maintain the pH of the reaction system at 9.8-10.2 using 0.1-0.2 mol / L sodium hydroxide aqueous solution. After the reaction is complete, add 1-2 times the volume of anhydrous sodium hydroxide solution. Ethanol was added dropwise, followed by the addition of 0.1-0.2 mol / L dilute hydrochloric acid until the pH of the reaction solution reached 2-3. The solution was then dialyzed in water for 5-8 days. The dialyzed product was then freeze-dried to obtain oxidized nanocellulose. 1-10 parts of oxidized nanocellulose were ultrasonically treated with 90-110 parts of a 1-10 mg / mL KH-570 silane coupling agent ethanol solution at an ultrasonic power of 400-600 W for 30-60 min, and then dried at 40-60℃ for 6-12 h to obtain the final product.

5. The glass fiber composite mat according to claim 1, characterized in that: The preparation method of the functional agent includes the following steps, in parts by weight: Mix 1-3 parts of nanocellulose with 150-250 parts of water and stir for 0.5-1 h. Then add 0.1-0.2 parts of 2,2,6,6-tetramethylpiperidine oxide, 0.5-0.8 parts of sodium bromide, and 25-35 parts of sodium hypochlorite. Mix and react in a constant temperature water bath at 20-30℃ for 2-5 h. During the reaction, maintain the pH of the reaction system at 9.8-10.2 using a 0.1-0.2 mol / L sodium hydroxide aqueous solution. After the reaction is complete, add 1-2 times the volume of anhydrous ethanol, and then add 0.1-0.2 mol / L dilute hydrochloric acid dropwise until the pH of the reaction solution is adjusted. The concentration was 2-3, and then dialyzed in water for 5-8 days. The dialyzed product was then freeze-dried to obtain oxidized nanocellulose. 0.3-0.5 parts of oxidized nanocellulose were mixed with 50-100 parts of water and then ultrasonically dispersed. 0.1-0.2 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.1-0.2 parts of N-hydroxysuccinimide were added, along with 0.1-0.5 parts of modifier. The mixture was stirred and reacted in a constant temperature water bath at 20-30℃ for 20-25 hours. The product was then centrifuged, washed with water 4-6 times, and vacuum dried to obtain the final product.

6. The glass fiber composite mat according to claim 6, characterized in that: The modifier is selected from one of adenine, 8-hydroxyadenine, 2,6-diaminopurine, and 2-chloro-6-aminopurine.

7. The glass fiber composite mat according to claim 1 or 2, characterized in that: The feed temperature of the spray drying operation is ≤80℃, the air inlet temperature is controlled at 150-200℃, the air outlet temperature is controlled at 60-90℃, and the particle size is controlled at 10-80μm.

8. A method for preparing a glass fiber composite mat as described in any one of claims 1-8, characterized in that, The following steps are involved: Step 1: First, produce glass fiber chopped strand mat blanks according to the glass fiber chopped strand mat production process requirements; Step 2: According to the continuous glass fiber mat production process requirements, glass fibers are spun onto the above-mentioned glass fiber chopped strand mat blank to form a continuous glass fiber mat. Light pressure is applied to make it initially bonded to obtain the initial composite mat. Step 3: Apply powder binder evenly to the surface of the initial composite felt at a single-layer dosage of 0.6-1.2 g / m² according to the initial composite felt area until the powder coverage is >90%; let stand at room temperature for 8-15 min, then heat to 120-150℃ and hot-press to cure at 5-15 MPa for 6-12 min; cool and demold to obtain glass fiber composite felt.

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