JP3247176B2 - Biodegradable latently crimpable composite filament and nonwoven fabric thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a nonwoven or woven or knitted fabric which is biodegradable, has excellent mechanical strength, dimensional stability, stretchability and bulkiness, is highly flexible, and has thermal adhesiveness. The present invention relates to a conjugate long fiber suitable for obtaining and a nonwoven fabric thereof.

[0002]

2. Description of the Related Art Conventionally, nonwoven fabrics of viscose rayon short fibers obtained by a dry method or a solution immersion method, nonwoven fabrics of kipura rayon or viscose rayon long fibers obtained by a wet spunbond method, chitin, atelocollagen, etc. Various biodegradable nonwoven fabrics are known, such as a nonwoven fabric made of chemical fibers of natural products and a spunlace nonwoven fabric made of cotton. However, these conventional biodegradable nonwoven fabrics have low mechanical strength of the constituent material of the nonwoven fabric itself and are hydrophilic, so that the mechanical strength is significantly reduced during water absorption and wetness. There were various problems such as poor stability, poor flexibility, and lack of thermal adhesiveness because the material itself was non-thermoplastic.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, has biodegradability, is excellent in mechanical strength, dimensional stability, stretchability and bulkiness, is flexible, and has thermal bonding. It is an object of the present invention to provide a composite long fiber suitable for obtaining a nonwoven fabric or a woven or knitted fabric having properties and a nonwoven fabric thereof.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention relates to a laminated composite continuous fiber in which a high-melting-point biodegradable thermoplastic polymer component and a lower-melting-point biodegradable thermoplastic polymer component are joined to a laminating mold. The present invention also provides a biodegradable latently crimpable conjugate long fiber characterized by having latent crimping ability. Further, in the present invention, the core portion is composed of a high-melting-point biodegradable thermoplastic polymer component, and the sheath portion is composed of a low-melting-point biodegradable thermoplastic polymer component. 2
The gist of the present invention is a nonwoven fabric comprising eccentric core-sheath composite long fibers having a crimp of 5 mm or more, and wherein the constituent fibers are partially thermally bonded to each other. In addition, the present invention provides a biodegradable thermoplastic polymer component having a high melting point and a biodegradable thermoplastic polymer component having a lower melting point than the polymer, which are joined to each other in a bonding mold, and the number of crimps is 25 / 25
The non-woven fabric is composed of a laminated composite long fiber having a crimp of not less than mm and is characterized in that the constituent fibers are partially thermally bonded to each other.

Next, the present invention will be described in detail. The biodegradable thermoplastic polymer in the present invention is a thermoplastic aliphatic polyester polymer having biodegradability, and is composed of, for example, polyglycolic acid or polylactic acid such as poly (α-hydroxy acid). A polymer or a copolymer thereof; a poly (ω-hydroxyalkanoate) such as poly (ε-caprolactone) and poly (β-propiolactone); and poly-3-hydroxypropionate. , Poly-3-hydroxybutyrate, poly-3-
Poly (such as hydroxycaprolate, poly-3-hydroxyheptanoate, poly-3-hydroxyoctanoate and copolymers thereof with poly-3-hydroxyvalerate and poly-4-hydroxybutyrate) β-hydroxyalkanoate). Examples of the polycondensate of glycol and dicarboxylic acid include polyethylene oxalate, polyethylene succinate, polyethylene adipate, polyethylene azelate, polybutylene oxalate, polybutylene succinate, polybutylene adipate, polybutylene sebacate, Examples thereof include polyhexamethylene sebacate, polyneopentyl oxalate, and a copolymer thereof. Further, the aliphatic polyester, polycapramide (nylon 6), polytetramethylene adipamide (nylon 4
6), polyhexamethylene adipamide (nylon 6
6), aliphatic polyesteramide-based copolymers which are co-condensed with aliphatic polyamides such as polyundecanamide (nylon 11) and polylaurolactamide (nylon 12). In the present invention, a thermoplastic polymer other than those described above as the biodegradable thermoplastic polymer can be used as long as it is biodegradable. In the present invention, if necessary, various additives such as matting agents, pigments, light stabilizers, heat stabilizers, antioxidants, etc. may be added to the biodegradable thermoplastic polymer described above. Can be added in a range that does not impair the effects of the present invention.

In the present invention, the biodegradable thermoplastic composite fiber has a melting point selected from the above polymers that differs by 3 ° C. or more and 150 ° C. or less.
The core is composed of a high-melting-point biodegradable thermoplastic polymer component, and the sheath is composed of a low-melting-point biodegradable thermoplastic polymer component. As described above, a biodegradable thermoplastic polymer component having a high melting point and a biodegradable thermoplastic polymer component having a lower melting point than the polymer so as to have an eccentric core-sheath type composite form in which both polymer components are arranged. Are bonded so as to have a composite form of a lamination type, and have latent crimpability. In this composite continuous fiber, the difference in melting point between the two polymer components is 3
When the temperature is lower than ℃, a nonwoven web is prepared by using the obtained fiber and subjected to a heat treatment to form a nonwoven fabric. Not only the polymer component having a low melting point but also the polymer component having a high melting point are preferably softened and melted. Therefore, in the present invention,
The melting point difference is 3 ° C. or more, preferably 5 ° C. or more, and more preferably 10 ° C. or more. On the other hand, if the difference in melting point exceeds 150 ° C., the difference in melting point between both polymer components is so large that it is difficult to control the spinning temperature in the spinning nozzle pack when performing composite spinning using both polymers, which is not preferable. . In the present invention, when the low-melting point biodegradable thermoplastic polymer having a melting point of 60 ° C. or higher, preferably 80 ° C. or higher, and more preferably 100 ° C. or higher is used, the long-lasting thermoplastic polymer having the low-melting point polymer component can be used. It is preferable that the nonwoven fabric or the woven or knitted fabric is provided with a certain heat resistance when the nonwoven fabric or the woven or knitted fabric is made of fibers.
In this composite continuous fiber, the composite ratio, that is, the weight ratio of the low melting polymer component to the high melting polymer component is 1/5.
５5/1 is preferred. If the ratio of the low-melting polymer component to the high-melting polymer component 1 exceeds 5, the strength of long fibers decreases, or the stretchability and bulkiness of the nonwoven fabric obtained using the long fibers are poor. On the other hand, if the ratio of the high-melting polymer component 5 to the low-melting polymer component is less than 1, the non-woven fabric obtained by using this long fiber will be hardened. Since the strength of the heat-bonded portion between the constituent fibers is reduced, or the stretchability and bulkiness of the nonwoven fabric are inferior, both are not preferable.
/ 5 to 5/1, preferably 2/3 to 3/2.

As described above, the composite long fiber is joined so that the high melting point polymer component and the low melting point polymer component have an eccentric core-sheath type composite form or a laminated type composite form. And has a latent crimping ability, and by having such a composite form, it is subjected to a relaxation heat treatment at a temperature near the melting point of the low melting point thermoplastic polymer component to reveal the latent crimp, thereby causing crimping. A crimp of several 25 pieces / 25 mm or more is developed. Therefore, when a non-woven fabric or a woven or knitted fabric is formed by using the long fiber in which the latent crimp has become apparent, the non-woven fabric or the woven or knitted fabric can have elasticity and bulkiness.

In the present invention, the composite filament has a single fiber fineness of 0.5 to 10 denier. If the single fiber fineness is less than 0.5 denier, it is discharged from the spinning nozzle surface during melt spinning. On the other hand, if the filament size exceeds 10 denier, the non-woven fabric or woven or knitted fabric obtained using this filament becomes coarse and hard with a rough texture. However, none of them are preferable because their quality is inferior.

The nonwoven fabric according to the present invention is composed of the above-mentioned conjugated filaments in which the latent crimp as described above has been manifested and a crimp having a number of crimps of 25/25 mm or more has been developed, and the constituent fibers are partially Is thermally bonded to the substrate. This nonwoven fabric has excellent elasticity and bulkiness because the constituent fibers have a number of crimps of 25 crimps / 25 mm or more. Further, this nonwoven fabric has a partial heat bonding point formed between the constituent fibers by a known heat bonding process, whereby the form of the nonwoven fabric is maintained, and the nonwoven fabric has excellent mechanical strength and Dimensional stability is developed.

In the present invention, the nonwoven fabric comprising the conjugated long fibers preferably has a basis weight of 10 g / m ² or more. In this nonwoven fabric, the basis weight is 10 g / m
^If it is less than ² , the mechanical strength of the nonwoven fabric itself is low, the bulkiness is inferior, the quality of the nonwoven fabric is poor such as rough formation, or the productivity in preparing the nonwoven fabric is unfavorable. .

The long fiber according to the present invention can be efficiently produced by the following method. That is,
According to a conventional method, two types of polymers selected from the biodegradable thermoplastic polymers having melting points different from 3 ° C. or more and 150 ° C. or less are melt-composited into an eccentric core-sheath type or a laminated type. The spun yarn is cooled using a cooling air stream or cooling water, and then wound once to form an undrawn filament yarn.
Alternatively, it can be obtained by performing cold stretching or hot stretching continuously in one or more stages without winding once. The spinning temperature at the time of melt spinning depends on the melting point and the degree of polymerization of the polymer to be used.
It is desirable that If the spinning temperature is lower than 120 ° C., it becomes difficult to melt-extrude the polymer.
When the temperature is higher than 00 ° C., the thermal decomposition of the polymer becomes remarkable, so that high-strength fibers cannot be obtained. The total draw ratio when drawing an undrawn filament yarn is:
Depending on the strength level of the target long fiber, usually 2.0 to
It is 4.0 times, whereby a long fiber having a tensile strength of 3.0 g / denier or more can be obtained.

The nonwoven fabric comprising the long fibers in the present invention can be efficiently produced by a known so-called spunbond method. That is, two kinds of polymers selected from the biodegradable thermoplastic polymers differing in melting point by at least 3 ° C. or more and 150 ° C. or less by an ordinary method into an eccentric core-sheath type or a laminated type. Molten composite spinning, the spun yarn is cooled using a cooling air stream, the spun yarn is taken up at high speed using a take-up means such as an air sucker, and collected and deposited on a moving collecting surface to form a web. age,
Subsequently, the obtained web is subjected to a heat bonding treatment to partially heat-bond the constituent fibers to each other, and then subjected to a relaxation heat treatment to reveal latent crimps of the constituent fibers. This nonwoven fabric can also be efficiently produced by a known so-called melt blown method. That is, as described above, two types of polymers are melt-combined and spun into an eccentric core-sheath type or a laminated type by a melt blown method, and the melt-spun polymer stream is heated to the same temperature as the melting temperature.
After being drawn and thinned by a high-pressure air stream at a temperature about 30 ° C. higher than the melting temperature, cooled, collected and deposited on a moving collecting surface to form a web, and then the obtained web is subjected to a thermal bonding treatment. After the constituent fibers are partially thermally bonded to each other, they can be obtained by performing relaxation heat treatment to make latent crimps of the constituent fibers visible.

When the web is subjected to a partial heat bonding treatment, a known method can be adopted. For example, a method in which the web is passed between a roller composed of a heated embossing roller and a metal roller having a smooth surface, a method using a hot air drying device, or a method using an ultrasonic fusion device. When using a heated embossing roller to partially heat bond the fibers present in the embossed pattern,
When the pressing area ratio of the embossing roller is 5 to 50%, and when the pressing area ratio is less than 5%, the mechanical strength of the nonwoven fabric is reduced due to the small number of spot-like fused areas, and good dimensional stability can be obtained. On the other hand, if the pressed area ratio exceeds 50%, the nonwoven fabric becomes rigid and the flexibility is impaired. Further, the roller temperature is usually preferably set to a temperature lower by about 5 to 50 ° C. than the melting point of the thermoplastic polymer having a low melting point. Excellent strength and dimensional stability,
Moreover, a highly flexible nonwoven fabric can be obtained. The emboss pattern in the case of using the hot emboss roller is not particularly limited as long as the press contact area ratio is in the range of 5 to 50%, and it is round, elliptical, rhombic, triangular, T-shaped, and well. Any shape such as a mold may be used. In the case where fibers are partially thermally bonded to each other at the crossing points of the fibers using a hot-air drying device, the processing temperature depends on the processing time, but it is usually higher than the melting point of the low melting point thermoplastic polymer and higher. The temperature is preferably within a range of about 10 ° C. lower than the melting point of the thermoplastic polymer having the melting point. The partial heat bonding using a hot embossing roller, a hot air drying device or an ultrasonic fusing device, for example, may be a continuous process or a separate process.

When the web is subjected to a relaxation heat treatment to reveal the latent crimp of the constituent fibers, a known method can be employed. For example, there is a method in which the web is subjected to a relaxation heat treatment using a heating device such as a hot air drying device. When the web is subjected to relaxation heat treatment using a hot air drying apparatus, the treatment temperature depends on the treatment time, but it is usually preferable to set the temperature to about 5 to 30 ° C. lower than the melting point of the low melting point thermoplastic polymer. . The relaxation heat treatment using, for example, a hot-air drying device may be either a continuous process or a separate process.

[0015]

EXAMPLES Next, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In the examples, the measurement of each characteristic value was performed by the following method. Melting point (° C): Differential scanning calorimeter DS manufactured by PerkinElmer
Measured at a heating rate of 20 ° C / min using C-2 type,
The temperature at which an extreme value was obtained in the obtained melting endothermic curve was defined as the melting point. Melt flow rate value (g / 10 min): ASTM D1
238 (L). Tensile strength of long fiber (g / denier): JIS-L-10
The measurement was carried out according to the method described in No. 13. KGSM tensile strength (kg) of nonwoven fabric: JIS-L-10
The measurement was carried out according to the method described in 96A. That is, ten sample pieces each having a sample length of 10 cm and a sample width of 5 cm were prepared, and a constant-speed elongation type tensile tester (Tensilon UTM manufactured by Toyo Baldwin Co., Ltd.) was used for each sample piece in the longitudinal direction of the nonwoven fabric.
−4-1-100), elongate at a tensile speed of 10 cm / min, convert the average value of the obtained breaking load value (kg) into a basis weight of 100 g / m ^2, and convert the KGSM tensile strength (k
g). Number of crimps of nonwoven fabric constituent fibers (pieces / 25 mm): An enlarged photograph of nonwoven fabric constituent fibers was taken using a scanning electron microscope to determine the number of crimps.

Example 1 Melting point of 102 ° C. and melt flow rate of 10 g / 10
The polybutylene succinate polymer having a melting point of 118 ° C. and a melt flow rate of 5 g / 10 min as a high melting point component was used as a high melting point component. A spinning temperature of 205 ° C. and a composite ratio (weight ratio) of 1 are passed through a spinneret having 36 holes of a 6 mm bonded type (side-by-side type) composite spinning hole.
Melt spun into a laminating die under the condition of / 1, the spun yarn is cooled using a warm air stream at a temperature of 40 ° C, an oil agent is applied, the yarn is taken off at a take-up speed of 800 m / min, and the undrawn yarn A single-stage hot drawing is performed by using a heating roll at a temperature of 60 ° C. at a total draw ratio of 3.8 continuously without winding up, and a single-fiber fineness is 3.0 denier. I got The obtained composite continuous fiber had a tensile strength of 3.9 g / denier and had mechanical strength sufficient for practical use. When the long fibers were buried in the soil for two months and then taken out and observed, they had lost their form as a nonwoven fabric and were found to have excellent biodegradability.

Example 2 A polyethylene succinate polymer having a melting point of 102.degree. C. and a melt flow rate of 5 g / 10 min was treated with a low melting point component in the sheath, and a melting point of 118.degree. C. and a melt flow rate of 5 g / 1.
A 0 minute polybutylene succinate polymer was used as the high melting point component of the core, and both of these polymers were melted and passed through a spinneret having 36 composite spinning holes with a hole diameter of 0.5 mm to a spinning temperature of 2.
At 30 ° C and a compounding ratio (weight ratio) of 1/1, the composite yarn is melt-spun into an eccentric core-sheath type, and the spun yarn is cooled using a cooling airflow at a temperature of 20 ° C. The web is collected at a collecting speed of 3500 m / min and collected and deposited on a moving collecting surface to form a web having an eccentric core-sheath type composite filament having a single fiber fineness of 3.0 denier of 35 g / m ² . The obtained web was heated to a temperature of 85 ° C. and passed between an embossing roll having a pressed area ratio of 15% and a smoothing roll having the same temperature to partially heat-bond the fibers to each other. Relaxation heat treatment was performed using a hot air dryer at ℃ to obtain a nonwoven fabric. The obtained nonwoven fabric has a KGSM tensile strength of 11.0 kg / 5 cm in the vertical direction and 7.3 k in the horizontal direction.
g / 5 cm, the number of crimps was 28/25 mm, and it was excellent in mechanical strength, dimensional stability, elasticity, bulkiness, and flexibility. When the nonwoven fabric was buried in the soil for two months and then taken out and observed, it was confirmed that the nonwoven fabric had disappeared and had excellent biodegradability.

EXAMPLE 3 Melting point of 102 ° C. and melt flow rate of 35 g / 10
Of the polyethylene succinate polymer at a low melting point component in the sheath, melting point of 115 ° C. and melt flow rate of 40 g /
Example 3 Except that the polybutylene succinate polymer for 10 minutes was used as the high melting point component of the core and the spinning temperature was 228 ° C.
In the same manner as in the above, a web made of eccentric core-sheath type composite long fiber having a single fiber fineness of 2.0 denier and having a basis weight of 35 g / m ² was prepared, and the obtained web was heated to a temperature of 90 ° C. and pressed. After passing between an embossing roll having a rate of 18% and a smoothing roll having the same temperature to partially heat-bond the fibers to each other, the fibers were subjected to relaxation heat treatment using a hot-air dryer at a temperature of 100 ° C. to obtain a nonwoven fabric. The resulting nonwoven fabric has a KGSM tensile strength of 11.8 kg / 5 cm in the longitudinal direction and 7.6 kg / cm in the transverse direction.
With a size of 5 cm, the mechanical strength and dimensional stability were excellent, and the flexibility was high. When the nonwoven fabric was buried in the soil for two months and then taken out and observed, it was confirmed that the nonwoven fabric had disappeared and had excellent biodegradability.

Example 4 Melting point of 102 ° C. and melt flow rate of 20 g / 10
The polybutylene succinate polymer having a melting point of 115 ° C. and a melt flow rate value of 15 g / 10 min as a high melting point component,
These two polymers are melted and passed through a spinneret having 36 laminated (side-by-side) composite spinning holes with a hole diameter of 0.6 mm at a spinning temperature of 200 ° C. and a composite ratio (weight ratio).
Under the condition of 1/1, the melt composite spinning was carried out in a lamination type, and the spun yarn was cooled using a warm air flow having a temperature of 35 ° C., and then continuously taken at a take-up speed of 3300 m / min using an air sucker. The web is collected and deposited on a moving collecting surface to prepare a web having a basis weight of 30 g / m ² , which is made of a laminated conjugate long fiber having a single fiber fineness of 3.0 denier. ℃ and the pressed area ratio is 18
% Between the embossing roll and the smoothing roll at the same temperature to partially thermally bond the fibers to each other, and then subjected to a relaxation heat treatment using a hot-air dryer at a temperature of 95 ° C. to obtain a nonwoven fabric. The obtained nonwoven fabric has a KGSM tensile strength of 11.2 k in the longitudinal direction.
g / 5cm, transverse 7.2kg / 5cm, crimp number 31
Each piece / 25 mm was excellent in mechanical strength, dimensional stability, elasticity, and bulkiness, and was rich in flexibility. Also,
When the nonwoven fabric was buried in the soil for two months and then taken out and observed, it was confirmed that the nonwoven fabric had disappeared and had excellent biodegradability.

[0020]

Industrial Applicability The biodegradable latently crimped conjugate long fiber of the present invention has a core made of a high-melting-point biodegradable thermoplastic polymer component and a sheath part having a lower melting point than the polymer. To have a composite form of an eccentric core-sheath type in which both the polymer components are arranged as if they consist of a non-conductive thermoplastic polymer component, or a biodegradable thermoplastic polymer component having a high melting point and a polymer having a lower melting point than the polymer. It is bonded with a biodegradable thermoplastic polymer component so as to have a laminated composite form, and has latent crimping ability. It has biodegradability, mechanical strength, dimensional stability, and expansion and contraction. It is suitable for obtaining a nonwoven fabric or a woven or knitted fabric which is excellent in properties and bulkiness, has high flexibility, and has thermal adhesiveness. The nonwoven fabric made of this composite filament has the above-mentioned excellent properties, and is used for sanitary materials such as diapers and sanitary articles, disposable towels, wiping cloths, base fabrics for wrapping materials, household or It is suitable as a material for daily life-related materials such as fresh dust collection bags for business use and other waste treatment materials. In addition, this nonwoven fabric is useful from the viewpoint of protecting the natural environment since it is completely decomposed and disappears when left in the environment where many microorganisms are present, such as soil or water, after its use. Since it can be reused as fertilizer, it is useful from the viewpoint of resource reuse.

────────────────────────────────────────────────── (5) References JP-A-6-248516 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D01F 8/00-8/18

Claims (5)

(57) [Claims] 1. A laminated composite continuous fiber in which a high-melting-point biodegradable thermoplastic polymer component and a lower-melting-point biodegradable thermoplastic polymer component are joined to a lamination type. A biodegradable latently crimpable conjugate long fiber characterized by having latent crimping ability. 2. A core comprising a biodegradable thermoplastic polymer component having a high melting point, a sheath portion comprising a biodegradable thermoplastic polymer component having a lower melting point than said polymer, and having a number of crimps of 25/25 mm.
A nonwoven fabric comprising eccentric core-sheath composite long fibers having the above crimps, wherein the constituent fibers are partially thermally bonded to each other. 3. A biodegradable thermoplastic polymer component having a high melting point and a biodegradable thermoplastic polymer component having a lower melting point than the polymer are bonded to each other in a bonding mold, and the number of crimps is 25/25.
What is claimed is: 1. A nonwoven fabric, comprising laminated conjugate long fibers having a crimp of not less than mm, and wherein the constituent fibers are partially thermally bonded to each other. 4. The biodegradable latent crimpable composite length according to claim 1 , wherein the biodegradable thermoplastic polymer is an aliphatic polyester-based polymer or an aliphatic polyesteramide-based copolymer. fiber. 5. The nonwoven fabric according to claim 2, wherein the biodegradable thermoplastic polymer is an aliphatic polyester-based polymer or an aliphatic polyesteramide-based copolymer.