JP2000136479A - Nonwoven fabric for molding having biodegradability, its production and article having vessel shape using the same nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a readily moldable nonwoven fabric for molding having biodegradability and an article having vessel shape which is a molded product of the nonwoven fabric. SOLUTION: In this nonwoven fabric, fibers comprising polylactic acid and/or a thermoplastic polymer consisting mainly of polylactic acid are integrated and the polylactic acid and the thermoplastic polymer consisting mainly of the polylactic acid have >=100 deg.C melting point and double refractive index is <=0.015 and partly heat-fused areas in which fibers are mutually fused by softening or melting are arranged in scattered state and the sum of breaking elongation in vertical direction and breaking elongation in horizontal direction measured under atmosphere at 90 deg.C dry heat temperature are >=160%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable nonwoven fabric useful for deep drawing, a method for producing the same, and a container-shaped article made of the nonwoven fabric.

[0002]

2. Description of the Related Art Conventionally, fibers for industrial materials used for agriculture, civil engineering and fishing, sanitary materials such as sanitary napkins and diapers, and fibers used for daily life materials such as towels and wiping cloths include polyester. And synthetic fibers such as polyolefins and polyamides. Since these fibers are hardly decomposed when left in the natural world after use, there are various problems. Therefore, after use, these industrial materials, sanitary materials, living materials, etc. need to be buried or incinerated in the soil. Restrictions arise.

In order to solve such a problem, it is conceivable to use a material which can be decomposed in nature, that is, a biodegradable polymer. As such a biodegradable polymer,
Cellulose, cellulose derivatives, chitin, polysaccharides such as chitosan, poly-3-hydroxybutyrate and 3-hydroxybutyrate and 3-hydroxyvalerate copolymers produced by microorganisms, polyglycolide, polylactide,
Aliphatic polyesters such as polycaprolactone, polybutylene succinate and polyethylene succinate are known.

[0004] However, cellulose-based cotton and regenerated cellulose which are mainly used are inexpensive, but cannot be processed and molded because they are not thermoplastic. Also, if polyolefin, polyester fiber, or the like is used as the binder fiber, these fibers are difficult to biodegrade and pose a problem.
Poly (3-hydroxybutyrate) or a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate made by a microorganism is expensive and its use is limited. Polycaprolactone is a relatively inexpensive biodegradable polymer, but has a low melting point of about 60 ° C., which is a temperature that can occur during the distribution stage, and has a problem in terms of heat resistance.

Further, polybutylene succinate, polyethylene succinate and the like are relatively inexpensive biodegradable polymers and have a melting point exceeding 100 ° C., but their crystallization is slow, and therefore, fibers are not easily produced during spinning. There is a problem that adhesion is likely to occur between the yarns, and it is difficult to obtain a high elongation fiber or nonwoven fabric.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above problems and provides a nonwoven fabric for molding which has biodegradability and can be easily molded, and a container-shaped product which is a molded product thereof. Aim.

[0007]

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 provides (1) polylactic acid and / or
Alternatively, fibers made of a thermoplastic polymer mainly composed of polylactic acid are accumulated, and the polylactic acid and the thermoplastic polymer mainly composed of polylactic acid have a melting point of 100 ° C. or more and a birefringence of 0.015. In the following, a partial heat fusion region in which the fibers are fused or melted by softening or melting is provided in a scattered manner, and the longitudinal elongation at break and the transverse elongation at break measured in an atmosphere of dry heat of 90 ° C. And (2) a polylactic acid and / or a thermoplastic polymer mainly composed of polylactic acid, the melting point of which is 100 ° C. or more. Is melt-spun, and the obtained yarn is cooled and solidified.
Pulling and opening at 500 m / min or less, the birefringence is 0.0
A fibrous web consisting of fibers formed of a polymer of 15 or less, and thereafter, the constituent fibers are softened so that the fibers of the fibrous web are pseudo-bonded to each other, and subsequently, the fibers of the fibrous web are softened or melted to form a fiber web. (3) a method for producing a biodegradable nonwoven fabric for molding, wherein the fibrous web is integrated by forming a fused area in which the spaces are partially heat-fused into scattered spots; A container-shaped product characterized in that it is formed into a container shape by press-molding a non-woven fabric for molding; and (4) the non-woven fabric for molding is preheated to soften the constituent fibers, and then heated by a mold. A method for producing a container-shaped article, wherein the nonwoven fabric for molding is press-molded.

Therefore, according to the present invention, the melting point of polylactic acid and the thermoplastic polymer mainly composed of polylactic acid is 100 ° C.
As described above, since the nonwoven fabric formed of a specific fiber having a birefringence of 0.015 or less of the polymer is used as the base fabric for molding, the deep drawability at low temperatures is good.
Also, no thermal deterioration occurs. This molding nonwoven fabric has a wide range of temperature conditions associated with molding processing, the quality of molded products is extremely stable, there is no problem in operation in molding processing, and it has biodegradability for disposal after use. Is not a problem. In particular, since the polymer having biodegradability is a polylactic acid and / or a thermoplastic polymer mainly composed of polylactic acid, the spinnability is better than other biodegradable resins,
There is an advantage that thermal stability is also excellent. For this reason, food-type containers, aerated and molded containers for various living materials, various molded materials for automobile interiors, molded containers for raising seedlings, interior bedding materials,
It can be used for general purposes such as filters.

[0009]

Next, the present invention will be described in detail.
The polymer used for the constituent fibers of the biodegradable nonwoven fabric of the present invention is a polylactic acid and / or a thermoplastic polymer mainly composed of polylactic acid, and has a melting point of 100 ° C. or more. As such polylactic acid, poly (D-
Lactic acid), poly (L-lactic acid), and a copolymer of D-lactic acid and L-lactic acid. Such polylactic acid can be obtained by dehydration condensation of lactic acid or ring-opening polymerization of a cyclic ester of lactic acid. As a thermoplastic polymer mainly composed of polylactic acid, lactic acid, ε-caprolactones, α-hydroxybutyric acid, α-hydroxyisobutyric acid, α-hydroxy acids such as α-hydroxyvaleric acid, ethylene glycol, 1,
Glycols such as 4-butanediol and the like, dicarboxylic acids such as succinic acid and sebacic acid, and aliphatic carboxylic acids such as lauric acid and stearic acid copolymerized by one kind or two or more kinds can be used. The copolymerization can be controlled so as to lower the melting point.

As described above, the present invention uses polylactic acid and / or a thermoplastic polymer mainly composed of polylactic acid as the polymer used for the constituent fibers of the non-woven fabric for molding having biodegradability. Compared with the case where the above-mentioned polycaprolactone, polybutylene succinate, polyethylene succinate, etc. are used as the polymer having degradability, not only the crystallization is quick and the spinnability is good but also the advantage that the heat stability is excellent. Obtainable.

The number average molecular weight of the polylactic acid and / or the thermoplastic polymer mainly composed of polylactic acid is preferably 10,000 or more and 150,000 or less. More preferably 300
It is not less than 00 and not more than 120,000. If it is 10,000 or less, sufficient strength as a fiber cannot be obtained. Also 1500
If it exceeds 00, the viscosity becomes high at the time of spinning, and the spinnability decreases.

The biodegradable fiber for constituting the nonwoven fabric is the above-mentioned polylactic acid and / or a thermoplastic polymer mainly composed of polylactic acid, and has a melting point of 100 ° C. or more and a birefringence of 0. It is a long fiber composed of those having a diameter of 0.015 or less. This fiber is a high elongation fiber having an elongation of 100% or more.

[0013] In order to carry out thermal bonding to produce a nonwoven fabric using this fiber, and to maintain a certain strength after the thermal bonding, as described above, the melting point of this fiber is 100 ° C.
It is necessary to be above. Further, when a container-shaped product is formed by a nonwoven fabric, a certain degree of heat resistance is required. For example, the product may be softened in consideration of thermal stability because it passes through processing processes such as drying and molding processes, and is stored at a temperature of about 80 ° C. in summer during the distribution stage of the product. In order to prevent the possibility of deformation, the melting point of the fiber should be at least 100.
° C is required.

The birefringence of the polymer forming the fiber is preferably low from the viewpoint of suppressing the orientation as much as possible. If the birefringence exceeds 0.015, the degree of molecular orientation in the axial direction of the constituent fibers becomes excessive, and it becomes impossible to respond to the stress at the time of forming into a non-woven fabric, so that deep drawing cannot be performed. There is a fear. On the other hand, the lower limit of the birefringence is preferably kept to about 0.001, and if not oriented at all, not only the adhesion occurs during spinning or the spinnability deteriorates, but also the nonwoven fabric is formed and processed. In some cases, a problem may occur in that the mold shrinks in a preheating step described later and molding cannot be performed. Therefore, the preferable range of the birefringence of the polymer is 0.001 to 0.012, the more preferable range is 0.003 to 0.010, and the most preferable range is 0.003 to 0.008.

This fiber must have a high elongation of at least 100%, and if it is less than 100%, it is difficult to perform thermal deformation and is not suitable for molding. 100% elongation of this fiber
In order to achieve the above, the fiber must have a birefringence of 0.001 to 0.015 as described above. Since the elongation of the fiber is 100% or more, the sum of the longitudinal elongation and the lateral elongation in a 90 ° C. atmosphere of the nonwoven fabric for molding made of the fiber can be 160% or more. In addition, a container-shaped product molded from this nonwoven fabric can be made favorable without molding irregularities.

The fibers of the present invention are most preferably long fibers, but may be either short fibers cut to a suitable length after mechanical crimping using these fibers or short cut cotton. It can be appropriately selected depending on the purpose. In this case, the long fiber can be applied to a long-fiber nonwoven fabric for molding described below, or can be used as a base fabric for molding after knitting the long fiber. Also,
Even when formed as short fibers, it is possible to develop a nonwoven fabric made of a needle-punched short fiber nonwoven fabric, a fluid entangled short fiber nonwoven fabric, an embossed nonwoven fabric, or the like as a base fabric for molding.

The fineness of the long fiber is preferably 30 denier or less, particularly preferably 15 denier or less. If the fineness exceeds 30 denier, the rigidity of the long fiber becomes high, the coarseness becomes strong, and it becomes difficult to use it for general-purpose applications. In addition, in the melt spinning step, it is not preferable because the cooling and solidification of the spun yarn is hindered.

Various additives such as a matting agent, a pigment, a light stabilizer, a heat stabilizer, an antioxidant, and a crystallization accelerator may be incorporated into the above-mentioned fiber, if necessary. You may add in the range which does not impair.

The biodegradable non-woven fabric according to the present invention comprises the above-mentioned long fibers as constituent fibers. In this long-fiber non-woven fabric, there is a fusion bonding between fibers. It is necessary that many areas are provided in a scattered manner.
In the fused area, the composite filaments are fused by softening or melting of the polymer by thermocompression bonding. The form of the fusion zone provided in a large number of scattered spots is round, elliptical, slit, cross, deciduous, triangular, trilobal, square, pentagonal, hexagonal, octagonal. , Rhombus, T type, well type,
Any form such as rectangular, four-leaf, five-leaf, six-leaf, eight-leaf, swastika, etc. can be adopted. A large number of the fusion areas provided in the form of scattered points are measured and indicated by the compression area ratio.

The compression area ratio is represented by the area of the fusion zone with respect to the entire area of the nonwoven fabric.
It is preferably about 50%. When the pressure-bonded area ratio is less than 3%, the flexibility of the nonwoven fabric is improved, but the strength of the nonwoven fabric is reduced, and when the nonwoven fabric is rubbed, fluff is easily generated, which causes a problem in practical use. . On the other hand, if the compression area ratio exceeds 50%, the nonwoven fabric itself becomes extremely hard, and the handleability deteriorates. Further, the stress at the time of molding increases, which may cause a problem from the viewpoint of moldability. Therefore, the compression area ratio is more preferably 4 to 40%. Since the nonwoven fabric is maintained in form by being fused at these point crimping portions, and since the other portions are not thermocompression bonded, the nonwoven fabric is easy to bend, good handling, spreadability and the like are imparted. is there. The size of one fusion zone is preferably about 0.1 to 2.0 mm ² .

The density of the crimping points is preferably from 6 to 150 / cm ² . When the number is less than 6 / cm ² , the flexibility of the nonwoven fabric is improved, but the strength of the nonwoven fabric is apt to decrease, and when the nonwoven fabric is rubbed, fluff is easily generated. Occurs. In addition, the density of the crimping point is 1
If it exceeds 50 / cm ² , the nonwoven fabric itself becomes extremely hard, and the handleability deteriorates. Therefore, it is more preferable that the density of the crimping portion is 8 to 120 pieces / cm ² .
Most preferably, the density of the crimping points is 10 to 100 / cm ² .

The sum of the elongation at break in the longitudinal direction and the elongation at break in the transverse direction when the nonwoven fabric for molding of the present invention is pulled in a dry heat atmosphere at 90 ° C. must be 160% or more. . This is because the extension of the base fabric at the time of molding the container-shaped article contributes to both the longitudinal direction and the lateral direction, and as a result, the sum thereof gives the quality of deep drawability. At the time of molding, the deep drawing ratio, that is, the depth of the molded product in the molding die /
This is because if the equivalent diameter exceeds 0.3, at least this value is required to be 160%. In order to make the sum of the breaking elongation in the longitudinal direction and the transverse direction 160% or more, it is necessary to constitute the nonwoven fabric with the fiber having the breaking elongation of 100% or more as described above.

According to the present invention, there is provided a long-fiber nonwoven fabric for molding, which can be molded so that the deep drawing ratio is 0.4 or more, preferably 0.5 or more, and most preferably 0.6 or more. It aims at a method. Therefore, in the nonwoven fabric of the present invention, the breaking elongation is set to 160% or more, preferably 180% or more, and most preferably 200% or more.

The area shrinkage when the nonwoven fabric for molding of the present invention is heat-treated in a dry heat atmosphere at 90 ° C. for 1 minute is preferably 5% or less. If this area shrinkage ratio is too large, the nonwoven fabric enters the width at the time of preheating immediately before molding a container-shaped product using this nonwoven fabric, or at the time of heating by a mold during molding, and matches the molding die. In this case, the problem that the molded product of the target cannot be obtained and the problem of quality control of the molded product are likely to occur.

The basis weight of the nonwoven fabric of the present invention is not particularly limited. The nonwoven fabric having a relatively low basis weight is suitable for a field that emphasizes air permeability and drainage, for example, a molded product for a drain filter or a drain net. On the other hand, nonwoven fabrics with a relatively high basis weight are used for planting pots, filters, shoulder pads, etc.
Can be used for a wide range of applications.

The container-shaped article of the present invention is formed into a container by press-molding the above-mentioned biodegradable nonwoven fabric for molding. It is preferable that the container-shaped article formed by the press molding has a flange portion and a container portion projecting in a three-dimensional direction from the flange portion.

Next, a method for producing the biodegradable high elongation fiber of the present invention, a biodegradable nonwoven fabric for molding, and a container-shaped article using the nonwoven fabric will be described. The nonwoven fabric for molding of the present invention may be manufactured by another method.

The biodegradable high elongation fiber of the present invention comprises:
It can be manufactured by melt-spinning according to a conventional method and heat-treating without stretching. The temperature of melt spinning depends on the molecular weight of the polymer, but is preferably 150 to 230 ° C. The heat treatment is preferably carried out at a temperature not lower than the glass transition temperature of the polymer and not higher than the melting point of 40 ° C. or lower, under the condition that the film is not relaxed and stretched. Then, after heat treatment and winding, a desired fiber can be produced.

Next, the method for producing the long-fiber nonwoven fabric for molding of the present invention will be described together with the detailed method for producing the biodegradable high elongation fiber. In order to manufacture this nonwoven fabric, a generally known spunbonding method by melt spinning can be applied. That is, first, polylactic acid and / or
Or a polymer made of a thermoplastic polymer mainly composed of polylactic acid and having a melting point of 100 ° C. or more,
After melt-weighing at 0 ° C., spinning is performed. In this case, a spinneret of a usual spinneret device can be used. Subsequently, the spun fiber is cooled and solidified by a spraying device, and furthermore, 35% by a take-up means such as air soccer.
It is pulled and spread at a speed of not more than 00 m / min.

In the present invention, when the fiber yarn is pulled by air soccer or the like, it is desirable that the spinning speed be as low as possible within a range in which yarn breakage does not occur. This is because by setting the spinning speed in this manner, the birefringence of the constituent fibers is reduced to 0.015 or less as described above, and preferably 0.1 to 0.5.
The range of 002 to 0.012 is intended to reduce the orientation of the fiber, that is, the crystallization, and to facilitate the thermal deformation from the viewpoint of the molding process.

The drawing speed at the time of drawing the fiber is set to 3500 m / min or less as described above,
0 m / min or less, more preferably 2800 m / min or less, and most preferably 2500 m / min or less. In addition, even if the towing speed is as low as about 1500 m / min, the fibers and the nonwoven fabric do not undergo thermal deterioration.

According to the present invention, the fiber yarn is drawn at a speed of 3500 m / min or less without performing sufficient drawing to obtain an elongation of 1%.
High elongation fibers of 00% or more can be produced. When the high elongation fiber is used as the final product, the treatment is completed only by the above-described steps. On the other hand, when manufacturing a long-fiber nonwoven fabric for molding, the obtained fiber yarn is deposited on a moving conveyor net to form a fiber web.

In the present invention, when producing a nonwoven fabric for molding, it is preferable that the long fibers are softened by a heat treatment after the formation of the web so that the fibers of the surface layer of the fibrous web are pseudo-bonded to each other. Subsequently, a thermocompression treatment is performed to fuse the fibers with each other by softening or melting the polymer of the long fiber, thereby providing a fused area in a scattered manner. Thereby, the fibrous web can be integrated and then wound up by a winder to produce a nonwoven fabric.

In the present invention, after the fiber web is formed, it is preferable that the fibers of the surface layer of the fiber web are quasi-adhered by softening the long fibers as described above, for the following reasons. is there. That is, as described above, the birefringence of the polymer is 0.015 or less, and therefore, the crystallization of the long fiber itself constituting the web has not progressed so much. When introduced into the thermocompression bonding process, the problem is that the shrinkage of the web and the large width of the web are generated, and the problem that only a poor quality nonwoven fabric is obtained is prevented. Further, by pseudo bonding the fibers of the web surface layer to each other, the web can be smoothly transferred from the conveyor net to the thermocompression bonding step, and the operability can be improved.

In order to satisfactorily simulate bonding between the fibers of the surface layer of the fiber web, the temperature condition is set to a temperature from 120 ° C. lower than the melting point of the polymer constituting the long fiber to 50 ° C. lower than the melting point. Range, and a linear pressure of 0.
It is preferable to apply a pressure of about 1 to 5 kg / cm.

Next, a fused area formed by softening or melting the polymer of the long fiber is formed on the fibrous web in a scattered manner. In this case, a known device such as a hot embossing machine or an ultrasonic welding machine generally used for a dry nonwoven fabric can be applied.

For example, when a hot embossing machine is used, the processing temperature is generally from 100 ° C. lower than the melting point of the heat bonding component, that is, the polymer, to 5 ° C. lower than the melting point of the polymer. The range up to the temperature can be suitably applied. If the temperature exceeds 5 ° C. lower than the melting point of the polymer, the texture of the nonwoven fabric becomes hard, the handling is poor, and the operability for forming the nonwoven fabric is likely to be reduced. In addition, workability during deep drawing tends to deteriorate. On the other hand, if the temperature is lower than the temperature which is lower by 100 ° C. than the melting point of the polymer, the web is less likely to be thermocompression-bonded, and the shape retention of the nonwoven fabric tends to be reduced. If the hot embossing temperature is low, the web is taken up by the engraving roll, making it difficult to produce a nonwoven fabric with good operability. As described above, the processing temperature is a temperature equal to or lower than the melting point, but the softening point of the polymer is within the range of the processing temperature, and moreover, the pressure is applied at the pressing point portion of the engraving roll, so that it is ensured. It is in a fused state.

In the production of a nonwoven fabric, the form of the point bonding, ie, the pattern, of the nonwoven fabric is important because it affects the strength, flexibility, and hand of the nonwoven fabric.
One point is the engraving area of the engraving roll and its shape. The standard of the engraving area can be indicated by the compression area ratio at the time of thermocompression, and the preferable range of the compression area ratio is as described above.

On the other hand, when forming the welding area in a scattered spot using an ultrasonic welding machine, a fibrous web is passed between an engraving roll and a support having an ultrasonic welding mechanism, and a frequency of 20 kHz is applied.
What is necessary is just to oscillate about the ultrasonic wave. When changing the welding state, the wavelength of the ultrasonic wave may be appropriately changed depending on the material used. As the linear pressure in this case, about 0.5 to 2 kg / cm may be used unlike the case of the hot embossing machine. Further, the compression area ratio is preferably 4 to 50%. This method of performing point crimping by ultrasonic welding is more preferable because fibers other than the point crimping portion are hardly affected by heat and the texture is not hardened.

In the present invention, a container-shaped product is obtained by press-molding the nonwoven fabric thus obtained. This container-shaped article is preferably configured to have a flange portion and a container portion projecting in a three-dimensional direction from the flange portion.

When manufacturing such a container-shaped product,
The above-mentioned nonwoven fabric for molding is first preheated, and then press-molded using a mold. By this preheating, the fibers that come into contact with each other are fused together, whereby the final molded product can be given wear resistance and water repellency. In addition, only the contact portion of the constituent fibers is fused, and no fusion occurs except at the contact portion, so that the final molded product can be provided with air permeability.

At the time of this preheating, by performing the treatment at a temperature not lower than the softening temperature of the fibers constituting the nonwoven fabric and not higher than the melting point thereof by 100 ° C., the fibers are fused well, and the subsequent molding is performed. Workability can be improved.

In press molding using a mold, the temperature of the mold is preferably not lower than the glass transition temperature of the polymer and not higher than 30 ° C. lower than its melting point. If the temperature of the mold is lower than the glass transition temperature of the polymer, press moldability tends to deteriorate, and it becomes difficult to perform required deep drawing. Conversely, when the temperature of the mold exceeds 50 ° C. lower than the melting point of the constituent fibers, the molded product adheres to the mold,
The releasability at the time of removing this molded product has been reduced,
After all, the press formability tends to deteriorate.

As described above, the birefringence of the long-fiber polymer constituting the nonwoven fabric as a material for press molding is set to 0.1.
By reducing the orientation of the fiber, that is, the crystallization, to 015 or less, it is easy to be thermally deformed during press molding, so that good moldability can be ensured. Further, by making the sum of the longitudinal elongation at break and the elongation at break in the transverse direction of the nonwoven fabric measured in an atmosphere of dry heat of 90 ° C. 160% or more, deep drawing can be performed well during press molding as described above. be able to.

Since the nonwoven fabric as a material is heated in the preheating stage and the press molding stage, a heat shrinkage stress is applied to the constituent fibers. For this reason, although the obtained container-shaped product is pressed, the eyes are well clogged, and there can be no extreme stretching point. Therefore, for example, when applied to a container for raising seedlings, good root cutting performance can be imparted.

[0046]

Next, the present invention will be specifically described based on examples. The measurement and evaluation of various characteristics in the following Examples and Comparative Examples were performed by the following methods.

(1) Melting point of polymer: The temperature at which the extreme value of the melting absorption curve measured at a heating rate of 20 ° C./min using a differential scanning calorimeter DSC-2 manufactured by Perkin Elmer Co., Ltd. is defined as the melting point. did.

(2) Birefringence of polymer: Interfaco microscope manufactured by Carl Zeiss Jena Co., Ltd. Interfaco was used, and a liquid mixture of liquid paraffin and α-bromonaphthalene was used as an encapsulant. The fiber was divided into multiple layers in the radial direction in consideration of the thickness of the fiber, and the average value of the birefringence of all the layers was defined as the birefringence of the polymer.

(3) Elongation of fiber: Using Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd., according to JIS
It was measured according to L 1069.

(4) Strength and elongation of nonwoven fabric: Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd. was measured according to the strip method described in JIS L-1096. That is, a sample width of 5 cm and a sample length of 15
cm of the nonwoven fabric in the machine direction (MD) and the transverse direction (C).
10) each of the samples of D) were prepared,
It was measured at a tensile speed of 10 cm / min. The value obtained by averaging the maximum individual tensile strength in that case was defined as the tensile strength of the nonwoven fabric. The value obtained by averaging the elongation at break was defined as the tensile elongation of the nonwoven fabric.

(5) Compression area ratio: A small piece of the nonwoven fabric is enlarged and photographed with a scanning electron microscope, and the ratio of the total area of the point-compression-bonded portion to the area of the minimum repeating unit is individually set to 1
The crimping area ratio of the nonwoven fabric was measured by an average value obtained by measuring 0 times.

(6) Area shrinkage ratio of non-woven fabric in dry heat atmosphere: In a sample having a size of 1 m × 1 m, four frames each having a size of 5 cm in the vertical direction and 5 cm in the horizontal direction of the non-woven fabric. Described. Thereafter, the sample was placed on a sheet made of a tetrafluoroethylene resin, and treated using a hot air circulation type heat treatment machine at a heating temperature of 90 ° C. and a heat treatment time of 1 minute. After that, it was allowed to cool, the length of each frame was measured, the area after the hot water treatment was subtracted from the original area described first, and the ratio of the difference to the original area was calculated. The area shrinkage (%) was used. In addition, by averaging them, HWS
Indicated by

(7) Elongation at break under heating atmosphere: Tensile tester MODEL11 under heating atmosphere manufactured by Instron.
Measurement was performed according to the strip method described in JIS L-1096 using No. 22. That is, ten samples of the nonwoven fabric in the machine direction (MD) and the sample in the transverse direction (CD) each having a sample width of 5 cm and a sample length of 15 cm are prepared, and the gripping interval is 10
m, tensile speed 10 cm / min, internal atmospheric temperature 90 ° C.,
The measurement was performed at a temperature holding time of 1 minute. The elongation at break at that time was averaged to obtain the elongation at break of the nonwoven fabric.

(8) Abrasion resistance: length 20 cm × width 3 cm
Was prepared and measured using a friction tester (Gakushin type). That is, using cotton cloth No. 3 of JIS L-0803 as a friction cloth, 100 reciprocations were performed with a load of 500 g. Thereafter, the change in the appearance of the test piece was determined according to the following criteria, and the wear resistance was evaluated.

Grade 3: No fluff at all Grade 2: Some fluff but not noticeable Grade 1: Fluff is noticeable

(9) Biodegradation performance: A sample piece was buried in the soil, taken out after one year, two years, and three years, and observed for its form. ：: The nonwoven fabric retained its shape until 2 years after the sample was buried, and collapsed after 3 years.

Δ: The shape of the nonwoven fabric was broken by two years after the embedding of the sample. D: The nonwoven fabric was retained even after 3 years from the embedding of the sample.

(10) Moldability: The nonwoven fabric held by the clamp is preheated for 10 seconds in an atmosphere at a temperature 30 ° C. higher than the melting point of the polymer component, and then immediately moved to a heating mold to perform press molding. went. The mold has an upper diameter of 50 mmφ, a lower diameter of 40 mmφ, a depth of 40 mm, and a radius of curvature of 3 at the bottom.
mm. The clearance with the plug is 0.5m
m, and the temperature of both the mold and the plug was kept at 70 ° C. After molding, cool down, take out the molded product, measure the depth,
The heat set rate was determined based on the ratio of the depth to the mold, and the determination was made based on the following criteria. Further, the appearance of the molded product was inspected, and the moldability was determined based on the following criteria.

Heat setting rate ：: Heat setting rate is 90% or more Δ: Heat setting rate is 70% or more and less than 90% ×: Heat setting rate is less than 70% Appearance inspection ：: No abnormality is observed in the molded product : Molded product is generally good △: Molded spots are somewhat unsatisfactory ×: Molded spots are conspicuous or have holes

Example 1 A melting point of 168 ° C., a number average molecular weight of about 70,000, and a melt index value (190 ° C.) of 12 g / 10 as measured by the recipe of ASTM-D-1238E.
After melting and weighing polylactic acid having a molar ratio of D-lactic acid / L-lactic acid of 1/99 at 210 ° C., a single-hole spinning device (temperature 210 ° C.) having a normal round hole is used. Spinning was performed at a discharge rate of 0.83 g / min.

Subsequently, the spun yarn was pulled at 2,500 m / min by air soccer through a cooling device, opened, deposited on a moving conveyor net, and a fiber web having a fineness of 3 denier was obtained. . The birefringence of this fiber is 0.01
1. Its elongation was 115%.

The fibrous web was brought into contact with a heated rotating roll (temperature: 70 ° C., linear pressure: 0.5 kg / cm) to pseudo-adhere the surface layer of the web. Then, the crimping area ratio is 15
%, Crimping area density 22 pieces / cm ² , crimping area 0.7
The above-mentioned fiber web was point-pressed with an ultrasonic fusing device equipped with an engraving roll of mm ² and a flat roll at a linear pressure of 2 kg / cm. Thereby, the basis weight is about 100 g /
It was prepared long-fiber nonwoven fabric of m ^2. In addition, the characteristics of the nonwoven fabric were measured as described above.

The nonwoven fabric was used as a base fabric for molding, and molding was performed under the above condition (10) to evaluate moldability. Table 1 shows the above results.

As is clear from Table 1, a long-fiber nonwoven fabric could be obtained in a stable operation state. The obtained nonwoven fabric has thermal stability and basic performance required for molding, has good moldability, and is suitable for deep drawing.

[0065]

[Table 1]

(Example 2) The single hole discharge amount during spinning was 1.1.
0 g / min and the spinning speed was 3300 m / min. And
Otherwise, a long-fiber nonwoven fabric was manufactured according to the same formulation as in Example 1, and the characteristics were measured. The obtained nonwoven fabric was used as a base fabric for molding, and molding was performed to evaluate moldability. Table 1 shows the results.

As is clear from Table 1, the obtained long-fiber nonwoven fabric has a relatively high birefringence of the polymer of the constituent fibers,
Since the elongation at break (MD + CD) in the heating atmosphere was in a slightly low state, the moldability tended to be slightly inferior. But,
It had operability and thermal stability, and had the basic performance required for molding.

(Example 3) The single hole discharge amount during spinning was 0.3
The spinning speed was 3 m / min and the spinning speed was 1000 m / min. And
Otherwise, the same formulation as in Example 1 was applied, and the single fiber fineness was 3
A denier fiber web was obtained. The birefringence of this single fiber was 0.003, and the elongation was 140%. Thus, a long-fiber nonwoven fabric having a basis weight of about 100 g / m ² was produced.

The non-woven fabric is used as a base fabric for molding,
Molding was performed to evaluate moldability. Table 1 shows the results.
Shown in As is clear from Table 1, the obtained nonwoven fabric for molding has a slightly low tensile elongation at room temperature, but has a high elongation at break (MD + CD) under a heating atmosphere, and thus has good moldability. It was suitable for deep drawing.

Example 4 The discharge amount of a single hole was 1.55 g /
The spinning speed was 2,000 m / min, the fineness of single yarn was 7 denier, and the processing temperature during hot embossing was 95 ° C. Other than that, a long-fiber nonwoven fabric having a basis weight of about 100 g / m ² was manufactured as the same formulation as in Example 1, and the characteristics were measured. In addition, the nonwoven fabric was used as a base fabric for molding, and molding was performed to evaluate moldability. Table 1 shows the results.

As is clear from Table 1, the obtained nonwoven fabric for molding had good moldability and was suitable for deep drawing.

(Example 5) The discharge amount of a single hole was 2.78 g /
The spinning speed was 2500 m / min, the fineness of single yarn was 10 denier, and the processing temperature during hot embossing was 90 ° C. Other than that, a long-fiber nonwoven fabric having a basis weight of about 100 g / m ² was manufactured as the same formulation as in Example 1, and the characteristics were measured. In addition, the nonwoven fabric was used as a base fabric for molding, and molding was performed to evaluate moldability. Table 1 shows the results.

As is clear from Table 1, the obtained non-woven fabric for molding had good moldability and was suitable for deep drawing.

Example 6 The melting point was 130 ° C., the number average molecular weight was about 70,000, and the melt index value (190 ° C.) measured with the ASTM-D-1238E formulation was 15 g / 10.
After melting and weighing polylactic acid having a molar ratio of D-lactic acid / L-lactic acid of 12/88 at 210 ° C., a single-hole spinning device having a round hole (temperature: 210 ° C.) is used. Spinning was performed at a discharge rate of 1.00 g / min and a spinning speed of 3000 m / min.

Then, a fiber web having a single fiber fineness of 3 denier was obtained in the same manner as in Example 1 except for the above. The birefringence of the fiber was 0.012. In addition, a long-fiber nonwoven fabric having a basis weight of about 100 g / m ² was produced from this nonwoven web.

Further, the nonwoven fabric was used as a base fabric for molding, and molding was performed to evaluate moldability. Table 1 shows the results. As is clear from Table 1, the obtained nonwoven fabric for molding has a slightly low tensile elongation at room temperature, but has a high elongation at break (MD + CD) under a heating atmosphere, and thus has good moldability. It was suitable for deep drawing.

(Comparative Example 1) The single hole discharge amount was 1.33 g /
Min, and the spinning speed was 4000 m / min. Other than that, a long-fiber nonwoven fabric having a basis weight of about 100 g / m ² was manufactured in the same formulation as in Example 1, and its characteristics were measured. In addition, the nonwoven fabric was used as a base fabric for molding, and molding was performed to evaluate moldability. Table 2 shows the results.

As is evident from Table 2, the obtained long-fiber nonwoven fabric has biodegradability and excellent ordinary mechanical properties, but has a too high birefringence, and thus has a tensile strength under a heating atmosphere. It had low elongation (MD + CD), was unsuitable as a nonwoven fabric for molding, and had poor moldability.

[0079]

[Table 2]

(Comparative Example 2) An ordinary melt extruder was applied, and the melting point was 256 ° C and the intrinsic viscosity was 0.70 (in a mixed solvent of phenol: tetrachloroethane = 1: 1 at 20 ° C).
Is measured at 290 ° C., and a single-type spinneret having a round hole (temperature: 2).
(90 ° C.) and spinning at a single hole discharge rate of 1.67 g / min. After that, air soccer through the cooling device
The fiber web was drawn at 000 m / min, opened, and deposited on a moving conveyor net to obtain a fiber web having a fineness of 3 denier. This fiber web was processed by a hot embossing machine consisting of an engraving roll having a compression area ratio of 15%, a compression part density of 22 pieces / cm ² , a compression part area of 0.7 mm ² , and a flat roll at a processing temperature of 230. C. and a point pressure of 40 kg / cm were applied to form a long-fiber nonwoven fabric having a basis weight of about 100 g / m ² . The characteristics of the nonwoven fabric were measured. further,
The non-woven fabric is used as a base fabric for molding,
The moldability was evaluated. Table 2 shows the results.

As is apparent from Table 2, the obtained long-fiber nonwoven fabric was a nonwoven fabric having no biodegradability because polyethylene terephthalate was used as the polymer forming the fibers. Further, although the usual mechanical properties were excellent, the tensile elongation (MD + CD) under a heating atmosphere was low due to too high a pulling speed, which was unsuitable as a nonwoven fabric for molding, and the moldability was extremely poor.

(Comparative Example 3) The discharge amount of a single hole was 0.83 g /
Min, the spinning speed was 2500 m / min, and the hot embossing temperature was 150 ° C. Except for this, a long-fiber nonwoven fabric having a basis weight of about 100 g / m ² was manufactured using the same formulation as in Comparative Example 2, and the characteristics were measured. In addition, the nonwoven fabric was used as a base fabric for molding, and molding was performed to evaluate moldability. Table 2 shows the results.

As is clear from Table 2, the obtained long-fiber nonwoven fabric was a nonwoven fabric having no biodegradability because polyethylene terephthalate was used as the polymer forming the fiber. Moreover, although the tensile elongation (MD + CD) under a heating atmosphere was high, the abrasion resistance was poor due to the high area shrinkage, which was unsuitable as a nonwoven fabric for molding, and the moldability was poor.

[0084]

According to the present invention, it is specified that the melting point of polylactic acid and a thermoplastic polymer mainly composed of polylactic acid is 100 ° C. or more, and the birefringence of this polymer is 0.015 or less. A non-woven fabric formed of fibers of the above-described type and provided with scattered spots in which partial heat-fused regions are fused by melting or softening between fibers is used as a base fabric for molding. Since the sum of the elongation at break in the longitudinal direction and the elongation at break in the transverse direction measured below is 160% or more, the deep drawability at low temperatures is good, and no thermal deterioration occurs. This molding nonwoven fabric has a wide range of temperature conditions associated with molding processing, the quality of molded products is extremely stable, there is no problem in operation in molding processing, and it has biodegradability for disposal after use. Is not a problem. In particular, since polylactic acid and / or a thermoplastic polymer mainly composed of polylactic acid are used as the polymer having biodegradability, spinning properties are better than other biodegradable resins, and heat stability is excellent. There is an advantage that. For this reason, it can be widely used for food-type containers, aerated and molded liquid containers for various living materials, various molded materials for automobile interiors, molded containers for raising seedlings, interior bedding materials, filters, and the like.

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Claims (9)

[Claims] 1. A fiber made of polylactic acid and / or a thermoplastic polymer mainly composed of polylactic acid is accumulated, and the polylactic acid and the thermoplastic polymer mainly composed of polylactic acid have a melting point of 100 ° C. or more. And a birefringence of 0.015 or less, a partial heat fusion region in which the fibers are fused or softened by fusion is provided in a scattered manner, and a longitudinal direction measured in an atmosphere of dry heat at 90 ° C. A biodegradable nonwoven fabric for molding, wherein the sum of the breaking elongation and the transverse breaking elongation is 160% or more. 2. The biodegradable non-woven fabric for molding according to claim 1, wherein the area shrinkage when heat-treated in a dry heat atmosphere at 90 ° C. for 1 minute is 5% or less. 3. Melt spinning using a polylactic acid and / or a thermoplastic polymer mainly composed of polylactic acid and having a melting point of 100 ° C. or more, and cooling and solidifying the obtained yarn;
Next, the yarn is pulled and opened at 3500 m / min or less,
A fibrous web made of a polymer having a birefringence of 0.015 or less is formed into a fibrous web, and thereafter, the constituent fibers are softened so that the fibers of the fibrous web are pseudo-bonded to each other, and subsequently, the fibers of the fibrous web are softened. Or a method for producing a biodegradable non-woven fabric for molding, wherein the fibrous web is integrated by forming, in a scattered manner, a fused area in which the fibers are partially heat-fused between the fibers. . 4. A container-shaped article formed by press-molding the nonwoven fabric for molding according to claim 1 or 2 into a container. 5. The container-shaped article according to claim 4, comprising a flange portion and a container portion projecting in a three-dimensional direction from the flange portion. 6. A container shape characterized by preheating the nonwoven fabric for molding according to claim 1 or 2 to soften constituent fibers, and thereafter press-molding the nonwoven fabric for molding with a heated mold. Product manufacturing method. 7. The method for producing a container-shaped article according to claim 6, wherein the preheating is performed at a temperature equal to or higher than the softening temperature of the constituent fibers and equal to or lower than 100 ° C. higher than the melting point of the constituent fibers. 8. The method according to claim 6, wherein the mold temperature is a temperature equal to or higher than the glass transition temperature of the polymer and equal to or lower than a temperature lower than the melting point by 30 ° C. and lower than the preheating temperature. Manufacturing method of container-shaped product. 9. A fiber made of polylactic acid and / or a thermoplastic polymer mainly composed of polylactic acid, wherein the polylactic acid and the thermoplastic polymer mainly composed of polylactic acid have a melting point of 10%.
A biodegradable, high elongation fiber having a birefringence of 0.015 or less, and the fiber has an elongation of 100% or more.