JP2018135622A - Heat-bonding conjugated fiber and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-bonding conjugated fiber suitable for use in a soft nonwoven fabric with excellent bulkiness, and a method for producing the same.SOLUTION: A heat-bonding conjugated fiber of the present invention is a bonding conjugated fiber characterized in that a core component is constituted of a polyester resin; a sheath component is constituted of a polyolefin resin; a structure has a concentric core-sheath shape in a fiber cross section orthogonal to a length direction of the fiber; a single fiber fineness is 1.0-10.0 dtex; a number of crimps is 10-20 mounts/25 mm; a crimping ratio is 10-25%; and a residual crimping ratio is 12-17%. The method for producing the heat-bonding conjugated fiber is characterized in that the bonding conjugated fiber of the present invention is produced by melt-spinning two components constituted of the core component made of the polyester resin and the sheath component made of the polyolefin resin so as to form a concentric core-sheath cross-sectional shape, obtaining an unstretched yarn, applying a heat-moisture steam such that a crimping tow temperature inside a stuffing box is 80-100°C during a crimping process after hot drawing, and fixing the crimps.SELECTED DRAWING: None

Description

  The present invention relates to a heat-adhesive conjugate fiber and a method for producing the same. More specifically, the present invention relates to a heat-adhesive conjugate fiber suitable for non-woven fabric applications that is soft and excellent in bulkiness, and a method for producing the same.

  Conventionally, a heat-adhesive conjugate fiber that can be formed by heat fusion using hot air or heat energy of a heating roll is easy to obtain a nonwoven fabric excellent in bulkiness and flexibility. It is widely used for sanitary materials such as pads, or industrial materials such as daily necessities and filters. In particular, sanitary materials are those that come into direct contact with human skin, and therefore the importance of bulkiness and flexibility is extremely high. In order to obtain bulkiness, a technique using a highly rigid resin or a technique using a fiber having a large fineness is representative, but in that case, the obtained nonwoven fabric has a reduced flexibility and physical irritation to the skin. Become stronger. On the other hand, when priority is given to flexibility in order to suppress irritation to the skin, the resulting non-woven fabric is significantly reduced in bulkiness, in particular, cushioning against body weight. For this reason, many methods have been proposed for obtaining fibers and nonwoven fabrics that are compatible with bulkiness and flexibility.

  Cited Document 1 proposes a core-sheath composite fiber in which the sheath component is made of polyolefin and the core component is made of polyester.

  However, by applying hot air heat treatment at a high temperature after crimping, the settling of the crimp increases, and the subsequent carding process also has a problem that sufficient bulkiness cannot be obtained by crimping. is there.

  Citation 2 proposes a cushioning material comprising a polyester component having a melting point of 200 ° C. or higher and a composite fiber serving as a polyether ester block copolymer component having a melting point of 180 ° C. or lower.

  However, the polyester ether elastomer, which is a polyether ester block copolymer, is a copolymer of a hard polyester and a soft ether, and since it contains a soft component, it has low heat resistance and is easily softened by heat. There is a problem that sufficient bulkiness cannot be obtained due to the crimping at the time of heat setting after application and heat processing in the production of the nonwoven fabric.

  Citation 3 proposes a composite fiber in which the sheath component is composed of a polyolefin resin and the core component is a polyester resin, and has an eccentric core-sheath structure in the fiber cross section.

  Cited Document 4 proposes a composite fiber in which the sheath component is made of polyolefin and the core component is made of a polytrimethylene terephthalate polymer, and the center of gravity of the core is shifted from the center of gravity of the fiber in the fiber cross section.

  However, in Cited Documents 3 and 4, since the fiber cross section is an eccentric core-sheath structure, the crimp becomes a three-dimensional crisp shape, the fiber opening property is inferior, and the workability with the card is reduced. There is a problem that the texture of the produced nonwoven fabric deteriorates.

JP 2000-336526 A JP-A-4-240219 JP 2014-234559 A JP 2003-3334 A

  Therefore, an object of the present invention is to solve the above-described problems in the prior art and provide a heat-adhesive conjugate fiber suitable for non-woven fabric applications that is soft and bulky, and a method for producing the same.

  In order to obtain a soft and bulky nonwoven fabric, the inventors of the present invention provide a crimping step after drawing the adhesive conjugate fiber, and simultaneously crimping the crimped tow by heating and heat treatment. By fixing, it was found that a heat-adhesive conjugate fiber in which crimping sag in the hot air drying process, the card process and the nonwoven fabric thermal processing, which is a conventional defect, was suppressed, was achieved, and the present invention was achieved.

  That is, the present invention aims to achieve the above object, and the heat-bonding conjugate fiber of the present invention comprises a polyester resin as a core component and a polyolefin resin as a sheath component, and is orthogonal to the length direction of the fiber. The cross-section of the fiber is a concentric core-sheath structure, the single fiber fineness is 1.0-10.0 dtex, the number of crimps is 10-20 crests / 25 mm, the crimp rate is 10-25%, and the residual The adhesive conjugate fiber is characterized in that the crimp rate is 12 to 17%.

  The adhesive conjugate fiber of the present invention is obtained by melt spinning two components having a polyester resin as a core component and a polyolefin resin as a sheath component so as to have a concentric circular core-sheath cross-sectional shape, obtaining an undrawn yarn, A method for producing a heat-bonding conjugate fiber, characterized in that, in the crimping step after stretching, a heated moist heat steam is applied so that the crimped tow temperature in the stuffing box is 80 to 100 ° C. and crimped. It is.

  The nonwoven fabric using the heat-bonding conjugate fiber of the present invention is soft and excellent in bulkiness, and is suitably used for sanitary materials such as diapers, napkins and pads, or industrial materials such as daily necessities and filters.

  Next, the embodiment of the thermobonding conjugate fiber and the manufacturing method thereof of the present invention will be specifically described.

  The heat-bonding conjugate fiber of the present invention is composed of two components in which the core component includes a polyester-based resin and the sheath component includes a polyolefin-based resin, and has a concentric core-sheath structure in a fiber cross section orthogonal to the fiber length direction. It is a heat-adhesive conjugate fiber.

  Polyethylene terephthalate is preferably used as the polyester resin constituting the core component of the thermoadhesive conjugate fiber of the present invention in consideration of raw material costs, thermal stability of the resulting fiber, and the like. Polyethylene terephthalate is a polyester obtained with terephthalic acid as the main acid component and ethylene glycol as the main glycol component, and may be a homopolymer, but 90 mol% or more is composed of ethylene terephthalate repeating units, It may be a copolymer containing a copolymerization component capable of forming another ester bond at a ratio of 10 mol% or less. Examples of the copolymerizable compound include dicarboxylic acids such as isophthalic acid, cyclohexanedicarboxylic acid, adipic acid, dimer acid, and sebacic acid, and the glycol component includes, for example, ethylene glycol, diethylene glycol, butane. Examples include diol, neopentyl glycol, cyclohexanedimethanol, polyethylene glycol, and polypropylene glycol.

  The intrinsic viscosity of polyethylene terephthalate is preferably 0.60 to 0.75. The intrinsic viscosity is more preferably 0.62 to 0.72. If the intrinsic viscosity is less than 0.6, the crimp retention rate of the fiber is lowered, and a fiber structure having sufficient bulkiness may not be obtained. On the other hand, if the intrinsic viscosity exceeds 0.75, the melt viscosity becomes high and it may be difficult to produce the fiber.

  In addition to the aromatic polyester containing an aromatic in the structural unit such as the polyethylene terephthalate, an aliphatic polyester can also be used, and preferable aliphatic polyester resins include polylactic acid and polybutylene succinate. .

  In order to impart functions such as sheerproofing and matting, inorganic particles may be added. Examples of the inorganic particles include silica sol, silica, alkyl-coated silica, alumina sol, titanium oxide, and calcium carbonate. The inorganic particles only need to be chemically stable when added to the polyester. Titanium dioxide is preferably used in terms of properties and costs. Although the density | concentration of an inorganic particle may be adjusted according to the function made into the target, 0.01-20.0 mass% is preferable with respect to the polyester fiber mass, and if it is 0.05-8.0 mass% It is more preferable from the viewpoint of yarn maneuverability, high-order processability, and fiber cost.

  Examples of the addition method include a method in which powder of inorganic fine particles is directly added to the core component and the sheath component, or a method in which inorganic fine particles are kneaded into a resin and added as a master batch. The resin used for masterbatch is most preferably the same resin as the core component and the sheath component, but is not particularly limited as long as it satisfies the requirements of the present invention, and a resin different from the core component and the sheath component is used. Also good.

  Polyolefin resins constituting the sheath subdivision of the present invention are polyethylene, polypropylene, polybutene-1, polyhexene-1, polyoctene-1, poly-4-methylpentene-1, polymethylpentene, 1,2-polybutadiene, 1,4. -Polybutadiene or the like can be used. These polymers may contain a small amount of α-olefin such as ethylene, propylene, butene-1, hexene-1, octene-1, or 4-methylpentene-1 as a copolymerization component.

  As the polyolefin resin used in the present invention, high-density polyethylene is preferably used. The melt mass flow rate of the high-density polyethylene is not particularly limited as long as it can be spun, but is preferably 8 to 25 g / 10 minutes, and more preferably 10 to 20 g / 10 minutes.

  The composite ratio of the heat-bonding fibers in which the core part of the present invention is a polyester resin (A) and the sheath part is a polyolefin resin (B) is (A) / (B) = 65/35 to 35/65 in mass ratio. Range. More preferably, the mass ratio is (A) / (B) = 55/45 to 45/55.

  When the core component exceeds 65% by mass, the mass% of the sheath component, which is a heat-adhesive component, decreases, and the adhesive strength of the nonwoven fabric decreases. On the contrary, when the sheath component exceeds 65% by mass, the mass component of the core component is reduced, which causes a problem in the mechanical strength of the nonwoven fabric.

  1.0-10.0 dtex is preferable and, as for the single fiber fineness of the heat bonding fiber of this invention, More preferably, it is 1.5-6.0 dtex. When the single fiber fineness is less than 1.0 dtex, since the fineness is small, the processability with the card is lowered, and the texture of the obtained nonwoven fabric is deteriorated. If it exceeds 10.0 dtex, the fineness increases, so that the rigidity of the fibers increases and the resulting nonwoven fabric becomes hard.

  The number of crimps of the heat-bonding fiber of the present invention is preferably 10-20 peaks / 25 mm, and more preferably 12-18 peaks / 25 mm. When the number of crimps is less than 10 crests / 25 mm, the entanglement of the fibers decreases, so that the processability with the card decreases and the texture of the obtained nonwoven fabric deteriorates. If it exceeds 20 crests / 25 mm, the fiber entanglement is strong, the fiber opening property is deteriorated, the workability with the card is lowered, and the texture of the obtained nonwoven fabric is deteriorated.

  The crimp rate of the thermal bonding fiber of the present invention is preferably 10 to 25%, and more preferably 14 to 20%. When the crimp rate is less than 10%, the fiber entanglement property is lowered, so that the processability with the card is lowered, and the texture of the obtained nonwoven fabric is deteriorated. If it exceeds 25%, the fiber entanglement is strong, the fiber opening property is deteriorated, the processability with the card is lowered, and the texture of the obtained nonwoven fabric is deteriorated.

  The residual crimp rate of the heat-bonded fiber of the present invention is preferably 12 to 17%, and more preferably 13 to 16%. If the residual crimp ratio is less than 12%, the crimping sag in the card process and the nonwoven fabric processing process becomes large, and sufficient bulkiness of the nonwoven fabric cannot be obtained. For fibers with a residual crimp rate of more than 17%, it is difficult to obtain a stable manufacturing method.

  The dry heat shrinkage ratio of the heat-bonded fiber of the present invention at 140 ° C. is preferably 0.3 to 3%, more preferably 0.5 to 2.5%. In order to obtain a fiber having a dry heat shrinkage rate of less than 0.3%, the drying temperature condition is increased. As a result, polyethylene is easily melt-bonded, and thus it is difficult to stably obtain the fiber. A fiber having a dry heat shrinkage rate exceeding 2.5% is inferior in dimensional stability of the nonwoven fabric in the heat bonding step, and a stable product cannot be obtained.

  Next, the manufacturing method of the heat-bonding conjugate fiber used in the present invention will be described by specifically illustrating one embodiment.

  The heat-bonded conjugate fiber of the present invention is obtained by melt-spinning two components having a polyester resin as a core component and a polyolefin resin as a sheath component so as to have a concentric circular core-sheath cross-sectional shape to obtain an undrawn yarn, In the crimping step after stretching, it can be produced by applying heated moist heat steam so that the crimped tow temperature in the stuffing box is 80 to 100 ° C. and crimping. This will be described in further detail below.

  First, a polyester resin and a polyolefin resin are melted, and a polymer is discharged from a die having a concentric core sheath. Through a spinneret having preferably 300 to 600 discharge holes, the spinning temperature is about 10 to 30 ° C. higher than the melting point of the polyester resin, and air at a temperature of 10 to 25 ° C. is preferably immediately after spinning, preferably 50 to 50 ° C. An undrawn yarn tow is obtained by cooling with an air flow of 100 m / min, applying a spinning oil agent, and preferably placing it in a can once at a take-up speed of 1000 to 1500 m / min.

  Subsequently, the obtained undrawn yarn tow is preferably drawn at a draw ratio of 2.0 to 4.0 times using a liquid bath at a temperature of 80 to 100 ° C., and then crimped by a stuffer box type crimper or the like. At the same time as applying crimp using a machine, heat-moisture heat treatment is performed so that the crimped tow in the stuffer box becomes 80-100 ° C. If it is less than 80 degreeC, crimp fixation will become inadequate and the crimp residual rate which is 12% or more will not be obtained. When the temperature exceeds 100 ° C., polyethylene melts and adheres in the stuffing box, making it difficult to stably obtain fibers. The crimped tow is heat-treated in a hot air atmosphere at 100 to 115 ° C. If it is less than 100 ° C., a dry heat shrinkage of 3% or less cannot be obtained. If the temperature exceeds 115 ° C., polyethylene melts and adheres, making it difficult to obtain fibers stably.

  The fiber heat-treated in the hot air atmosphere is cooled, and the fiber is cut into short fibers. Although it can select according to a use and it is not specifically limited, When performing a carding process, 30-76 mm is preferable, More preferably, it is 30-51 mm.

  The heat-adhesive conjugate fiber of the present invention includes, for example, absorbent articles such as diapers, napkins, and incontinence pads, medical hygiene materials such as gowns and garments, indoor sheets such as wall sheets, shoji paper, flooring, and cover cloths. , Life-related materials such as cleaning wipers, garbage covers, disposable toilets, toiletries such as toilet covers, pet items such as pet sheets, pet diapers, pet towels, wiping materials, filters, cushion materials, oil It can be used for various textile products that require bulkiness and compression resistance, such as adsorbents, industrial materials such as ink tank adsorbents, general medical materials, bedding materials, and nursing care products.

  Next, the thermoadhesive conjugate fiber of the present invention and the production method thereof will be described in detail with reference to examples. The measuring method of physical properties etc. is as follows.

(Intrinsic viscosity)
Weigh 2 g of sample, add 25 ml of orthochlorophenol, and dissolve with stirring for 70 minutes while heating at 102 ° C. After cooling, 15 ml is put into an Ostwald improved viscometer, and the intrinsic viscosity is calculated from the number of seconds dropped.

(Single fiber fineness, crimp number, crimp rate, residual crimp rate, dry heat shrinkage rate)
The measurement was performed according to JIS L1015 (2010).

(Composite ratio)
The cross section of the obtained thermal bonding fiber is photographed at a magnification of 400 times using a microscope, and the cross-sectional photograph is enlarged and copied. About the copied paper, the fiber part cross section was cut out, the mass was measured with N = 20 with the electronic balance, and it computed by averaging this.

[Example 1]
A heat-bonded conjugate fiber was produced by the following method. A polyester resin (A) having an intrinsic viscosity of 0.650 and a high-density polyethylene resin (B) having a melt mass flow rate of 18 are melted so as to have a mass ratio of (A) / (B) = 50/50, and discharged. After spinning through a concentric core-sheath die having 400 holes and cooling the spun yarn with air at a temperature of 20 ° C. at a flow rate of 60 m / min, an undrawn yarn tow was obtained at a take-up speed of 1000 m / min. .

  Next, the obtained undrawn yarn tow was subjected to one-stage drawing at a draw ratio of 3.0 times using a liquid bath at a temperature of 85 ° C., and crimped using a stuffing box type crimper. At the same time, heat-moisture heat treatment was performed so that the crimped tow temperature in the stuffer box was 90 ° C. Thereafter, the crimped tow was heat-treated in a hot air atmosphere at 110 ° C. and cut to a prescribed fiber length. The resulting heat-adhesive conjugate fiber has a single fiber fineness of 2.5 dtex, a crimp number of 14 ridges / 25 mm, a crimp rate of 18%, a dry heat shrinkage rate of 1.7%, and a crimped residual crimp rate of A physical property of 15% was obtained.

[Comparative Example 1]
A heat-bonding conjugate fiber was produced under the same conditions as in Example 1 except that the heat-moisture heat treatment in the stuffing box was not performed. The obtained heat-adhesive conjugate fiber has a single fiber fineness of 2.5 dtex, a number of crimps of 14 ridges / 25 mm, a crimp rate of 18%, a dry heat shrinkage rate of 1.7%, and a residual crimp rate of 10 A physical property of 5% was obtained.

[Comparative Example 2]
A heat-bonding conjugate fiber was produced under the same conditions as in Example 1 except that the heat and heat treatment in the stuffing box was 110 ° C. The obtained heat-adhesive conjugate fiber was a fiber bonded between the fibers.

Claims (2)

  The core component is made of a polyester-based resin, the sheath component is made of a polyolefin resin, and has a concentric core-sheath structure in a fiber cross section perpendicular to the fiber length direction, and the single fiber fineness is 1.0 to 10. An adhesive conjugate fiber having 0 dtex, a crimp number of 10 to 20 crests / 25 mm, a crimp rate of 10 to 25%, and a residual crimp rate of 12 to 17%.   In a crimp application step after heat drawing, melt spinning is performed so that the core component is a polyester-based resin and the sheath component is a polyolefin resin, and the two components are in a concentric circular core-sheath cross-sectional shape to obtain an undrawn yarn. A method for producing a heat-bonded conjugate fiber, in which heated moist heat steam is applied so that the crimped tow temperature in the stuffing box is 80 to 100 ° C., and crimped and fixed.