JP2022162532A - Biodegradable polyester resin, and method for producing the same - Google Patents

Abstract

To provide a biodegradable polyester resin which has improved degradability under the natural environment.SOLUTION: A biodegradable polyester resin is composed of a dicarboxylic acid component and a diol component. In the total acid components, 35 mol% or more of an aliphatic dicarboxylic acid component is contained, and 1 ppm or more of a sulfur component is contained. The biodegradable polyester resin preferably contains 20 mol% or more of an aliphatic diol component in the total diol components. The aliphatic diol component is preferably ethylene glycol and/or 1,4-butanediol.SELECTED DRAWING: Figure 1

Description

The present invention relates to a biodegradable polyester resin and a method for producing the same.

Polyester resins are widely used in various fields because of their light weight, ease of processing, and availability at low cost.
Polyester resins are hardly decomposed in the natural environment, and semi-permanently remain in the ground even after burial treatment. As a result, the discarded polyester products pose problems such as spoiling the scenery and destroying the living environment of marine organisms. In order to solve these problems, polyester resin recycling systems such as a separate waste collection system, a returnable system, and a deposit system are being introduced.

As resins that can solve environmental problems, so-called biodegradable polyester resins, which are decomposed by the enzymes of naturally occurring microorganisms, are known. Examples of biodegradable polyester resins include polylactic acid, polyethylene succinate, polybutylene succinate, and the like, and these are used in a wide range of applications such as packaging containers, tableware, stationery, garbage bags, and miscellaneous goods. .

For example, Patent Document 1 discloses a molded article made of a biodegradable resin that essentially contains polylactic acid and also contains polybutylene succinate adipate or polybutylene adipate terephthalate.

JP-A-2005-350530

In recent years, society's awareness of the need to protect the natural environment has increased. For example, there is a demand for a biodegradable polyester resin that is even more excellent in degradability in the natural environment in order to suppress the adverse effects of microplastics on marine organisms caused by the disposal of plastic products into the ocean.

The present invention has been made in view of this background, and an object of the present invention is to provide a biodegradable polyester resin with improved degradability in the natural environment.

The present inventors arrived at the present invention as a result of intensive studies in order to solve the above problems.
That is, the gist of the present invention is as follows (1) to (9).
(1) A biodegradable polyester resin comprising a dicarboxylic acid component and a diol component, containing 35 mol% or more of an aliphatic dicarboxylic acid component and 1 ppm or more of a sulfur component in the total acid component. .
(2) The biodegradable polyester resin of (1), which contains 20 mol % or more of the aliphatic diol component in all the diol components.
(3) The biodegradable polyester resin of (1) or (2), wherein the aliphatic diol component is ethylene glycol and/or 1,4-butanediol.
(4) The biodegradable polyester resin according to any one of (1) to (3), wherein the upper limit of the sulfur component content is 500 ppm or less.
(5) The biodegradable polyester resin according to any one of (1) to (4), which does not contain catalyst-derived metal components.
(6) The biodegradable polyester resin according to any one of (1) to (5), which retains an intrinsic viscosity of 60% or less after being treated in water at a temperature of 60° C. for 7 days.
(7) The biodegradable polyester according to any one of (1) to (6), which retains a number average molecular weight of 70% or less after being treated for 7 days in an environment of a temperature of 60°C and a humidity of 85% RH. resin.
(8) In a marine biodegradability test (ASTM D6691), under conditions of seawater temperature of 30 ° C ± 2 ° C, biodegradation after 80 days is 60% or more, any of (1) to (7) biodegradable polyester resin.
(9) A method for producing a biodegradable polyester resin according to any one of (1) to (8), wherein an organic sulfonic acid compound is used as a polymerization catalyst.
(10) A fiber composed of the biodegradable polyester resin according to any one of (1) to (8).

When the biodegradable polyester resin of the present invention contains a specific amount of sulfur component, in addition to biodegradability, wet heat decomposability is improved and hydrolysis is facilitated. As a result, biodegradation and hydrolysis by microorganisms proceed, so that the degradability in the natural environment is even more excellent.

1 shows an example of a schematic cross-section of a split type composite form composed of the biodegradable polyester resin of the present invention. 1 shows another example of a schematic cross-section of a split type composite form composed of the biodegradable polyester resin of the present invention.

The present invention will be described in detail below.
The biodegradable polyester resin of the present invention is composed of a dicarboxylic acid component and a diol component.
Among all the acid components constituting the polyester resin, the content of the aliphatic dicarboxylic acid component is 35 mol% or more, preferably 50 mol% or more, more preferably 70 mol% or more, and 90 mol% It is more preferably 100 mol % or more, and particularly preferably 100 mol %. If it is less than 35 mol %, the crystallinity becomes too high, and the wet heat degradability and biodegradability are lowered.

Examples of aliphatic dicarboxylic acid components include oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, pimelic acid, suberic acid, azelaic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid phthalic acid and the like.

Among them, oxalic acid, succinic acid, glutaric acid, adipic acid, or sebacic acid is preferable, and succinic acid, adipic acid, and sebacic acid are more preferable, since they are easily available as plant-derived raw materials and are more biodegradable. Acid and adipic acid are more preferred.

An acid component other than the aliphatic dicarboxylic acid component may be contained within a range that does not impair the effects of the present invention. Examples of such acid components include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 5-(alkali metal)sulfoisophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, Alternatively, ester-forming derivatives thereof, unsaturated aliphatic dicarboxylic acids exemplified by fumaric acid, maleic acid, itaconic acid, etc., or ester-forming derivatives thereof may be mentioned.

Among all the diol components constituting the biodegradable polyester resin of the present invention, the aliphatic diol component is preferably contained in an amount of 20 mol% or more, more preferably 30 mol% or more, and more preferably 50 mol% or more. More preferably, it is contained in an amount of 80 mol % or more, and particularly preferably in an amount of 100 mol %. If the content of the aliphatic diol component in the total diol component is less than 20 mol %, the crystallinity may become too high, and the wet heat degradability and biodegradability may be lowered.

Examples of aliphatic diol components include ethylene glycol, 1,4-butanediol, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,4-butylene glycol, 1, 5-pentanediol, 1,6-hexanediol and the like.
Among them, ethylene glycol and 1,4-butanediol are preferable because they are readily available as plant-derived raw materials and have excellent biodegradability.

Examples of diol components other than the aliphatic diol component include polyalkylene glycols such as polyethylene glycol, triethylene glycol and polytetramethylene glycol, hydroquinone, 4,4′-dihydroxybisphenol, 1,4-bis(β-hydroxy ethoxy)benzene, bisphenol A, 2,5-naphthalenediol, and aromatic diols such as glycols obtained by adding ethylene oxide to these diols.

The biodegradable polyester resin of the present invention may contain a component having a trifunctional or higher ester-forming group. Components having a trifunctional or higher ester-forming group include trifunctional or higher polyhydric alcohols; trifunctional or higher polycarboxylic acids or their anhydrides, acid chlorides and esters; and trifunctional or higher hydroxycarboxylic acids or Anhydrides, acid chlorides, and esters thereof.

Tri- or higher functional polyhydric alcohols include, for example, glycerin, trimethylolpropane, pentaerythritol and the like. These may be used individually by 1 type, and may use 2 or more types.

Trifunctional or higher polyvalent carboxylic acids or anhydrides thereof include, for example, trimesic acid, propanetricarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, cyclopentatetracarboxylic anhydride and the like. mentioned. These may be used individually by 1 type, and may use 2 or more types.

Tri- or higher functional hydroxycarboxylic acids include, for example, malic acid, hydroxyglutaric acid, hydroxymethylglutaric acid, tartaric acid, citric acid, hydroxyisophthalic acid, and hydroxyterephthalic acid. These may be used individually by 1 type, and may use 2 or more types.

The content of the component having a trifunctional or higher ester-forming group is preferably 0.01 mol % to 2.0 mol % of the total acid components constituting the biodegradable polyester resin of the present invention. If it exceeds 2.0 mol%, the crosslinking of the polymer may proceed excessively, causing problems such as the inability to stably pull out strands, deterioration of moldability, and deterioration of various physical properties. , may be undesirable.

The biodegradable polyester resin of the present invention contains 1 ppm or more of sulfur components. By containing a sulfur component of 1 ppm or more, the polyester resin of the present invention is improved in wet heat decomposability in addition to biodegradability by microorganisms, and is easily hydrolyzed. As a result, biodegradation and hydrolysis by microorganisms proceed, and the degradability in the natural environment becomes even more excellent. The sulfur component content is preferably 1 to 500 ppm, more preferably 5 to 300 ppm, even more preferably 10 to 200 ppm, and particularly preferably 15 to 150 ppm. If it exceeds 500 ppm, the resin may have a low degree of polymerization, and the molecular weight may not sufficiently increase, resulting in poor moldability and strength. In addition, excessive hydrolysis may result in a significant decrease in strength when formed into a molded article or fiber, which may not be practical.
The sulfur component is preferably derived from an organic sulfonic acid-based compound used as a polymerization catalyst in the production method described below.

The biodegradable polyester resin of the present invention may use a metal catalyst together with an organic sulfonic acid compound as a polymerization catalyst, but is preferably obtained without using a metal catalyst. That is, the biodegradable polyester resin of the present invention preferably does not contain metal components derived from the catalyst. Examples of metal-based catalysts include compounds such as germanium, antimony, titanium, zinc, aluminum, iron, magnesium, potassium, calcium, sodium, manganese, nickel, and cobalt.

The biodegradable polyester resin of the present invention may contain ether bond-containing diols such as diethylene glycol and triethylene glycol. This increases the hydrophilicity of the resin and further improves the biodegradability.
The content of the ether bond-containing diol is preferably 20 mol % or less, more preferably 1 to 15 mol %, of the total diol component.

The biodegradable polyester resin of the present invention may contain an antioxidant. Although the content of the antioxidant is not particularly limited, it is, for example, 0.1 to 1.0% by mass in the biodegradable polyester resin.

Antioxidants include, for example, hindered phenol-based antioxidants.
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] Although undecane and the like are used, tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane is preferred from the viewpoint of effect and cost.

The biodegradable polyester resin of the present invention may contain an anti-coloring agent. Examples of coloring inhibitors include phosphorous acid, phosphoric acid, polyphosphoric acid, trimethyl phosphite, triethyl phosphite, triphenyl phosphite, tridecyl phosphite, trimethyl phosphate, tridecyl phosphate, triphenyl phosphate, and the like. of phosphorus compounds. These phosphorus compounds may be used alone or in combination of two or more.

The biodegradable polyester resin of the present invention may contain a crystal nucleating agent. Crystal nucleating agents include carbon black, calcium carbonate, synthetic silicic acid and silicates, zinc oxide, high-site clay, kaolin, basic magnesium carbonate, mica, talc, quartz powder, diatomaceous earth, dolomite powder, and titanium oxide. , zinc oxide, barium sulfate, calcium sulfate, alumina, calcium silicate, boron nitride, etc., low-molecular-weight organic compounds having a metal salt of a carboxyl group, such as octylic acid, toluic acid, heptanoic acid, pelargonic acid, lauric acid, myristic Metal salts such as acid, palmitic acid, stearic acid, behenic acid, cerotic acid, montanic acid, melissic acid, benzoic acid, p-tert-butylbenzoic acid, terephthalic acid, terephthalic acid monomethyl ester, isophthalic acid, isophthalic acid monomethyl ester etc.

The content of the crystal nucleating agent is preferably 0.1 to 5 parts by mass, more preferably 1 to 2 parts by mass, per 100 parts by mass of the biodegradable polyester resin. If it is less than 0.1 parts by mass, it may be difficult to obtain the desired effects, and if it exceeds 5 parts by mass, the effects may saturate, which may be uneconomical and undesirable.

The limiting viscosity of the biodegradable polyester resin of the present invention is preferably 1.0 to 2.0 from the viewpoint of excellent moldability into containers, fibers, films, etc., and excellent strength when molded.

The biodegradable polyester resin of the present invention is excellent in wet heat decomposability. As an index of wet heat decomposability, the intrinsic viscosity retention rate after treatment in water at a temperature of 60 ° C. for 7 days is preferably 60% or less, more preferably 50% or less, and 40% or less. is more preferred. The details of the method for calculating the retention rate of the intrinsic viscosity will be described later in Examples.

The number average molecular weight of the biodegradable polyester resin of the present invention is preferably 20,000 or more, more preferably 40,000 or more, even more preferably 60,000 or more. If the number-average molecular weight is less than 40,000, molding into containers, fibers, films, etc. may be difficult, or the strength of molded articles may be insufficient.

As another index of wet heat degradability, the biodegradable polyester resin of the present invention has a number average molecular weight retention rate of 70% or less when treated for 7 days in an environment with a temperature of 60 ° C. and a humidity of 85% RH. It is preferably 60% or less, more preferably 30% or less. The lower limit of the retention rate is preferably 5%, more preferably 10%, and even more preferably 14%. If it is less than 5%, hydrolysis may proceed excessively, resulting in reduced strength when formed into molded articles, fibers, or the like. The details of the method for calculating the retention rate of the number average molecular weight will be described later in Examples.

The biodegradable polyester resin of the present invention preferably has a biodegradability index of 60% or more (ASTM D6691) in a marine biodegradability test, more preferably 70% or more, as a biodegradability index. More preferably, it is 75% or more. The degree of biodegradation is measured after 80 days at a seawater temperature of 30°C ± 2°C, and the details of the calculation method will be described later in Examples.

The biodegradable polyester resin of the present invention preferably has a glass transition temperature of -50 to 30°C. Also, the crystal melting point is preferably 80 to 140°C.

An example of the method for producing the biodegradable polyester resin of the present invention is described below.
For example, the acid component and the diol component as described above are used as raw materials, and are subjected to an esterification or transesterification reaction at a temperature of 200 to 260° C. by a conventional method. It can be obtained by conducting a polycondensation reaction at a temperature of up to 280°C, preferably 240 to 280°C.

The molar ratio (G/A) between the glycol component (G) and the dicarboxylic acid component (A) in the polyester resin raw material is preferably 1.00 to 2.00, more preferably 1.05 to 1.50. When it is less than 1.00, the esterification or transesterification reaction does not proceed sufficiently, and the polycondensation reaction may be difficult to proceed. On the other hand, if it exceeds 2.00, the polycondensation reaction may take a long time.

Furthermore, depending on the purpose and application, an acid component or a diol component may be added to the polymer obtained by the polycondensation reaction, and the depolymerization reaction may be carried out at a temperature of 240 to 280°C.

An organic sulfonic acid compound is used as a polymerization catalyst. Thereby, the biodegradable polyester resin to be obtained can be made to contain a sulfur component in an amount within a specific range.
The amount of the organic sulfonic acid compound added is 0.1×10 ⁻⁴ mol or more with respect to 1 mol of the acid component constituting the biodegradable polyester resin in order to make it easier to set the content of the sulfur component within a specific range. is preferred, and 1×10 ⁻⁴ to 20×10 ⁻⁴ mol is more preferred.
If the amount of the organic sulfonic acid-based compound added is less than 1×10 ⁻⁴ mol, the sulfur component in the obtained polyester resin may be too small. On the other hand, if it exceeds 20×10 ⁻⁴ mol, the sulfur component in the obtained polyester resin increases, and hydrolysis and thermal decomposition during polymerization are accelerated, resulting in a decrease in polymerizability and a sufficient increase in molecular weight. or the resin itself may not 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 etc. 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, Preferred are m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, p-toluenesulfonic acid, methyl p-toluenesulfonate, 5-sulfoisophthalic acid and salts thereof.

In the production method of the present invention, by using an organic sulfonic acid compound as a polymerization catalyst, the polyester resin can be made to contain a sulfur component in a specific amount, and as a result, the polyester resin can exhibit biodegradability. be able to. If an organic sulfonic acid-based compound is not used and only another polymerization catalyst (e.g., a metal-based catalyst) is used, the content of the sulfur component cannot be set to a specific range, and the polyester resin has excellent biodegradability. can't get

The biodegradable polyester resin of the present invention has excellent degradability under natural environment. Its uses are not particularly limited, but examples thereof include moldings, fibers, sheets, films, adhesives, resin solutions and the like.

Molded articles, sheets, films, and fibers using the biodegradable polyester resin of the present invention are packaging materials for packaging liquids, powders, and solids such as various foods, medicines, and miscellaneous goods, and agricultural materials. , construction materials, etc., and is particularly suitable for disposable applications. Specifically, injection molded products (e.g. fresh food trays, fast food containers, coffee capsule containers, cutlery, outdoor leisure products, etc.), extrusion molded products (e.g. fishing lines, fishing nets, vegetation nets, secondary processing water retention sheets, etc.), hollow molded products (bottles, etc.), agricultural mulch films, tunnel films, house films, sunshades, weed control sheets, ridge sheets, germination sheets, forestry fumigation sheets, flat yarns, etc. Including binding tapes, parts such as back sheets and top sheets of sanitary products such as diapers, packaging sheets, shopping bags, shopping bags, garbage bags, draining bags, compost bags, etc., ropes, binding materials, surgical thread for medical use, It can be used for sutures, tapes with creases, face masks, wet towels, wet wipes, and the like, and can be particularly suitably used for disposable applications.

The form of fibers composed of the biodegradable polyester resin of the present invention includes long fibers (continuous fibers) and short fibers, and the long fibers may be monofilaments or multifilaments. Staple fibers and short-cut fibers may be used as short fibers. In addition, a split yarn is exemplified as a fiber form other than the above.

In the case of a long fiber (continuous fiber) as the fiber form, it can be obtained by melt spinning, winding, and roller drawing using the biodegradable polyester resin of the present invention by the FDY method or the POY method. In addition, by the spunbond method, the biodegradable polyester resin of the present invention is melt-spun, and a large number of spun fibers are deposited and collected on a net or the like to obtain a long fiber web, which is heat embossed. A nonwoven fabric can be obtained by integrating the long fibers by treatment, needle punching, or the like.

When short fibers are used as the form of fibers, the biodegradable polyester resin of the present invention is melt-spun, and then the bundled yarn bundle is hot-stretched at an appropriate magnification and then cut to a desired length. to obtain short fibers.

When the short fibers are staple fibers, the fiber length is preferably about 20 to 150 mm, and the fibers are mechanically crimped. Such staple fibers are used for dry nonwoven fabrics (for example, thermal through nonwoven fabrics, spunlaced nonwoven fabrics, needle punched nonwoven fabrics, airlaid nonwoven fabrics, nonwoven fabrics thermally bonded after being entangled by needle punching or spunlace, etc.) and for spun yarns. can be applied as In addition, dry nonwoven fabrics made of staple fibers can be suitably applied to various members such as hygiene products, diapers, and incontinence pads. In obtaining a spun yarn or a dry-laid nonwoven fabric, fibers other than the fibers made of the biodegradable polyester resin of the present invention may be appropriately mixed.

When the short fibers are short-cut fibers, the fiber length is about 2 to 20 mm, and can be applied to wet-laid nonwoven fabrics and synthetic papers. It is preferable that the short-cut fibers are not crimped and are provided with an oil or the like to be water-dispersible. A wet-laid nonwoven fabric or the like composed of short-cut fibers can be suitably applied to applications such as filters. In obtaining a wet-laid nonwoven fabric or the like, fibers other than the fibers made of the biodegradable polyester resin of the present invention may be appropriately mixed.

The characteristic values of the fiber composed of the biodegradable polyester resin of the present invention include, for example, a single fiber fineness of 0.5 to 25.0 decitex, a strength of 0.1 to 6.0 cN/dtex, and an elongation of 20 to 200%. One with a range is included. The above physical properties may be adjusted by changing the conditions in the spinning process and the drawing process depending on the application of the fiber.

As the cross-sectional form of the fiber, a single-phase fiber having only the biodegradable polyester resin of the present invention as a constituent resin, or a biodegradable polyester resin of the present invention having different constituents and having at least two resins. A single-phase fiber obtained by blending, a composite fiber composed of a plurality of resins that are the biodegradable polyester resin of the present invention and have different constituents, and a biodegradable polyester resin of the present invention and other resins. Composite form fibers composed of
Moreover, it may be a modified cross-section fiber having a cross section other than circular, or a hollow cross-section fiber having a hollow portion.
Among the biodegradable polyester resins of the present invention, single-phase fibers that are made of a biodegradable polyester resin with a relatively low melting point (e.g., 180° C. or lower) can be used as full-melt type thermal binder fibers. can be used.

Fibers having a composite cross section include a side-by-side composite, a core-sheath composite, a sea-island composite, and a split composite.
When making a composite form, the biodegradable polyester resin of the present invention is a combination of resins having different constituent components, the combination of the biodegradable polyester resin of the present invention and other biodegradable resins, and the biodegradability of the present invention Combinations of polyester resins and other non-biodegradable resins can be mentioned. These combinations may be appropriately selected according to the required characteristics, the intended use, and the like. Considering the characteristics of the biodegradable polyester resin of the present invention, it is also preferable to select a biodegradable resin such as polylactic acid when combining it with other resins.

As a core-sheath type composite form, the biodegradable polyester resin of the present invention with a high melting point is arranged in the core component, and the biodegradable polyester resin of the present invention with a low melting point is arranged in the sheath component. , the sheath component can be used as a heat-bonding fiber that functions as a heat-bonding binder component. Moreover, when the polylactic acid resin having a melting point of about 170 to 180° C. is used as the core component, and the biodegradable polyester resin of the present invention having a melting point of 160° C. or less is used as the sheath component, biodegradability is obtained. It can be used as a thermal adhesive fiber.
In addition, the all-melting type thermally bonded fiber and the core-sheath type composite thermally bonded fiber described above are mixed with the main fiber such as a fiber made of a resin with a higher melting point than a binder component with a lower melting point, or a natural fiber. It is preferable to obtain a spun yarn or a nonwoven fabric.

As the split type composite form, the biodegradable polyester resin of the present invention is a combination of resins having different constituent components, the combination of the biodegradable polyester resin of the present invention and other biodegradable resins, and the biodegradation of the present invention. Examples include combinations of biodegradable polyester resins and other non-biodegradable resins. As a split type composite form, in two types of constituent resins, a cross-sectional form in which a region of one resin component is divided by the presence of a region of the other resin component, and the two types of constituent resins are radially arranged. Arranged forms, forms in which two types of constituent resins are laminated in a plurality of stripes, and one resin is arranged in the core, and the other resin is arranged in a large number of leaves around the core. A multi-leaf morphology, etc., can be mentioned.

In such a splittable composite fiber, by combining two types of constituent resins having poor compatibility, by giving a physical impact to the splittable composite fiber, the two constituent resins By peeling and splitting at the interface between them, fine fineness fibers composed only of the constituent resins can be obtained.

1 and 2 show an example of a schematic cross section of a split type composite form. 1 is a four-leaf cross-section and FIG. 2 is a petal-shaped cross-section. In FIG. 1, the core component divides and arranges four leaf portions arranged around the core component. In FIG. 2, the other component is radially arranged in a petal-like form within one component, and the other component is separated by petal-like components.

Even if the biodegradable polyester resin of the present invention is divided into a plurality of pieces by other components and arranged, the other components are divided into a plurality of pieces by the biodegradable polyester resin of the present invention. may Further, the biodegradable polyester resins of the present invention are combined with each other and have poor compatibility, and the biodegradable polyester resin of the present invention is the biodegradable polyester resin of the present invention, and the resin is It may be divided into a plurality of pieces by resins having different constituent components, or may be arranged vice versa.
The segmented composite form may also be flat or have a hollow central portion.

Physical impact means applied to splittable conjugate fibers include physical impact in the process of imparting mechanical crimping in the fiber manufacturing process, and physical impact when creating a web using a blended cotton, carding machine, etc. Physical impact when the obtained web is made into a nonwoven fabric by needle punching or high pressure water jet treatment, high pressure water jet treatment or liquid flow treatment for fabrics such as woven and knitted fabrics and nonwoven fabrics made of the fibers of the present invention. , impact due to airflow treatment, and the like. In particular, the non-woven fabric, in which the fibers are three-dimensionally entangled with each other by needle punching or high-pressure water jet treatment and the fibers are divided to express split fibers, is very dense and has a good texture, so it is good for the skin. It can be suitably used for medical sanitary materials such as face masks and diapers, which are intended to be touched.

EXAMPLES Next, the present invention will be specifically described with reference to examples. Various characteristic values in the examples were measured or evaluated as follows.
(a) Glass transition temperature, crystalline melting point The obtained polyester resin was measured in a nitrogen stream using a differential scanning calorimeter (Diamond DSC) manufactured by Perkin Elmer Co., Ltd. in a temperature range of -70 ° C. to 200 ° C. ( Temperature drop) Measurement was performed at a rate of 20°C/min and a sample amount of 8 mg.

(b) Number Average Molecular Weight Polyester resin was measured for polystyrene-equivalent number average molecular weight under the following conditions using gel permeation chromatography (GPC).
Liquid transfer device: Shimadzu Nexera-i Plus
Detector: Shimadzu differential refractive index detector RID-10A
Column: LF-404 manufactured by SHODEX
Solvent: chloroform Flow rate: 0.3 ml/min Measurement temperature: 40°C

(c) Intrinsic Viscosity A polyester resin was measured at 20° C. in a phenol/tetrachloroethane=1/1 (weight ratio) mixed solvent at a concentration of 0.5% by weight.

(d) Composition of polyester resin The polyester resin is dissolved in deuterated chloroform, ¹ H-NMR is measured with a nuclear magnetic resonance apparatus JNM-ECZ manufactured by JEOL Ltd., and the protons of each component in the chart obtained. The copolymerization amount and content were determined from the integrated intensity of the peak of .

(e) Sulfur component and metal component content A polyester resin is melt-molded at 300 ° C. to form a disc-shaped molded plate with a diameter of 3 cm and a thickness of 1 cm. Quantitative analysis was performed by the calibration curve method to determine the content.

(f) Retention rate of number average molecular weight after treatment at 60° C.×85% RH×7 days A polyester resin was powdered with an average particle diameter of 200 μm or less, and 50 mg of the powder was used as a sample. Using a constant temperature and humidity bath manufactured by Shimadzu Corporation, the product was treated for 7 days under conditions of an internal temperature of 60° C. and an internal humidity of 85%. The number-average molecular weight of the treated sample was measured in the same manner as in (b) above, and the number-average molecular weight retention was calculated according to the following formula.
Retention rate (%) = (number average molecular weight of sample after test x 100) / (number average molecular weight of sample before test)

(g) Intrinsic Viscosity Retention after Treatment in Water at 60° C. for 7 Days 4 g of polyester resin was placed in a metal container containing 200 mL of water, sealed, heated to 60° C., and treated for 7 days. The intrinsic viscosity of the treated sample was measured in the same manner as in (c) above, and the retention of the number average molecular weight was calculated according to the following formula.
Retention rate (%) = (intrinsic viscosity of sample after test x 100) / (intrinsic viscosity of sample before test)

(h) Marine biodegradability test (ASTM D6691)
A powder of a polyester resin having an average particle size of 200 μm or less was used as a sample. According to ASTM D6691, the amount of CO ₂ generated 80 days after the start of the test was measured, and the degree of biodegradation was calculated in the marine biodegradability test. The test was conducted using seawater at a measurement temperature of 30±2°C.
Evaluation was made according to the following criteria.
◎: Biodegradability is 75% or more ○: Biodegradability is 70% or more and less than 75% △: Biodegradability is 60% or more and less than 70% ×: Biodegradability is less than 60%

Example 1
81.9 parts by mass of succinic acid and 56.0 parts by mass of ethylene glycol were supplied to an esterification reactor and reacted under conditions of a temperature of 200° C. and a pressure of 50 hPa for 2 hours to obtain an oligomer (esterified product).
The above oligomer was transferred to a polymerization reactor, 0.05 parts by mass of 5-sulfosalicylic acid as a polymerization catalyst organic sulfonic acid compound and 0.0868 parts by mass of polyphosphoric acid as a phosphorus compound were added, and the reactor was evacuated. After 60 minutes, the final pressure was adjusted to 0.9 hPa and melt polycondensation reaction was carried out at a temperature of 280° C. for 5 hours to obtain a biodegradable polyester resin.

Examples 2-21, Comparative Examples 1-2
Acid component, diol component, component having a trifunctional or higher ester-forming group, charged amount of crystal nucleating agent, organic sulfonic acid compound as a polymerization catalyst, added amount of metal catalyst, reaction temperature of melt polycondensation reaction, A polyester resin was obtained in the same manner as in Example 1, except that the reaction time was changed as shown in Table 1.

Comparative Examples 3-6
Example 1 except that no organic sulfonic acid-based compound was added as a polymerization catalyst, a metal-based catalyst was used in the amount shown in Table 1, and the charged amounts of the acid component and the diol component were changed as shown in Table 1. A polyester resin was obtained in the same manner,

表１、表２中の略語は、下記のものを示す。
ＳＵ：コハク酸
ＡＤＡ：アジピン酸
ＳＥＡ：セバシン酸
ＴＰＡ：テレフタル酸
ＥＧ：エチレングリコール
ＢＤ：ブタンジオール
ＢＡＥＯ：ビスフェノールＡのエチレンオキサイド付加物
ＤＥＧ：ジエチレングリコール
ＴＥＧ：トリエチレングリコール
ＳＳ：５－スルホサリチル酸
ＧｅＯ_２：二酸化ゲルマニウム
ＴＢＴ：テトラブチルチタネート
Ｓｂ_２Ｏ_３：三酸化アンチモン

Abbreviations in Tables 1 and 2 indicate the following.
SU: succinic acid ADA: adipic acid SEA: sebacic acid TPA: terephthalic acid EG: ethylene glycol BD: butanediol BAEO: ethylene oxide adduct of bisphenol A DEG: diethylene glycol TEG: triethylene glycol SS: 5-sulfosalicylic acid GeO ₂ : Germanium dioxide TBT: Tetrabutyl titanate Sb ₂ O ₃ : Antimony trioxide

Table 2 shows the resin composition and sulfur component content of the polyester resins obtained in Examples 1 to 21 and Comparative Examples 1 to 6.

Table 3 shows the evaluation results of the polyester resins obtained in Examples 1-21 and Comparative Examples 1-6.

As is clear from Table 3, the biodegradable polyester resins of the present invention obtained in Examples 1 to 21 were excellent in wet heat degradability and biodegradability.

As can be understood from Examples 8 to 10, the biodegradable polyester resin of the present invention was excellent in wet heat degradability and biodegradability even when an organic sulfonic acid catalyst and a metal catalyst were used in combination. .

On the other hand, the polyester resin obtained in Comparative Example 1 contained a small amount of the organic sulfonic acid-based compound as a polymerization catalyst, so the content of the sulfur component was too small, and the wet heat decomposability and biodegradability were poor. rice field.

Since the polyester resin obtained in Comparative Example 2 contained a small amount of the aliphatic dicarboxylic acid component, the crystallinity was high, and the wet heat degradability and biodegradability were poor.

The polyester resins obtained in Comparative Examples 3 to 6 were inferior in wet heat decomposability and biodegradability because only metal-based catalysts were used as polymerization catalysts.

Next, an example in which a fiber was produced using the polyester resin of the example obtained above will be described. The physical properties of fibers were measured by the following methods.
(1) According to JIS L1015 8.5.1 A method, except that the fiber fineness measurement sample is cut to a length of 20 mm, 100 fibers are taken out, the mass is measured, and the number of measurements is 4 times. measured by
(2) Fiber strength and elongation Measured according to JIS L-1015 8.7.

Example 22 (short fiber)
Using the biodegradable polyester resin obtained in Example 4, melt spinning was performed using a spinneret with a hole number of 1040 and a hole diameter of 0.22 mm under conditions of a discharge rate of 440 g/min, a spinning temperature of 240°C, and a spinning speed of 700 m/min. gone. Next, the obtained undrawn yarn was converged to form a tow of 50 ktex and drawn under the conditions of a drawing temperature of 65° C. and a drawing ratio of 3.1 times. Next, after applying mechanical crimping with a push-type crimper and applying a finishing oil, the fibers were cut to a fiber length of 51 mm, and single-phase staple fibers having a fineness of 2.4 dtex, a strength of 2.5 cN/dtex, and an elongation of 52% were obtained. got

Example 23 (core-sheath type composite staple fiber)
Poly DL-lactic acid (PLA6202D manufactured by NW Co., Ltd.) mainly composed of L-lactic acid with an L-lactic acid/D-lactic acid (copolymerization molar ratio) of 98.7/1.3 was placed in the core. A spinneret with 1014 holes and a hole diameter of 0.35 mm was used so that the obtained biodegradable polyester resin was placed in the sheath, and the discharge rate was 428 g/min. Melt spinning was performed at a speed of 700 m/min. Next, the obtained undrawn yarn was converged to form a tow of 50 ktex, and drawn under the conditions of a drawing temperature of 75° C. and a draw ratio of 3.0 times. Next, mechanical crimping is applied with a push-type crimper, a finishing oil is applied, and the fibers are cut into fibers of 51 mm in length, and have a fineness of 2.4 dtex, a strength of 2.5 cN/dtex, and an elongation of 49%. got

Example 24 (splittable conjugate staple fiber)
Poly DL-lactic acid (PLA6202D manufactured by NW Co., Ltd.) mainly composed of L-lactic acid with an L-lactic acid/D-lactic acid (copolymerization molar ratio) of 98.7/1.3 and the biodegradable polyester resin of Example 4 using a 4-lobed cross section composite spinneret (1014 holes) in which the cross section of the fiber is a 4-lobed composite cross section (the number of divisions is 5 (total of both components)) as shown in FIG. is placed in the leaf portion, and the biodegradable polyester resin of Example 4 is placed in the core portion, and the composite ratio is set to core/leaf = 35/65 as a melt volume ratio, spinning temperature is 230 ° C., discharge rate is 485 g / min. was melt-spun at a spinning speed of 800 m/min to obtain an undrawn splittable conjugate fiber.
Next, the obtained undrawn yarn was drawn at a drawing temperature of 65° C. and a draw ratio of 2.90 times, then mechanically crimped with a push-type crimper, and after applying a finishing oil, it was cut into fibers of 51 mm in length and fineness. A split type conjugate short fiber having a strength of 2.2 dtex, a strength of 2.9 cN/dtex and an elongation of 41% was obtained.

Example 25 (Splittable conjugate staple fiber)
Poly DL-lactic acid (PLA6202D manufactured by NW Co., Ltd.) mainly composed of L-lactic acid with an L-lactic acid/D-lactic acid (copolymerization molar ratio) of 98.7/1.3 and the biodegradable polyester resin of Example 4 Using a petal-shaped cross-section composite spinneret (850 holes) with a cross section of the fiber having a split number of 20 (total of both components) as shown in FIG. The biodegradable polyester resin of Example 4 was arranged in a region other than the petal shape, and the composite ratio was 50/50 as a melt volume ratio, the spinning temperature was 230°C, the discharge rate was 550 g/min, and the spinning speed was 860 m/min. to obtain an undrawn splittable conjugate fiber.
Next, the obtained undrawn yarn was drawn at a drawing temperature of 60° C. and a drawing ratio of 2.50 times, then mechanically crimped with a push-type crimper, and after applying a finishing oil, it was cut into fibers of 51 mm in length and fineness. A split type conjugate short fiber having a strength of 3.3 dtex, a strength of 2.2 cN/dtex and an elongation of 55% was obtained.

Claims (10)

A polyester resin comprising a dicarboxylic acid component and a diol component,
Containing 35 mol% or more of an aliphatic dicarboxylic acid component in all acid components,
A biodegradable polyester resin containing 1 ppm or more of a sulfur component. 2. The biodegradable polyester resin according to claim 1, containing 20 mol % or more of the aliphatic diol component in all diol components. 3. The biodegradable polyester resin according to claim 1, wherein the aliphatic diol component is ethylene glycol and/or 1,4-butanediol. The biodegradable polyester resin according to any one of claims 1 to 3, wherein the upper limit of the sulfur component content is 500 ppm or less. The biodegradable polyester resin according to any one of claims 1 to 4, which does not contain a catalyst-derived metal component. 6. The biodegradable polyester resin according to any one of claims 1 to 5, wherein the intrinsic viscosity retention rate after treatment in water at a temperature of 60°C for 7 days is 60% or less. The biodegradable polyester resin according to any one of claims 1 to 6, wherein the retention rate of the number average molecular weight after treatment for 7 days in an environment of temperature 60°C and humidity 85% RH is 70% or less. . The biodegradability according to any one of claims 1 to 7, which has a biodegradability of 60% or more after 80 days in a marine biodegradability test (ASTM D6691) at a seawater temperature of 30°C ± 2°C. Biodegradable polyester resin. A method for producing a biodegradable polyester resin according to any one of claims 1 to 8, wherein an organic sulfonic acid compound is used as a polymerization catalyst. A fiber comprising the biodegradable polyester resin according to any one of claims 1 to 8.

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