JP4821202B2 - Method for producing biodegradable spunbond nonwoven fabric - Google Patents

Description

  The present invention relates to an aliphatic polyester biodegradable nonwoven fabric excellent in hydrolysis resistance and having a good color tone, and has a favorable production environment without the generation of irritating odors when producing the nonwoven fabric, The present invention relates to a biodegradable nonwoven fabric that can be suitably used for various uses including civil engineering materials.

  In recent years, non-woven fabrics made of various biodegradable resins have been proposed due to increasing environmental awareness. Biodegradable nonwoven fabric is chemically decomposed by the action of sunlight, ultraviolet rays, heat, water, enzymes, microorganisms, etc. in natural environments, and further disintegrates morphologically. It can be disposed of by leaving it outdoors. Even if incinerated, the biodegradable resin generally has a lower calorific value than polyester, polypropylene, nylon, and other resins used in conventional nonwoven fabrics, so it does not damage the incinerator during incineration. There is.

  In addition, among biodegradable resins, plant resources that take in carbon dioxide from the atmosphere and grow can be used as raw materials, and it can be expected that global warming can be suppressed by the circulation of carbon dioxide, and the problem of resource depletion can be solved. Because of this possibility, attention has been focused on resins starting from plant resources, that is, resins using biomass.

  However, conventional biodegradable resins using biomass have not been used as general-purpose plastics because they have problems such as low mechanical properties and heat resistance and high production costs. On the other hand, in recent years, polylactic acid resin using lactic acid obtained by starch fermentation as a raw material has attracted attention as a biodegradable resin having relatively high mechanical properties and heat resistance and low production cost.

  Development of polylactic acid nonwoven fabric using polylactic acid resin is preceded by civil engineering materials and agricultural materials that make use of biodegradability, followed by life materials, industrial materials, vehicle materials, and building materials. Application to applications is also expected.

  However, polylactic acid fibers and non-woven fabrics composed thereof are subject to hydrolysis under the environment of use, so that there is a problem that the product life is short in applications where high strength retention is required.

  In order to improve this problem, the mechanical properties of the non-woven fabric are improved by using a polylactic acid-based sheath fiber made of a polylactic acid-based sheath-core composite fiber and having a melting point of 20 ° C. or more lower than that of the core component polylactic acid-based resin. In addition, a biodegradable coating material for agricultural use made of a polylactic acid-based long-fiber nonwoven fabric is known in which the strength retention after irradiation for 300 hours is 50% or more in a weather resistance test using a weather meter (See Patent Document 1). However, since the biodegradable coating material for agriculture does not take any measures against hydrolysis, which is a major factor in the process of reducing the strength of polylactic acid fiber, hydrolysis reaction occurs under the influence of rain dew during use. Further, there has been a drawback that the strength of the fiber, and thus the nonwoven fabric, is reduced.

  Thus, a polylactic acid fiber that has been improved in hydrolysis resistance by adding a monocarbodiimide compound has been proposed (see Patent Document 2). However, the monocarbodiimide compound is expensive and has a problem that it is difficult to make a high concentration master by bleed out.

  On the other hand, as a relatively inexpensive carbodiimide compound, a biodegradable plastic composition having a hydrolysis resistance improved by adding a polycarbodiimide compound is also known (see Patent Document 3). However, polycarbodiimide compounds have low dispersibility in polylactic acid, are prone to gelation, are not sufficient for improving hydrolysis resistance, and have unstable spinnability when applied to fibers and nonwoven fabrics. It was difficult to apply to the production of traditional fibers and nonwoven fabrics.

  Furthermore, a biodegradable plastic composition is known in which an ultraviolet absorber such as a benzotrial compound or a triazine compound is added in addition to a carbodiimide compound (see Patent Document 4). However, although the weather resistance is improved by adding an ultraviolet absorber, the spinning stability is still unstable when applied to fibers and nonwoven fabrics, and an irritating decomposition gas derived from the carbodiimide compound is generated during melt spinning. It is difficult to apply to the production of industrial fibers and non-woven fabrics, such as the generation of working environment and deterioration of the working environment, and the addition of a carbodiimide compound further deteriorates the color tone of the fibers and non-woven fabrics.

Furthermore, a polylactic acid fiber is known in which a specific polycarbodiimide compound having two or more carbodiimide groups in the molecule and whose ends are sealed with carboxylic acid is mixed (see Patent Document 5). However, even in the case of polylactic acid fibers in which a specific polycarbodiimide compound is mixed, it is difficult to suppress irritating decomposition gas generated during melt spinning and to maintain good color tone of the fibers. It could not be used suitably for the production of nonwoven fabrics.
JP 2000-333542 A JP 2001-261797 A Japanese Patent Laid-Open No. 11-80522 JP 2004-155993 A JP 2004-332166 A

  The present invention relates to an aliphatic polyester biodegradable nonwoven fabric excellent in hydrolysis resistance and having a good color tone, and has a favorable production environment without the generation of irritating odors when producing the nonwoven fabric, It aims at providing the biodegradable nonwoven fabric which can be used suitably for each use including civil engineering materials.

（ここで、Ｒ_１〜Ｒ_３のうち、少なくとも１つはグリシジルエーテル若しくはグリシジルエステルであり、残りは水素、炭素原子数１〜１０のアルキル基、水酸基、アリル基等の官能基）
Ｍｗ ：８万〜５０万
Ｍｗ／Ｍｎ：１．４〜４．０
ここで、Ｍｗは重量平均分子量、Ｍｎは数平均分子量である。
The present invention employs the following means in order to solve such problems. That is,
(1) An aliphatic polyester resin having a carboxyl group at the molecular chain terminal, the molecular weight of the aliphatic polyester resin being in the following range, containing at least one compound represented by the general formula [Chemical Formula 1] And a method for producing a biodegradable spunbond nonwoven fabric containing fibers made of an aliphatic polyester resin in which part or all of the carboxyl groups are blocked by the compound, and spinning at a spinning speed of 4100 to 4300 m / min. A method for producing a biodegradable spunbond nonwoven fabric characterized by the above .

(Here, at least one of R _{1 to} R ₃ is a glycidyl ether or a glycidyl ester, and the rest are functional groups such as hydrogen, an alkyl group having 1 to 10 carbon atoms, a hydroxyl group, and an allyl group).
Mw: 80,000 to 500,000
Mw / Mn: 1.4 to 4.0
Here, Mw is a weight average molecular weight, and Mn is a number average molecular weight.

（ここで、Ｒ _１ 〜Ｒ _３ のうち、少なくとも１つはグリシジルエーテル若しくはグリシジルエステルであり、残りは水素、炭素原子数１〜１０のアルキル基、水酸基、アリル基等の官能基）
Ｍｗ ：８万〜５０万
Ｍｗ／Ｍｎ：１．４〜４．０
ここで、Ｍｗは重量平均分子量、Ｍｎは数平均分子量である。
(2) A biodegradable span containing a core-sheath composite fiber comprising an aliphatic polyester resin in which the molecular weight of the aliphatic polyester resin is in the following range, and both the core component and the sheath component have a carboxyl group at the molecular chain end. It is a bond nonwoven fabric, and only the sheath component resin of the core-sheath composite fiber contains at least one compound represented by the general formula [Chemical Formula 1], and a part or all of the carboxyl groups are contained by the compound. A method for producing a biodegradable spunbonded nonwoven fabric , which is a sealed aliphatic polyester resin and the sheath-sheath component ratio of the core-sheath composite fiber is 5 to 70 vol%, and is spun at a spinning speed of 4100 to 4300 m / min. A method for producing a biodegradable spunbonded nonwoven fabric characterized by comprising:

(Here , at least one of R _{1 to} R ₃ is a glycidyl ether or a glycidyl ester, and the rest are functional groups such as hydrogen, an alkyl group having 1 to 10 carbon atoms, a hydroxyl group, and an allyl group).
Mw: 80,000 to 500,000
Mw / Mn: 1.4 to 4.0
Here, Mw is a weight average molecular weight, and Mn is a number average molecular weight.

(3) The manufacturing method of the biodegradable spunbond nonwoven fabric as described in said (1) or (2) whose terminal carboxyl group density | concentration is 0-20 equivalent / ton.
(4) The production of the biodegradable spunbonded nonwoven fabric according to any one of (1) to (3), wherein the content of the compound of [Chemical Formula 1] is 0.02 to 10 wt% with respect to the total amount of the aliphatic polyester resin. Way .
(5) The method for producing a biodegradable spunbonded nonwoven fabric according to any one of (1) to (4), wherein the aliphatic polyester resin is a polylactic acid resin.
( 6 ) A civil engineering material comprising a biodegradable spunbonded nonwoven fabric obtained by the production method according to any one of (1) to ( 5 ).
( 7 ) An agricultural material comprising a biodegradable spunbonded nonwoven fabric obtained by the production method according to any one of (1) to ( 5 ).
( 8 ) A living material comprising a biodegradable spunbonded nonwoven fabric obtained by the production method according to any one of (1) to ( 5 ).
( 9 ) An industrial material comprising a biodegradable spunbonded nonwoven fabric obtained by the production method according to any one of (1) to ( 5 ).
( 10 ) A vehicle material comprising a biodegradable spunbond nonwoven fabric obtained by the production method according to any one of (1) to ( 5 ).
( 11 ) A building material comprising a biodegradable spunbonded nonwoven fabric obtained by the production method according to any one of (1) to ( 5 ).

Mw: 80,000 to 500,000 Mw / Mn: 1.4 to 4.0
Here, Mw is a weight average molecular weight, and Mn is a number average molecular weight.
(7) A civil engineering material comprising the biodegradable nonwoven fabric according to any one of (1) to (6).
(8) An agricultural material comprising the biodegradable nonwoven fabric according to any one of (1) to (6).
(9) A living material comprising the biodegradable nonwoven fabric according to any one of (1) to (6).
(10) An industrial material comprising the biodegradable nonwoven fabric according to any one of (1) to (6).
(11) A vehicle material comprising the biodegradable nonwoven fabric according to any one of (1) to (6).
(12) A building material comprising the biodegradable nonwoven fabric according to any one of (1) to (6).

  According to the present invention, a biodegradable nonwoven fabric having no irritating odor or the like during production, a good production environment, excellent hydrolysis resistance and good color tone can be obtained. The biodegradable nonwoven fabric of the present invention can be suitably used for various uses including civil engineering materials.

  The biodegradable nonwoven fabric of the present invention is biodegradable using fibers made of an aliphatic polyester resin in which a carboxyl group at the end of a molecular chain is partially or entirely blocked with a compound represented by the general formula [Chemical Formula 1]. It is a nonwoven fabric.

  As long as the biodegradable nonwoven fabric of the present invention is suitable for use, the type of the nonwoven fabric is not limited, and the production method is also a spunbond method, a melt blow method, a flash spinning method, a needle punch method, a hydroentanglement method, There is no particular limitation as long as a suitable production method such as an airlaid method, a thermal bond method, a resin bond method, or a wet method is selected.

  In the case of long-fiber non-woven fabric, for example, after extruding the molten polymer from the nozzle and drawing it with a high-speed suction gas, the fibers are collected on a moving conveyor to form a web, which is further continuously bonded and entangled. So-called spunbond method, for example, by spraying a heated high-speed gas fluid on the molten polymer to stretch the molten polymer into ultrafine fibers, and collect it into a sheet It can be produced by the so-called melt blow method.

  In the case of a short fiber nonwoven fabric, it can be manufactured by combining the following steps, for example. Extruding the molten polymer from the nozzle, drawing it with a roller and drawing it, producing a fiber by crimping, crimping with a crimper, producing a short fiber by cutting with a cutter, the obtained short fiber A process for producing a sheet by stacking and forming a sheet by applying heat bonding or entanglement, or dispersing short fibers in water and then separating them from water, scooping, squeezing and drying to form a web Further, it is a process of manufacturing a sheet by integrating by thermal bonding.

  In the biodegradable nonwoven fabric of the present invention, the aliphatic polyester resin used as a raw material for the fibers constituting the biodegradable nonwoven fabric is not limited in any way, but polylactic acid resin, polybutylene succinate resin, polycaprolactone resin Polyethylene succinate resin, polyglycolic acid resin, polyhydroxybutyrate resin and the like are preferably used, and among them, polylactic acid resin is particularly preferably used because of its relatively high mechanical properties and heat resistance and low production cost. A plurality of these resins may be used in combination. As a method for compounding the resin, a method in which a plurality of types of melted resins are mixed, and a method in which two types of resins are formed into a composite fiber form such as a core-sheath type, a side-by-side type, a sea-island type, or a multileaf type is preferable It is. Further, a crystal nucleating agent, a matting agent, a pigment, an antifungal agent, an antibacterial agent, a flame retardant, a lubricant and the like may be added to the biodegradable resin as long as the effects of the present invention are not impaired. As the lubricant, for example, aliphatic bisamides and / or alkyl-substituted aliphatic monoamides are preferably used, and the addition amount is preferably in the range of 0.1 to 5.0 wt%.

  As the polylactic acid resin, poly (D-lactic acid), poly (L-lactic acid), a copolymer of D-lactic acid and L-lactic acid, or a blend thereof is preferable.

  In the biodegradable nonwoven fabric of the present invention, when producing the biodegradable nonwoven fabric with no generation of irritating odors, good production environment, excellent hydrolysis resistance and good color tone, As a decomposition stabilizer, a glycidyl-modified compound having an isocyanuric acid represented by [Chemical Formula 1] as a basic skeleton is added, and the terminal carboxyl group of an aliphatic polyester resin serving as a raw material for fibers constituting a biodegradable nonwoven fabric using the compound It is important that some or all of these are blocked.

(Here, at least one of R _{1 to} R ₃ is a glycidyl ether or a glycidyl ester, and the rest are functional groups such as hydrogen, an alkyl group having 1 to 10 carbon atoms, a hydroxyl group, and an allyl group).
The glycidyl-modified compound having isocyanuric acid as a basic skeleton used as a hydrolysis-resistant stabilizer in the biodegradable nonwoven fabric of the present invention is not particularly limited as long as it is a compound represented by the above [Chemical Formula 1]. Among the above-mentioned [Chemical Formula 1] R ₁ to ₃ , diallyl monoglycidyl isocyanurate (hereinafter abbreviated as DAMGIC) in which any one is a glycidyl group and the remaining two are allyl groups, or R _{1 of the} above [Chemical Formula 1]. 1 to ₃ , monoallyl diglycidyl isocyanurate (hereinafter abbreviated as MADGIC) in which any two are glycidyl groups and the remaining one is an allyl group, or all of R ₁ to _{3 in} the above [Chemical Formula 1] are glycidyl groups. Some tris (2,3-epoxypropyl) isocyanurate (hereinafter abbreviated as TEPIC) is preferably used. The glycidyl-modified compound having an isocyanuric acid represented by [Chemical Formula 1] used as a hydrolysis-resistant stabilizer and having a basic skeleton may be a single type or a mixture of a plurality of types.

  In the biodegradable nonwoven fabric of the present invention, the content of the glycidyl-modified compound having isocyanuric acid represented by the above [Chemical Formula 1] as the basic skeleton is the total amount of the aliphatic polyester resin that is a raw material for the fibers constituting the biodegradable nonwoven fabric. Is preferably 0.02 to 10 wt%, more preferably 0.05 to 8 wt%, and still more preferably 0.1 to 6 wt%. If the content of the compound is less than 0.02 wt%, the desired hydrolysis resistance cannot be obtained, which is not preferable. On the other hand, when the content of the compound exceeds 10 wt%, an excess of the compound or a mixture thereof that does not contribute to the blocking of the carboxyl group end of the aliphatic polyester resin is present, thereby reducing the production stability of the biodegradable nonwoven fabric. It is not preferable because it leads to cost increase.

  In the biodegradable nonwoven fabric of the present invention, as a method of blocking the terminal carboxyl group with the glycidyl-modified compound having the isocyanuric acid represented by the above [Chemical Formula 1] as a basic skeleton, the compound is terminated in the molten state of the aliphatic polyester. Although it can be obtained by reacting in an appropriate amount as a blocking agent, it is preferable to add and react the compound after completion of the polymerization reaction of the polymer from the viewpoint of increasing the degree of polymerization of the aliphatic polyester and suppressing the residual low molecular weight. . The mixing and reaction of the compound and the aliphatic polyester include, for example, a method of adding the compound to the molten aliphatic polyester immediately after the completion of the polycondensation reaction, stirring and reacting, and adding the compound to the aliphatic polyester chip. , A method of kneading and reacting in a reaction can or an extruder after mixing (hereinafter referred to as melt kneading), a method of continuously adding the liquid compound to an aliphatic polyester with an extruder, kneading and reacting, a high concentration of the compound It can be carried out by a method of kneading and reacting a blend chip obtained by mixing an aliphatic polyester master chip and an aliphatic polyester homochip with an extruder or the like.

  In the biodegradable nonwoven fabric of the present invention, in order to obtain a biodegradable nonwoven fabric excellent in hydrolysis resistance, the biodegradable nonwoven fabric is formed with a glycidyl-modified compound having isocyanuric acid as a basic skeleton represented by the above [Chemical Formula 1]. It is important that part or all of the terminal carboxyl groups of the aliphatic polyester resin that is the raw material of the constituent fiber is blocked, and the fiber form is not particularly limited. The fineness can also be used in the range usually used for nonwoven fabrics.

  However, it is preferable that the hydrolysis resistance can be adjusted according to the intended use. However, the hydrolysis resistance can be adjusted by adjusting the content of the glycidyl-modified compound having isocyanuric acid as a basic skeleton represented by [Chemical Formula 1]. In addition to adjustment, it can also be controlled by fiber form. For example, a biodegradable non-woven fabric is composed of a core-sheath composite fiber made of an aliphatic polyester resin in which both the core component and the sheath component have a carboxyl group at the molecular chain terminal, and only the sheath component resin of the core-sheath composite fiber Is an aliphatic polyester resin containing at least one compound represented by the general formula [Chemical Formula 1], wherein a part or all of the terminal carboxyl groups are blocked by the compound, the sheath component ratio It is possible to adjust the hydrolysis resistance of the biodegradable nonwoven fabric by adjusting. The core-sheath type composite fiber may be a so-called sea-island type composite fiber having many core components, or may be a biodegradable resin in which the core component resin and the sheath component resin are different.

  In the biodegradable nonwoven fabric of the present invention, when the core-sheath composite fiber is applied to adjust the hydrolysis resistance of the biodegradable nonwoven fabric, the sheath component ratio is preferably 5 to 70 vol%, more preferably 10 ~ 60 vol%. When the sheath component ratio is less than 5 vol%, the core component resin to which the hydrolysis-resistant stabilizer is not added is easily exposed on the fiber surface during the production or use of the biodegradable nonwoven fabric. Since the progress is promoted and the hydrolyzability of the biodegradable nonwoven fabric cannot be adjusted, it is not preferable. On the other hand, when the sheath component ratio exceeds 70 vol%, the hydrolyzability of the biodegradable nonwoven fabric is substantially impossible to adjust, which is not preferable. The core-sheath-type conjugate fiber used in the present invention can be produced using a known core-sheath-type conjugate fiber production apparatus, and the resin serving as the core component and the resin serving as the sheath component are separated into separate polymer introduction tubes. From the above, it can be obtained by using a composite spinneret that can be filtered (aggregated) in a split flow state after being filtered in the respective filtration chambers.

  The terminal carboxyl group concentration of the aliphatic polyester resin used as the raw material of the fiber constituting the biodegradable nonwoven fabric of the present invention is preferably 0 to 20 equivalent / ton, more preferably 0 to 15 equivalent / ton. 0 to 10 equivalent / ton is more preferable. If the terminal carboxyl group concentration is 20 equivalents / ton or less, the desired sufficient hydrolysis resistance can be obtained. In addition, the terminal carboxyl group concentration as used in the field of this invention means the value measured with the measuring method mentioned later.

  In the biodegradable nonwoven fabric of the present invention, the molecular weight of the aliphatic polyester resin that is the raw material of the fibers constituting the biodegradable nonwoven fabric is the weight average molecular weight Mw of 80,000 to 500,000, and the weight average molecular weight is divided by the number average molecular weight Mn. In general, Mw / Mn representing molecular weight distribution is preferably in the range of 1.4 to 4.0, Mw is in the range of 100,000 to 450,000, and Mw / Mn is in the range of 1.6 to 3.6. It is more preferable that Mw is in the range of 120,000 to 400,000 and Mw / Mn is in the range of 1.8 to 3.2. When the fiber constituting the biodegradable nonwoven fabric is the above-described core-sheath type composite fiber, each of the core component resin and the sheath component resin is preferably in the above range, but the core component resin and the sheath component resin are the same. In the case of an aliphatic polyester resin, a mixed resin including a core component resin and a sheath component resin may be within the above range. A weight average molecular weight Mw of 80,000 or more is preferable because sufficient fiber strength can be obtained. On the other hand, if the weight average molecular weight Mw is 500,000 or less, the viscosity of the polymer extruded from the die becomes poor and the spinnability of the polymer cannot be high-speed drawn so that it becomes unstretched and sufficient fiber strength is obtained. It is no longer impossible. Further, when Mw / Mn, which generally represents the molecular weight distribution divided by the number average molecular weight, is 1.4 or more, when a biodegradable nonwoven fabric is produced, it is caused by the occurrence of fiber group vibrations just below the spinneret. This is preferable because thread breakage is less likely to occur. On the other hand, if Mw / Mn is 4.0 or less, it is preferable that when producing a biodegradable nonwoven fabric, the spinnability deteriorates and frequent occurrence of yarn breakage does not occur. In addition, the weight average molecular weight and weight average molecular weight as used in the field of this invention mean the polystyrene conversion value calculated | required by the gel permeation chromatography method mentioned later.

  In the biodegradable nonwoven fabric of the present invention, for the characteristic values such as fabric weight, thickness, strength, and air flow of the nonwoven fabric, respective uses such as civil engineering materials, agricultural materials, living materials, industrial materials, vehicle materials, building materials, etc. Is not limited as long as it is a characteristic value suitable for the non-woven fabric. However, the strength elongation index holding ratio as an index of hydrolysis resistance of the nonwoven fabric is preferably 50% or more, and preferably 60% or more. Is more preferable, and 70% or more is more preferable. As will be described later in Examples, the strong elongation index is represented by a product of the tensile strength and breaking elongation of the nonwoven fabric multiplied by a half, and is also called toughness.

  The civil engineering material in the present invention is not limited as long as it is a material used for civil engineering, for example, a herbicidal sheet, tree planting pot, root winding material, embankment reinforcing material, slope protection material, revetment sheet, Soft ground surface treatment material, anti-suction material, tunnel drainage material, etc.

  The agricultural material in the present invention is not limited at all as long as it is a material used for agriculture and horticulture, for example, a beak sheet, a seedling pot, a seedling sheet, a root-preventing sheet, an increased sugar content sheet, a multi-sheet, Insect repellent sheets, insect repellent bags, agricultural tape materials, seed vat sheets, seed vat tapes, etc.

  The living material in the present invention is not limited at all as long as it is a material used for daily goods. For example, handbags, souvenir bags, wrapping materials, suit covers, cleaning covers, simple clothing, masks, wipers, pillow covers , Futon storage bags, electrical product packaging materials, food packaging materials, D-bags, draining bags, etc.

  The industrial material in the present invention is not limited at all as long as it is a material used for industrial purposes, and includes, for example, a filter, an electric wire holding material, an industrial wiper, an abrasive cloth, a battery separator, and the like.

  The vehicle material in the present invention is not limited at all as long as it is a material used for various vehicles such as automobiles, trains, aircrafts, ships, etc. For example, ceiling materials, floor mats, sheet materials, noise prevention materials Spare tire cover materials, trunk room interior materials, airbag wrapping materials, etc.

  The building material in the present invention is not limited as long as it is a material used for construction, for example, a moisture permeable waterproof sheet, a roofing roofing material, a roofing material, a waterproof coating material, a sound insulating material, a soundproofing material, It is a sound-absorbing material, a heat insulating material, a decorative sheet backing material, and the like.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited by these Examples. In addition, each characteristic value in the following Example is measured by the following method.

(1) Mw (weight average molecular weight) and Mn (number average molecular weight)
Tetrahydrofuran was mixed with the chloroform solution of the sample to prepare a measurement solution, which was measured at 25 ° C. using a gel permeation chromatograph (GPC) Waters 2690 manufactured by Waters, and Mw was determined in terms of polystyrene. The measurement was performed at three points for each sample, and the average value was defined as each Mw.

(2) Melting point (° C)
Using a differential scanning calorimeter DSC-2 manufactured by Perkin Elma Co., Ltd., measuring at a temperature rising rate of 20 ° C./min, reading the temperature that gives the extreme value in the melting endothermic curve to the first decimal place, The value rounded to the first decimal place was taken as the melting point.

(3) Single fiber fineness (dtex)
Ten small piece samples are taken at random from the nonwoven fabric, photographed at 500 to 3000 times with a scanning electron microscope, 10 from each sample, 100 fiber diameters are measured, and the fiber diameter is calculated from the average value. The fineness was calculated by correcting this with the density of the polymer. The second decimal place of the calculated value was rounded off.

(4) Weight per unit (g / m ² )
Based on JIS L 1906 (2000 edition) 5.2, three samples of 30 cm in the vertical direction and 30 cm in the horizontal direction were taken, the weight of each sample was measured, and the average value of the obtained values per unit area The weight per unit area <A> of the nonwoven fabric was calculated by rounding off the first decimal place of the obtained value.

(5) Strong elongation index retention rate (%)
Each sample of width direction 5 cm × length direction 30 cm (longitudinal direction) and length direction 5 cm × width direction 30 cm (lateral direction) of the nonwoven fabric was placed in a constant temperature bath at a temperature of 60 ± 5 ° C. and a relative humidity of 80 ± 5%. It was left in the state suspended for days.

Based on JIS L 1906 (2000 edition) 5.3.1, samples left in the above-mentioned temperature-controlled bath and samples before being left in the temperature-controlled bath (collected simultaneously when collecting samples left in the temperature-controlled bath) ) Under the conditions of a grip interval of 20 cm and a tensile speed of 10 cm / min, the tensile test was carried out at 5 points in each of the machine direction and the transverse direction, and the maximum strength (N / 5 cm unit, decimal point) Second rounded) and elongation at break (% units, rounded to the second decimal place). The sample was left in a constant temperature bath, a maximum strength of the average value of the longitudinal five points to T _MD14, the maximum strength of the average value of the lateral direction of 5 T _CD14, an average elongation at break in the longitudinal direction 5 points E _MD14 , the average value of breaking elongation at 5 points in the horizontal direction is E _CD14, and for samples before being left in the thermostatic chamber, the average value of the maximum strength at 5 points in the vertical direction is T _MD0 , and the maximum strength at 5 points in the horizontal direction the average value _{T CD0,} the average of breaking elongation in the longitudinal direction 5 points _{E MD0,} the average value of the elongation at break in the transverse direction 5 points was _{E CD0.} The average value for each of the five points was rounded off to the second decimal place. Then, using these measured values, the strength elongation index retention was calculated by the following formula. Also in this case, the value rounded to the second decimal place was adopted.
Strength and elongation index retention _{(%) = 100 × {(} T MD14 × √E MD14) + (T CD14 × √E CD14)} / {(T MD0 × √E MD0) + (T CD0 × √E CD0) }
Each sample used for the measurement had a size of 5 cm × 30 cm, and the basis weight was measured in advance before being put into each tank. The difference from the basis weight of the same sample measured in the above (3) was within ± 2%. Only the thing was used for the measurement of the strength index retention.

(6) Carboxyl group terminal concentration (equivalent / ton)
The precisely weighed sample was dissolved in o-cresol (5% moisture), and an appropriate amount of dichloromethane was added to this solution, followed by titration with a 0.02 N KOH methanol solution. At this time, an oligomer such as lactide, which is a cyclic dimer of lactic acid, is hydrolyzed to generate a carboxyl group terminal, so that all of the carboxyl group terminal of the polymer, the carboxyl group terminal derived from the monomer, and the carboxyl group terminal derived from the oligomer are combined. The carboxyl group terminal concentration obtained is obtained.

(7) Color of aliphatic polyester Non-woven fabric is laminated to such an extent that the white plate of the base can be ignored, and the b ^* value of L ^* a ^* b ^* color system is measured using a spectrophotometer CM-3700d manufactured by Minolta. did. At this time, D65 (color temperature 6504K) was used as a light source, measurement was performed in a 10 ° visual field, and a color tone having a b ^* value of 5 or less was considered good.

Example 1
TEPIC (manufactured by Nissan Chemical Industries, Ltd.) is added to a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melting and kneading to produce a chip having a TEPIC content of 5.0 wt%. did. The prepared TEPIC 5.0 wt% chip and a polylactic acid resin chip having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. are mixed so that the mixing ratio of the TEPIC 5.0 wt% chip is 20%. It was mixed with an apparatus to obtain a raw material for the spunbonded nonwoven fabric. The obtained raw material was melted at 230 ° C., spun from the pores at a die temperature of 235 ° C., spun at a spinning speed of 4300 m / min by an ejector, and the web obtained by collecting on the moving net conveyor was A spunbonded non-woven fabric having a single fiber fineness of 1.6 dtex and a basis weight of 30 g / m ² was manufactured by thermocompression bonding with an embossing roll and a flat roll having a convex area of 16% at a temperature of 145 ° C. and a linear pressure of 25 kg / cm ² . . The resulting spunbonded nonwoven fabric had a terminal carboxyl group concentration of 5.0 equivalent / ton, Mw of 210000, Mw / Mn of 2.31, and a strong elongation index retention of 81.0%.

(Example 2)
DAMGIC (manufactured by Shikoku Kasei Kogyo Co., Ltd.) is added to a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melt kneading to produce a chip having a DAMGIC content of 5.0 wt%. did. The prepared DAMGIC 5.0 wt% chip and a polylactic acid resin chip having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. are mixed so that the mixing ratio of the DAMGIC 5.0 wt% chip is 30%. It was mixed with an apparatus to obtain a raw material for the spunbonded nonwoven fabric. The obtained raw material was melted at 230 ° C., spun from the pores at a die temperature of 235 ° C., spun at a spinning speed of 4100 m / min by an ejector, and the web collected on the moving net conveyor was collected. A spunbonded non-woven fabric with a single fiber fineness of 1.2 dtex and a basis weight of 50 g / m ² was manufactured by thermocompression bonding with an embossing roll and a flat roll having a convex area of 16% at a temperature of 145 ° C. and a linear pressure of 25 kg / cm ² . . The resulting spunbonded nonwoven fabric had a terminal carboxyl group concentration of 7.8 equivalent / ton, Mw of 162000, Mw / Mn of 1.84, and a strong elongation index retention of 77.7%.

(Example 3)
TEPIC (manufactured by Nissan Chemical Industries, Ltd.) is added to a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melting and kneading to produce a chip having a TEPIC content of 5.0 wt%. did. The prepared TEPIC 5.0 wt% chip and a polylactic acid resin chip having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. are mixed so that the mixing ratio of the TEPIC 5.0 wt% chip is 20%. It was mixed with an apparatus to obtain a raw material for the spunbonded nonwoven fabric. The obtained raw material was a sheath component, a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C., and the core component and the sheath component were melted at 230 ° C. After spinning as a core-sheath composite fiber with a sheath component ratio of 20 vol% from the pores at ℃, the web spun by an ejector at a spinning speed of 4300 m / min and collected on a moving net conveyor A spunbonded nonwoven fabric having a single fiber fineness of 1.6 dtex and a basis weight of 30 g / m ² was manufactured by thermocompression bonding with an embossing roll having an area of 16% under conditions of a temperature of 145 ° C. and a linear pressure of 25 kg / cm. The resulting spunbonded nonwoven fabric had a terminal carboxyl group concentration of 19.1 equivalent / ton, Mw of 171000, Mw / Mn of 1.90, and a strong elongation index retention of 66.0%.

Example 4
MADGIC (manufactured by Shikoku Kasei Kogyo Co., Ltd.) is added to polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melt-kneading to produce a chip with a MADGIC content of 5.0 wt%. did. The prepared MADGIC 5.0 wt% chip and a polylactic acid resin chip having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. are mixed so that the mixing ratio of the MADGIC 5.0 wt% chip is 40%. It was mixed with an apparatus to obtain a raw material for the spunbonded nonwoven fabric. The obtained raw material is a sheath component, a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. is used as a core component raw material, and both the core component and the sheath component are melted at 230 ° C. After spinning as a core-sheath composite fiber with a sheath component ratio of 40 vol% from the pores at 235 ° C., the web spun by an ejector at a spinning speed of 4300 m / min and collected on a moving net conveyor A spunbonded nonwoven fabric having a single fiber fineness of 1.6 dtex and a basis weight of 100 g / m ² was manufactured by thermocompression bonding with an embossing roll having a surface area of 16% and a temperature of 145 ° C. and a linear pressure of 25 kg / cm. The resulting spunbonded nonwoven fabric had a terminal carboxyl group concentration of 12.7 equivalent / ton, Mw of 165000, Mw / Mn of 1.78, and a strong elongation index retention of 73.0%.

  The properties of the obtained nonwoven fabric are as shown in Table 1, but all of the nonwoven fabrics of Examples 1 to 6 had a strength retention of 50.0% or more and were excellent in hydrolysis resistance. In addition, the nonwoven fabrics of Examples 1 to 6 were free from the generation of irritating odors when manufactured, had a favorable manufacturing environment, and had a good color tone.

(Comparative Example 1)
A polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalents / ton and a melting point of 168 ° C. is used as a raw material, melted at 230 ° C., spun from the pores at a die temperature of 235 ° C., and a spinning speed of 4300 m / min by an ejector. The web obtained by spinning and collecting on the moving net conveyor was thermocompression bonded with an embossing roll and a flat roll having a convex area of 16% at a temperature of 145 ° C. and a linear pressure of 25 kg / cm, A spunbonded nonwoven fabric having a single fiber fineness of 1.6 dtex and a basis weight of 30 g / m ² was produced. The resulting spunbonded nonwoven fabric had a terminal carboxyl group concentration of 22.8 equivalent / ton, Mw of 150,000, Mw / Mn of 1.64, and a strong elongation index retention of 44.2%.

(Comparative Example 2)
To 400 g of 4,4′-dicyclohexylmethane diisocyanate, 36 g of cyclohexylamine is added as an end-capping agent, and 2 g of 3-methyl-1-phenyl-2-phospholene-1-oxide is added as a carbodiimidization catalyst. For 12 hours to obtain a polycarbodiimide compound having a polymerization degree of 8 (hereinafter referred to as polycarbodiimide compound A).

A polycarbodiimide compound A was added to a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melt kneading to produce a chip having a polycarbodiimide compound A content of 5.0 wt%. The produced polycarbodiimide compound A 5.0 wt% chip, the polylactic acid resin chip having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C., the mixing ratio of the polycarbodiimide compound A 5.0 wt% chip is 20%. The mixture was mixed with a chip mixer so that the raw material of the spunbond nonwoven fabric was obtained. The obtained raw material was melted at 230 ° C., spun from the pores at a base temperature of 235 ° C., spun at a spinning speed of 4000 m / min by an ejector, and the web collected on the moving net conveyor was A spunbonded nonwoven fabric having a single fiber fineness of 1.8 dtex and a basis weight of 50 g / m ² was produced by thermocompression bonding with an embossing roll and a flat roll having a part area of 16% under the conditions of a temperature of 145 ° C. and a linear pressure of 25 kg / cm. The resulting spunbonded nonwoven fabric had a terminal carboxyl group concentration of 5.9 equivalents / ton, Mw of 165000, Mw / Mn of 1.80, and a strong elongation index retention of 78.2%.

(Comparative Example 3)
2,2'-m-phenylenebis (2-oxazoline) (hereinafter referred to as PBO) is added to a polylactic acid resin having a terminal carboxyl group concentration of 22.8 equivalent / ton and a melting point of 168 ° C. by melt-kneading. A raw material chip having a content of 0.5 wt% was produced. The obtained raw material was melted at 230 ° C., spun from the pores at a base temperature of 235 ° C., spun at a spinning speed of 4000 m / min by an ejector, and the web collected on the moving net conveyor was A spunbonded nonwoven fabric having a single fiber fineness of 1.8 dtex and a basis weight of 50 g / m ² was produced by thermocompression bonding with an embossing roll and a flat roll having a part area of 16% under conditions of a temperature of 145 ° C. and a linear pressure of 25 kg / cm. The resulting spunbonded nonwoven fabric had a terminal carboxyl group concentration of 21.2 equivalent / ton, Mw of 155000, Mw / Mn of 1.66, and a strong elongation index retention of 46.2%.

  The properties of the obtained nonwoven fabric are as shown in Table 1, but the nonwoven fabric of Comparative Example 1 had a strength index retention of less than 50.0% and was inferior in hydrolysis resistance. In addition, although the nonwoven fabric of Comparative Example 2 had a strong elongation index retention of 50.0% or more, an irritating odor was generated during production, which was difficult to apply to actual production, and the color of the nonwoven fabric was poor. there were. Moreover, the nonwoven fabric of the comparative example 3 had little terminal carboxyl group blocking effect, the strength index retention rate was less than 50.0%, and was inferior to hydrolysis resistance.

The biodegradable nonwoven fabric of the present invention has a favorable production environment without generation of irritating odors when produced, and a biodegradable nonwoven fabric having excellent hydrolysis resistance and good color tone is obtained. Civil engineering materials such as sheets and planting pots, agricultural materials such as bedding sheets and seedling pots, living materials such as handbags and wrapping materials, industrial materials such as filters and wire clamps, ceiling materials, floor mats, etc. It can be applied to building materials such as vehicle materials, moisture-permeable waterproof sheets, and roofing materials.

Claims (11)

An aliphatic polyester resin having a carboxyl group at the molecular chain end, the molecular weight of the aliphatic polyester resin being in the following range , comprising at least one compound represented by the general formula [Chemical Formula 1], A method for producing a biodegradable spunbonded nonwoven fabric comprising a fiber comprising an aliphatic polyester resin in which a part or all of the carboxyl groups are blocked with a compound, wherein spinning is performed at a spinning speed of 4100 to 4300 m / min. A method for producing a biodegradable spunbond nonwoven fabric .

(Here, at least one of R _{1 to} R ₃ is a glycidyl ether or a glycidyl ester, and the rest are functional groups such as hydrogen, an alkyl group having 1 to 10 carbon atoms, a hydroxyl group, and an allyl group).
Mw: 80,000 to 500,000
Mw / Mn: 1.4 to 4.0
Here, Mw is a weight average molecular weight, and Mn is a number average molecular weight. A biodegradable spunbonded nonwoven fabric containing a core-sheath composite fiber comprising an aliphatic polyester resin in which both the core component and the sheath component have a carboxyl group at the molecular chain terminal, and the molecular weight of the aliphatic polyester resin is in the following range. And only the sheath component resin of the core-sheath composite fiber contains at least one compound represented by the general formula [Chemical Formula 1], and a part or all of the carboxyl groups are blocked by the compound. A method for producing a biodegradable spunbonded nonwoven fabric , which is an aliphatic polyester resin and the sheath-sheath component ratio of the core-sheath composite fiber is 5 to 70 vol% , comprising spinning at a spinning speed of 4100 to 4300 m / min. A method for producing a biodegradable spunbond nonwoven fabric .

(Here , at least one of R _{1 to} R ₃ is a glycidyl ether or a glycidyl ester, and the rest are functional groups such as hydrogen, an alkyl group having 1 to 10 carbon atoms, a hydroxyl group, and an allyl group).
Mw: 80,000 to 500,000
Mw / Mn: 1.4 to 4.0
Here, Mw is a weight average molecular weight, and Mn is a number average molecular weight. The method for producing a biodegradable spunbonded nonwoven fabric according to claim 1 or 2, wherein the terminal carboxyl group concentration is 0 to 20 equivalents / ton. The method for producing a biodegradable spunbonded nonwoven fabric according to any one of claims 1 to 3, wherein the content of the compound of [Chemical Formula 1] is 0.02 to 10 wt% with respect to the total amount of the aliphatic polyester resin. The method for producing a biodegradable spunbonded nonwoven fabric according to any one of claims 1 to 4, wherein the aliphatic polyester resin is a polylactic acid resin. Civil engineering material which consists of a biodegradable spunbond nonwoven fabric obtained by the manufacturing method in any one of Claims 1-5 . An agricultural material comprising a biodegradable spunbonded nonwoven fabric obtained by the production method according to any one of claims 1 to 5 . The living material which consists of a biodegradable spunbonded nonwoven fabric obtained by the manufacturing method in any one of Claims 1-5 . The industrial material which consists of a biodegradable spunbonded nonwoven fabric obtained by the manufacturing method in any one of Claims 1-5 . The vehicle material which consists of a biodegradable spunbonded nonwoven fabric obtained by the manufacturing method in any one of Claims 1-5 . Building materials made of biodegradable spunbond nonwoven fabric obtained by the production method according to any one of claims 1-5.