A sizing for glass fibers and a method of making, products and uses thereof

Abstract

The application discloses a sizing agent for glass fiber, which comprises effective components and water, and the solid content of the sizing agent is 7.61-18.3%. The solid mass of each effective component in the sizing agent accounts for 0.4-1.2% of the total mass of the sizing agent, 7-16% of the total mass of the sizing agent, 0.01-0.1% of the total mass of the sizing agent, and 0.2-1% of the total mass of the sizing agent. The silane coupling agent is a mixture of amino silane coupling agent and (methyl) propenyl silane coupling agent, and the film forming agent is a mixture of cross-linkable polyurethane emulsion and unsaturated polyester emulsion. The glass fiber short-cut original wire product coated by the sizing agent has good bunching property and fluidity, the mechanical property of the bulk molding compound product reinforced by the glass fiber short-cut original wire product is high, and the market and application demands can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of glass fiber production and manufacturing, in particular to a sizing agent for glass fiber, a preparation method, a product and an application of the sizing agent, and is especially suitable for the production of glass fiber reinforced bulk molding compound products. BACKGROUND

[0002] The bulk molding compound product is prepared by mixing unsaturated polyester resin, fillers, chopped glass fiber and various additives to form a bulk intermediate material, and then performing molding or injection molding. The bulk molding compound product has the advantages of low cost, good dimensional stability, excellent heat resistance and electrical properties, and is widely used in the fields of mechanical manufacturing, chemical equipment and construction.

[0003] At present, the sizing agent used for the production of chopped glass fiber for reinforcing bulk molding compound products usually uses cross-linked polyvinyl acetate emulsion as the main film-forming agent. This sizing agent meets the production needs of glass fiber to some extent, but the coated glass fiber has poor bundling and low compatibility with unsaturated polyester, and the interfacial bonding strength between the glass fiber and the unsaturated polyester is low, resulting in low mechanical strength of the bulk molding compound product. Therefore, in order to improve the mechanical strength of the bulk molding compound product, it is crucial to develop a glass fiber sizing agent with high compatibility with unsaturated polyester. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a sizing agent for glass fiber. The glass fiber chopped strand product coated by the sizing agent has good bundling and flowability, and the bulk molding compound product reinforced by the glass fiber has high mechanical properties, which meets the market and application requirements.

[0005] In order to achieve the above purpose, the present application realizes the following technical solutions:

[0006] According to one aspect of the present application, a sizing agent for glass fiber is provided, which comprises effective components and water; the solid content of the sizing agent is 7.61-18.3%, and the effective components comprise silane coupling agent, film-forming agent, polymerization inhibitor and pH value regulator. The solid mass percentage of each effective component of the sizing agent in the total mass of the sizing agent is as follows:

[0007]

[0008] The silane coupling agent is a mixture of amino silane coupling agent and (methyl) propenyl silane coupling agent, and the film-forming agent is a mixture of cross-linkable polyurethane emulsion and unsaturated polyester emulsion.

[0009] Further, the solid content of the infiltrant is 11.05-18.3%; the solid mass of each effective component of the infiltrant accounts for the percentage of the total mass of the infiltrant as follows:

[0010]

[0011] Further, the amino silane coupling agent is at least one of γ-aminopropyl triethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyldimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane; the (meth)acryl silane coupling agent is γ-(meth)acryloxy propyl trimethoxysilane and / or γ-(acryloxy) propyl trimethoxysilane.

[0012] Further, the mass ratio of the amino silane coupling agent to the (meth)acryl silane coupling agent is 1:2-1:1.

[0013] Further, the cross-linkable polyurethane emulsion is non-ionic, contains carbon-carbon double bonds in the polymer chain segment and has a weight average molecular weight less than 20000.

[0014] Further, the unsaturated polyester emulsion is non-ionic and has a weight average molecular weight less than 15000.

[0015] Further, the mass ratio of the cross-linkable polyurethane emulsion to the unsaturated polyester emulsion is 1:7-1:1.

[0016] Further, the polymerization inhibitor is at least one of sodium sulfate, diethyl hydroxylamine and piperidine alcohol oxide.

[0017] Further, the pH value regulator is at least one of acetic acid, oxalic acid and citric acid.

[0018] In the infiltrant for glass fibers of the present application, the amino group in the amino silane coupling agent has strong polarity and the cross-linkable polyurethane emulsion has good adhesion to glass fibers, which can improve the stiffness and bundling of the glass fibers. In the (meth)acryl silane coupling agent, the (meth)acryl group can provide cross-linking points and the unsaturated polyester emulsion has high carbon-carbon double bond content and strong reactivity, which can highly cross-link with the unsaturated polyester to improve the mechanical strength of the bulk molding compound product. The polymerization inhibitor prevents the thermal initiation of the silane coupling agent and the carbon-carbon double bond in the film forming agent during the production of the glass fibers, so as to reduce the content. The pH value regulator promotes the hydrolysis of the (meth)acryl silane coupling agent. Through the synergistic effect of each component in the infiltrant, the glass fibers have good stiffness and bundling and the bulk molding compound product reinforced by the glass fibers has high mechanical performance, which meets the market and application requirements.

[0019] The functions and contents of each effective component in the infiltrant for glass fibers are as follows:

[0020] The silane coupling agent can condense with the surface of the glass fiber and firmly fix on the surface of the glass fiber. The silane coupling agent in the application is a mixture of amino silane coupling agent and (meth)acryl silane coupling agent. The end group of the amino silane coupling agent is amino group, which has strong polarity and can form strong intermolecular force with the film forming agent to improve the bunching property of the glass fiber. The end group of the (meth)acryl silane coupling agent is (meth)acryl group, which has reactivity and can chemically react with the film forming agent and the unsaturated polyester resin to improve the mechanical strength of the bulk molding compound. The amino silane coupling agent in the application can be at least one of γ-aminopropyl triethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyl dimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane. The (meth)acryl silane coupling agent in the application can be γ-(meth)acryloxy propyl trimethoxysilane or / and γ-(acryloxy) propyl trimethoxysilane. The amount of the silane coupling agent must be controlled within a certain range. If the content of the silane coupling agent is too low, the interfacial bonding force between the glass fiber and the impregnant is poor; if the content is too high, the glass fiber is difficult to disperse. Therefore, the solid mass percentage of the silane coupling agent in the total mass of the impregnant is controlled to be 0.4-1.2%, preferably 0.6-1.2%.

[0021] In the application, the reasonable control of the amount of the two kinds of silane coupling agents can reasonably adjust and improve the bunching property and stiffness of the glass fiber and the mechanical properties of the bulk molding compound. The inventors have found that when the proportion of the amino silane coupling agent is too low, the bunching property and stiffness of the glass fiber become poor, and when the proportion of the (meth)acryl silane coupling agent is too low, the mechanical strength of the bulk molding compound becomes low. Therefore, in the application, the mass ratio of the amino silane coupling agent to the (meth)acryl silane coupling agent is controlled to be 1:2-1:1; for example, the mass ratio of the amino silane coupling agent to the (meth)acryl silane coupling agent is 1:2, 1:1.7, 1:1.5, 1:1.2 or 1:1.

[0022] The film forming agent is the main component of the sizing agent for glass fibers, which has the functions of protecting the glass fibers and improving the bunching and stiffness of the glass fibers, and has a decisive influence on the continuous production and application of the glass fibers. The film forming agent of the present application is a mixture of cross-linkable polyurethane emulsion and unsaturated polyester emulsion. The cross-linkable polyurethane emulsion has strong polarity, which can improve the bunching and stiffness of the glass fibers, and has reactivity at the same time. The unsaturated polyester emulsion has high content of carbon-carbon double bond and strong reactivity, which can highly cross-link with the (meth) acryl silane coupling agent and unsaturated resin, and improve the mechanical strength of the bulk molding compound product. The cross-linkable polyurethane emulsion of the present application can be non-ionic, and the weight average molecular weight is less than 20000, that is, the polyurethane synthesis formula contains hydroxyethyl acrylate or hydroxyethyl methacrylate monomer. The unsaturated polyester emulsion of the present application can be non-ionic, and the weight average molecular weight is less than 15000. At the same time, the amount of the film forming agent must be controlled in a certain range: if the content of the film forming agent is too low, the bunching of the glass fibers is too poor; if the content is too high, the glass fibers cannot be fully soaked in the unsaturated polyester, and the soaking effect is poor. Therefore, the solid content of the film forming agent in the sizing agent is controlled to be 7-16%, and preferably 10-16%.

[0023] In the present application, the reasonable control of the amount of the two film forming agents can reasonably adjust and improve the bunching, stiffness of the glass fibers and the mechanical properties of the bulk molding compound product. The inventors have found that when the proportion of the cross-linkable polyurethane emulsion is too low, the bunching and stiffness of the glass fibers are poor; and when the proportion of the unsaturated polyester emulsion is too low, the mechanical strength of the bulk molding compound product is low. Therefore, the mass ratio of the cross-linkable polyurethane emulsion to the unsaturated polyester emulsion is controlled to be 1:7-1:1 in the present application. For example, the mass ratio of the cross-linkable polyurethane emulsion to the unsaturated polyester emulsion is 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, 1:1.

[0024] In the present application, the role of the polymerization inhibitor is to prevent the carbon-carbon double bond in the (meth) acryl silane coupling agent, the cross-linkable polyurethane emulsion and the unsaturated polyester emulsion from being thermally initiated during the high temperature drying of the raw yarn. Thermal initiation can cause a sharp decrease in the content of the carbon-carbon double bond in the sizing agent, which ultimately leads to a decrease in the cross-linking density of the sizing agent and the unsaturated polyester, and a decrease in the mechanical properties of the bulk molding compound product. The amount of the polymerization inhibitor must also be controlled in a certain range: if the content of the polymerization inhibitor is too low, the mechanical properties of the bulk molding compound product are low; if the content is too high, it will reduce the initiation efficiency of the initiator during the molding or injection molding of the bulk intermediate material, and also cause the mechanical properties of the bulk molding compound product to be low. Therefore, the solid content of the polymerization inhibitor in the sizing agent is controlled to be 0.01-0.1%, and preferably 0.05-0.1%.

[0025] The pH regulator is used in the present application mainly to promote the hydrolysis of the (meth) acryl silane coupling agent in water. The pH regulator of the present application is preferably an acid, such as at least one of acetic acid, oxalic acid, and citric acid. Exemplarily, the pH regulator is acetic acid. Acetic acid, oxalic acid, and citric acid can all accelerate the hydrolysis of the (meth) acryl silane coupling agent in water. Meanwhile, the amount of the pH regulator must also be controlled within a certain range: too little pH regulator content will make the (meth) acryl silane coupling agent hydrolyze for too long a time; too much content will result in too strong acidity of the system, reducing the stability of the sizing agent. Therefore, the present application controls the solid mass percentage of the pH regulator in the total mass of the sizing agent to be 0.2-1%; preferably 0.4-1%.

[0026] Water is used in the present application as the dispersion phase of the components of the sizing agent, and is more environmentally friendly and safe than a solvent dispersion phase. The water is preferably deionized water.

[0027] The solid content of the sizing agent described in the present application is 7.61-18.3%, preferably 11.05-18.3%.

[0028] According to a second aspect of the present application, a method for preparing the aforementioned sizing agent for glass fibers is provided, comprising the following steps:

[0029] S1: adding 20-40% of the total mass of the sizing agent into a container, and sequentially adding a pH regulator and a silane coupling agent, and stirring until uniform;

[0030] S2: adding a film-forming agent diluted with water into the container of step S1;

[0031] S3: adding a polymerization inhibitor diluted with water into the container of step S2;

[0032] S4: adding water to the container of step S3 to reach a set value of the mass of the sizing agent, and stirring until uniform.

[0033] Further, the film-forming agent in step S2 is diluted with 1-5 times the solid mass of water.

[0034] Further, the polymerization inhibitor in step S3 is diluted with 1-5 times the solid mass of water.

[0035] The order of step S2 and step S3 is not fixed, and can be adjusted relative to each other, i.e. the film-forming agent diluted with water can be added first into the container of step S1, followed by the polymerization inhibitor diluted with water; or the polymerization inhibitor diluted with water can be added first into the container of step S1, followed by the film-forming agent diluted with water; or the film-forming agent diluted with water and the polymerization inhibitor diluted with water can be added simultaneously into the container of step S1.

[0036] According to a third aspect of the present application, there is provided a glass fiber product produced by coating the aforementioned sizing agent on the glass fiber.

[0037] According to a fourth aspect of the present application, there is provided an application of the aforementioned glass fiber product in the field of reinforced bulk molding compound products.

[0038] The combustible content of the glass fiber of the present application is generally controlled at 1.0-2.5%, which needs to be adjusted according to the performance index required by the product.

[0039] Compared with the prior art, the glass fiber chopped strand product produced by coating the sizing agent of the present application has good bundling and flowability, and the bulk molding compound product reinforced by the same has high mechanical properties, meeting the market and application requirements. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the present application will be described clearly and completely below in combination with specific embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other in any manner without conflict.

[0041] The beneficial effects of selecting the aforementioned range of the content of each component in the sizing agent for glass fiber of the present application will be illustrated by specific experimental data.

[0042] The following are examples of the preferred value range of each component included in the sizing agent for glass fiber according to the present application.

[0043] Preferred Example One

[0044] The sizing agent for glass fiber according to the present application comprises effective components and water; the solid content of the sizing agent is 7.61-18.3%; the mass percentage of each effective component in the total mass of the sizing agent is shown as follows:

[0045]

[0046]

[0047] The silane coupling agent is a mixture of amino silane coupling agent and (methyl)propenyl silane coupling agent, the film forming agent is a mixture of cross-linkable polyurethane emulsion and unsaturated polyester emulsion, and the polymerization inhibitor is at least one of sodium sulfate, diethyl hydroxylamine and piperidine alcohol oxide.

[0048] Preferred Example Two

[0049] The sizing agent for glass fibers according to the present application comprises effective components and water; the solid content of the sizing agent is 7.61-18.3%; the percentage of the solid mass of each effective component in the total mass of the sizing agent is shown as follows:

[0050]

[0051] The silane coupling agent is a mixture of amino silane coupling agent and (methyl)propenyl silane coupling agent, the film forming agent is a mixture of cross-linkable polyurethane emulsion and unsaturated polyester emulsion, the amino silane coupling agent is at least one of γ-aminopropyl triethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyl dimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane, and the (methyl)propenyl silane coupling agent is γ-(methacryloyloxy)propyl trimethoxysilane and / or γ-(acryloyloxy)propyl trimethoxysilane.

[0052] Preferred Example Three

[0053] The sizing agent for glass fibers according to the present application comprises effective components and water; the solid content of the sizing agent is 7.61-18.3%; the percentage of the solid mass of each effective component in the total mass of the sizing agent is shown as follows:

[0054]

[0055] The silane coupling agent is a mixture of amino silane coupling agent and (methyl)propenyl silane coupling agent, the film forming agent is a mixture of cross-linkable polyurethane emulsion and unsaturated polyester emulsion; the cross-linkable polyurethane emulsion is non-ionic, contains carbon-carbon double bond in the polymer chain segment, and has a weight average molecular weight less than 20000; the unsaturated polyester emulsion is non-ionic, and has a weight average molecular weight less than 15000.

[0056] Preferred Example Four

[0057] The sizing agent for glass fibers according to the present application comprises effective components and water; the solid content of the sizing agent is 7.61-18.3%; the percentage of the solid mass of each effective component in the total mass of the sizing agent is shown as follows:

[0058]

[0059] The silane coupling agent is a mixture of amino silane coupling agent and (methyl)propenyl silane coupling agent, the film forming agent is a mixture of cross-linkable polyurethane emulsion and unsaturated polyester emulsion, the mass ratio of the amino silane coupling agent to the methyl propenyl silane coupling agent is 1:2-1:1, and the mass ratio of the cross-linkable polyurethane emulsion to the unsaturated polyester emulsion is 1:7-1:1.

[0060] Preferred Example Five

[0061] The sizing agent for glass fibers according to the present application comprises effective components and water; the solid content of the sizing agent is 7.61-18.3%; the percentage of the solid mass of each effective component in the total mass of the sizing agent is shown as follows:

[0062]

[0063] wherein the silane coupling agent is a mixture of amino silane coupling agent and (methyl)acryl silane coupling agent, the film forming agent is a mixture of cross-linkable polyurethane emulsion and unsaturated polyester emulsion, and the mass ratio of the amino silane coupling agent to the (methyl)acryl silane coupling agent is 1:2-1:1; the amino silane coupling agent is at least one of γ-aminopropyl triethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyldimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane; and the (methyl)acryl silane coupling agent is γ-(methacryloxy)propyl trimethoxysilane and / or γ-(acryloxy)propyl trimethoxysilane.

[0064] Preferred Example Six

[0065] The sizing agent for glass fibers according to the present application comprises effective components and water; the solid content of the sizing agent is 7.61-18.3%; the percentage of the solid mass of each effective component in the total mass of the sizing agent is shown as follows:

[0066]

[0067] wherein the silane coupling agent is a mixture of amino silane coupling agent and (methyl)acryl silane coupling agent, the film forming agent is a mixture of cross-linkable polyurethane emulsion and unsaturated polyester emulsion, and the mass ratio of the amino silane coupling agent to the (methyl)acryl silane coupling agent is 1:2-1:1; the amino silane coupling agent is at least one of γ-aminopropyl triethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyldimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane; and the (methyl)acryl silane coupling agent is γ-(methacryloxy)propyl trimethoxysilane and / or γ-(acryloxy)propyl trimethoxysilane.

[0068] Preferred Example Seven

[0069] The sizing agent for glass fibers according to the present application comprises effective components and water; the solid content of the sizing agent is 7.61-18.3%; the percentage of the solid mass of each effective component in the total mass of the sizing agent is shown as follows:

[0070]

[0071] The silane coupling agent is a mixture of an amino silane coupling agent and a (meth)acryl silane coupling agent, the mass ratio of the amino silane coupling agent to the (meth)acryl silane coupling agent is 1:2 to 1:1; the amino silane coupling agent is at least one of γ-aminopropyl triethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyldimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane; the (meth)acryl silane coupling agent is γ-(methacryloxy)propyl trimethoxysilane and / or γ-(acryloxy)propyl trimethoxysilane; the cross-linkable polyurethane emulsion and the unsaturated polyester emulsion are mixed in a mass ratio of 1:7 to 1:1; the cross-linkable polyurethane emulsion is non-ionic, contains carbon-carbon double bonds in the polymer chain segment, and has a weight average molecular weight less than 20000; the unsaturated polyester emulsion is non-ionic, and has a weight average molecular weight less than 15000; and the polymerization inhibitor is at least one of sodium sulfate, diethyl hydroxylamine and piperidine alcohol oxide.

[0072] Preferred Example Eight

[0073] The glass fiber sizing agent according to the present application comprises effective components and water; the solid content of the sizing agent is 11.05-18.3%; the percentage of the solid mass of each effective component in the total mass of the sizing agent is shown as follows:

[0074]

[0075] The silane coupling agent is a mixture of an amino silane coupling agent and a (meth)acryl silane coupling agent, the mass ratio of the amino silane coupling agent to the (meth)acryl silane coupling agent is 1:2 to 1:1; the amino silane coupling agent is at least one of γ-aminopropyl triethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyldimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane; the (meth)acryl silane coupling agent is γ-(methacryloxy)propyl trimethoxysilane and / or γ-(acryloxy)propyl trimethoxysilane; the cross-linkable polyurethane emulsion and the unsaturated polyester emulsion are mixed in a mass ratio of 1:7 to 1:1; the cross-linkable polyurethane emulsion is non-ionic, contains carbon-carbon double bonds in the polymer chain segment, and has a weight average molecular weight less than 20000; the unsaturated polyester emulsion is non-ionic, and has a weight average molecular weight less than 15000; and the polymerization inhibitor is at least one of sodium sulfate, diethyl hydroxylamine and piperidine alcohol oxide.

[0076] Preferred Example Nine

[0077] The glass fiber sizing agent according to the present application comprises effective components and water; the solid content of the sizing agent is 11.05-18.3%; the percentage of the solid mass of each effective component in the total mass of the sizing agent is shown as follows:

[0078]

[0079] The silane coupling agent is a mixture of an amino silane coupling agent and a (meth)acryl silane coupling agent, the film forming agent is a mixture of a cross-linkable polyurethane emulsion and an unsaturated polyester emulsion, the amino silane coupling agent is at least one of γ-aminopropyl triethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyldimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane, and the (meth)acryl silane coupling agent is γ-(methacryloxy)propyl trimethoxysilane and / or γ-(acryloxy)propyl trimethoxysilane.

[0080] Preferred Example Ten

[0081] The glass fiber sizing agent according to the present application comprises effective components and water; the solid content of the sizing agent is 11.05-18.3%; the percentage of the solid mass of each effective component in the total mass of the sizing agent is shown as follows:

[0082]

[0083] The silane coupling agent is a mixture of an amino silane coupling agent and a (meth)acryl silane coupling agent, the film forming agent is a mixture of a cross-linkable polyurethane emulsion and an unsaturated polyester emulsion, the amino silane coupling agent is at least one of γ-aminopropyl triethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyldimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane, and the (meth)acryl silane coupling agent is γ-(methacryloxy)propyl trimethoxysilane and / or γ-(acryloxy)propyl trimethoxysilane.

[0084] Preferred Example Eleven

[0085] The glass fiber sizing agent according to the present application comprises effective components and water; the solid content of the sizing agent is 11.05-18.3%; the percentage of the solid mass of each effective component in the total mass of the sizing agent is shown as follows:

[0086]

[0087] The silane coupling agent is a mixture of amino silane coupling agent and (methyl) acryl silane coupling agent, the film forming agent is a mixture of cross-linkable polyurethane emulsion and unsaturated polyester emulsion, the mass ratio of the amino silane coupling agent to the (methyl) acryl silane coupling agent is 1:2-1:1; the amino silane coupling agent is at least one of γ-aminopropyl triethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyldimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane; the (methyl) acryl silane coupling agent is γ-(methacryloxy) propyl trimethoxysilane and / or γ-(acryloxy) propyl trimethoxysilane; the mass ratio of the cross-linkable polyurethane emulsion to the unsaturated polyester emulsion is 1:7-1:1; the cross-linkable polyurethane emulsion is non-ionic and contains carbon-carbon double bonds in the polymer chain segment, and the weight average molecular weight is less than 20000; and the unsaturated polyester emulsion is non-ionic and the weight average molecular weight is less than 15000.

[0088] Preferable Example Twelve

[0089] The glass fiber sizing agent according to the present application comprises effective components and water; the solid content of the sizing agent is 11.05-18.3%; and the percentage of the solid mass of each effective component in the total mass of the sizing agent is shown as follows:

[0090]

[0091] The silane coupling agent is a mixture of amino silane coupling agent and (methyl) acryl silane coupling agent, the film forming agent is a mixture of cross-linkable polyurethane emulsion and unsaturated polyester emulsion, the mass ratio of the amino silane coupling agent to the (methyl) acryl silane coupling agent is 1:2-1:1; the amino silane coupling agent is at least one of γ-aminopropyl triethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyldimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane; the (methyl) acryl silane coupling agent is γ-(methacryloxy) propyl trimethoxysilane and / or γ-(acryloxy) propyl trimethoxysilane; the mass ratio of the cross-linkable polyurethane emulsion to the unsaturated polyester emulsion is 1:7-1:1; the cross-linkable polyurethane emulsion is non-ionic and contains carbon-carbon double bonds in the polymer chain segment, and the weight average molecular weight is less than 20000; and the unsaturated polyester emulsion is non-ionic and the weight average molecular weight is less than 15000.

[0092] S1: adding water accounting for 20%-40% of the total mass of the sizing agent into a container, sequentially adding a pH value regulator and a silane coupling agent, and stirring uniformly;

[0093] S2: adding the film forming agent diluted with water accounting for 1-5 times the solid mass of the film forming agent into the container in step S1;

[0094] S3: adding the polymerization inhibitor diluted with water accounting for 1-5 times the solid mass of the polymerization inhibitor into the container in step S2;

[0095] S4: adding water to the container in step S3 to reach the set value of the mass of the sizing agent, and fully stirring for 10-30 minutes to obtain the product.

[0096] The specific formulations of some embodiments of the glass fiber sizing agent according to the present application are shown in Table 1, and the values in Table 1 are the percentages of the solid mass of the effective components in the total mass of the sizing agent.

[0097] It should be noted that the specific types and amounts of the components selected in Table 1 and the combinations thereof do not limit the scope of protection of the present application.

[0098] Table 1: Proportions of the effective components of the sizing agent of the examples

[0099]

[0100]

[0101] Table 1 (continued)

[0102]

[0103] In Examples 1 to 12 of the present application, the cross-linkable polyurethane emulsion is non-ionic, contains carbon-carbon double bonds in the polymer chain segment, and has a weight average molecular weight of less than 20,000; the unsaturated polyester emulsion is non-ionic and has a weight average molecular weight of less than 15,000.

[0104] In order to further illustrate the beneficial effects of the present application, two commonly used glass fiber sizing agents were selected as Comparative Examples 1 and 2. The formulations of Comparative Examples 1 and 2 are shown below, wherein the amounts of the effective components are percentages of the solid mass of the effective components with respect to the total mass of the sizing agent.

[0105] Comparative Example 1

[0106] Silane coupling agent 1: (meth)acryl silane coupling agent 0.5%;

[0107] Silane coupling agent 2: urea-based silane coupling agent 0.1%;

[0108] Film-forming agent 1: polyurethane emulsion 8%;

[0109] Film-forming agent 2: epoxy resin emulsion 7%;

[0110] pH adjuster: acetic acid 0.3%;

[0111] Water: 84.1%.

[0112] Comparative Example 2

[0113] Silane coupling agent: amino silane coupling agent 1%;

[0114] Film-forming agent 1: polyvinyl acetate emulsion 3.3%;

[0115] Film-forming agent 2: polyurethane emulsion 3.3%;

[0116] Film-forming agent 3: epoxy resin emulsion 3.3%;

[0117] pH adjuster: citric acid 0.3%;

[0118] Water: 88.8%.

[0119] The prepared sizing agent (Examples 1-12 and Comparative Examples 1-2) was coated on glass fibers with a fiber diameter of 13 μm, and the drying process was carried out using hot air drying for 12 hours. The chopped length of the chopped glass fiber strands was 6 mm. The glass fibers, unsaturated resin, low shrinkage agent, filler, internal release agent, curing agent, and carbon black were mixed in a ratio of 18:15.93:10.6:54:0.33:0.27:0.87 to prepare a bulk intermediate material, which was molded into a bulk molding compound product. The bulk molding compound product and the glass fibers were tested, and the test results are shown in Table 2.

[0120] Table 2. Test results of the properties of the examples and comparative examples

[0121]

[0122]

[0123] Table 2 (continued)

[0124]

[0125] As can be seen from the test results of the bulk molding compound product in Table 2, the mechanical properties of the bulk molding compound product reinforced with the glass fibers coated with the sizing agent (Examples 1-12) of the present application were significantly improved compared to the mechanical properties of the sizing agent of Comparative Examples 1-2. In addition, the mechanical properties of the bulk molding compound product prepared in Example 8 were the highest among the examples. Furthermore, the inventors compared the sizing agent of the present application (Examples 1-12) with the sizing agent of other comparative examples, and the mechanical properties of the sizing agent of the other comparative examples were significantly worse than the mechanical properties of the sizing agent of Examples 1-12. The sizing agent of the other comparative examples was not a mixture of an amino silane coupling agent and a (meth)acryl silane coupling agent, and the film-forming agent was not a mixture of a cross-linkable polyurethane emulsion and an unsaturated polyester emulsion.

[0126] In summary, the sizing agent formulation and preparation process for glass fibers provided in the present application are scientific and reasonable. The glass fiber chopped strand product produced by coating the sizing agent of the present application has good bundling and flow properties, and the bulk molding compound product reinforced with the glass fiber chopped strand product has high mechanical properties, which meets the market and application requirements.

[0127] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalent ones, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A sizing for glass fibers, characterized in that, The infiltration agent is effective components and water, the effective components are silane coupling agent, film forming agent, polymerization inhibitor and pH regulator, the percentage of the solid mass of each effective component of the infiltration agent in the total mass of the infiltration agent is as follows: Silane coupling agent 0.4-1.2%; Film forming agent 7-16%; Polymerization inhibitor 0.05-0.1%; pH regulator 0.2-1%; The silane coupling agent is a mixture of amino silane coupling agent and at least one of γ-(methacryloxy) propyl trimethoxysilane and γ-(acryloxy) propyl trimethoxysilane, the film forming agent is a mixture of cross-linkable polyurethane emulsion and unsaturated polyester emulsion containing carbon-carbon double bond; The mass ratio of the cross-linkable polyurethane emulsion to the unsaturated polyester emulsion is 1:6-1:2; The polymerization inhibitor is at least two of sodium sulfate, diethyl hydroxylamine and piperidinol oxide; The cross-linkable polyurethane emulsion is non-ionic, containing carbon-carbon double bond in the polymer chain segment, and the weight average molecular weight is less than 20000; The mass ratio of the amino silane coupling agent to at least one of γ-(methacryloxy) propyl trimethoxysilane and γ-(acryloxy) propyl trimethoxysilane is 1:2-1:

1.

2. The sizing agent according to claim 1, characterized in that, The percentage of the solid mass of each effective component of the infiltration agent in the total mass of the infiltration agent is as follows: Silane coupling agent 0.6-1.2%; Film forming agent 10-16%; Polymerization inhibitor 0.05-0.1%; pH regulator 0.4-1%.

3. The sizing agent according to claim 1, characterized in that, The amino silane coupling agent is at least one of γ-aminopropyl triethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyl dimethoxysilane and N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane.

4. The sizing agent of claim 1, wherein The unsaturated polyester emulsion is non-ionic, and the weight average molecular weight is less than 15000.

5. A method of preparing the sizing agent for glass fibers according to any one of claims 1 to 4, characterized by, The method comprises the following steps: S1: adding water accounting for 20%-40% of the total mass of the infiltration agent in a container, sequentially adding pH regulator and silane coupling agent, and stirring uniformly; S2: adding film forming agent diluted with water in the container of step S1; S3: adding polymerization inhibitor diluted with water in the container of step S2; S4: adding water to the container of step S3 to the set value of the mass of the infiltration agent, stirring uniformly, and obtaining the infiltration agent.

6. A glass fiber product coated by the infiltration agent for glass fiber according to any one of claims 1-4.

7. Use of the glass fiber product according to claim 6 in the field of glass fiber reinforced bulk molding compound.

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