JP3304020B2 - Composite binder fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binder fiber which has a soft and stretchable nonwoven fabric or a urethane-like soft texture which can provide a cushioning material which is resistant to settling even after repeated compression. It is about.

[0002]

2. Description of the Related Art Conventionally, polyurethane foam has been mainly used as a cushioning material for furniture, such as sofas, chair backrests, cushions, cushions and automobile seats. However, polyurethane foam is
Problems have been pointed out from the standpoint of safety and environmental protection, such as the generation of nitrogen-containing toxic gas during combustion, or the destruction of the ozone layer in the upper atmosphere by CFCs used during production.

[0003] Therefore, as a material replacing the polyurethane foam, a material obtained by needling a synthetic fiber web or a synthetic fiber having a low melting point after mixing a main fiber having a high melting point or a high decomposition point with a synthetic fiber having a low melting point. Heat-bonded fiber as a binder component (for example,
JP-A-57-35047), etc.
It has been considered to use short-fiber nonwoven fabric having high bulk, so-called solid cotton. However, when the web was needling processed, a part of the fiber was easily dropped or scattered, and when the web was heat bonded, there was a problem in the adhesiveness and the softness of the hand. Therefore, in order to improve the adhesiveness, a polymer having a low melting point in the same system as the main fiber is used as the binder fiber.For example, in the case where the main fiber is a polyester fiber made of polyethylene terephthalate,
Copolymerized polyester polymer obtained by copolymerizing ethylene terephthalate unit with the third component to lower the melting point is used as the binder fiber (for example, No.19, 50-
56 pages, published in October, 1980). In many cases, the binder fiber composed of a single component has a problem in terms of strength in terms of spinnability and the ability to pass through processing steps such as cards, and in order to improve this point, a polymer of the main fiber is further used as a core component, Binder fibers (for example, Japanese Patent Publication No. 45-2345) obtained by composite spinning using a binder component as a sheath component are used. However, when a polymer having the same melting point as the main fiber and having a low melting point is used as the binder component, there remains a problem in terms of softness.

Further, in order to impart elasticity to the bonding point and to give softness to the feeling of solid cotton, a polyester elastomer is used as a binder component (for example, Japanese Patent Laid-Open No.
-240219) has been proposed. However, when attempting to produce a binder fiber containing a polyester elastomer in a sheath portion, the frictional resistance between the polyester elastomer and the metal is large, so that it is wound around a drawing roller in the fiber manufacturing process or clogged in a crimper, resulting in poor productivity. It is difficult to produce fibers with good productivity, such as poor card passing properties, and to produce short fiber nonwoven fabric in the web production process of short fiber nonwoven fabric. Further, even if an attempt is made to use a polyester elastomer fiber as a main fiber in order to obtain a highly stretchable nonwoven fabric, those having a satisfactory stretchability as a nonwoven fabric due to the same low productivity as the binder fiber described above are industrially used. Has not been obtained.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and solves the difficulty of producing binder fibers containing a polyester elastomer as a component. Stretchable non-woven fabric and soft texture that can be used in the fields of stretchable non-woven fabric, wadding and bedding for furniture, cushion material for automobile seats, mattresses, cushions, mats, etc. It is an object of the present invention to provide a binder fiber suitable for obtaining a new solid cotton or the like which has difficulty in maintaining a repulsive force even after repeated use.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to develop such a novel binder fiber, and have reached the present invention. That is, in the present invention, the core is a polyester elastomer, and the sheath has a melting point of 200 ° C. or less.
The gist of the present invention is a composite binder fiber characterized by being a low melting point polymer having no elastomer elasticity .

Hereinafter, the present invention will be described in detail. A polyester elastomer is disposed on the core of the binder fiber of the present invention. As the polyester elastomer, an ethylene terephthalate unit and / or a butylene terephthalate unit is used as a hard segment, and a considerable amount thereof is used.
Approximately 30 to 80% by weight of a polyalkylene glycol such as polyethylene glycol, polytetramethylene glycol or ε-caprolactone
Molar to 80 mole%, copolymerized as a soft segment, or further copolymerized with isophthalic acid, adipic acid, sebacic acid, ethylene glycol, 1,6-hexanediol, and the like. Here, the amount of these additional copolymer components is preferably 20 mol% or less based on the number of moles of the constituent components of the polyester.

[0008] The elastomer properties of the polyester elastomer used in the present invention are as follows: the elongation is 70-1000% when the polyester elastomer itself is used as a drawn yarn, and the elastic recovery rate at 50% elongation (up to the original length). (100% when recovering, 0% when not recovering at all) is preferably 80% or more, or the elastic recovery at 200% elongation is 70% or more. The melting point of the polyester elastomer is preferably 1
The temperature is at least 00 ° C, more preferably at least 130 ° C. When the melting point is less than 100 ° C., the material may be easily debris when used for a chair or an automobile seat exposed to a high-temperature atmosphere, for example, under the scorching sun.

In the sheath of the binder fiber of the present invention, a thermoplastic low melting point polymer having a melting point of 200 ° C. or less and having no elastomer elasticity is disposed. As the low melting point polymer,
For example, polyethylene, polypropylene, low-melting polyester, low-melting polyamide and the like can be mentioned. Of these, low-melting polyesters, especially polyethylene terephthalate, are copolymerized with one or more compounds selected from phthalic acid, isophthalic acid, sebacic acid, adipic acid, diethylene glycol, 1,4-butanediol, and the like. preferable. Particularly, polyethylene terephthalate / isophthalate having a melting point of 100 to 200 ° C is inexpensive and easy to handle, and is particularly preferable. The melting point of the low melting point polymer in the sheath is 20
If the temperature exceeds 0 ° C., the heat bonding processing temperature becomes too high, and a suitable heat treatment apparatus may not be provided, or the polyester elastomer of the core may be undesirably denatured.

The relationship between the melting point of the polyester elastomer at the core of the binder fiber of the present invention and the melting point of the low-melting polymer at the sheath is determined by the case where the melting point of the sheath is lower than the melting point of the core depending on the application or the properties required for the nonwoven fabric. , And can be set in any case where the core is lower.
In the composite binder fiber of the present invention, the ratio of the polyester elastomer at the core to the low-melting polymer at the sheath is 20/80.
It is preferable to set between 80 and 20. As a composite form of the two components, a so-called core-sheath type having one core portion and a sheath portion surrounding the periphery or a sea-island type having a plurality of core portions may be used. Further, the cross-sectional shape of the composite binder fiber of the present invention may be a round cross-section, an irregular cross-section such as a triangular cross-section or a cross-section. The fineness of the composite binder fiber of the present invention is not particularly limited since it may be determined according to the use of the nonwoven fabric or the characteristics of the fiber when blended, but 2 to 20 denier is suitable.

In order to produce a nonwoven fabric using the binder fiber of the present invention, the binder fiber alone, or the main fiber and the binder fiber are mixed at a ratio determined according to the use or required characteristics, and a carding machine or the like is used. After the web is formed by a dry method or a wet papermaking method, only the sheath of the binder fiber or the entire binder fiber is melted through a heat treatment apparatus, and the fibers are point-bonded. In this case, needling may be performed before the heat treatment.
When a nonwoven fabric is produced using only the binder fiber of the present invention, a binder fiber in which a polymer having a melting point lower than the melting point of the polyester elastomer in the core is disposed in the sheath is used.

In the case of producing a nonwoven fabric in which the main fiber and the binder fiber of the present invention are mixed, the main fiber is a polymer having a lower melting point than the melting point of the low melting point polymer in the sheath of the binder fiber or the polyester elastomer in the core. Synthetic fibers such as polyester fibers, nylon fibers, acrylic fibers, and polypropylene fibers having a high decomposition point, regenerated fibers such as rayon fibers, and natural fibers such as wool, cotton, and hemp can be used. Preferred are polyester fibers such as ethylene terephthalate units, butylene butylene terephthalate units or ethylene naphthalate, particularly those having ethylene-2,6-naphthalate unit as a main component, and polyethylene terephthalate is particularly preferred from the viewpoint of physical properties and economy. Fiber consisting of Preferred. In this case, the mixing ratio of the main fiber and the binder fiber is 90/10 to 30/70.
Is appropriate. As the heat treatment device, a hot air circulation dryer, a hot air once-through dryer, a suction drum dryer, a Yankee drum dryer, a heating roll, a hot embossing roll, etc. are used, and a treatment temperature and a treatment time are selected according to the melting point of the binder fiber. Should be performed.

[0013]

The binder fiber of the present invention is mainly composed of a binder fiber having a core polyester elastomer having a melting point higher than the melting point of the low-melting polymer in the sheath, and is used as a web. The sheath is lower than the melting point of the polyester elastomer in the core. When heat bonding is performed at a temperature higher than the melting point of the low melting point polymer, the polyester elastomer of the core remains in a fibrous state, and an elastic nonwoven fabric can be obtained.

Further, for such a binder fiber,
As a main fiber, a fiber having a melting point higher than or equal to the melting point of the polyester elastomer at the core of the binder fiber or a fiber having a decomposition point is mixed to form a web, and a web is formed between the melting point of the polyester elastomer at the core and the melting point of the low melting polymer at the sheath. When the heat bonding process is performed at the temperature, the main fiber is bonded through the polyester elastomer fiber which is hard but has a high elasticity at the bonding portion, so that a non-woven fabric which retains a good shape and is hard to set can be obtained. it can.

Further, as a main fiber, a fiber having a higher melting point or a higher decomposition point than the core and the sheath of the binder fiber of the present invention is mixed with the binder fiber of the present invention,
Non-woven fabric with a soft texture that is soft and durable when the web is heat-bonded at a temperature between the melting point of the binder fiber itself and the melting point or decomposition point of the main fiber, and the core and the sheath contribute to the melt bonding. Can be obtained. In this case, since the main fibers are point-bonded with the low-melting-point polymer and also point-bonded with the polyester elastomer having a high elasticity, the obtained nonwoven fabric has a soft feel, and has a point-bond even after repeated compression. Since the part expands and contracts, the joint part is hard to peel off. Therefore, the shape of the nonwoven fabric is favorably maintained, and it is difficult to set.

[0016]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. The methods for evaluating various physical properties described in the examples are as follows. (1) Relative viscosity Equal weight mixture of phenol and ethane tetrachloride as solvent,
The measurement was performed at a sample concentration of 0.5 g / dl and a temperature of 20 ° C. (2) Melting point The melting point of the polymer having a crystalline melting point was measured by using a differential scanning calorimeter DSC-2 manufactured by Perkin Elmer Co., Ltd.
It was measured at 0 ° C./min. (DSC Method) In addition, the melting point of an amorphous polymer having no crystalline melting point in the DSC method was measured by a visual method using a microscope equipped with a hot stage. Hereinafter, unless otherwise specified, the melting point is determined by the DSC method.

(3) Set resistance during repeated compression After measuring the thickness of the solid cotton, a test piece (10 cm × 10 cm) was sandwiched between parallel flat plates and subjected to a total load of 15 kg at 60 times per minute. The thickness after the repeated compression test of 50,000 times is measured, and the bulkiness retention C (%) is calculated by the following equation (1), and is used as a measure of the difficulty in setting. The larger the value of C, the more difficult it is to set.

[0018]

(Equation 1)

(4) Feeling The feeling was evaluated in the following three stages by a sensory test by 10 panelists. 1: Soft 2: Normal 3: Hard

Example 1 A random copolymerized polyester elastomer chip (relative viscosity 1.84, obtained by mixing 40 mol% of ethylene terephthalate units as a hard segment and 60 mol% of ε-caprolactone (ε-CL) as a soft segment.
A chip having a melting point of 184 ° C.) and a polyethylene terephthalate / isophthalate copolymerized polyester (relative viscosity: 1.38, melting point of 110 ° C. by visual inspection, molar ratio of terephthalic acid / isophthalic acid: 6/4) were dried under reduced pressure, and then dried under reduced pressure. Melting is performed using a melt spinning device, and a polyester elastomer is disposed in a core portion, and a polyethylene terephthalate / isophthalate copolymerized polyester is disposed in a sheath portion. The composite ratio (weight ratio) is 1: 1. 3 total discharges
Composite melt spinning was performed at 13 g / min. After cooling the spun yarn, it was drawn at a take-up speed of 1000 m / min to obtain an undrawn fiber yarn. The obtained yarns are bundled, made into a 100,000-denier tow, drawn at a draw ratio of 2.8 and a draw temperature of 60 ° C.
After crimping was performed using an indentation type crimper, it was cut to a length of 51 mm to obtain a core-sheath type composite binder fiber of the present invention having a single yarn fineness of 4 denier.

Polyester fiber composed of the obtained composite binder fiber and polyethylene terephthalate having a round non-hollow cross section (strength 4.9 g / d, elongation 54%, fineness 6 denier, cut length 51 mm, using a push-in crimper The number of machine crimps applied was 10 pcs / inch and the crimp rate was 22%).
The cotton was mixed at a weight ratio of 0:80, passed through a carding machine, and then laminated with a cross wrapper to obtain a web having a basis weight of 600 g / m ² .
Needling was performed at a needle density of 240 needles / cm ² through a needle locker room having a barbed needle. Further, this web was put between wire meshes with a spacer of 20 mm in thickness, and heat-treated for 5 minutes in a hot air circulating drier at 200 ° C. while controlling the thickness.
0 mm solid cotton was obtained.

Example 2 Polyester obtained by mixing 38 mol% of butylene terephthalate unit (PBT unit) as a hard segment and 62 mol% of ε-CL as a soft segment in place of the polyester elastomer chip used in Example 1. Elastomer chip (relative viscosity 1.97, melting point 16
0 ° C.) to obtain the composite binder fiber of the present invention. Furthermore, in Example 1, a round hollow conjugate type polyester fiber (strength 3.4 g / d, elongation 60%, fineness 13 denier, cut length 51 mm, three-dimensional crimp 10 crimps / Inch, crimp rate 18
%, Hollowness was 22%), and solid cotton was obtained in the same manner as in Example 1 except that the temperature at the time of heat treatment of the web was changed to 200 ° C. and 180 ° C.

Example 3 Instead of the polyester elastomer chip used in Example 1, 29 PBT units were used as hard segments.
Mol%, 71 mol% of ε-CL as a soft segment
The composite binder fiber of the present invention was obtained using a polyester elastomer chip (relative viscosity 2.07, melting point 137 ° C.) obtained by blending. Further, except that the heat treatment temperature of the web in Example 1 was set to 150 ° C. instead of 200 ° C.
Solid cotton was obtained in the same manner as in Example 1.

Example 4 In place of the polyester elastomer chip used in Example 1, 47 PBT units were used as hard segments.
Mol%, 53 mol% of ε-CL as a soft segment
The composite binder fiber of the present invention was obtained using a polyester elastomer chip (relative viscosity 2.09, melting point 180 ° C.) obtained by blending. Furthermore, solid cotton was obtained in the same manner as in Example 1.

Example 5 In place of the polyester elastomer chip used in Example 1, 56 PBT units were used as hard segments.
Mol%, 44 mol% of ε-CL as a soft segment
The composite binder fiber of the present invention was obtained using a polyester elastomer chip (relative viscosity 1.85, melting point 204 ° C.) obtained by blending. Furthermore, except that the heat treatment temperature of the web in Example 1 was set to 220 ° C. instead of 200 ° C.
Solid cotton was obtained in the same manner as in Example 1.

Example 6 Instead of the polyester elastomer chip used in Example 1, 45% by weight of butylene terephthalate unit (PBT unit) as a hard segment and 55% by weight of polytetramethylene glycol having a molecular weight of 600 as a soft segment were blended. Using the obtained polyester elastomer chip (relative viscosity 1.97, melting point 172 ° C.), the composite binder fiber of the present invention was obtained. Further, the temperature during the heat treatment of the web in Example 1 was changed to 200 ° C.
Solid cotton was obtained in the same manner as in Example 1 except that the temperature was changed to 5 ° C.

Comparative Example 1 In Example 1, composite melt spinning was performed using a polyester elastomer chip as a sheath and a polyethylene terephthalate / isophthalate copolymerized polyester chip as a core (core-sheath reversal). The undrawn yarn thus wound had fiber adhesion between the single fibers, and when stretched as it was, poor winding by a stretching roller and poor passage through a crimper were recognized, resulting in poor productivity. In this case, the production of solid cotton was stopped.

Comparative Example 2 In Example 1, a polyethylene terephthalate / isophthalate copolymerized polyester chip was used as a sheath, a normal polyethylene terephthalate chip (relative viscosity: 1.38, melting point: 255 ° C.) was used as a core, and the spinning temperature was 280 ° C. Except for the above, a composite binder fiber of a comparative example was obtained in the same manner as in Example 1. 150 ° C instead of 200 ° C
Solid cotton was obtained in the same manner as in Example 1 except that Table 1 shows the evaluation results of the densities, feeling, and sag resistance of the obtained solid cotton of Examples 1 to 6 and Comparative Example 2.

[0029]

[Table 1]

As is evident from Table 1, all of the solid cottons of Examples 1 to 6 had good feeling and set resistance, but the solid cotton of Comparative Example 2 had a slightly hard feel and resistance to heat. Rust was poor.

Example 7 100% of the core-sheath type composite binder fiber obtained in Example 1
After passing through a carding machine, a web having a basis weight of 60 g / m ² was formed and heat-treated in a hot air flow dryer at 165 ° C. for 30 seconds to obtain a nonwoven fabric. The obtained nonwoven fabric had elasticity and a soft feel because the core polyester elastomer remained in a fibrous state.

Example 8 In Example 7, the sheath was made of polyethylene (melting point: 130).
C)) to obtain a nonwoven fabric in the same manner as in Example 7, except that the composite binder fiber of the present invention was obtained. The obtained nonwoven fabric had elasticity and a soft feel because the core polyester elastomer remained in a fibrous state.

[0033]

By using the composite binder fiber of the present invention, a nonwoven fabric having a soft feel and a nonwoven fabric excellent in elasticity can be obtained. Also, when this is made into a solid cotton, it has a soft feeling of urethane-like, and is hard to be repeatedly compressed. Therefore, when used as a wadding, it has a soft touch and absorbs shock, so it is comfortable to sit on, has little settling over time, and if it has a certain thickness, there is no feeling of flooring. Suitable as cotton, bedding, cushioning material for automobile seats and mattresses.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-306708 (JP, A) JP-A-6-272111 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D01F 8/14

Claims (1)

(57) [Claims] 1. A composite binder fiber wherein the core is a polyester elastomer and the sheath is a low melting point polymer having a melting point of not higher than 200 ° C. and having no elastomeric elasticity .