Rapidly cured and molded fiber fabric prepreg and preparation method thereof

Abstract

The invention relates to the technical field of polymer fiber fabrics, and particularly discloses a rapidly cured and molded fiber fabric prepreg and a preparation method thereof.The fiber fabric prepreg is prepared from, by weight, 30-35 parts of modified vinyl resin, 0.4-0.6 part of an initiator, 0.1-0.2 part of a polymerization inhibitor, 3-4 parts of a thickening agent, 0.5-1 part of a release agent and 60-65 parts of a fiber fabric, the modified vinyl resin is used as the raw material, the use ratio of the modified vinyl resin is optimized, and the preparation method of the modified vinyl resin is researched, so that the compression molding time of the prepreg can be greatly shortened, demolding is easy in production, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer fiber fabrics, and in particular relates to a fast-curing fiber fabric prepreg and a preparation method thereof. Background Art

[0002] The rapid development of the automotive industry in recent years has put forward higher requirements on the performance of various automotive materials, especially the lightweight of automobiles, which has put forward the requirements for automotive prepregs to develop in the direction of light weight and high strength.

[0003] Epoxy resin has good bonding properties, strong mechanical properties and chemical stability, and its comprehensive performance is excellent while meeting the requirements of lightweighting. Therefore, in order to achieve lightweight development of vehicles, automotive prepregs mostly use epoxy resin systems.

[0004] In the prior art, a Chinese patent with publication number CN108047652A discloses an epoxy resin composition and a method for preparing a prepreg thereof, which uses a multifunctional epoxy resin and a liquid bisphenol A epoxy resin as a matrix, DDS and MCA10 as a compound curing agent, boron trifluoride monoethylamine as an accelerator, a toughening agent thermoplastic resin and a thixotropic agent TS720 as a modifier, and mixes them in a mixing kettle to obtain a low-temperature curing heat-resistant epoxy resin composition, and prepares the prepreg by a hot melt method. The heat resistance of the prepreg is improved, and it is suitable for the fields of automobiles, rail transportation, etc.

[0005] However, the above-mentioned existing epoxy resin system used to prepare automotive prepregs has problems such as long molding time, difficulty in demoulding and harsh storage conditions. Summary of the invention

[0006] Based on the technical problems existing in the existing epoxy resin prepregs mentioned above, the present invention provides a fast-curing fiber fabric prepreg and a preparation method thereof. By using modified vinyl resin as a raw material, optimizing its use ratio and studying its preparation method, the prepreg molding time can be greatly reduced. The specific method is as follows:

[0007] Firstly, the present invention provides a fast-curing fiber fabric prepreg, which is composed of the following raw materials in parts by weight: 30 to 35 parts of modified vinyl resin, 0.4 to 0.6 parts of initiator, 0.1 to 0.2 parts of inhibitor, 3 to 4 parts of thickener, 0.5 to 1 parts of release agent and 60 to 65 parts of fiber fabric.

[0008] Furthermore, the modified vinyl resin meets the following technical indicators: viscosity (23° C.) 440-500 mPa·s, solid content 59-62%, acid value 5-10 mgKOH / g.

[0009] Furthermore, the initiator is tert-butyl perbenzoate, the inhibitor is p-phenol, the thickener is isocyanate, and the release agent is zinc stearate.

[0010] Furthermore, the fiber fabric includes any one or two of carbon fiber, glass fiber and basalt fiber.

[0011] Furthermore, the fiber fabric is selected to meet the following specification parameters: linear density 100-800tex, elastic modulus 70-260GPa, elongation at break 1.5-5, and fiber tow 3-24k.

[0012] The present invention also provides a method for preparing a fast-curing fiber fabric prepreg, comprising the following steps: adding a modified vinyl resin, an initiator and an inhibitor into a pulping device and rapidly stirring them, adding a release agent thereto and continuing to stir after the stirring is completed, reducing the rotation speed and then adding a thickener thereto and stirring to form a resin paste liquid; uniformly coating the resin paste liquid on the fiber fabric, sealing and storing it after the coating is completed, thickening it, and finally preparing the fiber fabric prepreg.

[0013] Furthermore, the beating device has a rotation speed of 1100 to 1500 r / min.

[0014] Beneficial effects of the present invention:

[0015] 1. The present invention uses vinyl resin as the prepreg material of the fiber fabric, and modifies the vinyl resin by polyurethane, thereby increasing the bonding ability of the vinyl resin material and the fiber fabric, improving its prepreg effect on the fiber fabric, reducing its curing molding time and ensuring the mechanical properties of the prepreg after molding. Compared with the original epoxy resin system, the curing time of the prepreg prepared by the present invention is shortened from 20 minutes to 3 minutes, and the mechanical properties are slightly improved.

[0016] 2. The prepreg prepared in the present invention has a stronger bonding ability with the modified vinyl resin, and can be demoulded without spraying a release agent after molding, which optimizes the production process and reduces production consumables. At the same time, compared with the original epoxy resin system, the technical solution provided by the present invention reduces the total material cost by 20%, saving production costs and is very suitable for large-scale industrial use. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a physical picture of the preparation of a fast-cured fiber fabric prepreg and a preparation method thereof of the present invention. DETAILED DESCRIPTION

[0018] Example 1

[0019] This embodiment provides a fast solidification fiber fabric prepreg, wherein the fiber fabric uses 600g-12K twill carbon cloth, and its specifications are: linear density 600tex, elastic modulus 240GPa, elongation at break 1.6, fiber tow 12k. The prepreg is composed of the following raw materials in parts by weight: 31 parts of modified vinyl resin, 4.8 parts of tert-butyl perbenzoate as initiator, 0.2 parts of p-phenol as inhibitor, 3.2 parts of isocyanate as thickener, 0.8 parts of zinc stearate as release agent and 60 parts of 600g-12K twill carbon cloth.

[0020] In this embodiment, the modified vinyl resin uses TDI to modify the vinyl resin, and the modified vinyl resin includes 32 parts of TDI and 68 parts of vinyl resin. The modified vinyl resin meets the following technical indicators: viscosity (23°C) 470mPa·s, solid content 60%, acid value 8mgKOH / g. The modified vinyl resin has a tensile strength of 80MPa, a tensile elastic modulus of 3500MPa, an elongation at break of 3%, a flexural strength of 130MPa, and a flexural elastic modulus of 3400MPa.

[0021] The present embodiment also provides a method for preparing a fiber fabric prepreg for rapid curing, comprising the following steps: first, weigh the raw materials according to the weight composition of the above-mentioned fiber fabric prepreg, add modified vinyl resin, tert-butyl perbenzoate and p-phenol into a beater, control the speed at 1100 rpm, and stir quickly for 3 minutes. Then add zinc stearate thereto, keep the speed and continue stirring for 5 minutes. Finally, add isocyanate thereto, reduce the speed by 500 rpm, and stir for 10 minutes to make a resin paste glue. The prepared resin paste glue is evenly coated on the twill carbon cloth to ensure that the glue completely soaks the carbon cloth. After the coating is completed, the two sides of the carbon cloth are sealed with a release film on both sides and placed in a 40-degree drying room for thickening for 24 hours, and finally a fiber fabric prepreg for rapid curing is obtained. The prepreg can be stored at room temperature.

[0022] Example 2

[0023] The difference between this embodiment and embodiment 1 is that the raw material proportions of the fiber fabric prepreg are different. Specifically, this embodiment uses 600g-12K twill carbon cloth, and the prepreg is composed of the following raw materials in parts by weight: 31.75 parts of modified vinyl resin, 4 parts of tert-butyl perbenzoate as an initiator, 0.15 parts of p-phenol as an inhibitor, 3.4 parts of isocyanate as a thickener, 0.7 parts of zinc stearate as a release agent, and 60 parts of 600g-12K twill carbon cloth.

[0024] Comparative Example 1

[0025] The difference between this comparative example and Example 1 is that the resin material used is unmodified vinyl resin, and the other components and preparation method are the same as those of Example 1.

[0026] Comparative Example 2

[0027] The difference between this comparative example and Example 1 is that the raw material components are different, specifically including the following raw material components in parts by weight: 25 parts of modified vinyl resin, 4.8 parts of tert-butyl perbenzoate as an initiator, 0.2 parts of p-phenol as an inhibitor, 3.2 parts of isocyanate as a thickener, 0.8 parts of zinc stearate as a release agent and 65 parts of 600g-12K twill carbon cloth.

[0028] Comparative Example 3

[0029] The difference between this comparative example and Example 1 is that the proportions of the modified vinyl resin components are different. Specifically, the modified vinyl resin includes 40 parts of TDI and 60 parts of vinyl resin.

[0030] Comparative Example 4

[0031] The difference between this comparative example and Example 1 is that the prepreg is prepared using an epoxy resin system, and the specific steps are prepared by the following steps: TDI urea is slowly added to the epoxy resin according to a weight ratio of 1:2, heated while stirring, and the temperature is controlled at 50 degrees, and the non-meal is completely added, stirred for 30 minutes, and then ground to 10um with three rollers, and stirred for 15 minutes after the grinding is completed to obtain an intermediate, and the epoxy resin, nitrile rubber, and EPN are mixed and stirred and heated to 100 degrees, and ECN is added thereto, and the temperature is continued to rise to 120 degrees, and the constant temperature is maintained for 2-3 hours, and stirring is continued. Then, the heating temperature is reduced to 60 degrees, and a powdered dicyandiamide curing agent and an intermediate are added, stirred under vacuum conditions, and a pre-reaction is carried out for 20 minutes to obtain an epoxy resin composition, and finally the epoxy composition is applied to a 12k carbon cloth by a hot melt method to obtain an epoxy carbon fiber prepreg, and stored at a temperature of -18 degrees.

[0032] The prepreg prepared in this comparative example specifically includes the following raw materials in parts by weight: 24.9 parts of modified epoxy resin, 4 parts of EPN as an initiator, 6.4 parts of ECN, 2 parts of powdered dicyandiamide curing agent, 2.4 parts of nitrile rubber, 0.3 TDI urea and 60 parts of 600g-12K twill carbon cloth.

[0033] The prepregs obtained from the above examples and comparative examples have the following properties after molding test:

[0034] Table 1: Performance test table of fiber fabric prepreg prepared in Examples & Comparative Examples

[0035]

[0036]

[0037] Analysis of experimental results: From the above experimental results, it can be seen that the prepreg prepared in the embodiment of the present invention only takes three minutes to be molded, and can be easily demolded without the need for additional spraying of a release agent. In addition, the various mechanical properties of the product can be maintained at a high level, which fully meets the existing automotive industry's requirements for lightweight and high-strength prepregs.

[0038] When unmodified vinyl resin is used as the raw material, the molding time and demolding performance are improved compared to the prepreg prepared by the existing epoxy resin system, but the mechanical properties will be greatly reduced. Compared with the prepreg prepared in Example 1 and Example 2, the tensile strength and bending strength are reduced by about half, which can no longer meet the standards used in automobiles.

[0039] When the specific gravity of the modified vinyl resin in the raw materials is reduced, the pre-impregnation effect of the resin on the fiber fabric will be reduced, which will in turn affect the curing effect of the molded prepreg and reduce its mechanical properties and strength.

[0040] When the ratio of the modified components in the modified vinyl resin is changed in the raw materials, the molding time will increase and the mechanical properties will decrease.

[0041] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view. In addition, it should be understood that although this specification is described in accordance with the implementation methods, it does not include only one technical solution. This narrative of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in the embodiments can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A fast curing fiber fabric prepreg, characterized in that: The fiber fabric prepreg is composed of the following raw materials in parts by weight: 30-35 parts of modified vinyl resin, 0.4-0.6 parts of initiator, 0.1-0.2 parts of inhibitor, 3-4 parts of thickener, 0.5-1 parts of release agent and 60-65 parts of fiber fabric.

2. The fast curing fiber fabric prepreg according to claim 1, characterized in that: The modified vinyl resin is modified by polyurethane, and the modified vinyl resin is composed of the following raw materials in parts by weight: 30 to 35 parts of polyurethane and 65 to 70 parts of vinyl resin, and the polyurethane includes any one of TDI, MDI and NDI.

3. The fast curing fiber fabric prepreg according to claim 2, characterized in that: The modified vinyl resin meets the following technical indicators: viscosity (23° C.) 440-500 mPa•s, solid content 59-62%, and acid value 5-10 mgKOH / g.

4. The fast curing fiber fabric prepreg according to claim 1, characterized in that: The initiator is tert-butyl perbenzoate, the inhibitor is p-phenol, the thickener is isocyanate, and the release agent is zinc stearate.

5. The fast curing fiber fabric prepreg according to claim 1, characterized in that: The fiber fabric includes any one or two of carbon fiber, glass fiber and basalt fiber.

6. The fast curing fiber fabric prepreg according to claim 5, characterized in that: The fiber fabric is selected to meet the following specification parameters: linear density 100-800 tex, elastic modulus 70-260 GPa, elongation at break 1.5-5, and fiber tow 3-24k.

7. A method for preparing a fast curing fiber fabric prepreg as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: Add modified vinyl resin, initiator and inhibitor into a pulping device and stir rapidly. After stirring, add a release agent and continue stirring. After reducing the speed, add a thickener and stir to form a resin paste. Evenly coat the resin paste on the fiber fabric. After coating, seal and store, thicken, and finally form a fiber fabric prepreg.

8. The method for preparing a fast curing fiber fabric prepreg according to claim 7, characterized in that: The beating device has a rotation speed of 1100-1500 r / min.

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