JP2024031860A - Rod-shaped composite body made of fiber-reinforced thermoplastic resin, and manufacturing method of the same - Google Patents

Abstract

To provide a rod-shaped composite body made of a fiber-reinforced thermoplastic resin which is excellent in bending strength, and a manufacturing method of the same.SOLUTION: There are provided a rod-shaped composite body made of a fiber-reinforced thermoplastic resin which includes at least a reinforcement layer formed of a fiber bundle for reinforcement impregnated with a thermoplastic resin, and one or two or more coating layers for coating the outermost side of the reinforcement layer with a thermoplastic resin, wherein the reinforcement layer is in a state where twisting is applied, and a volume content ratio of the fiber for reinforcement is 20% or more and 80% or less with respect to the whole reinforcement layer; and a manufacturing method of the same.SELECTED DRAWING: Figure 1

Description

The present invention relates to a fiber-reinforced thermoplastic resin rod-shaped composite and a method for manufacturing the same. More specifically, the present invention relates to a fiber-reinforced thermoplastic resin rod-shaped composite having excellent bending strength and a method for manufacturing the same.

Articles made of fiber-reinforced thermosetting resin (FRP), which is made by binding reinforcing fibers with synthetic resin, are both strong and lightweight, so they are used as an alternative to metal articles in automobile parts, electronic parts, and agricultural and forestry materials. It is used in a wide range of fields such as construction materials, furniture, etc. One of the products using this FRP technology, pipes, rods, linear objects, etc. that use long fiber bundles such as glass roving as reinforcing fibers and thermosetting resin as a matrix have been used in various industrial fields for a long time. ing.

For example, Patent Document 1 discloses that a long reinforcing fiber bundle is impregnated with a molten resin and rotated around its axis by a twisting machine to give twist to the reinforcing fiber bundle. Disclosed is a method for producing characteristic fiber-reinforced resin strands.

Furthermore, Patent Document 2 discloses that a plurality of reinforcing fiber bundles are twisted together and pulled out of a melted thermoplastic resin to form a strand in which the thermoplastic resin is coated around the reinforcing fibers, and the strand is A method for producing long fiber-reinforced thermoplastic resin pellets obtained by cutting into predetermined lengths to obtain pellets, the method comprising: adjusting the melt viscosity of the thermoplastic resin to a melt flow rate of 500 to 1500 g/10 min, and drawing the strands in the drawing direction. A method for producing long fiber-reinforced thermoplastic resin pellets is disclosed, which is characterized in that the strands are pulled out with the twist angle θ of the reinforcing fiber bundle set to 0°<θ≦50°.

Japanese Patent Application Publication No. 05-169445 JP2011-62971A

However, fiber-reinforced thermoplastic resin rod-shaped composites manufactured by conventional manufacturing methods have low bending strength, and it is necessary to further improve the bending strength.

In view of these circumstances, the main object of the present invention is to provide a fiber-reinforced thermoplastic resin rod-shaped composite having excellent bending strength and a method for manufacturing the same.

As a result of intensive experimental studies by the inventors of the present application, by focusing on the structure of the fiber-reinforced thermoplastic resin rod-shaped composite, we found a fiber-reinforced thermoplastic resin rod-shaped composite with excellent bending strength and its production. They discovered a method and completed the present invention.

That is, in the present invention, first, a reinforcing layer formed of a reinforcing fiber bundle impregnated with a thermoplastic resin, and one or more coating layers covering the outermost side of the reinforcing layer with a thermoplastic resin. At least the reinforcing layer is in a twisted state, and the volume content ratio of the reinforcing fibers is 20% or more and 80% or less with respect to the entire reinforcing layer. Provide complexes.
In the present invention, the thermoplastic resin covering the outermost side has a melting start temperature lower than or equal to the melting start temperature of the thermoplastic resin impregnated into the reinforcing fiber bundle, or the thermoplastic resin covering the outermost side has a melting start temperature of , 200°C or lower.

Further, the present invention includes at least a reinforcing layer formed of a reinforcing fiber bundle impregnated with a thermoplastic resin, and one or more coating layers covering the outermost side of the reinforcing layer with a thermoplastic resin. , the reinforcing layer is in a twisted state, and the volume content ratio of the reinforcing fibers is 20% or more and 80% or less with respect to the entire reinforcing layer, a rod-shaped composite made of fiber-reinforced thermoplastic resin. The manufacturing method includes a step A of impregnating a reinforcing fiber bundle with a thermoplastic resin, and then imparting a twist to the reinforcing fiber bundle impregnated with the thermoplastic resin; The present invention also provides a method for manufacturing a fiber-reinforced thermoplastic resin rod-shaped composite body, which comprises at least performing step B of cooling a reinforcing fiber bundle impregnated with a thermoplastic resin to form a reinforcing layer.

According to the present invention, it is possible to provide a fiber-reinforced thermoplastic resin rod-shaped composite having excellent bending strength and a method for manufacturing the same.
Note that the effects described here are not necessarily limited, and may be any of the effects described in this specification.

1 is a diagram schematically showing the structure of a fiber-reinforced thermoplastic resin rod-shaped composite body 1 according to the present invention. 1 is a diagram schematically showing an outline of a manufacturing method according to the present invention. This is a photograph substituted for a drawing showing a circular metal object used in a heat workability confirmation test. 3 is a diagram schematically showing an outline of a manufacturing method of Comparative Example 3. FIG.

Hereinafter, preferred embodiments for carrying out the present invention will be described in detail with reference to the drawings.
Note that the embodiment described below is an example of a typical embodiment of the present invention, and the scope of the present invention should not be interpreted narrowly thereby.

1. Fiber-reinforced thermoplastic resin rod-shaped composite 1
FIG. 1 is a diagram schematically showing the structure of a fiber-reinforced thermoplastic resin rod-shaped composite 1 according to the present invention. A fiber-reinforced thermoplastic resin rod-shaped composite 1 according to the present invention (hereinafter also simply referred to as "composite 1 according to the present invention") includes a reinforcing layer 11 and one or more coating layers 12. At least be prepared.

The composite body 1 according to the present invention is rod-shaped, and the term "rod-shaped" here specifically refers to a shape whose cross section is circular or flat, such as an ellipse.

Since the composite body 1 according to the present invention has the above structure and has excellent bending strength, it is being used more than ever as a material to replace metal articles in automobile parts, electronic parts, agricultural and forestry materials, and construction materials. It is expected that it will be used in a wide range of fields such as furniture. Each layer will be explained in detail below.

(1) Reinforcement layer 11
As shown in FIG. 1, the reinforcing layer 11 is a layer formed of reinforcing fiber bundles 112 impregnated with a thermoplastic resin 111. A reinforcing fiber impregnated with a thermoplastic resin is generally referred to as a fiber reinforced thermoplastic resin (FRTP).

<Reinforcing fiber bundle 112>
The reinforcing fiber bundle 112 is preferably a base material in the form of, for example, a continuous long fiber bundle or a fiber braid (for example, a woven fabric, a knitted fabric, a braided fabric, etc.). By using these materials, continuous impregnation and continuous formation of the coating layer can be ensured, and it becomes possible to manufacture the fiber-reinforced thermoplastic resin rod-shaped composite 1 having the coating layer with excellent productivity.

Examples of the fibers constituting the reinforcing fiber bundle 112 include organic fibers such as olefin fibers, aramid fibers, and liquid crystal polyester (LCP) fibers; glass fibers; inorganic fibers such as carbon fibers; ceramic fibers such as tyranno fibers; Although fibers, metal fibers such as copper and stainless steel; amorphous fibers, etc. can be used, in the present invention, among these, it is particularly preferable to use glass fibers and/or carbon fibers. In addition, in the present invention, these mixed fabrics can also be used.

As the glass fiber, for example, long fibers such as glass fiber monofilament, glass fiber strand, glass fiber roving, and glass fiber yarn can be used, but in the present invention, among these, in particular, glass fiber roving and/or glass fiber yarn can be used. It is preferable to use Furthermore, glass fiber braided materials such as glass fiber fabrics, glass fiber braids, and glass fiber knitted materials are also applicable. Note that the glass fiber may be surface-treated with a surface treatment agent such as an epoxy silane coupling agent or an acrylic silane coupling agent. Further, examples of the glass composition of the glass fiber include E glass, S glass, and C glass, and among these, E glass is particularly preferred in the present invention. Further, the cross section of the glass fiber monofilament may be circular or flat, such as an ellipse.

The glass fiber roving is preferably a glass fiber bundle in which 100 to 5,000 glass fiber monofilaments with a diameter of 3 to 100 μm are bundled, and 3 to 500 glass fibers are further bundled.

There are three types of carbon fiber: ``pitch type'' made from coal tar pitch or petroleum pitch, ``PAN type'' made from polyacrylonitrile, and ``rayon type'' made from cellulose fiber. Any carbon fiber can be used in the invention.

The reinforcing fiber bundle 112 can be prepared by weaving, braiding, or knitting into a desired length using well-known methods, or by winding a long one into a roll, as necessary. You can take it and use it. Further, the reinforcing fiber bundle 112 may be heated in order to improve the impregnation of the reinforcing fibers with the resin or to remove moisture from the reinforcing fibers.

The volume content ratio of the reinforcing fibers (bundle) 112 is preferably 20% or more and 80% or less, more preferably 40% or more and 60% or less, based on the entire reinforcing layer 11. When the volume content ratio is lower than 20%, the reinforcing effect of the reinforcing fibers becomes low. Conversely, if the volume content ratio exceeds 80%, the bending strength will be adversely affected due to the small amount of resin.

<Thermoplastic resin 111 used for reinforcing layer 11>
Examples of the thermoplastic resin 111 as a matrix resin used in the reinforcing layer 11 include polyolefin resins such as polypropylene (PP), polyethylene (PE), and polyisobutylene (PIB); polyethylene terephthalate (PET), polybutylene terephthalate ( Polyester resins such as PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PENp), and liquid crystal polyester (LCP); polystyrene (PS), acrylonitrile-styrene resin (AS), acrylonitrile-butadiene-styrene resin (ABS) ), styrenic resins such as acrylonitrile-acrylic-styrene resin (AAS), acrylonitrile-ethylene-propylene rubber-styrene (AES); urethane resins, and the like. In addition, polyvinyl alcohol (PVA), polyoxymethylene (POM), polyamide (PA), polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), polyphenylene Ether (PPE), modified PPE, polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polysulfone (PSU), modified PSU, polyethersulfone (PES), polyketone (PK), polyetherketone ( PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyarylate (PAR), polyethernitrile (PEN), and the like.

In the present invention, it is particularly preferable to use one or more selected from the group consisting of polycarbonate, acrylonitrile-styrene resin, polypropylene, and polyvinyl alcohol, and more preferably polycarbonate and/or acrylonitrile-styrene resin. preferable.

<Twisting in reinforcing layer 11>
In the present invention, the reinforcing layer 11 is in a twisted state. The direction of twist may be either unidirectional twist (S twist or Z twist) or SZ twist. The twist may be applied at any step between the outlet of the impregnating tank and the coating step, but it can be applied, for example, at step A in the manufacturing method according to the present invention, which will be described later. Furthermore, the method for imparting twist is not particularly limited.

When twisting is applied, the twist pitch width is preferably 800 mm or less, more preferably 500 mm or less, even more preferably 300 mm or less, and particularly preferably 200 mm or less. If the twist pitch width is larger than 800 mm, the softening of the impregnated thermoplastic resin causes buckling or whitening due to the difference in tension between the outer circumferential side and the inner circumferential side of the FRTP rod reinforcing fiber when bent.

(2) Covering layer 12
The covering layer 12 is one or more layers that cover the outermost part of the reinforcing layer 11 with a thermoplastic resin. In addition, although FIG. 1 depicts the case where the covering layer 12 is one layer, in this invention, the covering layer 12 may be two or more layers. An example of a structure in which there are two or more coating layers 12 is a structure in which part or all of the first coating layer 12 covering the reinforcing layer 11 is sequentially covered with a second or more coating layer 12.

<Thermoplastic resin used for coating layer 12>
Examples of the thermoplastic resin used in the coating layer 12 include polyolefin resins such as polypropylene (PP), polyethylene (PE), and polyisobutylene (PIB); polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polytriester. Polyester resins such as methylene terephthalate (PTT), polyethylene naphthalate (PENp), and liquid crystal polyester (LCP); polystyrene (PS), acrylonitrile-styrene resin (AS), acrylonitrile-butadiene-styrene resin (ABS), acrylonitrile-acrylic - Styrenic resins such as styrene resin (AAS) and acrylonitrile/ethylene propylene rubber/styrene (AES); urethane resins and the like. In addition, polyvinyl alcohol (PVA), polyoxymethylene (POM), polyamide (PA), polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), polyphenylene Ether (PPE), modified PPE, polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polysulfone (PSU), modified PSU, polyethersulfone (PES), polyketone (PK), polyetherketone ( PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyarylate (PAR), polyethernitrile (PEN), and the like.

Among these, polycarbonate and/or polyolefin resins are particularly preferred in the present invention. Further, in the present invention, the thermoplastic resin covering the outermost layer (the thermoplastic resin used for the covering layer 12) is the thermoplastic resin 111 impregnated into the reinforcing fiber bundle 112 (the thermoplastic resin used for the reinforcing layer 11). It is preferable that the melting start temperature of the resin 111) or the melting start temperature of the thermoplastic resin covering the outermost layer is 200° C. or less. If the melting start temperature of the thermoplastic resin used for the coating layer 12 is higher than the melting start temperature of the matrix resin, the composite of reinforcing fibers and thermoplastic resin will melt when coating is performed, which will have a negative effect on physical properties. . However, if the thermoplastic resin has a melting start temperature of 200°C or lower, even if it is higher than the melting start temperature of the matrix resin, it can be cooled in a short time, so there is almost no effect on the physical properties, so there is no negative effect. It will not cause any adverse effects.

2. Manufacturing method of fiber-reinforced thermoplastic resin rod-shaped composite 1 FIG. 2 is a diagram schematically showing an outline of the manufacturing method according to the present invention. The manufacturing method according to the present invention is a method for manufacturing the composite body 1 according to the present invention described above, in which at least Step A and Step B are performed. Further, other steps C, D, etc. may be performed as necessary. Each step will be explained in detail below.

(1) Process C
Although this step is not an essential step, it may be performed in the manufacturing method according to the present invention. In step C, the reinforcing fiber bundle F is made available for collection. Specifically, the required number of reinforcing fiber bundles F are pulled out from the creel 10, and if necessary, the reinforcing fiber bundles F are passed through a tension adjusting means into a preheating device whose temperature is not raised (not shown). The reinforcing fiber bundles F group are pulled out and passed through a cooling tank not filled with cooling water (not shown), so that the reinforcing fiber bundles F group can be taken up by the take-up device 20.

(2) Process A
In step A, after the reinforcing fiber bundle F is impregnated with a thermoplastic resin, the reinforcing fiber bundle F impregnated with the thermoplastic resin is twisted. Specifically, the pulling device 20 is driven to take over the group of fiber reinforcing fiber bundles F at a predetermined speed, while applying a predetermined tension to each reinforcing fiber bundle F via the tension adjustment means. The melt extruder 30 is driven while heating the reinforcing fiber bundles F by raising the temperature of the preheating device, supplying the thermoplastic resin to the crosshead die, and forming each reinforcing fiber bundle in the impregnation tank 40. F and a molten thermoplastic resin are brought into contact with each other, each reinforcing fiber bundle F is impregnated with the thermoplastic resin, and while the diameter is adjusted by a diaphragm in the impregnation tank 40, the long fiber reinforcing fibers are formed under atmospheric pressure or below or under pressure. Bundle F is extrusion coated as a wire. Next, twisting is applied to the linear object. In the manufacturing method according to the present invention, the direction of twist may be either unidirectional twist (S twist or Z twist) or SZ twist. Note that the volume content ratio of the reinforcing fibers to the entire reinforcing layer 11 produced in steps A to B can be freely set as appropriate by a person skilled in the art by a conventionally known method, but in the present invention, it is set at 20% or more. It is preferably 80% or less, and more preferably 40% or more and 60% or less.

(3) Process B
In step B, after the step A, the reinforcing fiber bundle F impregnated with the twisted thermoplastic resin is cooled, and the reinforcing layer 11 is produced. Specifically, the twisted linear material is cooled by any one or more methods selected from the group consisting of air cooling, water cooling, or mist spraying, and the twist is formed to form the reinforcing layer 11. Create.

In this process, after step A, the reinforcing fiber bundle F impregnated with the twisted thermoplastic resin is cooled and solidified, so before impregnating the reinforcing fiber bundle F with resin, the reinforcing fiber Twisting can be applied more efficiently than when twisting is applied to the bundle F. When twisting the reinforcing fiber bundle F, the processability is poor as the fibers get tangled. By applying twist after impregnation and solidification, it is possible to prevent the generation of voids and achieve higher density. Note that in step B, twisting may be further applied using a twisting machine.

(4) Process D
In step D, the outermost layer of the produced reinforcing layer 11 is coated with a thermoplastic resin to produce the covering layer 12. Specifically, the melt extruder 30 is driven to supply thermoplastic resin to the crosshead die, and the thermoplastic resin is brought into contact with the outermost layer of the reinforcing layer 11 so that it becomes rod-shaped under pressure. extrusion coating. Next, the fiber-reinforced thermoplastic resin rod-shaped composite 1 is produced by cooling and solidifying by a conventionally known method. The produced composite body 1 according to the present invention may be collected using a collection machine as required, as shown in FIG. In this case, the pulling machine may be equipped with a twisting mechanism, as shown in FIG.

Hereinafter, the present invention will be explained in more detail based on Examples.
It should be noted that the embodiments described below are merely representative embodiments of the present invention, and the scope of the present invention should not be construed narrowly thereby.

<Production of rod-shaped composite made of fiber-reinforced thermoplastic resin>
For Examples 1 to 10 and Comparative Examples 1 and 2, fiber-reinforced thermoplastic resin rod-shaped composites were produced by carrying out the above-mentioned steps C→Step A→Step B→Step D.

FIG. 4 is a diagram schematically showing the outline of the manufacturing method of Comparative Example 3. That is, a fiber-reinforced thermoplastic resin rod-shaped composite was produced by the same manufacturing method as in Examples 1 to 10 and Comparative Examples 1 and 2, except that only the take-up step was performed without performing Step D.

The volume content ratio of the reinforcing fibers (bundles), the twisting direction, the twisting pitch, and the resin species used in the preparation of each Example and each Comparative Example are shown in Table 1 or Table 2 below. In addition, in each Example and each Comparative Example, as mentioned above, glass fiber, which is a preferable fiber as the fiber constituting the reinforcing fiber bundle, is used.

<Evaluation>
A three-point bending test and a heat processability confirmation test were conducted on each of the produced fiber-reinforced thermoplastic resin rod-shaped composites.

[3-point bending test]
For each fiber-reinforced thermoplastic resin rod-shaped composite (N = 5) cut into a length of 100 mm, a universal testing machine was used, and the distance between the fulcrums was the diameter of the fiber-reinforced thermoplastic resin rod-shaped composite × 20 mm, and the speed was A three-point bending test was conducted under the condition of 5.0 mm/min, and the average value of N=5 was taken as the measured value.

As an evaluation method, the obtained measured values were compared with the evaluation below.
300N≦F:〇250N≦F<300N:△
F<250N:×

The inventors of the present application separately conducted a three-point bending test on the fiber-reinforced strand disclosed in JP-A-05-169445 using the method described above, and the result was about 200N.

[Heat workability confirmation test]
Each fiber-reinforced thermoplastic resin rod composite was fixed along the circular metal object (diameter 600 mm) shown in Figure 3, placed in an oven heated to 135°C, heated for 1 hour, and then left at room temperature. After being left for more than 1 hour, each fiber-reinforced thermoplastic resin rod-shaped composite was removed from the circular metal object and evaluated.

As an evaluation method, the condition of each fiber-reinforced thermoplastic resin rod-shaped composite obtained was compared with the following evaluation.
Perfect shaping and no buckling (bentness, whitening, etc.): ◎
No buckling: 〇 Buckling: ×
Note that "the shape is perfect" here means that the shape of the fiber-reinforced thermoplastic resin rod-shaped composite changes when it is removed from the fixing jig (= the circular metal object shown in Figure 3). It means not to do something.

<Evaluation>
The results of each evaluation are shown in Tables 1 and 2 below.

<Consideration>
The fiber-reinforced thermoplastic resin rod-shaped composites of Examples 1 to 10 were superior in bending strength compared to the fiber-reinforced thermoplastic resin rod-shaped composites of Comparative Examples 1 to 3. Furthermore, the fiber-reinforced thermoplastic resin rod-shaped composites of Examples 1 to 10 were also superior in thermal processability compared to the fiber-reinforced thermoplastic resin rod-shaped composites of Comparative Examples 1 and 2. Therefore, the reinforcing layer includes at least a reinforcing layer formed of a reinforcing fiber bundle impregnated with a thermoplastic resin, and one or more coating layers that cover the outermost side of the reinforcing layer with a thermoplastic resin. is in a twisted state, and the volume content ratio of the reinforcing fibers is 20% or more and 80% or less with respect to the entire reinforcing layer, thereby providing a fiber-reinforced thermoplastic resin rod with excellent bending strength. It has been found that it is possible to provide a complex with a similar shape.

According to the present invention, the main object is to provide a fiber-reinforced thermoplastic resin rod-shaped composite having excellent bending strength and a method for manufacturing the same. Therefore, by taking advantage of its excellent bending strength, it is expected that it will be used more than ever before in a wide range of fields such as automobile parts, electronic parts, agricultural and forestry materials, construction materials, furniture, etc. as a material that replaces metal products. can.

1: Fiber-reinforced thermoplastic resin rod-shaped composite 11: Reinforced layer 111: Thermoplastic resin (matrix resin) used for the reinforced layer 11
112, F: Reinforcing fiber bundle 12: Covering layer

Claims (3)

a reinforcing layer formed by reinforcing fiber bundles impregnated with thermoplastic resin;
one or more coating layers that cover the outermost side of the reinforcing layer with a thermoplastic resin;
comprising at least
The reinforcing layer is in a twisted state,
A rod-shaped composite made of fiber-reinforced thermoplastic resin, wherein the volume content ratio of the reinforcing fibers is 20% or more and 80% or less with respect to the entire reinforcing layer. The thermoplastic resin covering the outermost side is below the melting start temperature of the thermoplastic resin impregnated into the reinforcing fiber bundle, or the melting start temperature of the thermoplastic resin covering the outermost side is 200°C or below. The fiber-reinforced thermoplastic resin rod-shaped composite according to claim 1. At least a reinforcing layer formed of a reinforcing fiber bundle impregnated with a thermoplastic resin, and one or more coating layers covering the outermost side of the reinforcing layer with a thermoplastic resin, the reinforcing layer comprising: A method for producing a fiber-reinforced thermoplastic resin rod-shaped composite, wherein the reinforcing fiber is in a twisted state and the volume content ratio of the reinforcing fiber is 20% or more and 80% or less with respect to the entire reinforcing layer, ,
After impregnating the reinforcing fiber bundle with a thermoplastic resin, a step A of imparting twist to the reinforcing fiber bundle impregnated with the thermoplastic resin;
After the step A, a step B of cooling the reinforcing fiber bundle impregnated with a twisted thermoplastic resin to produce a reinforcing layer;
A method for producing a rod-shaped composite made of fiber-reinforced thermoplastic resin, the method comprising: