KR20140005409A - Thermoplastic prepreg and method for producing the same - Google Patents

Abstract

Disclosed are: a thermoplastic prepreg in which a thermoplastic resin is impregnated into a reinforcing fiber and which has an excellent degree of impregnation and mechanical strength; and a preparation method thereof. The method for preparing the thermoplastic prepreg comprises the steps of: supplying a first thermoplastic resin film to one or more surfaces of a sheet-shaped reinforcing fiber; supplying a second thermoplastic resin film onto the first thermoplastic resin film; and heating and pressurizing the first thermoplastic resin film and the second thermoplastic resin film so as to impregnate the first thermoplastic resin film into the reinforcing fiber and to join the first thermoplastic resin film and the second thermoplastic resin film, wherein the melt flow index (MI) of the first thermoplastic resin film is greater than that of the second thermoplastic resin film in heating and pressurization steps.

Description

Thermoplastic prepreg and its manufacturing method {Thermoplastic prepreg and method for producing the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic prepreg and a method of manufacturing the same, and more particularly, to a thermoplastic prepreg impregnated with a reinforced fiber and having excellent impregnation and mechanical strength. And to a method for producing the same.

Prepreg is an abbreviation of "Preimpregnated Material," and refers to a product in the form of a sheet in which a matrix is impregnated with a reinforcing fiber, and used as an intermediate material for forming a composite material. 1 is a view for explaining a conventional prepreg configuration (A) and a photo (B) showing an example of the prepreg. As shown in FIG. 1A, the reinforcing fibers 12 and the binder 11 are integrated to form a prepreg 13, and as shown in FIG. 1B, the prepreg 13 is a sheet. It is manufactured in the form of a sheet, wound on a paper roll 14, and cut and used to a desired length in use. The prepreg 13 may be divided into a unidirectional prepreg in which the reinforcing fibers 12 are aligned in one direction, and a woven prepreg in which the reinforcing fibers 12 are formed in a woven form. 1B shows an example of one-way prepreg.

In the normal prepreg 13, carbon fiber having high strength and elasticity is used as the reinforcing fiber 12, and a polymer resin is mainly used as the binder 11, for example, Thermosetting resins such as epoxy resins, phenol resins, unsaturated polyester resins, melamine resins and cyanate ester resins, polypropylene, polyethylene, polyamides, polystyrenes, polyesters, polycarbonates, thermoplastic polyurethanes, polyacetals, Various thermoplastic resins such as polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, ABS resin, polyetherimide, polyether ether ketone, polyphenylene sulfide, polylactic acid and the like can be used.

The reason why prepreg is applied to the molding of composite materials can be found in performance and price. In terms of physical properties, it is possible to precisely control the content and arrangement of reinforcing material (reinforcement fiber), thereby realizing the material properties of the designed material. It is possible to manufacture a molded article having a high fiber volume ratio, the mechanical strength of the molded article is excellent, thereby enabling the implementation of the optimum physical properties, there is an advantage that the weight of the part can be reduced. Compared with other composite molding process, the composite material forming process using prepreg uses the intermediate material, so the price of raw material is high, but the molding process is clean and simple, and the process cost can be reduced. have. The prepreg is mainly in the form of a sheet, so it is easy to handle, saves energy costs during molding, and can reduce the number of parts required for processing due to the nature of cutting molding, and thus the aviation / space, automobiles, sports / leisure, civil engineering / building It is widely used as an intermediate material for composite molding in many industries.

As described above, the prepreg may be classified into a thermosetting prepreg to which a thermosetting resin is applied, and a thermoplastic prepreg to which a thermoplastic resin is applied, and a thermosetting prepreg that is relatively easy to manufacture was mainly used in the early stages of prepreg development. Increasingly, thermoplastic prepregs that are compatible with and capable of recycling are being increased. The manufacturing method of the thermoplastic prepreg is a film process, a powder coating process, a co-mingled yarn process, a direct melt process, Various solutions such as a solution process, but in view of economics, ease of production, quality of the molding, etc., the film method is most widely used.

FIG. 2 is a view illustrating a conventional thermoplastic prepreg production process. FIG. 2A is a manufacturing process diagram of a woven thermoplastic prepreg 28a, and FIG. 2B is a manufacturing process diagram of a unidirectional thermoplastic prepreg 28b. The two processes are identical except for the addition of reinforcing fibers. Referring to FIG. 2A, in the roll 20a, the reinforcing fibers 21a in the form of weaved fabric are released, and both sides (upper part) of the reinforcing fibers 21a supplied from the roll 20a are released. Surface and lower surface) or end faces, the resin films 22a and 22b obtained by processing the thermoplastic resin in the form of a film are supplied through a first feeder (給 紙, 23a, 23b), and then the second paper feeder Release materials 24a and 24b are supplied from (second feeder, 25a and 25b). The reinforcing fibers 21a in which the resin films 22a and 22b are laminated pass through the heating / pressing device 26. The said heating / pressure apparatus 26 heats the resin films 22a and 22b to the temperature more than melting | fusing point, and melt-impregnates the resin of the resin films 22a and 22b to the reinforcing fiber 21a. When the heating / pressurization is completed, the release materials 24a and 24b are recovered through separate take-up rolls 27a and 27b, thereby manufacturing the fabric-type thermoplastic prepreg 28a. Referring to B of FIG. 2, the fiber-like reinforcing fiber strands 30 are unwound in a warp form unfolded in one direction from a plurality of failures 20b and creel, and are evenly arranged and arranged in one direction. A reinforcing fiber 21b of the form is formed, and the reinforcing fiber 21b is used for producing the unidirectional thermoplastic prepreg 28b, and the rest of the process is the same as that shown in A of FIG. As the resin films 22a and 22b, in general, a non-stretching film is used, but in some cases, a stretched film, a resin fiber fabric, a resin nonwoven fabric, or the like is used. A modified film of may be used. In the manufacturing process, in order to prevent the melted resin from sticking to the heating / pressing device 26, the release materials 24a and 24b supplied from the second paper feeders 25a and 25b may be used. 24a and 24b are commonly used a release paper made of paper and a release film made of a polymer material.

As described above, the manufacturing method of the thermoplastic prepreg using the film method is simple in configuration, and when changing the variety of the prepreg, only the film can be selectively changed, which is advantageous for the production of various varieties, the production yield is high, and the resin flushing is performed. Since there is no need for a separate pre / post treatment process such as dissolution of resin and compounding of resin, there is an advantage that the working environment is clean. However, in the case of the thermoplastic prepreg manufacturing process using the film method, the melt viscosity (viscosity, viscosity) of the thermoplastic resin is very high, it is difficult to uniformly impregnate the resin in the reinforcing fibers, and to produce a high quality thermoplastic prepreg with high impregnation degree However, there is a problem in that the production temperature is excessively increased or the production speed is set low. In addition, in order to lower the melt viscosity of the thermoplastic resin and improve the impregnation, heating to a temperature much higher than the melting point of the resin film or slowing down the production speed to increase the high temperature residence time results in thermal decomposition of the resin, resulting in the prepreg There is a possibility that the physical properties are lowered. Due to this difficulty of impregnation, in spite of the deterioration of physical properties, a low molecular weight resin film having a low melt viscosity may be used, but in this case, the melt viscosity is lower than that of a resin having a large molecular weight, which is advantageous for production. There is a problem that mechanical properties are significantly lowered.

It is therefore an object of the present invention to provide a thermoplastic prepreg in which a thermoplastic resin is used as a matrix (substrate) and excellent in impregnation degree and mechanical strength, and a method of manufacturing the same.

Another object of the present invention is to improve the impregnation with a resin film having a low melt viscosity, and to improve mechanical properties with a resin film having a high melt viscosity, thereby providing a method of easily and economically producing a thermosetting prepreg. It is.

In order to achieve the above object, the present invention, the step of supplying a first thermoplastic resin film on at least one side of the reinforcing fibers in the form of a sheet; Supplying a second thermoplastic resin film on the first thermoplastic resin film; And heating and pressing the first thermoplastic resin film and the second thermoplastic resin film to impregnate the first thermoplastic resin film with the reinforcing fiber, and to bond the first thermoplastic resin film and the second thermoplastic resin film together. And a melt flow index (MI) of the first thermoplastic resin film is greater than a melt flow index (MI) of the second thermoplastic resin film in the heating and pressurizing step. to provide.

In addition, the present invention, the sheet-like reinforcing fibers; A first thermoplastic resin film impregnated in the reinforcing fiber; And a second thermoplastic resin film bonded to the first thermoplastic resin film, wherein a melt flow index MI of the first thermoplastic resin film is greater than a melt flow index MI of the second thermoplastic resin film. It provides a thermoplastic prepreg.

According to the thermoplastic prepreg and the manufacturing method thereof according to the present invention, a thermoplastic prepreg excellent in impregnation and mechanical properties (strength, etc.) can be easily produced even in a simple three step process. In addition, according to the present invention, by applying two or more kinds of resin films, by combining the melt flow index (MI), molecular weight, resin properties and the like affecting the degree of impregnation and mechanical properties, thermoplastics excellent in both the degree of impregnation and mechanical properties Prepregs can be prepared.

1 is a view for explaining a conventional prepreg configuration and a photograph showing an example of the prepreg.
2 shows a conventional thermoplastic prepreg production process.
3 is a view showing a method of manufacturing a thermoplastic prepreg according to an embodiment of the present invention.
4 shows a conventional heating / pressure device that can be used in the present invention.
5 is a view showing the structure of a thermoplastic prepreg according to an embodiment of the present invention.
6a to 6c is a view showing a thermoplastic prepreg manufacturing method according to an embodiment of the present invention and a comparative example.
7 is a cross-sectional photograph and cross-sectional conceptual view of a thermoplastic prepreg produced according to the Examples and Comparative Examples of the present invention.
8 is a cross-sectional photograph of a hybrid thermoplastic prepreg according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

3 is a view showing a method of manufacturing a thermoplastic prepreg according to an embodiment of the present invention. As shown in FIG. 3, in order to manufacture the thermoplastic prepreg according to the present invention, first, the first thermoplastic resin films 42a and 42b are supplied to at least one surface of the reinforcing fibers 41 in the form of sheets. Next, the second thermoplastic resin films 44a and 44b are supplied (stacked) on any one or more surfaces of the first thermoplastic resin films 42a and 42b, and any one of the first thermoplastic resin films 42a and 42b is supplied. Second thermoplastic resin films 44a and 44b are laminated on one or both surfaces. The laminated reinforcing fibers 41, the first thermoplastic resin films 42a and 42b, and the second thermoplastic resin films 44a and 44b are heated and pressurized while passing through the heating / pressing device 48, and the first The thermoplastic resin films 42a and 42b are impregnated in the reinforcing fibers 41, and the first thermoplastic resin films 42a and 42b and the second thermoplastic resin films 44a and 44b are bonded to each other. In the heating and pressing step, the melt flow index (MI) of the first thermoplastic resin films 42a and 42b is greater than the melt flow index MI of the second thermoplastic resin films 44a and 44b. It is set to.

The melt flow index MI of the first thermoplastic resin films 42a and 42b and the second thermoplastic resin films 44a and 44b is impregnated with the reinforcing fibers 41 and the first thermoplastic resin films 42a and 42b. The property is superior to the impregnation of the reinforcing fibers 41 and the second thermoplastic resin films 44a and 44b, and the mechanical properties (strength and the like) of the second thermoplastic resin films 44a and 44b are the first thermoplastic resin film. Within the range superior to 42a, 42b, it can be set suitably. For example, according to one embodiment of the present invention, the melt flow index MI of the first thermoplastic resin films 42a and 42b with respect to the melt flow index MI of the second thermoplastic resin films 44a and 44b. The ratio ((MI of first thermoplastic resin film) / (MI of second thermoplastic resin film)) is at least 1.01 times, preferably at least 1.1 times, more preferably at least 2 times, most preferably at least 5 times. . Here, if the melt flow index (MI) ratio is too small, it is impossible to produce a thermoplastic prepreg excellent in both the impregnation and mechanical properties (strength, etc.). The melt flow index (MI) is a number representing the number of g of the resin passed through the hole having a certain cross-sectional area for 10 minutes at a specific temperature and pressure, the higher the melt flow index (MI), the higher the fluidity of the resin, the higher the melt viscosity Lowers. In the present invention, the melt flow index (MI) is measured according to ASTM D1238, the measurement temperature is the heating / pressure of the first thermoplastic resin film (42a, 42b) and the second thermoplastic resin film (44a, 44b) The temperature of the stage (maximum heating temperature if the heating is done in several stages), measuring load is 2160 g, resin dissolution time is 10 minutes, and measuring unit is grams (g / 10 minutes). The temperature of the heating / pressing step depends on the resin used, but is at least 5 ° C. higher than the melting point of the resin, for example, 10-30 ° C. higher than the melting point of the resin, specifically, high density polyethylene (HDPE). It is about 260 degreeC in the case of polyester, such as polyethylene at 190 degreeC, and polycarbonate (PC), and a polyethylene terephthalate (PET).

According to another embodiment of the present invention, at a processing temperature of the resin film, the melt flow index MI of the first thermoplastic resin films 42a and 42b is 5 or more, preferably 10 or more, more preferably 15 or more. (As long as it can be molded into a prepreg, the higher the value, for example, the upper limit may be 50), and the melt flow index MI of the second thermoplastic resin films 44a and 44b is less than 5, Preferably it is 1 or less, More preferably, it is 0.5 or less (as long as it can be shape | molded with prepreg, a lower value is good, for example, a minimum may be 0.01). In this case, when the melt flow index MI of the first thermoplastic resin films 42a and 42b is too small, impregnation does not occur to the inside of the reinforcing fiber, so that an unimpregnated portion (pores, voids) occurs in the prepreg. When the melt flow index MI of the second thermoplastic resin films 44a and 44b is too large, there is a possibility that the improvement of physical properties of the prepreg may be insufficient.

The reinforcing fibers 41 may be used without limitation, conventional reinforcing fibers used for the production of prepreg, for example, high strength and elastic carbon fibers, glass fibers, aramid fibers ( aramid fibers, basalt fibers, boron fibers, and the like. In addition, the reinforcing fibers 41 may be fibers arranged in one direction or may be fibers in the form of a fabric, and the thickness thereof is not particularly limited as long as it can be used as the reinforcing fibers. The reinforcing fiber supply device 40 for supplying the reinforcing fibers 41 is a general supply device for supplying the woven or unidirectional reinforcing fibers 41.

The first thermoplastic resin films 42a and 42b supplied (laminated) to the upper and / or lower surfaces of the reinforcing fibers 41 have a melt viscosity such that the reinforcing fibers 41 are easily impregnated when heated and pressed. Made of small resin. The first thermoplastic resin films 42a and 42b may be made of various conventional thermoplastic resins, and preferably polypropylene (PP), polyethylene (PE), polyamide (PA), polystyrene (PS), and polyester (PES), polycarbonate (PC), thermoplastic polyurethane (TPU), polyacetal (POM), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), ABS (acrylonitrile butadiene styrene resin) resin, polyetherimide (PEI), polyetheretherketon (PEEK), polyphenylene sulfide (PPS) and polylactic acid, PLA) and a resin selected from the group consisting of. The thickness of the first thermoplastic resin films 42a and 42b is not particularly limited as long as the reinforcing fibers 41 can be impregnated, but is, for example, 0.01 mm to 2 mm. As shown in FIG. 3, the first thermoplastic resin films 42a and 42b are supplied by the first paper feeders 43a and 43b, and the first paper feeders 43a and 43b are used to feed the raw material in the form of a film. It is a normal paper feeding device which supplies continuously. The second thermoplastic resin films 44a and 44b may also be made of various conventional thermoplastic resins satisfying the melt flow index MI. For example, the first thermoplastic resin films 42a and 42b may be formed. It may be made of various thermoplastic resins as described in the thermoplastic resin to be formed. The thickness of the second thermoplastic resin films 44a and 44b is not particularly limited as long as it can improve the physical properties of the thermoplastic prepreg, but is, for example, 0.01 mm to 2 mm.

In the present invention, the first thermoplastic resin films 42a and 42b and the second thermoplastic resin films 44a and 44b have different molecular weights but are made of the same type of resin, or have compatibility or compatibility between resins. It is preferable that it consists of heterogeneous resin which does not fall in physical property at an interface. As an example in the case of using a heterogeneous resin, compatible polycarbonate (PC) and polyethylene terephthalate (PET) can be used. Both PET and PC have similar processing temperatures of around 260 ° C, while PET has a very high melt flow index (MI) of over 100 at 260 ° C, while PC has a relatively low melt flow index (MI) of less than 10 and mechanical Physical properties are superior to PC. However, it is difficult to impregnate the reinforcing fibers due to the high melt viscosity of the PC at the processing temperature, and to increase the fluidity by increasing the processing temperature, thermal decomposition of the resin occurs, it is difficult to make a prepreg. Therefore, prepreg is produced by using PET as the first thermoplastic resin films 42a and 42b which are resins for impregnation, and by using the PC having strong mechanical properties as the second thermoplastic resin films 44a and 44b which are resins for enhancing properties. If it is, it is possible to produce a thermoplastic prepreg excellent in both impregnation degree and mechanical properties. In addition, if necessary, three or more kinds of various thermoplastic resin films may be laminated to produce thermoplastic prepregs having various functions.

Usually, as the molecular weight increases, mechanical properties such as tensile strength, flexural strength, impact strength, etc. are improved, but melt viscosity also increases, and workability decreases. The melt viscosity of the thermoplastic resin can be expressed by the melt flow index (MI), the melt flow index (MI) according to the molecular weight of a representative thermoplastic resin, High Density Poly Ethylene (HDPE), and the Izod impact strength, which is a representative mechanical property value. (Izod Impact Strength) is shown in Table 1 below.

HDPE # Molecular weight (Mw) MI (g / 10min, 190 ℃) Izod Impact Strength (kg.cm/cm) One 190,300 0.02 Indestructible 2 147,900 0.84 Indestructible 3 134,200 1.00 10 4 68,800 8.5 6 5 56,400 20 3

Table 1 shows that the HDPE # 1 resin having a high molecular weight has excellent impact strength, but has a very low melt flow index (MI) of 0.02. On the contrary, the HDPE # 5 resin has a low impact strength of 3 and a very low impact strength of the molded article to which the resin is applied, but has a high melt flow index (MI) of 20, which is advantageous for impregnation during prepreg manufacture.

Again, referring to FIG. 3, the second thermoplastic resin films 44a and 44b are supplied by the second paper feeders 45a and 45b, and the second paper feeders 45a and 45b supply the raw material in the form of a film. It is a normal paper feeding device which supplies continuously. On the other hand, if necessary, the release materials 46a and 46b are supplied (laminated) to at least one surface of the second thermoplastic resin films 44a and 44b from the third feeders 47a and 47b. In the future, a phenomenon in which the molten second thermoplastic resin films 44a and 44b and the heating / pressing device 48 adhere to each other can be prevented. After the heating / pressing process, the release members 46a and 46b are recovered through the take-up rolls 49a and 49b. The temperature and pressure of the heating / pressing device 48 impregnate the reinforcing fibers 41 with the first thermoplastic resin films 42a and 42b, and the first thermoplastic resin films 42a and 42b and the first agent. As long as the 2 thermoplastic resin films 44a and 44b can be bonded together, it will not specifically limit, According to the kind and physical property of the said 1st thermoplastic resin films 42a and 42b and the 2nd thermoplastic resin films 44a and 44b suitably, Can be set.

As the heating / pressure device 48, a conventional heating / pressure device such as a roller, a double belt, a stationary press, or the like may be used. Figure 4 shows a conventional heating / pressurizing device that can be used in the present invention, a roller-type heating / pressurizing device (A), a double belt type heating / pressurizing device (B), heating / pressurization of the fixed press type The device C is shown. As shown in Fig. 4A, in the roller type heating / pressing device A, the reinforcing fibers 41 and the resin passing through a set of heating / pressing rollers 31a and 31b provided at the upper and lower portions thereof. The films 42a, 42b, 44a, 44b are heated / pressurized to impregnate the resin in the resin films 42a, 42b, 44a, 44b with the reinforcing fibers 41. In the roller type heating / pressing device A, only one set of rollers 31a and 31b may be used, but productivity may be improved by using a plurality of roller sets. As shown in FIG. 3B, the double belt type heating / pressing device B is a device which can continuously apply temperature and pressure by placing the continuous belts 32a and 32b made of metal on the upper and lower sides. . As shown in FIG. 3C, the fixed press type heating / pressing device C performs heating and pressurization through a module press 33a, 33b in the form of a block. The heating / pressing device C of the fixed press type may be composed of only one module press 33a, 33b, similarly to the roller-type heating / pressing device A, but using a plurality of module presses, And the impregnation efficiency can be improved. The roller type heating / pressing device (A) and the double belt type heating / pressing device (B) are mainly used for the continuous process, and the fixed press type heating / pressing device (C) is mainly used for the step process. Is used.

5 is a view showing the structure of a thermoplastic prepreg according to an embodiment of the present invention. As shown in FIG. 5, the thermoplastic prepreg according to an embodiment of the present invention may include a reinforcing fiber 41 in the form of a sheet and a melt flow index MI impregnated in the reinforcing fiber 41. The first thermoplastic resin films 42a and 42b and the second thermoplastic resin films 44a and 44b bonded to the first thermoplastic resin films 42a and 42b have a melt flow index MI of B or less. If necessary, as shown in FIG. 5, the reinforcing fibers 41 may be partially impregnated not only in the first thermoplastic films 42a and 42b but also in the second thermoplastic films 44a and 44b. . In this way, when the first thermoplastic resin films 42a and 42b having an advantageous impregnation in the reinforcing fibers 41 and the second resin films 44a and 44b having excellent physical properties are impregnated and bonded by heating / pressurizing, impregnation and mechanical properties It is possible to manufacture a thermoplastic prepreg 50 that satisfies all.

Hereinafter, the present invention will be described in more detail with reference to specific examples and comparative examples. The following examples are intended to illustrate the present invention in more detail, and the present invention is not limited by the following examples.

Example 1 Preparation of Thermoplastic Prepreg

One-way prepreg 135 was manufactured using the installation with the roller type heating / pressing apparatus 160 (refer FIG. 6A). Using an opening device 100, glass fibers (OCV SE4121, 2400 tex, 101) having a width of 30 cm and a fiber weight of 300 g / m ² per unit area were opened to open the first nip roll (140). ) Was added. 40 micrometer-thick low molecular weight HDPE (SK General Chemicals JK910, Mw: 56,400, MI: 20 in 190 degreeC) 1st paper feeding apparatuses 104a and 104b were thrown into the 1st paper feeding apparatuses 104a and 104b, Into the second paper feeders 132a and 132b, high molecular weight HDPE (SK General Chemicals 2800, Mw: 190,300, MI: 0.02 at 190 ° C) of the second thermoplastic resin films 131a and 131b was introduced into the second paper feeders 132a and 132b. The polyimide release films 105a and 105b having a 50 μm-thickness cross-sectional treatment were introduced into the third paper feeders 106a and 106b. The rollers of the heating / pressing device 160 of the roller type used three sets 107, 108, and 109, and the respective temperatures were 120 ° C. for the first roller 107, 190 ° C. for the second roller 108, and 3rd. The roller 109 was set to 190 ° C., and the pressure of the roller was set to 20 kg / cm of the first roller 107, 40 kg / cm of the second roller 108, and 40 kg / cm of the third roller 109. The production rate was 1.0 m / min (102). The release films 105a and 105b were recovered by take-up rolls 110a and 110b. The preparation conditions of the thermoplastic prepreg are summarized in Table 2, and the impact strengths are measured and shown in Table 3.

Comparative Example 1 Preparation of Thermoplastic Prepreg

As shown in FIG. 6B, a first thermoplastic resin film having a low molecular weight HDPE (SK General Chemicals JK910, Mw: 56,400, MI: 20 at 190 ° C.) having a thickness of 80 μm was provided with the first paper feeders 104a and 104b. A thermoplastic prepreg was produced in the same manner as in Example 1 except that 103a and 103b were added and second feeding devices 132a and 132b were not used. The preparation conditions of the thermoplastic prepreg are summarized in Table 2, and the impact strengths are measured and shown in Table 3.

Comparative Example 2 Preparation of Thermoplastic Prepreg

As shown in FIG. 6C, the first thermoplastic feeder 104a, 104b is a high-molecular weight HDPE having a thickness of 80 μm (SK General Chemicals 2800, Mw: 190,300, MI: 0.02 at 190 ° C.). A thermoplastic prepreg was produced in the same manner as in Example 1, except that (113a, 113b) was added and the second paper feeders 132a, 132b were not used. The preparation conditions of the thermoplastic prepreg are summarized in Table 2, and the impact strengths are measured and shown in Table 3.

input Production conditions First feed
Device 2nd paper feed
Device Third paper feed
Device 1st
roller Second
roller Third
roller production
speed Example 1 Low molecular weight
HDPE
(40 μm) High molecular weight
HDPE
(40 μm) Polyimide Release Film
(50 μm) 120 ℃,
20 kg / cm 190 ℃,
40 kg / cm 190 ℃,
40 kg / cm 1.0
(m / min) Comparative Example 1 Low molecular weight
HDPE
(80 μm) not used Polyimide Release Film
(50 μm) 120 ℃,
20 kg / cm 190 ℃,
40 kg / cm 190 ℃,
40 kg / cm 1.0
(m / min) Comparative Example 2 High molecular weight
HDPE
(80 μm) not used Polyimide Release Film
(50 μm) 120 ℃,
20 kg / cm 190 ℃,
40 kg / cm 190 ℃,
40 kg / cm 1.0
(m / min)

7 is a cross-sectional photograph and cross-sectional conceptual view of the thermoplastic prepreg produced according to the Examples and Comparative Examples of the present invention. As shown in FIG. 7, in the prepreg B of Comparative Example 1, the thermoplastic resin films 103a and 103b are uniformly impregnated in the reinforcing fiber 101, and the thermoplastic prepreg C of the Comparative Example 2 is The thermoplastic resin films 113a and 113b hardly penetrate the reinforcing fibers 101, are mainly distributed on the surface of the reinforcing fibers 101, and voids (gaps, 64) are formed between the reinforcing fibers 101, and resins It can be seen that the impregnation is insufficient. On the other hand, the thermoplastic prepreg A of Example 1 uses the first thermoplastic resin films 130a and 130b and the second thermoplastic resin films 131a and 131b simultaneously, and the first resin films 130a and 130b are used. It can be seen that the reinforcing fibers 101 are sufficiently impregnated, and the second resin films 131a and 131b are positioned in a layer on the outside.

Psalter Izod impact strength (J / m) Example 1 1800 Comparative Example 1 1000 Comparative Example 2 2300

As shown in Table 3, the prepreg of Comparative Example 1 has a low impact strength using a relatively low molecular weight resin, the prepreg of Comparative Example 2 used a high molecular weight resin having excellent physical properties, but due to poor impregnation Due to the mechanical properties could not be maximized. On the other hand, the thermoplastic prepreg of Example 1 has a high impact strength in combination with impregnation and mechanical properties.

Example 2 Preparation of PC / PET Hybrid Thermoplastic Prepreg

As the heating / pressure device 160, a double belt heating / pressure device (divided into three sections) was sequentially set to a temperature of 200 ° C. in the first part, 260 ° C. in the second part, and 280 ° C. in the third part. Pressure is 20 kg / cm), and as the reinforcing fiber 101, a woven 3K carbon fiber plain fabric (modern fiber product C120, fiber weight per unit area: 200 g / m ² ), As the first thermoplastic resin films 130a and 130b, a 40 μm-thick PET resin film (SKC SKYroll) was used, and as the second thermoplastic resin films 131a and 131b, a 40 μm thick PC resin film (ione film) Product IPC-40A), and the remaining conditions were the same as in Example 1, to prepare a thermoplastic prepreg. A cross-sectional photograph of the prepared thermoplastic prepreg is shown in FIG. 8. As shown in FIG. 8, a tow 72 formed of a bundle of carbon fibers 150 constitutes a fabric, and PET resin films 130a and 130b having a low melt viscosity are impregnated between the tows 72. PC resin films 131a and 131b having excellent mechanical properties are bonded to the outside. Therefore, the thermoplastic prepreg of the present invention is a PC resin film (131a, 131b) is difficult to be impregnated, while the PET resin film (130a, 130b) is well impregnated in the reinforcing fiber 150, even at a low processing temperature It can be seen that the mechanical properties of can be utilized simultaneously.

Claims (8)

Supplying a first thermoplastic resin film to at least one side of the reinforcing fibers in sheet form;
Supplying a second thermoplastic resin film on the first thermoplastic resin film; And
Heating and pressurizing the first thermoplastic resin film and the second thermoplastic resin film to impregnate the first thermoplastic resin film with the reinforcing fiber, and to bond the first thermoplastic resin film and the second thermoplastic resin film together. Including;
In the heating and pressing step, the melt flow index (MI) of the first thermoplastic resin film is greater than the melt flow index (MI) of the second thermoplastic resin film, thermoplastic prepreg manufacturing method. The melt flow index (MI) ratio of the first thermoplastic resin film to the melt flow index (MI) of the second thermoplastic resin film is 1.01 times or more, wherein the melt flow index (MI) is ASTM. Measured according to D1238, the measurement temperature is the temperature of the heating and pressing step of the first thermoplastic resin film and the second thermoplastic resin film, the measurement load is 2160 g, the resin dissolution time is 10 minutes, and the measurement unit is gram (g / 10 minutes), the method of producing a thermoplastic prepreg. The method of claim 1, wherein the melt flow index (MI) of the first thermoplastic resin film is 5 or more, the melt flow index (MI) of the second thermoplastic resin film is less than 5, wherein the melt flow index (MI) Is measured according to ASTM D1238, and the measurement temperature is the temperature of the heating and pressing step of the first thermoplastic resin film and the second thermoplastic resin film, the measurement load is 2160 g, the resin dissolution time is 10 minutes, and the measurement unit is gram ( g / 10 min). The method of claim 1, wherein the first thermoplastic resin film and the second thermoplastic resin film is polypropylene, polyethylene, polyamide, polystyrene, polyester, polycarbonate, thermoplastic polyurethane, polyacetal, polymethyl methacrylate, polyethylene terephthalate And polybutylene terephthalate, ABS resin, polyetherimide, polyetheretherketone, polyphenylene sulfide and polylactic acid. Reinforcing fibers in the form of sheets;
A first thermoplastic resin film impregnated in the reinforcing fiber; And
A second thermoplastic resin film bonded to the first thermoplastic resin film,
The melt flow index (MI) of the first thermoplastic resin film is greater than the melt flow index (MI) of the second thermoplastic resin film, the thermoplastic prepreg. The thermoplastic prepreg according to claim 5, wherein the second thermoplastic resin film is bonded to both surfaces of the first thermoplastic resin film. The thermoplastic prepreg according to claim 5, wherein the first thermoplastic resin film and the second thermoplastic resin film are made of the same type of resin. The thermoplastic prepreg of claim 5, wherein the reinforcing fiber is selected from the group consisting of carbon fiber, glass fiber, aramid fiber, basalt fiber, and boron fiber.

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