JP4298484B2 - Ball-shaped cotton - Google Patents

Description

  The present invention relates to a ball-shaped cotton that is suitably used for bedding, furniture cushion materials, seat cushion materials, and the like.

  2. Description of the Related Art Conventionally, it is well known to use ball-shaped cotton made of polyester fiber as a cushion base material for bedding, furniture cushion materials, seat cushion materials and the like. For example, Patent Document 1 proposes a fiber ball having an average size of 1 to 10 mm made of a polyester fiber shrunk in a spiral shape. Patent Document 2 discloses a ball-like cotton in which a polyester fiber having a latent crimping ability capable of expressing a fine spiral crimp is spot-bonded with a binder fiber containing a copolymer polyester having a crystal melting point of 100 ° C. or higher as a binder component. Proposed.

  However, most of the conventional synthetic fibers conventionally used, such as polyester fibers as described above, are made from precious fossil resources such as petroleum. Also, they are hardly decomposed in the natural environment, and disposal is a problem. Polylactic acid, on the other hand, is made from plant resources such as corn. Polylactic acid fibers made from polylactic acid are processed into various products, and finally carbon dioxide is produced in natural environments such as compost or soil. It is completely biodegradable and decomposes into water. Patent Document 3 proposes a latent crimpable composite short fiber in which two types of biodegradable polymers having different melting points are eccentrically joined.

JP 62-33856 A JP 09-228215 A Japanese Patent Laid-Open No. 06-212548

  In view of the above-mentioned present situation, the present invention is a ball-shaped cotton suitable for obtaining a cushion excellent in bulkiness, compression elasticity, and also in moisture absorption / release by the blowing method, and manufactured using this. When discarding the cushioning material, an object is to provide a ball-shaped cotton that can be converted into a substance existing in nature.

The present invention to attain the aforementioned object, the first aspect of the present invention, two kinds of polylactic acid with different melt flow rate value (however, the combination of two different polylactide melting point are excluded.) The two kinds of polylactic acid have a difference in melt flow rate value of 20 to 50 g / 10 minutes and a melt flow rate value of 20 to 30 g. / 10 min of polylactic and a melt flow rate value is constituted by a 50 to 70 g / 10 min of the polylactic acid, and wherein the polylactic acid complex fiber is have a three-dimensional coil spring-like three-dimensional crimps The gadget cotton is the gist. The gist of the second invention of the present invention is a ball-shaped cotton containing the polylactic acid composite fiber having the above-mentioned three-dimensional crimps and a water-absorbing fiber.

The ball-shaped cotton of the present invention contains a composite fiber made of biodegradable polylactic acid made from plant resources, and the form of this composite fiber has a three-dimensional coil spring-like three-dimensional crimp. Therefore, it is excellent in bulkiness and rebound resilience, and has an independent ball shape, so that it is suitable for the blowing method and can be suitably used for producing a cushioning material and the like. In addition, because biodegradable polylactic acid, a plant-derived raw material, is used, it is possible to save petroleum resources and reduce total carbon dioxide emissions, and convert it into a naturally occurring substance when discarded after use. It is possible to make it.

  Hereinafter, the present invention will be described in detail.

  The ball-shaped cotton of the present invention contains a polylactic acid composite fiber having a three-dimensional crimp made of specific polylactic acid. Examples of the polylactic acid constituting the polylactic acid composite fiber used in the present invention include poly (D-lactic acid), poly (L-lactic acid), a stereocomplex of poly (D-lactic acid) and poly (L-lactic acid), D- Copolymer of lactic acid and L-lactic acid, copolymer of D-lactic acid and hydroxycarboxylic acid, copolymer of L-lactic acid and hydroxycarboxylic acid, D-lactic acid or L-lactic acid and aliphatic dicarboxylic acid, and Examples thereof include copolymers with aliphatic diols and blends thereof. Specific examples of hydroxycarboxylic acid in the case of a copolymer of lactic acid and hydroxycarboxylic acid include glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxypentanoic acid, hydroxyheptanoic acid, hydroxyoctanoic acid and the like. Can be mentioned. Among these, it is preferable from the viewpoint of cost to use hydroxycaproic acid or glycolic acid. Examples of the aliphatic dicarboxylic acid and the aliphatic diol include sebacic acid, adipic acid, dodecanedioic acid, trimethylene glycol, 1,4-butanediol, 1,6-hexanediol, and the like. When lactic acid is copolymerized with other components, the lactic acid unit is preferably 80 mol% or more. If it is less than 80 mol%, the melting point becomes too low and heat drawing becomes difficult, and it may be difficult to obtain a high-strength fiber, and heat resistance and wear resistance may be lowered.

  In the polylactic acid, if necessary, for example, a heat stabilizer, a crystallization nucleating agent, a matting agent, a pigment, a light resistance agent, a weather resistance agent, a lubricant, an antioxidant, an antibacterial agent, a fragrance, a plasticizer, a dye, Surfactants, flame retardants, surface modifiers, various inorganic and organic electrolytes, and other similar additives can be added as long as the object of the present invention is not impaired.

  In addition, the compound selected from epoxy compounds, oxazoline compounds, oxazine compounds, aziridine compounds, carbodiimide compounds, etc. is added to polylactic acid, and the terminal carboxyl group and hydroxyl group of the polymer are blocked to improve the resistance to moisture and heat degradation. May be.

The polylactic acid composite fiber has steric crimps by being composed of two specific types of polylactic acid, and the two types of polylactic acid are composed of two types of polylactic acid having different melt flow rate values (however, , Except for combinations of two types of polylactic acids having different melting points) .

Is a different polylactic acid of main belt flow rate value, according to ASTM D-1238 method, temperature 210 ° C., using what 20 to 50 g / 10 min difference melt flow rate value measured under a load 2160 g, the melt are use polylactic acid flow rate value 20 to 30 g / 10 min, a composite fiber composed of a melt flow rate value 50 to 70 g / 10 min polylactic acid having a three-dimensional crimps. When main belt flow rate value is within this range, it is possible to obtain a fiber excellent in strength and wear resistance with good productivity.

As the two polylactic acid used in the present invention, it is preferable to select a high crystal property. That is, poly (L-lactic acid) or poly (D-lactic acid), which is a homopolymer of polylactic acid, has a melting point of about 180 ° C., and any component in the case of a copolymer of D-lactic acid and L-lactic acid. When the ratio is about 10 mol%, the melting point is about 130 ° C. Furthermore, when the proportion of any of the components is 18 mol% or more, the melting point is less than 120 ° C., the heat of fusion is less than 10 J / g, which is almost non-crystalline, making heat stretching difficult, There is a problem that it becomes difficult to obtain a strong fiber, and heat resistance and wear resistance may be lowered. A stereocomplex of poly (D-lactic acid) and poly (L-lactic acid) is preferable because it has a high melting point of 200 to 230 ° C. and can be dyed at high temperature.

To obtain a polylactic acid composite fibers used in the present invention, two kinds of polylactic acid with different melt flow rate value the combined may be appropriately composite spinning.

Polylactic acid composite fibers used in the present invention, such as eccentric core-sheath or side-by-side, there are two types of fibers eccentrically to join the polylactic acid with different melt flow rate value. By setting it as such a composite form, it can be set as the fiber which is excellent in the bulkiness which has a three-dimensional crimp, and is hardly sticky. Here, the three-dimensional crimp is a mode different from the two-dimensional mechanical crimp, and is a so-called three-dimensional coil spring-like crimp. Further, a form in which twist is added to a part of the coil spring-like crimp may be used. As the crimp characteristics of this fiber, it is desirable that the number of crimps measured by a method specified in JIS L1015 is 6 to 20 pieces / 25 mm, and the crimp rate is 10 to 25%. When the composite fiber has such crimp characteristics, a clean spherical fiber assembly (ball-shaped cotton) can be obtained without forming a string when the ball-shaped cotton described later is manufactured. That is, if the number of crimps is less than 6 pieces / 25 mm or the crimp rate is less than 10%, the crimps tend to be large and the obtained ball-shaped cotton tends to be loosened, while the number of crimps is 20 pieces / 25 mm. Or the crimp rate exceeds 25%, the crimps become fine and the fibers are less likely to get entangled, making it difficult to obtain the desired spherical ball-shaped cotton.

  The composite ratio of the two types of polylactic acid is preferably 20/80 to 80/20 in terms of mass ratio in consideration of spinning operability.

  The cross-sectional shape of the polylactic acid composite fiber is not particularly limited, and is not limited to a round cross section, and may be an ellipse, a rhombus, a T-shape, a well-shape, a triangle, or a polygon more than that, and the outer shape is any of these The cross section may be a hollow cross section. In the case of a hollow fiber, a particularly good bulkiness is obtained, which is more preferable.

  Although the single yarn fineness of the polylactic acid composite fiber used for this invention is not specifically limited, It is set as the range of 1-100 decitex. When the single yarn fineness is less than 1 dtex, the fiber production efficiency is low and the cost is high. On the other hand, when it exceeds 100 dtex, it is difficult to cool with a normal spinning device, and special equipment is required.

  Furthermore, by adding a silicone-based oil to the polylactic acid composite fiber used in the present invention, it is possible to obtain a ball shape cotton having a very good shape close to a true sphere, and the ball cottons stick to each other. This is preferable because it is difficult and more independent. Moreover, since the softness of ball-shaped cotton is also improved, a soft and soft cushion body can be obtained. Examples of such silicone oils include dimethylpolysiloxane, diphenylpolysiloxane, methylphenylpolysiloxane, polyether-modified silicone oil, and higher alkoxy-modified silicone oil.

The manufacturing method of the polylactic acid composite fiber used for this invention is demonstrated. Two kinds of polylactic acid with different main belt flow rate value, and melt-spun using a conventional eccentric core-sheath or side-by-side composite spinning apparatus, taking over once without stretching hundreds of thousands an undrawn yarn - two million dtex Focus on the tow. This is heat-stretched and then relaxed to develop a coil spring-like three-dimensional crimp. In addition, the composite fiber that has been relaxed to develop the three-dimensional crimp is further heat set (at 100 ° C. or higher) in a state where no tension is applied, so that a coil spring-shaped three-dimensional crimp is developed and heat-fixed. Then, it is preferably cut to 15 to 76 mm, more preferably 20 to 38 mm to obtain short fibers.

  In the second invention of the present invention, the water-absorbing fiber used in combination with the polylactic acid composite fiber is natural fiber such as cotton, silk, wool, rayon, solvent-spun cellulose fiber, vinylon, recycled fiber, synthetic fiber, etc. A fiber that has an official moisture content of about 5% or more and is relatively easy to absorb water, or a polyacrylic acid-based superabsorbent fiber that can absorb water several tens to one hundred times more than its own weight. . Specific examples of the polyacrylic acid-based superabsorbent fibers include “Lanseer (registered trademark) manufactured by Toyobo Co., Ltd.” and “Bel Oasis (registered trademark manufactured by Kanebo Co., Ltd.)”.

  Among these hygroscopic fibers, solvent-spun cellulose fibers are more preferable because they are materials corresponding to environmental problems and have excellent humidity control performance as a cushioning material. The solvent-spun cellulose fiber will be described. Solvent-spun cellulose fiber is the main raw material pulp that is physically dissolved in the auxiliary raw material amine oxide solvent (which is used repeatedly in a closed system so as not to pollute the environment), and the cellulose fiber is not divided as much as possible. Manufactured by an epoch-making manufacturing method that turns into fiber. Therefore, compared with existing cellulosic fibers, for example, rayon produced by the viscose method, the wet and dry strength is high and the fiber shrinkage is low. In addition, it has the characteristics of being soft and soft to the touch, and excellent in hygroscopicity and water diffusibility.

  Polylactic acid fiber has an equilibrium moisture content of about 0.5% and almost no water absorption. Therefore, polylactic acid fiber has the disadvantage of poor water absorption and diffusibility when sweated, but water absorption such as solvent-spun cellulose fiber. By using the synthetic fiber in combination, this drawback can be effectively compensated, and the comfort when used as a bedding or a cushioning material is remarkably improved.

  The single yarn fineness of water-absorbing fibers such as solvent-spun cellulose fibers is not particularly limited, but generally those having 1 to 15 dtex are used.

  The manufacturing method of the ball-shaped cotton of this invention is demonstrated. First, the polylactic acid composite fiber cut into 15 to 76 mm, more preferably 20 to 38 mm, and more preferably, the water-absorbing fiber as needed, is stirred for 30 seconds to 10 minutes under a high-speed air current to have a diameter of about 2 to 20 mm. A soft ball-shaped cotton having a spherical shape can be obtained.

  The ball-shaped cotton thus obtained can be smoothly put by a so-called blowing method in which it is blown together with compressed air into a side cloth sewn into a shape such as a pillow, a cushion, a comforter, or a sleeping bag.

  Also, 10-40% by mass of a so-called binder fiber in which low melting point polylactic acid is arranged substantially concentrically in the sheath part, and high melting point polylactic acid such as polylactic acid homopolymer or polylactic acid stereocomplex polymer. It is also possible to make a ball-shaped cotton by mixing to some extent. In this case, each polymer of a polylactic acid composite fiber having a three-dimensional crimp that is the main component of the polylactic acid above the melting point of the polylactic acid in the sheath portion of the binder fiber after blowing ball-shaped cotton into a certain formwork or side surface. It is also possible to retain the mold in a specific shape by heat treatment at a temperature lower than the melting point. When heating in the mold, using a so-called suction type heat treatment machine in which hot air is blown from one side and sucked from the other side requires less heating time and is efficient. Further, after being heated in the mold, it may be formed into a predetermined shape by hot pressing or cold pressing.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by these. In addition, the evaluation methods of various physical properties described in the examples are as follows.
(1) Melt flow rate value of polylactic acid (g / 10 min)
The measurement was performed according to the method described in ASTM D-1238. The measurement conditions were a temperature of 210 ° C. and a load of 2160 g.

(2) Melting point (° C) and heat of fusion (J / g)
A differential scanning calorimeter DSC-2 manufactured by Perkin Elmer was used, and the measurement was performed under the condition of a heating rate of 20 ° C./min.

(3) High elongation of short fibers JIS L1015 was measured by a standard time test at a grip interval of 20 mm and a tensile speed of 20 mm / min.

(4) Bulkiness of ball-shaped cotton 5 g of ball-shaped cotton is gradually added to a 1000 cm ³ graduated cylinder, and after the charging, it is turned upside down five times. Then, lightly place a pressing plate (almost the same shape as the inner diameter of the graduated cylinder) on the ball-shaped cotton that can move smoothly in a horizontal state along the inner wall of the graduated cylinder with a mass per unit area of 0.5 g / cm ² . The volume occupied by the ball-shaped cotton is measured to determine bulkiness (cm ³ / g).

(5) Compression Elasticity of Ball-shaped Cotton 20 g of ball-shaped cotton was blown with compressed air into a mini-futon side fabric sewn 20 cm square to a thickness of 2 cm, and the blowing port was closed by sewing to create a mini-futon. Using this, 50% compressive stress (force required to reach 50% of the original thickness) was measured according to JIS K6401, and used as a measure of compression elasticity.

Example 1
Melting point 170 ° C., heat of fusion 38 J / g, optical purity 98.5% (mainly L isomer: controlled by charge ratio of L and D isomers when polymerized using lactide as raw material) A polylactic acid (hereinafter abbreviated as PLA1) chip with a melting point of 170 ° C., a melting heat of 45 J / g, an optical purity of 98.5%, and an MFR of 58 g / 10 min. After drying a chip of lactic acid (hereinafter abbreviated as PLA2) under reduced pressure, a composite melt spinning with a composite ratio (volume ratio) of 1/1 at a spinning temperature of 240 ° C. using a normal hollow side-by-side composite melt spinning apparatus did. The spun yarn was cooled with cooling air and then taken at a take-up speed of 1000 m / min to obtain an undrawn yarn. The obtained yarn is converged, made into a tow of 330,000 dtex, drawn at a draw ratio of 3.2 times, relaxed to develop a coil spring-like three-dimensional crimp, and then a higher alkyl phosphate ester K salt, ester 0.2% of a finishing oil mixed with nonionic ether and nonionic ether was added. Thereafter, the mixture was heat-treated with a 120 ° C. dryer and heat-set for drying and crimping, and then cut to a length of 32 mm. The obtained short fibers had a single yarn fineness of 6.6 dtex, a strength of 3.3 cN / dtex, an elongation of 64%, a number of crimps of 10.5 pieces / 25 mm, and a crimp rate of 21.4%. Using the short fibers, a spiral cotton high-velocity airflowed container was stirred at room temperature for 5 minutes to obtain a ball-shaped cotton of the present invention. The obtained ball-shaped cotton has an average diameter of 5 mm, the ball-shaped shape is good and uniform in size, and the ball-shaped cotton has a bulkiness of 165 cm ³ / g and a compressive stress of 62.72 N. / 400 cm ² .

For reference, when the bulkiness of the short fiber (card web opened with a sample roller card) itself before being made into ball-shaped cotton is measured according to 5.2 specific volume (bulk height) of JIS L1097, it is 127 cm ^3. / G.

Further, when 50% compressive stress was measured according to JIS K6401, using the same card web, the compressive stress was 26.46 N / 400 cm ² , both of which were lower than the value of ball cotton.

Reference Example A hollow side-by-side type composite fiber made of polyethylene terephthalate instead of polylactic acid composite fiber (Unitika Fiber Co., Ltd. <H38F> single yarn fineness 6.6 dtex, fiber length 32 mm, crimped number 9.7 / 25 mm, crimped A ball-shaped cotton was obtained in the same manner as in Example 1 except that the rate was 22.3%. The diameter of the ball-shaped cotton was 5 mm on average, the bulkiness of the ball-shaped cotton was 166 cm ³ / g, and the compressive stress was 46.06 N / 400 cm ² .

  When Example 1 is compared with a reference example (ball-shaped cotton made of polyethylene terephthalate fiber), the fiber has the same form (single yarn fineness, fiber length, crimped form), but the polylactic acid fiber is interfiber The ball of the present invention made of polylactic acid composite fiber when the ball-shaped cotton is hard to be crushed when a load is applied or when a cushion body is obtained by packing ball-shaped cotton of a certain mass into a certain sized side fabric because of high friction. A cushion body made of cotton-like cotton (Example 1) had a higher compressive stress than a cushion body made of polyethylene terephthalate ball-like cotton (Reference Example), and a product without a feeling of bottoming could be obtained.

Example 2
Instead of the finishing oil used in Example 1, it was carried out in the same manner as in Example 1 except that a polyether-modified silicone oil and an amide type cation mixed finishing oil were used.

  The diameter of the obtained ball-shaped cotton was an average of 5 mm, and the ball-shaped shape was uniform and almost uniform in size. The texture of the ball-shaped cotton was smooth and could be called a so-called feather touch. Further, the slipperiness between the ball cottons was good, and the blowing could be performed very smoothly. Furthermore, even when the ball-shaped cotton inside the mini-futon created by the evaluation of the compression elasticity of the ball-shaped cotton was forcibly moved to one side, it was restored to its original shape simply by tapping the mini-futon.

This bulky cotton had a bulkiness of 166 cm ³ / g and a compressive stress of 35.28 N / 400 cm ² .

Example 3
Mixing 70% polylactic acid composite fiber to which silicone-based oil obtained in Example 2 was applied with solvent-spun cellulose fiber “Lenting Lyyocell” 6.6 dtex, 30 mm short fiber 30% cut length. It was used and stirred for 5 minutes at room temperature in a container in which a spiral high-speed airflow was flowing to obtain the ball-shaped cotton of the present invention. The diameter of the obtained ball-shaped cotton was an average of 5 mm, and the ball-shaped shape was uniform and almost uniform in size.

This bulky cotton had a bulkiness of 131 cm ³ / g and a compressive stress of 31.36 N / 400 cm ² .

Comparative Example 1
Ordinary melt spinning was performed using PLA 1 used in Example 1 to obtain an undrawn yarn composed of a single component of PLA 1. The obtained yarns were converged to form a tow of 330,000 dtex, drawn at a draw ratio of 3.2 times, heat set with a 120 ° C. heat drum, and mechanically crimped with a crimper. Thereafter, 0.2% of finishing oil mixed with higher alkyl phosphate ester K salt, ester type nonion and ether type nonion was applied, and then cut to a length of 32 mm. The obtained short fiber had a single yarn fineness of 6.8 dtex, a strength of 3.6 cN / dtex, an elongation of 67%, a number of crimps of 9.3 pieces / 25 mm, and a crimp rate of 8.7%. The short fiber was stirred for 5 minutes at room temperature in a container in which a spiral high-speed airflow was flowing, but the resulting product was shaped like a string of fibers gathered, and the ball intended by the present invention. No blow test was performed.

Claims (5)

2 kinds of the polylactic acid with different melt flow rate value (however, the combination of two different polylactide melting point are excluded.) A ball-shaped cotton containing polylactic acid composite fibers eccentrically to joining, the two The type of polylactic acid has a difference in melt flow rate value of 20 to 50 g / 10 min, and a polylactic acid having a melt flow rate value of 20 to 30 g / 10 min and a polylactic acid having a melt flow rate value of 50 to 70 g / 10 min. configured, beaded cotton, wherein the polylactic acid complex fiber is have a three-dimensional coil spring-like three-dimensional crimps. The ball-shaped cotton according to claim 1, wherein the polylactic acid composite fiber is a hollow fiber. The ball-shaped cotton according to claim 1 or 2, wherein the polylactic acid composite fiber is provided with a silicone-based oil. 2 kinds of the polylactic acid with different melt flow rate value (however, the combination of two different polylactide melting point are excluded.) In a ball-shaped cotton containing polylactic acid composite fibers and absorbent fibers eccentrically to join the The two types of polylactic acid have a difference in melt flow rate value of 20 to 50 g / 10 min, a polylactic acid having a melt flow rate value of 20 to 30 g / 10 min and a melt flow rate value of 50 to 70 g / 10 min. A ball-shaped cotton comprising polylactic acid, wherein the polylactic acid composite fiber has a three-dimensional coil spring-like three-dimensional crimp . The ball-shaped cotton according to claim 4, wherein the water-absorbing fiber is a solvent-spun cellulose fiber.