Polycarbonate fiber, fiber structure and resin composite

Abstract

The present invention provides a polycarbonate fiber and a fiber structure and a resin composite having a specific orientation degree and / or birefringence value. In the polycarbonate fiber, the orientation degree ft represented by the following formula may be less than 0.70, and the birefringence value may be less than 0.04. ft = 1-(1.0 / C) 2 C: Measured sound velocity value (km / sec) The number average molecular weight (Mn) of the polycarbonate resin constituting the polycarbonate fiber may be 12,000 to 40,000, and / or the weight average molecular weight (Mw) may be 25,000 to 80,000.

Description

Technical Field

[0001] The present invention relates to polycarbonate fibers having specific orientation and / or birefringence value and fiber structures using the fibers, and also to resin composites using the fibers melted and used as a matrix. Background Art

[0002] Polycarbonate resins have high impact resistance and can be used as panels and plates. They can also be used for lamp covers of automobiles and the like, helmets of motorcycles, and the like by injection molding or the like.

[0003] On the other hand, it is proposed to use a fiberized polycarbonate resin as a molding matrix. For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 4-146210) proposes a polycarbonate multifilament yarn for a molding matrix resin, which is a multifilament yarn obtained by melt spinning or further stretching polycarbonate, wherein the birefringence of the multifilament yarn is greater than or equal to 0.01 and less than or equal to 0.03, and the elongation at break is greater than or equal to 40% and less than or equal to 100%.

[0004] In addition, Patent Document 2 (International Publication No. 2014 / 021084) proposes: polycarbonate fibers are obtained by melt spinning a polycarbonate resin, the polycarbonate fibers, carbon fibers and binder fibers are mixed to form a dry nonwoven fabric, and the dry nonwoven fabric is further laminated and the polycarbonate fibers are melted by heat pressing to form a resin composite.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 4-146210

[0008] Patent Document 2: International Publication No. 2014 / 021084 Summary of the invention

[0009] Problems to be solved by the invention

[0010] However, the polycarbonate fibers obtained in Patent Document 1 cannot be oriented within a given range because a high molecular weight polycarbonate resin is spun at a low temperature. Furthermore, since the melt molding temperature of the molded product using the polycarbonate fibers is only 250° C., the obtained molded product does not have excellent heat resistance at high temperatures.

[0011] In addition, in the melt spinning performed in Patent Document 2, the orientation degree of the polycarbonate fibers may not be controlled within a given range due to the low spinning temperature. As a result, when a fabric consisting of polycarbonate fibers alone is temporarily melted by heat treatment to form a resin composite, when the polycarbonate fibers are melted, the orientation degree of the fibers themselves is greatly reduced and the fibers shrink, resulting in problems such as resin unevenness, warping, and deformation of the molded product.

[0012] Methods for solving problems

[0013] From the viewpoint of solving the above-mentioned problems, the present inventors conducted research and found that polycarbonate fibers useful as a base material for a molded body must not only ensure fluidity during molding, but also ensure the physical properties of the molded body. The spinning temperature used in the existing spinning process was further increased to improve the mixability of the resin. As a result, the orientation and / or birefringence of the polycarbonate fibers obtained by ejection can be controlled within a given range.

[0014] Furthermore, surprisingly, polycarbonate fibers having such orientation and / or birefringence can reduce the shrinkage of the fibers during melt molding even when they are melted at high temperatures and used as a base material for a molded body, thereby suppressing not only resin unevenness of the molded body but also warping, deformation, etc., thereby improving moldability and completing the present invention.

[0015] That is, the present invention can be constituted in the following aspects.

[0016] [Method 1]

[0017] A polycarbonate fiber having an orientation degree ft represented by the following formula of less than 0.70 (preferably 0.68 or less, more preferably 0.65 or less, further preferably 0.62 or less, particularly preferably 0.61 or less).

[0018] ft=1-(1.0 / C) 2

[0019] C: Measured sound speed (km / s)

[0020] [Method 2]

[0021] A polycarbonate fiber having an orientation degree ft represented by the following formula of less than 0.70 (preferably less than 0.68, more preferably less than 0.65, further preferably less than 0.62, particularly preferably less than 0.61), and a birefringence value of less than 0.040 (preferably less than 0.035, more preferably less than 0.030, further preferably less than 0.025, particularly preferably less than 0.010).

[0022] ft=1-(1.0 / C) 2

[0023] C: Measured sound speed (km / s)

[0024] [Method 3]

[0025] The polycarbonate fiber according to method 1 or 2, wherein the number average molecular weight (Mn) of the polycarbonate resin constituting the polycarbonate fiber is 12000 to 40000 (preferably 15500 to 25000), and / or the weight average molecular weight (Mw) is 25000 to 80000 (preferably 35000 to 65000, more preferably 45000 to 55000).

[0026] [Method 4]

[0027] A polycarbonate fiber having a birefringence value of 0.040 or less (preferably 0.035 or less, more preferably 0.030 or less, further preferably 0.025 or less, and particularly preferably less than 0.010), and a polycarbonate resin constituting the polycarbonate fiber having a number average molecular weight (Mn) of 12,000 to 40,000 (preferably 15,500 to 25,000), and / or a weight average molecular weight (Mw) of 25,000 to 80,000 (preferably 35,000 to 65,000, more preferably 45,000 to 55,000).

[0028] [Method 5]

[0029] The polycarbonate-based fiber according to any one of aspects 1 to 4 has a molecular weight distribution (Mw / Mn) of 2.0 to 4.0 (preferably 2.2 to 4.0, more preferably 2.5 to 3.5, further preferably 2.7 to 3.3, particularly preferably 2.7 to 3.1).

[0030] [Method 6]

[0031] The polycarbonate-based fiber according to any one of aspects 1 to 5, wherein the elastic modulus of the fiber is 30 cN / dtex or less (preferably 27 cN / dtex or less, more preferably 25 cN / dtex or less).

[0032] [Method 7]

[0033] The polycarbonate-based fiber according to any one of aspects 1 to 6, wherein the coefficient of variation of the fiber diameter is 15% or less (preferably 10% or less, more preferably 5% or less).

[0034] [Method 8]

[0035] The polycarbonate-based fiber according to any one of aspects 1 to 7, wherein the single fiber fineness is 10 dtex or less (preferably 4.5 dtex or less, more preferably 3.5 dtex or less).

[0036] [Method 9]

[0037] The polycarbonate-based fiber according to any one of aspects 1 to 8, wherein the fiber has a breaking elongation of 20% or more (preferably 40% or more, more preferably 80% or more, and even more preferably 103% or more).

[0038] [Method 10]

[0039] The polycarbonate fiber according to any one of aspects 1 to 9, wherein the ratio (mol %) of the bisphenol A skeleton to the whole monomer unit in the polycarbonate resin is 65% or more (preferably 75% or more).

[0040] [Method 11]

[0041] The polycarbonate-based fiber according to any one of aspects 1 to 10, comprising a phosphorus-based flame retardant.

[0042] [Method 12]

[0043] The polycarbonate-based fiber according to aspect 11 contains at least one phosphorus-based flame retardant selected from the group consisting of a phosphate-based flame retardant, a phosphate flame retardant, and a phosphazene-based flame retardant.

[0044] [Method 13]

[0045] A fiber structure comprising the polycarbonate fiber according to any one of the first to twelfth aspects.

[0046] [Method 14]

[0047] The fiber structure according to embodiment 13 is a mixed filament, a woven fabric, or a nonwoven fabric.

[0048] [Method 15]

[0049] A method for producing polycarbonate fibers, the method comprising: a melt-kneading step of melt-kneading a polycarbonate resin at a high temperature of 305°C or above (preferably 310°C or above, and more preferably 315°C or above) to obtain a molten polymer; a spraying step of spraying the molten polymer in a given amount from a spinning nozzle; and a winding step of winding the sprayed filaments at a given pulling speed.

[0050] Effects of the Invention

[0051] The polycarbonate fibers of the present invention can reduce shrinkage of the fibers during melt molding at high temperatures by controlling the degree of fiber orientation, thereby suppressing resin unevenness, warping, deformation, etc. of the molded product, thereby improving moldability. DETAILED DESCRIPTION

[0052] (Polycarbonate resin)

[0053] The present invention is described in detail below. First, the polycarbonate resin constituting the polycarbonate fiber of the present invention is described. The polycarbonate resin used in the present invention is a polymer containing a repeating unit represented by the following formula, and is not particularly limited as long as it has melt moldability.

[0054] [Chemical formula 1]

[0055]

[0056] In the formula, X can be a direct bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, an oxygen atom, a sulfur atom, -CO-, -SO-, or -SO2-.

[0057] The polycarbonate resin preferably has a bisphenol A skeleton in which X is a methylene group. For example, in the monomer unit in the polycarbonate resin, the ratio (mol %) of the bisphenol A skeleton relative to the whole can be 65% or more, and can preferably be 75% or more. In addition, the polycarbonate resin can have a branched chain, but its degree of branching is preferably less than 0.1 mol%. Here, the degree of branching is expressed as the ratio (mol %) of the total number of moles of the branched structural unit relative to 1 mol of repeating units of the polycarbonate. It should be noted that the branched structural unit refers to a repeating unit in which an ester bond (-COO-) is bonded to the aromatic ring in the above-mentioned repeating unit as a substituent.

[0058] The weight average molecular weight (Mw) of the polycarbonate resin used in the present invention may be about 25,000 to 80,000, preferably about 35,000 to 65,000, and more preferably about 45,000 to 55,000. When the weight average molecular weight is lower than the above range, the dimensional stability of the obtained fiber and the mechanical properties of the composite material when the molded body is made are sometimes reduced. In addition, when the weight average molecular weight exceeds the above range, the melt spinnability during fiberization and the impregnation property of the composite material are sometimes reduced.

[0059] The number average molecular weight (Mn) of the polycarbonate resin may be about 12000 to 40000, and preferably about 15500 to 25000. When the number average molecular weight is within the above range, the dimensional stability of the obtained fiber and the mechanical properties of the composite material when formed into a molded body are good.

[0060] For the polycarbonate resin used in the present invention, from the viewpoint of fluidity during melt spinning and the physical properties of polycarbonate fibers and their molded products, the molecular weight distribution (Mw / Mn), which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), can be 2.0 to 4.0 (for example, 2.2 to 4.0), preferably 2.5 to 3.5, more preferably 2.7 to 3.3, and particularly preferably 2.7 to 3.1.

[0061] The number average molecular weight (Mn), the weight average molecular weight (Mw), and the molecular weight distribution can be calculated in terms of polystyrene using, for example, gel permeation chromatography (GPC), which is one type of size exclusion chromatography (SEC).

[0062] The melt viscosity of polycarbonate resin is, for example, 320°C and a shear rate of 1000 sec. -1 The melt viscosity may be 600 to 4000 poise, more preferably 800 to 3000 poise.

[0063] The melt flow rate (MFR) of the polycarbonate resin measured in accordance with ISO1183 may be, for example, 8 to 20 g / 10 minutes, and more preferably 11 to 18 g / 10 minutes.

[0064] The polycarbonate resin used in the present invention may contain a flame retardant, a heat stabilizer, an antioxidant, a radical inhibitor, a matting agent, an ultraviolet absorber, a dye / pigment, and other polymers within a range not impairing the effects of the present invention.

[0065] In particular, when the polycarbonate fiber is used for flame retardant purposes, the polycarbonate resin preferably contains a flame retardant. The flame retardant can be appropriately selected as long as melt spinning is possible, and a phosphorus flame retardant is preferably used from the viewpoint of being able to suppress aggregation of the flame retardant.

[0066] More specifically, phosphate flame retardants such as triphenyl phosphate, aromatic condensed phosphate, tricresol phosphate, tri(xylene) phosphate, toluene diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, aromatic phosphate, tri(dichloropropyl) phosphate, tri(β-chloropropyl) phosphate, halogenated phosphate, polyphosphates, phosphazene flame retardants, red phosphorus flame retardants, etc. can be listed. These flame retardants can also include copolymers. Among them, as phosphorus flame retardants, preferred phosphate flame retardants, phosphate flame retardants, and phosphazene flame retardants are.

[0067] The phosphorus-based flame retardant may be contained in the polycarbonate-based fibers in an amount of, for example, about 20 to 20,000 ppm, preferably about 40 to 18,000 ppm, calculated as phosphorus.

[0068] (Polycarbonate fiber)

[0069] The polycarbonate fibers of the present invention have a specific degree of orientation, and thus can reduce shrinkage under high temperature conditions.

[0070] The orientation degree of the entire molecule can be determined by measuring the sonic velocity and using the following formula to determine the orientation degree ft.

[0071] ft=1-(1.0 / C) 2

[0072] C: Measured sound speed (km / s)

[0073] It should be noted that 1.0 in the formula is the sonic velocity value of the non-oriented PC polymer.

[0074] The orientation degree of the polycarbonate fiber may be less than 0.70, and may preferably be 0.68 or less, more preferably 0.65 or less, further preferably 0.62 or less, and particularly preferably 0.61 or less. The lower limit of the orientation degree is not particularly limited, and may be 0.1 or more.

[0075] In addition, since the polycarbonate fiber of the present invention is manufactured by a specific manufacturing method, the birefringence value can be controlled to a specific range, and the birefringence value can be 0.040 or less, preferably 0.035 or less, more preferably 0.030 or less, further preferably 0.025 or less, and particularly preferably less than 0.010. There is no particular restriction on the lower limit of the birefringence value, and it can be 0.0001 or more. It should be noted that the birefringence value is a value measured by the method described in the examples described later.

[0076] In addition, the polycarbonate fiber of the present invention preferably has excellent flame retardancy. For example, the limiting oxygen index value (LOI value) of the fiber may be 22.0 or more, preferably 23.0 or more, more preferably 24.0 or more, further preferably 26.0 or more, and particularly preferably 28.0 or more. In addition, the higher the limiting oxygen index value, the more preferred, but in most cases it is 40 or less. In addition, the limiting oxygen index value (LOI value) of the resin (which may contain a flame retardant) constituting the polycarbonate fiber of the present invention may be within the above range. It should be noted that the limiting oxygen index value of the fiber referred to here is a value measured by the method described in the examples described later.

[0077] In addition, the single fiber fineness of the polycarbonate fiber of the present invention can be set according to the application, and the single fiber fineness can be, for example, 10 dtex or less. When used as a molding base material, from the viewpoint of the miscibility with the reinforcing fiber, the single fiber fineness of the polycarbonate fiber can be preferably 4.5 dtex or less, and more preferably 3.5 dtex or less. The lower limit of the single fiber fineness is not particularly limited, and can be, for example, about 0.3 dtex.

[0078] The polycarbonate fiber of the present invention is manufactured by a specific manufacturing method, so the coefficient of variation of the fiber diameter can be reduced. For example, the coefficient of variation of the fiber diameter can be 15% or less, preferably 10% or less, and more preferably 5% or less. The coefficient of variation of the fiber diameter is a value measured by the method described in the embodiments described below. In addition, the smaller the coefficient of variation, the more the melting uniformity when the fiber is melt-molded can be improved, so it is preferred.

[0079] In addition, the fiber strength (breaking strength) of the polycarbonate fiber of the present invention at room temperature may be 0.8 cN / dtex or more, and may preferably be 1.0 cN / dtex or more. The upper limit of the fiber strength is not particularly limited, and may be, for example, about 4.0 cN / dtex. It should be noted that the fiber strength is a value measured by the method described in the examples described later.

[0080] In addition, the elongation at break of the polycarbonate fiber of the present invention at room temperature (25° C.) may be 20% or more, preferably 40% or more, more preferably 80% or more, and even more preferably 103% or more. The upper limit of the elongation at break is not particularly limited, and may be, for example, about 200%. It should be noted that the elongation at break is a value measured by the method described in the examples described later.

[0081] In addition, the elastic modulus of the polycarbonate fiber of the present invention at room temperature may be 30 cN / dtex or less, preferably 27 cN / dtex or less, and more preferably 25 cN / dtex or less. The lower limit of the elastic modulus is not particularly limited, and may be, for example, about 5 cN / dtex. It should be noted that the elastic modulus is a value measured by the method described in the embodiments described later.

[0082] From the viewpoint of heat resistance of the molded article, the glass transition temperature (Tg) of the polycarbonate fiber of the present invention may be 135° C. or higher, preferably 140° C. or higher, and more preferably 145° C. or higher. The glass transition temperature is a value measured by the method described in the Examples below.

[0083] In addition, from the viewpoint of suppressing the occurrence of resin unevenness, warping, deformation, etc. of the molded body, the polycarbonate fibers of the present invention can reduce the dry heat shrinkage at high temperatures (for example, about 110 to 170°C). For example, the dry heat shrinkage under no tension at 140°C can be 8% or less, preferably 5% or less, more preferably 3.5% or less, further preferably 2% or less, and particularly preferably 1.5% or less. The lower limit of the dry heat shrinkage is not particularly limited, and is preferably 0%, for example, it can be about 0.5%. It should be noted that the dry heat shrinkage is a value measured by the method described in the examples described later.

[0084] (Method for producing polycarbonate fibers)

[0085] Specifically, the polycarbonate fibers of the present invention can achieve a specific degree of orientation and / or birefringence value by melt spinning at a high temperature. The method for producing polycarbonate fibers includes: a melt kneading step of melt kneading a polycarbonate resin at a high temperature (e.g., above 305° C.) to obtain a molten polymer; a spraying step of spraying the molten polymer from a spinning nozzle in a given amount; and a winding step of winding the sprayed filaments (or molten raw yarns) at a given drawing speed (or spinning speed).

[0086] More specifically, when the polycarbonate fibers of the present invention are melt-spinned, a known melt-spinning device can be used. For example, pellets of polycarbonate resin are melt-kneaded using a melt extruder, and the molten polymer is introduced into a spinning cylinder. Then, the molten polymer is measured by a gear pump, a given amount is ejected from a spinning nozzle, and the obtained filaments are wound up, thereby making it possible to manufacture the polycarbonate fibers of the present invention. It should be noted that the filaments wound up after melt spinning have a desired fineness at the winding stage, and therefore can be used directly without being stretched.

[0087] When the heating temperature during melt kneading is high, the melt viscosity of the polycarbonate resin decreases, the spinning tension decreases, and thus the orientation degree and / or birefringence value of the fiber can be reduced. The heating temperature can be appropriately set according to the type of polycarbonate resin. From the viewpoint of controlling the orientation degree and / or birefringence value of the polycarbonate fiber, the heating temperature can be preferably 305°C or higher, more preferably 310°C or higher, and further preferably 315°C or higher. The upper limit of the heating temperature varies depending on the decomposition temperature of the resin, and can be, for example, about 350°C.

[0088] The size of the spinning hole (single hole) of the spinning nozzle can be, for example, 0.02 to 1 mm. 2 About 0.03 to 0.5 mm is preferred 2 About 0.05 to 0.15 mm is more preferred 2It should be noted that the shape of the spinning hole can be appropriately selected according to the desired fiber cross-sectional shape. In addition, in order to reduce fiber orientation, the nozzle may have a tapered hole. In particular, the tapered hole may increase in diameter along the ejection direction at an angle of 3 to 25 degrees relative to the central axis of the ejection hole of the spinning nozzle.

[0089] The amount of the fiber ejected from the spinning nozzle can be appropriately set according to the number of holes and the hole diameter of the nozzle, and can be, for example, about 10 to 300 g / min, preferably about 20 to 280 g / min.

[0090] The ejection speed from the spinning nozzle can be appropriately set according to the viscosity of the molten polymer at the spinning temperature, the nozzle aperture, and the ejection amount. By making it relatively low, the shear stress applied to the molten polymer in the nozzle can be reduced. For example, the ejection speed can be in the range of 2.54 to 42.4 m / min, preferably 4.24 to 33.9 m / min, and more preferably 4.24 to 25.4 m / min.

[0091] The pulling speed (spinning speed) at this time can be appropriately set according to the nozzle hole diameter and the ejection amount. From the viewpoint of suppressing the occurrence of molecular orientation on the spinning line, it is preferably pulled in the range of 500 to 4000 m / min, more preferably 600 to 3000 m / min, further preferably 800 to 2500 m / min, and particularly preferably 800 to 2000 m / min.

[0092] From the viewpoint of adjusting the orientation of the fiber, the draft ratio (ratio of the ejection speed to the take-up speed) during spinning may be, for example, in the range of 2 to 300, preferably 5 to 200, more preferably 20 to 150, and even more preferably 30 to 100.

[0093] For the polycarbonate fibers of the present invention, from the viewpoint of reducing dry heat shrinkage, the filaments ejected from the spinning nozzle are preferably kept in their original state without being stretched, or stretched with the stretching ratio set as low as possible (for example, a stretching ratio of about 1.0 to 1.3).

[0094] The polycarbonate-based fibers of the present invention can be used in any fiber form, such as staple fibers, chopped fibers, filament yarns, spun yarns, threads, and ropes.

[0095] In addition, the polycarbonate fiber may be a non-composite fiber or a composite fiber. There is no particular limitation on the cross-sectional shape of the fiber, and the cross-sectional shape may be circular, hollow, star-shaped or other special-shaped.

[0096] In addition, the polycarbonate fibers of the present invention can also be used as fabrics. As fabrics, the shape is not particularly limited as long as the polycarbonate fibers of the present invention are used, and the shape of the fabrics includes various fabrics such as nonwoven fabrics (including paper), woven fabrics, and knitted fabrics. Such fabrics can be produced using polycarbonate fibers by known or conventional methods.

[0097] In the case of using fine-denier fibers, the polycarbonate fabric of the present invention is preferably melted to form a resin composite because uniformity can be improved. In the case of a nonwoven fabric, it is also preferably formed into a nonwoven fabric with excellent blending properties.

[0098] The polycarbonate fiber may be combined with other fibers as long as the effect of the present invention is not impaired. The polycarbonate fabric may contain the polycarbonate fiber obtained according to the present invention as, for example, a main fiber, and the proportion thereof may be 50% by mass or more, preferably 80% by mass or more, and particularly 90% by mass or more relative to the whole. By making such a fabric (particularly paper, nonwoven fabric), a fabric that fully utilizes the characteristics of the polycarbonate fiber can be obtained.

[0099] Polycarbonate fibers and polycarbonate fabrics can be used very effectively in various forms for a wide variety of applications, including industrial materials, agricultural materials, civil engineering materials, electrical and electronic materials, optical materials, and aircraft, automobile, and ship fields.

[0100] (Method for producing resin composite)

[0101] The method for producing a resin composite of the present invention comprises at least: a step of preparing the polycarbonate fiber or fabric; and a heat-molding step of heating the polycarbonate fiber or fabric at a temperature not lower than the glass transition temperature.

[0102] The heat molding method is not particularly limited as long as the polycarbonate fibers or fabrics are melted and integrated, and a common resin composite molding method can be appropriately used.

[0103] When the resin composite is heated and molded, it can be molded under pressure. The pressure is not particularly limited, but is usually 0.05 N / mm 2 Above (e.g. 0.05~15N / mm 2 The time for heat molding is not particularly limited, but if exposed to high temperature for a long time, the polymer may deteriorate, so it is usually preferably within 30 minutes.

[0104] It should be noted that the shape of the resin composite is not particularly limited and can be appropriately set according to the purpose. It is also possible to stack a plurality of fabrics of different specifications or to place the fabrics of different specifications in a mold of a certain size for heat molding. Depending on the situation, it is also possible to mold together with other reinforcing fiber fabrics and resin composites. In addition, the resin composite obtained by heat molding once can also be heat molded again according to the purpose.

[0105] The density of the resin composite of the present invention is preferably 2.00 g / cm 3 Below. Density greater than 2.00g / cm 3 When the weight is less than 1.95 g / cm, it is not conducive to lightweight resin composites, and the use is sometimes limited. Preferably, it is 1.95 g / cm 3 Below, more preferably 1.90 g / cm 3 The lower limit of density can be appropriately determined according to the choice of material, for example, it can be 0.5 g / cm 3 about.

[0106] In addition, the thickness of the resin composite of the present invention is preferably 0.3 mm or more (preferably 0.5 mm or more). When the thickness is too thin, the strength of the obtained resin composite is reduced or the production cost is increased. It is more preferably 0.7 mm or more, and further preferably 1 mm or more. In addition, the upper limit of the thickness can be appropriately set according to the thickness required for the resin composite, for example, it can be about 10 mm.

[0107] The resin composite of the present invention not only has excellent mechanical properties and heat resistance, but also can be manufactured inexpensively without special processes. Therefore, it can be suitably used as frames for computers, displays, OA equipment, mobile phones, portable information terminals, digital cameras, optical equipment, audio players, air conditioners, lighting equipment, toys, electrical appliances, electronic equipment parts, other home appliances, etc.; civil engineering / building material parts such as interior components, exterior components, pillars, panels, and reinforcing materials; various parts of vehicles (automobiles, bicycles, ships, airplanes, etc.), various frames, various hinges, various brackets, various axles, various wheel bearings, various beams, various columns, various beams, Various supports, various guide rails; dashboards, seat frames, door trims, pillar trims, handles, various modules and other interior parts for vehicles; chassis, trays, outer panels, or body parts, bumpers, moldings, bottom covers, engine hoods, fairings, spoilers, front shutters, aviation parts and other exterior parts for vehicles; engine parts, CNG boxes, gasoline tanks, fuel pumps, air intakes, intake manifolds, carburetor bodies, carburetor baffles, various piping, various valves and other parts of fuel systems, exhaust systems or intake systems for vehicles; landing gear pods, winglets, spoilers, edges, rudders, elevators, fairings, ribs and other drone / aircraft parts, etc.

[0108] The present invention is described in more detail below by way of examples, but the present invention is not limited to these examples. It should be noted that in the following examples, various physical properties represent values ​​measured by the following methods.

[0109] [Molecular weight distribution Mw / Mn]

[0110] The molecular weight distribution of the sample was measured using a gel permeation chromatograph (GPC) and GPC101 (polystyrene conversion) manufactured by SHODEX. Tetrahydrofuran was used as a solvent, and the sample was dissolved in a manner of 0.2 mass %, and then filtered and provided for measurement. The molecular weight distribution (Mw / Mn) was obtained based on the ratio of the obtained weight average molecular weight (Mw) to the number average molecular weight (Mn).

[0111] [Orientation degree]

[0112] The orientation degree of the whole molecule is obtained from the sound velocity. The sound velocity is measured using DDV-5-B manufactured by Rheovibron. A fiber bundle with a fiber length of 50 cm is fixed on the device, a load of 0.1 g / dtex is applied, and the propagation time of the sound wave at each point where the distance from the sound source to the detector is 50, 40, 30, 20, and 10 cm is measured. The sound velocity (n=5) is obtained based on the relationship between the distance and the propagation time.

[0113] The sonic velocity, which is an index of the orientation degree of the entire molecule, was measured, and the orientation degree ft was calculated according to the following formula.

[0114] ft=1-(1.0 / C) 2

[0115] C: Measured speed of sound (km / s)

[0116] [Birefringence value]

[0117] The birefringence value was calculated by the following formula from the retardation measured under a light source of λ=546.1 nm (e-line) using a polarizing microscope "BX53" manufactured by Olympus equipped with a Berek compensator.

[0118] Δn=R / d

[0119] Δn: birefringence value, R: retardation (nm), d: fiber thickness (nm)

[0120] [Fiber strength and elastic modulus (cN / dtex)]

[0121] According to the JIS L1013 test method, the pre-humidified yarn was measured at room temperature (25°C), with a test length of 20 cm, an initial load of 0.18 cN / dtex, and a tensile speed of 10 cm / min, and the average value of n = 10 was used. In addition, the fiber fineness (dtex) was determined by the mass method.

[0122] [Dry heat shrinkage under no tension (%)]

[0123] Fibers cut into 10 cm pieces or cloth made of the fibers cut into 10 cm square pieces were kept in an air thermostatic chamber maintained at 140°C for 30 minutes without fixing the ends, and then the fiber length or cloth length (X cm) was calculated using the following formula.

[0124] Dry heat shrinkage (%) = {(10-X) / 10}×100

[0125] [Glass transition temperature Tg (℃)]

[0126] The glass transition temperature of the fiber was measured by using "TA3000-DSC" manufactured by Mettler Co., Ltd. in a nitrogen atmosphere at a heating rate of 10°C / min to 350°C. The glass transition temperature was determined as an inflection point of the DSC spectrum.

[0127] [Limiting oxygen index (LOI) value of fiber]

[0128] According to the JIS K7201 test method, a test sample with a test length of 18 cm is made by weaving three bundles of fibers. When the upper end of the sample is ignited, the minimum oxygen concentration required for the sample to continue burning for more than 3 minutes or the burning length after ignition to continue burning for more than 5 cm is measured, and the average value of n=3 is used.

[0129] [Evaluation of Spinning Properties]

[0130] In the step of spinning and fiberizing 50 kg of the resin, the number of fiber breakages was evaluated as follows.

[0131] ○: 3 times or less / 50kg, △: 4 to 7 times / 50kg, ×: 8 times or more / 50kg

[0132] [Example 1]

[0133] As a polycarbonate resin, a resin with Mw: 52300, Mn: 17300, Mw / Mn=3.0, and a LOI value of 34 containing bisphenol A-bis(diphenyl phosphate) as a flame retardant in an amount of 40 ppm in terms of phosphorus was used. The resin was melt-extruded by a twin-screw extruder, and ejected through a 0.2 mm Φ×100 hole round hole nozzle at a spinning temperature of 320°C. The ratio of the ejection speed to the winding speed (draft ratio) was adjusted to 143, and the winding was performed at a winding speed of 1500 m / min. The single-filament fineness of the obtained raw yarn was 2.2 dtex, and Tg was 145°C. The obtained fiber was evaluated, and the results are shown in Table 1.

[0134] [Example 2]

[0135] As a polycarbonate resin, a resin with Mw: 52300, Mn: 17300, Mw / Mn=3.0, and a LOI value of 34 containing bisphenol A-bis(diphenyl phosphate) as a flame retardant in an amount of 40 ppm calculated as phosphorus was used. The resin was melt-extruded by a twin-screw extruder, and ejected through a 0.2 mm Φ×100 hole round hole nozzle at a spinning temperature of 320°C. The ratio of the ejection speed to the winding speed (draft ratio) was adjusted to 95, and the winding was performed at a winding speed of 1000 m / min. The single-filament fineness of the obtained raw yarn was 3.3 dtex, and Tg was 145°C. The obtained fiber was evaluated, and the results are shown in Table 1.

[0136] [Example 3]

[0137] As a polycarbonate resin, a resin with Mw: 52300, Mn: 17300, Mw / Mn=3.0, and a LOI value of 34 containing bisphenol A-bis(diphenyl phosphate) as a flame retardant in an amount of 40 ppm calculated as phosphorus was used. The resin was melt-extruded by a twin-screw extruder, and ejected through a 0.2 mm Φ×100 hole round hole nozzle at a spinning temperature of 320°C. The ratio of the ejection speed to the winding speed (draft ratio) was adjusted to 63, and the winding was carried out at a winding speed of 666 m / min. The single-filament fineness of the obtained raw yarn was 4.9 dtex, and Tg was 145°C. The obtained fiber was evaluated, and the results are shown in Table 1.

[0138] [Example 4]

[0139] As a polycarbonate resin, a resin with Mw: 49800, Mn: 17000, Mw / Mn=2.9, and LOI value of 26 was used. The resin was melt-extruded by a twin-screw extruder and ejected through a 0.2mmΦ×100 hole round hole nozzle at a spinning temperature of 320°C. The ratio of the ejection speed to the winding speed (draft ratio) was adjusted to 63, and the winding was carried out at a winding speed of 666m / min. The single-filament fineness of the obtained raw yarn was 4.9dtex, and Tg was 150°C. The obtained fiber was evaluated, and the results are shown in Table 1.

[0140] [Comparative Example 1]

[0141] As a polycarbonate resin, a resin with Mw: 135000, Mn: 56000, Mw / Mn=2.4, and LOI value of 26 was used. The resin was melt-extruded by a twin-screw extruder and ejected through a 0.2mmΦ×100 hole round hole nozzle at a spinning temperature of 290°C. The ratio of the ejection speed to the winding speed (draft ratio) was adjusted to 63, and the winding was carried out at a winding speed of 666m / min. The single-filament fineness of the obtained raw yarn was 4.9dtex. The obtained fibers were evaluated, and the results are shown in Table 1.

[0142] [Comparative Example 2]

[0143] As a polycarbonate resin, a resin with Mw: 49800, Mn: 17000, Mw / Mn=2.9, and LOI value of 26 was used. The resin was melt-extruded by a twin-screw extruder and ejected through a 0.2mmΦ×100 hole round hole nozzle at a spinning temperature of 290°C. The ratio of the ejection speed to the winding speed (draft ratio) was adjusted to 63, and the winding was carried out at a winding speed of 666m / min. The single-filament fineness of the obtained raw yarn was 4.9dtex, and Tg was 150°C. The obtained fiber was evaluated, and the results are shown in Table 1.

[0144] [Comparative Example 3]

[0145] As a polycarbonate resin, a resin with Mw: 90000, Mn: 28000, Mw / Mn=3.2, and a LOI value of 37 containing bisphenol A-bis(diphenyl phosphate) as a flame retardant in an amount of 80 ppm calculated as phosphorus was used. The resin was melt-extruded by a twin-screw extruder, and ejected through a 0.2 mm Φ×100 hole round hole nozzle at a spinning temperature of 300°C. The ratio of the ejection speed to the winding speed (draft ratio) was adjusted to 63, and the winding was performed at a winding speed of 666 m / min. The single-filament fineness of the obtained raw yarn was 4.9 dtex. The obtained fibers were evaluated, and the results are shown in Table 1.

[0146]

[0147] As shown in Table 1, Examples 1 to 4 can control the orientation degree and birefringence value of the polycarbonate fiber to a given range by melt spinning at high temperature, and can reduce the dry heat shrinkage rate. Therefore, it is possible to suppress the resin unevenness, warping, deformation and other undesirable conditions of the melt-molded body. In addition, in these examples, even when the fiber diameter is small, the coefficient of variation of the fiber diameter can be reduced, and the handling property is also good. The obtained fiber has a strength that is not a problem in practical use, and has a high elongation, and further, the flame retardancy is also improved.

[0148] On the other hand, Comparative Example 1 not only has a high molecular weight and poor melt spinnability, but also cannot control the orientation degree and birefringence value of the obtained fiber, and has a large dry heat shrinkage. Therefore, it is difficult to suppress the resin unevenness, warping, deformation and other defects of the melt-molded product. In addition, in Comparative Example 1, since the coefficient of variation of the fiber diameter is high, there is fiber unevenness and poor handling.

[0149] Although the melt spinnability of Comparative Example 2 is good, the orientation degree and birefringence value of the obtained fiber are outside the range of the present invention, and the dry heat shrinkage is large. Therefore, it is difficult to suppress the resin unevenness, warping, deformation and other defects of the melt-molded product. In addition, since the coefficient of variation of the fiber diameter in Comparative Example 2 is higher than that in the Examples, the handling property is inferior to that in the Examples.

[0150] The melt spinnability of Comparative Example 3 is poor, the orientation degree and birefringence value of the obtained fiber are outside the range of the present invention, and the dry heat shrinkage is large. Therefore, it is difficult to suppress the resin unevenness, warping, deformation and other defects of the melt-molded product. In addition, in Comparative Example 3, since the coefficient of variation of the fiber diameter is higher than that of the examples, the handling property is inferior to that of the examples.

[0151] Industrial Applicability

[0152] The fiber structure formed by the polycarbonate fiber of the present invention can be suitably used for various purposes, and can also be used as a resin composite using the polycarbonate fiber as a matrix by melting. Such fiber structure and resin composite can be extremely effectively used in the fields of general industrial materials, electrical / electronics, civil engineering / construction, aircraft / automobile / railway / ship, agricultural materials, optical materials, medical materials, etc.

[0153] As described above, the preferred embodiments of the present invention have been described, but those skilled in the art can easily conceive of various changes and modifications within an obvious scope after reading the present application specification. Therefore, such changes and modifications are interpreted as being within the scope of the invention defined by the claims.

Claims

1. A polycarbonate fiber, wherein the degree of orientation ft represented by the following formula is less than 0.70, and the weight average molecular weight Mw of the polycarbonate resin constituting the polycarbonate fiber is 45000 to 80000, ft=1-(1.0 / C) 2 C: The measured value of the speed of sound, the unit of the speed of sound is km / second.

2. A polycarbonate fiber, wherein the degree of orientation ft represented by the following formula is less than 0.70, and the birefringence value is less than 0.040, and the weight average molecular weight Mw of the polycarbonate resin constituting the polycarbonate fiber is 45000 to 80000, ft=1-(1.0 / C) 2 C: The measured value of the speed of sound, the unit of the speed of sound is km / second.

3. The polycarbonate fiber according to claim 1 or 2, wherein: The number average molecular weight Mn of the polycarbonate resin constituting the polycarbonate fiber is 12,000 to 40,000.

4. A polycarbonate fiber having a birefringence value of 0.040 or less and formed from a polycarbonate resin, wherein: The weight average molecular weight Mw of the polycarbonate resin constituting the polycarbonate fiber is 45,000 to 80,000.

5. The polycarbonate fiber according to claim 4, wherein The number average molecular weight Mn of the polycarbonate resin constituting the polycarbonate fiber is 12,000 to 40,000.

6. The polycarbonate fiber according to claim 1, 2 or 4, which has a molecular weight distribution Mw / Mn of 2.0 to 4.

0.

7. The polycarbonate fiber according to claim 1, 2 or 4, wherein: The elastic modulus of the fiber is 30 cN / dtex or less.

8. The polycarbonate fiber according to claim 1, 2 or 4, wherein The coefficient of variation of the fiber diameter was 15% or less.

9. The polycarbonate fiber according to claim 1, 2 or 4, which has a single fiber fineness of 10 dtex or less.

10. The polycarbonate fiber according to claim 1, 2 or 4, wherein The breaking elongation of the fiber is more than 20%.

11. The polycarbonate fiber according to claim 1, 2 or 4, wherein: In the monomer units in the polycarbonate-based resin, the ratio of the bisphenol A skeleton to the whole is 65% or more in terms of mol%.

12. The polycarbonate fiber according to claim 1, 2 or 4, comprising a phosphorus-based flame retardant. 13 . The polycarbonate fiber according to claim 12 , comprising at least one phosphorus-based flame retardant selected from the group consisting of a phosphate-based flame retardant, a phosphate-based flame retardant, and a phosphazene-based flame retardant. 14 . A fiber structure comprising the polycarbonate fiber according to claim 1 .

15. The fiber structure according to claim 14, which is a mixed filament, a woven fabric, or a nonwoven fabric.

16. A method for producing polycarbonate fibers, the method comprising: A melt kneading step of melt kneading a polycarbonate resin having a weight average molecular weight Mw of 45,000 to 80,000 at a high temperature of 305° C. or higher to obtain a molten polymer; An ejection step of ejecting the molten polymer in a given amount from a spinning nozzle; as well as The winding process is to wind up the ejected yarn at a given pulling speed.

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