A hydrolysis-resistant glass fiber sizing agent, a preparation method and application thereof

Abstract

The present application relates to the technical field of glass fiber surface treatment, and particularly relates to a kind of hydrolysis-resistant glass fiber sizing agent and its preparation method and application, with the total mass of sizing agent as base, the mass percentage of each component is expressed as follows according to effective component solid content: 2,2'-1,3-phenylene bis 2-oxazoline 0.3 to 1.2%, epoxy functional siloxane modified polyurethane resin 3.0 to 5.5% when added in the form of emulsion is converted according to solid content, maleic anhydride modified polypropylene resin 1.5 to 3.0% when added in the form of emulsion is converted according to solid content, gamma-glycidyl ether oxypropyl trimethoxysilane 0.3 to 0.8%, N-phenyl-gamma-aminopropyl trimethoxysilane 0.1 to 0.5%, silicone 0.1 to 0.6%, polyether modified siloxane 0.05 to 0.3%, glacial acetic acid 0.02 to 0.1%, and the balance is deionized water. 2,2'-1,3-phenylene bis 2-oxazoline is used as hydrolysis-resistant agent, compared with carbodiimide hydrolysis-resistant agent, it has lower reaction activation energy and faster carboxyl capture rate.

Description

Technical Field

[0001] This invention relates to the field of glass fiber surface treatment technology, specifically to an anti-hydrolysis glass fiber wetting agent, its preparation method, and its application. Background Technology

[0002] Glass fiber, as a reinforcement in composite materials, has wide applications in the automotive, electronics, and aerospace industries. Sizing agents, specialized chemicals coated on the surface of nascent glass fibers, perform several core functions, including lubrication and protection, bundle formation, and interface modification. The performance of the sizing agent directly determines the processing properties of the glass fiber and the mechanical properties and durability of the composite materials it reinforces.

[0003] In humid and hot service environments, glass fiber reinforced composites face severe hydrolytic degradation problems. Water molecules penetrate the wetting agent film layer to reach the fiber-resin interface, leading to the following degradation pathways: water molecules hydrolyze and break the silicon-oxygen bonds formed between the silane coupling agent and the glass fiber surface, weakening the interfacial bonding force; ester and urethane bonds in the polymer chains of the film-forming agent in the wetting agent undergo hydrolytic chain breakage under humid and hot conditions, generating terminal carboxyl groups, which further ionize to release hydrogen ions, catalyzing the continuous degradation of surrounding polymer chains and forming a self-catalytic degradation cycle; water molecule intrusion into the interfacial region leads to plasticization of the resin matrix and etching of the fiber surface, ultimately resulting in a significant decrease in the mechanical properties of the composite material.

[0004] Existing patent publication number CN113860760A discloses a sizing agent for aging-resistant glass fibers, using carbodiimide hydrochloride or carbodiimide phosphate as an anti-hydrolysis agent, combined with polyurethane emulsion and maleic anhydride modified polyethylene emulsion as film-forming agents, and introducing crosslinking agents, light stabilizers, and antioxidants. In this scheme, carbodiimide blocks autocatalytic degradation by reacting with the terminal carboxyl groups generated by hydrolysis to form stable acylurea compounds. However, carbodiimide-based anti-hydrolysis agents have the following shortcomings: the reaction temperature of carbodiimide with carboxyl groups is relatively high, and the reaction rate is slow at the film-forming temperature of the sizing agent, making it unable to capture newly formed carboxyl groups in time during the early stage of film formation; carbodiimide has a low density, and it is easy to float and agglomerate in the water system of the sizing agent, resulting in uneven dispersion; carbodiimide can only passively capture the already generated carboxyl groups and cannot actively reduce the rate of water penetration into the interface region, resulting in a lag in anti-hydrolysis protection.

[0005] Existing patent publication number CN112573840A discloses a glass fiber impregnating agent that uses carbodiimide phosphate as an anti-hydrolysis agent and polypropylene emulsion and polyethylene emulsion as film-forming agents, suitable for reinforcing polypropylene composites. While the polyolefin film-forming agent in this scheme has a certain degree of hydrophobicity, the film density after formation is insufficient, and it cannot repair micro-defects through crosslinking under humid and hot conditions, resulting in limited long-term hydrolysis resistance.

[0006] Existing patent publication number CN117534342A discloses a glass fiber direct yarn sizing agent, which uses polymeric carbodiimide or isocyanate as an anti-hydrolysis agent, and is prepared in combination with a film-forming agent and a lubricant. Although isocyanate has high reactivity, it readily reacts with water to generate amines and carbon dioxide, making it difficult to exist stably in the aqueous system of the sizing agent, resulting in low utilization of the effective components in practical use.

[0007] In summary, the existing anti-hydrolysis schemes for glass fiber impregnating agents mainly rely on the terminal carboxyl group capture mechanism of carbodiimide compounds, which have shortcomings such as slow reaction rate, poor dispersibility, and delayed protection. Furthermore, the film-forming agent system lacks the ability to actively block water penetration and self-repair micro-defects. Summary of the Invention

[0008] The primary objective of this invention is to provide an anti-hydrolysis glass fiber impregnating agent, its preparation method, and its application.

[0009] A further object of the present invention is to provide a hydrolysis-resistant glass fiber sizing agent comprising an active ingredient and deionized water, wherein the solid content of the sizing agent is 5.4 to 12.0% by mass; based on the total mass of the sizing agent, the mass percentage of each component according to the solid content of the active ingredient is as follows: 0.3 to 1.2% 2,2'-1,3-phenylenebis-2-oxazoline, 3.0 to 5.5% epoxy-functionalized siloxane-modified polyurethane resin (calculated based on solid content when added in emulsion form), 1.5 to 3.0% maleic anhydride-modified polypropylene resin (calculated based on solid content when added in emulsion form), 0.3 to 0.8% γ-glycidyl etheroxypropyltrimethoxysilane, 0.1 to 0.5% N-phenyl-γ-aminopropyltrimethoxysilane, 0.1 to 0.6% organosilicone lubricant, and 0.05 to 0.3% polyether-modified siloxane wetting agent; further comprising 0.02 to 0.1% glacial acetic acid, with the balance being deionized water.

[0010] Preferably, based on the total mass of the wetting agent, the mass percentage of each component according to the solid content of the effective ingredient is as follows: 0.5 to 1.0% of 2,2'-1,3-phenylene bis-2-oxazoline; 3.0 to 5.0% of epoxy-functionalized siloxane-modified polyurethane resin (calculated based on solid content when added in emulsion form); 1.5 to 3.0% of maleic anhydride-modified polypropylene resin (calculated based on solid content when added in emulsion form); 0.4 to 0.7% of γ-glycidyl etheroxypropyltrimethoxysilane; 0.2 to 0.4% of N-phenyl-γ-aminopropyltrimethoxysilane; 0.2 to 0.5% of organosilicone lubricant; and 0.1 to 0.2% of polyether-modified siloxane wetting agent; it also includes 0.03 to 0.08% glacial acetic acid, with the balance being deionized water.

[0011] Preferably, the epoxy-functionalized siloxane-modified polyurethane resin emulsion has a solid content of 35 to 45% by mass, an epoxy value of 0.1 to 0.3 mol / 100g, and a siloxane segment mass fraction of 5 to 20%.

[0012] Preferably, the maleic anhydride-modified polypropylene resin emulsion has a solid content of 30 to 40% by mass, a maleic anhydride grafting rate of 1.5 to 3.0% by mass, and a weight-average molecular weight of 50,000 to 150,000.

[0013] Preferably, the mass ratio of γ-glycidoxypropyltrimethoxysilane to N-phenyl-γ-aminopropyltrimethoxysilane is 1.5:1 to 2.5:1.

[0014] Preferably, the purity of the 2,2'-1,3-phenylenebis-2-oxazoline is 97% by mass or higher.

[0015] A method for preparing the aforementioned hydrolysis-resistant glass fiber impregnating agent includes the following steps: Step 1: Add γ-glycidoxypropyltrimethoxysilane and N-phenyl-γ-aminopropyltrimethoxysilane to 10 to 20 parts by weight of deionized water, add glacial acetic acid to adjust the pH to 3.5 to 4.5, stir and hydrolyze for 30 to 50 minutes to obtain silane hydrolysate; Step 2: Dilute the silicone lubricant with 3 to 8 times its mass of deionized water and stir at room temperature for 10 to 20 minutes to obtain a lubricant dilution. Step 3: Add 2,2'-1,3-phenylenebis-2-oxazoline to the epoxy-functionalized siloxane-modified polyurethane resin emulsion, heat to 40 to 50°C and stir to dissolve for 20 to 30 minutes, then add 1 to 2 times the mass of the epoxy-functionalized siloxane-modified polyurethane resin emulsion with deionized water to dilute, stir for 10 to 15 minutes to obtain film-forming agent A dilution containing anti-hydrolysis agent; dilute maleic anhydride-modified polypropylene resin emulsion with 1 to 3 times the mass of deionized water and stir for 10 to 15 minutes to obtain film-forming agent B dilution. Step 4: Add the lubricant diluent to the preparation container, then add the film-forming agent B diluent, the film-forming agent A diluent containing the anti-hydrolysis agent, and the silane hydrolysis solution in sequence, and stir for 15 to 20 minutes to obtain the blend. Step 5: Dilute the polyether-modified siloxane wetting agent with 3 to 5 times its mass of deionized water and add it to the blend. Make up the remaining deionized water and stir for 20 to 30 minutes to obtain the hydrolysis-resistant glass fiber impregnating agent.

[0016] Preferably, the stirring speed in step one is 150 to 250 r / min, the stirring speed in step two is 100 to 200 r / min, the stirring speed in steps three and four is 150 to 250 r / min, and the stirring speed in step five is 150 to 250 r / min.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses 2,2'-1,3-phenylene bis-2-oxazoline as an anti-hydrolysis agent. Compared with carbodiimide anti-hydrolysis agents, it has a lower reaction activation energy and a faster carboxyl group capture rate, which can effectively block the autocatalytic degradation cycle in the early stage of film formation. Moreover, the planar rigid structure given by the 1,3-phenylene linking group makes the dispersion uniformity of bis-oxazoline in the wetting agent water system significantly better than that of carbodiimide.

[0018] 2. This invention uses epoxy-functionalized siloxane-modified polyurethane emulsion as the main film-forming agent. The surface migration and enrichment of siloxane segments on the film surface form a hydrophobic barrier, which effectively reduces the permeation rate of water molecules into the interface region. At the same time, epoxy groups participate in cross-linking to form a dense network. The dual effect significantly improves the water resistance of the film.

[0019] 3. In this invention, N-phenyl-γ-aminopropyltrimethoxysilane is used as one of the coupling agent components. The hydrophobic effect of the benzene ring reduces the water absorption rate of the interfacial region, and the conjugated structure of the benzene ring improves the hydrolytic stability of the silicon-oxygen bond. Furthermore, the amino group of this coupling agent undergoes a ring-opening reaction with the epoxy group in the epoxy-functionalized siloxane-modified polyurethane emulsion, thereby constructing a chemically bonded and reinforced interfacial layer on the fiber surface.

[0020] 4. The triple synergistic anti-hydrolysis mechanism of carboxyl group capture, hydrophobic barrier and self-crosslinking repair constructed in this invention produces a comprehensive anti-hydrolysis effect that exceeds the simple sum of the individual effects of each mechanism. The data from the examples show that the tensile strength retention rate of the composite material after 1000h of wet heat aging is more than 8 percentage points higher than that of the carbodiimide system and more than 13 percentage points higher than the best existing technology. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The inventive mechanism of this invention is as follows: This invention utilizes the synergistic effect of 2,2'-1,3-phenylenebis-2-oxazoline, epoxy-functionalized siloxane-modified polyurethane emulsion, and N-phenyl-γ-aminopropyltrimethoxysilane to construct a triple anti-hydrolysis mechanism of carboxyl group capture, hydrophobic barrier, and self-crosslinking repair.

[0023] (1) Carboxyl group capture: The 2,2'-1,3-phenylene bis-2-oxazoline molecule contains two oxazoline rings. The carbon-nitrogen double bond on the oxazoline ring is electrophilic and can undergo ring-opening addition reaction with the terminal carboxyl group generated by hydrolysis at a relatively low temperature to form a stable amide ester bond structure. Compared with carbodiimide, bisoxazoline has a lower activation energy and can react rapidly with carboxyl groups at the film-forming temperature of 110 to 130 °C when the wetting agent is dried. It can capture newly formed carboxyl groups in the early stage of film formation and promptly block the autocatalytic degradation cycle. At the same time, the 1,3-phenylene linking group gives the bisoxazoline molecule a good planar rigid structure, which is conducive to the uniform dispersion of the molecule in the wetting agent film layer without agglomeration and floating.

[0024] (2) Hydrophobic barrier: During the film formation process, the siloxane segments in the epoxy-functionalized siloxane-modified polyurethane emulsion migrate and accumulate to the film surface, forming a siloxane-rich hydrophobic surface layer. The bond energy of the siloxane bond in the siloxane segment is higher than that of the carbon-carbon bond, and the siloxane has extremely low surface energy, which increases the contact angle of water molecules on the film surface and significantly reduces the permeation rate. At the same time, the epoxy functional group undergoes a ring-opening reaction with the amino group of the aminosilane coupling agent during the film formation process, forming a dense cross-linked network on the fiber surface, further blocking water molecules from permeating along the interface.

[0025] (3) Self-crosslinking repair: The epoxy groups in the epoxy-functionalized siloxane modified polyurethane emulsion and the phenylamino groups in N-phenyl-γ-aminopropyltrimethoxysilane can undergo a secondary crosslinking reaction with the hydroxyl groups generated by hydrolysis in the film under humid and hot conditions.

[0026] When water molecules invade the membrane layer, causing some ester or urethane bonds to break, the newly generated hydroxyl groups are captured by the adjacent epoxy or silaneoxy groups, forming new crosslinking points in situ at the break site, thus achieving self-repair of micro-defects.

[0027] The hydrophobic effect of the benzene ring in N-phenyl-γ-aminopropyltrimethoxysilane further reduces the water absorption rate of the interfacial region, and the conjugated structure of the benzene ring improves the hydrolytic stability of the silicon-oxygen bond.

[0028] There are nonlinear synergistic effects among the mechanisms: Bisoxazoline timely captures carboxyl groups to block autocatalytic degradation, reducing the number of breakage sites in the polymer chains in the membrane layer, thereby reducing the water molecule flux that the hydrophobic barrier needs to block; the effective barrier of the hydrophobic barrier reduces the water concentration inside the membrane layer, slows down the hydrolysis reaction rate, and makes the capture capacity of bisoxazoline sufficient to deal with residual carboxyl groups; self-crosslinking repair seals micro-defects in the early stage of formation, preventing defects from expanding into through cracks and maintaining the integrity of the hydrophobic barrier.

[0029] Raw material source: 2,2'-1,3-Phenylidene bis-2-oxazoline, purity ≥97% by mass, CAS No. 64688-41-5, product of Shanghai Maclean Biochemical Technology Co., Ltd., brand name B865428; Epoxy-functionalized siloxane modified polyurethane emulsion, solid content 40% by mass, epoxy value 0.15 to 0.25 mol / 100g, siloxane segment mass fraction 8 to 15%, viscosity 200 to 500 mPa·s, pH 6.5 to 8.0, product of Wanhua Chemical Group Co., Ltd., brand name WAN-ESPU40. Maleic anhydride modified polypropylene emulsion, solid content 35% by mass, maleic anhydride grafting rate 1.5 to 3.0% by mass, weight average molecular weight 50,000 to 150,000, emulsion particle size 0.1 to 4.0 μm, polymer melting point 140 to 160 °C, pH 7.0 to 9.0, BYK Chemical Co., Ltd. product, brand name Aquacer 205RC1583; γ-glycidyl etheroxypropyltrimethoxysilane, purity ≥98% by mass, CAS No. 2530-83-8, Momentive Advanced Materials Group product, grade A-187; N-Phenyl-γ-aminopropyltrimethoxysilane, purity ≥95% by mass, CAS No. 3069-29-2, Momentive Advanced Materials Group product, grade Y-9669; γ-aminopropyltrimethoxysilane, purity ≥97% by mass, CAS No. 13822-56-5, Momentive Advanced Materials Group product, grade A-1110; γ-aminopropyltriethoxysilane, purity ≥98% by mass, CAS No. 919-30-2, Momentive Advanced Materials Group product, grade A-1100; Organosilicone lubricant, solid content 30% by mass, viscosity 80 to 150 mPa·s, pH 6.0 to 8.0, Dow Corning product, grade DC-346; Polyether-modified siloxane wetting agent, solid content 40% by mass, HLB value 12 to 15, pH 5.0 to 7.0, Evonik Industries product, brand name TEGO Wet 270; Polymerized carbodiimide, purity ≥98% by mass, CAS No. 30862-62-5, product of Lanxess Chemical Company, brand name Stabaxol P; 1-Ethyl-3-carbodiimine phosphate, purity ≥98% by mass, CAS No. 25879-93-0, product of Tokyo Chemical Industry Co., Ltd. Conventional polyester-type polyurethane emulsion, solid content 40% by mass, viscosity 200 to 500 mPa·s, pH 6.5 to 8.0, free of siloxane segments and epoxy functional groups, product of Wanhua Chemical Group Co., Ltd., grade WAN-PU40; Maleic anhydride modified polyethylene emulsion, solid content 35% by mass, maleic anhydride grafting rate 0.8 to 2.0% by mass, emulsion particle size 0.1 to 2.0 μm, pH 7.0 to 9.0, product of SK Chemicals Co., Ltd., South Korea, brand name SK-MAPE35; Polyethylene emulsion, solids content 35% by mass, weight average molecular weight 1000 to 20000, emulsion particle size 0.1 to 1.5 μm, pH 7.0 to 9.0, BYK Chemicals Ltd. product, brand name Aquacer 531; Glacial acetic acid, purity ≥ 99.5% by mass, CAS No. 64-19-7, product of Sinopharm Chemical Reagent Co., Ltd. Deionized water, resistivity greater than 18 MΩ·cm, homemade.

[0030] Example 1:

[0031] Raw material formula: 0.7% by weight of 2,2'-1,3-phenylenebis-2-oxazoline, 4.0% by weight of epoxy-functionalized siloxane-modified polyurethane resin, 2.0% by weight of maleic anhydride-modified polypropylene resin, 0.5% by weight of γ-glycidyl etheroxypropyltrimethoxysilane, 0.3% by weight of N-phenyl-γ-aminopropyltrimethoxysilane, 0.3% by weight of organosilicone, 0.15% by weight of polyether-modified siloxane, 0.05% by weight of glacial acetic acid, with the balance being deionized water.

[0032] The epoxy-functionalized siloxane-modified polyurethane resin was added in the form of an emulsion with a solid content of 40% by mass, which is equivalent to an emulsion addition of 10.0% by mass; the maleic anhydride-modified polypropylene resin was added in the form of an emulsion with a solid content of 35% by mass, which is equivalent to an emulsion addition of 5.71% by mass; the organosilicone was added in the form of an emulsion with a solid content of 30% by mass, which is equivalent to an emulsion addition of 1.0% by mass; and the polyether-modified siloxane was added in the form of a solution with a solid content of 40% by mass, which is equivalent to an addition of 0.375% by mass.

[0033] Preparation process: Step 1: Add γ-glycidoxypropyltrimethoxysilane and N-phenyl-γ-aminopropyltrimethoxysilane to 15 parts by mass of deionized water, add glacial acetic acid to adjust the pH to 4.0, and stir at 200 r / min for 40 min to hydrolyze and obtain silane hydrolysate. Step 2: Dilute the silicone lubricant with 5 times its mass of deionized water, and stir at 150 r / min for 15 min at room temperature (25°C) to obtain the lubricant dilution. Step 3: Add 2,2'-1,3-phenylenebis-2-oxazoline to the epoxy-functionalized siloxane-modified polyurethane emulsion, heat to 45°C and stir at 200 r / min for 25 min to dissolve, then add twice the mass of deionized water to dilute and stir for 12 min to obtain film-forming agent A dilution containing anti-hydrolysis agent; dilute maleic anhydride-modified polypropylene emulsion with twice the mass of deionized water and stir for 12 min to obtain film-forming agent B dilution. Step 4: Add the lubricant diluent to a stainless steel preparation container, then add the film-forming agent B diluent, the film-forming agent A diluent containing the anti-hydrolysis agent, and the silane hydrolysate in sequence. Stir at 200 r / min for 18 min to obtain a blend. Step 5: Dilute the polyether-modified siloxane wetting agent with 4 times its mass of deionized water and add it to the blend. Make up the remaining deionized water and stir at 200 r / min for 25 min to obtain the hydrolysis-resistant glass fiber impregnating agent.

[0034] In this embodiment, the solid content of the wetting agent is 8.0% by mass.

[0035] Example 2:

[0036] Raw material formulation: 1.0% by weight of 2,2'-1,3-phenylenebis-2-oxazoline, 5.0% by weight of epoxy-functionalized siloxane-modified polyurethane resin, 2.5% by weight of maleic anhydride-modified polypropylene resin, 0.6% by weight of γ-glycidyl etheroxypropyltrimethoxysilane, 0.35% by weight of N-phenyl-γ-aminopropyltrimethoxysilane, 0.4% by weight of organosilicone, 0.18% by weight of polyether-modified siloxane, 0.06% by weight of glacial acetic acid, with the balance being deionized water.

[0037] The actual amount of emulsion raw materials added is calculated based on the solid content of the product, and the calculation method is the same as in Example 1.

[0038] The preparation process is the same as in Example 1.

[0039] In this embodiment, the solid content of the wetting agent is 10.09% by mass.

[0040] Example 3:

[0041] Raw material formulation: 0.5% by weight of 2,2'-1,3-phenylenebis-2-oxazoline, 3.0% by weight of epoxy-functionalized siloxane-modified polyurethane resin, 1.5% by weight of maleic anhydride-modified polypropylene resin, 0.4% by weight of γ-glycidyl etheroxypropyltrimethoxysilane, 0.2% by weight of N-phenyl-γ-aminopropyltrimethoxysilane, 0.25% by weight of organosilicone, 0.1% by weight of polyether-modified siloxane, 0.04% by weight of glacial acetic acid, with the balance being deionized water.

[0042] The actual amount of emulsion raw materials added is calculated based on the solid content of the product, and the calculation method is the same as in Example 1.

[0043] The preparation process is the same as in Example 1.

[0044] In this embodiment, the solid content of the wetting agent is 5.99% by mass.

[0045] Example 4:

[0046] Raw material formulation: 0.8% by mass of 2,2'-1,3-phenylenebis-2-oxazoline, 4.5% by mass of epoxy-functionalized siloxane-modified polyurethane resin, 3.0% by mass of maleic anhydride-modified polypropylene resin, 0.7% by mass of γ-glycidyl etheroxypropyltrimethoxysilane, 0.4% by mass of N-phenyl-γ-aminopropyltrimethoxysilane, 0.45% by mass of organosilicone, 0.2% by mass of polyether-modified siloxane, 0.07% by mass of glacial acetic acid, with the balance being deionized water.

[0047] The actual amount of emulsion raw materials added is calculated based on the solid content of the product, and the calculation method is the same as in Example 1.

[0048] The preparation process is the same as in Example 1.

[0049] In this embodiment, the solid content of the wetting agent is 10.12% by mass.

[0050] Example 5:

[0051] Raw material formulation: 0.6% by mass of 2,2'-1,3-phenylenebis-2-oxazoline, 3.5% by mass of epoxy-functionalized siloxane-modified polyurethane resin, 1.8% by mass of maleic anhydride-modified polypropylene resin, 0.5% by mass of γ-glycidyl etheroxypropyltrimethoxysilane, 0.25% by mass of N-phenyl-γ-aminopropyltrimethoxysilane, 0.3% by mass of organosilicone, 0.12% by mass of polyether-modified siloxane, 0.05% by mass of glacial acetic acid, with the balance being deionized water.

[0052] The actual amount of emulsion raw materials added is calculated based on the solid content of the product, and the calculation method is the same as in Example 1.

[0053] The preparation process is the same as in Example 1.

[0054] In this embodiment, the solid content of the wetting agent is 7.12% by mass.

[0055] Comparative Example 1: The raw material formulation does not contain 2,2'-1,3-phenylenebis-2-oxazoline, so this component is omitted. The remaining components and their amounts are the same as in Example 1.

[0056] In the preparation process, the addition of 2,2'-1,3-phenylenebis-2-oxazoline in step three is omitted. The epoxy-functionalized siloxane-modified polyurethane emulsion is directly diluted and used. The remaining steps are the same as in Example 1.

[0057] The solid content of the wetting agent in this comparative example is 7.3% by mass.

[0058] Comparative Example 2: In the raw material formulation, 2,2'-1,3-phenylenebis-2-oxazoline was replaced with an equivalent amount of polymeric carbodiimide, and the remaining components and amounts were the same as in Example 1.

[0059] In the preparation process, 2,2'-1,3-phenylenebis-2-oxazoline was replaced with polymeric carbodiimide, which was added to an epoxy-functionalized siloxane-modified polyurethane emulsion and stirred at 45°C for 25 min to dissolve. The remaining steps were the same as in Example 1.

[0060] The solid content of the wetting agent in this comparative example is 8.0% by mass.

[0061] Comparative Example 3: In the raw material formulation, the epoxy-functionalized siloxane-modified polyurethane resin was replaced with an equivalent amount of conventional polyester-type polyurethane resin, and added in the form of WAN-PU40 emulsion with a solid content of 40% by mass. It does not contain siloxane segments and epoxy functional groups, and the remaining components and amounts are the same as in Example 1.

[0062] In the preparation process, 2,2'-1,3-phenylenebis-2-oxazoline was added to a conventional polyester polyurethane emulsion and stirred at 45°C for 25 minutes to dissolve. The remaining steps were the same as in Example 1.

[0063] The solid content of the wetting agent in this comparative example is 8.0% by mass.

[0064] Comparative Example 4: The raw material formula is as follows: 4.0% by weight of polyester polyurethane resin, 2.0% by weight of maleic anhydride modified polyethylene resin, 0.7% by weight of polymeric carbodiimide, 0.8% by weight of γ-aminopropyltriethoxysilane, 0.3% by weight of organosilicone, 0.05% by weight of glacial acetic acid, and the balance being deionized water.

[0065] The formulation was designed with reference to the technical solution of CN113860760B, in which polyester polyurethane resin was added with WAN-PU40 emulsion, maleic anhydride modified polyethylene resin was added with SK-MAPE35 emulsion, and γ-aminopropyltriethoxysilane was added with Momentive A-1100 product.

[0066] Preparation process: Add γ-aminopropyltriethoxysilane to deionized water, add glacial acetic acid to adjust the pH to 4.0, and stir for 40 min to hydrolyze; dilute the organosilicone lubricant with 5 times its mass of deionized water and stir for 15 min; dilute the polyester polyurethane emulsion and maleic anhydride modified polyethylene emulsion with 2 times their mass of deionized water and stir for 12 min; add polymeric carbodiimide to the polyester polyurethane emulsion and stir at 45℃ for 25 min to dissolve; mix the diluents sequentially, add deionized water to make up the volume, and stir for 25 min.

[0067] The solid content of the wetting agent in this comparative example is 7.85% by mass.

[0068] Comparative Example 5: The raw material formula is as follows: 5.0% by mass of polypropylene resin, 2.5% by mass of polyethylene resin, 0.7% by mass of 1-ethyl-3-carbodiimide phosphate, 0.5% by mass of γ-aminopropyltrimethoxysilane, 0.3% by mass of organosilicone, 0.05% by mass of glacial acetic acid, and the balance being deionized water.

[0069] The formulation was designed with reference to the technical solution of CN112573840A, in which polypropylene resin was added with Aquacer205RC1583 emulsion and polyethylene resin was added with Aquacer531 emulsion.

[0070] Preparation process: Add γ-aminopropyltrimethoxysilane to deionized water, adjust the pH to 4.0 with glacial acetic acid, and stir for 40 min to hydrolyze; dilute the organosilicone lubricant with 5 times its mass of deionized water and stir for 15 min; dilute the polypropylene emulsion and polyethylene emulsion with 2 times their mass of deionized water and stir for 12 min; dissolve 1-ethyl-3-carbodiimide phosphate with 8 times its mass of deionized water at 50℃ and stir for 25 min; mix the diluents sequentially, add deionized water to make up the volume, and stir for 25 min.

[0071] The solid content of the wetting agent in this comparative example is 9.05% by mass.

[0072] Comparative Example 6: In this comparative example, N-phenyl-γ-aminopropyltrimethoxysilane was replaced with an equal effective amount of γ-aminopropyltrimethoxysilane, while the remaining components and amounts were the same as in Example 1. This comparative example was used to verify the irreplaceable nature of the hydrophobic effect of the benzene ring in N-phenyl-γ-aminopropyltrimethoxysilane.

[0073] In the preparation process, N-phenyl-γ-aminopropyltrimethoxysilane was replaced with γ-aminopropyltrimethoxysilane, and hydrolyzed together with γ-glycidoxypropyltrimethoxysilane in deionized water. The remaining steps were the same as in Example 1.

[0074] The solid content of the wetting agent in this comparative example is 8.0% by mass.

[0075] Comparative Example 7: In the raw material formulation, the epoxy-functionalized siloxane modified polyurethane resin was replaced with an equal effective amount of conventional polyester polyurethane resin, and N-phenyl-γ-aminopropyltrimethoxysilane was replaced with an equal effective amount of γ-aminopropyltrimethoxysilane. The remaining components and amounts were the same as in Example 1.

[0076] This comparative example is used to verify the synergistic necessity of epoxy-functionalized siloxane film-forming agent and phenylaminosilane in the triple synergistic mechanism of the present invention.

[0077] In the preparation process, 2,2'-1,3-phenylenebis-2-oxazoline was added to a conventional polyester polyurethane emulsion and stirred at 45°C for 25 min to dissolve. In the silane hydrolysate, γ-aminopropyltrimethoxysilane was used instead of N-phenyl-γ-aminopropyltrimethoxysilane. The remaining steps were the same as in Example 1.

[0078] The solid content of the wetting agent in this comparative example is 8.0% by mass.

[0079] Performance testing and results analysis: The sizing agents prepared in the various examples and comparative examples were used to coat E-glass fiber rovings with a fiber diameter of 13 μm. After coating, the rovings were dried at 120°C for 2 min. The coated glass fibers were then chopped to a length of 4 mm and blended with polyamide 6 resin at a fiber content of 30% by mass to prepare standard samples via injection molding.

[0080] Polyamide 6 resin grade M2274, relative viscosity 2.6 to 3.0, BASF AG product.

[0081] The test items and conditions are as follows: Tensile strength: Performed in accordance with ISO527-1:2019, using a ZwickRoellZ020 universal testing machine, with a loading rate of 5 mm / min and a test temperature of 23℃, and taking the average value of 5 tests per group; Bending strength: Performed in accordance with ISO14125:1998, span 64mm, loading rate 2mm / min, test temperature 23℃, average value of 5 tests per group; Interfacial shear strength: Performed according to GB / T30969 microbead debonding method, test temperature 23℃, 10 tests per group and average value taken; Damp heat aging conditions: 85℃ / 85% relative humidity, aging time 1000h, in accordance with GB / T2573; Water absorption rate: Performed in accordance with ISO 62:2008, sample size 50mm×50mm×2mm, soaked at 23℃ for 24h.

[0082] Table 1. Test results of dry mechanical properties of composite materials:

[0083] Table 2. Test results of mechanical properties and retention rate of composite materials after damp heat aging:

[0084] Test methods: Tensile strength, flexural strength, and interfacial shear strength are tested using the same methods as above; damp heat aging conditions are 85℃ / 85% relative humidity, aging time is 1000h; water absorption rate is performed according to ISO62:2008, sample size is 50mm×50mm×2mm, soaked at 23℃ for 24h; retention rate / % = performance value after aging ÷ performance value before aging × 100%.

[0085] Results analysis: After aging, the tensile strength retention rate of Examples 1 to 5 was 87.9% to 89.8%, the flexural strength retention rate was 87.1% to 90.2%, the interfacial shear strength retention rate was 83.8% to 85.9%, and the water absorption rate was 0.68% to 0.79%.

[0086] Comparative Example 1, which did not contain an anti-hydrolysis agent, retained 66.0% of its tensile strength after aging, a difference of 23.0 percentage points from 89.0% in Example 1. This indicates that the anti-hydrolysis agent is crucial for the composite material's resistance to damp heat. It was also noted that the dry tensile strength of Comparative Example 1 (165.8 MPa) was close to that of Example 1 (168.3 MPa), suggesting that 2,2'-1,3-phenylenebis-2-oxazoline, as an anti-hydrolysis agent, has a limited impact on dry mechanical properties; its core function lies in protection against damp heat aging.

[0087] Comparative Example 2, which used polymerized carbodiimide instead of bisoxazoline, achieved a stretch retention rate of 81.0%, which was 8.0 percentage points lower than that of Example 1. This indicates that bisoxazoline has a significantly higher carboxyl group capture efficiency in the wetting agent system than carbodiimide. This difference stems from the fact that bisoxazoline's lower activation energy allows it to react faster at the film-forming temperature, enabling it to capture terminal carboxyl groups in the early stages of hydrolysis.

[0088] Comparative Example 3 used a conventional polyurethane emulsion instead of the epoxy-functionalized siloxane-modified polyurethane emulsion, and the tensile retention rate was 78.0%, which was 11.0 percentage points lower than that of Example 1. This indicates that the hydrophobic barrier and self-crosslinking repair provided by the epoxy-functionalized siloxane film-forming agent significantly contribute to the hydrolysis resistance performance.

[0089] Comparative Example 6 replaced N-phenyl-γ-aminopropyltrimethoxysilane with conventional γ-aminopropyltrimethoxysilane, and the tensile retention rate was 86.0%, which was 3.0 percentage points lower than that of Example 1. This indicates that the interfacial hydrophobic enhancement effect of the benzene ring in phenylaminosilane has an undeniable contribution to the hydrolysis resistance.

[0090] Comparative Example 7, which simultaneously replaced both the epoxy-functionalized siloxane film-forming agent and phenylaminosilane, had a tensile retention rate of 72.1%, which was 5.9 percentage points lower than that of Comparative Example 3 and 13.9 percentage points lower than that of Comparative Example 6. This indicates that the interfacial hydrophobic enhancement effect of phenylaminosilane is more critical when a hydrophobic barrier is absent, and vice versa, and there is a synergistic enhancement relationship between the two.

[0091] Comparative Examples 4 and 5, which adopted existing technical solutions, had tensile retention rates of 75.5% and 72.0%, respectively, both significantly lower than those of the Example.

[0092] Further comparison shows that Comparative Example 6, which combines bisoxazoline with an epoxy-functionalized siloxane film-forming agent but uses conventional aminosilane, achieved a tensile retention rate of 86.0%, which is significantly better than the prior art, but still lower than the 89.0% of Example 1. This indicates that the interfacial hydrophobic enhancement of phenylaminosilane is an indispensable component in the triple mechanism.

[0093] Comparative Example 7 combined bisoxazoline with conventional film-forming agents and conventional coupling agents, and the stretch retention rate was 72.1%, which is close to that of Comparative Example 5 of the prior art. This indicates that bisoxazoline cannot fully exert its carboxyl group capture efficiency in conventional systems that lack hydrophobic barriers and enhanced interfacial hydrophobicity.

[0094] Based on the above data, each component in the triple synergistic mechanism of this invention is irreplaceable, and the absence of any one component leads to a significant decrease in tensile retention rate.

[0095] The difference of 3.0 percentage points between Example 1 and Comparative Example 6, the difference of 8.0 percentage points between Example 1 and Comparative Example 2, and the difference of 11.0 percentage points between Example 1 and Comparative Example 3, when superimposed, exceed the simple sum of the differences of each group, exhibiting a significant nonlinear synergistic gain effect.

[0096] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A hydrolysis-resistant glass fiber impregnating agent, characterized in that, The wetting agent comprises active ingredients and deionized water, with a solid content of 5.4 to 12.0% by mass. Based on the total mass of the wetting agent, the mass percentages of each component according to the solid content of the active ingredient are as follows: 0.3 to 1.2% 2,2'-1,3-phenylene bis-2-oxazoline; 3.0 to 5.5% epoxy-functionalized siloxane-modified polyurethane resin (calculated based on solid content when added in emulsion form); 1.5 to 3.0% maleic anhydride-modified polypropylene resin (calculated based on solid content when added in emulsion form); 0.3 to 0.8% γ-glycidyl etheroxypropyltrimethoxysilane; 0.1 to 0.5% N-phenyl-γ-aminopropyltrimethoxysilane; 0.1 to 0.6% organosilicone lubricant; 0.05 to 0.3% polyether-modified siloxane wetting agent; and also includes 0.02 to 0.1% glacial acetic acid, with the balance being deionized water.

2. The anti-hydrolysis glass fiber impregnating agent as described in claim 1, characterized in that, Based on the total mass of the wetting agent, the mass percentage of each component according to the solid content of the effective ingredient is as follows: 2,2'-1,3-phenylene bis-2-oxazoline 0.5 to 1.0%; epoxy-functionalized siloxane-modified polyurethane resin (when added in emulsion form, calculated based on solid content) 3.0 to 5.0%; maleic anhydride-modified polypropylene resin (when added in emulsion form, calculated based on solid content) 1.5 to 3.0%; γ-glycidyl etheroxypropyltrimethoxysilane 0.4 to 0.7%; N-phenyl-γ-aminopropyltrimethoxysilane 0.2 to 0.4%; organosilicone lubricant 0.2 to 0.5%; polyether-modified siloxane wetting agent 0.1 to 0.2%; also includes glacial acetic acid 0.03 to 0.08%, with the balance being deionized water.

3. The anti-hydrolysis glass fiber impregnating agent as described in claim 1, characterized in that, The epoxy-functionalized siloxane-modified polyurethane resin emulsion has a solid content of 35 to 45% by mass, an epoxy value of 0.1 to 0.3 mol / 100g, and a siloxane segment mass fraction of 5 to 20%.

4. The anti-hydrolysis glass fiber impregnating agent as described in claim 1, characterized in that, The maleic anhydride-modified polypropylene resin emulsion has a solid content of 30 to 40% by mass, a maleic anhydride grafting rate of 1.5 to 3.0% by mass, and a weight-average molecular weight of 50,000 to 150,000.

5. The anti-hydrolysis glass fiber impregnating agent as described in claim 1, characterized in that, The mass ratio of γ-glycidoxypropyltrimethoxysilane to N-phenyl-γ-aminopropyltrimethoxysilane is 1.5:1 to 2.5:

1.

6. The anti-hydrolysis glass fiber impregnating agent as described in claim 1, characterized in that, The purity of the 2,2'-1,3-phenylenebis-2-oxazoline is above 97% by mass.

7. A method for preparing an anti-hydrolysis glass fiber impregnating agent as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Add γ-glycidoxypropyltrimethoxysilane and N-phenyl-γ-aminopropyltrimethoxysilane to 10 to 20 parts by weight of deionized water, add glacial acetic acid to adjust the pH to 3.5 to 4.5, stir and hydrolyze for 30 to 50 minutes to obtain silane hydrolysate; Step 2: Dilute the silicone lubricant with 3 to 8 times its mass of deionized water and stir at room temperature for 10 to 20 minutes to obtain a lubricant dilution. Step 3: Add 2,2'-1,3-phenylenebis-2-oxazoline to the epoxy-functionalized siloxane-modified polyurethane resin emulsion, heat to 40 to 50°C and stir to dissolve for 20 to 30 minutes, then add 1 to 2 times the mass of the epoxy-functionalized siloxane-modified polyurethane resin emulsion with deionized water to dilute, stir for 10 to 15 minutes to obtain film-forming agent A dilution containing anti-hydrolysis agent; dilute maleic anhydride-modified polypropylene resin emulsion with 1 to 3 times the mass of deionized water and stir for 10 to 15 minutes to obtain film-forming agent B dilution. Step 4: Add the lubricant diluent to the preparation container, then add the film-forming agent B diluent, the film-forming agent A diluent containing the anti-hydrolysis agent, and the silane hydrolysis solution in sequence, and stir for 15 to 20 minutes to obtain the blend. Step 5: Dilute the polyether-modified siloxane wetting agent with 3 to 5 times its mass of deionized water and add it to the blend. Make up the remaining deionized water and stir for 20 to 30 minutes to obtain the hydrolysis-resistant glass fiber impregnating agent.

8. The method for preparing the anti-hydrolysis glass fiber impregnating agent as described in claim 7, characterized in that, The stirring speed is 150 to 250 r / min in step one, 100 to 200 r / min in step two, 150 to 250 r / min in steps three and four, and 150 to 250 r / min in step five.

9. The application of a glass fiber product coated with the anti-hydrolysis glass fiber sizing agent according to any one of claims 1 to 6 in the field of reinforced polyamide 6 composite materials.

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