Basalt fiber reinforced thermoplastic prepreg tape and preparation method thereof

Abstract

The invention relates to the technical field of fiber reinforced polymer composite materials, in particular to a basalt fiber reinforced thermoplastic prepreg tape and a preparation method thereof.The preparation method comprises the steps that plasma treatment is conducted on basalt fibers to obtain surface modified basalt fibers; coating the surface modified basalt fibers with an impregnating compound to obtain impregnated modified basalt fibers; impregnating thermoplastic resin into the basalt fibers subjected to infiltration modification; wherein the impregnating compound is prepared from the following raw materials: polyolefin wax, a coupling agent and an emulsifier. According to the preparation method, the basalt fiber is subjected to surface modification and infiltration modification, so that the bonding strength of the modified basalt fiber and the thermoplastic resin is improved, the mechanical property of the material is improved, the infiltration uniformity is improved, the impregnation difficulty is reduced, and the problem of yellow spots is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of fiber-reinforced polymer composite materials, and in particular to a basalt fiber-reinforced thermoplastic prepreg tape and a preparation method thereof. Background Art

[0002] Fiber-reinforced thermoplastic prepreg tapes have the advantages of lightweight, high strength and high modulus, easy processing, and recyclability, and are widely used in automotive structural parts, pipelines and other fields. The fiber-reinforced thermoplastic prepreg tapes provided by related technologies usually use glass fiber or carbon fiber as reinforcement, while basalt fiber has higher strength and modulus, and has better temperature resistance and dielectric properties. The use of basalt fiber to prepare thermoplastic prepreg tapes has a wider application prospect.

[0003] However, since thermoplastic resins usually have a high viscosity, it is difficult to impregnate continuous fibers, which can easily lead to uneven impregnation and yellow spot problems. In addition, the compatibility of thermoplastic resins and basalt fibers is poor, and the bonding strength is not high, which causes the mechanical properties of the composite materials at the back end to be reduced to varying degrees. Summary of the invention

[0004] The object of the present invention is to provide a basalt fiber reinforced thermoplastic prepreg and a preparation method thereof. The preparation method is beneficial to improving the bonding strength between the modified basalt fiber and the thermoplastic resin, improving the mechanical properties of the material, improving the uniformity of impregnation, reducing the difficulty of impregnation, and reducing the problem of yellow spots by surface modification and impregnation modification of the basalt fiber.

[0005] The present invention is achieved in that:

[0006] In a first aspect, the present invention provides a method for preparing a basalt fiber reinforced thermoplastic prepreg tape, comprising:

[0007] Plasma treatment is performed on basalt fibers to obtain surface-modified basalt fibers;

[0008] Applying a sizing agent to the surface-modified basalt fiber to obtain a sizing-modified basalt fiber;

[0009] Thermoplastic resin is impregnated into the impregnated modified basalt fiber; wherein,

[0010] The raw materials for preparing the wetting agent include: polyolefin wax, coupling agent and emulsifier.

[0011] In an optional embodiment, the wetting agent includes, by mass percentage, 15-25% of polyolefin wax, 1-10% of coupling agent, 1-8% of emulsifier, and the balance is water.

[0012] In an alternative embodiment, the polyolefin wax includes at least one of polyethylene wax and polypropylene wax.

[0013] In an alternative embodiment, the coupling agent comprises a silane coupling agent.

[0014] In an alternative embodiment, the emulsifier comprises at least one of an alkyl sulfate and an alkyl benzene sulfonate.

[0015] In an optional embodiment, the method further includes hydrolyzing the coupling agent in the impregnating agent. The method for hydrolyzing the coupling agent includes: adding the coupling agent to water, stirring simultaneously, and controlling the pH value to 3-5.

[0016] In an optional embodiment, the gas for plasma treatment includes at least one of oxygen, nitrogen and argon; the gas pressure for plasma treatment is 0.2-0.6MPa; the temperature for plasma treatment is 50-100°C; and the power for plasma treatment is 100-1000W.

[0017] In an optional embodiment, the method of applying the sizing agent to the surface-modified basalt fiber comprises: applying the sizing agent to the surface-modified basalt fiber using a rotating oiling roller, wherein the rotation speed of the oiling roller is 50-90 r / min; and,

[0018] After the sizing agent is applied to the surface-modified basalt fiber, it is dried at a temperature of 180-250°C.

[0019] In an optional embodiment, the method for preparing the basalt fiber reinforced thermoplastic prepreg tape further comprises: spreading the impregnated and modified basalt fibers and heat treating them at a temperature of 70-150°C.

[0020] In a second aspect, the present invention provides a basalt fiber reinforced thermoplastic prepreg tape, which is prepared by the preparation method of the basalt fiber reinforced thermoplastic prepreg tape of any one of the aforementioned embodiments.

[0021] The beneficial effects of the preparation method of the basalt fiber reinforced thermoplastic prepreg tape of the present invention include: 1. By plasma treating the basalt fiber to improve the roughness of the basalt fiber surface, it is beneficial to improve the adhesion of the subsequent sizing agent and to improve the bonding force between the thermoplastic resin and the modified basalt fiber; 2. The polyolefin wax and the emulsifier in the sizing agent form a polyolefin wax emulsion, which can enhance the compatibility with the thermoplastic resin. The sizing agent containing the polyolefin wax and the emulsifier is applied to the surface of the plasma-modified basalt fiber, which can enhance the compatibility of the modified basalt fiber with the thermoplastic resin, thereby improving the fluidity of the thermoplastic resin-impregnated modified basalt fiber. , which is beneficial to improve the uniformity of impregnation, reduce the difficulty of impregnation, and reduce the problem of yellow spots; the coupling agent can improve the reactivity or compatibility of organic matter, and the coupling agent is between the inorganic and organic interfaces, which can form a bonding layer of organic matrix (polyolefin wax emulsion)-silane coupling agent-inorganic matrix (basalt fiber), improve the bonding strength between basalt fiber and impregnating agent, so as to increase the loading amount of impregnating agent on the surface of basalt fiber. On the one hand, the sufficient loaded polyolefin wax emulsion is used to improve the fluidity of thermoplastic resin impregnated with basalt fiber, and on the other hand, the coupling agent can also be used to improve the bonding strength between organic body (thermoplastic resin) and inorganic body (basalt fiber), thereby improving the mechanical properties of the material. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0023] The present invention provides a basalt fiber reinforced thermoplastic prepreg tape, and the preparation method thereof comprises: performing plasma treatment on basalt fibers to obtain surface-modified basalt fibers;

[0024] Applying a sizing agent to the surface-modified basalt fiber to obtain a sizing-modified basalt fiber;

[0025] Thermoplastic resin is impregnated into the impregnated modified basalt fiber; wherein,

[0026] The raw materials for preparing the wetting agent include: polyolefin wax, coupling agent and emulsifier.

[0027] The preparation method of the present invention can fully improve the bonding strength between basalt fiber and thermoplastic resin; wherein, 1. by plasma treatment of basalt fiber, the roughness of the surface of basalt fiber is improved, which is beneficial to improve the adhesion of subsequent sizing agent and the bonding strength between thermoplastic resin and modified basalt fiber; 2. polyolefin wax and emulsifier in the sizing agent form polyolefin wax emulsion, which can enhance the compatibility with thermoplastic resin, and the sizing agent containing polyolefin wax and emulsifier is applied to the surface of plasma-modified basalt fiber, which can enhance the compatibility between modified basalt fiber and thermoplastic resin, thereby improving the flow of thermoplastic resin impregnated modified basalt fiber. The coupling agent can improve the reactivity or compatibility of organic matter, and the coupling agent is between the inorganic and organic interfaces, which can form a bonding layer of organic matrix (polyolefin wax emulsion)-silane coupling agent-inorganic matrix (basalt fiber), improve the bonding strength between basalt fiber and the wetting agent, so as to increase the loading amount of the wetting agent on the surface of basalt fiber. On the one hand, the polyolefin wax emulsion with sufficient loading can be used to improve the fluidity of the thermoplastic resin impregnated with basalt fiber, and on the other hand, the coupling agent can also be used to improve the bonding strength between the organic body (thermoplastic resin) and the inorganic body (basalt fiber), thereby improving the mechanical properties of the material.

[0028] It should be noted that the polyolefin wax emulsion formed by polyolefin wax and emulsifier improves the compatibility of thermoplastic resin impregnated basalt fiber, improves fluidity, and can also reduce the specificity between resin and basalt fiber, so that a variety of thermoplastic resins can be used to impregnate basalt fiber, such as polyethylene, polypropylene, nylon, polyetheretherketone, etc.

[0029] Optionally, the sizing agent includes, by mass percentage, 15-25% polyolefin wax (e.g., 15%, 17%, 20%, 22%, 25%, etc.), 1-10% coupling agent (e.g., 1%, 3%, 5%, 8%, 10%, etc.), 1-8% emulsifier (e.g., 1%, 3%, 5%, 8%, etc.), and the balance is water. Among them, polyolefin wax can enhance compatibility with thermoplastic resin and improve fluidity; excessive dosage (greater than 25%) will reduce the viscosity of the sizing agent, thereby affecting the coating effect, for example, it is difficult to coat evenly, resulting in uneven bonding strength between basalt fiber and thermoplastic resin, high bonding strength in some positions, and low bonding strength in some positions; too low dosage (less than 15%) will not play a reinforcing role.

[0030] It should be understood that in other embodiments, anti-ultraviolet agents, antistatic agents, etc. may be added to the sizing agent as needed, which is not specifically limited here.

[0031] Optionally, the polyolefin wax includes at least one of polyethylene wax and polypropylene wax.

[0032] Optionally, the coupling agent includes a silane coupling agent. The silane alkoxy group in the silane coupling agent is reactive to inorganic substances, while the organic functional group is reactive or compatible to organic substances. Therefore, the silane coupling agent can be located between the inorganic and organic interfaces, and can form a bonding layer of an organic matrix-silane coupling agent-inorganic matrix, thereby improving the bonding strength between the basalt fiber and the sizing agent. On the one hand, the fluidity of the thermoplastic resin impregnated with the basalt fiber is improved by using a sufficiently loaded polyolefin wax emulsion, and on the other hand, the coupling agent can also be used to improve the bonding strength between the organic body (thermoplastic resin) and the inorganic body (basalt fiber), thereby improving the mechanical properties of the material.

[0033] Optionally, the emulsifier includes at least one of an alkyl sulfate and an alkyl benzene sulfonate.

[0034] Optionally, the method further includes hydrolyzing the coupling agent in the impregnating agent, wherein the method includes: adding the coupling agent to water, stirring simultaneously, and controlling the pH value to be 3-5; specifically, the water may be slowly stirred, and the coupling agent may be added, and stirred for 0.5-1h until the solution becomes transparent. Controlling the pH value to be 3-5 can ensure the hydrolysis reaction speed.

[0035] It should be noted that when the coupling agent is hydrolyzed, various buffers can be selected as the reagent for adjusting the pH, such as phosphate buffer, etc., which are not specifically limited here.

[0036] It should also be noted that the preparation method of the wetting agent includes: adding polyolefin wax, coupling agent and excess water to the hydrolyzed coupling agent and stirring evenly; or, diluting the polyolefin wax and coupling agent with excess water, adding them to the hydrolyzed coupling agent, and stirring evenly.

[0037] Optionally, the gas for plasma treatment includes at least one of oxygen, nitrogen and argon; the gas pressure for plasma treatment is 0.2-0.6MPa (for example: 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, etc.); the temperature for plasma treatment is 50-100°C (for example: 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, etc.); the power for plasma treatment is 100-1000W (for example: 100W, 300W, 500W, 700W, 900W, 1000W, etc.).

[0038] Optionally, the method of applying the wetting agent to the surface-modified basalt fiber includes: applying the wetting agent to the surface-modified basalt fiber using a rotating oiling roller, wherein the rotation speed of the oiling roller is 50-90r / min, for example: 50r / min, 60r / min, 70r / min, 80r / min, 90r / min, etc.; applying the wetting agent to the surface-modified basalt fiber during the rotation of the oiling roller, and optimizing the rotation speed of the oiling roller can improve the uniformity of the coating. If the rotation speed is too fast, the content of the coated wetting agent will be too low and unevenly distributed. If the rotation speed is too slow, the content of the coated wetting agent will be excessive, resulting in waste.

[0039] Optionally, after the sizing agent is applied to the surface-modified basalt fiber, it is dried at a temperature of 180-250°C (for example, 180°C, 200°C, 220°C, 240°C, 250°C, etc.). Drying under suitable conditions can improve the bonding strength between the sizing agent and the basalt fiber, thereby facilitating the modification of the basalt fiber by the sizing agent, improving the bonding strength between the basalt fiber and the thermoplastic resin, and improving the uniformity of the thermoplastic resin impregnation of the basalt fiber, reducing the difficulty of impregnation, and reducing the problem of yellow spots.

[0040] Optionally, the method for preparing the basalt fiber reinforced thermoplastic prepreg tape further includes: spreading the impregnated modified basalt fiber and heat treating it at a temperature of 70-150° C. In this way, the moisture in the fiber can be further reliably removed, defects such as impregnation bubbles in the subsequent thermoplastic resin impregnation can be avoided, and the bonding strength between the thermoplastic resin and the basalt fiber can be improved.

[0041] It should be noted that the preparation of basalt fiber reinforced thermoplastic prepreg tape can be produced online, for example:

[0042] 1) The basalt ore is melted and homogenized in the tank kiln, drawn through a large leaky plate and then cooled to form basalt fiber, which is then plasma modified by an online plasma treatment device;

[0043] 2) Apply the wetting agent using an oiling roller, perform wetting modification, and dry into an ingot;

[0044] 3) Use the yarn rack to pull and spread the yarn, spread the fibers to 0.1-0.5 mm and arrange them in parallel;

[0045] 4) Preheating;

[0046] 5) placing the preheated fiber into an impregnation mold, and using a screw extruder to extrude thermoplastic resin to impregnate the basalt fiber in an impregnation tank;

[0047] 6) After being pressed and formed by the shaping roller, the basalt fiber prepreg tape is cooled by the cooling roller or cooling system, and then the waste edge cutting machine is used to cut off the defective edges on both sides according to the width of the product, and finally the winder is used to reel it up.

[0048] The equipment used in online production is conventional, which is convenient for factory construction, and is conducive to cost control and high production efficiency. In addition, online production does not need to wait for the fiber formed by the wire drawing of the leak plate to cool before surface treatment, and thus does not need to unwind the entire roll of fiber, that is, yarn release-treatment-winding, which is conducive to improving the consistency of the prepreg tape and ensuring the performance consistency of the prepreg tape.

[0049] It should be noted that the use of large leaky plates for wire drawing can improve the problems of inconsistent buckling of the twisted yarn, poor fiber consistency, and easy knotting compared to small leaky plates, thereby improving the stability of the quality of the prepreg tape.

[0050] The present invention is further described in detail below in conjunction with embodiments.

[0051] Example 1

[0052] The basalt fiber is subjected to plasma treatment to obtain surface-modified basalt fiber; wherein the gas for the plasma treatment is oxygen; the gas pressure for the plasma treatment is 0.2 MPa; the temperature for the plasma treatment is 100° C.; and the power for the plasma treatment is 100W.

[0053] The sizing agent is applied to the surface-modified basalt fiber to obtain the sizing-modified basalt fiber; wherein the raw materials for preparing the sizing agent include: 20% by mass of polyethylene wax, 4% by mass of silane coupling agent and 3% by mass of alkyl sulfate, and the balance is deionized water; the coupling agent needs to be hydrolyzed, and the pH is adjusted to 3. The sizing agent is applied by applying with an oiling roller at a rotation speed of 50 r / min; and drying at a temperature of 180°C after application.

[0054] The impregnated modified basalt fibers are spread and heat treated at 70°C; then, thermoplastic resin (polyethylene) is impregnated into the impregnated modified basalt fibers to obtain basalt fiber reinforced thermoplastic prepreg tapes, wherein the fiber content is 31.3%.

[0055] Example 2

[0056] The basalt fiber is subjected to plasma treatment to obtain surface-modified basalt fiber; wherein the gas for the plasma treatment is argon; the gas pressure for the plasma treatment is 0.6 MPa; the temperature for the plasma treatment is 50° C.; and the power for the plasma treatment is 1000W.

[0057] The sizing agent is applied to the surface-modified basalt fiber to obtain the sizing-modified basalt fiber; wherein the raw materials for preparing the sizing agent include: 15% by mass of polypropylene wax, 1% by mass of silane coupling agent and 1% by mass of alkylbenzene sulfonate, and the balance is deionized water; the coupling agent needs to be hydrolyzed, and the pH is adjusted to 5. The sizing agent is applied by applying with an oiling roller at a rotation speed of 90 r / min; and drying at a temperature of 250° C. after application.

[0058] The impregnated modified basalt fibers are spread and heat treated at 150°C; then, thermoplastic resin (nylon) is impregnated into the impregnated modified basalt fibers to obtain basalt fiber reinforced thermoplastic prepreg tapes, wherein the fiber content is 32%.

[0059] Example 3

[0060] The basalt fiber is subjected to plasma treatment to obtain surface-modified basalt fiber; wherein the gas for the plasma treatment is argon; the gas pressure for the plasma treatment is 0.4 MPa; the temperature for the plasma treatment is 80° C.; and the power for the plasma treatment is 500W.

[0061] The sizing agent is applied to the surface-modified basalt fiber to obtain the sizing-modified basalt fiber; wherein the raw materials for preparing the sizing agent include: 20% by mass of polypropylene wax, 10% by mass of silane coupling agent and 8% by mass of alkylbenzene sulfonate, and the balance is deionized water; the coupling agent needs to be hydrolyzed, and the pH is adjusted to 5. The sizing agent is applied by applying with an oiling roller at a rotation speed of 60 r / min; and drying at a temperature of 220° C. after application.

[0062] The impregnated modified basalt fibers are spread and heat treated at 100° C. Then, thermoplastic resin (nylon) is impregnated into the impregnated modified basalt fibers to obtain basalt fiber reinforced thermoplastic prepreg tapes, wherein the fiber content is 32.4%.

[0063] Example 4

[0064] The only difference between Example 4 and Example 1 is that the fiber content of the basalt fiber reinforced thermoplastic prepreg tape is 50%.

[0065] Comparative Example 1

[0066] The difference between Comparative Example 1 and Example 1 is that the basalt fiber is not plasma-modified and sizing-modified, and other parameters and methods of impregnating the thermoplastic resin refer to Example 1.

[0067] Comparative Example 2

[0068] The difference between Comparative Example 2 and Example 1 is that the glass fiber is impregnated with thermoplastic resin without being modified by plasma and sizing agent, and the impregnation parameters and method are the same as those of Example 1, wherein the fiber content is 50%.

[0069] The basalt fiber reinforced thermoplastic prepreg tapes of Example 1, Example 4 and Comparative Example 1, Comparative Example 2 were prepared into long cut materials through LFT equipment, and then the long cut materials were made into tensile and bending specimens by an injection molding machine. The tensile and bending properties of the specimens were tested under a mechanical testing machine, and the properties are shown in the following table.

[0070] Test items Fiber Content Tensile Strength Elongation at break Bending Strength Flexural modulus Test Standards ISO 3451-1 ISO 527-2 ISO 527-2 ISO 178 ISO 178 Test conditions 800℃ / 1h 2mm / min 2mm / min 2mm / min 2mm / min unit ％ MPa ％ MPa MPa Comparative Example 1 31 25.4 4.2 40.97 2542 Comparative Example 2 50 500.1 - - - Example 1 31.3 53.41 9.95 73.7 4200 Example 4 50 712.1 - - -

[0071] According to the test results of Comparative Example 1 and Example 1, under the condition of basically the same fiber content, the tensile properties of the basalt fiber and polyethylene after plasma surface treatment and impregnation agent modification are improved by more than 1 times, and the bending properties are improved by 80%, which proves that the modification effect is excellent.

[0072] According to the test results of Comparative Example 2 and Example 4, when the prepreg is prepared using modified basalt fiber and the fiber content reaches 50%, the tensile strength exceeds 700 MPa, which is higher than the requirement of 500 MPa for glass fiber prepreg.

[0073] In summary, the preparation method of the basalt fiber reinforced thermoplastic prepreg of the present invention is beneficial to improve the bonding strength between the modified basalt fiber and the thermoplastic resin, improve the mechanical properties of the material, improve the uniformity of impregnation, reduce the difficulty of impregnation, and reduce the problem of yellow spots by surface modification and impregnation modification of the basalt fiber.

[0074] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a basalt fiber reinforced thermoplastic prepreg tape, characterized in that: include: Plasma treatment is performed on basalt fibers to obtain surface-modified basalt fibers; Applying a sizing agent to the surface-modified basalt fiber to obtain a sizing-modified basalt fiber; The thermoplastic resin is impregnated into the impregnated modified basalt fiber; wherein, The raw materials for preparing the sizing agent include: polyolefin wax, coupling agent and emulsifier.

2. The method for preparing basalt fiber reinforced thermoplastic prepreg tape according to claim 1, characterized in that: The wetting agent comprises, by mass percentage, 15-25% of the polyolefin wax, 1-10% of the coupling agent, 1-8% of the emulsifier, and the balance is water.

3. The method for preparing basalt fiber reinforced thermoplastic prepreg tape according to claim 1, characterized in that: The polyolefin wax includes at least one of polyethylene wax and polypropylene wax.

4. The method for preparing basalt fiber reinforced thermoplastic prepreg tape according to claim 1, characterized in that: The coupling agent includes a silane coupling agent.

5. The method for preparing basalt fiber reinforced thermoplastic prepreg tape according to claim 1, characterized in that: The emulsifier includes at least one of an alkyl sulfate and an alkyl benzene sulfonate.

6. The method for preparing basalt fiber reinforced thermoplastic prepreg tape according to claim 1, characterized in that: The method also includes hydrolyzing the coupling agent in the impregnating agent. The method for hydrolyzing the coupling agent includes: adding the coupling agent to water, stirring simultaneously, and controlling the pH value to be 3-5.

7. The method for preparing basalt fiber reinforced thermoplastic prepreg tape according to claim 1, characterized in that: The gas for the plasma treatment includes at least one of oxygen, nitrogen and argon; the gas pressure for the plasma treatment is 0.2-0.6MPa; the temperature for the plasma treatment is 50-100°C; and the power for the plasma treatment is 100-1000W.

8. The method for preparing basalt fiber reinforced thermoplastic prepreg tape according to claim 1, characterized in that: The method of applying the sizing agent to the surface-modified basalt fiber comprises: applying the sizing agent to the surface-modified basalt fiber using a rotating oiling roller, wherein the rotation speed of the oiling roller is 50-90 r / min; and After the sizing agent is applied to the surface-modified basalt fiber, it is dried at a temperature of 180-250°C.

9. The method for preparing basalt fiber reinforced thermoplastic prepreg tape according to claim 1, characterized in that: The preparation method of the basalt fiber reinforced thermoplastic prepreg tape further comprises: spreading the impregnated and modified basalt fibers and heat treating them at a temperature of 70-150°C.

10. A basalt fiber reinforced thermoplastic prepreg tape, characterized in that: The basalt fiber reinforced thermoplastic prepreg tape is prepared by the preparation method of basalt fiber reinforced thermoplastic prepreg tape according to any one of claims 1 to 9.