Impregnating compound for glass fiber and preparation method, product and application thereof

Abstract

The invention discloses a glass fiber impregnating compound. The glass fiber impregnating compound comprises effective components and water, the solid content of the impregnating compound is 6.9 to 18.3 percent; the effective components comprise a silane coupling agent, a film-forming agent, a nucleating agent and a compatilizer; the impregnating compound comprises the following effective components in percentage by mass based on the total mass of the impregnating compound: 0.5-1.5% of the silane coupling agent, 6-15% of the film-forming agent, 0.2-1% of the nucleating agent and 0.2-0.8% of the compatilizer, the film-forming agent is a mixture of maleic anhydride modified polypropylene emulsion with high grafting rate and olefin type polyurethane emulsion. The chopped glass fiber produced by coating the impregnating compound has excellent stiffness and bundling property, is smooth to extrude and use, and has better compatibility with polypropylene resin, and the polypropylene resin composite material reinforced by the chopped glass fiber has excellent mechanical property.

Description

Technical Field

[0001] This application relates to the field of glass fiber manufacturing technology, and in particular to a sizing agent for glass fibers, as well as a method for preparing the sizing agent, products and applications thereof. Glass fibers coated with the sizing agent are particularly suitable for the production of reinforced polypropylene resin composites. Background Technology

[0002] Polypropylene resin (PP resin) is a structurally regular crystalline polymer, a non-toxic, odorless, and lightweight thermoplastic resin with excellent chemical resistance, heat resistance, and cost-effectiveness, making it widely used in automobiles, home appliances, and medical devices. Currently, glass fiber is commonly used to enhance the mechanical properties of polypropylene resin. However, polypropylene resin is a non-polar resin, while glass fiber is a polar inorganic material; their compatibility is poor, making it difficult to obtain composite materials with high mechanical properties. Despite this, the market demand for high-performance glass fiber reinforced polypropylene composites is growing rapidly. Currently, traditional sizing agents used in glass fiber coating processes result in poor compatibility between glass fiber and PP resin, leading to limited performance improvements in the composite material.

[0003] Therefore, to meet market demand, there is an urgent need for an impregnating agent to improve the compatibility between glass fibers and polypropylene resin, thereby enhancing the mechanical properties of glass fiber reinforced polypropylene composites. Thus, the design of such glass fiber impregnating agents is crucial. Summary of the Invention

[0004] This application aims to solve the problems described above. The purpose of this application is to provide a sizing agent for glass fibers, its preparation method, products, and applications. Short-cut glass fibers coated with the sizing agent of this application exhibit excellent stiffness and bundle properties, and PP resin composites reinforced with it possess excellent mechanical properties.

[0005] According to one aspect of this application, a glass fiber impregnating agent is provided, the impregnating agent comprising an effective component and water; the solid content of the impregnating agent is 6.9% to 18.3%; the effective component comprises a silane coupling agent, a film-forming agent, a nucleating agent, and a compatibilizer; the percentage of the solid mass of each effective component of the impregnating agent to the total mass of the impregnating agent is expressed as follows:

[0006]

[0007] The film-forming agent is a mixture of maleic anhydride-modified polypropylene emulsion with a high grafting rate and olefin-type polyurethane emulsion.

[0008] Furthermore, the solid content of the wetting agent is 13.1% to 18.3%; the percentage of the solid mass of each effective component of the wetting agent to the total mass of the wetting agent is expressed as follows:

[0009]

[0010] The film-forming agent is a mixture of maleic anhydride-modified polypropylene emulsion with a high grafting rate and olefin-type polyurethane emulsion.

[0011] Furthermore, the silane coupling agent is a primary aminosilane coupling agent.

[0012] Furthermore, the silane coupling agent is one or a mixture of two of γ-aminopropyltriethoxysilane and γ-aminopropyltrimethoxysilane;

[0013] Furthermore, the maleic anhydride-modified polypropylene emulsion has a maleic anhydride grafting rate of ≥1.5% and a molecular weight of 50,000 to 150,000; the olefin-type polyurethane emulsion has a molecular weight of ≥10,000.

[0014] Furthermore, the proportion of solid mass of the maleic anhydride-modified polypropylene emulsion with a high grafting rate to the total solid mass of the film-forming agent is ≥90%.

[0015] Furthermore, the nucleating agent is one or a mixture of any of the following: unsaturated carboxylic acid polymers, unsaturated acid anhydride polymers, olefin-unsaturated carboxylic acid copolymers, and olefin-unsaturated acid anhydride copolymers.

[0016] Furthermore, the nucleating agent has a pH of 7–9.

[0017] Furthermore, the compatibilizer is polyethyleneimine.

[0018] Furthermore, the molecular weight of the polyethyleneimine is between 10,000 and 100,000.

[0019] The functions and contents of each effective component in the glass fiber impregnating agent are explained below:

[0020] The silane coupling agent used in this application is a primary aminosilane coupling agent, with one end group being methoxy or ethoxy, which forms silanol groups after hydrolysis. These silanol groups can undergo a condensation reaction with the hydroxyl groups on the glass fiber surface, thus firmly fixing the silane coupling agent to the glass fiber surface. Simultaneously, the other end group is a primary amine group, belonging to small molecule primary amines. Compared to the primary amines on compatibilizers, the primary amine groups on the silane coupling agent are more reactive and more easily react chemically with maleic anhydride-modified polypropylene emulsion, forming a bridging effect. Preferably, the primary aminosilane coupling agent is one or a mixture of any two of γ-aminopropyltriethoxysilane and γ-aminopropyltrimethoxysilane. Suitable examples of primary aminosilane coupling agents include A-1100 and A-1110 from MOMENTIVE, KBM-903 and KBE-903 from Shin-Etsu Chemical Co., Ltd., and KH-550 from Chenguang New Materials Co., Ltd. Furthermore, the amount of silane coupling agent used needs to be controlled within a suitable range. If the content of silane coupling agent is too low, the interfacial bonding force between the glass fiber and the sizing agent will be poor; while if the content is too high, it will lead to excessive cross-linking of the coupling agent itself, making it difficult to disperse the glass fiber. Therefore, in this application, the percentage of the solid mass of the silane coupling agent in the sizing agent for glass fiber is controlled to be 0.5% to 1.5% of the total mass of the sizing agent, preferably 1% to 1.5%.

[0021] Film-forming agents are the main components of the sizing agents used in this application for glass fibers. They protect glass fibers and improve their bundle properties, having a decisive impact on the continuous production and application of glass fibers. The film-forming agent in this application is a mixture of maleic anhydride-modified polypropylene emulsion with a high grafting rate and an olefin-type polyurethane emulsion. Specifically, the maleic anhydride-modified polypropylene emulsion has a maleic anhydride grafting rate ≥1.5% and a molecular weight of 50,000 to 150,000. Suitable examples of maleic anhydride-modified polypropylene emulsions include AQUACER 205RC1583 and 147RC1583 from BYK Chemicals; the olefin-type polyurethane emulsion has a molecular weight ≥10,000. Suitable examples of olefin-type polyurethane emulsions include SE-1200, SB-1200, and DA-1010 from UNITIKA. Experiments have shown that high molecular weight maleic anhydride-modified polypropylene emulsions can impart good bundleability and stiffness to chopped glass fibers. Simultaneously, a maleic anhydride grafting rate ≥1.5% provides more crosslinking points for the maleic anhydride-modified polypropylene emulsion, increasing the crosslinking density between the coupling agent and the film-forming agent, promoting the firm adhesion of the sizing agent to the glass fiber surface, and exhibiting good compatibility with PP resin, thus providing higher mechanical properties to the composite material. Olefin-type polyurethane emulsions can provide good elastic protection for glass fibers, reducing the generation of fuzz in chopped glass fibers during production and use. Furthermore, the olefin structure in the chain segments has certain similarities to that of polypropylene; therefore, introducing a small amount of olefin-type polyurethane emulsion into the sizing agent will not significantly affect the performance of the composite material. Specifically, the molecular weight of the olefin-type polyurethane emulsion is ≥10,000. Experiments have shown that the film-forming agent combination used in this application has good compatibility with PP resin.

[0022] Furthermore, the amount of film-forming agent must be controlled within a certain range. Too low a content will result in poor fiber bundle structure and reduced compatibility between the glass fiber and PP resin, leading to poorer mechanical properties of the composite material. Conversely, too high a content will result in excessively high glass fiber costs, which is not economically viable. Therefore, this application controls the percentage of the solid mass of the film-forming agent to the total mass of the sizing agent to be 6-15%, preferably 11-15%. Preferably, the solid mass of the maleic anhydride-modified polypropylene emulsion with a high grafting rate accounts for ≥90% of the total solid mass of the film-forming agent. A reasonable combination of film-forming agents can improve the bundle structure and stiffness of the glass fiber, enhance compatibility with PP resin, and impart excellent mechanical properties to the composite material while meeting economic requirements.

[0023] In this application, the nucleating agent is mainly used to promote the nucleation of PP resin. During the melt blending of glass fiber and PP resin, a small amount of nucleating agent is introduced into the wetting agent. When the nucleating agent comes into contact with the PP resin, it provides a heterogeneous surface, lowers the nucleation energy barrier, and simultaneously, the carboxyl or anhydride groups of the nucleating agent interact with the PP resin molecularly, increasing nucleation sites, accelerating the crystallization rate, refining the crystal size, and thus improving mechanical properties. The nucleating agent in this application is one or a mixture of any of the following: unsaturated carboxylic acid polymers, unsaturated anhydride polymers, olefin-unsaturated carboxylic acid copolymers, and olefin-unsaturated anhydride copolymers. Examples of suitable nucleating agents include polyacrylic acid, polymaleic anhydride, ethylene-acrylic acid copolymer, and ethylene-maleic anhydride copolymer. Suitable nucleating agents include Prime 4983-40R (olefin-unsaturated carboxylic acid copolymer) and Prime 4990R (olefin-unsaturated carboxylic acid copolymer) from Macquarie Corporation, AS-type polyacrylic acid (unsaturated carboxylic acid polymer) from Shokubai Corporation, HPMA (unsaturated anhydride polymer) from Taihe Technology, and ISOBAM-104 (olefin-unsaturated anhydride copolymer) and ISOBAM-306 (olefin-unsaturated anhydride copolymer) from Kuraray Corporation. Preferably, the pH of the nucleating agent is 7-9, which is beneficial to the stability of the wetting agent system. Experiments have shown that if the nucleating agent content is too low, the improvement in the mechanical properties of the composite material is not significant; while if the content is too high, it will cause a decrease in the mechanical properties of the composite material and reduce the compatibility between glass fiber and PP resin. Therefore, the amount of nucleating agent used in this application needs to be controlled within a certain range. Specifically, the percentage of the solid mass of the nucleating agent to the total mass of the wetting agent is controlled to be 0.2-1%, preferably 0.6-1%.

[0024] The compatibilizer in this application is mainly used to improve the compatibility between glass fiber and PP resin, specifically polyethyleneimine. During the melt blending process of glass fiber and PP resin, an appropriate amount of maleic anhydride-grafted polypropylene solid resin is generally added for further compatibilization. Under high temperature conditions, polyethyleneimine can react with the maleic anhydride-grafted polypropylene solid resin, adsorbing it onto the surface of the glass fiber, thereby improving the compatibility between the glass fiber and PP resin and enhancing the mechanical properties of the composite material. Preferably, the molecular weight of polyethyleneimine is 10,000 to 100,000. Suitable examples of polyethyleneimine include SP-200, HM-2000, and P-1050 from Catalyst Co., Ltd., PEI-M600 from Mega Chemical Co., Ltd., and UN-20325 and UN-1015W from Yuen Chemical Co., Ltd. Meanwhile, the amount of compatibilizer must be controlled within a certain range; this application controls the percentage of the solid mass of the compatibilizer to the total mass of the wetting agent to be 0.2% to 0.8%. Firstly, the compatibilizer content should not be too low, resulting in insignificant improvement in mechanical properties. Secondly, the content should not be too high, as this would increase the polarity of the entire sizing agent system and reduce the compatibility between glass fiber and PP resin. Preferably, the solid mass of the compatibilizer accounts for 0.5% to 0.8% of the total mass of the sizing agent.

[0025] In the glass fiber sizing agent of this application, the primary aminosilane coupling agent can firmly adhere to the glass fiber surface, providing excellent bonding force between the sizing agent and the glass fiber interface. Simultaneously, it can form more crosslinking points with the maleic anhydride-modified polypropylene emulsion with a high grafting rate, forming a denser crosslinking network and providing better internal strength to the sizing agent. The compatibilizer can react with and adsorb the maleic anhydride-grafted polypropylene solid resin added during melt blending onto the sizing agent surface, thereby improving the compatibility between the glass fiber and PP resin. The nucleating agent promotes PP resin nucleation, further improving the mechanical properties of the composite material. The olefin-type polyurethane emulsion imparts a certain elasticity to the sizing agent, reducing the generation of fuzz during the production and use of chopped glass fibers. Through a reasonable sizing agent formulation design, the synergistic effect of each component in the sizing agent is prominent; the chopped glass fibers coated with this sizing agent exhibit excellent stiffness and bundle properties, smooth extrusion, good compatibility with PP resin, and high mechanical properties of the enhanced PP resin composite material, meeting market and application demands.

[0026] In this application, if the active component is in liquid form, its percentage content refers to the percentage of the solid mass of the active component after drying to the total mass of the wetting agent, such as maleic anhydride modified polypropylene emulsion with a high grafting rate.

[0027] This application uses water as the dispersed phase for each component of the wetting agent. Compared with the solvent dispersed phase, water is more environmentally friendly and safer. Among them, deionized water is preferred.

[0028] The solid content of the wetting agent described in this application is 6.9% to 18.3%, preferably 13.1% to 18.3%.

[0029] According to a second aspect of this application, a method for preparing the aforementioned sizing agent for glass fibers is provided, comprising the following steps:

[0030] 1S: Pre-hydrolysis of silane coupling agent: The silane coupling agent is pre-hydrolyzed and then added to the container;

[0031] Dilution of film-forming agent: Dilute the film-forming agent with water to form a diluted film-forming agent solution;

[0032] Dilution of nucleating agent: Dilute the nucleating agent with water to form a diluted nucleating agent solution;

[0033] Dilution of compatibilizer: Dilute the compatibilizer with water to form a diluted compatibilizer solution;

[0034] 2S: Mix the diluted film-forming agent solution, nucleating agent solution, compatibilizer solution and hydrolyzed silane coupling agent solution, stir evenly, add water to the set value of the wetting agent mass, and continue stirring evenly.

[0035] In step 1S, the pre-hydrolysis of the silane coupling agent, the dilution of the film-forming agent, the dilution of the nucleating agent, and the dilution of the compatibilizer are not in any particular order. The silane coupling agent can be pre-hydrolyzed first, or the film-forming agent can be diluted first, or the nucleating agent or compatibilizer can be diluted first. At the same time, the treatment of all four components can be carried out together.

[0036] Furthermore, the silane coupling agent is hydrolyzed using 20 to 50 times its solid weight in room temperature water (10-30°C).

[0037] Furthermore, the film-forming agent is diluted with water at a ratio of 1 to 5 times the solid weight of the film-forming agent.

[0038] Furthermore, the nucleating agent is diluted with water at a ratio of 1 to 5 times the solid mass of the nucleating agent.

[0039] Furthermore, the compatibilizer is diluted with 1 to 5 times its weight in water.

[0040] According to a third aspect of this application, a chopped glass fiber product produced by coating the aforementioned glass fiber with a sizing agent is provided.

[0041] According to the fourth aspect of this application, the aforementioned glass fiber product is provided for use in the field of reinforced PP resin composite materials.

[0042] The combustible content of the glass fiber in this application is generally controlled between 0.5% and 1.5%, and the specific value needs to be adjusted according to the performance indicators that the product needs to achieve.

[0043] Compared with the prior art, the chopped glass fiber products produced by coating with the sizing agent described in this application have excellent stiffness and bundle properties, smooth extrusion, and the PP resin composite materials reinforced by them have high mechanical properties, which can meet market and application needs. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0045] Below are examples of preferred value ranges for the components included in the glass fiber impregnating agent according to this application.

[0046] Preferred Example 1

[0047] The glass fiber sizing agent according to this application comprises an effective component and water; the solid content of the sizing agent is 6.9% to 18.3%; the percentage of the solid mass of each effective component to the total mass of the sizing agent is expressed as follows:

[0048]

[0049] The film-forming agent is a mixture of maleic anhydride-modified polypropylene emulsion with a high grafting rate and olefin-type polyurethane emulsion. The maleic anhydride-modified polypropylene emulsion has a maleic anhydride grafting rate of ≥1.5%, a molecular weight of 50,000 to 150,000, and is BYK Chemical's AQUACER205RC1583, with a solid mass accounting for ≥90% of the total solid mass of the film-forming agent. The olefin-type polyurethane emulsion has a molecular weight of ≥10,000 and is UNITIKA's SE-1200.

[0050] The silane coupling agent is a primary aminosilane coupling agent, specifically MOMENTIVE's A-1100.

[0051] The nucleating agent is an olefin-unsaturated carboxylic acid copolymer with a pH of 7-9, specifically Prime4983-40R from Macquarie.

[0052] The compatibilizer is polyethyleneimine with a molecular weight of 10,000 to 100,000, specifically SP-200 from the catalyst company.

[0053] Preferred Example 2

[0054] The glass fiber sizing agent according to this application comprises an effective component and water; the solid content of the sizing agent is 6.9% to 18.3%; the percentage of the solid mass of each effective component to the total mass of the sizing agent is expressed as follows:

[0055]

[0056] The film-forming agent is a mixture of maleic anhydride-modified polypropylene emulsion with a high grafting rate and olefin-type polyurethane emulsion. The maleic anhydride-modified polypropylene emulsion has a maleic anhydride grafting rate of ≥1.5% and a molecular weight of 50,000 to 150,000. It is BYK Chemical's AQUACER205RC1583, and the solid mass accounts for ≥90% of the total solid mass of the film-forming agent. The olefin-type polyurethane emulsion has a molecular weight of ≥10,000 and is UNITIKA's SB-1200.

[0057] The silane coupling agent is a primary aminosilane coupling agent, specifically MOMENTIVE's A-1110.

[0058] The nucleating agent is a mixture of unsaturated anhydride polymers and olefin-unsaturated anhydride copolymers, specifically a mixture of HPMA from Taihe Technology and ISOBAM-104 from Kuraray Corporation.

[0059] The compatibilizer is polyethyleneimine with a molecular weight of 10,000 to 100,000, specifically PEI-M600 from Meigu Chemical Co., Ltd.

[0060] Preferred Example 3

[0061] The glass fiber sizing agent according to this application comprises an effective component and water; the solid content of the sizing agent is 13.1% to 18.3%; the percentage of the solid mass of each effective component to the total mass of the sizing agent is expressed as follows:

[0062]

[0063] The film-forming agent is a mixture of maleic anhydride-modified polypropylene emulsion with a high grafting rate and olefin-type polyurethane emulsion. The maleic anhydride-modified polypropylene emulsion has a maleic anhydride grafting rate of ≥1.5% and a molecular weight of 50,000 to 150,000, and is BYK Chemical's AQUACER205RC1583, with a solid mass accounting for ≥90% of the total solid mass of the film-forming agent. The olefin-type polyurethane emulsion has a molecular weight of ≥10,000 and is UNITIKA's DA-1010.

[0064] The silane coupling agent is a primary aminosilane coupling agent, specifically Shin-Etsu Corporation's KBM-903.

[0065] The nucleating agent is a mixture of unsaturated carboxylic acid polymers, unsaturated acid anhydride polymers, and olefin-unsaturated acid anhydride copolymers, specifically a mixture of AS-type polyacrylic acid from Catalyst Co., Ltd., HPMA from Taihe Technology Co., Ltd., and ISOBAM-306 from Kuraray Co., Ltd.

[0066] The compatibilizer is polyethyleneimine with a molecular weight of 10,000 to 100,000, specifically UN-20325 from Yuen Chemical Co., Ltd.

[0067] Preferred Example 4

[0068] The sizing agent for glass fibers according to this application comprises an effective component and water; the solid content of the sizing agent is 13.1% to 18.3%; the percentage of the solid mass of each effective component to the total mass of the sizing agent is expressed as follows:

[0069]

[0070] The film-forming agent is a mixture of maleic anhydride-modified polypropylene emulsion with a high grafting rate and olefin-type polyurethane emulsion. The maleic anhydride-modified polypropylene emulsion has a maleic anhydride grafting rate of ≥1.5% and a molecular weight of 50,000 to 150,000, and is BYK Chemical's AQUACER205RC1583, with a solid mass accounting for ≥90% of the total solid mass of the film-forming agent. The olefin-type polyurethane emulsion has a molecular weight of ≥10,000 and is UNITIKA's DA-1010.

[0071] The silane coupling agent is a primary aminosilane coupling agent, namely KH-550 from Chenguang New Materials.

[0072] The nucleating agent is a mixture of unsaturated carboxylic acid polymers, unsaturated acid anhydride polymers, olefin-unsaturated carboxylic acid copolymers, and olefin-unsaturated acid anhydride copolymers, specifically a mixture of AS-type polyacrylic acid from Catalyst Co., Ltd., HPMA from Taihe Technology Co., Ltd., Prime 4990R from Michaelman Co., Ltd., and ISOBAM-306 from Kuraray Co., Ltd.

[0073] The compatibilizer is polyethyleneimine with a molecular weight of 10,000 to 100,000, specifically P-1050 from the catalyst company.

[0074] Example

[0075] To further illustrate the beneficial effects of the selected components and their content ranges in the glass fiber impregnator of this application, the following are examples of preferred values ​​for each component included in the glass fiber impregnator of this application.

[0076] The specific formulations of some embodiments of the sizing agent for glass fiber in this application are shown in Table 1. The values ​​in Table 1 are the percentage of the solid mass of the effective component to the total mass of the sizing agent.

[0077] It should be noted that the specific types, contents, and combinations of the components selected in Table 1 do not limit the scope of protection of this application.

[0078] Table 1. Proportions of each effective component of the wetting agent in the embodiments of this application.

[0079]

[0080] Table 1 (continued) Proportions of each effective component of the wetting agent in the embodiments of this application

[0081]

[0082] In Examples 1-4, the primary aminosilane coupling agent was MOMENTIVE's A-1100;

[0083] The maleic anhydride-modified polypropylene emulsion with a high grafting rate is BYK Chemical's AQUACER205RC1583; the olefin-type polyurethane emulsion is UNITIKA's SE-1200.

[0084] The unsaturated carboxylic acid polymer is AS-type polyacrylic acid from Catalyst Company, the unsaturated acid anhydride polymer is HPMA from Taihe Technology, the olefin-unsaturated carboxylic acid copolymer is Prime 4990R from Macquarie Company, and the olefin-unsaturated acid anhydride copolymer is ISOBAM-104 from Kuraray Company.

[0085] Polyethyleneimine is UN-20325 of Yuen Chemical Co., Ltd.

[0086] In Examples 5-8, the primary aminosilane coupling agent was KBM-903 from Shin-Etsu Corporation;

[0087] The maleic anhydride-modified polypropylene emulsion with a high grafting rate is BYK Chemical's AQUACER205RC1583; the olefin-type polyurethane emulsion is UNITIKA's SB-1200.

[0088] The unsaturated carboxylic acid polymer is AS-type polyacrylic acid from Catalyst Company, the unsaturated acid anhydride polymer is HPMA from Taihe Technology, the olefin-unsaturated carboxylic acid copolymer is Prime4983-40R from Mackman Company, and the olefin-unsaturated acid anhydride copolymer is ISOBAM-104 from Kuraray Company.

[0089] Polyethyleneimine is PEI-M600 from Meigu Chemical Co., Ltd.

[0090] In Examples 9-12, the primary aminosilane coupling agent is KH-550 from Chenguang New Materials.

[0091] The maleic anhydride-modified polypropylene emulsion with a high grafting rate is BYK Chemical's AQUACER205RC1583; the olefin-type polyurethane emulsion is UNITIKA's DA-1010.

[0092] The unsaturated carboxylic acid polymer is AS-type polyacrylic acid from Catalyst Company, the unsaturated acid anhydride polymer is HPMA from Taihe Technology, the olefin-unsaturated carboxylic acid copolymer is Prime 4990R from Mackman Company, and the olefin-unsaturated acid anhydride copolymer is ISOBAM-306 from Kuraray Company.

[0093] Polyethyleneimine is SP-200 from the catalyst company.

[0094] Comparative test cases

[0095] To further demonstrate the beneficial effects of this application, two commonly used glass fiber sizing agents and sizing agents with different dosage ratios were selected as comparative examples, namely Comparative Examples 1 to 4. The formulations of Comparative Examples 1 to 4 are shown below. The dosage of the effective component is the percentage of the solid mass of the effective component to the total mass of the sizing agent.

[0096] Comparative Example 1

[0097] Primary aminosilane coupling agent: γ-aminopropyltriethoxysilane, 1.2%;

[0098] Film-forming agent: Maleic anhydride modified polypropylene emulsion (maleic anhydride grafting rate 1%), 8%;

[0099] The remainder is water.

[0100] Comparative Example 2

[0101] Primary aminosilane coupling agent: γ-aminopropyltriethoxysilane, 1%;

[0102] Film-forming agent 1: Maleic anhydride modified polypropylene emulsion (maleic anhydride grafting rate 1%), 7%;

[0103] Film-forming agent 2: Maleic anhydride modified polyethylene emulsion, 2%;

[0104] The remainder is water.

[0105] Comparative Example 3

[0106] Primary aminosilane coupling agent: γ-aminopropyltriethoxysilane, 1%;

[0107] Film-forming agent 1: Maleic anhydride modified polypropylene emulsion (maleic anhydride grafting rate ≥1.5%), 11.2%;

[0108] Film-forming agent 2: olefin-based polyurethane emulsion, 0.8%;

[0109] The remainder is water.

[0110] Comparative Example 4

[0111] Azide silane coupling agent: Union Carbide Y-9066, 1%;

[0112] Film-forming agent: maleic anhydride modified polypropylene emulsion (maleic anhydride grafting rate 1%), 4.1%;

[0113] Lubricant: 4% of a mixture of silicone oil emulsion and mineral oil;

[0114] Nucleating agent: Aliphatic dicarboxylate, 0.9%;

[0115] The remainder is water.

[0116] Test case

[0117] The prepared sizing agent (Examples 1-12 and Comparative Examples 1-4) was coated onto glass fibers with a diameter of 10 μm, and the glass fibers were then chopped into glass fiber filaments with a chopped length of 3.0 mm. A composite material was prepared by extrusion and injection molding using glass fibers, PP resin, and maleic anhydride-grafted polypropylene solid resin at a mass ratio of 30:67.3:2.7. The composite material and glass fibers were tested, and the results are shown in Table 2.

[0118] Among them, tensile strength was tested according to ISO527 standard, flexural strength according to ISO178 standard, notched impact strength according to ISO179 standard, combustible content according to GB / T9914.2-2013 standard, and glass fiber content according to GB / T2577 standard.

[0119] Table 2 Performance test results of the examples and comparative examples

[0120]

[0121] Table 2 (continued) Performance test results of examples and comparative examples

[0122]

[0123] As can be seen from the test results of the composite materials in Table 2, the glass fiber reinforced polypropylene resin composite materials coated with the sizing agent of this application (Examples 1-12) are significantly better than those of Comparative Examples 1-4 in terms of tensile strength, flexural strength and notched impact strength. This indicates that the formulations of Examples 1-12 have a better effect on improving the mechanical properties of the composite materials, and the composite material prepared in Example 11 has the highest mechanical properties.

[0124] In summary, the glass fiber sizing agent formulation and preparation process provided in this application are scientifically sound and reasonable. The chopped glass fibers coated with the sizing agent of this application exhibit excellent stiffness and bundle properties, smooth extrusion, good compatibility with PP resin, and high mechanical properties of the reinforced PP resin composite material, which can meet market and application needs.

[0125] The above-described contents can be implemented individually or in various combinations, and these variations are all within the scope of protection of this application.

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A sizing agent for glass fibers, characterized in that, The wetting agent comprises an effective component and water; the solid content of the wetting agent is 6.9%–18.3%; the effective component comprises a silane coupling agent, a film-forming agent, a nucleating agent, and a compatibilizer; the percentage of the solid mass of each effective component of the wetting agent to the total mass of the wetting agent is expressed as follows: The film-forming agent is a mixture of maleic anhydride-modified polypropylene emulsion with a high grafting rate and olefin-type polyurethane emulsion.

2. The sizing agent for glass fibers according to claim 1, characterized in that, The solid content of the wetting agent is 13.1% to 18.3%; the percentage of the solid mass of each effective component of the wetting agent to the total mass of the wetting agent is expressed as follows: The film-forming agent is a mixture of maleic anhydride-modified polypropylene emulsion with a high grafting rate and olefin-type polyurethane emulsion.

3. The sizing agent for glass fibers according to claim 1 or 2, characterized in that, The silane coupling agent is a primary aminosilane coupling agent.

4. The sizing agent for glass fibers according to claim 1 or 2, characterized in that, The maleic anhydride-modified polypropylene emulsion has a maleic anhydride grafting rate of ≥1.5% and a molecular weight of 50,000 to 150,000; the olefin-type polyurethane emulsion has a molecular weight of ≥10,000.

5. The sizing agent for glass fibers according to claim 1 or 2, characterized in that, The proportion of solids in the high-grafted maleic anhydride modified polypropylene emulsion to the total solids of the film-forming agent is ≥90%.

6. The sizing agent for glass fibers according to claim 1 or 2, characterized in that, The nucleating agent is one or a mixture of any of the following: unsaturated carboxylic acid polymers, unsaturated acid anhydride polymers, olefin-unsaturated carboxylic acid copolymers, and olefin-unsaturated acid anhydride copolymers.

7. The sizing agent for glass fibers according to claim 1 or 2, characterized in that, The compatibilizer is polyethyleneimine.

8. A method for preparing a sizing agent for glass fibers as described in any one of claims 1 to 7, characterized in that, Includes the following steps: 1S: Pre-hydrolysis of silane coupling agent: The silane coupling agent is pre-hydrolyzed and then added to the container; Dilution of film-forming agent: Dilute the film-forming agent with water to form a diluted film-forming agent solution; Dilution of nucleating agent: Dilute the nucleating agent with water to form a diluted nucleating agent solution; Dilution of compatibilizer: Dilute the compatibilizer with water to form a diluted compatibilizer solution; 2S: Mix the diluted film-forming agent solution, nucleating agent solution, compatibilizer solution and hydrolyzed silane coupling agent solution, stir evenly, add water to the set value of the wetting agent mass, and continue stirring evenly.

9. A glass fiber product produced by coating glass fiber with an impregnating agent according to any one of claims 1 to 7.

10. An application of the glass fiber product as described in claim 9 in the field of glass fiber reinforced polypropylene resin composites.

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