阅读说明：本技术 聚缩醛纤维及其制造方法、以及拉伸用材料 (Polyacetal fiber, method for producing same, and material for drawing ) 是由 须长大辅 三上素直 于 2020-11-25 设计创作，主要内容包括：一直以来期待一种纺丝稳定性优异、外观均一的聚缩醛纤维及其制造方法。根据本发明,可以提供一种聚缩醛树脂,其特征在于,相对于聚缩醛树脂100质量份,含有无机填充剂0.05～1.3质量份,上述无机填充剂的一次平均粒径大于0.5μm且为10μm以下,熔体流动指数为15～45g/10min。(Polyacetal fibers having excellent spinning stability and uniform appearance and a method for producing the same have been desired. According to the present invention, there is provided a polyacetal resin comprising 0.05 to 1.3 parts by mass of an inorganic filler per 100 parts by mass of a polyacetal resin, wherein the inorganic filler has a primary average particle diameter of more than 0.5 μm and 10 μm or less and a melt flow index of 15 to 45g/10 min.)

1. A polyacetal fiber, characterized in that:

the polyacetal resin composition contains 0.05-1.3 parts by mass of an inorganic filler having a primary average particle diameter of more than 0.5 μm and not more than 10 μm per 100 parts by mass of the polyacetal resin,

the melt flow index is 15-45 g/10 min.

2. The polyacetal fibers as set forth in claim 1, wherein:

the inorganic filler contains at least one of magnesium and silicon.

3. The polyacetal fibers as set forth in claim 1 or 2, wherein:

the inorganic filler is talc.

4. The polyacetal fibers as set forth in any one of claims 1 to 3, wherein: it is a multifilament.

5. The polyacetal fibers as set forth in claim 4, wherein:

the yarn is multifilament with thickness of 36-400 deniers.

6. The polyacetal fibers as set forth in claim 4 or 5, wherein:

the yarn is a multifilament composed of 12 to 48 monofilaments.

7. The polyacetal fibers as set forth in any one of claims 4 to 6, wherein: the yarn is a multifilament composed of monofilaments with thickness of 1-12 deniers.

8. The polyacetal fibers as set forth in any one of claims 1 to 7, wherein: it is used in woven, knitted or non-woven fabrics.

9. A material for stretching, characterized in that:

the polyacetal resin composition contains 0.05-1.3 parts by mass of an inorganic filler having a primary average particle diameter of more than 0.5 μm and not more than 10 μm per 100 parts by mass of the polyacetal resin,

the melt flow index is 15-45 g/10 min.

10. A method for producing a polyacetal fiber, characterized in that:

a polyacetal fiber is produced from a polyacetal resin composition by a melt spinning method,

the polyacetal resin composition comprises 0.05-1.3 parts by mass of an inorganic filler per 100 parts by mass of a polyacetal resin, wherein the inorganic filler has a primary average particle diameter of more than 0.5 [ mu ] m and 10 [ mu ] m or less, and the polyacetal resin composition has a melt flow index of 15-45 g/10 min.

Technical Field

The present invention relates to a polyacetal fiber containing a polyacetal resin and an inorganic filler, a method for producing the same, and a material for stretching containing the polyacetal resin and the inorganic filler.

Background

The polyacetal is also called as an oxymethylene polymer, and there are copolymers obtained by polymerizing a homopolymer of formaldehyde and a cyclic oligomer such as trioxane with a comonomer.

The polyacetal has an excellent balance among mechanical properties, chemical resistance, slidability, etc., and is easy to process. Therefore, engineering plastics are widely used as typical engineering plastics, mainly for electric and electronic parts, automobile parts, and other various mechanical parts. However, the polyacetal has physical properties such as high crystallinity, and thus it is difficult to apply the polyacetal to fibers and stretched materials. Further, there is a problem that unevenness in fineness is likely to occur in polyacetal fibers.

In order to solve the above problems, patent document 1 discloses a polyoxymethylene fiber comprising a polyoxymethylene copolymer, wherein the polyoxymethylene copolymer is cooled from a molten state at 200 ℃ to 150 ℃ at a cooling rate of 80 ℃/min, and the semicrystallization time is 30 seconds or more when the polyoxymethylene copolymer is held at 150 ℃. However, in the case of the fiber disclosed in patent document 1, when a polyoxymethylene copolymer is melt-spun to produce a polyoxymethylene fiber, it is necessary to draw out a fibrous material discharged from a discharge nozzle of a melt-spinning apparatus while heating the fibrous material at 140 to 250 ℃ during spinning, which is troublesome in operation.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2003-089925

Disclosure of Invention

Problems to be solved by the invention

Polyacetal fibers having excellent spinning stability and uniform appearance and a method for producing the same have been desired.

Means for solving the problems

According to the present invention, the following embodiments are provided.

[1] A polyacetal fiber, characterized in that:

contains 0.05 to 1.3 parts by mass of an inorganic filler per 100 parts by mass of a polyacetal resin,

the inorganic filler has a primary average particle diameter of more than 0.5 μm and not more than 10 μm,

the melt flow index is 15-45 g/10 min.

[2] The polyacetal fiber according to [1], wherein the inorganic filler comprises at least one of magnesium and silicon.

[3] The polyacetal fibers according to [1] or [2], wherein the inorganic filler is talc.

[4] The polyacetal fibers according to any one of the above [1] to [3], which are multifilament.

[5] The polyacetal fiber according to [4] above, which is a multifilament having a thickness of 36 to 400 denier.

[6] The polyacetal fiber according to [4] or [5], which is a multifilament composed of 12 to 48 monofilaments.

[7] The polyacetal fibers according to any one of the above [4] to [6], which are multifilaments comprising monofilaments having a thickness of 1 to 12 deniers.

[8] The polyacetal fibers according to any one of the above [1] to [7], which are used for woven fabrics, knitted fabrics or nonwoven fabrics.

[9] A material for stretching, characterized in that:

contains 0.05 to 1.3 parts by mass of an inorganic filler per 100 parts by mass of a polyacetal resin,

the inorganic filler has a primary average particle diameter of more than 0.5 μm and not more than 10 μm,

the melt flow index is 15-45 g/10 min.

[10] A method for producing a polyacetal fiber, characterized in that:

a polyacetal fiber is produced from a polyacetal resin composition by a melt spinning method,

the polyacetal resin composition contains 0.05 to 1.3 parts by mass of an inorganic filler per 100 parts by mass of a polyacetal resin, the inorganic filler having a primary average particle diameter of more than 0.5 μm and not more than 10 μm, and the polyacetal resin composition having a melt flow index of 15 to 45g/10 min.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention can provide a polyacetal fiber having excellent spinning stability and uniform appearance.

Drawings

Fig. 1 is a photograph illustrating an example of polyacetal fiber corresponding to evaluations 1,4, and 6 when evaluating the appearance unevenness in the examples and comparative examples.

Fig. 2 is a schematic view illustrating an example of a spinning machine for polyacetal fibers.

Detailed Description

< polyacetal fiber >

One embodiment of the present invention relates to a polyacetal fiber containing a polyacetal resin and an inorganic filler. The polyacetal fibers of the present invention can suppress the occurrence of "broken filaments" such as breakage of filaments (mainly monofilaments in the case of multifilaments) at the time of winding during spinning, and can also suppress the occurrence of "uneven appearance" by having uniform appearance. Thus, the yarn had excellent spinning stability and uniform appearance.

(polyacetal resin)

Polyacetal resins are also referred to as oxymethylene polymers, and include homopolymers and copolymers. In the present specification, the terms "polyacetal resin" and "oxymethylene polymer" are used simply to refer to both a homopolymer and a copolymer, and are referred to as "oxymethylene homopolymer" and "oxymethylene copolymer" respectively.

The polyacetal resin has an oxymethylene unit (-OCH)₂-). In the case of the oxymethylene copolymer, the copolymer has, in addition to the oxymethylene units, oxyalkylene units represented by the following formula (1).

(in the formula, R₀And R₀' may be the same or different and represents a hydrogen atom, an alkyl group, a phenyl group or an oxyalkylene group. m is an integer of 2 to 6. )

R₀、R₀The alkyl group of the formula (I) is a linear or branched alkyl group having 1 to 20 carbon atoms, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a decyl group, a dodecyl group, and an octadecyl group. Preferably a linear or branched alkyl group having 1 to 4 carbon atoms.

R₀、R₀The alkyl groups indicated for' may be unsubstituted or substituted. Examples of the substituent include a hydroxyl group, an amino group, an alkoxy group, an alkenyloxymethyl group, a halogen group and the like. Examples of the substituted alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. Examples of the alkenyloxymethyl group as a substituent include an allyloxymethyl group and the like. In the present specification, halogen means an element belonging to group 17 of the periodic table, and specific examples thereof include fluorine, chlorine, bromine, iodine, and astatine.

R₀、R₀The phenyl group of' may be unsubstituted or substituted. Examples of the substituent include an alkyl group, an aralkyl group, and a halogen. Examples of the alkyl group as a substituent include a linear or branched alkyl group having 1 to 20 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a decyl group, a dodecyl group, and an octadecyl group. Preferably a linear or branched alkyl group having 1 to 4 carbon atoms. Examples of the aralkyl group as a substituent include a phenyl group, a naphthyl group, and an anthryl group.

R₀、R₀The oxyalkylene group represented by the' is an alkyl group interrupted by 1 or more ether bonds, and a group represented by the following formula (2) is preferably exemplified.

－CH₂－O－(R₁－O)_p－R₂ (2)

(in the formula, R₁Represents an alkylene group. p represents an integer of 0 to 20. R₂Represents a hydrogen atom, an alkyl group, a phenyl group or a glycidyl group. Each (R)₁The units-O) may be identical or different. )

R₁The alkylene group is a linear or branched alkylene group having 2 to 20 carbon atoms, and examples thereof include ethylene, propylene, butylene, and 2-ethylethyleneHexyl and the like, preferably ethylene or propylene. R₁The alkylene groups shown may be unsubstituted or substituted. Examples of the substituent include a hydroxyl group, an amino group, an alkoxy group, an alkenyloxymethyl group, a halogen group and the like. Examples of the substituted alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. Examples of the alkenyloxymethyl group as a substituent include an allyloxymethyl group and the like.

As R₂The alkyl group is a linear or branched alkyl group having 1 to 20 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a decyl group, a dodecyl group, and an octadecyl group. Preferably a linear or branched alkyl group having 1 to 4 carbon atoms. R₂The alkyl groups shown may be unsubstituted or substituted. Examples of the substituent include a hydroxyl group, an amino group, an alkoxy group, an alkenyloxymethyl group, a halogen group and the like. Examples of the substituted alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. Examples of the alkenyloxymethyl group as a substituent include an allyloxymethyl group and the like.

R₂The phenyl groups shown may be unsubstituted or substituted. Examples of the substituent include an alkyl group, an aralkyl group, and a halogen. Examples of the alkyl group as a substituent include a linear or branched alkyl group having 1 to 20 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a decyl group, a dodecyl group, and an octadecyl group. Preferably a linear or branched alkyl group having 1 to 4 carbon atoms. Examples of the aralkyl group as a substituent include a phenyl group, a naphthyl group, and an anthryl group.

R₀And R₀' may be the same, and is preferably a hydrogen atom.

Examples of the oxyalkylene unit represented by the above formula (1) include an oxyethylene unit, an oxypropylene unit, an oxybutylene unit, an oxypentylene unit, and an oxyhexylene unit. Preferably an oxyethylene unit, an oxypropylene unit or an oxybutylene unit, more preferably an oxyethylene unit.

When the polyacetal resin is an oxymethylene copolymer, it may further have a unit represented by the following formula (3).

－CH(CH₃)－CHR₃－ (3)

(in the formula, R₃Is a group represented by the following formula (4). )

－O－(R₁－O)_p－R₄ (4)

(in the formula, R₄Represents a hydrogen atom, an alkyl group, an alkenyl group, a phenyl group or a phenylalkyl group. R₁And p is as defined in formula (2). )

R₄The alkyl group is a linear or branched alkyl group having 1 to 20 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a decyl group, a dodecyl group, and an octadecyl group. Preferably a linear or branched alkyl group having 1 to 4 carbon atoms.

R₄The alkyl groups shown may be unsubstituted or substituted. Examples of the substituent include a hydroxyl group, an amino group, an alkoxy group, an alkenyloxymethyl group, a halogen group and the like. Examples of the substituted alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. Examples of the alkenyloxymethyl group as a substituent include an allyloxymethyl group and the like.

R₄The alkenyl group is a straight-chain or branched alkenyl group having 2 to 20 carbon atoms, and examples thereof include a vinyl group, an allyl group, and a 3-butenyl group. R₄The alkenyl groups shown may be unsubstituted or substituted. Examples of the substituent include a hydroxyl group, an amino group, an alkoxy group, an alkenyloxymethyl group, a halogen group and the like. Examples of the substituted alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. Examples of the alkenyloxymethyl group as a substituent include an allyloxymethyl group and the like.

R₄The phenyl groups shown may be unsubstituted or substituted. Examples of the substituent include an alkyl group, an aralkyl group, and a halogen. Examples of the alkyl group as the substituent include a linear or branched alkyl group having 1 to 20 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, and a decyl groupDodecyl and octadecyl, and the like. Preferably a linear or branched alkyl group having 1 to 4 carbon atoms. Examples of the aralkyl group as a substituent include a phenyl group, a naphthyl group, and an anthryl group.

R₄Examples of the alkyl moiety and the phenyl moiety in the phenylalkyl group include the above-mentioned R₄Illustrative of the alkyl and phenyl groups shown. Examples of the phenylalkyl group include a benzyl group, a phenylethyl group, a phenylbutyl group, a 2-methoxybenzyl group, a 4-methoxybenzyl group, and a 4- (allyloxymethyl) benzyl group.

When the polyacetal resin is an oxymethylene copolymer, it is preferable that the repeating unit represented by the above formula (1) or (3) is contained in an amount of 0.5 to 7.5 mol%.

When a crosslinked structure is present in the polyacetal resin, the glycidyl group in the group represented by the above formula (2), the structure derived from an olefin in the alkenyloxymethyl group as a substituent, or the alkenyl group in the group represented by the above formula (4) can serve as a crosslinking point for further polymerization reaction, thereby forming a crosslinked structure.

(inorganic Filler)

The polyacetal fibers of the present invention may contain an inorganic filler.

The material of the inorganic filler is not particularly limited, and for example, glass fiber, talc, mica, calcium carbonate, potassium carbonate whisker, pigment, boron nitride, and the like can be used. The inorganic filler containing at least one of magnesium and silicon (silicon) is preferable, talc or mica is more preferable, and talc is particularly preferable.

The inorganic filler has a primary average particle diameter of more than 0.5 μm and not more than 10 μm. If the inorganic filler having a primary average particle diameter within this range is used, the occurrence of filament breakage and appearance unevenness can be suppressed. Within this numerical range, the smaller the primary average particle diameter, the more excellent the effect of suppressing filament breakage and the effect of suppressing appearance unevenness tend to be. Therefore, the primary average particle diameter is preferably 0.6 to 9.0. mu.m, particularly preferably 0.7 to 8.0. mu.m. More preferably 0.7 μm or more and less than 4.8 μm, most preferably 0.7 to 1.2 μm.

The primary average particle diameter is a 50% volume average particle diameter of a particle size distribution measured by a laser diffraction method, as shown in examples described later.

The polyacetal fiber of the present invention contains an inorganic filler in an amount of 0.05 to 1.3 parts by mass per 100 parts by mass of the polyacetal resin. If the amount of the inorganic filler is too small or too large, the filaments are likely to be broken and the appearance tends to be uneven. In addition, there is a tendency for the fiber strength to be impaired. The content of the inorganic filler is preferably 0.06 to 1.0 part by mass, more preferably 0.07 to 0.8 part by mass, particularly preferably 0.07 to 0.5 part by mass. Most preferably 0.07 to 0.3 parts by mass.

(other Components)

The polyacetal fibers of the present invention may contain known components blended in the polyacetal resin composition during production, in addition to the polyacetal resin and the inorganic filler. The known components are described in detail later.

The melt flow index of the polyacetal fiber of the present invention is 15 to 45g/10min, preferably 18 to 42g/10min, and particularly preferably 20 to 40g/10min, from the viewpoint of good take-up of the fiber at the time of spinning. When the value of the melt flow index is too small, filaments which are not solidified in the drawing step up to the melt spinning may be scattered, and the appearance may be uneven. If the value of the melt flow index is too large, yarn breakage frequently occurs in the drawing step, and there is a fear that sufficient drawing cannot be performed. As a result, when the value of the melt flow index is too small or too large, filament breakage and appearance unevenness are likely to occur.

The melt flow index can be measured by a method according to ISO 1133 using, for example, a melt indexer manufactured by Toyo Seiki Seisaku-Sho K.K. The measurement conditions were 190 ℃ and the load was 2.16 kg.

The polyacetal fibers of the present invention may be monofilaments, or may be multifilaments formed by bundling a plurality of filaments, and preferably are multifilaments.

The thickness of the multifilament may be determined as appropriate depending on the application, etc., and is preferably 36 to 400 deniers, more preferably 40 to 350 deniers.

The number of monofilaments constituting the multifilament may be appropriately determined depending on the application, and is preferably 12 to 48, more preferably 20 to 40.

The thickness of the monofilament constituting the multifilament may be appropriately determined depending on the application, and is preferably 1 to 12 deniers, and more preferably 3 to 10 deniers.

The polyacetal fibers of the present invention can be applied to various uses including woven fabrics, knitted fabrics, nonwoven fabrics, ropes, and paper sheets. Suitably it can be used in a woven, knitted or non-woven fabric.

< method for producing polyacetal fiber >

The polyacetal fiber of the present invention can be produced by any method, and the inorganic filler having a primary average particle diameter within the above numerical range (more than 0.5 μm and 10 μm or less, preferably 0.6 to 9.0 μm, more preferably 0.7 to 8.0 μm, particularly preferably 0.7 μm or more and less than 4.8 μm, most preferably 0.7 to 1.2 μm) is preferably contained in the above amount (0.05 to 1.3 parts by mass, preferably 0.06 to 1.0 part by mass, more preferably 0.07 to 0.8 part by mass, particularly preferably 0.07 to 0.5 part by mass, most preferably 0.07 to 0.3 part by mass per 100 parts by mass of the polyacetal resin), and a polyacetal resin composition having a melt flow index in the above-mentioned numerical range (15 to 45g/10min, preferably 18 to 42g/10min, particularly preferably 20 to 40g/10min) is prepared, and the polyacetal resin composition is subjected to a melt spinning method to produce the polyacetal resin composition.

(production of polyacetal resin composition)

The method for producing the polyacetal resin composition is not particularly limited, and examples thereof include the following methods: a polyacetal resin is obtained by carrying out a polymerization reaction using a cyclic oligomer and a polymerization catalyst, and an inorganic filler is added to the obtained polyacetal resin. When the polyacetal resin is an oxymethylene copolymer, a comonomer is also used in the polymerization reaction.

As the cyclic oligomer, a cyclic oligomer of formaldehyde such as trioxane which is a cyclic trimer of formaldehyde, and tetraoxane which is a cyclic tetramer is used, and trioxane is preferable. Trioxane may contain water, formic acid, methanol, and formaldehyde as impurities inevitably produced during industrial production, and trioxane containing these impurities may be used.

When the polyacetal resin is an oxymethylene copolymer, the comonomer is not particularly limitedBy definition, cyclic ethers or cyclic formals having at least 1 carbon-carbon bond are preferred. Examples of the cyclic ether or cyclic formal having at least 1 carbon-carbon bond include 1, 3-dioxane, 2-ethyl-1, 3-dioxane, 2-propyl-1, 3-dioxane, 2-butyl-1, 3-dioxane, 2-dimethyl-1, 3-dioxane, 2-phenyl-2-methyl-1, 3-dioxane, 4-methyl-1, 3-dioxane, 2, 4-dimethyl-1, 3-dioxane, 2-ethyl-4-methyl-1, 3-dioxane, 4-dimethyl-1, 3-dioxane, 4, 5-dimethyl-1, 3-dioxane, 2, 4-trimethyl-1, 3-dioxane, 4-hydroxymethyl-1, 3-dioxane, 4-butyloxymethyl-1, 3-dioxane, 4-phenoxymethyl-1, 3-dioxane, 4-chloromethyl-1, 3-dioxane, 1, 3-dioxybicyclo [3,4, 0]]Nonane, ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, styrene oxide, oxetane, 3-bis (chloromethyl) oxetane, tetrahydrofuran, and oxetanes such as 1, 3-dioxepane and 1,3, 5-trioxepane, and oxetanes such as 1,3, 6-trioxocane, and oxetane. From these comonomers, R is formed₀And R₀' the oxyalkylene unit represented by the formula (1) which is likewise a hydrogen atom. As the cyclic ether or cyclic formal having at least 1 carbon-carbon bond, an oxyalkylene group having 2 carbon atoms (-OCH) is preferable₂CH₂-) and particularly preferably 1, 3-dioxane.

In the present invention, R₀And R₀' not simultaneously hydrogen atom (R)₀And R₀' one or both of which are other than hydrogen atoms) can be formed by copolymerizing a glycidyl ether compound and/or an epoxy compound, for example.

The glycidyl ether and the epoxy compound are not particularly limited, and epichlorohydrin; alkyl glycidyl formals such as methyl glycidyl formal, ethyl glycidyl formal, propyl glycidyl formal and butyl glycidyl formal; diglycidyl ethers such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, hexamethylene glycol diglycidyl ether, resorcinol diglycidyl ether, bisphenol a diglycidyl ether, hydroquinone diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and polybutylene glycol diglycidyl ether; triglycidyl ethers such as glycerol triglycidyl ether and trimethylolpropane triglycidyl ether; tetraglycidyl ethers such as pentaerythritol tetraglycidyl ether.

In the present invention, the oxymethylene copolymer may be a 2-membered copolymer or a multi-membered copolymer, and as the oxymethylene copolymer, in addition to the oxymethylene copolymer having an oxymethylene unit and an oxyalkylene unit represented by the above formula (1), an oxymethylene copolymer containing an oxymethylene unit, an oxyalkylene unit represented by the above formula (1), and a unit represented by the above formula (3), and the like can be widely used. The oxymethylene copolymer may have a crosslinked structure. In the present invention, the unit represented by the formula (3) can be formed by copolymerizing an allyl ether compound, for example.

Examples of the allyl ether compound include polyethylene glycol allyl ether, methoxypolyethylene glycol allyl ether, polyethylene glycol-polypropylene glycol allyl ether, butoxypolyethylene glycol-polypropylene glycol allyl ether, polypropylene glycol diallyl ether, phenylethyl allyl ether, phenylbutyl allyl ether, 4-methoxybenzyl allyl ether, 2-methoxybenzyl allyl ether, and 1, 4-diallyloxymethylbenzene.

The amount of the comonomer is suitably determined depending on the kind of the comonomer, the physical properties of the oxymethylene copolymer as the object, and the like, and is preferably 0.1 to 20 parts by mass, particularly preferably 1 to 15 parts by mass, based on 100 parts by mass of the cyclic oligomer as the main monomer.

When the polyacetal resin is an oxymethylene copolymer, the oxymethylene copolymer preferably has oxymethylene units and oxyethylene units (which are contained in the oxyalkylene units represented by the above formula (1)), and the content of the oxyethylene units is preferably 0.5 to 7.5 mol, more preferably 0.5 to 7.0 mol, still more preferably 1.0 to 4.0 mol, particularly preferably 1.0 to 2.5 mol, based on 100 mol of the oxymethylene units. The content of the oxymethylene unit and the oxyethylene unit in the oxymethylene copolymer can be determined by a Nuclear Magnetic Resonance (NMR) method.

As the polymerization catalyst used in the production of the polyacetal resin, any polymerization catalyst can be used. For example, a cationic polymerization catalyst such as a boron trifluoride compound, a fluorinated aralkyl boron compound, perchloric acid, or a heteropoly acid can be used. The polymerization catalyst may be used alone in 1 kind, or may be used in combination of 2 or more kinds. The amount of the polymerization catalyst to be used may be determined as appropriate. The catalysts may be fed into the reaction system separately or may be mixed in advance as a polymerization catalyst mixture to be supplied to the polymerization reaction.

In the production of a polyacetal resin, a chain transfer agent (also referred to as a molecular weight modifier or a viscosity modifier) for adjusting the degree of polymerization can be used. The type of the chain transfer agent is not particularly limited, and examples thereof include carboxylic acids, carboxylic anhydrides, esters, amides, imides, phenols, acetal compounds, and the like, and particularly phenol, 2, 6-dimethylphenol, methylal, polyacetal dimethoxide, methoxymethylal, dimethoxymethylal, trimethoxymethylal, and oxymethylene di-n-butyl ether can be suitably used. Among them, methylal is most preferable. The chain transfer agent can be diluted in an inert solvent in the polymerization reaction as necessary.

The content of the chain transfer agent may be determined as appropriate depending on MFI and the like. Generally, the amount of the cyclic oligomer is adjusted to 0.5% by mass or less based on the amount of the cyclic oligomer in the polymerization raw material. The lower limit of the amount of addition is not particularly limited as long as it is more than 0% by mass.

The polyacetal resin composition prepared by compounding the above-mentioned raw materials is supplied to the polymerization reaction at an MFI of 15 to 45g/10min, preferably 18 to 42g/10min, more preferably 20 to 40g/10 min. The polymerization reaction is not particularly limited, and can be carried out in the same manner as in the conventionally known method for producing a polyacetal resin. That is, any of bulk polymerization, suspension polymerization, solution polymerization, melt polymerization, and the like can be used, and bulk polymerization is particularly preferred.

The bulk polymerization is a polymerization method using a monomer in a molten state and substantially not using a solvent. In the bulk polymerization, the polymer in the monomer mixture is crystallized with the progress of the polymerization, and finally the whole system is made into a block and a powder to obtain a solid polymer. The polymerization is carried out in the absence of oxygen, preferably in a nitrogen atmosphere using a known polymerization apparatus.

The polymerization catalyst may be added directly to the reaction system, but since the catalyst can be uniformly dispersed in the reaction system, it is preferably added after diluted with an organic solvent which does not adversely affect the polymerization system.

The polymerization temperature is not particularly limited, but is usually 60 to 120 ℃. The pressure during the polymerization reaction is not particularly limited, but is preferably in the range of 99.0 to 101.00kPa as an absolute pressure when the atmospheric pressure is 100 kPa. The time of the polymerization reaction (residence time in the polymerization apparatus) is not particularly limited, but is usually 2 to 30 minutes. When stirring is performed during the polymerization reaction, the rotation speed of the stirring blade is preferably 10 to 100rpm, and particularly preferably 20 to 60 rpm.

After the polymerization reaction has sufficiently proceeded, a known terminator may be mixed into the reaction system as necessary to deactivate the polymerization catalyst and the polymerization growth end, thereby stopping the polymerization reaction. This step is referred to as a termination step. As known terminators, trivalent organic phosphorus compounds such as triphenylphosphine; hydroxides of alkali metals; hydroxides of alkaline earth metals; amine compounds such as diethylamine, triethylamine, tributylamine, triethanolamine, N-methyldiethanolamine, N-diethylhydroxylamine, N-isopropylhydroxylamine, N-dioctadecylhydroxylamine, and N, N-dibenzylhydroxylamine.

The amount of the terminator to be added is not particularly limited as long as it is an amount sufficient to deactivate the catalyst, and the molar ratio to the catalyst is usually 1.0X 10^－1～1.0×10¹The range of (1) is used.

The terminator may be used in the form of a solution or suspension.

The temperature at the time of adding and mixing the terminator is not particularly limited, but is preferably 0 to 160 ℃ and particularly preferably 0 to 120 ℃. The pressure is not particularly limited, and is preferably in the range of 99.0 to 101.0kPa in absolute pressure when the atmospheric pressure is 100 kPa. The time for mixing after the addition (residence time in the mixer) is not particularly limited, but is preferably 1 to 150 minutes, and particularly preferably 1 to 120 minutes.

The crude polyacetal resin is obtained by the polymerization reaction and the termination step which is appropriately carried out. The crude polyacetal resin is in a state before unreacted raw materials and the like are removed.

The polymerization reaction proceeds sufficiently, and after the polymerization termination step, which is performed if necessary, is completed to obtain a crude polyacetal resin, the crude polyacetal resin discharged from the polymerization machine is pulverized by a stirring mill or the like, the pulverized crude polyacetal resin is blended with a known stabilizer, and the blend is heated, melted and kneaded by a single-screw or twin-screw extruder, a twin-screw paddle type continuous mixer, or the like. This step is referred to as a stabilization step.

Blending may be carried out by a known method, and for example, melt kneading may be carried out by using a mixer connected in series to a polymerization machine. The apparatus for melt kneading preferably has a ventilation function, and examples of such an apparatus include a single-screw or multi-screw continuous extruder kneader having at least 1 ventilation hole, a twin-screw surface-renewal type horizontal kneader, and the like. These devices may be used alone or in combination of 2 or more. When a twin-screw extruder is used, the crude polymer and the stabilizer may be supplied to the twin-screw extruder through separate lines and blended in the twin-screw extruder.

As the known stabilizer, for example, an antioxidant such as ethylenebis (oxyethylene) bis [ 3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate; heat stabilizers such as melamine; a formaldehyde scavenger; acid scavengers, and the like. Further, for example, additives such as nucleating agents, plasticizers, delustering agents, foaming agents, lubricants, mold release agents, antistatic agents, ultraviolet absorbers, light stabilizers, deodorizing agents, flame retardants, slip agents, perfumes, and antibacterial agents may be added.

Further, a transesterification catalyst, various monomers, a coupling agent (for example, a polyfunctional cyanate ester compound and the like), a terminal treating agent, another resin, wood flour, a natural organic filler such as starch and the like may be added.

The temperature for melt kneading is not particularly limited as long as it is not lower than the melting point of the product obtained by the polymerization reaction, and is preferably in the range of 170 ℃ to 270 ℃ and more preferably 190 ℃ to 250 ℃.

The pressure at the time of melt kneading is not particularly limited, and in order to remove the cyclic oligomer of the unreacted raw material, the formaldehyde component derived from the cyclic oligomer, the formaldehyde derived from the hemiacetal terminal, and the like, it is preferable to carry out the melt kneading under reduced pressure together with a degassing treatment. When the above apparatus is used, the degassing under reduced pressure is carried out through the above vent hole. Therefore, the pressure for melt kneading is preferably in the range of 10 to 100kPa, more preferably 10 to 70kPa, and particularly preferably 10 to 50kPa on an absolute pressure gauge, assuming that the atmospheric pressure is 100 kPa. The rotation speed of the stirring blade during melt kneading is preferably 50 to 200rpm in the twin-screw extruder. The preferred speed of the twin-screw surface renewal type horizontal kneader is 1 to 100 rpm.

The time for carrying out the melt kneading (residence time in the melt kneading apparatus) is not particularly limited, but is preferably 1 to 60 minutes, and particularly preferably 1 to 40 minutes.

The composition after the stabilization step is pulverized as necessary, and the inorganic filler having the above-mentioned primary average particle diameter is blended in an amount such that the inorganic filler content of the finally obtained polyacetal fiber becomes the above-mentioned value, and melt-kneaded. The blending method and conditions, and the melt-kneading method and conditions are the same as those in the stabilization step.

The above-mentioned process for producing the polyacetal resin composition is an example, and the addition and omission of the process may be appropriately performed, or the contents of the respective processes may be changed. For example, the inorganic filler may be blended with a known stabilizer and melt-kneaded not after the stabilization step but in the stabilization step. Further, before stabilization after the termination of the polymerization reaction, washing of the crude polymer, separation and recovery of unreacted monomers, drying, and the like may be carried out as necessary. When purification is required, washing, separation and recovery of unreacted monomers, drying, and the like may be performed after stabilization. The above-mentioned materials may be used in a step different from the above-mentioned step within a range not to impair the object of the present invention, and for example, an antioxidant or a heat stabilizer may be used in the polymerization termination step.

(spinning)

The polyacetal resin composition was subjected to a known melt spinning method to produce a polyacetal fiber. One embodiment of the spinning method will be described with reference to fig. 2.

Polyacetal fibers are produced by drawing a plurality of fibrous materials (filaments) discharged from a discharge port of a spinning machine into fibers by a drawing roll, and further drawing the fibers by a pre-drawing roll and a drawing roll. If necessary, the drawn fiber may be wound up by a take-up roller after the drawing step. The drawing step and the stretching step are preferably continuous steps. In addition, the method for producing polyacetal fiber of the present invention can use not only the method of spinning multifilament as shown in fig. 2, but also the method of spinning monofilament.

The configuration of the spinning machine used in the production method of the present invention is not particularly limited, and the polyacetal resin composition may be molten as long as the polyacetal fibers can be discharged from the discharge port. The polyacetal resin composition may be melt-kneaded in a spinning machine having an extruder as required. Examples of the spinning machine include a common melt spinning device for multifilament or monofilament formed by a single screw extruder, a gear pump, a screen, and a die. The barrel temperature of the extruder, the gear pump temperature, the number of holes of the discharge nozzle, and the like can be appropriately adjusted as necessary. The fineness (fiber thickness) of the drawn fiber can be appropriately adjusted by the feed amount of the raw material and the speed of the take-up roll.

The filament discharged from the discharge port of the spinning machine was first drawn as a polyacetal fiber by a drawing roll and then sent to a pre-drawing roll, and thereafter drawn using 1 or more drawing rolls. By drawing, the tensile strength of the fiber can be improved. In the present specification, the "pre-drawing roll" refers to a roll positioned between a drawing roll and a take-up roll, and usually the fiber is not drawn between the pre-drawing roll and the take-up roll, or sometimes drawn to a slight extent in order to ensure spinning stability. The "stretching roll" refers to a roll disposed after the roll before stretching, and the fiber is stretched between the roll before stretching and the stretching roll and/or between a plurality of stretching rolls. In the method for producing polyacetal fibers of the present invention, at least 1 drawing roll, preferably at least 2 drawing rolls may be used. The use of 2 or more stretching rollers is preferable because the polyacetal fibers can be stretched in a plurality of stages.

The drawing speed (m/min) of the drawing roll and the take-up speed (m/min) of the take-up roll are appropriately determined depending on the composition of the fiber and the conditions of the spinning apparatus and the like. The take-up speed of the take-up roll may be substantially the same as the rotational speed of the stretching roll, and the take-up speed may be slightly slower by 0.1 to 10%, preferably 0.3 to 5%, more preferably 0.5 to 2% than the rotational speed of the stretching roll in consideration of the shrinkage of the polyacetal fiber.

The stretching ratio in the stretching step is preferably 1.0 to 10.0 times. In the present specification, the "draw ratio" is a value indicating how much the fiber before drawing is drawn in the drawing step, and can be calculated by dividing the rotation speed of the drawing roll by the rotation speed of the roll before drawing.

In the stretching step, stretching can be performed in multiple stages using a pre-stretching roll and 2 or more stretching rolls. By drawing in multiple stages, spinning stability and secondary processability can be improved. The stretching can be more suitably performed in 2 stages using a pre-stretching roll and 2 or more stretching rolls in the stretching step.

The stretching step may be suitably performed using a pre-stretching roll and 2 or more stretching rolls, and is configured such that: in the drawing step, the polyacetal fiber passes through the pre-drawing roller and then passes through 2 or more drawing rollers, and the temperature of at least 1 roller of the 2 or more drawing rollers is 3 to 20 ℃ higher than that of the pre-drawing roller, more preferably 5 to 20 ℃ higher. In the above configuration, the temperature of the pre-drawing roller and the drawing roller is adjusted to improve the spinning stability. Further preferably, in the stretching step, the temperature of the pre-stretching roll and the temperature of at least 1 roll of 2 or more stretching rolls are set to 130 to 155 ℃. By adjusting the temperatures of the pre-drawing roll and the drawing roll as described above, a polyacetal fiber having good spinning properties can be obtained.

< Material for stretching >

As described above in the present specification, when a polyacetal resin composition containing a specific amount of an inorganic filler having a specific particle diameter and having a melt flow index adjusted to a specific range is used, the drawing can be performed uniformly at the time of spinning, and the characteristics thereof are not limited to fibers, and can be said to be suitable for other molded articles requiring a drawing step at the time of production. Accordingly, according to one embodiment of the present invention, there is provided a material for drawing which contains 0.05 to 1.3 parts by mass of an inorganic filler having a primary average particle diameter of more than 0.5 μm and not more than 10 μm per 100 parts by mass of a polyacetal resin and has a melt flow index of 15 to 45g/10 min. The drawing material of the present invention has the features described in the section of polyacetal fiber in the present specification.

Examples

The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the following examples.

The measurement and evaluation of the physical properties of the examples and comparative examples in the present specification were carried out by the following methods.

< primary average particle diameter >

The inorganic filler used in each of examples and comparative examples was scooped up to about 3 to 4 spoons with a small stainless steel spatula, and the scooped up spoons were collected together with 5ml of water in a glass bottle and then tightly closed to obtain a sample. The resulting sample was stirred and then the particle size distribution was measured by laser diffraction. The 50% volume average particle diameter obtained from the obtained particle size distribution was taken as the primary average particle diameter.

< melt flow index >

The melt flow index (hereinafter referred to as MFI) of the polyacetal (B) used in each of the examples and comparative examples was measured using a melt index meter (manufactured by Toyo Seiki Seisaku-Sho Ltd.). The measurement was carried out in accordance with ISO 1133 at a temperature of 190 ℃ under a load of 2.16 kg.

< filament breakage frequency >

When the fiber is to be wound, the fiber is apparently stopped at the winding portion by continuously irradiating a strobe light having the same frequency as the number of winding rotations. At this time, if filament breakage (filament breakage) occurs, fuzz occurs on the surface of the take-up roll. The fuzz was counted visually. The evaluation criteria are as follows.

1) No filament breakage occurred 1 time within 10 minutes.

2) Only 1 filament breakage was confirmed within 10 minutes.

3) Only 1 filament breakage was confirmed within 3 minutes.

4) Filament breakage was observed 1 to 2 times within 1 minute.

5) Filament breakage was observed 3 to 6 times within 1 minute.

6) Filament breakage was observed 7 to 9 times in 1 minute.

7) More than 10 filament breaks were observed within 1 minute.

8) No fiber is obtained.

< uneven appearance >

If the polyacetal fiber can be properly stretched, the appearance becomes uniform and transparent, and when the polyacetal fiber is not uniformly stretched due to some external factors, the portion becomes whitish and opaque. Therefore, a certain range of the fiber bobbins obtained in each of examples and comparative examples was observed, and the frequency of occurrence of the opaque portion was visually counted. The evaluation criteria are as follows.

1) All can be seen transparent.

2) Only 1 white opaque portion appears in the range of 15cm x 15cm of the bobbin.

3) Only 1 white opaque portion appears in the range of 5cm x 5cm of the bobbin.

4) 2-3 parts of white opaque parts appear in the range of 5cm multiplied by 5cm of the shuttle peg.

5) A white opaque part of 4-6 appears in the range of 5cm multiplied by 5cm of the shuttle peg.

6) A white opaque part where 7-9 is located appears within a range of 5cm multiplied by 5cm of the shuttle peg.

7) More than 10 white opaque parts appear in the range of 5cm × 5cm of the bobbin.

Fig. 1 illustrates an example of evaluations 1,4, and 6 among the above evaluation criteria.

< tensile maximum Strength >

The polyacetal fibers obtained in the examples and comparative examples were subjected to temperature and humidity control at a temperature of 23 ℃ and a humidity of 50% for 24 hours or more. The temperature-and humidity-adjusted fiber was subjected to a tensile test using an all-purpose tester (Autograph) AGS-X1 kN manufactured by shimadzu corporation. The measurement was carried out by drawing a 120mm long fiber at a speed of 100 mm/min.

< example 1 >

(1) Preparation of polyacetals

A polyacetal resin composition (hereinafter, sometimes referred to as polyacetal (B)) which is a raw material of the polyacetal fiber was prepared by the following method.

First, 100 parts by mass of trioxane and 4.0 parts by mass of 1, 3-dioxane as a comonomer were mixed, boron trifluoride diethyl etherate was supplied to the catalyst in an amount of 0.045 mmol per 1 mol of trioxane, and polymerization was carried out in a twin-screw kneader having intermeshing paddles. At this time, methylal was added as a viscosity adjuster in an amount of 0.12 part by mass based on 100 parts by mass of trioxane to adjust the viscosity. After completion of the polymerization, a small amount of a benzene solution of triphenylphosphine was added to deactivate the catalyst, and the mixture was pulverized to obtain a crude polyacetal.

To the obtained crude polyacetal were added and blended an additive (Irganox (registered trademark) 245 (manufactured by BASF Japan) and melamine (manufactured by Mitsui chemical Co., Ltd.), the resulting blend was introduced into a co-rotating twin-screw extruder (manufactured by Nippon Steel Co., Ltd., inner diameter 69mm, L/D: 31.5) at 60 kg/hr, the crude polyacetal was melted at 220 ℃ under a reduced pressure of 20kPa in a vent part, and continuously introduced into a twin-screw surface-renewal type horizontal kneader (actual effective internal volume 60L: volume obtained by subtracting the volume occupied by the stirring blade from the total internal volume). the liquid level was adjusted so that the twin-screw surface renewal type horizontal kneader would stay for 25 minutes, and the polyacetal (a) was obtained as an intermediate raw material by taking out the polyacetal continuously by a gear pump while carrying out devolatilization under reduced pressure of 20kPa at 220 ℃.

Talc (trade name: Mistron Vapor, manufactured by Imerys Specialities Japan, Ltd.) having a primary average particle size of 4.8 μm was added in an amount of 0.07 part by mass per 100 parts by mass of the polyacetal (A) and blended, and then introduced into a co-rotating twin-screw extruder (manufactured by Japan Steel works, Ltd., inner diameter 58mm, L/D49.0) at 100 kg/hr and thoroughly mixed and pelletized to obtain a polyacetal (B) as a raw material.

The MFI of the polyacetal (B) was 27g/10 min.

(2) Spinning

The obtained polyacetal (B) was fed to a spinning machine (manufactured by Uni-Plus) having an extruder with a cylinder set temperature of 190 ℃, a gear pump and a discharge nozzle, and spun. The discharge amount was 1kg/h, the number of holes of the discharge nozzle was 36 holes, the drawing speed was 100m/min, the drawing roll speed was 500m/min, the take-up speed was 500m/min, and the temperature of the drawing roll was 150 ℃. At this time, the draw ratio was 5 times.

(3) Spinning stability and physical properties of the resulting fiber

A polyacetal fiber having a single fiber (monofilament) thickness of 8 deniers, consisting of 36 monofilaments and a multifilament fiber thickness of 300 deniers was obtained. The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

It was confirmed that the frequency of filament breakage during spinning was only 1 time in 1 minute. As the appearance unevenness, 2 white opaque portions appeared in the range of 5cm × 5cm of the obtained fiber bobbin. The tensile maximum strength was 8.3N.

< example 2 >

A polyacetal fiber was obtained in the same manner as in example 1, except that the loading of talc was changed to 0.15 part by mass per 100 parts by mass of the polyacetal (A). The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

< example 3 >

A polyacetal fiber was obtained in the same manner as in example 1, except that the loading of talc was changed to 0.25 parts by mass per 100 parts by mass of the polyacetal (A). The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

< example 4 >

A polyacetal fiber was obtained in the same manner as in example 2, except that talc (trade name: SG-2000, manufactured by Nippon talc Co., Ltd.) having an average primary particle diameter of 1.2 μm was used. The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

< example 5 >

A polyacetal fiber was obtained in the same manner as in example 2, except that talc (trade name: D-600, manufactured by Nippon talc Co., Ltd.) having an average primary particle diameter of 0.7 μm was used. The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

< example 6 >

A polyacetal fiber was obtained in the same manner as in example 1, except that mica (manufactured by Katakura & Co-op Agri, Inc.: ミクロマイカ MK-100) having an average primary particle diameter of 5.4 μm was used in place of talc and 0.08 part by mass was added to 100 parts by mass of the polyacetal (A). The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

< example 7 >

A polyacetal fiber was obtained in the same manner as in example 2, except that the MFI of the polyacetal (B) was adjusted to 20g/10 min. The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

< example 8 >

A polyacetal fiber was obtained in the same manner as in example 2, except that the MFI of the polyacetal (B) was adjusted to 40g/10 min. The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

< comparative example 1 >

Polyacetal fibers were obtained in the same manner as in example 1, except that the inorganic filler was not used. The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

< comparative example 2 >

A polyacetal fiber was obtained in the same manner as in example 1, except that the loading of talc was changed to 2.00 parts by mass per 100 parts by mass of the polyacetal (A). The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

< comparative example 3 >

A polyacetal fiber was obtained in the same manner as in example 1, except that 5.00 parts by mass of a red pigment having an average primary particle diameter of 14 μm was added instead of talc per 100 parts by mass of the polyacetal (A). The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

< comparative example 4 >

A polyacetal fiber was obtained in the same manner as in example 2, except that the MFI of the polyacetal (B) was adjusted to 8g/10 min. The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

< comparative example 5 >

A polyacetal fiber was obtained in the same manner as in example 2, except that the MFI of the polyacetal (B) was adjusted to 50g/10 min. The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

< comparative example 6 >

A polyacetal fiber was obtained in the same manner as in example 6, except that 2.00 parts by mass of mica was blended per 100 parts by mass of the polyacetal (a). The characteristics of the polyacetal fibers thus obtained were measured, and the results are shown in Table 1.

[ Table 1]