Impregnation tank for producing fiber-reinforced resin composites

Abstract

To provide an impregnation tank for producing a fiber-reinforced resin composite, which can produce a fiber-reinforced resin composite in which thermal degradation is suppressed.SOLUTION: The present invention relates to an impregnation tank for producing fiber-reinforced resin composites which has a bottom surface substantially parallel to the ground for impregnating a continuously traveling reinforcing fiber bundle with a thermoplastic resin, wherein the impregnation tank comprises: an impregnation section for impregnating molten thermoplastic resin while opening the reinforcement fiber bundle; a forming section located downstream of the impregnation section in the MD direction of the impregnation tank for forming the molten thermoplastic resin into a desired shape while squeezing it during impregnation; and a supply port for introducing molten thermoplastic resin only into the forming section.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an impregnation tank for producing a fiber-reinforced resin composite. More specifically, the present invention relates to an impregnation tank for producing a fiber-reinforced resin composite and a method for producing a fiber-reinforced resin composite, which can produce a fiber-reinforced resin composite with reduced thermal degradation. [Background technology]

[0002] Fiber-reinforced plastic (FRP) articles, in which reinforcing fibers are bound with synthetic resin, are strong and lightweight and are used as alternatives to metal articles in a wide range of fields, including automotive parts, electronic components, agricultural and forestry materials, building materials, furniture, etc. One product that uses this FRP technology is pipes, rods, linear objects, etc., which use long fiber bundles such as glass roving as reinforcing fibers and a thermosetting resin matrix, and have long been used in various industrial fields.

[0003] In recent years, various needs have arisen, one of which is a demand for fiber-reinforced resin composites in which thermal degradation of the resin is suppressed. Suppressing thermal degradation of the resin makes discoloration less likely. In response to this demand, for example, Patent Document 1 discloses a method for suppressing thermal degradation of the thermoplastic resin in an impregnation tank by passing the reinforcing fiber bundle through a chamber into which an inert gas is introduced and then drawing it into the impregnation tank. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-1961 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even when the above-mentioned Patent Document 1 or the like is used, it is not possible to completely eliminate oxygen from flowing into the impregnation tank, and therefore there is a problem that it is difficult to completely suppress oxidation of the thermoplastic resin, particularly in the case of long-term production.

[0006] In view of the above circumstances, the present invention has as its main object to provide an impregnation tank for producing fiber-reinforced resin composites, which can produce fiber-reinforced resin composites that are inhibited from thermal degradation. [Means for solving the problem]

[0007] As a result of intensive experimental investigations, the present inventors have discovered an impregnation tank for producing fiber-reinforced resin composites, which, by focusing particularly on the structure of the impregnation tank, can produce fiber-reinforced resin composites in which thermal degradation of the thermoplastic resin is suppressed, and have completed the present invention.

[0008] The present invention first provides an impregnation tank for producing fiber-reinforced resin composites, the impregnation tank having a bottom surface substantially parallel to the ground and used to impregnate a continuously running reinforcing fiber bundle with a thermoplastic resin, the impregnation tank having an impregnation section that impregnates the reinforcing fiber bundle with molten thermoplastic resin while spreading the fiber bundle, and a shaping section that is located after the impregnation section in the MD direction of the impregnation tank and squeezes the molten thermoplastic resin while impregnating the fiber bundle to form it into a desired shape, and a supply port for introducing the molten thermoplastic resin is provided only in the shaping section. In the present invention, the ratio of the impregnation section to the molding section may be in the range of 3:7 to 7:3 over the entire length of the impregnation tank in the MD direction. The present invention also provides a method for producing a fiber-reinforced resin composite, which includes at least a take-up step of continuously running a reinforcing fiber bundle through a molten thermoplastic resin and taking up the resin-impregnated reinforcing fiber bundle through the above-mentioned impregnation tank for producing the fiber-reinforced resin composite. [Effects of the Invention]

[0009] According to the present invention, a fiber-reinforced resin composite in which thermal degradation is suppressed can be obtained. The effects described here are not necessarily limited to those described herein, and may be any of the effects described in this specification. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing a schematic structure of a fiber-reinforced resin composite 1. FIG. [Figure 2] 1 is a diagram schematically illustrating an outline of a method for producing a fiber-reinforced resin composite 1. FIG. [Figure 3] FIG. 1 is a diagram schematically illustrating an impregnation tank 40 for producing a fiber-reinforced resin composite 1. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiment described below is merely an example of a typical embodiment of the present invention, and the scope of the present invention should not be construed as being narrow.

[0012] 1. Fiber-reinforced resin composite 1 1A and 1B are diagrams schematically illustrating the structure of a fiber-reinforced resin composite 1. The fiber-reinforced resin composite 1 (hereinafter also simply referred to as "composite 1") includes at least a reinforcing layer 11 (see FIG. 1A) and, as necessary, one or more coating layers 12 (see FIG. 1B).

[0013] The composite 1 can be molded into a desired shape, and examples of such shapes include a rod shape as shown in Fig. 1, a rectangular prism shape such as a substantially triangular prism or a substantially square prism, etc. The term "rod shape" as used herein specifically refers to a shape whose cross section is a flat shape such as a circle or an oval.

[0014] Since composite 1 inhibits oxidation of the thermoplastic resin and prevents discoloration, it is expected to be used more widely than ever before as an alternative to metal products in a wide range of fields, such as automotive parts, electronic parts, agricultural and forestry materials, building materials, and furniture. Each layer will be described in detail below.

[0015] (1) Reinforcement layer 11 1, the reinforcing layer 11 is a layer formed of reinforcing fiber bundles 112 impregnated with a thermoplastic resin 111. Reinforcing fibers impregnated with a thermoplastic resin are generally called fiber reinforced thermoplastic resin (FRTP).

[0016] <Reinforcing fiber bundle 112> The reinforcing fiber bundles 112 used in the present invention are preferably substrates in the form of continuous long fiber bundles or fiber braids (for example, woven fabrics, knitted fabrics, braided fabrics, etc.). By using these, continuous impregnation and continuous formation of the coating layer 12 can be ensured, and the fiber-reinforced resin composite 1 can be produced with excellent productivity.

[0017] Examples of fibers that can be used to form the reinforcing fiber bundles 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; metal fibers such as boron fibers, copper fibers, and stainless steel fibers; amorphous fibers; natural fibers such as kenaf fibers; and polyamide fibers such as nylon 6 and nylon 66. Also, in the present invention, blends of these fibers can also be used. Furthermore, in the present invention, these fibers may be used alone or in combination of two or more.

[0018] In the present invention, it is particularly preferable to use glass fibers and / or carbon fibers among these.

[0019] Furthermore, in the present invention, it is preferable to use biodegradable fibers. This can contribute to the achievement of the SDGs. Examples of biodegradable fibers include the above-mentioned natural fibers; biodegradable polyester fibers such as polycaprolactone, polyethylene succinate, polybutylene succinate, polyethylene adipate, polybutylene adipate, polyethylene succinate-adipate copolymer, polylactic acid, and polyester fibers in which these are used as the main component and other dicarboxylic acids and / or glycols are copolymerized. Furthermore, in the present invention, these fibers may be used alone or in combination.

[0020] Examples of glass fibers that can be used include long fibers such as glass fiber monofilaments, glass fiber strands, glass fiber rovings, and glass fiber yarns. In the present invention, it is particularly preferable to use glass fiber rovings and / or glass fiber yarns. Also, glass fiber braids such as glass fiber woven fabrics, glass fiber braids, and glass fiber knitted fabrics may be used.

[0021] 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. Examples of the glass composition of the glass fiber include E-glass, S-glass, and C-glass. Degradable or biosoluble glass fibers may also be used. Among these, E-glass is particularly preferred in the present invention. The cross section of the glass fiber monofilament may be substantially circular or may be a flat shape such as a substantially oval.

[0022] The reinforcing fiber bundle 112 can be prepared in advance as needed by a conventionally known method such as weaving, braiding, or knitting to a desired length, or a long one can be wound up on a roll and used. The reinforcing fiber bundle 112 can also be heated to improve the impregnation of the resin into the reinforcing fibers or to remove moisture from the reinforcing fibers.

[0023] The volume content of the reinforcing fibers (bundles) 112 is preferably 20% to 80% of the entire reinforcing layer 11, and more preferably 40% to 60%. If the volume content is lower than 20%, the reinforcing effect of the reinforcing fibers is reduced. Conversely, if the volume content is higher than 80%, the amount of resin is too small, which adversely affects bending strength.

[0024] <Thermoplastic resin 111 used in the reinforcing layer 11> Examples of the thermoplastic resin 111 used as the matrix resin in the present invention include polyolefin resins such as polypropylene (PP), polyethylene (PE), and polyisobutylene (PB); polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PENp), and liquid crystal polyester (LCP); styrene resins such as polystyrene (PS), acrylonitrile-styrene resin (AS), acrylonitrile-butadiene-styrene resin (ABS), acrylonitrile-acrylic-styrene resin (AAS), and acrylonitrile-ethylene propylene rubber-styrene (AES); urethane resin, nylon 6, and the like. Other examples include 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), etc. In the present invention, these may be used alone or in combination of two or more.

[0025] Furthermore, in the present invention, it is preferable to use a biodegradable thermoplastic resin. This can contribute to the achievement of the SDGs. Examples of biodegradable thermoplastic resins include polylactic acid (PLA), polyglycolic acid (PGA), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), polybutylene adipate / terephthalate (PBAT), polyethylene terephthalate succinate (PETS), polybutylene succinate adipate (PBSA), polybutylene succinate (PBS), poly(ε-caprolactone) (PCL), polyamide 4 (PA4), and poly(3-hydroxybutanoic acid) (P(3HB)). Furthermore, in the present invention, these may be used alone or in combination of two or more.

[0026] In addition, to the above-mentioned thermoplastic resin, one or more of various additives may be added as needed to obtain desired physical properties. Specific examples of additives that can be added include ultraviolet absorbers, antioxidants, stabilizers such as heat stabilizers, pigments, dyes, lubricants, flame retardants, mold release agents, and sliding improvers. Furthermore, to further enhance biodegradability, biodegradable modifiers and the like may be added.

[0027] <Twist in reinforcement layer 11> In the present invention, the reinforcing layer 11 may be twisted or untwisted. If twisted, it may be unidirectional (S twist or Z twist) or SZ twist.

[0028] Regarding the position where twisting is performed, if there is no coating layer 12, it may be performed at any position between the water-cooling bath 50 and the take-up device 60, which will be described later. Note that twisting and take-up may be performed simultaneously, as in a rotary take-up device, but twisting cannot be performed after the take-up device 60. If there is a coating layer 12, it may be performed at any position between the water-cooling bath 50 and the take-up device 60, which will be described later (or take-up and twisting are performed at the same position), but in this case, the coating step of forming the coating layer 12 will be performed after the take-up device 60. Note that if twisting is not performed, the coating step may be performed anywhere after the exit of the impregnation bath 40. Furthermore, the method of twisting may be performed by a conventionally known method, and is not particularly limited.

[0029] (2) Covering layer 12 The coating layer 12 is not an essential component, but is one or more layers that coat the outermost surface of the reinforcing layer 11 with a thermoplastic resin. Although Fig. 1B depicts a case where there is one coating layer 12, in the present invention, there may be two or more coating layers 12. Examples of a structure where there are two or more coating layers 12 include a structure in which part or all of a first coating layer 12 that covers the reinforcing layer 11 is covered in turn with second or more coating layers 12.

[0030] <Thermoplastic Resin Used in Coating Layer 12> The thermoplastic resin used for the coating layer 12 may be, for example, the thermoplastic resin 111 as the matrix resin described above.

[0031] In the present invention, it is particularly preferable to use polycarbonate and / or polyolefin resins among these. Furthermore, biodegradable thermoplastic resins may also be used.

[0032] Furthermore, in the present invention, it is preferable that the thermoplastic resin coating the outermost layer (the thermoplastic resin used for the coating layer 12) has a melting start temperature equal to or lower than the melting start temperature of the thermoplastic resin 111 (the thermoplastic resin 111 used for the reinforcing layer 11) impregnated into the reinforcing fiber bundles 112, or that the melting start temperature of the thermoplastic resin coating the outermost layer is 200°C or lower. 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 the reinforcing fibers and the thermoplastic resin will melt during coating, adversely affecting the 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, cooling can be performed in a short time, so there is almost no adverse effect on the physical properties, and therefore no adverse effects will occur.

[0033] 2. Manufacturing method of fiber reinforced resin composite 1 FIG. 2 is a diagram schematically illustrating an outline of a method for producing a fiber-reinforced resin composite 1, and FIG. 3 is a diagram schematically illustrating an outline of an impregnation tank 40 (hereinafter also simply referred to as "impregnation tank 40") for producing a fiber-reinforced resin composite 1 according to the present invention.

[0034] The method for producing the composite 1 according to the present invention includes at least step B. If necessary, other steps may be performed. The composite 1 produced below is a production method for a case where the composite 1 does not have a coating layer 12 (see A in FIG. 1).

[0035] The composite 1 having the coating layer 12 can be produced by a conventionally known method. The coating step of forming the coating layer 12 may be performed between the impregnation tank 40 and the water-cooling tank 50, or may be performed after the outer diameter is determined by the water-cooling tank 50. When the coating layer 12 is formed from the outlet of the impregnation tank 40, the step may be any step between the outlet of the impregnation tank 40 and the take-up device 60. Each step will be described in detail below. The impregnation tank 40 itself will be described separately below.

[0036] (1) Process A This step is not essential, but may be carried out in the method for producing the composite 1 according to the present invention. Step A is a step of making the reinforcing fiber bundles 112 ready to be taken up. More specifically, a required number of reinforcing fiber bundles 112 (see also "10" in FIG. 2) are pulled out from the creel 20, and if necessary, the reinforcing fiber bundles 112 are passed through a preheating device (not shown) that has not yet been heated via a tension adjusting means, and the group of reinforcing fiber bundles 112 is pulled out from the impregnation tank 40 and passes through a cooling tank (not shown) that is not filled with cooling water, so that the group of reinforcing fiber bundles 112 can be taken up by the take-up device 60.

[0037] (2) Process B This step is an essential step. In step B, the reinforcing fiber bundle 112 is continuously run through a molten thermoplastic resin, and the resin-impregnated reinforcing fiber bundle is passed through an impregnation tank 40 and taken up.

[0038] More specifically, while the group of reinforcing fiber bundles 112 is taken up at a predetermined speed via the creel 20, a predetermined tension is applied to each reinforcing fiber bundle 112 via a tension adjusting means, the preheating device is heated to heat the reinforcing fiber bundles 112, the melt extruder 30 is driven, a thermoplastic resin is supplied to the crosshead die, each reinforcing fiber bundle 112 is brought into contact with the molten thermoplastic resin in the impregnation tank 40, each reinforcing fiber bundle 112 is impregnated with the thermoplastic resin, and the reinforcing fiber bundles 112 (also referred to as "long fiber reinforcing fiber bundles 112") are extrusion coated as a linear object at subatmospheric pressure or under pressure while adjusting the diameter with a draw in the impregnation tank 40. The linear object is then cooled in a water-cooled tank 50 and taken up by a take-up device 60.

[0039] The volume content ratio of the reinforcing fibers (bundles) to the entire reinforcing layer 11 produced in steps A and B can be freely set by a person skilled in the art using conventionally known methods, but in the present invention, it is preferably 20% or more and 80% or less, and more preferably 40% or more and 60% or less.

[0040] Although not shown, the reinforcing fiber bundles 112 may be twisted after being extrusion coated as linear objects. The reinforcing fiber bundles 112 impregnated with twisted thermoplastic resin are cooled to produce the reinforcing layer 11. If no twist is imparted, the reinforcing fiber bundles 112 impregnated with untwisted thermoplastic resin are cooled to produce the reinforcing layer 11. Specifically, the linear objects are cooled by water cooling and shaped to produce the reinforcing layer 11.

[0041] Air cooling, mist spraying, etc. may also be used in combination with water cooling. Air cooling may be performed at multiple locations rather than just one, and a flow rate of 50 L / min or more is preferred. The air slit used for air cooling comes in a variety of shapes, including ring and flat, but a ring shape is preferred as it allows for more uniform air application.

[0042] A dedicated part (nozzle) for forming into a desired shape may be attached to the outlet of the impregnation tank. The nozzle diameter, size, length, and nozzle temperature control method are not particularly limited. The nozzle temperature may be controlled in multiple stages. The nozzle length may be, for example, 10 mm to 300 mm.

[0043] 3. Impregnation tank 40 for manufacturing fiber-reinforced resin composite 1 In the past, thermal degradation of the reinforcing fiber bundles 112 in the impregnation tank 40 has been a problem. To improve the impregnation of the reinforcing fiber bundles 112 with a thermoplastic resin, it is necessary to sufficiently reduce the viscosity by heat, but if the reinforcing fiber bundles 112 are left in such conditions for a long period of time, the effects of thermal degradation occur. Specifically, thermal degradation refers to oxidation, hydrolysis, crosslinking, depolymerization, etc., which cause a deterioration in the physical properties of the thermoplastic resin and a change in its appearance. Furthermore, impregnation of the reinforcing fiber bundles 112 with thermally degraded resin has been problematic, as it can cause discoloration and a deterioration in the physical properties of the fiber-reinforced resin composite 1.

[0044] In the present invention, the impregnation tank 40 is used for producing the fiber-reinforced resin composite 1, and has a bottom surface approximately parallel to the ground for impregnating the continuously running reinforcing fiber bundles 112 with a thermoplastic resin. The impregnation tank 40 also has an impregnation section 401 that impregnates the reinforcing fiber bundles 112 with molten thermoplastic resin while spreading them, and a shaping section 402 that is located after the impregnation section 401 in the MD direction (i.e., the fiber flow direction) of the impregnation tank 40 and impregnates the reinforcing fiber bundles 112 with the molten thermoplastic resin while squeezing it to form a desired shape, and a supply port for introducing the molten thermoplastic resin is provided only in the shaping section 402, not in the impregnation section 401.

[0045] In a situation where the reinforcing fiber bundle 112 passing through the impregnation tank 40 is continuously taken up by the take-up device 60, the thermoplastic resin in the impregnation tank 40 flows from the impregnation section 401 of the impregnation tank 40 toward the molding section 402 due to the accompanying flow. Therefore, as time passes since the thermoplastic resin was supplied to the impregnation tank 40, the thermoplastic resin that has thermally deteriorated tends to remain mainly in the molding section 402 of the impregnation tank 40. Furthermore, the portion in the impregnation tank 40 where the fibers are impregnated with the resin is mainly the impregnation section 401 provided in the first half of the impregnation tank 40, and the thermoplastic resin that remains in the second half often remains without being discharged. However, this state of retention is undesirable because some of the thermoplastic resin that remains in the second half may also be mixed into the product.

[0046] In the above situation, if the resin supply port, which is the focus of the present invention, is provided in the molding section 402 of the impregnation tank 40, new thermoplastic resin that has not been thermally degraded and old thermoplastic resin that has been thermally degraded will mix, diluting the degree of resin degradation. On the other hand, if the resin supply port is provided in the impregnation section 401 in the first half of the impregnation tank 40, the thermally degraded thermoplastic resin will continue to remain in the molding section 402 in the second half, causing adverse effects such as discoloration of the product and deterioration of its physical properties. Note that the term "old thermoplastic resin" here refers to thermoplastic resin that has been introduced through the resin supply port for a certain period of time and has discolored due to thermal degradation. On the other hand, the term "new thermoplastic resin" refers to thermoplastic resin that has been introduced through the resin supply port immediately after introduction.

[0047] Due to the above-mentioned dilution of the degree of resin degradation, the composite 1 produced using the impregnation tank 40 is prevented from thermally deteriorating the thermoplastic resin, and discoloration is suppressed.

[0048] The impregnation tank 40 may also be a sealed type. In this specification, the term "sealed type" refers to an impregnation tank 40 having a structure that basically has no open parts communicating with the outside air, except for a hole for introducing the reinforcing fiber bundle 112 into the impregnation section 401 and a hole for discharging the resin-impregnated fiber bundle into the molding section 402. However, an openable hole may be provided to allow the interior of the impregnation tank 40 to be checked. Furthermore, when an inert gas is introduced into the impregnation tank 40, an outlet may be provided to discharge excess thermoplastic resin supplied to the impregnation tank 40.

[0049] Here, the impregnation section 401 is characterized by being equipped with supports such as round rods and lattice-like guides, through which the reinforcing fiber bundles 112 are passed to open the fibers and impregnate them with the thermoplastic resin. The shaping section 402 is characterized by passing the reinforcing fiber bundles 112 after passing through the impregnation section 401 through holes (hereinafter simply referred to as "apertures") of the target shape that matches the cross-sectional shape when the reinforcing fiber bundles 112 are finally drawn into various shapes, such as the above-mentioned rod shape, approximately triangular prism, approximately square prism, etc. Two or more apertures are preferably provided, and in this case, the aperture holes are preferably arranged so that their sizes gradually decrease toward the outlet side.

[0050] Furthermore, in order to improve impregnation, a round opening bar may be introduced into the impregnation tank 40 to squeeze and pull out the fibers. Furthermore, the impregnation tank 40 may be provided with a discharge port for discharging the resin composition that has accumulated and deteriorated, air bubbles, fluff, foreign matter, etc., and it is preferable that a resin discharge port is formed independently. The discharge port is preferably located downstream of the impregnation tank 40, and its shape is not particularly limited, and may be slit-shaped, circular, or the like. It is also preferable that the opening of the discharge port is adjustable.

[0051] The location of the resin supply port is not particularly limited as long as it is installed in the molding section 402, but it is preferable to install it on the outlet side of the resin-impregnated fiber bundle because this can reduce the amount of resin that remains. Furthermore, the size and shape of the supply port are not particularly limited.

[0052] Specifically, the ratio of the impregnation section 401 to the molding section 402 is preferably in the range of 3:7 to 7:3, and more preferably 7:3 to 5:5, over the entire length in the MD of the impregnation tank 40. If the impregnation section 401 is less than 30% of the entire length, impregnation may be insufficient, and if the molding section 402 is less than 30% of the entire length, the dimensional stability of the cross-sectional shape of the obtained fiber-reinforced resin composite 1 may be insufficient.

[0053] In the present invention, the impregnation tank 40 and the reinforcing fiber bundles 112 before entering the impregnation tank 40 may be purged with an inert gas such as nitrogen or argon. Purging with an inert gas can suppress oxidation, hydrolysis, and the like of the thermoplastic resin. There are no particular restrictions on the temperature of the inert gas, but it is preferable that the inert gas be heated to a temperature equivalent to that of the thermoplastic resin in order to prevent fluctuations in the resin temperature.

[0054] The reinforcing fiber bundles may be heated with an infrared heater, hot air, or the like before entering the impregnation tank 40. Preheating the reinforcing fiber bundles 112 can suppress a decrease in the temperature of the molten resin in the impregnation tank 40, thereby improving the impregnation properties. [Example]

[0055] The present invention will be described in more detail below based on examples. The embodiment described below is merely a representative example of the present invention, and the scope of the present invention should not be construed as being narrow.

[0056] <Production of fiber-reinforced resin composites> [Example 1] Five pieces of 2200 tex glass fiber roving (Nitto Boseki, RS220RL-510AH) and one piece of 1150 tex glass fiber roving (Nitto Boseki, RS110QL-533AH) were placed on a stand, and the fibers were passed through an impregnation tank with a 3:7 ratio of impregnation section to molding section, where the molding section was equipped with a thermoplastic resin supply port. The fibers exiting the impregnation tank were then passed through a water-cooled tank and a take-up device. The water-cooled tank was then filled with water, and the impregnation tank was filled with polycarbonate resin (Mitsubishi Engineering Plastics, HL-8002). The fibers were then drawn out by the take-up device at a speed of 1.5 m / min, yielding a fiber-reinforced resin composite with an outer diameter of 3.5 mm and a roughly circular cross section.

[0057] A 3m sample was taken from the fiber-reinforced resin composite obtained by the above method 3 hours after the thermoplastic resin was fed into the impregnation tank. The appearance of the sample was then visually inspected, and any black-brown discoloration with a maximum diameter of 0.5mm or more was considered to be oxides, which were counted and evaluated to determine the number per meter. The moldability and impregnation properties were also evaluated.

[0058] [Example 2] A fiber-reinforced resin composite was obtained in the same manner as in Example 1, except that the ratio of the impregnated portion to the molded portion was set to 6:4. Evaluations were also carried out in the same manner as in Example 1.

[0059] [Example 3] A fiber-reinforced resin composite was obtained in the same manner as in Example 1, except that the ratio of the impregnated portion to the molded portion was set to 7:3.

[0060] [Example 4] A fiber-reinforced resin composite was obtained in the same manner as in Example 1, except that the ratio of the impregnated portion to the molded portion was set to 2:8.

[0061] [Example 5] A fiber-reinforced resin composite was obtained in the same manner as in Example 1, except that the ratio of the impregnated portion to the molded portion was set to 8:2.

[0062] [Comparative Example 1] Five pieces of 2200 tex glass fiber roving (Nitto Boseki, RS220RL-510AH) and one piece of 1150 tex glass fiber roving (Nitto Boseki, RS110QL-533AH) were placed on a stand, and these fibers were passed through an impregnation tank with an impregnation section to molding section ratio of 3:7 and a thermoplastic resin supply port in the impregnation section. Otherwise, a fiber-reinforced resin composite was obtained in the same manner as in Example 1. Evaluations were also performed using the same methods as in Example 1.

[0063] [Example 6] Five pieces of 2200 tex glass fiber roving (Nitto Boseki, RS220RL-510AH) and one piece of 1150 tex glass fiber roving (Nitto Boseki, RS110QL-533AH) were placed on a stand. Next, the fibers were passed through a 2 L inert gas purge box equipped with an oxygen concentration meter, and nitrogen gas was introduced into the box until the oxygen concentration inside the box reached 2%. The fibers were then passed through an impregnation tank with a 3:7 ratio of impregnation section to molding section, which had a thermoplastic resin supply port in the molding section. The fibers exited the impregnation tank and were then passed through a water-cooled tank and a take-up device. The water-cooled tank was filled with water, and the impregnation tank was filled with polycarbonate resin (Mitsubishi Engineering Plastics, HL-8002). The fibers were then drawn out at a speed of 1.5 m / min using the take-up device to obtain a fiber-reinforced resin composite with an outer diameter of 3.5 mm and a roughly circular cross section. In addition, evaluation was carried out in the same manner as in Example 1.

[0064] [Example 7] A fiber-reinforced resin composite was obtained in the same manner as in Example 6, except that the ratio of the impregnated portion to the molded portion was set to 6:4. Evaluations were also carried out in the same manner as in Example 6.

[0065] [Example 8] A fiber-reinforced resin composite was obtained in the same manner as in Example 6, except that the ratio of the impregnated portion to the molded portion was set to 7:3.

[0066] [Example 9] A fiber-reinforced resin composite was obtained in the same manner as in Example 6, except that the ratio of the impregnated portion to the molded portion was set to 2:8. Evaluations were also carried out in the same manner as in Example 6.

[0067] [Example 10] A fiber-reinforced resin composite was obtained in the same manner as in Example 6, except that the ratio of the impregnated portion to the molded portion was set to 8:2. Evaluations were also carried out in the same manner as in Example 6.

[0068] Comparative Example 2 Five pieces of 2200 tex glass fiber roving (Nitto Boseki, RS220RL-510AH) and one piece of 1150 tex glass fiber roving (Nitto Boseki, RS110QL-533AH) were placed on a stand. Next, the fibers were passed through a 2-L inert gas purging box equipped with an oxygen concentration meter, and nitrogen gas was introduced to adjust the oxygen concentration inside the box to 2%. The fibers were then passed through an impregnation tank with a 3:7 ratio of impregnation zone to molding zone and a thermoplastic resin supply port in the impregnation zone. Otherwise, a fiber-reinforced resin composite was obtained in the same manner as in Example 6. Evaluations were also performed using the same methods as in Example 6.

[0069] <Evaluation method> The moldability and impregnation properties of each of the composites produced were evaluated by the following methods. [Moldability] Orifices with the same shape but with cross-sectional areas 1.1 times and 1.2 times larger than the smallest orifice hole installed in the molding section were prepared, and if the composite produced could pass through an orifice 1.1 times larger, it was evaluated as ◎, and if the composite produced could pass through an orifice 1.2 times larger, it was evaluated as ○. [Impregnability] Using the cross-sectional area of ​​the smallest aperture hole installed in the molding section as the standard, the ideal unit weight was calculated when the fibers and resin used were filled without any gaps in that cross-sectional area.Then, if the unit weight of the composite actually obtained was 0.9 times or more of the ideal unit weight, it was evaluated as ◎, and if it was 0.8 times or more, it was evaluated as ◯.

[0070] <Evaluation results> The evaluation results are shown in Tables 1 and 2 below.

[0071] [Table 1]

[0072] [Table 2]

[0073] <Consideration> It was found that the composites of Examples 1 to 5 had fewer discolored points and less thermal degradation than Comparative Example 1. It was also found that the composites of Examples 6 to 10, which were purged, had fewer discolored points and less thermal degradation than Comparative Example 2.

[0074] Therefore, it was found that a fiber-reinforced resin composite with reduced thermal degradation can be obtained by manufacturing using an impregnation tank for manufacturing fiber-reinforced resin composites, which has a bottom surface approximately parallel to the ground for impregnating a continuously running reinforcing fiber bundle with a thermoplastic resin, the impregnation tank having an impregnation section that impregnates the molten thermoplastic resin while spreading the reinforcing fiber bundle, and a molding section that impregnates the molten thermoplastic resin while squeezing it in the molten thermoplastic resin and molds it into a desired shape after the impregnation section in the MD direction of the impregnation tank, and which has a supply port for introducing the molten thermoplastic resin only into the molding section. [Industrial Applicability]

[0075] According to the present invention, a fiber-reinforced resin composite can be obtained that is inhibited from thermal degradation and discoloration. Therefore, by taking advantage of the characteristics of inhibited thermal degradation and discoloration, it is expected that the fiber-reinforced resin composite will be used more widely than ever as a material to replace metal articles in a wide range of fields, such as automotive parts, electronic parts, agricultural and forestry materials, building materials, and furniture. [Explanation of symbols]

[0076] 1: Fiber-reinforced composite 11: Reinforcement layer 111: Thermoplastic resin (matrix resin) used in the reinforcing layer 11 112,10: Reinforcing fiber bundle 12: Covering layer 20: Creel 30: Melt extruder 40: Impregnation tank 401: Impregnation part 402: Molding section 50: Cooling tank 60: Take-off device

Claims

1. An impregnation tank having a bottom surface approximately parallel to the ground for impregnating a continuously running reinforcing fiber bundle with a thermoplastic resin, The impregnation tank has an impregnation section that impregnates the reinforcing fiber bundles with molten thermoplastic resin while spreading the fiber bundles, and a shaping section that is located after the impregnation section in the MD direction of the impregnation tank and that impregnates the reinforcing fiber bundles with the molten thermoplastic resin while squeezing the fiber bundles, thereby shaping the fiber bundles into a desired shape, An impregnation tank for producing a fiber-reinforced resin composite, wherein a supply port for introducing molten thermoplastic resin is provided only in the molding section.

2. Over the entire length of the impregnation tank in the MD direction, 2. The impregnation tank for producing fiber-reinforced resin composites according to claim 1, wherein the ratio of the impregnation section to the molding section is in the range of 3:7 to 7:

3.

3. 2. A method for producing a fiber-reinforced resin composite, comprising at least a take-up step of continuously running a reinforcing fiber bundle through a molten thermoplastic resin and passing the resin-impregnated reinforcing fiber bundle through the impregnation tank for producing the fiber-reinforced resin composite according to claim 1.

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