Composite molded articles and methods for manufacturing the same, nonwoven fabrics for composite molded articles, and fibers for composite molded article matrices.

Abstract

To provide a composite molding which is more excellent in mechanical physical properties.SOLUTION: A composite molding contains a reinforcement fiber, and two or more kinds of thermoplastic resins as a matrix, wherein the matrix contains a crystalline thermoplastic resin and an amorphous thermoplastic resin, the crystalline thermoplastic resin has a Vicat softening temperature measured according to JIS K 7206 B50 of 60°C or higher and 260°C or lower, the amorphous thermoplastic resin has a Vicat softening temperature measured according to JIS K 7206 B50 of 60°C or higher and 300°C or lower, and the matrix includes three or more sections, and is formed by melting a composite fiber where each of the sections is exposed to the fiber surface and / or the one section occupies at least 60% of the outer periphery of a cross section of the fiber.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to a composite molded article containing two or more thermoplastic resins as a matrix, a method for producing the same, a nonwoven fabric for a composite molded article containing composite fibers made of two or more thermoplastic resins as matrix-forming fibers, and fibers for a composite molded article matrix. [Background technology]

[0002] Fiber-reinforced plastics (FRP, hereinafter also simply referred to as "composite molded products") are materials that improve strength by incorporating fibers into the matrix resin (also called the base resin). Their excellent lightweight, high strength, and corrosion resistance make them suitable for use in various fields. Glass fibers, carbon fibers, and aramid fibers are used as reinforcing fibers in composite molded products, while thermosetting resins are widely used as the matrix resin. However, thermosetting resins have drawbacks, such as relatively long molding times and poor recyclability. Therefore, thermoplastic resins tend to be used as the matrix resin, especially when recyclability is a consideration.

[0003] When using thermoplastic resin as a matrix resin, a method has been proposed to obtain a composite molded article by mixing reinforcing fibers with synthetic fibers made of the resin to be the matrix resin to produce a nonwoven fabric or web, and then melting and solidifying the synthetic fibers (Patent Documents 1 to 9). Furthermore, it has been exemplified or described that the synthetic fibers may be core-sheath type composite fibers or side-by-side type composite fibers made of a high-melting-point polymer component and a low-melting-point polymer component (Patent Documents 1, 3 to 5, 7), and that the matrix resin may be a combination of resins of the same group (Patent Documents 2, 3, 4, 5 to 6). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2011-190549 [Patent Document 2] Patent No. 3792960 [Patent Document 3] Japanese Patent Publication No. 2013-204187 [Patent Document 4] Japanese Patent Publication No. 2018-130939 [Patent Document 5] Patent No. 6555777 [Patent Document 6] Patent No. 5855869 [Patent Document 7] Japanese Utility Model Publication No. 3-120592 [Patent Document 8] Japanese Patent Publication No. 2007-46197 [Patent Document 9] Patent No. 6550644 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] This disclosure aims to provide a composite molded article with superior mechanical properties, and a nonwoven fabric for composite molded articles that enables the manufacture of such composite molded articles. Furthermore, this disclosure aims to provide a fiber for a composite molded article matrix that is suitable for providing a composite molded article with superior mechanical properties. [Means for solving the problem]

[0006] This disclosure relates to a composite molded article comprising reinforcing fibers and two or more thermoplastic resins as a matrix, The matrix comprises a crystalline thermoplastic resin and an amorphous thermoplastic resin. The crystalline thermoplastic resin has a Vicat softening temperature of 60°C to 260°C, as measured according to the JIS K 7206 B50 method. The amorphous thermoplastic resin has a Vicat softening temperature of 60°C to 300°C, as measured according to the JIS K 7206 B50 method. The matrix comprises three or more sections, each section exposed on the fiber surface, and / or is formed by melting composite fibers in which one section occupies at least 60% of the outer circumference of the fiber's cross-section. To provide a composite molded body.

[0007] Furthermore, this disclosure relates to a substrate for a composite molded article, comprising reinforcing fibers and composite molded article matrix fibers made of two or more types of thermoplastic resins and including a plurality of sections, The fiber for the composite molded matrix has three or more sections, and each section is exposed on the fiber surface, or one section occupies at least 60% of the outer circumference of the fiber's cross-section. Of the two or more types of thermoplastic resins mentioned above, at least one is a crystalline thermoplastic resin, and at least one is an amorphous thermoplastic resin. The crystalline thermoplastic resin has a Vicat softening temperature of 60°C to 260°C, as measured according to the JIS K 7206 B50 method. The amorphous thermoplastic resin has a Vicat softening temperature of 60°C to 300°C, as measured according to JIS K 7206 B50 method. To provide a substrate for composite molded articles.

[0008] Furthermore, this disclosure relates to a substrate for a composite molded article, comprising reinforcing fibers and composite molded article matrix fibers made of two or more types of thermoplastic resins and including a plurality of sections, The fiber for the composite molded matrix has three or more sections, and each section is exposed on the fiber surface, or one section occupies at least 60% of the outer circumference of the fiber's cross-section. Of the two or more types of thermoplastic resins mentioned above, at least one is a crystalline thermoplastic resin, and at least one is an amorphous thermoplastic resin. The crystalline thermoplastic resin has a Vicat softening temperature of 60°C to 260°C, as measured according to the JIS K 7206 B50 method. The amorphous thermoplastic resin has a Vicat softening temperature measured based on JIS K 7206 B50 method of 60°C or higher and 300°C or lower. Preparing a base material for a composite molded body, and heating the base material for the composite molded body including performing the heating of the base material for the composite molded body such that the resin having the lowest Vicat softening temperature among the thermoplastic resins melts and encapsulates the resin component having the highest Vicat softening temperature, including further applying pressure when heating the base material for the composite molded body, performing the heating and the pressure application such that the density of the composite molded body is 85% or more of the true density, Provided is a method for manufacturing a composite molded body.

[0009] Furthermore, the present disclosure is a composite fiber composed of two or more types of thermoplastic resins and having 3 or more sections, wherein at least one type of the two or more types of thermoplastic resins is a crystalline thermoplastic resin and at least one type is an amorphous thermoplastic resin, the crystalline resin has a Vicat softening temperature measured based on JIS K 7206 B50 method of 60°C or higher and 260°C or lower, the amorphous resin has a Vicat softening temperature measured based on JIS K 7206 B50 method of 60°C or higher and 300°C or lower, Provided is a fiber for a composite molded body matrix in which all sections of the composite fiber are exposed on the fiber surface or one section occupies at least 60% of the outer periphery of the cross-section of the fiber.

Advantages of the Invention

[0010] The composite molded article of this disclosure comprises a matrix formed by melting composite fibers having three or more sections, comprising at least one crystalline thermoplastic resin and at least one amorphous thermoplastic resin. This composite molded article exhibits the properties of both the crystalline and amorphous resins, resulting in excellent mechanical properties such as bending properties, making it suitable for use in a variety of applications. [Brief explanation of the drawing]

[0011] [Figure 1] (a) to (h) are cross-sectional views showing examples of composite configurations of the fibers for the composite molded body matrix of this embodiment. [Figure 2] (a) and (b) are cross-sectional views showing examples of composite configurations of the fibers for the composite molded body matrix of this embodiment. [Figure 3] This graph shows the bending stress-strain curves for Examples 1-1, 1-2, and 1-3. [Figure 4] This graph shows the bending stress-strain curves for Examples 1-4 to 1-7, Comparative Example 1-2, and Comparative Examples 1-4 to 1-6. [Figure 5] This graph shows the bending stress-strain curves for Examples 2-1, 2-4, and Comparative Examples 2-2, 2-4, and 2-7. [Figure 6] This graph shows the bending stress-strain curves for Examples 2-2 and 2-5, and Comparative Examples 2-3, 2-5, and 2-8. [Figure 7] This graph shows the bending stress-strain curves for Examples 2-3 and 2-6, and Comparative Examples 2-6 and 2-9. [Modes for carrying out the invention]

[0012] (Reasons for arriving at this embodiment) Many of the aforementioned patent documents propose, in their examples, the production of a composite molded article by mixing core-sheath type composite fibers made from two or more thermoplastic resins with different melting points with reinforcing fibers and then subjecting a fiber sheet such as a nonwoven fabric to heat and pressurize treatment. However, there is a need for further improvement in the mechanical properties of composite molded articles, especially composite molded articles with thermoplastic resins as a matrix. Furthermore, the technologies disclosed in these patent documents are characterized by either the composition of the thermoplastic resin that forms the matrix itself, the composition of the reinforcing fibers, or the composition of the fiber sheet. These patent documents do not teach the formation of a matrix using composite fibers made from two or more resins belonging to different systems, nor do they teach the influence of the composite morphology of the composite fibers on the composite molded article.

[0013] The inventors hypothesized that by using crystalline thermoplastic resin and amorphous thermoplastic resin to form composite fibers and melting them, a matrix composed of different resin components in a pseudo-alloy-like state derived from the fibers would be formed, unlike conventional polymer alloys, resulting in a unique composite molded article that utilizes the properties of each resin. They also investigated the possibility that the composite morphology of the composite fibers forming the matrix would affect the mechanical properties of the composite molded article. The inventors fabricated composite fibers in combinations of crystalline thermoplastic resin and amorphous thermoplastic resin, each having a Vicat softening temperature within a predetermined range, in which each resin constitutes a section, and the number of sections is three or more, with each section either being exposed on the fiber surface or one section occupying at least 60% of the outer circumference of the fiber's cross-section. They then attempted to form a matrix using these composite fibers.

[0014] As a result, we found that even when the crystalline resin and amorphous resin belong to different systems, such composite fibers are less prone to delamination between sections, and that composite molded articles formed using such composite fibers have improved mechanical properties. Furthermore, we found that even when using composite fibers prone to delamination, by creating a substrate for composite molded articles that does not cause delamination, composite molded articles formed using such composite fibers have improved mechanical properties.

[0015] Furthermore, we found that when at least one type of thermoplastic resin contains a compatibilizer, the mechanical properties of the composite molded article are further improved due to the combination of reduced delamination between sections and improved adhesion between the thermoplastic resin with the compatibilizer and the reinforcing fibers. The following describes the composite molded article matrix fibers, the composite molded article substrate, and the composite molded article of this embodiment, along with their manufacturing methods.

[0016] (Embodiment 1: Fibers for composite molded body matrix and method for manufacturing the same) [Composition of fibers for composite molded matrix] The composite fiber for the composite molded article matrix (hereinafter referred to as "matrix fiber") of this embodiment is a composite fiber having three or more sections, consisting of a combination of two or more thermoplastic resins, where at least one is a crystalline thermoplastic resin (hereinafter referred to as "crystalline resin") and at least one is an amorphous thermoplastic resin (hereinafter referred to as "amorphous resin").

[0017] The composite form of the composite fiber may be one in which each section is exposed on the fiber surface (hereinafter, this composite form will also be conveniently referred to as the "surface-exposed composite form"). An example of this composite form is shown in Figure 1. In all the illustrated forms, each section is composed of one of two types of thermoplastic resins (A or B). In the illustrated forms, adjacent sections are composed of different thermoplastic resins, or a section has multiple linear or petal-like parts extending radially from the center, and a section fills the space between these linear or petal-like parts.

[0018] Figures 1(a) to (h) all show cross-sections perpendicular to the length direction of the fibers (hereinafter referred to as "cross-sections"). The composite forms shown in Figures 1(a) and (g) are arranged in a chrysanthemum pattern with wedge-shaped sections, while Figure 1(h) shows the composite forms shown in Figures 1(a) and (g) with a hollow center. The composite form shown in Figure 1(b) has sections arranged in a striped pattern. The composite forms shown in Figures 1(c) and (d) have a single section from which multiple rod-shaped parts radiate outwards, with other sections placed between the rod-shaped parts. The composite forms shown in Figures 1(e) and (f) can be considered variations of Figure 1(c), with a section having multiple radially extending parts and other sections placed between these parts.

[0019] Composite fibers in a surface-exposed composite form are used, for example, in artificial leather and wipers, as they can provide ultrafine fibers consisting of one or more sections. In contrast, the matrix fibers of this embodiment, by using at least one type of crystalline thermoplastic resin and at least one type of amorphous thermoplastic resin, can be made less prone to delamination between sections even in a surface-exposed composite form, and in that case, ultrafine fibers are less likely to be generated. By adopting a configuration that is less prone to generating ultrafine fibers, the bending properties of the composite molded article can be improved in combination with the melting behavior derived from the adjacent composite fiber structure of each section.

[0020] The matrix fibers of this embodiment are composed of at least one crystalline thermoplastic resin and at least one amorphous thermoplastic resin. The reason why this selection of resins makes delamination between sections less likely is unclear.

[0021] In another embodiment, the matrix fiber may be a composite form having multiple sections, particularly three or more sections, in the cross-section of the fiber, where one section occupies at least 60% of the outer circumference of the fiber's cross-section. Such a composite form makes it easier to provide a configuration in which one section completely covers or wraps around an adjacent section near the outer circumference of the fiber's cross-section, making delamination between sections less likely and reducing the generation of ultrafine fibers. Such a composite form is shown, for example, in Figures 2(a) and (b). Alternatively, in the composite form shown in Figure 2(b), a composite form in which some or all of the tips (the ends furthest from the center of the fiber's cross-section) of the island components formed of resin A are exposed on the fiber surface also makes delamination less likely. In sea-island type composite fibers as shown in Figures 2(a) and (b), making the island components smaller and increasing their number makes it easier to mix two or more types of resin more homogeneously. The following details the combinations of resins.

[0022] Examples of resins constituting the matrix fibers include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate and its copolymers; polyolefin resins such as polypropylene, polyethylene (including high-density polyethylene, low-density polyethylene, linear low-density polyethylene, etc.), polybutene-1, propylene copolymers mainly composed of propylene (including propylene-ethylene copolymers and propylene-butene-1-ethylene copolymers), ethylene-acrylic acid copolymers, and ethylene-vinyl acetate copolymers; polyamide resins such as nylon 6, nylon 12, and nylon 66; acrylic resins; engineering plastics such as polycarbonate resins, polyacetal resins, polystyrene resins, and cyclic polyolefins, as well as elastomers thereof. The matrix fibers are composed of two or more thermoplastic resins selected from these, having a difference in melting point or Vicat softening temperature.

[0023] In this embodiment, at least one of the resins constituting the matrix fibers is a crystalline resin, and at least one is an amorphous resin. In the above, crystalline resins are generally polyester resins, polyolefin resins, polyamide resins, and polyether resins, and amorphous resins are generally polystyrene resins, polycarbonate resins, acrylic resins, and vinyl chloride resins. These classifications are general, and for example, some polyester resins are amorphous. Whether a resin is crystalline or amorphous is determined by the presence or absence of a melting point (whether or not a melting peak is observed in the heat of fusion curve obtained by differential scanning calorimetry (DSC)), solubility in organic solvents, etc.

[0024] Since the matrix fibers of this embodiment include at least one type of amorphous resin, the Vicat softening temperature is used as one of the indicators of the thermal behavior of the resin, instead of the melting point. In this embodiment, the crystalline resin may have a Vicat softening temperature of 60°C to 260°C as measured according to the JIS K 7206 B50 method, and the amorphous resin may have a Vicat softening temperature of 60°C to 300°C as measured according to the JIS K 7206 B50 method.

[0025] Furthermore, in combinations of two resins (for example, in the case of three types of resins A, B, and C, all combinations of AB, AC, and BC), the Vicat softening temperature difference may be 1°C or more, preferably 10°C or more, particularly 20°C or more, and more particularly 30°C or more. Also, the upper limit of the Vicat softening temperature difference may be, for example, 150°C, particularly 120°C, and more particularly 100°C.

[0026] When manufacturing a composite molded article, the substrate for the composite molded article is heated as described later to form a matrix with matrix fibers. The heating should be carried out so that the resin with the lowest Vicat softening temperature among the two or more types of thermoplastic resins melts, but the processing temperature may also be selected considering the Vicat softening temperature of the thermoplastic resin with the highest Vicat softening temperature. When selecting the heating temperature in this way, if the difference in Vicat softening temperatures is too large, the thermoplastic resin with the lowest Vicat softening temperature will be excessively heated, causing the polymer chains of that resin to break and leading to depolymerization, which may degrade one of the physical properties of the composite molded article. Also, if the difference in Vicat softening temperatures is too large, and the heating temperature is selected considering only the melting of the thermoplastic resin with the lowest Vicat softening temperature, the thermoplastic resin with the highest Vicat softening temperature may not melt, and the physical properties of the composite molded article may not be obtained sufficiently.

[0027] The methods for measuring the fiber melting point and the Vicat softening temperature are as follows. [Method for measuring the melting point of fibers] Differential scanning calorimetry (DSC) was performed on the fibers. The melting points of each component were determined using a differential scanning calorimeter (manufactured by Seiko Instruments Inc.), with a fiber quantity (sample amount) of 3.0 mg. The fiber was heated from room temperature to 300°C at a heating rate of 10°C / min to melt it, and the melting points were determined from the resulting heat of fusion curve. [Method for measuring the Vicat softening temperature] The measurement shall be performed according to the method described in JIS K 7206 B50. The Vicat softening temperature shall be measured on the resin before it is fiberized. The test specimen shall consist of the resin alone and shall be 10 mm in length and 10 mm in width.

[0028] Examples of crystalline resin / amorphous resin combinations include polyolefin / polycarbonate, polyolefin / polystyrene, polyamide / polycarbonate, polyamide / polystyrene, polyester / polycarbonate, and polyester / polystyrene.

[0029] In combinations where a polyolefin resin is used as a crystalline resin, the polyolefin resin may be selected from polypropylene, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polymethylpentene, ethylene-propylene copolymer, propylene-ethylene-1-butene ternary copolymer, and modified versions thereof. In combinations where a polyamide resin is used as a crystalline resin, the polyamide resin may be selected from aliphatic polyamides such as polyamide 6 (nylon 6), polyamide 66 (nylon 66), polyamide 610, polyamide 612, polyamide 614, polyamide 11, polyamide 12, polyamide 1010, and polyamide 1012, and semi-aromatic polyamides such as polyamide 6T, polyamide 6I, polyamide 9T, polyamide M5T, polyamide 10T, polyamide MXD6, polyamide 6T / 66, polyamide 6T / 6I, polyamide 6T / 6I / 66, and polyamide 6T / 2M-5T. In combinations where the polyester resin is a crystalline resin, the polyester resin may be selected from polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate, etc. In combinations where the polystyrene resin is a crystalline resin, the polystyrene resin may be syndiotactic polystyrene (SPS).

[0030] In combinations where the polystyrene resin is an amorphous resin, the polystyrene resin may be selected from homopolystyrene (GPPS), high-impact polystyrene (HIPS), isotactic polystyrene (IPS), atactic polystyrene (APS), acrylonitrile butadiene styrene (ABS), etc.

[0031] More specifically, the combination of crystalline resin / amorphous resin may be polypropylene / polycarbonate, polyethylene terephthalate / HIPS, polyamide 6 (nylon 6) / polycarbonate, etc.

[0032] When forming a composite fiber by selecting three or more resins, the other resins may be crystalline or amorphous, as long as they include at least one crystalline resin and at least one amorphous resin. For example, in a combination of three resins A, B, and C, resin A may be selected from polyolefin resins, resin B from polycarbonate, and C from polystyrene resins. Alternatively, resin A may be selected from polyester resins, and resins B and C may be selected from polystyrene resins, each being a different resin. Alternatively, resin A may be selected from polyamide resins, resin B from polycarbonate, and resin C from polystyrene resins. In this case, the other resins may be included in a range that does not impair the properties of at least one crystalline resin and at least one amorphous resin, and when the mass of the composite fiber is 100% by mass, the content of the other resins may be 20% by mass or less, 20% by mass or less, or 5% by mass or less.

[0033] In combinations of two or more thermoplastic resins, a compatibilizer may be mixed with one or more resins. Compatibility with reinforcing fibers and other resins may be improved. The compatibilizer can further enhance the affinity between resins, and may reduce the splitting rate of fibers spun in the above composite form. The matrix fibers of this embodiment can be provided as being less prone to delamination between sections even without mixing in a compatibilizer, but by mixing in a compatibilizer, the integrity of the matrix is ​​further improved, and depending on the type of resin, the adhesion with reinforcing fibers is further improved.

[0034] Of the above combinations, the polyolefin / polycarbonate combination, particularly the polypropylene / polycarbonate combination, is preferred because it allows for the production of fine fibers containing polycarbonate, which has poor stretchability during fiber formation, and because of the difference in Vicat softening temperature. Also, of the above combinations, the polyester / polystyrene combination is preferred because it allows for the production of fine fibers containing polystyrene, which has poor stretchability during fiber formation, and because of the difference in Vicat softening temperature.

[0035] When a compatibilizer is used, it may be either a reactive or non-reactive compatibilizer, but a reactive compatibilizer is particularly preferred. Examples of reactive compatibilizers include adhesive resins in which a polar group (e.g., maleic acid) is introduced into polyolefins (e.g., polypropylene) (e.g., Modic P908 (trade name) from Mitsubishi Chemical Corporation, Yumex 1001 and Yumex 1010 (trade names) from Sanyo Chemical Industries, Ltd., and Rikeaid MG400P (trade name) from Riken Vitamin Co., Ltd.), and ionomer resins in which the intermolecules of ethylene-methacrylic acid copolymers are crosslinked with metal ions (e.g., Hymiran (1702):Zn (trade name) from Mitsui Dow Polychemical Co., Ltd.). Examples of non-reactive compatibilizers include adhesive resins in which the ends of hydrogenated styrene-based thermoplastic elastomers are amine-modified (e.g., ToughTec MP10 (trade name) manufactured by Asahi Kasei Corporation), and hydrogenated styrene-based thermoplastic elastomers of styrene-butadiene random copolymer (e.g., Dynalon (trade name) manufactured by JSR Corporation, Septon (trade name) manufactured by Kuraray Co., Ltd.). The compatibilizers used in this embodiment are not limited to these, and other compatibilizers may be used.

[0036] For example, when constructing matrix fibers using a polypropylene / polycarbonate combination, the compatibilizer may be added only to the polypropylene. In this case, the bending properties and impact resistance of the resulting composite molded article tend to be improved compared to one without a compatibilizer. This is thought to be because adding an olefin resin, into which polar groups such as (maleic anhydride) have been introduced by copolymerization or graft polymerization, to nonpolar polypropylene improves its affinity with polycarbonate, which has ester bonds (polar groups), thus reducing the likelihood of interfacial delamination between the resins. Furthermore, the introduction of polar groups such as (maleic anhydride) is also thought to improve the adhesion between polypropylene and carbon fibers. In other words, it is estimated that the mechanical properties of the composite molded article are improved because polypropylene and polycarbonate melt in a state where interfacial delamination is less likely to occur (a compatibilized state), and the adhesion between the polypropylene with introduced polar groups and carbon fibers is improved.

[0037] The adhesion between reinforcing fibers and the matrix tends to improve significantly when polypropylene is used as the crystalline resin, and maleic acid-modified polypropylene is added only to the polypropylene as a compatibilizer, with carbon fibers used as the reinforcing fibers. This is thought to be because carbon fibers are non-polar, and polypropylene is also non-polar, making it easier to obtain the effect of introducing polar functional groups.

[0038] When selecting thermoplastic resins, their fluidity under heating should also be considered. If there are differences in the fluidity of the thermoplastic resins, it is thought that during the heating and pressurizing process when manufacturing the composite molded product, the resin with higher fluidity will flow first, followed by the resin with lower fluidity. By staggering the flow timing of two or more types of resins, the gaps between reinforcing fibers can be filled more effectively (i.e., the density of the composite molded product can be increased), so resins with different fluidity levels may be selected as needed to constitute the matrix fibers.

[0039] Compatibilizers, especially reactive compatibilizers, may be mixed such that, when the combined mass of the thermoplastic resin (and any additives other than the compatibilizer, if present) and the reactive compatibilizer is taken as 100% by mass, the proportion of the compatibilizer is, for example, 1% to 30% by mass, more particularly 3% to 20% by mass, and more particularly 5% to 15% by mass. When the proportion of the compatibilizer is within this range, it tends to be easier to increase the affinity between resins without inhibiting the expression of the properties of the thermoplastic resin in the matrix.

[0040] When the matrix fibers are composed of two types of thermoplastic resins, a crystalline resin and an amorphous resin, the composite ratio (volume ratio, RH / RL) may be, for example, 20 / 80 to 80 / 20, particularly 25 / 75 to 75 / 25, and more particularly 28 / 72 to 72 / 28, depending on the composite ratio within this range. Alternatively, the composite ratio (RH / RL) of the matrix fibers may be 20 / 80 to 50 / 50, particularly 25 / 75 to 45 / 55, and more particularly 28 / 72 to 40 / 60. By setting the RL ratio to 50 or higher, RL becomes the main component (base) of the matrix, and the moldability of the composite molded article tends to be better.

[0041] When the crystalline / amorphous combination is polypropylene / polycarbonate, polypropylene is RL and polycarbonate is RH. In these combinations, a composite ratio within the above range is particularly preferred from the viewpoint of spinnability and moldability.

[0042] When the crystalline / amorphous combination is polyethylene terephthalate / HIPS, polyethylene terephthalate is RH and HIPS is RL. In these combinations, a composite ratio within the above range is particularly preferred from the viewpoint of spinnability and moldability.

[0043] In a surface-exposed composite matrix fiber, the number of sections is 3 or more, for example, 4 to 32, particularly 6 to 24, and more particularly 8 to 20.

[0044] In the sea-island composite matrix fibers shown in Figures 2(d) and (e), the number of island components may be two or more, particularly three or more, and more particularly four or more. The upper limit of the number of island components may be 200, particularly 150, more particularly 100, or 50, or 30, or 20. When the number of island components is within the above range, the multiple resins tend to be mixed more uniformly or more homogeneously, forming a matrix in which the multiple resins are homogeneously integrated.

[0045] The fineness of the matrix fibers may be, for example, 1.0 dtex to 45 dtex, particularly 1.5 dtex to 30 dtex, more particularly 2.0 dtex to 15 dtex, and more preferably 3.0 dtex to 12.0 dtex. When the fineness of the matrix fibers is within the above range, it tends to be easier to manufacture the nonwoven fabric for the composite molded article together with the reinforcing fibers. If the fineness of the matrix fibers is too low, the spinnability is poor and productivity decreases, and if the fineness of the matrix fibers is too high, voids may occur in the composite molded article.

[0046] The surface-exposed composite matrix fibers may have a fineness such that, assuming each section separates into a single fiber, each section can become, for example, a fiber with a fineness of 1.2 dtex or less, preferably 1.0 dtex or less, and more preferably 0.5 dtex or less. For fibers as shown in Figures 1(c) to (f), the sections located between the radial portions of the central section may have a fineness within the above range. Assuming each section becomes a single fiber, the lower limit of the fineness of the fibers that can be composed of each section is, for example, 0.01 dtex, particularly 0.006 dtex. If one section provides a fiber with a fineness within the above range, each component melts in a finely separated state, making it possible to form a more uniform matrix. Therefore, the fineness of the surface-exposed composite matrix fibers may be appropriately selected, taking into consideration the number of sections.

[0047] The matrix fibers may be continuous or discontinuous, and should be appropriately selected depending on the form of the base material to be produced using them. For example, when producing a card web to make a nonwoven fabric, discontinuous fibers are preferred for the matrix fibers, and their fiber length is preferably 20 mm to 100 mm, more preferably 26 mm to 75 mm, and particularly preferably 30 mm to 65 mm. When producing a wet papermaking web to make a nonwoven fabric, discontinuous fibers are preferred for the matrix fibers, and their fiber length is preferably 2 mm to 20 mm, more preferably 2 mm to 15 mm, and particularly preferably 3 mm to 10 mm. When producing an airlaid web to make a nonwoven fabric, discontinuous fibers are preferred for the matrix fibers, and their fiber length is preferably 2 mm to 100 mm, more preferably 5 mm to 90 mm, particularly preferably 5 mm to 85 mm, and most preferably 8 mm to 80 mm. When forming a sheet by air conveying, the fiber length is preferably 3 mm to 25 mm, more preferably 5 mm to 20 mm.

[0048] [Method for manufacturing fibers for composite molded body matrices] Matrix fibers may be manufactured by a compound spinning method using a conventional melt spinning machine with an appropriate compound spinning nozzle, depending on the composite form. The spinning temperature (nozzle temperature) is selected according to the resin used.

[0049] Specifically, a composite nozzle that obtains a predetermined fiber cross-section is attached to a melt spinning machine, and multiple resins are extruded and melt-spun at a spinning temperature of 200°C to 360°C to obtain spun filaments (undrawn fiber bundles) having fiber cross-sections such as those shown in Figures 1(a) to (h) or Figures 2(a) and (b).

[0050] The fineness of the spun filament (undrawn fiber bundle) may be in the range of 1 dtex to 50 dtex. Spinning becomes easier when the fineness of the spun filament is between 1 dtex and 50 dtex. Preferably, the fineness of the spun filament is between 2.0 dtex and 40 dtex, more preferably between 2.5 dtex and 30 dtex, even more preferably between 3 dtex and 15 dtex, and particularly preferably between 4.0 dtex and 12 dtex. These fineness ranges of the spun filament are preferable, for example, in order to further improve dispersibility when producing wet-laid nonwoven fabrics.

[0051] Next, the spun filament is stretched using a known stretching machine to obtain a stretched filament. The stretching process may be carried out by wet stretching or dry stretching, depending on the type of resin used.

[0052] The stretching ratio is preferably between 1.1 and 10 times. By performing the stretching process at the stretching ratio, the unstretched fibers can be sufficiently stretched, and the resulting matrix fibers will have sufficient single-fiber strength to constitute the nonwoven fabric, as well as the influence of the fiber melting point due to the progression of crystal orientation can be suppressed. The stretching ratio is preferably between 1.1 and 10 times, more preferably between 1.2 and 8 times, particularly preferably between 1.3 and 6.0 times, and most preferably between 1.5 and 5.0 times.

[0053] The resulting drawn filaments are then coated with a predetermined amount of fiber treatment agent as needed, and further mechanical crimping is applied using a crimper (crimping device) as needed. The fiber treatment agent is applied, for example, to suppress the generation of static electricity that occurs during nonwoven fabric manufacturing and to improve carding, or to facilitate the dispersion of fibers in water or the like when manufacturing wet nonwoven fabrics.

[0054] After applying the fiber treatment agent (or while the filament is wet but not yet treated), dry it at a temperature between 80°C and 110°C for a few seconds to about 30 minutes to dry the fibers. This drying process may be omitted if necessary. The filament is then cut to the desired fiber length.

[0055] (Embodiment 2: Substrate for composite molded body and method for manufacturing the same) Next, as Embodiment 2, a substrate for a composite molded article using the matrix fibers of Embodiment 1 and a method for manufacturing the same will be described.

[0056] The substrate of this embodiment includes reinforcing fibers and matrix fibers of Embodiment 1, and in the substrate, the reinforcing fibers and matrix fibers exist in the form of continuous or discontinuous fibers, respectively. The substrate is provided, for example, as a sheet, a plate, a composite yarn, or a three-dimensional structure formed into a predetermined shape. The sheet may be, for example, paper, woven fabric, knitted fabric, mesh, net, mat or nonwoven fabric, or a combination thereof. The sheet may also be in the form of a laminate, in which case the laminated sheets may be the same or different from each other.

[0057] [Nonwoven fabric for composite molded bodies] The base material of this embodiment may be a nonwoven fabric for composite molded articles (hereinafter sometimes simply referred to as "nonwoven fabric"), in which case the base material includes reinforcing fibers and matrix fibers of Embodiment 1. The reinforcing fibers are not particularly limited as long as they are commonly used as reinforcing fibers for composite molded articles, and may be high-strength fibers such as glass fibers, aramid fibers, or carbon fibers. Since high fiber strength can increase the strength of the composite molded article, they are preferably used in composite molded articles used in applications where strength is important. Carbon fibers are lightweight and have superior specific strength and specific modulus compared to glass fibers and aramid fibers, making them suitable for use as reinforcing fibers in composite molded articles where lightness is desired. Aramid fibers have excellent heat resistance and chemical resistance, as well as superior mechanical strength such as tensile strength, modulus of elasticity, and shock absorption.

[0058] The fineness of the reinforcing fiber may be, for example, 0.1 dtex or more and 20 dtex or less, particularly 0.2 dtex or more and 10 dtex or less, and more particularly 0.3 dtex or more and 5 dtex or less. Alternatively, the fiber diameter of the reinforcing fiber may be, for example, 1 μm or more and 40 μm or less, particularly 2 μm or more and 20 μm or less, and more particularly 3 μm or more and 15 μm or less. If the reinforcing fiber is a carbon fiber, the preferred fiber diameter is 3 μm or more and 10 μm or less. If the reinforcing fiber is an aramid fiber, the preferred fiber diameter is 3 μm or more and 15 μm or less.

[0059] The longer the reinforcing fiber, the better the reinforcing effect it provides. Therefore, if the reinforcing fiber is too short (for example, less than 1 mm), it is difficult to obtain sufficient reinforcing effect. In particular, since fibers with a length of less than 1 mm are in powder form, problems such as the reinforcing fiber falling off may occur in nonwoven fabrics made using such fibers.

[0060] The fiber length of the reinforcing fibers is appropriately selected depending on the form of the nonwoven fabric to be produced. For example, when producing a nonwoven fabric by making a card web, the fiber length of the reinforcing fibers is preferably 20 mm to 70 mm, more preferably 25 mm to 52 mm. When producing a nonwoven fabric by making a wet papermaking web, the fiber length of the reinforcing fibers is preferably 3 mm to 25 mm, more preferably 5 mm to 20 mm. When producing a nonwoven fabric by making an airlaid web, the fiber length of the reinforcing fibers is preferably 20 mm to 70 mm, more preferably 25 mm to 52 mm, when sheeting is done in combination with a carding machine. When sheeting is done by pneumatic conveying, the fiber length is preferably 3 mm to 25 mm, more preferably 5 mm to 20 mm.

[0061] The reinforcing fibers may be mixed in such a way that, when the total volume of fibers constituting the nonwoven fabric is taken as 100%, the proportion of reinforcing fibers is, for example, 20% to 60% by volume. The proportion of reinforcing fibers may be particularly 25% to 55% by volume. In particular, if the reinforcing fibers are carbon fibers, the reinforcing fibers may be mixed in such a way that, when the total volume of fibers constituting the nonwoven fabric is taken as 100%, the proportion of carbon fibers is, for example, 20% to 50% by volume. The proportion of carbon fibers may be particularly 25% to 40% by volume. The fibers other than the reinforcing fibers in the nonwoven fabric (the remainder) may be the matrix fibers described in Embodiment 1, or, in addition to the matrix fibers described in Embodiment 1, other matrix fibers or other fibers may be included. It is preferable that the other matrix fibers or other fibers are composed only of thermoplastic resin. Even when other matrix fibers are included, the proportion of matrix fibers described in Embodiment 1 is preferably 40% or more by volume, more preferably 50% or more by volume, and even more preferably 60% or more by volume. If other matrix fibers are included, their proportion is preferably 30% by volume or less, and more preferably 20% by volume or less. If the proportion of matrix fibers in Embodiment 1 is small, the effects of using these matrix fibers may not be obtained in the composite molded article manufactured using this nonwoven fabric.

[0062] The basis weight of the nonwoven fabric depends on the desired thickness of the composite molded product, for example, 10 g / m². 2 More than 12000g / m 2 The following is often used, especially 500g / m² 2 More than 3600g / m 2 The following is acceptable. The composite molded article has a density of, for example, 1000 g / m². 2 The material may be provided with the above basis weight. When laminating multiple nonwoven fabrics to obtain such a composite molded product, if the basis weight of the nonwoven fabric is small, it may be necessary to laminate a large number of nonwoven fabrics, which can complicate the manufacturing of the composite laminate. On the other hand, if the basis weight of the nonwoven fabric is large, inconsistencies may occur in the fiber density and fiber mixing state, which may lead to problems such as a decrease in the uniformity of the composite molded product.

[0063] In nonwoven fabrics, the fibers may or may not be adhered to each other by some of the matrix fibers. Furthermore, the fibers constituting the nonwoven fabric may be entangled with each other through mechanical entanglement treatment (e.g., needle punching, high-pressure fluid flow treatment). Alternatively, if the nonwoven fabric is made from, for example, a wet-machine papermaking web, it may not be subjected to mechanical entanglement treatment, but rather be integrated by the entanglement of fibers that occurs during papermaking (generally less pronounced than entanglement caused by mechanical entanglement treatment). Nonwoven fabrics manufactured without mechanical entanglement treatment, when using matrix fibers in a surface-exposed composite form, exhibit more suppressed fiber splitting, potentially resulting in a composite molded body with improved mechanical properties.

[0064] The nonwoven fabric may contain fibers other than the matrix fibers described in Embodiment 1 (hereinafter referred to as "other fibers"). These other fibers may be, for example, single fibers made of the thermoplastic resin exemplified in Embodiment 1. If other fibers are included, they shall be present in a proportion of 30% by mass or less, more particularly 20% by mass or less, and more particularly 10% by mass or less, when the total mass of the fibers constituting the nonwoven fabric is taken as 100% by mass. The other fibers may, together with the matrix fibers, constitute the matrix of the composite molded product. For example, if the other fibers are single fibers made of polypropylene and the matrix fibers are composite fibers made of a combination of polypropylene and polycarbonate, the other fibers may constitute the matrix.

[0065] The matrix fibers used in this embodiment may be provided in a manner that makes delamination less likely to occur between sections, as described in Embodiment 1, and in that case, it is less likely to generate ultrafine fibers consisting of one or more sections. Therefore, in a nonwoven fabric using the matrix fibers described in Embodiment 1, the proportion of ultrafine fibers on the surface of the nonwoven fabric, measured by the following method, may be less than 20%, particularly 10% or less, more particularly 5% or less, and even more particularly 1% or less. The lower limit of the proportion of ultrafine fibers may be, for example, 2%, particularly 1%, and more particularly 0.5%. A small proportion of ultrafine fibers on the surface of the nonwoven fabric means that the affinity between the resins in the matrix fibers is high, and when a composite molded article is formed, delamination is less likely to occur at the resin interface in the matrix, improving the mechanical properties of the molded article. <Method for measuring the proportion of ultrafine fibers on the surface of nonwoven fabric> (1) Observe the surface of the substrate under an electron microscope at 200x magnification, and take a photograph of the magnified surface. (2) Count the number of fibers present in the captured image that are for the composite molded matrix and have a length of 200 μm or more, and the number of fibers derived from the composite molded matrix. Of these, fibers that are 150 μm or more in the fiber length direction and have a fiber diameter of less than 1 / 2 are defined as ultrafine fibers. (3) The proportion of ultrafine fibers is determined using the following formula. Percentage of ultrafine fibers expressed (%) = (Number of ultrafine fibers / Number of fibers for composite molded matrix) × 100

[0066] Alternatively, the nonwoven fabric for the composite molded article of this embodiment may be a nonwoven fabric having a splitting rate of matrix fibers in the nonwoven fabric of 30% or less, particularly 20% or less, more particularly 10% or less, and even more particularly 5% or less, as measured by the following method. The splitting rate may be even more particularly 1% or less, and most preferably 0%. <Method for measuring the splitting ratio of matrix fibers in nonwoven fabrics> (1) Bundle the substrates so that as little space as possible is created, and cut them to expose the cross-sections so that the fiber cross-sections of the composite mold matrix fibers can be observed. (2) Observe the cross-section by magnifying it 400 to 600 times with an electron microscope, and take a photograph of the magnified cross-section. (3) From the captured images, select the split fibers from among the fibers derived from the composite molded matrix (unsplit fibers and split fibers). Count the number of sections of the split fibers and the number of sections of the unsplit fibers. Unsplit fibers: Fibers having a cross-sectional area that is 1 / 2 or more the cross-sectional area of ​​a completely unsplit fiber. Split fibers: Fibers with a cross-sectional area smaller than half the cross-sectional area of ​​a completely unsplit fiber. (4) The splitting ratio is calculated using the following formula. Splitting rate (%) = [Number of sections of split fibers / (Number of sections of split fibers + Number of sections of unsplit fibers)] × 100

[0067] The above-mentioned splitting ratio also serves as an indicator of the extent to which delamination occurs between sections of matrix fibers, especially fibers in surface-exposed composite forms. A higher splitting ratio indicates that delamination is occurring between sections in more matrix fibers. Nonwoven fabrics with more delamination between sections tend to have lower affinity between resins, and the mechanical properties, particularly bending properties, of composites made using such fabrics tend to be reduced.

[0068] When using matrix fibers in a composite form where one section occupies, for example, 60% or more, especially 80% or more, or even 100% of the outer circumference of the fiber's cross-section, rather than a surface-exposed composite form, the proportion of ultrafine fibers and the splitting rate can both be 20% or less, and may even be 0 percent (or a few percent or less). In such composite forms, if no compatibilizer is added to any section, the affinity between the resins decreases, yet one or more mechanical properties of the resulting composite molded article tend to improve. The improvement in the mechanical strength of the composite molded article, even without the use of a compatibilizer, is thought to be due to the uniform mixing of each component because the resin melts without separation between sections due to the composite form, etc.

[0069] The proportion of ultrafine fibers and the splitting rate are also affected by the form of the base material. For example, by using textile products manufactured without actively splitting fibers, such as long-fiber nonwovens (e.g., spunbond nonwovens), meltblown nonwovens, air-laid nonwovens, dry-laid nonwovens produced by the carding method, and woven fabrics, the proportion of ultrafine fibers or the splitting rate can be reduced.

[0070] [Method for manufacturing base materials for composite molded articles] Next, as an example of a method for manufacturing a substrate for a composite molded article, we will explain a method for manufacturing a nonwoven fabric for a composite molded article. Nonwoven fabrics can be manufactured by conventional methods, by creating a fiber web using reinforcing fibers and matrix fibers, and then bonding and / or entanglement the fibers to integrate them. The form of the fiber web is not particularly limited and may be any form selected from card webs such as parallel webs, cross webs, semi-random webs and random webs, airlaid webs, wet papermaking webs, meltblown webs, and spunbond webs.

[0071] In this embodiment, airlaid webs, cross webs, or wet-machined paper webs are preferably used because they have random fiber orientation and small differences in strength and elongation between the longitudinal and transverse directions.

[0072] In the manufacture of nonwoven fabrics, the method for integrating the fibers of a fiber web is not particularly limited. For example, fiber integration may be performed by a needle punching method and a mechanical entanglement method such as a water jet entanglement method. With the needle punching method, even if the basis weight of the fiber web is large, the fibers can be entangled relatively easily. For example, when a fiber web is made by needle punching, if the basis weight of the fiber web is, for example, 100 g / m² 2 ~12000g / m 2 For this type of situation, use a hook size 36-42 with 3-9 barbs, set the hook depth to 3-20mm, and fish spawn at a rate of 10-500 fish / cm. 2 It is acceptable to perform the work by drilling at this density.

[0073] Alternatively, when producing a papermaking web, the integration of fibers may occur due to the entanglement of fibers during the papermaking and drying processes.

[0074] Alternatively, at least one component constituting the matrix fibers may be softened or melted, and the fibers may be heat-bonded together to form a single unit. In this case, it is preferable to soften and bond only the component with the lowest Vicat softening temperature. Heat bonding may be carried out using, for example, a hot air penetration type heat treatment machine (also called an air-through type heat processing machine), a hot air blowing type heat treatment machine, an infrared type heat treatment machine, or a heat roll processing machine.

[0075] The fineness and fiber length of the fibers constituting the nonwoven fabric are selected according to the form of the fiber web, etc. Exemplary ranges for the fiber lengths of the reinforcing fibers and matrix fibers are as previously described. In any fiber web fabrication, the fiber length of the reinforcing fibers may be the same as or different from that of the matrix fibers. Exemplary finenesses for the reinforcing fibers and matrix fibers are also as previously described; the fineness of the reinforcing fibers may be the same as or different from that of the matrix fibers.

[0076] The nonwoven fabric may be made by laminating two or more fiber webs. In this case, one or more fiber webs may consist of reinforcing fibers, and one or more other fiber webs may consist of matrix fibers. The two or more fiber webs may be made by the same method, or they may be made by different methods (for example, a combination of a card web and a wet-machine web).

[0077] To increase the basis weight of the nonwoven fabric, two or more identical or different fiber webs may be laminated and subjected to a process that integrates the fibers (for example, a fiber entanglement process such as needle punching). In particular, if it is difficult to manufacture fiber webs with a large basis weight, a nonwoven fabric with a large basis weight can be manufactured relatively easily by laminating fiber webs. Alternatively, a fiber web or a nonwoven fabric made from a fiber web may be layered with another nonwoven fabric, woven fabric, knitted fabric, or film, and then subjected to a fiber entanglement process such as needle punching to produce a fiber sheet for manufacturing a composite molded body.

[0078] The nonwoven fabric of this embodiment is formed by mixing reinforcing fibers with composite fibers made of two or more types of thermoplastic resins, where at least one of the thermoplastic resins is a crystalline resin and at least one is an amorphous resin. In particular, when delamination between sections is unlikely to occur in the composite fibers, it is easier to provide the reinforcing fibers and two or more types of thermoplastic resins in a form in which they are uniformly mixed. Therefore, when a composite molded article is manufactured using a nonwoven fabric with this configuration, it is thought that the multiple thermoplastic resins are uniformly dispersed to form a matrix, making it possible to obtain the properties of each thermoplastic resin in a good balance.

[0079] (Embodiment 3: Composite molded article and method for manufacturing the same) Next, Embodiment 3 will describe a composite molded article and a method for manufacturing the same.

[0080] [Composite molded body] The composite molded article of this embodiment includes reinforcing fibers and two or more thermoplastic resins having a difference in melting point or Vicat softening temperature as a matrix, wherein the matrix is ​​formed by the melting of matrix fibers. The reinforcing fibers are as described in relation to Embodiment 2, and the fibers forming the matrix are as described in relation to Embodiment 1.

[0081] In the composite molded article of this embodiment, the flexural modulus of the composite molded article, measured in accordance with Method A (bending test method by three-point bending) of JIS K 7074:1998 (Bending test method for carbon fiber reinforced plastics), is preferably 8 GPa or higher, more preferably 10 GPa or higher, even more preferably 12 GPa or higher, and still more preferably 15 GPa or higher. A composite molded article with a flexural modulus within the above range is preferably used in applications where rigidity is important.

[0082] In the composite molded article of this embodiment, the bending strength of the composite molded article measured in accordance with Method A (bending test method by three-point bending) of JIS K 7074:1998 (Bending test method for carbon fiber reinforced plastics) is preferably 130 MPa or more, more preferably 170 MPa or more, even more preferably 200 MPa or more, and even more preferably 230 MPa or more. A composite molded article with a bending strength within the above range is preferably used in applications where strength is required.

[0083] The above preferred range is an example given considering the general uses of composite molded articles, and the excellent properties of the composite molded article of this embodiment are not determined solely by the absolute values ​​of the mechanical properties. The composite molded article of this embodiment has improved mechanical properties compared to 1) a composite molded article in which the matrix is ​​formed using fibers made of two or more types of thermoplastic resins, at least one of which is crystalline and at least one type is amorphous, in such a way that delamination between sections is less likely to occur, and these are melted to form a matrix. In other words, the excellent mechanical properties of the composite molded article of this embodiment may be demonstrated by such a comparison.

[0084] In this embodiment, the composite molded article may contain reinforcing fibers in a proportion of, for example, 20% to 60% by volume, particularly 25% to 55% by volume, and thermoplastic resin in a proportion of, for example, 40% to 80% by volume, particularly 45% to 75% by volume. In particular, if the reinforcing fibers are carbon fibers, they may be contained in a proportion of 20% to 50% by volume, particularly 25% to 40% by volume, and thermoplastic resin in a proportion of 50% to 80% by volume, particularly 60% to 75% by volume. If the proportion of reinforcing fibers is too low, the effect of mechanical improvement of the composite molded article by the reinforcing fibers may not be obtained, and if the proportion of reinforcing fibers is too high, the proportion of matrix in the composite molded article will be low, and when manufacturing the composite molded article, the matrix may not be able to sufficiently fill the spaces between the reinforcing fibers, increasing voids and reducing the density of the composite molded article, which may lead to a decrease in mechanical properties.

[0085] The composite molded article of the present invention is provided, for example, as a sheet, a plate, or a three-dimensional structure molded into a predetermined shape.

[0086] The thickness and basis weight of the sheet-like or plate-like composite body are appropriately selected according to its use and the like, and are not particularly limited. For example, the thickness is 0.3 mm or more and 10 mm or less, and the basis weight is 400 g / m 2 or more and 12000 g / m 2 or less. A sheet-like composite body containing a thermoplastic resin as a matrix resin can be provided as a stampable sheet that can be formed into another shape by heating and pressing. The forming of the stampable sheet is sometimes called stamping forming.

[0087] The sheet-like composite body may be manufactured from the non-woven fabric described in Embodiment 2. When manufacturing the composite body from the non-woven fabric, depending on the temperature and pressure applied to the matrix fibers, a part of the section constituting the matrix fibers may not completely melt, and in the composite body, a part of the section constituting the matrix fibers may exist while maintaining the fiber shape to some extent.

[0088] In a composite body in which the matrix fibers are not completely melted, since the voids between the reinforcing fibers are not completely filled with the thermoplastic resin, the density is lower compared to the density (true density) of a composite body in which the matrix fibers are completely melted and solidified. Such a composite body has voids, and thus exhibits high impact resistance due to these voids, but tends to be inferior in other mechanical properties (especially bending properties). Therefore, the composite body of the present embodiment may have a density of, for example, 85% or more, particularly 90% or more, more particularly 92% or more, and even more particularly 95% or more of its true density. Although it is ideal for the composite body to be formed with the true density, it may have a density of, for example, 99.5% or less.

[0089] The true density of the composite body can be calculated from the density of the material itself constituting the composite body and the ratio (volume ratio) of the material occupied in the composite body. Specifically, when the matrix fibers are composed of resin 1 and resin 2, the true density can be obtained by the following formula.

Equation

[0090] For example, if a composite molded body consists of 30% by volume of carbon fiber as reinforcing fibers and 70% by volume of composite fibers consisting of a polypropylene / polycarbonate combination with a composite ratio of 7:3 (polypropylene:polycarbonate) as matrix fibers, then the true density is 1.24 g / cm³. 2 (The density of carbon fiber is 1.80 g / cm³) 2 The density of polypropylene is 0.91 g / cm³. 2 The density of the polycarbonate is 1.20 g / cm³. 2 (This is the value calculated as follows.)

[0091] The composite molded body of this embodiment may be provided as a three-dimensional structure processed into a predetermined shape. The three-dimensional structure may be, for example, a nonwoven fabric of Embodiment 2 that is three-dimensionally molded when heated and pressurized, or a sheet-like composite molded body (stampable sheet) that is three-dimensionally molded. Alternatively, the three-dimensional structure may be obtained by cutting a block of the composite molded body to a predetermined shape.

[0092] [Method for manufacturing composite molded articles] The composite molded article of this embodiment can be manufactured, for example, using the nonwoven fabric described in Embodiment 2. Specifically, the composite molded article of this embodiment is To prepare the nonwoven fabric for the composite molded body of Embodiment 2, and Heating nonwoven fabric for composite molded products A manufacturing method including, The heating of the substrate for the composite molded body is carried out such that the resin with the lowest Vicat softening temperature among the two or more thermoplastic resins melts and encapsulates the resin component with the highest melting point or Vicat softening temperature. This includes further pressurizing the nonwoven fabric for composite molded products when heating it. The heating and pressurizing are carried out so that the density of the composite molded body becomes 85% or more of the true density. It can be manufactured by a specific manufacturing method.

[0093] When using the nonwoven fabric of Embodiment 2, depending on the basis weight of the composite molded article to be obtained, multiple layers of the nonwoven fabric may be laminated, and the laminated nonwoven fabric may be subjected to heating and pressurizing treatment.

[0094] The heating and pressurizing processes can be described as steps that composite the reinforcing fibers with the thermoplastic resin (matrix). During the composite process, the thermoplastic resin is melted or softened by heating, allowing it to permeate the voids between the reinforcing fibers and fill the voids with resin. In this embodiment, by simultaneously performing pressurizing, the penetration of the thermoplastic resin into the voids between the reinforcing fibers is further promoted, thereby improving the density of the composite molded article.

[0095] In the manufacturing method of this embodiment, heating and pressurizing are performed so that the density of the resulting molded article is preferably 85% or more, more preferably 90% or more, even more preferably 92% or more, and most preferably 95% or more of its true density. Therefore, the heating and pressurizing are performed under conditions that allow the thermoplastic resin constituting the matrix fibers to have sufficient fluidity and that the fluid thermoplastic resin to sufficiently penetrate into the voids between the reinforcing fibers.

[0096] The heating may be carried out such that, among two or more thermoplastic resins, the resin with the lowest molten Vicat softening temperature melts and encapsulates the resin component with the highest Vicat softening temperature.

[0097] The heating of the composite molded base material is preferably carried out at a temperature of (VST+20)°C or higher and (VST+150)°C or lower, where the resin with the lowest Vicat softening temperature among the two or more thermoplastic resins melts, and the Vicat softening temperature of the thermoplastic resin with the highest Vicat softening temperature is VST°C.

[0098] The heating temperature may be particularly (VST+25)°C or higher and (VST+130)°C or lower, more particularly (VST+30)°C or higher and (VST+110)°C or lower, even more preferably (VST+35)°C or higher and (VST+100)°C or lower, and most preferably (VST+40)°C or higher and (VST+90)°C or lower.

[0099] The Vicat softening temperature of amorphous resins is the temperature of the heat transfer medium when a needle-shaped indenter penetrates 1 mm from the surface of a test specimen made solely of resin, under a specified test load, and the heat transfer medium is heated at a constant rate. This temperature can be measured by the method described in JIS K 7206 B50.

[0100] When the thermoplastic resin with the highest Vicat softening temperature among the resins constituting the matrix fibers is a crystalline resin, the heating temperature may be (Tm-60)°C or higher and (Tm+100)°C or lower, with Tm°C being the melting point of the crystalline resin, more preferably (Tm-55)°C or higher and (Tm+80)°C or lower, even more preferably (Tm-50)°C or higher and (Tm+60)°C or lower, even more preferably (Tm-45)°C or higher and (Tm+50)°C or lower, and most preferably (Tm-40)°C or higher and (Tm+30)°C or lower.

[0101] Here, the melting point of the crystalline resin contained in the matrix fibers is the melting point of the thermoplastic resin in the state of matrix fibers (i.e., the melting point after spinning), and can be measured by differential operating calorimetry (DSC). Specifically, based on JIS K 7121 (1987) Method for Measuring Transition Temperatures of Plastics, a differential scanning calorimeter (manufactured by Seiko Instruments Inc.) is used, with a fiber quantity (sample quantity) of 3.0 mg, and the temperature is raised from room temperature to 300°C at a heating rate of 10°C / min to melt the fibers, and the melting point can be determined from the resulting heat of fusion curve. If multiple peaks appear, Tm is determined from the peak that appears at the highest temperature among the multiple peaks, and the heating temperature is set accordingly.

[0102] If the matrix fibers consist of, for example, a polypropylene / polycarbonate combination, the heating temperature may be 180°C to 270°C, particularly 190°C to 260°C, more particularly 200°C to 250°C, even more preferably 210°C to 240°C, and most preferably 215°C to 235°C. If the matrix fibers consist of, for example, a high-impact polystyrene / polyethylene terephthalate combination, the heating temperature may be 200°C to 270°C, particularly 205°C to 265°C, more particularly 210°C to 260°C, even more preferably 215°C to 250°C, and most preferably 220°C to 240°C.

[0103] The pressure applied during pressurization is appropriately selected considering the fluidity of the thermoplastic resin constituting the fibers, for example, it may be between 1 MPa and 50 MPa, more particularly between 3 MPa and 30 MPa, and more particularly between 5 MPa and 20 MPa. If the resin constituting the matrix fibers includes a resin with low fluidity, the pressure is selected so as to sufficiently promote the flow of that resin.

[0104] If there are differences in the fluidity of thermoplastic resins, it is thought that during heating and pressurizing treatment, the more fluid resin will flow first to fill the gaps between the reinforcing fibers, followed by the less fluid resin. By staggering the flow timing of two or more types of resins, the gaps between the reinforcing fibers can be filled more effectively, bringing the density of the molded product closer to its true density. Therefore, resins with different fluidity levels may be selected as needed to constitute the matrix fibers.

[0105] During the pressurization process, the time for which the nonwoven fabric for the composite molded body is heated and pressurized (high-pressure holding time) may be, for example, 1 second to 600 seconds, particularly 30 seconds to 240 seconds, and more particularly 60 seconds to 200 seconds, depending on the type of reinforcing fiber and matrix fiber used. By keeping the time for which the nonwoven fabric for the composite molded body is heated and pressurized within the above range, a composite molded body close to its true density can be obtained.

[0106] The high-pressure holding time does not include the time spent lowering either the heating temperature or the pressure. For example, if a heated and pressurized state is maintained at a predetermined heating temperature and pressure for a predetermined time, and then the temperature is lowered while the pressure remains the same, the time spent lowering the temperature is not included in the high-pressure holding time.

[0107] Heating and pressurizing may be carried out using an apparatus capable of performing heating and pressurizing simultaneously, such as a hot press. Alternatively, the heating treatment may be performed first, followed by pressurizing while the thermoplastic resin is in a molten or softened state. Such heating and pressurizing are also included in the phrase "further pressurizing when heating the nonwoven fabric for the composite molded article" in the outline of the manufacturing method of this embodiment described above.

[0108] According to this embodiment, a sheet-like composite molded body can be obtained, or a three-dimensional composite molded body can be obtained by imparting a three-dimensional shape during heat treatment and / or pressurization treatment. The sheet-like composite molded body (stampable sheet) can be further subjected to a heat press treatment to create a shape with irregularities. In that case, multiple sheet-like composite molded bodies may be stacked and heat pressed to obtain a thicker composite molded body.

[0109] The method for manufacturing a composite molded article described herein is one form of manufacturing a composite molded article, and it goes without saying that composite molded articles may be manufactured by other methods depending on their shape. For example, a sheet-like composite molded article may be manufactured by applying another thermoplastic resin, which has been melted by impregnation or coating, to a fiber sheet consisting of matrix fibers and reinforcing fibers. In this method, if the Vicat softening temperature of the other thermoplastic resin is higher than that of the thermoplastic resin constituting the matrix fibers with the highest Vicat softening temperature, the matrix fibers are melted when the thermoplastic resin is applied. If the Vicat softening temperature of the other thermoplastic resin is lower than that of the thermoplastic resin constituting the matrix fibers with the highest Vicat softening temperature, the matrix fibers are melted by heating and pressurizing after the application of the other thermoplastic resin. If the fiber sheet is a woven or knitted fabric, the constituent yarn may be any of the following: a blended yarn, a blended twisted yarn, a core yarn, or a covered yarn, consisting of matrix fibers and reinforcing fibers.

[0110] (Applications of composite molded products) The composite molded articles of this embodiment can be used as materials for space and aircraft, ships, vehicles (including automobiles and bicycles), sporting goods, office automation equipment, electronic equipment, industrial materials, tanks and containers, general merchandise, and construction materials. In particular, when carbon fiber is used as the reinforcing fiber, its lightweight properties make it preferably used as interior and exterior materials for aircraft. [Examples]

[0111] The following thermoplastic resins and reactive compatibilizers were prepared. <Thermoplastic resin> • Polypropylene (PP): SA03A (product name) manufactured by Nippon Polypropylene Co., Ltd. Melting point 163°C. Vicat softening temperature 106°C. MFR measured at 21.18N (2.16kgf) in accordance with JIS K 7210 is 30g / 10min (230°C). • Polycarbonate (PC): Yupiron (product name) H4000, manufactured by Mitsubishi Engineering Plastics Corporation. Vicat softening temperature: 144°C. MFR (Moisture Fuel Rate) measured at a load of 11.77N (1.2kgf) according to JIS K 7210: 63g / 10min (300°C). • Polyethylene terephthalate: Manufactured by Kolon. Vicat softening temperature: 179°C. Intrinsic viscosity (IV value): 0.66. • High-impact polystyrene (HIPS): Manufactured by PS Japan Co., Ltd., product name H9152. Vicat softening temperature: 95.8°C. MFR measured at a load of 49.03N (5.0kgf) according to JIS K 7210: 5.5g / 10min (200°C). • Polyamide MXD10: LEXTER (product name) S8501 manufactured by Mitsubishi Gas Chemical Company, Inc. Melting point 213°C. MFR was 13 g / 10 min (230°C) when measured under a load of 21.18 N (2.16 kgf) in accordance with JIS K 7210.

[0112] <Reactive compatibilizer> • Modified polypropylene (adhesive resin in which maleic acid has been introduced into polypropylene): Modic P908 (trade name) manufactured by Mitsubishi Chemical Corporation. Melting point 150℃, MFR 45g / 10min (180℃) measured according to ISO R-1133 with a load of 21.2N (2.16kgf), acid value 12.8.

[0113] [Manufacturing of matrix fiber 1] As shown in Figure 1(g), a composite fiber with a cross-section having wedge-shaped sections arranged in a chrysanthemum pattern and 16 sections was manufactured as matrix fiber 1. First, polypropylene, a crystalline resin, and polycarbonate, an amorphous resin, were melt-spun using a split-fiber type composite fiber nozzle that gives the above composite form, at spinning temperatures of 270°C and 290°C, respectively, to obtain spun filaments with a fineness of 10 dtex. During melt spinning, the discharge amount of each resin was adjusted so that the composite ratio was 7:3 (PP:PC). Next, the spun filaments were subjected to dry stretching at 150°C with a stretching ratio of 1.3 to a fineness of approximately 7.1 dtex, after which a fiber treatment agent was applied and the fibers were cut to a length of 6 mm.

[0114] [Manufacturing of matrix fiber 2] The composite fibers were manufactured using the same procedures and conditions as for the production of matrix fiber 1, except that polypropylene with a 10% by mass reactive compatibilizer added was used instead of polypropylene, and the fibers were cut to a length of 6 mm. The fineness of matrix fiber 2 was 6.9 dtex.

[0115] [Manufacturing of matrix fiber 3] Except for setting the fineness of the spun filament to 6.5 dtex and the draw ratio to 1.2 times, the composite fiber was manufactured using the same procedure and conditions as the manufacturing of matrix fiber 1, and then cut to a fiber length of 6 mm. The fineness of matrix fiber 3 was 5.1 dtex.

[0116] [Manufacturing of matrix fibers 4] A composite fiber having a cross-section with wedge-shaped sections arranged in a chrysanthemum pattern, as shown in Figure 1(g), and with 16 sections, was manufactured as matrix fiber 4. First, polyethylene terephthalate, a crystalline resin, and high-impact polystyrene, an amorphous resin, were melt-spun using a split-fiber type composite fiber nozzle that gives the above composite form, at spinning temperatures of 310°C and 280°C, respectively, to obtain spun filaments with a fineness of 12.4 dtex. During melt spinning, the discharge amount of each resin was adjusted so that the composite ratio was 1:2 (PET:HIPS). Next, the spun filaments were subjected to a wet stretching treatment at 60°C with a stretching ratio of 1.7 times to obtain a fineness of approximately 11.2 dtex, after which a fiber treatment agent was applied and the fibers were cut to a length of 6 mm.

[0117] [Manufacturing of matrix fiber 5] Except for setting the composite ratio to 3:7 (PET:HIPS), the composite fibers were manufactured using the same procedures and conditions as those used for manufacturing matrix fiber 4, and then cut to a fiber length of 6 mm. The fineness of matrix fiber 5 was 10.9 dtex.

[0118] [Manufacturing of matrix fiber 6] A single fiber, in which no more than two sections were observed in the fiber cross-section, was manufactured as matrix fiber 6. Polypropylene was melt-spun using a single-fiber nozzle to obtain a spun filament with a fineness of 6 dtex. Subsequently, the spun filament was subjected to a wet stretching treatment at 90°C with a stretching ratio of 3 to obtain a fineness of approximately 2.2 dtex, after which a fiber treatment agent was applied and the fiber was cut to a length of 6 mm.

[0119] [Manufacturing of matrix fiber 7] A single fiber, in which no more than two sections were observed in the fiber cross-section, was manufactured as matrix fiber 7. Polypropylene containing 10% by mass of a compatibilizer was melt-spun using a single-fiber nozzle to obtain a spun filament with a fineness of 6.0 dtex. Subsequently, the spun filament was subjected to a wet stretching treatment at 90°C with a stretching ratio of 3 to obtain a fineness of approximately 2.2 dtex, after which a fiber treatment agent was applied and the fiber was cut to a length of 6 mm.

[0120] [Manufacturing of matrix fiber 8] A single fiber, in which no more than two sections were observed in the fiber cross-section, was prepared as matrix fiber 8. Polycarbonate was melt-spun using a single-fiber nozzle to obtain spun filaments with a fineness of 7.8 dtex. A fiber treatment agent was applied, and the fibers were cut to a length of 6 mm.

[0121] [Manufacturing of matrix fibers 9] A single fiber, in which no more than two sections were observed in the fiber cross-section, was manufactured as matrix fiber 9. Polyethylene terephthalate was melt-spun using a single-fiber nozzle to obtain a spun filament with a fineness of 20 dtex. Subsequently, the spun filament was subjected to a wet stretching treatment at 55°C with a stretching ratio of 1.7 to obtain a fineness of approximately 10 dtex, after which a fiber treatment agent was applied and the fiber was cut to a length of 6 mm.

[0122] [Manufacturing of matrix fibers 10] A single fiber, in which no more than two sections were observed in the fiber cross-section, was prepared as the matrix fiber 10. High-impact polystyrene was melt-spun using a single-fiber nozzle to obtain spun filaments with a fineness of approximately 10 dtex. A fiber treatment agent was applied, and the fibers were cut to a length of 6 mm.

[0123] Table 1 shows the strength and elongation of matrix fibers 1 to 10, respectively.

[0124] [Table 1]

[0125] The strength and elongation of the fibers were determined in accordance with JIS-L-1015, using a tensile testing machine to measure the load and elongation at which the fiber broke when the gripping distance of the sample was set to 20 mm, and these values ​​were used as the strength and elongation, respectively. Furthermore, the melting point of the crystalline resin after fiberization is the same as the melting point of the thermoplastic resin in the state of being used as matrix fibers (i.e., the melting point after spinning), and can be measured by differential operating calorimetry (DSC). Specifically, based on JIS K 7121 (1987) Method for Measuring Transition Temperatures of Plastics, a differential scanning calorimeter (manufactured by Seiko Instruments Inc.) was used, with a fiber quantity (sample quantity) of 3.0 mg. The fiber was heated from room temperature to 300°C at a heating rate of 10°C / min to melt the fiber, and the melting point was determined from the resulting heat of fusion curve. If multiple peaks are obtained for a single resin, the first melting peak is adopted.

[0126] <Examples 1-1 to 1-7, 2-1 to 2-6, Comparative Examples 1-1 to 1-6, 2-1 to 2-9> [Manufacturing of nonwoven fabrics for composite molded products] Carbon fiber (Teijin, HT C140X (product name)) and aramid fiber (Teijin, Technora (product name)) were prepared as reinforcing fibers. The carbon fiber had a fineness of 0.67 dtex, a fiber diameter of approximately 5 μm, and a fiber length of 6 mm. The aramid fiber had a fineness of 1.7 dtex, a fiber diameter of approximately 12.5 μm, and a fiber length of 6 mm. The reinforcing fibers shown in Tables 2 to 5 were mixed with the matrix fibers shown in Tables 2 to 5 in the mixing ratios shown in Tables 2 to 5, and then processed using a wet papermaking method to produce paper with a basis weight of 200 g / m². 2 A wet-laid nonwoven fabric was obtained. In the production of the wet-laid nonwoven fabric, at least the thermoplastic resin with the lowest Vicat softening temperature among the entangled fibers was softened to partially bond the fibers together. In the production of the wet-laid nonwoven fabric, the fibers were not entangled by mechanical treatment.

[0127] The percentage of ultrafine fibers present on the surface of each nonwoven fabric obtained in the examples and comparative examples was determined and is shown in Tables 2 to 5. Furthermore, the splitting rate of matrix fibers in these nonwoven fabrics was measured and is shown in Tables 2 to 5.

[0128] [Manufacturing of composite molded products] Twelve layers of nonwoven fabric for composite molded products are stacked, resulting in a basis weight of approximately 2400 g / m². 2A laminate (without the nonwoven fabrics being integrated) was prepared, and a heat-pressure treatment was performed on this laminate by applying a pressure of 10 MPa at the temperatures shown in Tables 2 to 5. The high-pressure holding time was 180 seconds. The heat-pressure treatment was performed using a press machine with flat metal plates positioned above and below. The heating temperature was raised over approximately 3 minutes so that the temperature of the mold during the high-pressure holding time reached the temperatures shown in Tables 2 to 5. After the high-pressure holding time, the temperature of the mold was lowered by cooling it with cooling water over approximately 3 minutes so that the temperature of the mold was between 60°C and 50°C. When the heating temperature reached between 60°C and 50°C, the mold was opened and the composite molded body was removed.

[0129] The flexural modulus and flexural strength of the composite molded articles obtained for each example and comparative example were measured by the following method. The measurement results are shown in Tables 2 to 5. <Flexural modulus> In accordance with Method A (bending test method using three-point bending) of JIS K 7074:1998 (Bending test method for carbon fiber reinforced plastics), a sample with a width of 15 mm and a length of 100 mm was prepared from the obtained composite molded body, and the bending modulus was measured at a test speed of 5 mm / min using an Autograph® AG-100kN IS manufactured by Shimadzu Corporation. The sample thickness and the distance between the support points of the Autograph are shown in Tables 2 to 5. In Examples 2-1 to 2-6 and Comparative Examples 2-1 to 2-7, a sample size of 25 mm in width and 80 mm in length was prepared, and the bending modulus was measured at a test speed of 1 mm / min. The sample thickness and the distance between the support points of the Autograph are shown in Tables 2 to 5.

[0130] <Bending strength> In accordance with Method A (bending test method using three-point bending) of JIS K 7074:1998 (Bending test method for carbon fiber reinforced plastics), a sample with a width of 15 mm and a length of 100 mm was prepared from the obtained composite molded body, and the bending strength was measured at a test speed of 5 mm / min using an Autograph® AG-100kN IS manufactured by Shimadzu Corporation. The sample thickness and the distance between the support points of the Autograph are shown in Tables 2 to 5. In Examples 2-1 to 2-6 and Comparative Examples 2-1 to 2-7, a sample size of 25 mm in width and 80 mm in length was prepared, and the bending strength was measured at a test speed of 1 mm / min. The sample thickness and the distance between the support points of the Autograph are shown in Tables 2 to 5. <Bending stress (at specified strain)> In accordance with Method A (bending test method using three-point bending) of JIS K 7074:1998 (Bending test method for carbon fiber reinforced plastics), samples with a width of 15 mm and a length of 100 mm were prepared from the obtained composite molded body, and bending tests were performed at a test speed of 5 mm / min using the Autograph® AG-100kN IS manufactured by Shimadzu Corporation. In addition, the bending stress was calculated in 0.25% increments between bending strains of 0.25% and 2%. In Examples 2-1 to 2-6 and Comparative Examples 2-1 to 2-7, samples with a width of 25 mm and a length of 80 mm were prepared, and bending tests were performed at a test speed of 1 mm / min. In addition, the bending stress was measured in 1.0% increments between bending strains of 2.0% and 15.0%.

[0131] [Table 2]

[0132] [Table 3] [Table 4] [Table 5]

[0133] The composite molded articles of Examples 1-1 to 1-7 all showed higher bending properties compared to Comparative Examples 1-1 to 1-6, which were prepared at the same heating temperature. In a comparison between examples using the same matrix fibers, the one heated at 220°C showed the best bending properties. Furthermore, it was found that even higher bending properties could be obtained by using a compatibilizer when the heating temperature was the same. This is thought to be due to improved affinity between polypropylene and carbon fiber, and between polypropylene and polycarbonate. When comparing the bending stress at various bending strains, Examples 1-1 to 1-7, which used composite fibers in a chrysanthemum composite form, showed higher bending stress than Comparative Examples 1-1 to 1-6 in the entire range of bending strains from 0.25% to 2.0%. This is thought to be because the polycarbonate reinforces the polypropylene, which is the base polymer, and because the composite fibers, which are finely separated by component, are melted, resulting in uniform mixing of each resin.

[0134] Examples 2-1 to 2-6 also showed superior bending properties compared to Comparative Examples 2-1 to 2-6, which were prepared at the same heating temperature. In a comparison between examples using the same matrix fibers, the example heated at 230°C showed the best bending properties. Furthermore, it was found that, at the same heating temperature, examples in which the content of high-impact polystyrene (which exhibits a low Vicat softening temperature) was reduced and polyethylene terephthalate (which exhibits a high Vicat softening temperature) was increased yielded superior bending properties. This is thought to be due to the addition of the rigidity of polyethylene terephthalate to the high-impact polystyrene. Comparing the bending stress at various bending strains for Examples 2-1 to 2-6 and Comparative Examples 2-1 to 2-2, while the curve shape showed a similar trend around 5.0% to 10.0% bending strain, the example using composite fibers with a chrysanthemum composite form showed greater bending stress and thus higher rigidity. On the other hand, Comparative Examples 2-4 to 2-7, in which the matrix was formed with a single fiber, showed a peak in bending stress (bending strength) around 10% bending strain, but their bending strength was smaller than that of the examples, and the peak shape was broad, indicating lower rigidity.

[0135] This embodiment includes the following aspects. (Aspect 1) A composite molded article comprising reinforcing fibers and two or more types of thermoplastic resins as a matrix, The matrix comprises a crystalline thermoplastic resin and an amorphous thermoplastic resin. The crystalline thermoplastic resin has a Vicat softening temperature of 60°C to 260°C, as measured according to the JIS K 7206 B50 method. The amorphous thermoplastic resin has a Vicat softening temperature of 60°C to 300°C, as measured according to the JIS K 7206 B50 method. The matrix comprises three or more sections, each section exposed on the fiber surface, and / or is formed by melting composite fibers in which one section occupies at least 60% of the outer circumference of the fiber's cross-section. Composite molded body. (Aspect 2) A composite molded article according to Embodiment 1, wherein in the matrix, a compatibilizer is added as an additive to at least one of the two or more thermoplastic resins. (Aspect 3) In the combination of the crystalline thermoplastic resin and the amorphous thermoplastic resin, the Vicat softening temperature difference measured according to JIS K 7206 B50 is 1°C or more and 120°C or less. A composite molded article according to embodiment 1 or 2. (Aspect 4) The composite fiber comprises at least one section containing the crystalline thermoplastic resin and at least one section containing the amorphous thermoplastic resin. The section containing the crystalline thermoplastic resin is one of the sections selected from a section containing an olefin resin, a section containing a polyamide resin, and a section containing a polyester resin. The section containing the amorphous thermoplastic resin is one of the sections selected from a section containing a polycarbonate resin and a section containing a styrene resin. A composite molded body according to any of embodiments 1 to 3. (Appendix 5) A composite molded body according to any of embodiments 1 to 4, wherein the reinforcing fibers are carbon fibers and / or aramid fibers. (Aspect 6) A substrate for a composite molded body, comprising reinforcing fibers and composite molded body matrix fibers made of two or more types of thermoplastic resins and including multiple sections, The fiber for the composite molded matrix has three or more sections, and each section is exposed on the fiber surface, or one section occupies at least 60% of the outer circumference of the fiber's cross-section. Of the two or more types of thermoplastic resins mentioned above, at least one is a crystalline thermoplastic resin, and at least one is an amorphous thermoplastic resin. The crystalline thermoplastic resin has a Vicat softening temperature of 60°C to 260°C, as measured according to the JIS K 7206 B50 method. The amorphous thermoplastic resin has a Vicat softening temperature of 60°C to 300°C, as measured according to JIS K 7206 B50 method. Base material for composite molded bodies. (Aspect 7) A composite molded substrate according to embodiment 6, wherein the proportion of ultrafine fibers derived from the composite molded matrix fibers on the surface of the composite molded substrate is 20% or less, and / or the fiber splitting rate of the composite molded matrix fibers in the substrate is 30% or less. [Method for measuring the proportion of ultrafine fibers] (1) The surface of the substrate is observed under magnification using an electron microscope, and the magnified surface is photographed. (2) Count the number of fibers present in the captured image that are for the composite molded matrix and have a length of 200 μm or more, and the number of fibers derived from the composite molded matrix. Of these, fibers that are 150 μm or more in the fiber length direction and have a fiber diameter of less than 1 / 2 are defined as ultrafine fibers. (3) The proportion of ultrafine fibers is determined using the following formula. Percentage of ultrafine fibers expressed (%) = (Number of ultrafine fibers / Number of fibers for composite molded matrix) × 100 [Method for measuring the split fiber ratio] (1) Bundle the substrates so that as little space as possible is created, and cut them to expose the cross-sections so that the fiber cross-sections of the composite mold matrix fibers can be observed. (2) Observe the cross-section by magnifying it 400 to 600 times with an electron microscope, and take a photograph of the magnified cross-section. (3) From the captured images, select the split fibers from among the fibers derived from the composite molded matrix (unsplit fibers and split fibers). Count the number of sections of the split fibers and the number of sections of the unsplit fibers. Unsplit fibers: Fibers having a cross-sectional area that is 1 / 2 or more the cross-sectional area of ​​a completely unsplit fiber. Split fibers: Fibers with a cross-sectional area smaller than half the cross-sectional area of ​​a completely unsplit fiber. (4) The splitting ratio is calculated using the following formula. Splitting rate (%) = [Number of sections of split fibers / (Number of sections of split fibers + Number of sections of unsplit fibers)] × 100 (Pattern 8) A substrate for a composite molded article according to embodiment 6 or 7, wherein a compatibilizer is added as an additive to at least one of the two or more thermoplastic resins mentioned above. (Aspect 9) The composite fiber comprises at least one section containing the crystalline thermoplastic resin and at least one section containing the amorphous thermoplastic resin. The section containing the crystalline thermoplastic resin is one of the sections selected from a section containing an olefin resin, a section containing a polyamide resin, and a section containing a polyester resin. The section containing the amorphous thermoplastic resin is one of the sections selected from a section containing a polycarbonate resin and a section containing a styrene resin. A substrate for a composite molded body according to any of embodiments 6 to 8. (Aspect 10) A substrate for a composite molded article according to embodiment 6 or 7, wherein the reinforcing fibers are carbon fibers and / or aramid fibers. (Aspect 11) A composite molded body substrate according to any one of embodiments 6 to 10, wherein the composite molded body substrate is a nonwoven fabric. (Aspect 12) A substrate for a composite molded body, comprising reinforcing fibers and composite molded body matrix fibers made of two or more types of thermoplastic resins and including multiple sections, The fiber for the composite molded matrix has three or more sections, and each section is exposed on the fiber surface, or one section occupies at least 60% of the outer circumference of the fiber's cross-section. Of the two or more types of thermoplastic resins mentioned above, at least one is a crystalline thermoplastic resin, and at least one is an amorphous thermoplastic resin. The crystalline thermoplastic resin has a Vicat softening temperature of 60°C to 260°C, as measured according to the JIS K 7206 B50 method. The amorphous thermoplastic resin has a Vicat softening temperature of 60°C to 300°C, as measured according to JIS K 7206 B50 method. To prepare a substrate for a composite molded body, and Heating the substrate for the composite molded body. Includes, The heating of the composite molded base material is carried out such that the resin with the lowest Vicat softening temperature among the thermoplastic resins melts and encapsulates the resin component with the highest Vicat softening temperature. This includes further pressurizing when heating the substrate for the composite molded body, The heating and pressurizing are carried out so that the density of the composite molded body becomes 85% or more of the true density. A method for manufacturing a composite molded article. (Aspect 13) The heating of the substrate for the composite molded body is performed as follows: Of the two or more thermoplastic resins mentioned above, the resin with the lowest Vicat softening temperature melts, and When the Vicat softening temperature of the thermoplastic resin with the highest Vicat softening temperature is defined as VST°C, the process is carried out at a temperature between (VST+20)°C and (VST+150)°C. A method for manufacturing a composite molded article according to embodiment 12. (Aspect 14) A method for producing a composite molded article according to embodiment 12 or 13, wherein a compatibilizer is added as an additive to at least one of the two or more thermoplastic resins. (Aspect 15) A composite fiber consisting of two or more types of thermoplastic resins, with three or more sections, Of the two or more types of thermoplastic resins mentioned above, at least one is a crystalline thermoplastic resin, and at least one is an amorphous thermoplastic resin. The crystalline resin has a Vicat softening temperature of 60°C to 260°C, as measured according to the JIS K 7206 B50 method. The amorphous resin has a Vicat softening temperature of 60°C to 300°C, as measured according to the JIS K 7206 B50 method. Fibers for composite molded matrix, wherein each section of the composite fiber is exposed on the fiber surface, or one section occupies at least 60% of the outer circumference of the fiber's cross-section. (Aspect 16) The composite fiber comprises at least one section containing the crystalline thermoplastic resin and at least one section containing the amorphous thermoplastic resin. The section containing the crystalline thermoplastic resin is one of the sections selected from a section containing an olefin resin, a section containing a polyamide resin, and a section containing a polyester resin. The section containing the amorphous thermoplastic resin is one of the sections selected from a section containing a polycarbonate resin and a section containing a styrene resin. Fibers for composite molded body matrix according to embodiment 15. (Aspect 17) Fibers for a composite molded article matrix according to embodiment 15 or 16, wherein a compatibilizer is added as an additive to at least one of the two or more thermoplastic resins mentioned above. [Industrial applicability]

[0136] The composite molded articles of this disclosure have a high density and excellent mechanical properties, as their matrix is ​​formed using specific composite fibers, compared to those made of thermoplastic resin. These composite molded articles are useful as materials for space and aircraft, ships, vehicles (including automobiles and bicycles), sporting goods, office automation equipment, electronic equipment, industrial materials, tanks and containers, general merchandise, and construction materials.

Claims

1. A composite molded article comprising reinforcing fibers and two or more types of thermoplastic resins as a matrix, The matrix comprises a crystalline thermoplastic resin and an amorphous thermoplastic resin. The crystalline thermoplastic resin has a Vicat softening temperature of 60°C to 260°C, as measured according to the JIS K 7206 B50 method. The amorphous thermoplastic resin has a Vicat softening temperature of 60°C to 300°C, as measured according to JIS K 7206 B50 method. The matrix comprises the crystalline thermoplastic resin and the amorphous thermoplastic resin, and is formed by melting composite fibers having three or more sections. The composite fiber is such that each section is exposed on the fiber surface, and / or one section occupies at least 60% of the outer circumference of the fiber's cross-section. Composite molded body.

2. The composite molded article according to claim 1, wherein in the matrix, a compatibilizer is added as an additive to at least one of the two or more thermoplastic resins.

3. In the combination of the crystalline thermoplastic resin and the amorphous thermoplastic resin, the Vicat softening temperature difference measured according to JIS K 7206 B50 is 1°C or more and 120°C or less. The composite molded article according to claim 1.

4. The composite fiber comprises at least one section containing the crystalline thermoplastic resin and at least one section containing the amorphous thermoplastic resin. The section containing the crystalline thermoplastic resin is one of the sections selected from a section containing an olefin resin, a section containing a polyamide resin, and a section containing a polyester resin. The section containing the amorphous thermoplastic resin is one of the sections selected from a section containing a polycarbonate resin and a section containing a styrene resin. The composite molded article according to claim 1.

5. A composite molded article according to any one of claims 1 to 4, wherein the reinforcing fibers are carbon fibers and / or aramid fibers.

6. A substrate for a composite molded body, comprising reinforcing fibers and composite molded body matrix fibers made of two or more types of thermoplastic resins and including multiple sections, The fiber for the composite molded matrix is ​​a composite fiber having three or more sections, i) each section is exposed on the fiber surface, or ii) one section occupies at least 60% of the outer circumference of the fiber's cross-section. Of the two or more types of thermoplastic resins mentioned above, at least one is a crystalline thermoplastic resin, and at least one is an amorphous thermoplastic resin. The crystalline thermoplastic resin has a Vicat softening temperature of 60°C to 260°C, as measured according to the JIS K 7206 B50 method. The amorphous thermoplastic resin has a Vicat softening temperature of 60°C to 300°C, as measured according to JIS K 7206 B50 method. Base material for composite molded bodies.

7. The composite molded substrate according to claim 6, wherein the proportion of ultrafine fibers derived from the composite molded matrix fibers on the surface of the composite molded substrate is 20% or less, and / or the fiber splitting rate of the composite molded matrix fibers in the substrate is 30% or less. [Method for measuring the proportion of ultrafine fibers] (1) Observe the surface of the substrate under magnification using an electron microscope, and take a photograph of the magnified surface. (2) Count the number of fibers present in the captured image that are for the composite molded matrix and have a length of 200 μm or more, and the number of fibers derived from the composite molded matrix. Of these, fibers that are 150 μm or more in the fiber length direction and have a fiber diameter of less than 1 / 2 are defined as ultrafine fibers. (3) The proportion of ultrafine fibers is determined using the following formula. Percentage of ultrafine fibers expressed (%) = (Number of ultrafine fibers / Number of fibers for composite molded matrix) × 100 [Method for measuring the split fiber ratio] (1) Bundle the substrates so that as little space as possible is created, and cut them to expose the cross-sections so that the fiber cross-sections of the composite molded matrix fibers can be observed. (2) Observe the cross-section by magnifying it 400 to 600 times with an electron microscope, and take a photograph of the magnified cross-section. (3) From the captured images, select the split fibers from among the fibers derived from the composite molded matrix fibers (fibers that are not split and fibers that are split). Count the number of sections of split fibers and the number of sections of unsplit fibers. Unsplit fibers: Fibers having a cross-sectional area that is 1 / 2 or more the cross-sectional area of ​​a completely unsplit fiber. Split fibers: Fibers with a cross-sectional area smaller than half the cross-sectional area of ​​a completely unsplit fiber. (4) The splitting ratio is calculated using the following formula. Splitting rate (%) = [Number of sections of split fibers / (Number of sections of split fibers + Number of sections of unsplit fibers)] × 100

8. The substrate for a composite molded article according to claim 6 or 7, wherein a compatibilizer is added as an additive to at least one of the two or more thermoplastic resins.

9. The composite fiber comprises at least one section containing the crystalline thermoplastic resin and at least one section containing the amorphous thermoplastic resin. The section containing the crystalline thermoplastic resin is one of the sections selected from a section containing an olefin resin, a section containing a polyamide resin, and a section containing a polyester resin. The section containing the amorphous thermoplastic resin is one of the sections selected from a section containing a polycarbonate resin and a section containing a styrene resin. A base material for a composite molded article according to claim 6 or 7.

10. The substrate for a composite molded article according to claim 6 or 7, wherein the reinforcing fibers are carbon fibers and / or aramid fibers.

11. The composite molded body substrate according to claim 6 or 7, wherein the composite molded body substrate is a nonwoven fabric.

12. A substrate for a composite molded body, comprising reinforcing fibers and composite molded body matrix fibers made of two or more types of thermoplastic resins and including multiple sections, The fiber for the composite molded matrix is ​​a composite fiber having three or more sections, i) each section is exposed on the fiber surface, or ii) one section occupies at least 60% of the outer circumference of the fiber's cross-section. Of the two or more types of thermoplastic resins mentioned above, at least one is a crystalline thermoplastic resin, and at least one is an amorphous thermoplastic resin. The crystalline thermoplastic resin has a Vicat softening temperature of 60°C to 260°C, as measured according to the JIS K 7206 B50 method. The amorphous thermoplastic resin has a Vicat softening temperature of 60°C to 300°C, as measured according to JIS K 7206 B50 method. To prepare a substrate for a composite molded body, and Heating the substrate for the composite molded body. Includes, The heating of the composite molded base material is carried out such that the resin with the lowest Vicat softening temperature among the thermoplastic resins melts and encapsulates the resin component with the highest Vicat softening temperature. This includes further pressurizing when heating the substrate for the composite molded body, The heating and pressurizing are carried out so that the density of the composite molded body becomes 85% or more of its true density. A method for manufacturing a composite molded article.

13. The heating of the substrate for the composite molded body is performed as follows: Of the two or more thermoplastic resins mentioned above, the resin with the lowest Vicat softening temperature melts, and When the Vicat softening temperature of the thermoplastic resin with the highest Vicat softening temperature is defined as VST°C, the process is carried out at a temperature between (VST + 20)°C and (VST + 150)°C. A method for manufacturing a composite molded article according to claim 12.

14. A method for producing a composite molded article according to claim 12 or 13, wherein a compatibilizer is added as an additive to at least one of the two or more thermoplastic resins.

15. A composite fiber consisting of two or more types of thermoplastic resins and having three or more sections, Of the two or more types of thermoplastic resins mentioned above, at least one is a crystalline thermoplastic resin, and at least one is an amorphous thermoplastic resin. The crystalline resin has a Vicat softening temperature of 60°C to 260°C, as measured according to the JIS K 7206 B50 method. The amorphous resin has a Vicat softening temperature of 60°C to 300°C, as measured according to JIS K 7206 B50 method. Fibers for composite molded matrix, wherein each section of the composite fiber is exposed on the fiber surface, or one section occupies at least 60% of the outer circumference of the fiber's cross-section.

16. The composite fiber comprises at least one section containing the crystalline thermoplastic resin and at least one section containing the amorphous thermoplastic resin. The section containing the crystalline thermoplastic resin is one of the sections selected from a section containing an olefin resin, a section containing a polyamide resin, and a section containing a polyester resin. The section containing the amorphous thermoplastic resin is one of the sections selected from a section containing a polycarbonate resin and a section containing a styrene resin. Fibers for composite molded article matrix according to claim 15.

17. Fibers for composite molded article matrix according to claim 15 or 16, wherein a compatibilizer is added as an additive to at least one of the two or more thermoplastic resins.

Images