Polyester resin compositions, fibers, and films

Abstract

To provide a polyester resin composition in which silica particles are dispersed uniformly and which can be used suitably for fiber and film applications.SOLUTION: Provided is a polyester resin composition, comprising: a polyester resin composed of an aromatic dicarboxylic acid component containing terephthalic acid as a main component and a glycol component containing ethylene glycol; and silica particles. A content of the silica particles is 0.1 to 20 mass%. In a particle size distribution of the silica particles measured by a laser diffraction method, an average particle diameter is 3.0 μm or less and the maximum particle size is 10.0 μm or less. When the polyester composition is formed into a molded body, the haze is 40% or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyester resin composition that can be suitably used for fiber and film applications. [Background technology]

[0002] Polyester resins, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN), have excellent mechanical and chemical properties and are used in a wide range of fields (for example, fibers for clothing and industrial materials, films or sheets for packaging and magnetic tapes, hollow molded bottles, casings for electrical and electronic components, and other engineering plastic molded products).

[0003] In film applications, it is known that fine particles are incorporated into polyester resin to create a moderate surface texture, thereby imparting properties such as block resistance and mold release. In textile applications, it is known that inorganic oxide fine particles such as silica and titanium dioxide are incorporated into polyester resin to impart properties such as coolness, opacity, and heat retention to woven or knitted fabrics.

[0004] For example, Patent Document 1 discloses a polyester resin composition containing silica particles for obtaining polyester fibers with excellent heat retention properties. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2012-57129 [Overview of the project] [Problems that the invention aims to solve]

[0006] In recent years, there has been a demand for a polyester resin composition that is excellent in matting property, hiding property, and surface smoothness when formed into a molded article and is suitable for fibers and films. An object of the present invention is to provide a polyester resin composition that is excellent in matting property, hiding property, and surface smoothness and is suitable for fibers and films.

Means for Solving the Problems

[0007] As a result of intensive studies by the present inventors, a polyester resin composition containing silica particles having a specific particle size within a specific range is such that the silica particles are uniformly dispersed without becoming coarse particles, and thus is excellent in matting property, hiding property, and surface smoothness and is suitably used for polyester fibers and films. The present invention has been achieved.

[0008] That is, the gist of the present invention is as follows (1) to (5). (1) Terephthalic acid The proportion is 70 mol% or more. A fiber containing a polyester resin composed of an aromatic dicarboxylic acid component and a glycol component containing ethylene glycol and silica particles. Furthermore, the sulfur content is 5-150 ppm. However, the content of the silica particles in the polyester resin composition is 0.1 to 20% by mass, and in the particle size distribution of the silica particles measured by the laser diffraction method, the average particle size is 3.0 μm or less and the maximum particle size is 10.0 μm or less. That is . (2) The fiber according to (1), wherein the specific surface area of the silica particles is 50.0 m / g or less. ( 3 ) The fiber according to any one of (1), wherein the silica particles are spherical silica particles. [[ID=3'2]] or (2)

Advantages of the Invention

[0009] Since the particle size and content of the silica particles contained in the polyester resin composition of the present invention are within a specific range, the silica particles are uniformly dispersed without becoming coarse, and the polyester resin composition is excellent in matting property, hiding property, and surface smoothness when formed into a molded article and is suitable for fibers and films. ​

Mode for Carrying Out the Invention

[0010] Hereinafter, the polyester resin composition of the present invention will be described in detail. The polyester resin composition of the present invention contains a polyester resin and silica particles. The polyester resin is composed of a dicarboxylic acid component mainly containing terephthalic acid and a glycol component containing ethylene glycol. Other dicarboxylic acid components and other glycol components may be copolymerized within a range that does not impair the properties of the resin composition.

[0011] The proportion of terephthalic acid in the acid component is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and particularly preferably 100 mol%. When the proportion of terephthalic acid is less than 70 mol%, the crystallinity of the resin composition decreases, the melting point becomes low, and the operability during melt spinning or film formation (hereinafter simply referred to as operability) may decrease.

[0012] Examples of acid components other than terephthalic acid in the polyester resin include isophthalic acid, phthalic acid, phthalic anhydride, naphthalenedicarboxylic acid, adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, dodecanedioic acid, dimer acid, and further trimellitic anhydride, trimellitic acid, pyromellitic acid, 1,4-cyclohexanedicarboxylic acid, sebacic acid, dimer acid, etc. Two or more of these may be used in combination, or ester-forming derivatives of these acids may be used. Further, the polyester resin may contain an aliphatic lactone as an acid component. Examples of aliphatic lactones include lactones having 4 to 11 carbon atoms and their homopolymers or copolymers of two or more kinds. Particularly preferred aliphatic lactones include ε-caprolactone and δ-valerolactone.

[0013] The polyester resin contained in the polyester resin composition of the present invention contains ethylene glycol as a glycol component. The proportion of ethylene glycol in the glycol component is preferably 20 mol% or more, more preferably 40 mol% or more, even more preferably 75 mol% or more, and particularly preferably 80 mol% or more, as this provides superior crystallinity and heat resistance. Specific examples of glycol components other than ethylene glycol include diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, neopentyl glycol, 1,6-hexanediol, 1,4-butanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, dimergol, ethylene oxide adducts of bisphenol S, ethylene oxide adducts of bisphenol A, and the like.

[0014] When a polyester resin contains diethylene glycol as a glycol component, its content is preferably 2 mol% or more, and more preferably 5 mol% to 15 mol% of the total glycol components. When the diethylene glycol content is within the above range, the operability is superior.

[0015] When the polyester resin contains triethylene glycol as a glycol component, its content is preferably 0.4 to 6.0 mol% of the total glycol component, as this provides superior operability.

[0016] When a polyester resin contains tetraethylene glycol as a glycol component, its content is preferably 2 mol% or less, as this further enhances the properties when it is used in fibers, films, etc.

[0017] The polyester resin composition of the present invention has a silica particle content of 0.1 to 20% by mass, preferably 0.5 to 15% by mass. If the silica particle content is less than 0.1% by mass, the matte finish and opacity of molded articles, fibers, films, etc., will be insufficient. On the other hand, if the silica particle content exceeds 20% by mass, aggregation of silica particles will occur, resulting in coarse silica particles with a particle diameter of 5 μm or more. In the case of fibers, this may cause deterioration of operability due to thread breakage and a decrease in strength. In the case of molded products such as films, the coarse silica particles may cause deterioration of appearance, etc.

[0018] In the polyester resin composition of the present invention, it is preferable to use perfectly spherical silica particles as the silica particles. This makes aggregation less likely to occur in the resin composition, and the silica particles are uniformly dispersed without becoming coarse. As a result, it becomes easier to specify the average particle size and maximum particle size of the silica particles, the haze when made into fibers or films, the three-dimensional surface roughness and the number of protrusions, and the matte finish, opacity, surface smoothness, operability, strength, guide friction, etc. The sphericity of the silica particles used in the present invention is preferably 0.8 or higher, more preferably 0.9 or higher, and even more preferably 0.95 or higher.

[0019] The silica particles contained in the polyester resin composition of the present invention have an average particle size of 3.0 μm or less, preferably 0.1 to 3.0 μm, and more preferably 0.2 to 2.3 μm, as measured by laser diffraction. If the average particle size of the silica particles exceeds 3.0 μm, the operability, strength of the resulting product, and guide friction will deteriorate. In addition, the pressure increase during filter filtration may become faster. If the average particle size of the silica particles is less than 0.1 μm, it may not be possible to impart the effect of containing silica particles when the material is made into fibers or films, or the opacity may be insufficient.

[0020] The silica particles contained in the polyester resin composition of the present invention have a maximum particle size of 10 μm or less, preferably 8 μm or less, and more preferably 6 μm or less, as measured by laser diffraction. If the maximum particle size of the silica particles exceeds 10 μm, surface smoothness, operability, strength, and guide friction deteriorate. Alternatively, the pressure increase during filter filtration may become more rapid.

[0021] Silica particles are preferably small in specific surface area. A specific surface area of ​​50 m² is preferable. 2 It is preferable that the amount be less than or equal to 40m 2 It is more preferable that it be less than or equal to / g, 30m 2 It is even more preferable that the specific surface area be less than or equal to / g. 2 If the amount exceeds 0.1 m², aggregation may occur in the resin composition. As a result, silica particles tend to become coarser and are difficult to disperse uniformly, making it difficult to specify the average particle size, maximum particle size, three-dimensional surface roughness, and number of protrusions when made into fibers or films. This can result in inferior surface smoothness, operability, strength, and guide friction. The lower limit of the specific surface area of ​​silica particles is 0.1 m². 2 It is preferable that it be / g.

[0022] The haze content of a molded article made from the polyester resin composition of the present invention is 40% or more, preferably 60% or more, and more preferably 80% or more. If the haze content is less than 40%, the matte finish and opacity will be poor. The method for calculating the haze content will be described in detail in the examples.

[0023] When the polyester resin composition of the present invention is made into a film, the three-dimensional surface roughness (SRa) of the film surface is preferably 0.02 to 0.06 μm, and more preferably 0.03 to 0.05 μm. If the SRa is less than 0.02 μm, operability may decrease, and the surface smoothness when made into fibers or films may be insufficient. If the SRa exceeds 0.06 μm, operability may deteriorate, and the pressure increase during filter filtration may become rapid.

[0024] When the polyester resin composition of the present invention is made into a film, the number of protrusions with a height of 0.5 μm or more is 100 pieces / m 2 or less, preferably 60 pieces / m 2 or less, more preferably 20 pieces / m 2 or less. If the number of protrusions exceeds 100 pieces / m 2 , the operability may deteriorate. Or the pressure increase during filter filtration may become faster. The method for calculating the three-dimensional surface roughness (SRa) of the film surface and the number of protrusions will be described in detail in the examples.

[0025] The polyester resin composition of the present invention preferably has an intrinsic viscosity of 0.45 dl / g or more, more preferably 0.5 dl / g or more, and even more preferably 0.6 to 0.8 dl / g. If the intrinsic viscosity is less than 0.45 dl / g, sufficient strength and properties may not be obtained when made into a film, fiber, etc.

[0026] The intrinsic viscosity in the present invention is a value measured at a temperature of 20 °C using an equal weight mixture of phenol / tetrachloroethane as a solvent.

[0027] The polyester resin composition of the present invention may contain any polymer, antistatic agent, defoaming agent, dyeing improver, dye, pigment, matting agent, fluorescent whitening agent, stabilizer, antioxidant, colorant, flame retardant, and other additives as long as the effects of the present invention are not impaired. Examples of antioxidants include aromatic amine-based and phenol-based antioxidants. Examples of stabilizers include phosphorus-based, sulfur-based, and amine-based stabilizers such as phosphoric acid or phosphate ester-based stabilizers.

[0028] The polyester resin composition of the present invention may contain organic, inorganic, or organometallic toners, or fluorescent whitening agents, etc. within a range not impairing the effects of the present invention. Thereby, coloring such as yellowing of the polyester resin can be further suppressed. Or to improve crystallinity, it may contain other resins such as polyethylene and inorganic nucleating agents such as talc.

[0029] The polyester resin composition of the present invention may contain a cobalt compound for purposes such as improving color tone, as long as it does not impair the effects of the present invention. The cobalt compound is not particularly limited, but examples include cobalt acetate, cobalt nitrate, cobalt chloride, cobalt acetylacetonate, cobalt naphthenate, and their hydrates. Among these, cobalt acetate tetrahydrate is particularly preferred. The content of the cobalt compound is preferably 10 ppm or less, more preferably 5 ppm or less, and even more preferably 3 ppm or less, as cobalt atoms relative to the polyester resin.

[0030] The polyester resin composition of the present invention may be mixed with waste resin generated during the manufacturing process or recycled polyester resin recovered from the market (for example, PET bottles, etc.).

[0031] (Method for producing polyester resin composition) The method for producing the polyester resin composition of the present invention involves, for example, carrying out a polycondensation reaction after an esterification reaction or a transesterification reaction.

[0032] Examples of polyester raw materials for polyester resin compositions include glycol components containing ethylene glycol as the main component, dicarboxylic acid components, and esterified products as lower-order condensates consisting of glycol components and dicarboxylic acid components.

[0033] As for methods to obtain the above esterified product, for example, when producing polyethylene terephthalate as a polyester resin, terephthalic acid, ethylene glycol, and other copolymer components as needed are reacted directly, water is removed by distillation, and the product is esterified to obtain an esterified product as a raw material for polyester resin. Alternatively, dimethyl terephthalate, ethylene glycol, and other copolymer components as needed are reacted, methyl alcohol is removed by distillation, and the product is transesterified to obtain an esterified product.

[0034] The following describes the method for preparing esterified products. A slurry containing preferably 1.02 to 2.5 moles, more preferably 1.03 to 1.8 moles, of ethylene glycol per mole of dicarboxylic acid or its ester derivative is prepared, and this slurry is continuously supplied to an esterification reactor to obtain an esterified product.

[0035] Esterification reactions are carried out under reflux conditions of ethylene glycol, while removing the water or alcohol produced by the reaction from the system using a rectification column. Esterification reactions can also be carried out using a multi-stage apparatus consisting of multiple esterification reactors connected in series.

[0036] The temperature of the first esterification reaction is preferably 240-270°C, and more preferably 245-265°C. The pressure is 0.2-3 kg / cm². 2 It is preferably G, and 0.5-2 kg / cm³ 2 It is more preferable that it be G.

[0037] The temperature of the final esterification reaction is preferably 250-290°C, and more preferably 255-275°C. The pressure is 0-1.5 kg / cm². 2 It is preferably G, and 0-1.3 kg / cm³ 2 It is more preferable that it be G.

[0038] When the reaction is carried out in three or more stages, the reaction conditions for the intermediate esterification reaction are preferably between the reaction conditions for the first stage and the reaction conditions for the final stage. In multi-step esterification reactions, it is preferable to increase the reaction rate smoothly at each step. Ultimately, the esterification reaction rate should preferably reach 90% or higher, and more preferably 93% or higher. These esterification reactions yield esterified products with a preferred molecular weight of approximately 500 to 5000.

[0039] When terephthalic acid is used in an esterification reaction, the reaction proceeds due to the catalytic action of terephthalic acid as an acid.

[0040] To the esterified product obtained as described above, silica particles and a polycondensation catalyst are added, and then the polycondensation reaction is carried out to obtain the polyester resin of the present invention.

[0041] Metal compounds may be used as polymerization catalysts. Examples include germanium, antimony, titanium and cobalt compounds, their oxides, inorganic salts, organic salts, halides, and sulfides. When a metal compound is used as a polymerization catalyst, the amount added is 0.1 × 10⁻¹⁶ per mole of the total acid component of the resulting polyester resin. -5 Moles ~10.0 × 10 -4 Moles are preferred, 5 × 10 -5 Moles ~3.0 × 10 -4 Moles are more preferable. 0.1 × 10 -5 If the amount is less than 10.0 × 10, the target degree of polymerization may not be achieved. -4 When the amount exceeds the molar limit, the presence of by-products can impair stability over time, potentially leading to a decrease in intrinsic viscosity and deterioration of color after long-term storage.

[0042] If the polyester resin composition of the present invention contains a large amount of metal components derived from a metal catalyst, foreign matter may be generated during melt processing. The content of metal components is preferably 1 ppm or less, more preferably 0.5 ppm or less, and even more preferably 0 ppm.

[0043] Organic sulfonic acid compounds may be used as polymerization catalysts. This allows for the production of polyester resin compositions with reduced metal content. Examples of organic sulfonic acid compounds include benzenesulfonic acid, m- or p-benzenedisulfonic acid, 1,3,5-benzenetrisulfonic acid, o-, m- or p-sulfobenzoic acid, benzaldehyde-o-sulfonic acid, acetophenone-p-sulfonic acid, acetophenone-3,5-disulfonic acid, o-, m- or p-aminobenzenesulfonic acid, sulfanilic acid, 2-aminotoluene-3-sulfonic acid, phenylhydroxylamine-3-sulfonic acid, phenylhydrazine-3-sulfonic acid, 1- Nitronaphthalene-3-sulfonic acid, thiophenol-4-sulfonic acid, anisole-o-sulfonic acid, 1,5-naphthalenedisulfonic acid, o-, m- or p-chlorobenzenesulfonic acid, o-, m- or p-bromobenzenesulfonic acid, o-, m- or p-nitrobenzenesulfonic acid, nitrobenzene-2,4-disulfonic acid, nitrobenzene-3,5-disulfonic acid, nitrobenzene-2,5-disulfonic acid, 2-nitrotoluene-5-sulfonic acid, 2-nitrotoluene-4-sulfonic acid, 2- Nitrotoluene-6-sulfonic acid, 3-nitrotoluene-5-sulfonic acid, 4-nitrotoluene-2-sulfonic acid, 3-nitro-o-xylene-4-sulfonic acid, 5-nitro-o-xylene-4-sulfonic acid, 2-nitro-m-xylene-4-sulfonic acid, 5-nitro-m-xylene-4-sulfonic acid, 3-nitro-p-xylene-2-sulfonic acid, 5-nitro-p-xylene-2-sulfonic acid, 6-nitro-p-xylene-2-sulfonic acid, 2,4-dinitrobenzenesulfonic acid, 3,5-dinitroben Zensulfonic acid, o-, m- or p-fluorobenzenesulfonic acid, 4-chloro-3-methylbenzenesulfonic acid, 2-chloro-4-sulfobenzoic acid, 5-sulfosalicylic acid, 4-sulfophthalic acid, 2-sulfobenzoic anhydride, 3,4-dimethyl-2-sulfobenzoic anhydride, 4-methyl-2-sulfobenzoic anhydride, 5-methoxy-2-sulfobenzoic anhydride, 1-sulfonaphthoic anhydride, 8-sulfonaphthoic anhydride, 3,6-disulfophthalic anhydride, 4,6-disulfisophthalic anhydride, 2,Examples include 5-disulfoterephthalic anhydride, methanesulfonic acid, ethanesulfonic acid, methionic acid, cyclopentanesulfonic acid, 1,1-ethanedisulfonic acid, 1,2-ethanedisulfonic acid, 1,2-ethanedisulfonic anhydride, 3-propanedisulfonic acid, β-sulfopropionic acid, isethionic acid, nithionic acid, nithionic anhydride, 3-oxy-1-propanesulfonic acid, 2-chloroethanesulfonic acid, phenylmethanesulfonic acid, β-phenylethanesulfonic acid, α-phenylethanesulfonic acid, ammonium chlorosulfonate, methyl benzenesulfonate, ethyl p-toluenesulfonate, ethyl methanesulfonate, dimethyl 5-sulfosalicylate, trimethyl 4-sulfophthalate, and salts thereof. In particular, from the perspective of versatility, examples include 2-sulfobenzoic anhydride, o-sulfobenzoic acid, m-sulfobenzoic acid, p-sulfobenzoic acid, 5-sulfosalicylic acid, benzenesulfonic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, p-toluenesulfonic acid, p-methyl p-toluenesulfonate, 5-sulfoizophthalic acid, and their salts.

[0044] Organic sulfonic acid compounds can be added, for example, in solid form, slurry form, or as a solution dissolved in water, glycol, etc.

[0045] The amount of organic sulfonic acid compounds added depends on the type, but is approximately 0.5 × 10⁻⁶ per mole of the acid component constituting the polyester resin composition. -4 ~40×10 -4 It is preferable to use moles, 1.0 × 10 -4 ~20.0×10 -4 It is more preferable to use moles.

[0046] By setting the amount of organic sulfonic acid compound added within the above range, the sulfur content in the resulting polyester resin composition can be preferably 5 to 150 ppm, more preferably 6 to 100 ppm. If the sulfur content is less than 5 ppm, the degree of polymerization is difficult to increase, resulting in a resin composition with a small molecular weight, which may result in inferior properties when used as molded articles, films, or fibers. On the other hand, if it exceeds 150 ppm, it may cause discoloration of the polyester resin composition.

[0047] The polyester resin composition of the present invention can be obtained by performing a polycondensation reaction after the esterification reaction. Examples of polycondensation reactions include melt polycondensation reactions. The polycondensation reaction may be carried out in one step or in multiple steps. The conditions for the polycondensation reaction are not particularly limited, but the temperature of the first stage of the polycondensation reaction is preferably 250 to 290°C, and more preferably 260 to 280°C. The pressure is preferably 500 to 20 hPa, and more preferably 200 to 30 hPa.

[0048] In the case of a multi-stage reaction, the temperature of the final polycondensation reaction is preferably 265 to 300°C, and more preferably 275 to 295°C. The pressure is preferably 10 to 0.1 hPa, and more preferably 5 to 0.5 hPa. When the reaction is carried out in three or more stages, the reaction conditions of the intermediate stages are preferably those between the reaction conditions of the first and final stages. It is preferable to smoothly increase the degree of polymerization in each of these stages.

[0049] Furthermore, during the polycondensation reaction, if necessary, a hindered phenol-based antioxidant and a phosphorus compound that can suppress the thermal decomposition of the resin can be added in conjunction with the polymerization catalyst mentioned above.

[0050] Examples of hindered phenol antioxidants include 2,6-di-t-butyl-4-methylphenol, n-octadecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate, tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane, tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, 4,4'-butylidenebis-(3-methyl-6-t-butylphenol), and tri Ethylene glycol-bis[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate], 3,9-bis{2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1'-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, etc., are used, but tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane is preferred in terms of effectiveness and cost. These can be used individually or in combination of two or more.

[0051] Examples of phosphorus compounds that can be used include phosphorous acid, phosphoric acid, trimethyl phosphite, triphenyl phosphite, tridecyl phosphite, trimethyl phosphate, tridecyl phosphate, and triphenyl phosphate. These can be used individually or in combination of two or more.

[0052] If necessary, depolymerization and etherification reactions may be carried out before the polycondensation reaction. The reaction conditions for depolymerization are not particularly limited, but the temperature is preferably 240-290°C, and more preferably 250-280°C. The reaction is preferably carried out under atmospheric pressure or under pressurized pressure, and the pressure is preferably 0-3.0 kg / cm². 2 G is preferable.

[0053] The etherification reaction is a reaction in which a polymerization catalyst is added and heated to promote the formation of glycol ethers (diethylene glycol, triethylene glycol, tetraethylene glycol). The temperature of the etherification reaction is preferably 240°C or higher, and more preferably 240 to 300°C. The duration of the etherification reaction is preferably 5 to 120 minutes, and more preferably 10 to 60 minutes. Furthermore, the etherification reaction is preferably carried out under atmospheric pressure or pressurized pressure, with a pressure of 0 to 3.0 kg / cm². 2 G is preferable.

[0054] (Application) The polyester resin composition of the present invention can be applied to a variety of uses. Examples of applications include fibers, molded articles, films, and the like.

[0055] The polyester resin composition of the present invention can be used to produce the fibers of the present invention. The fibers of the present invention are obtained, for example, by melting a raw material containing the resin composition of the present invention and spinning it. Spinning can be carried out according to known conditions.

[0056] The fibers of the present invention containing the resin composition of the present invention may be monofilaments, multifilaments, etc., and may also be long fibers, short fibers, etc. The shape of the single fibers constituting the fibers of the present invention is not particularly limited, and may be not only round in cross-section but also have irregular cross-sections such as polygonal shapes. The fibers of the present invention may be not only fibers in which all single fibers are formed from the resin composition of the present invention, but may also be composite fibers of the resin composition of the present invention and polyester resin compositions other than the resin composition of the present invention (for example, polyester resins containing other copolymer components). Examples of composite fiber forms include core-sheath type, side-by-side type, and sea-island type.

[0057] The fibers of the present invention preferably contain 50% by mass or more of the resin composition of the present invention, more preferably 80% by mass or more, and more preferably 100% by mass. The fibers of the present invention, by containing the resin composition of the present invention, become fibers with excellent matte finish, opacity, and surface smoothness. More specifically, as an indicator of excellent matte finish and opacity, the L value is preferably 40 to 70, and more preferably 50 to 60.

[0058] In this invention, the L value is determined by knitting the obtained fibers into a tubular knit fabric using a knitting machine (manufactured by Koike Machinery Works, with 300 needles and a 3.5-inch bobbin diameter), and measuring the L value using a colorimeter (CR-300; manufactured by Konica Minolta) with a blackboard as the background.

[0059] Furthermore, the fibers of the present invention also exhibit excellent surface smoothness. This superior surface smoothness reduces frictional resistance from guides and other components, improving operability. Specifically, in spinning, drawing, and processing steps, the generation of fuzz and breakage due to frictional resistance from guides and other components are suppressed, resulting in fibers with less fuzz.

[0060] When the fiber of the present invention is a multifilament, its characteristic values ​​include, for example, a single filament fineness of 0.3 to 30 decitex, a single filament count of 2 to 300, a total fineness of 5 to 350 decitex, a strength of 1 to 5 cN / decitex, and an elongation of 10 to 400%. The fibers of the present invention may be, for example, ultrafine fibers with a single filament fineness of 0.8 decitex or less (preferably 0.6 to 0.3 decitex).

[0061] The polyester resin composition of the present invention can be used to produce the film of the present invention. The method for producing a film from the polyester resin composition of the present invention is not particularly limited, but one example is a method in which a raw material containing the polyester resin composition of the present invention is melted and extruded from a T-die.

[0062] To obtain a film by melt extrusion, for example, a sheet-like material extruded from a T-die is brought into close contact with a cooling drum heated to 30°C or below using a known method such as electrostatic casting or air knife method, and then rapidly cooled and solidified to a temperature below the glass transition temperature.

[0063] The film may be unstretched, uniaxially stretched, or biaxially stretched. Known biaxial stretching methods such as the tenter-type simultaneous biaxial stretching method, the tubular-type simultaneous biaxial stretching method, and the sequential biaxial stretching method can be used. The thickness of the film is not particularly limited, but a range of 5 to 500 μm is preferred. [Examples]

[0064] The present invention will be described in detail below based on examples, but the present invention is not limited thereto. Measurement and evaluation were performed by the following methods.

[0065] (1) Intrinsic viscosity The measurement was performed at 20°C using an equimassive mixture of phenol and tetrachloroethane as the solvent.

[0066] (2) Composition of polyester resin 10 mg of the sample was dissolved in 1 mL of a mixed solvent of deuterated chloroform / deuterated trifluoroacetic acid = 9 / 1 (mass ratio), and the results were obtained by NMR using a JEOL LA-400 NMR spectrometer. 1 ¹H-NMR was measured, and the total amounts of the dicarboxylic acid component, triethylene glycol component, and tetraethylene glycol component, as well as their molar ratios with the other glycol components, were calculated from the integrated proton peak intensities of each component in the resulting chart. Next, triethylene glycol and tetraethylene glycol were quantified as described below. The polyester resin was hydrolyzed in a 0.75 N potassium hydroxide / methanol solution, and then neutralized with terephthalic acid. Next, the filtrate obtained by filtration was measured by gas chromatography, and the molar ratio of triethylene glycol to tetraethylene glycol was calculated using a pre-prepared calibration curve. These molar ratios and the aforementioned 1 The content of triethylene glycol and tetraethylene glycol in the total glycol components was calculated from the results of 1H-NMR measurements (the total components of triethylene glycol and tetraethylene glycol and the molar ratio of each glycol component).

[0067] (3) Silica particle content, sulfur content A polyester resin composition was melt-molded at 300°C to form a disc-shaped molded plate with a diameter of 3 cm and a thickness of 1 cm. Quantitative analysis was performed using the calibration curve method with a Rigaku ZSX Primus X-ray fluorescence analyzer.

[0068] (4) Average particle size and maximum particle size of silica particles A polyester resin composition containing silica particles was dissolved in a phenol / tetrachloroethane mixed solvent of 50 / 50% by mass to a concentration of 5% by mass. The resulting solution was then diluted with the same solvent using a Shimadzu SALD-7100 laser diffraction particle size distribution analyzer so that the diffraction / scattered light intensity was within the range of 40-60%, and measured. The average of four measurements was then used as the measured value.

[0069] (5) Hayes The molded articles obtained in each example and comparative example were used as test specimens, and the haze (turbidity) was measured using a turbidimeter MODEL1001DP manufactured by Nippon Denshoku Industries Co., Ltd. (Air: haze 0%).

[0070] (6) Three-dimensional surface roughness (SRa) of the film, number of protrusions on the film surface For each example and comparative example, the films obtained were measured five times using a stylus-type surface roughness meter (SURFCORDERET-30K) manufactured by Kosaka Laboratory Co., Ltd., and the average value was calculated. The measurement conditions were: stylus tip radius 2 μm, load 20 mg, vertical magnification 20000, horizontal magnification 200, cutoff 0.25 mm, feed pitch 20 μm, measurement length 1.3 mm, measurement area 0.1 mm. 2 The measurement speed was 100 μm / sec, the hysteresis was 12.5 nm, and the counting mode was set to simple. The height of the protrusions was calculated based on the cross-section where the area ratio of the cut surface was 70%. The number of protrusions with a height of 0.5 μm or more measured under the above conditions was calculated as 1 mm. 2 The number of hits was converted to the number of protrusions on the film surface.

[0071] (7) Fiber strength and elongation The strength and elongation of the obtained multifilament yarns were measured using a Tensilon RTC-1210 (manufactured by Orientec Co., Ltd.) in accordance with JIS L 1013.

[0072] (8) L value of fibers The obtained multifilament yarn was knitted into a tubular fabric using a knitting machine (manufactured by Koike Machinery Works, with 300 needles and a 3.5-inch bobbin diameter), and the color was measured using a colorimeter (CR-300; manufactured by Konica Minolta) with a blackboard as the background.

[0073] (9) Operability The number of fuzz particles per 25,000 meters was measured using a warping machine with the obtained multifilament yarn. Yarn with one or fewer fuzz particles per 25,000 meters was considered acceptable (○), and yarn with two or more fuzz particles was considered unacceptable (×).

[0074] Example 1 A slurry of terephthalic acid and ethylene glycol (molar ratio 1 / 1.6) was continuously supplied to an esterification reaction vessel, and the reaction was carried out under conditions of a temperature of 250°C and a pressure of 0.2 MPa, with a residence time of 8 hours to obtain an esterified product (terephthalic acid:ethylene glycol = 100:111 (molar ratio)). The heated and molten esterified product was added to a polycondensation reaction vessel heated to 280°C, and then AdmaFine SO-C2 (manufactured by Admatex Co., Ltd., spherical silica particles) (average particle size of primary particles: 0.5 μm, specific surface area: 6.0 m²) 2 The silica particles ( / g) were added to ethylene glycol to a concentration of 50% by mass, and the mixture was stirred and dispersed using a homojetter manufactured by Tokushu Kika Kogyo to obtain a crude dispersion. The obtained crude dispersion was dispersed for a predetermined time using a sonorator manufactured by SONIC.CORP. The dispersion of silica particles and ethylene glycol prepared in this way was added to the esterification reaction product to a polyester resin composition to a silica particle content of 1.5% by mass. After a depolymerization reaction for 1 hour, 2.0 × 10⁻⁶ 5-sulfosalicylic acid dihydrate (SS) was added as a polycondensation catalyst. -4 The molar ratio of the acid component was added, and the etherification reaction was carried out at atmospheric pressure at 280°C for 10 minutes. Next, while maintaining the temperature of the reaction vessel at 280°C, the pressure of the system was gradually reduced to below 0.5 hPa after 60 minutes. Under these conditions, the polycondensation reaction was carried out with stirring for 3 hours to obtain a polyester resin composition.

[0075] [Example 1~ 7 and 10 , Reference examples 1~2, Manufacturing of molded articles in Comparative Examples 1-4] After drying the obtained polyester resin composition, injection-molded articles (50 × 50 × 1 mm flat plates) were produced using a small injection molding machine (PS-20, manufactured by Nissei Plastic Industrial Co., Ltd.) with the cylinder and nozzle temperatures set to 230-280°C, screw rotation speed to 100 rpm, injection time to 10 seconds, cooling time to 10 seconds, and mold temperature to 20°C.

[0076] [Example 1~ 7 and 10 , Reference examples 1~2, [Film manufacturing in Comparative Examples 1-4] The obtained polyester resin composition was melt-extruded into a sheet at 275°C using an extruder, cooled in close contact with a cooling drum, and an unstretched sheet with a thickness of 250 μm was obtained. The obtained unstretched sheet was subjected to simultaneous biaxial stretching at 3 × 3.3 times using a batch-type stretching device to obtain a film with a thickness of 25 μm.

[0077] Examples 2-3 and 5- 7 , Reference example 1, Comparative Examples 1-2 [Polyester resin composition] A polyester resin composition was obtained by performing the same procedure as in Example 1, except that the amounts of silica particles and sulfosalicylic acid dihydrate added were changed as shown in Table 1. Furthermore, molded articles and films were prepared by performing the same procedure as in Example 1.

[0078] [Table 1]

[0079] Example 4, Comparative Examples 3-4 As for the silica particles, Example 4 uses Admatex Co., Ltd.'s product name (AdmaFine SO-C6) (average particle size of primary particles: 2.0 μm, specific surface area: 2.0 m²). 2 A polyester resin composition was obtained in the same manner as in Example 1, except that the materials used were spherical silica particles ( / g), Sunsphere H31 (manufactured by AGC SI-TEC) in Comparative Example 3, and irregularly shaped silica in Comparative Example 4. Furthermore, molded articles and films were produced by performing the same procedure as in Example 1.

[0080] Reference example 2 A polyester resin composition was obtained in the same manner as in Example 1, except that antimony trioxide (Sb) was used as the polymerization catalyst instead of sulfosalicylic acid dihydrate. Furthermore, molded articles and films were prepared by performing the same procedure as in Example 1.

[0081] Example 10 A polyester resin composition was obtained in the same manner as in Example 1, except that 4.3 parts by mass of isophthalic acid was added to a polycondensation reaction vessel after 100 parts by mass of esterified material, so that the composition of the aromatic dicarboxylic acid components of the polyester resin was 95 mol% terephthalic acid and 5 mol% isophthalic acid. Furthermore, molded articles and films were produced by performing the same procedure as in Example 1.

[0082] Example 11 A slurry of terephthalic acid and ethylene glycol (molar ratio 1 / 1.6) was continuously supplied to an esterification reaction vessel, and the reaction was carried out under conditions of a temperature of 250°C and a pressure of 0.2 MPa, with a residence time of 8 hours to obtain an esterified product (terephthalic acid:ethylene glycol = 100:111 (molar ratio)). 100 parts by mass of heated and melted esterified product, 4.4 parts by mass of terephthalic acid, and 2.4 parts by mass of 1,4-butylene glycol were placed in a polycondensation reaction vessel heated to 260°C, and then AdmaFine SO-C2 (manufactured by Admatex Co., Ltd., spherical silica particles) (average particle size of primary particles: 0.5 μm, specific surface area: 6.0 m²) were added. 2 The silica particles ( / g) were added to ethylene glycol so that the silica particle concentration was 50% by mass, and the mixture was stirred and dispersed using a homojetter manufactured by Tokushu Kika Kogyo to obtain a crude dispersion. The obtained crude dispersion was dispersed for a predetermined time using a sonorator manufactured by SONIC.CORP. The dispersion of silica particles and ethylene glycol prepared in this way was added to a polycondensation reaction vessel so that the silica particle content in the polyester resin composition was 1.5% by mass. After that, a depolymerization reaction was carried out for 1 hour, and then 6.0 × 10⁻⁶ of 5-sulfosalicylic acid dihydrate (SS) was added as a polycondensation catalyst. -4 The molar ratio of the acid component was added, and the etherification reaction was carried out at atmospheric pressure at 260°C for 10 minutes. Next, while maintaining the temperature of the reaction vessel at 260°C, the pressure of the system was gradually reduced to below 0.5 hPa after 60 minutes. Under these conditions, the polycondensation reaction was carried out with stirring for 3 hours to obtain a polyester resin composition.

[0083] [Examples 11~ 16, Reference examples 3~7 [Manufacturing of molded products in] After drying the obtained polyester resin composition, injection-molded articles (50 × 50 × 1 mm flat plates) were produced using a small injection molding machine (PS-20, manufactured by Nissei Plastic Industrial Co., Ltd.) with the cylinder and nozzle temperatures set to 180-240°C, screw rotation speed to 100 rpm, injection time to 10 seconds, cooling time to 10 seconds, and mold temperature to 20°C.

[0084] [Examples 11~ 16, Reference examples 3~7 [Film manufacturing in this field] The obtained polyester resin composition was melt-extruded into a sheet at 240°C using an extruder, cooled in close contact with a cooling drum, and an unstretched sheet with a thickness of 250 μm was obtained. The obtained unstretched sheet was subjected to simultaneous biaxial stretching at 3 × 3.3 times using a batch-type stretching device to obtain a film with a thickness of 25 μm.

[0085] Example 12 The same procedure as in Example 11 was followed, except that terephthalic acid was added in 27.9 parts by mass, 1,4-butylene glycol in 15.1 parts by mass, and the depolymerization time was changed to 2 hours, to obtain a polyester resin composition, a molded article, and a film.

[0086] Example 13 The same procedure as in Example 11 was carried out, except that terephthalic acid was added in 83.6 parts by mass, 1,4-butylene glycol in 45.4 parts by mass, and the depolymerization time was changed to 4 hours, to obtain a polyester resin composition, a molded article, and a film.

[0087] Example 14 The same procedure as in Example 11 was carried out, except that 133.8 parts by mass of terephthalic acid and 72.6 parts by mass of 1,4-butylene glycol were added, 9.1 parts by mass of ε-caprolactone was added, and the depolymerization time was changed to 5 hours, to obtain a polyester resin composition, a molded article, and a film.

[0088] Example 15 The same procedure as in Example 11 was carried out, except that 98.4 parts by mass of terephthalic acid and 53.4 parts by mass of 1,4-butylene glycol were added, 24.1 parts by mass of ε-caprolactone was added, and the depolymerization time was changed to 5 hours, to obtain a polyester resin composition, a molded article, and a film.

[0089] Example 16 The same procedure as in Example 11 was carried out, except that 167.2 parts by mass of terephthalic acid and 90.7 parts by mass of 1,4-butylene glycol were added, 31.5 parts by mass of ε-caprolactone was added, and the depolymerization time was changed to 6 hours, to obtain a polyester resin composition, a molded article, and a film.

[0090] Reference example 3 Add 27.9 parts by mass of terephthalic acid and 15.1 parts by mass of 1,4-butylene glycol, and replace 5-sulfosalicylic acid dihydrate (SS) with tetra-n-butyl titanate (TBT) in a total of 4.0 × 10⁻⁶ parts. -4 The same procedure as in Example 11 was followed, except that the moles / moles of acid component were added and the depolymerization time was changed to 2 hours, to obtain a polyester resin composition, a molded article, and a film.

[0091] Reference example 4 Add 83.6 parts by mass of terephthalic acid and 45.4 parts by mass of 1,4-butylene glycol, and replace 5-sulfosalicylic acid dihydrate (SS) with tetra-n-butyl titanate (TBT) in a total volume of 4.0 × 10⁻⁶. -4 Except for adding molars of the acid component and changing the depolymerization time to 4 hours, the same procedure as in Example 11 was performed to obtain a polyester resin composition, a molded article, and a film.

[0092] Reference example 5 Add 133.8 parts by mass of terephthalic acid and 72.6 parts by mass of 1,4-butylene glycol, then add 9.1 parts by mass of ε-caprolactone and 4.0 × 10⁻¹⁶ parts by mass of tetra-n-butyl titanate (TBT) instead of 5-sulfosalicylic acid dihydrate (SS). -4 The same procedure as in Example 11 was followed, except that the moles of the acid component were added and the depolymerization time was changed to 5 hours, to obtain a polyester resin composition, a molded article, and a film.

[0093] Reference example 6 Add 98.4 parts by mass of terephthalic acid and 53.4 parts by mass of 1,4-butylene glycol, then add 24.1 parts by mass of ε-caprolactone and 4.0 × 10⁻¹⁶ parts by mass of tetra-n-butyl titanate (TBT) instead of 5-sulfosalicylic acid dihydrate (SS). -4 The same procedure as in Example 11 was followed, except that the moles of the acid component were added and the depolymerization time was changed to 5 hours, to obtain a polyester resin composition, a molded article, and a film.

[0094] Reference example 7 Add 167.2 parts by mass of terephthalic acid and 90.7 parts by mass of 1,4-butylene glycol, then add 31.5 parts by mass of ε-caprolactone and 4.0 × 10⁻¹⁶ parts by mass of tetra-n-butyl titanate (TBT) instead of 5-sulfosalicylic acid dihydrate (SS). -4 The same procedure as in Example 11 was followed, except that the moles of the acid component were added and the depolymerization time was changed to 5 hours, to obtain a polyester resin composition, a molded article, and a film.

[0095] [Textile manufacturing] Example 22 The polyester resin composition obtained in Example 1 was spun using an extruder-type melt spinning machine through a spinning nozzle (pore size 0.2 mm, number of holes 150) equipped with a filter with a particle size of 20 μm at a spinning temperature of 303°C, and wound up at a spinning speed of 3200 m / min to obtain a partially oriented yarn. This was then stretched 1.4 times between rollers to obtain a 60 dtex / 150 f multifilament yarn (drawn yarn). At this time, the temperature of the first roller was set to 90°C, and a plate heater (temperature 150°C) was placed between it and the second roller for heat treatment, and the yarn was stretched and wound up at a speed of 725 m / min.

[0096] Example 23 A multifilament yarn with a fineness of 60 dtex / 150 f was obtained in the same manner as in Example 22, except that the polyester resin composition obtained in Example 2 was used. Example 24 A multifilament yarn with a fineness of 60 dtex / 150 f was obtained in the same manner as in Example 22, except that the polyester resin composition obtained in Example 3 was used. Reference example 8 Reference example 2 A multifilament yarn with a fineness of 60 dtex / 150 f was obtained in the same manner as in Example 22, except that the polyester resin composition obtained in was used. Example 26 A multifilament yarn with a fineness of 60 dtex / 150 f was obtained in the same manner as in Example 22, except that the polyester resin composition obtained in Example 10 was used. Example 27 A multifilament yarn with a fineness of 60 dtex / 150 f was obtained in the same manner as in Example 22, except that the polyester resin composition obtained in Example 13 was used.

[0097] Tables 1, 2, and 3 show the characteristic values ​​and evaluation results of the polyester resin compositions, molded articles, films, and multifilament yarns obtained in the examples and comparative examples.

[0098] [Table 2]

[0099] [Table 3]

[0100] As shown in Table 1 and Table 2, Examples 1 to 7 and 10-16, Reference Examples 1-7 The polyester resin composition obtained had silica particle content, average particle size, and maximum particle size within the range defined in this invention, resulting in high haze, excellent matte finish, and superior opacity. When made into a film, the surface roughness and number of protrusions were within a specific range, resulting in excellent surface smoothness. Furthermore, as shown in Table 3, Examples 22~ 24 and 26-27, Reference Example 8 The resulting multifilament yarn exhibited excellent strength, elongation, opacity, and workability, and had minimal fuzz.

[0101] On the other hand, in Comparative Example 1, the silica particle content was low, resulting in a low haze and reduced surface roughness when formed into a film.

[0102] In Comparative Example 2, due to the high silica particle content, although the haze was sufficient, the surface roughness and number of protrusions in the resulting film were increased.

[0103] In Comparative Example 3, because the particle size of the silica particles used was large, the haze was sufficient, but the surface roughness and number of protrusions when it was made into a film were large.

[0104] In Comparative Example 4, although the silica particles used had a particle size within the range of the present invention, they were amorphous rather than perfectly spherical silica particles. As a result, while the haze was sufficient, both the surface roughness and the number of protrusions were increased when the film was formed.

Claims

1. A fiber containing a polyester resin composition comprising a polyester resin consisting of an aromatic dicarboxylic acid component having a terephthalic acid content of 70 mol% or more and a glycol component containing ethylene glycol, and silica particles, wherein the sulfur component content is 5 to 150 ppm. However, the silica particles are contained in the polyester resin composition at a concentration of 0.1 to 20% by mass, and the particle size distribution of the silica particles, as measured by laser diffraction, has an average particle size of 3.0 μm or less and a maximum particle size of 10.0 μm or less.

2. The specific surface area of ​​the silica particles contained in the polyester resin composition is 50.0 m². ２ The fiber according to claim 1, wherein the amount is less than or equal to / g.

3. The fiber according to claim 1 or 2, wherein the silica particles contained in the polyester resin composition are spherical silica particles.

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