JP6021343B2 - Impregnated yarn cloth and method for producing impregnated yarn cloth - Google Patents

Description

  The present invention relates to an impregnated yarn cloth using an impregnated yarn as a woven fabric, and a method for producing the impregnated yarn cloth.

  In general, a sheet-like impregnated cloth such as a prepreg is used as a base material for molding a fiber-reinforced resin molded product. This impregnated fabric is a fabric obtained by knitting a fiber bundle in advance, and the surface of the substrate is coated with a thermoplastic resin. When this impregnated fabric is heated, the thermoplastic resin that coats the surface of the base material is dissolved, and the base material that has been restrained by the thermoplastic resin can be deformed (modeled). And if a thermoplastic resin is cooled and solidified after shape | molding an impregnation cloth into a desired shape, a sheet-like impregnation cloth can be shape | molded into a molded object.

By the way, in recent years, there has been an increase in the number of cases where a molded body having a complicated shape such as an automobile interior material or body is molded, and the impregnated fabric is required to have high formability so as to follow such a complicated shape. .
However, if the fiber bundle is first knitted and then coated with a thermoplastic resin as in the above-described impregnated cloth, the substrate becomes difficult to deform unless the coated thermoplastic resin is plasticized. As a result, it becomes difficult to transform the impregnated cloth into a molded body having an arbitrary shape.

  Therefore, in Patent Document 1, before knitting a fiber bundle into a cloth state, each fiber bundle is preliminarily coated with a thermoplastic resin to form an impregnated yarn, and the impregnated yarn is knitted to form an impregnated yarn cloth. Is disclosed.

Japanese Patent Laid-Open No. 04-185313

By the way, the impregnated yarn cloth obtained by the method of Patent Document 1 can be easily deformed as compared with the above-described impregnated fabric because each of the impregnated yarns can move relatively freely, and the formability is good.
However, each of the impregnated yarns constituting the impregnated yarn fabric is obtained by coating a fiber bundle obtained by bundling single fibers aligned in one direction with a thermoplastic resin, which is very hard. It is rigid and cannot be bent freely. That is, the impregnated yarn fabric formed by weaving such an impregnated impregnated yarn is inevitably large in order to avoid breakage of the single fiber. As a result, the density of fiber bundles in the molded body may be insufficient, and it may be difficult to obtain a molded body having high strength.

Also, if the impregnated yarn is forcibly bent or bent in order to reduce the mesh opening, the impregnated yarn may be excessively wrinkled or the thermoplastic resin may be peeled off from the surface of the fiber bundle. On the contrary, the strength of the impregnated yarn cloth or the molded body may be lowered.
Furthermore, the knitting work using the impregnated yarn which is difficult to bend is very troublesome, and it is often difficult to improve the productivity of the impregnated yarn cloth.

  The present invention has been made in view of the above-mentioned problems, and can obtain a molded body having a small shape of the impregnated yarn and excellent in strength with high productivity while having good formability. An object of the present invention is to provide a method for producing an impregnated yarn cloth and an impregnated yarn cloth.

In order to solve the above problems, the method for producing an impregnated yarn fabric of the present invention takes the following technical means.
That is, according to the method for producing an impregnated yarn fabric of the present invention, a twist of 20 times / m or more and 700 times / m or less is added to or added to the fiber bundle, and the fiber bundle is stored in a molten state. The impregnated yarn is formed by impregnating the formed resin tank, and the formed impregnated yarn is knitted to obtain an impregnated yarn cloth.

Preferably, the impregnated yarn is knitted so that the mesh opening is 0 mm or more and 10 mm or less.
On the other hand, the impregnated yarn cloth of the present invention is characterized in that fiber bundles coated with a thermoplastic resin are knitted together, and the fiber bundles are twisted at 20 times / m or more and 700 times / m or less. It is what.

Preferably, the mesh is knitted so that the mesh opening is 0 mm or more and 10 mm or less.
Further, the most preferable embodiment of the method for producing an impregnated yarn fabric according to the present invention is to add a twist of more than 30 times / m and not more than 70 times / m to the fiber bundle, and then heat the fiber bundle. By impregnating a resin tank in which a plastic resin is stored in a molten state, the surface of the fiber bundle to which a twist of more than 30 times / m and 70 times / m or less is applied is coated with the thermoplastic resin and hardened. Forming an impregnated yarn, and knitting the impregnated yarn to obtain an impregnated yarn fabric, wherein the fiber bundles coated on the surface of the thermoplastic resin are woven together as latitude and longitude lines. Features.
Furthermore, the most preferable form of the impregnated yarn fabric according to the present invention is that fiber bundles coated with a thermoplastic resin are knitted together as latitude and longitude lines, and the fiber bundle is more than 30 times / m and 70 times. / m have been twisted or less, the thermoplastic resin is characterized by being hardened by coating a 30 times / more than m, and 70 turns / m surface of the fiber bundle of twisted below.

  According to the method for producing an impregnated yarn fabric and the impregnated yarn fabric of the present invention, it is possible to obtain a molded product having fine fiber bundles and excellent strength in high productivity while having good formability. it can.

(A) is a plan view of the impregnated yarn cloth of the present invention, (b) is a cross-sectional view taken along line AA of FIG. 1 (a), and (c) is formed from the impregnated yarn cloth of FIG. 1 (a). It is a top view of the formed object. It is a flowchart which shows the manufacturing method of the impregnation yarn cloth and molded object of this invention. It is a perspective view which shows the manufacturing apparatus used for manufacture of an impregnation yarn cloth. It is a figure which shows the change of the tensile strength with respect to the frequency | count of twist of an impregnation thread | yarn, (a) is a case where a fiber bundle is a glass fiber, (b) is a case where a fiber bundle is a carbon fiber.

An embodiment of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.
As shown in FIGS. 1 (a) to 1 (c), an impregnated yarn fabric 1 according to an embodiment of the present invention is an impregnated yarn comprising a fiber bundle 2 (reinforced fiber bundle) having a surface coated with a thermoplastic resin 5. 3 is formed by knitting a plurality of impregnated yarns 3. That is, the impregnated yarn cloth 1 of the present invention is obtained by weaving the impregnated yarn 3 that is a resin composite material.

Next, the impregnated yarn 3 constituting the impregnated yarn fabric 1 of the present invention and the woven state of the impregnated yarn 3 will be described in detail below.
The impregnated yarn 3 constituting the impregnated yarn fabric 1 includes a fiber bundle 2 that enhances mechanical properties (such as tensile strength) of the molded body 4 and a thermoplastic material that covers the surface (periphery) of the fiber bundle 2 in the longitudinal direction. And resin 5.

The fiber bundle 2 is a bundle of single fibers, which will be described later, and the single fibers are formed of fibers that can reinforce the thermoplastic resin 5 that is a matrix. For example, glass fiber, carbon fiber, or fiber such as aramid can be used for the fiber bundle 2.
The fiber bundle 2 is a bundle of the above-described single fibers of 500 tex or more and 15000 tex or less (JIS L 0101), and the outer diameter (diameter) per fiber bundle 2 is 0.3 mmφ or more and 3.0 mmφ or less. Has been.

  The thermoplastic resin 5 covers the surface of the fiber bundle 2 of the impregnated yarn 3. The thermoplastic resin 5 also functions as a binder that is interposed between the fiber bundles 2 knitted together when the molded body 4 is molded, and binds them together. Specifically, as the thermoplastic resin 5, a polyolefin resin such as polypropylene or polyethylene can be used. Besides the polyolefin resin, a polyamide resin such as nylon, PET, PBT, PEI, PEEK, etc. Resin can be used.

Next, how to weave the impregnated yarn 3 will be described.
When the above-described impregnated yarn 3 is knitted, it may be knitted or woven. For example, when the impregnated yarn 3 is knitted, a knitting method such as flat knitting, knitting, rubber knitting, chain knitting, or garter knitting can be employed. Further, when weaving the impregnated yarn 3, a weaving method such as oblique weaving or satin weaving can be employed in addition to the plain weaving as shown in FIG. This is because the formability of the impregnated yarn fabric 1 can be improved by changing the knitting method in the above-described types.

By the way, in the conventional impregnated yarn 3, each impregnated yarn 3 was formed by covering and solidifying the periphery of the single fiber aligned along one direction with the thermoplastic resin 5. The impregnated yarn 3 obtained by such a method is rigid and inflexible, and the mesh opening becomes large even when knitted, so that there is a possibility that sufficient strength as the impregnated yarn fabric 1 cannot be obtained. Further, since the impregnated yarn 3 obtained by the conventional method is difficult to bend during knitting, it may be difficult to efficiently produce the impregnated yarn fabric 1 (see the description of the problem to be solved by the invention).

  Therefore, in the impregnated yarn fabric 1 of the present invention, a plurality of single fibers are twisted so that the number of twists is 20 times / m or more and 700 times / m or less, preferably 20 times / m or more and 200 times / m or less. The fiber bundle 2 formed in this way is used for the impregnated yarn 3. Thus, when the number of twists of the fiber bundle 2 is 20 times / m or more and 700 times / m or less, preferably 20 times / m or more and 200 times / m or less, the flexibility of each impregnated yarn 3 Therefore, the opening when knitted into the impregnated yarn cloth 1 can be reduced, and the mechanical strength (tensile strength) of the impregnated yarn cloth 1 can be improved as compared with the conventional one. Further, if the flexibility of the impregnated yarn 3 is improved, the impregnated yarn 3 can be easily bent during knitting, and the productivity when knitting the impregnated yarn fabric 1 can be increased.

  Specifically, in the impregnated yarn 3 of the present embodiment, the fiber bundle 2 is twisted 20 times / m or more and 700 times / m or less (in other words, 20 times / m or more and / or 700 times / m or less). In addition, it is twisted so as to be 20 times / m or more and 200 times / m or less (in other words, 20 times / m or more and / or 200 times / m or less). The twisting direction of the fiber bundle 2 may be right-handed or left-handed. The number of fiber bundles 2 used for one impregnated yarn 3 is preferably 2 or more and 10 or less.

Further, the impregnated yarn cloth 1 of the present invention is knitted using the impregnated yarn 3 having the number of twists as described above, so that the mesh opening is knitted to 0 mm or more and 10 mm or less. In the case of such an impregnated yarn cloth 1 with openings, the molded body 4 having excellent mechanical strength can be formed by supplying the fiber bundle 2 with a sufficient density into the molded body 4.
Next, a method for actually manufacturing the above-described impregnated yarn cloth 1, in other words, a method for manufacturing the impregnated yarn cloth 1 of the present invention will be described.

As shown in the flowchart of FIG. 2, the method for producing the impregnated yarn fabric 1 of the present invention involves impregnating the fiber bundle 2 in a resin tank (impregnation portion 12) in which the thermoplastic resin 5 is stored in a molten state. A first step 7 for forming an impregnated yarn 3 in which a twist is added to 2 and a second step 8 for knitting the impregnated yarn 3 formed in the first step 7 to obtain an impregnated yarn fabric 1 of a resin composite material. I have.
Prior to explaining the contents of the first step 7, the manufacturing apparatus 9 used in the first step 7 will be described first.

As shown in FIG. 3, the manufacturing apparatus 9 includes a hopper 10 that supplies pellets of the thermoplastic resin 5. The pellets of the thermoplastic resin 5 supplied from the hopper 10 are kneaded in a kneading section 11 provided adjacent to the hopper 10. The thermoplastic resin 5 plasticized in the kneading part 11 is sent to the impregnation part 12 and stored in the impregnation part 12.
The impregnated portion 12 is formed in a long bottomed cylindrical shape having an axial center in the vertical direction so that the plasticized thermoplastic resin 5 can be stored, and is open upward. A plurality of fiber bundles 2 unwound from a bobbin disposed on the side of the impregnation portion 12 are fed into the impregnation portion 12 from the upper opening.

The plurality of fiber bundles 2 are respectively supplied from bobbins provided in the same number corresponding to the number of the fiber bundles 2 and are impregnated through the upper guide roll 14 after being preheated by the preheater 13. It is sent to the part 12.
A die nozzle 15 is provided below the impregnation portion 12 to take out the fiber bundle 2 fed from the upper opening to the outside of the impregnation portion 12, and the thermoplastic resin 5 is applied to the surface of the fiber bundle 2 using the die nozzle 15. Only a predetermined thickness can be covered. Further, a lower guide roll (not shown) that transports the fiber bundle 2 in a state of being wound around the melted thermoplastic resin 5 in the impregnated portion 12 and between the upper opening and the die nozzle 15. It is deployed in an impregnated state.

  A water tank 16 is provided on the downstream side of the impregnation portion 12 to promote cooling and curing of the thermoplastic resin 5 that covers the surface of the fiber bundle 2. Further, a take-up machine 17 (twisting roller device) for twisting the fiber bundle 2 cooled in the water tank 16 is provided on the downstream side of the water tank 16. The take-up machine 17 winds the fiber bundle 2 with a roller (uncoiler) around an axis that faces in a direction orthogonal to the transfer direction of the fiber bundle 2, and rotates the roller around an axis that faces the transfer direction of the fiber bundle 2. It is set as the structure rotated so that it may twist. When the fiber bundle 2 is wound up by such a take-up machine 17, as described above, a twist of 20 times / m or more and 700 times / m or less, preferably 20 times / m or more and 200 times / m or less is applied to the fiber bundle 2. It is possible to form the impregnated yarn 3 while being applied.

In the second step 8, the impregnated yarn fabric 1 is formed by weaving the impregnated yarn 3 formed in the first step 7. A known knitting machine or weaving machine can be used for the second step 8, and the impregnated yarn cloth 1 is formed by knitting the impregnated yarn 3 with a desired knitting method or weaving method using the knitting machine or the weaving machine. . In addition, about the knitting machine and weaving machine used for the 2nd process 8, illustration is abbreviate | omitted.
Thus, if the impregnated yarn cloth 1 formed by knitting in the second step 8 is hot-pressed along the desired shape, the molded body 4 is formed from the impregnated yarn cloth 1 as shown by a dotted line in FIG. Is possible.

  In the impregnated yarn cloth 1 of the present invention, each fiber bundle 2 constituting the impregnated yarn cloth 1 is 20 times / m or more and 700 times / m or less, preferably 20 times / m or more and 200 times / m. It is twisted together below. Therefore, the flexibility of the fiber bundle 2 is higher than that aligned along one direction, and even when the impregnated yarn 3 is used, it can be freely bent or bent. Naturally, in the impregnated yarn cloth 1 knitted from the flexible impregnated yarn 3, the mesh opening can be made small, and the mechanical strength (tensile strength) of the impregnated yarn cloth 1 is increased by closing the eyes of the impregnated yarn 3. This can be improved from the conventional one.

Further, if the flexibility of the impregnated yarn 3 is improved, the impregnated yarn 3 can be easily bent during knitting, and the productivity when knitting the impregnated yarn fabric 1 can be increased.
Further, the impregnated yarn 3 having such a twist is excellent in mechanical strength such as tensile strength, and the strength of the impregnated yarn cloth 1 itself is increased. Therefore, if the impregnated yarn cloth 1 of the present invention is used, it is possible to obtain a molded body 4 in which the fiber bundles 2 are densely arranged and excellent in strength as shown in FIG.

Next, the effects of the impregnated yarn fabric 1 of the present invention will be described in more detail using examples.
First, in order to examine the influence of the number of twists of the fiber bundle 2 on the tensile strength of the impregnated yarn 3, Examples 1 to 3 shown below were prepared.
Specifically, the fiber bundle 2 used for the impregnated yarn fabric 1 of Example 1 is a bundle of single fibers of glass fiber so as to have a count of 4620 tex, and its outer diameter is set to 3.0 mmφ. Moreover, the fiber bundle 2 used for the impregnated yarn cloth 1 of Example 2 is a bundle of single fibers of glass fiber so as to have a count of 575 tex, and its outer diameter is 1.05 mmφ. Furthermore, the fiber bundle 2 used for the impregnated yarn fabric 1 of Example 3 is a bundle of carbon fibers monofilaments so as to have a count of 15000 tex, and its outer diameter is 1.7 mmφ.

  The fiber bundle 2 of Examples 1 to 3 is coated with the thermoplastic resin 5 (polypropylene) while changing the number of twists in the take-up machine 17 in the range of 0 to 120 times / m, and fibers An impregnated yarn 3 containing 25-30 vol% of the bundle 2 was produced. The impregnated yarn 3 thus obtained was measured for tensile strength using a tensile tester. The measurement results are shown in FIGS. 4 (a) and 4 (b).

  Looking at the results of Example 1 indicated by black diamonds in FIG. 4 (a), when the number of twists in the take-up device increases from 0 times / m to 25 times / m, the tensile strength also increases with this increase. growing. And comparatively big tensile strength is maintained in the range whose twist number is 25-70 times / m. However, if the number of twists in the take-up device exceeds 70 turns / m, the tensile strength rapidly decreases against the increase in the number of twists.

  On the other hand, even in the results of Example 2 shown by the black squares in FIG. 4A, a relatively large tensile strength is maintained in the range of 10 to 80 turns / m. If it is smaller or larger than the range, the tensile strength decreases. In addition, the same tendency is obtained in the result of Example 3 indicated by black circles in FIG. 4B, and a relatively large tensile strength is maintained in the range of 18 to 60 turns / m. ing.

From this, the twist number of the fiber bundle 2 in the impregnated yarn 3 for any of Examples 1 to 3 is
If the value is 20 to 50 times / m, it is judged that the tensile strength can be increased.
On the other hand, the bending radius was measured for the impregnated yarn 3 of Examples 1 to 3 in which the number of twists of the fiber bundle 2 was 30 times / m. In this bending radius measurement, for example, the impregnated yarn is bent with respect to cylinders having different curvature radii, and the curvature radius that can be bent without damage is measured. This radius of curvature was taken as the bending radius. Further, as a comparative example, impregnated yarn 3 (twist number = 0 times / m) in which a thermoplastic resin 5 was coated around a fiber bundle 2 in which single fibers were arranged in parallel without being twisted was used. Table 1 shows the results of measuring the bending radii for the impregnated yarns 3 of Examples 1 to 3 and Comparative Example.

As is apparent from Table 1, it can be seen that “with twist” has a smaller bending radius to at least about 1/3 than “without twist”, making it easier to bend. From this, it is determined that the impregnated yarn 3 with “twisted” has better formability than “without twist”.
It should be noted that matters not explicitly disclosed in the embodiment disclosed this time, such as operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component, deviate from the range normally practiced by those skilled in the art. However, matters that can be easily assumed by those skilled in the art are employed.

DESCRIPTION OF SYMBOLS 1 Impregnation yarn cloth 2 Fiber bundle 3 Impregnation thread 4 Molded body 5 Thermoplastic resin 7 1st process 8 2nd process 9 Manufacturing apparatus 10 Hopper 11 Kneading part 12 Impregnation part 13 Preheater 14 Upper guide roll 15 Die nozzle 16 Water tank 17 Take-out machine

Claims (4)

By adding or adding a twist of more than 30 times / m and not more than 70 times / m to the fiber bundle, and impregnating the fiber bundle with a resin tank in which the thermoplastic resin is stored in a molten state, The surface of the fiber bundle to which a twist of more than 70 times / m and less than 70 times / m is applied is coated with a thermoplastic resin to form an impregnated yarn, and the impregnated yarn thus formed is knitted and woven. To get a cloth,
A method for producing an impregnated yarn fabric, characterized in that a fiber bundle having a surface coated with the thermoplastic resin is knitted together as latitude and longitude lines.   The method for producing an impregnated yarn fabric according to claim 1, wherein the impregnated yarn is knitted so that the mesh opening is 0 mm or more and 10 mm or less. Fiber bundles coated with a thermoplastic resin on the surface are knitted together as wefts and warps, and the fiber bundles are twisted at more than 30 times / m and less than 70 times / m,
An impregnated yarn cloth characterized in that the thermoplastic resin is coated and hardened on the surface of a fiber bundle twisted more than 30 times / m and less than 70 times / m.   4. The impregnated yarn fabric according to claim 3, wherein the mesh opening is knitted to be 0 mm or more and 10 mm or less.