JP2023001834A - Polyester resin composition, fiber, and film - Google Patents

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

Polyester resins represented by polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), etc. have excellent mechanical and chemical properties and are used in a wide range of fields (for example, clothing and industrial applications). fibers for materials, films or sheets for packaging and magnetic tape, bottles that are hollow molded products, casings for electrical and electronic parts, and other engineering plastic molded products).

In film applications, it is known to add fine particles to the polyester resin to add moderate unevenness to the surface and impart properties such as anti-blocking property and releasability. In addition, in fiber applications, it is known to add inorganic oxide fine particles such as silica and titanium oxide to polyester resins to impart coolness, anti-see-through properties, heat retention and the like to woven and knitted fabrics.

For example, Patent Document 1 discloses a polyester resin composition containing silica particles for obtaining a polyester fiber having excellent heat retention.

JP 2012-57129 A

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

As a result of intensive studies by the present inventors, it was found that a polyester resin composition containing silica particles having a particle size within a specific range is uniformly dispersed without becoming coarse particles. The present inventors have found that they are excellent in matting properties, hiding properties and surface smoothness, and that they are suitable for polyester fibers and films, and have arrived at the present invention.

That is, the gist of the present invention is as follows (1) to (7).
(1) 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, wherein the content of the silica particles is 0.5. 1 to 20% by mass, the average particle size is 3.0 μm or less and the maximum particle size is 10.0 μm or less in the particle size distribution of silica particles measured by a laser diffraction method, and the haze when formed into a molded body is 40% or more, a polyester resin composition.
(2) The polyester resin composition of (1), wherein the silica particles have a specific surface area of 50.0 m ² /g or less.
(3) The film has a three-dimensional surface roughness (SRa) of 0.02 to 0.06 μm, and the number of projections with a height of 0.5 μm or more is 100/m ² or less, (1) Or the polyester resin composition of (2).
(4) The polyester resin composition according to any one of (1) to (3), wherein the silica particles are spherical silica particles.
(5) The polyester resin composition according to any one of (1) to (4), which has a sulfur component content of 5 to 150 ppm.
(6) A fiber containing the polyester resin composition of any one of (1) to (5).
(7) A film containing the polyester resin composition of any one of (1) to (5).

In the polyester resin composition of the present invention, since the particle size and content of the silica particles contained are within a specific range, the silica particles are uniformly dispersed without becoming coarse, and when formed into a molded body, the gloss is obtained. It has excellent erasability, concealability and surface smoothness, and is suitable for fibers and films.

The polyester resin composition of the present invention will be described in detail below.
The polyester resin composition of the present invention contains a polyester resin and silica particles.
The polyester resin consists of a dicarboxylic acid component containing terephthalic acid as a main component 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.

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 %. If the proportion of terephthalic acid is less than 70 mol%, the crystallinity of the resin composition is lowered, the melting point is lowered, and the operability (hereinafter simply referred to as operability) during melt spinning or film formation is impaired. may decrease.

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 includes trimellitic anhydride, trimellitic acid, pyromellitic acid, 1,4-cyclohexanedicarboxylic acid, sebacic acid, dimer acid, and the like. Derivatives may also be used.
Moreover, the polyester resin may contain an aliphatic lactone as an acid component. Aliphatic lactones include lactones having 4 to 11 carbon atoms and homopolymers or copolymers of two or more thereof. Particularly suitable aliphatic lactones include ε-caprolactone and δ-barrellactone.

The polyester resin contained in the polyester resin composition of the present invention contains ethylene glycol as a glycol component. The ratio of ethylene glycol in the glycol component is preferably 20 mol% or more, more preferably 40 mol% or more, still more preferably 75 mol% or more, and particularly 80 mol% or more, because the crystallinity and heat resistance are further excellent. preferable.
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, dimer diol, ethylene oxide adduct of bisphenol S, ethylene oxide adduct of bisphenol A, and the like can be used.

When the polyester resin contains diethylene glycol as a glycol component, the content thereof is preferably 2 mol % or more, more preferably 5 mol % or more and 15 mol % or less, based on the total glycol components. When the content of diethylene glycol is within the above range, the workability is improved.

When the polyester resin contains triethylene glycol as a glycol component, the content thereof is preferably 0.4 to 6.0 mol % of the total glycol components, since the workability is further improved.

When the polyester resin contains tetraethylene glycol as a glycol component, the content is preferably 2 mol % or less because the properties of fibers, films, and the like are further improved.

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 content of silica particles is less than 0.1% by mass, matting and concealing properties of molded articles, fibers, films, and the like will be insufficient. On the other hand, when the content of silica particles exceeds 20% by mass, aggregation of silica particles occurs, and coarse silica particles having a particle diameter of 5 μm or more are generated, and in fibers, the operability deteriorates due to cut threads and the strength decreases. It may be the cause. In addition, in molded articles such as films, coarse silica particles may cause deterioration in the appearance and the like.

In the polyester resin composition of the present invention, it is preferable to use spherical silica particles as the silica particles. As a result, agglomeration is less likely to occur in the resin composition, and the silica particles are uniformly dispersed without becoming coarse. As a result, the average particle size and maximum particle size of silica particles, the haze when made into fibers and films, the three-dimensional surface roughness and the number of protrusions can be easily set within specific ranges, and the matting properties, hiding properties, surface smoothness, and workability , strength, guide frictional properties, etc. are further improved.
The sphericity of the silica particles used in the present invention is, for example, preferably 0.8 or more, more preferably 0.9 or more, and even more preferably 0.95 or more.

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, in a particle size distribution measured by a laser diffraction method. , 0.2 to 2.3 μm. When the average particle size of the silica particles exceeds 3.0 μm, the workability, the strength of the resulting product, and the guide friction properties deteriorate. In addition, the pressure may increase quickly during filtering. If the average particle size of the silica particles is less than 0.1 μm, the effect of containing the silica particles may not be imparted or the concealability may be insufficient when the fiber or film is made.

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 preferably 6 µm or less in the particle size distribution measured by a laser diffraction method. more preferred. When the maximum particle size of silica particles exceeds 10 μm, surface smoothness, runnability, strength, and guide friction deteriorate. Or, the pressurization at the time of filtering may become faster.

Silica particles preferably have a small specific surface area. The specific surface area is preferably 50 m ² /g or less, more preferably 40 m ² /g or less, even more preferably 30 m ² /g or less. If the specific surface area exceeds 50 m ² /g, aggregation may easily occur in the resin composition. As a result, the silica particles tend to be coarse and difficult to disperse uniformly, making it difficult to set the average particle size and maximum particle size of the silica particles, the three-dimensional surface roughness and the number of protrusions when made into fibers and films in specific ranges, and the surface May be inferior in smoothness, runnability, strength, and guide friction. The lower limit of the specific surface area of silica particles is preferably 0.1 m ² /g.

When the polyester resin composition of the present invention is formed into a molded article, the haze is 40% or more, preferably 60% or more, and more preferably 80% or more. If the haze is less than 40%, the matte properties and hiding properties will be poor. A method for calculating the haze will be described in detail in Examples.

When the polyester resin composition of the present invention is used as a film, the three-dimensional surface roughness (SRa) of the film surface is preferably 0.02 to 0.06 μm, and preferably 0.03 to 0.05 μm. more preferred. If the SRa is less than 0.02 μm, the workability may be lowered, and the surface smoothness may be insufficient when used as a fiber or film. If the SRa exceeds 0.06 µm, the runnability may deteriorate. In addition, the pressure may increase quickly during filtering.

When the polyester resin composition of the present invention is made into a film, the number of protrusions having a height of 0.5 μm or more is preferably 100/m ² or less, more preferably 60/m ² or less, and 20 It is more preferable that it is pcs/m ² or less. If the number of protrusions exceeds 100/m ² , the workability may deteriorate. Alternatively, the pressurization during filtering may be faster.
The method of calculating the three-dimensional surface roughness (SRa) of the film surface and the number of protrusions will be described in detail in Examples.

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 preferably 0.6 to 0.8 dl/g. More preferred. If the intrinsic viscosity is less than 0.45 dl/g, sufficient strength and properties may not be obtained when used as a film, fiber, or the like.

In addition, the intrinsic viscosity in the present invention is a value measured at a temperature of 20° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent.

The polyester resin composition of the present invention contains any polymer, antistatic agent, antifoaming agent, dyeability improver, dye, pigment, matting agent, fluorescent brightening agent, as long as the effects of the present invention are not impaired. It may contain stabilizers, antioxidants, colorants, flame retardants and other additives. Examples of antioxidants include aromatic amine-based and phenol-based antioxidants. Examples of stabilizers include phosphorus-based stabilizers such as phosphoric acid or phosphate-based stabilizers, sulfur-based stabilizers, and amine-based stabilizers.

The polyester resin composition of the present invention may contain organic, inorganic, or organometallic toners, fluorescent brighteners, and the like as long as the effects of the present invention are not impaired. Thereby, coloring such as yellowing of the polyester resin can be further suppressed. Alternatively, in order to improve the crystallinity, other resins such as polyethylene and inorganic nucleating agents such as talc may be contained.

The polyester resin composition of the present invention may contain a cobalt compound for the purpose of improving color tone, etc., as long as the effects of the present invention are not impaired. The cobalt compound is not particularly limited, but specific examples thereof include cobalt acetate, cobalt nitrate, cobalt chloride, cobalt acetylacetonate, cobalt naphthenate, and hydrates thereof. Among them, 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 still more preferably 3 ppm or less relative to the polyester resin in terms of cobalt atoms.

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

(Method for producing polyester resin composition)
The method for producing the polyester resin composition of the present invention comprises, for example, an esterification reaction or a transesterification reaction followed by a polycondensation reaction.

The polyester raw material of the polyester resin composition includes, for example, a glycol component containing ethylene glycol as a main component, a dicarboxylic acid component, and an esterified product as a low-order condensate composed of a glycol component and a dicarboxylic acid component.

As a method for obtaining the esterified product, for example, when producing polyethylene terephthalate as a polyester resin, terephthalic acid, ethylene glycol, and if necessary, other copolymer components are directly reacted to distill off water to obtain an ester. to obtain an esterified product as a raw material for a polyester resin. Alternatively, dimethyl terephthalate, ethylene glycol and, if necessary, other copolymer components are reacted to distill off the methyl alcohol and transesterify to obtain an esterified product.

The method for preparing the esterified product will be described below.
A slurry containing ethylene glycol in an amount of preferably 1.02 to 2.5 mol, more preferably 1.03 to 1.8 mol per 1 mol of dicarboxylic acid or ester derivative thereof is prepared. It is continuously supplied to an esterification reactor to obtain an esterified product.

The esterification reaction is carried out under the condition that ethylene glycol is refluxed while removing water or alcohol produced by the reaction out of the system in a rectifying column. The esterification reaction can be carried out using a multi-stage apparatus in which multiple esterification reactors are connected in series.

The temperature of the esterification reaction in the first stage is preferably 240 to 270°C, more preferably 245 to 265°C. The pressure is preferably 0.2-3 kg/cm ² G, more preferably 0.5-2 kg/cm ² G.

The temperature of the esterification reaction in the final stage is preferably 250 to 290°C, more preferably 255 to 275°C. The pressure is preferably 0-1.5 kg/cm ² G, more preferably 0-1.3 kg/cm ² G.

When the reaction is carried out in three or more stages, the reaction conditions for the esterification reaction in the intermediate stage are preferably between the reaction conditions in the first stage and the reaction conditions in the final stage.
It is preferable that the reaction rate of the multistage esterification reaction be smoothly increased in each stage. The final esterification reaction rate preferably reaches 90% or more, more preferably 93% or more. Esterified products can be obtained by these esterification reactions, and the preferred molecular weight thereof is about 500 to 5,000.

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

Silica particles and a polycondensation catalyst are added to the esterified product obtained as described above, and then the polycondensation reaction is allowed to proceed to obtain the polyester resin of the present invention.

A metal compound may be used as the polymerization catalyst. Examples include germanium, antimony, titanium and cobalt compounds, their oxides, inorganic acid salts, organic acid salts, halides and sulfides.
When a metal compound is used as a polymerization catalyst, the amount added is preferably 0.1×10 ⁻⁵ mol to 10.0×10 ⁻⁴ mol per 1 mol of the total acid component of the resulting polyester resin, and 5× 10 ⁻⁵ mol to 3.0×10 ⁻⁴ mol are more preferred. If it is less than 0.1×10 ⁻⁵ , the target degree of polymerization may not be obtained. On the other hand, if it exceeds 10.0×10 ⁻⁴ mol, the stability over time may be deteriorated due to by-products, and the intrinsic viscosity may be lowered and the color tone may be deteriorated after long-term storage.

When the content of the metal component derived from the metal catalyst in the polyester resin composition of the present invention is large, foreign matter may be generated during melt processing. The content of the metal component is preferably 1 ppm or less, more preferably 0.5 ppm or less, and even more preferably 0 ppm.

An organic sulfonic acid compound may be used as the polymerization catalyst. Thereby, a polyester resin composition having a reduced metal component content can be obtained. 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-dinitrobenzenesulfonic 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 Acid anhydride, 1-sulfonaphthoic anhydride, 8-sulfonaphthoic anhydride, 3,6-disulfophthalic anhydride, 4,6-disulfoisophthalic anhydride, 2,5-disulfoterephthalic anhydride, methane sulfonic acid, ethanesulfonic acid, methionic acid, cyclopentanesulfonic acid, 1,1-ethanedisulfonic acid, 1,2-ethanedisulfonic acid, 1,2-ethanedisulfuric acid phonic anhydride, 3-propanedisulfonic acid, β-sulfopropionic acid, isethionic acid, dithionic acid, dithionic 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 the like, and These salts are mentioned. Among them, from the viewpoint of versatility, 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, methyl p-toluenesulfonate, 5-sulfoisophthalic acid, and salts thereof.

The organic sulfonic acid compound can be added, for example, in the form of a solid, a slurry, or a solution dissolved in water, glycol, or the like.

Although the amount of the organic sulfonic acid compound to be added depends on the type, it is preferably 0.5×10 ⁻⁴ to 40×10 ⁻⁴ mol per 1 mol of the acid component constituting the polyester resin composition. , 1.0×10 ⁻⁴ to 20.0×10 ⁻⁴ mol.

By setting the addition amount of the organic sulfonic acid compound within the above range, the content of the sulfur component in the obtained polyester resin composition can be preferably 5 to 150 ppm, more preferably 6 to 100 ppm. . If the content of the sulfur component 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 formed into molded articles, films, fibers, and the like. On the other hand, if it exceeds 150 ppm, it may cause coloring of the polyester resin composition.

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

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

Furthermore, at the time of the polycondensation reaction, a hindered phenol-based antioxidant and a phosphorus compound capable of suppressing thermal decomposition of the resin can be added together with the above polymerization catalyst, if necessary.

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), triethylene 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 and the like are used, but tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane is preferred from the viewpoint of effect and cost. These can be used alone or in combination of two or more.

Phosphorus compounds that can be used include, for example, phosphorous acid, phosphoric acid, trimethylphosphite, triphenylphosphite, tridecylphosphite, trimethylphosphate, tridecylphosphate, and triphenylphosphate. These can be used alone or in combination of two or more.

If necessary, depolymerization reaction and etherification reaction may be performed before the polycondensation reaction.
The reaction conditions for depolymerization are not particularly limited, but the temperature is preferably 240 to 290°C, more preferably 250 to 280°C. The pressure is preferably normal pressure or pressurized, and the pressure is preferably 0 to 3.0 kg/cm ² G.

The etherification reaction is a reaction in which a polymerization catalyst is added and heated to promote the production of etherified products of glycol (diethylene glycol, triethylene glycol, tetraethylene glycol). The etherification reaction temperature is preferably 240°C or higher, more preferably 240 to 300°C. The etherification reaction time is preferably 5 to 120 minutes, more preferably 10 to 60 minutes. Moreover, the etherification reaction is preferably allowed to proceed under normal pressure or increased pressure, and the pressure is preferably 0 to 3.0 kg/cm ² G.

(Application)
The polyester resin composition of the present invention can be applied to various uses. Applications include, for example, fibers, moldings, and films.

The fiber of the present invention can be produced using the polyester resin composition of the present invention.
The fiber of the present invention can be obtained, for example, by melting and spinning a raw material containing the resin composition of the present invention. Spinning can be carried out according to known conditions.

The fibers of the present invention containing the resin composition of the present invention may be, for example, monofilaments, multifilaments, or the like, and may be long fibers, short fibers, or the like.
The shape of the single fiber constituting the fiber of the present invention is not particularly limited, and may be not only a circular cross section but also an irregular cross section such as a polygonal shape.
The fiber of the present invention includes not only fibers in which all of the single fibers are formed of the resin composition of the present invention, but also the resin composition of the present invention and a polyester resin composition other than the resin composition of the present invention (for example, It may be a conjugate fiber with a polyester resin containing other copolymer components. Examples of the form of the composite fiber include a core-sheath type, a side-by-side type, and a sea-island type.

The content of the resin composition of the present invention in the fiber of the present invention is preferably 50% by mass or more, more preferably 80% by mass or more, and more preferably 100% by mass.
By containing the resin composition of the present invention, the fiber of the present invention becomes a fiber excellent in matting properties, hiding properties and surface smoothness.
More specifically, the L value is preferably from 40 to 70, more preferably from 50 to 60, as an indicator of excellent matting and hiding properties.

In addition, the L value in the present invention is obtained by knitting the obtained fiber into a tubular knitted fabric using a knitting machine (manufactured by Koike Kikai Seisakusho, number of needles: 300, hook diameter: 3.5 inches), with a blackboard as the background. It is measured with a color difference meter (CR-300; manufactured by Konica Minolta).

In addition, the fiber of the present invention also has excellent surface smoothness. Excellent surface smoothness reduces the frictional resistance caused by guides, etc., and improves operability. That is, in the spinning, drawing, and processing steps, the generation of fuzz due to the frictional resistance of guides and the like and broken yarn are suppressed, and the obtained fiber has less fuzz.

When the fiber of the present invention is a multifilament, its characteristic values are, for example, a single filament fineness of 0.3 to 30 decitex, a single filament number of 2 to 300, a total fineness of 5 to 350 decitex, a strength of 1 to 5 cN/dtex, and an elongation. Those having a range of 10 to 400% are included.
The fibers of the present invention may be, for example, ultrafine fibers having a single filament fineness of 0.8 decitex or less (preferably 0.6 to 0.3 decitex).

The polyester resin composition of the present invention can be used to produce the film of the present invention.
A method for producing a film from the polyester resin composition of the present invention is not particularly limited, but examples thereof include a method of melting a raw material containing the polyester resin composition of the present invention and melt extruding from a T-die.

To obtain a film by melt extrusion, for example, a sheet extruded from a T-die is brought into close contact with a cooling drum whose temperature is adjusted to 30° C. or less by a known method such as an electrostatic casting method or an air knife method. , to be rapidly solidified to a temperature below the glass transition temperature.

The film may be unstretched, uniaxially stretched or biaxially stretched.
As the biaxial stretching method, a known method such as a tenter simultaneous biaxial stretching method, a tubular simultaneous biaxial stretching method, and a sequential biaxial stretching method can be used. Although the thickness of the film is not particularly limited, it is preferably in the range of 5 to 500 μm.

EXAMPLES The present invention will be specifically described below based on examples, but the present invention is not limited to these. Measurement and evaluation were performed by the following methods.

(1) Intrinsic viscosity Measured at a temperature of 20°C using an equal weight mixture of phenol and ethane tetrachloride as a solvent.

(2) Composition of polyester resin Dissolve 10 mg of sample in 1 mL of a mixed solvent of deuterated chloroform / deuterated trifluoroacetic acid = 9/1 (mass ratio), and ¹ by LA-400 type NMR manufactured by JEOL Ltd. H-NMR was measured, and the total amount of the dicarboxylic acid component, the triethylene glycol component and the tetraethylene glycol component, and the moles of each other glycol component from the peak integrated intensity of the protons of each component in the obtained chart. A ratio was calculated.
Then, triethylene glycol and tetraethylene glycol were quantified as follows.
A polyester resin was hydrolyzed in a potassium hydroxide/methanol solution having a concentration of 0.75 N, and then neutralized by adding terephthalic acid. Next, the filtrate obtained by filtration was measured by gas chromatography, and the molar ratio between triethylene glycol and tetraethylene glycol was calculated using a calibration curve prepared in advance. From these molar ratios and the ¹ H-NMR measurement results described above (the molar ratio of the total component of triethylene glycol and tetraethylene glycol to each glycol component), triethylene glycol, tetraethylene glycol, and tetraethylene glycol in all glycol components. The content of ethylene glycol was calculated.

(3) Content of silica particles, content of sulfur component The polyester resin composition was melt-molded at 300 ° C. to form a disk-shaped molded plate with a diameter of 3 cm × thickness of 1 cm, and a fluorescent X-ray analyzer ZSX Primus manufactured by Rigaku. Quantitative analysis was performed by the calibration curve method.

(4) Average Particle Diameter and Maximum Particle Diameter of Silica Particles A polyester resin composition containing silica particles is dissolved in a mixed solvent of phenol/tetrachloroethane = 50/50% by mass so as to be 5% by mass. The obtained solution was diluted with the same solvent and adjusted so that the diffracted/scattered light intensity was within the range of 40 to 60%, and measured by SALD-7100 manufactured by Shimadzu Corporation, which is a laser diffraction particle size distribution analyzer. Then, the average value of the four measurements was taken as the measured value.

(5) Haze The molded articles obtained in each example and comparative example were used as test pieces, and the haze (turbidity) was measured with a turbidity meter MODEL 1001DP manufactured by Nippon Denshoku Industries Co., Ltd. (air: haze 0%).

(6) Three-dimensional surface roughness (SRa) of the film, number of projections on the film surface For the films obtained in each example and comparative example, a stylus type surface roughness meter (SURFCORDERET-30K) manufactured by Kosaka Laboratory Co., Ltd. was measured 5 times, and the average value was obtained. The measurement conditions were as follows: stylus tip radius 2 μm, weight 20 mg, longitudinal magnification 20000, lateral magnification 200, cutoff 0.25 mm, feed pitch 20 μm, measurement length 1.3 mm, measurement area 0.1 mm ² , measurement speed 100 μm/sec, The hysteresis was 12.5 nm and the count mode was simple.
The projection height was calculated based on the cut surface where the area ratio of the cut end by the cut surface is 70%. The number of protrusions with a height of 0.5 μm or more measured under the above conditions was converted to the number per 1 mm ² and used as the number of protrusions on the film surface.

(7) Fiber Strength and Elongation The strength and elongation of the obtained multifilament yarn were measured according to JIS L 1013 using Tensilon RTC-1210 (manufactured by Orientec).

(8) L value of fiber The obtained multifilament yarn is knitted into a tubular knitted fabric using a knitting machine (manufactured by Koike Kikai Seisakusho, number of needles: 300, hook diameter: 3.5 inches), with a blackboard as the background. It was measured using a color difference meter (CR-300; manufactured by Konica Minolta).

(9) Workability Using the obtained multifilament yarn, the number of fluffs per 25,000 m was measured with a warper. The number of fluff per 25,000 m of 1 or less was rated as acceptable (○), and the number of fluff of 2 or more per 25,000 m was rated as unacceptable (x).

Example 1
A slurry of terephthalic acid and ethylene glycol (molar ratio: 1/1.6) was continuously supplied to an esterification reactor, and reacted at a temperature of 250°C and a pressure of 0.2 MPa, with a residence time of 8 hours. An esterified product (terephthalic acid: ethylene glycol = 100:111 (molar ratio)) was obtained.
The heat-melted esterified product was put into a polycondensation reactor heated to 280° C., and then ADMAFINE SO-C2 (made by Admatechs Co., Ltd., spherical silica particles) (average primary particle size: 0.5 μm, Specific surface area: 6.0 m ² /g) was added to ethylene glycol so that the concentration of silica particles was 50% by mass, and agitation and dispersion treatment was performed using a homojetter manufactured by Tokushu Kika Kogyo Co., Ltd. to obtain a coarse dispersion. The resulting coarse dispersion was passed through SONIC. Predetermined time dispersion processing was performed using a CORP sonolator. The dispersion of silica particles and ethylene glycol thus prepared was added to the esterification reaction product so that the content of silica particles in the polyester resin composition was 1.5% by mass. Then, after performing a depolymerization reaction for 1 hour, 5-sulfosalicylic acid dihydrate (SS) was added as a polycondensation catalyst at 2.0×10 ⁻⁴ mol/acid component mol, and the temperature was maintained at 280° C. under normal pressure. The etherification reaction was carried out at rt for 10 minutes. Next, while maintaining the temperature of the reactor at 280° C., the system pressure was gradually reduced to 0.5 hPa or less after 60 minutes. A polycondensation reaction was carried out for 3 hours while stirring under these conditions to obtain a polyester resin composition.

[Production of molded bodies in Examples 1 to 10 and Comparative Examples 1 to 4]
After drying the obtained polyester resin composition, a small injection molding machine was set to 230 to 280°C for each part of the cylinder and nozzle temperature, 100 rpm for screw rotation, 10 seconds for injection, 10 seconds for cooling, and 20°C for mold temperature. (Nissei Plastic Industry Co., Ltd., PS-20) was used to prepare an injection molded body (50 × 50 × 1 mm flat plate).

[Production of films in Examples 1 to 10 and Comparative Examples 1 to 4]
The resulting polyester resin composition was melt-extruded into a sheet at 275° C. using an extruder, brought into close contact with a cooling drum and cooled to obtain an unstretched sheet having a thickness of 250 μm. The obtained unstretched sheet was subjected to simultaneous biaxial stretching of 3×3.3 times using a batch type stretching apparatus to obtain a film having a thickness of 25 μm.

Examples 2-3 and 5-8, Comparative Examples 1-2
[Polyester resin composition]
A polyester resin composition was obtained in the same manner as in Example 1, except that the amount of silica particles and the amount of sulfosalicylic acid dihydrate added were changed as shown in Table 1. Further, the same operation as in Example 1 was performed to prepare a molded article and a film.

Example 4, Comparative Examples 3-4
As silica particles, Example 4 is manufactured by (Admatechs Co., Ltd.), trade name (Admafine SO-C6) (average particle size of primary particles: 2.0 μm, specific surface area: 2.0 m ² /g, spherical Silica particles), Comparative Example 3 (AGC Si Tech), trade name (Sunsphere H31), and Comparative Example 4, amorphous silica were used. A resin composition was obtained. Further, the same operation as in Example 1 was performed to prepare a molded article and a film.

Example 9
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. Further, the same operation as in Example 1 was performed to prepare a molded article and a film.

Example 10
100 parts by mass of the ester compound and then 4.3 parts by mass of isophthalic acid are added to the polycondensation reactor so that the composition of the aromatic dicarboxylic acid component of the polyester resin is 95 mol % terephthalic acid and 5 mol % isophthalic acid. A polyester resin composition was obtained in the same manner as in Example 1, except that Further, the same operation as in Example 1 was performed to prepare a molded article and a film.

Example 11
A slurry of terephthalic acid and ethylene glycol (molar ratio: 1/1.6) was continuously supplied to an esterification reactor, and reacted at a temperature of 250°C and a pressure of 0.2 MPa, with a residence time of 8 hours. An esterified product (terephthalic acid: ethylene glycol = 100:111 (molar ratio)) was obtained.
100 parts by mass of the 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 charged into a polycondensation reactor heated to 260°C, and then ADMAFINE SO-C2. (Made by Admatechs Co., Ltd., spherical silica particles) (average particle size of primary particles: 0.5 μm, specific surface area: 6.0 m ² /g) in ethylene glycol so that the concentration of silica particles becomes 50% by mass. The mixture was charged and dispersed by stirring using a homojetter manufactured by Tokushu Kika Kogyo Co., Ltd. to obtain a coarse dispersion. The resulting coarse dispersion was passed through SONIC. Predetermined time dispersion processing was performed using a CORP sonolator. A dispersion of silica particles and ethylene glycol thus prepared was added to a polycondensation reactor so that the content of silica particles in the polyester resin composition was 1.5% by mass. Then, after performing a depolymerization reaction for 1 hour, 5-sulfosalicylic acid dihydrate (SS) was added as a polycondensation catalyst at 6.0×10 ⁻⁴ mol/acid component mol, and the temperature was maintained at 260° C. under normal pressure. The etherification reaction was carried out at rt for 10 minutes. Next, while maintaining the temperature of the reactor at 260° C., the system pressure was gradually reduced to 0.5 hPa or less after 60 minutes. A polycondensation reaction was carried out for 3 hours while stirring under these conditions to obtain a polyester resin composition.

[Production of molded bodies in Examples 11 to 21]
After drying the obtained polyester resin composition, a small injection molding machine was set to 180 to 240°C for each part of the cylinder and nozzle temperature, 100 rpm for screw rotation, 10 seconds for injection, 10 seconds for cooling, and 20°C for mold temperature. (Nissei Plastic Industry Co., Ltd., PS-20) was used to prepare an injection molded body (50 × 50 × 1 mm flat plate).

[Production of films in Examples 11 to 21]
The obtained polyester resin composition was melt-extruded into a sheet at 240° C. using an extruder, and the sheet was brought into close contact with a cooling drum and cooled to obtain an unstretched sheet having a thickness of 250 μm. The obtained unstretched sheet was subjected to simultaneous biaxial stretching of 3×3.3 times using a batch type stretching apparatus to obtain a film having a thickness of 25 μm.

Example 12
27.9 parts by mass of terephthalic acid, 15.1 parts by mass of 1,4-butylene glycol, the same operation as in Example 11 except changing the depolymerization time to 2 hours, polyester resin composition, molded article , got the film.

Example 13
83.6 parts by mass of terephthalic acid, 45.4 parts by mass of 1,4-butylene glycol, the same operation as in Example 11 except changing the depolymerization time to 4 hours, polyester resin composition, molded article , got the film.

Example 14
Example except that 133.8 parts by mass of terephthalic acid and 72.6 parts by mass of 1,4-butylene glycol are added, 9.1 parts by mass of ε-caprolactone is added, and the depolymerization time is changed to 5 hours. By performing the same operation as in 11, a polyester resin composition, a molded article, and a film were obtained.

Example 15
Example except that 98.4 parts by mass of terephthalic acid and 53.4 parts by mass of 1,4-butylene glycol are added, 24.1 parts by mass of ε-caprolactone is added, and the depolymerization time is changed to 5 hours. By performing the same operation as in 11, a polyester resin composition, a molded article, and a film were obtained.

Example 16
167.2 parts by mass of terephthalic acid, 90.7 parts by mass of 1,4-butylene glycol, 31.5 parts by mass of ε-caprolactone were added, and the depolymerization time was changed to 6 hours. By performing the same operation as in 11, a polyester resin composition, a molded article, and a film were obtained.

Example 17
27.9 parts by mass of terephthalic acid and 15.1 parts by mass of 1,4-butylene glycol were added, and 4 parts of tetra-n-butyl titanate (TBT) was added instead of 5-sulfosalicylic acid dihydrate (SS). A polyester resin composition, a molded product and a film were obtained in the same manner as in Example 11, except that 0×10 ⁻⁴ mol/mole of the acid component was added and the depolymerization time was changed to 2 hours.

Example 18
83.6 parts by mass of terephthalic acid and 45.4 parts by mass of 1,4-butylene glycol were added, and 4 parts of tetra-n-butyl titanate (TBT) was added instead of 5-sulfosalicylic acid dihydrate (SS). A polyester resin composition, a molded article and a film were obtained in the same manner as in Example 11, except that 0×10 ⁻⁴ mol/mole of the acid component was added and the depolymerization time was changed to 4 hours.

Example 19
Tetra- The same operation as in Example 11 was performed except that n-butyl titanate (TBT) was added at 4.0 × 10 ^-4 mol/acid component mol and the depolymerization time was changed to 5 hours, and a polyester resin composition was molded. Body, got the film.

Example 20
Tetra- The same operation as in Example 11 was performed except that n-butyl titanate (TBT) was added at 4.0 × 10 ^-4 mol/acid component mol and the depolymerization time was changed to 5 hours, and a polyester resin composition was molded. Body, got the film.

Example 21
Tetra- The same operation as in Example 11 was performed except that n-butyl titanate (TBT) was added at 4.0 × 10 ^-4 mol/acid component mol and the depolymerization time was changed to 5 hours, and a polyester resin composition was molded. Body, got the film.

[Fabrication of fibers]
Example 22
The polyester resin composition obtained in Example 1 was spun at a spinning temperature of 303° C. using a spinning nozzle (hole diameter 0.2 mm, number of holes 150 holes) equipped with a filter having a filtration particle size of 20 μm using an extruder-type melt spinning machine, A partially oriented yarn was obtained by winding at a spinning speed of 3200 m/min. This was drawn 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., a plate heater (temperature of 150° C.) was provided between the first roller and the second roller, heat treatment was performed, and the film was stretched at a speed of 725 m/min and wound up.

Example 23
A multifilament yarn having 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 having 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.
Example 25
A multifilament yarn having 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 9 was used.
Example 26
A multifilament yarn having 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 having 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.

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 Examples and Comparative Examples.

As shown in Tables 1 and 2, the polyester resin compositions obtained in Examples 1 to 21 had silica particle content, average particle size, and maximum particle size within the ranges specified in the present invention. The haze was high, and the matting and hiding properties were excellent, and the surface roughness and the number of protrusions when formed into a film fell within a specific range, and the surface smoothness was excellent.
Moreover, as shown in Table 3, the multifilament yarns obtained in Examples 22 to 27 were excellent in strength, elongation, concealability and workability, and had little fluff.

On the other hand, in Comparative Example 1, since the content of silica particles was small, the haze was low and the surface roughness of the film was small.

In Comparative Example 2, since the content of silica particles was large, the haze was sufficient, but the surface roughness and the number of protrusions of the film were increased.

In Comparative Example 3, since the silica particles used had a large particle size, the haze was sufficient, but the surface roughness and the number of protrusions when formed into a film were increased.

In Comparative Example 4, although the silica particles used had a particle size within the range of the present invention, they were amorphous silica particles rather than spherical silica particles. Both the surface roughness and the number of protrusions increased.

Claims (7)

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 a polyester resin composition containing silica particles,
The content of silica particles is 0.1 to 20% by mass,
In the particle size distribution of silica particles measured by a laser diffraction method, the average particle size is 3.0 μm or less and the maximum particle size is 10.0 μm or less,
A polyester resin composition having a haze of 40% or more when formed into a molded article. The polyester resin composition according to claim 1, wherein the silica particles have a specific surface area of 50.0 ^m2 /g or less. According to claim 1 or 2, the film has a three-dimensional surface roughness (SRa) of 0.02 to 0.06 μm, and the number of protrusions with a height of 0.5 μm or more is 100/m ² or less. The polyester resin composition described. The polyester resin composition according to any one of claims 1 to 3, wherein the silica particles are spherical silica particles. The polyester resin composition according to any one of claims 1 to 4, wherein the sulfur component content is 5 to 150 ppm. A fiber containing the polyester resin composition according to any one of claims 1 to 5. A film containing the polyester resin composition according to any one of claims 1 to 5.