JP3275974B2 - Polyester-based low-shrink heat-bonded 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 low-shrink heat-bonded fiber used for bonding a fiber structure.

[0002]

BACKGROUND OF THE INVENTION Thermal bonding fibers are known. However, since the melting point of the adhesive component is low, when the film is stretched and heat-set at a high temperature, fusion occurs, so that it is difficult to reduce the shrinkage at 160 ° C. or more. For this reason, when the base fiber and the heat bonding fiber are mixed and spread and laminated to form a web, and then heat-bonded,
The heat bonding fibers shrink and the bonding fibers are localized, the bonding points are reduced, the bonding strength is reduced, and there is a problem that delamination occurs when a thick fiber structure is formed.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to provide a heat bonding fiber which can easily produce a fibrous structure which does not decrease the number of bonding points due to shrinkage of the heat bonding fiber and does not cause delamination. .

[0004]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have found that the object can be achieved by reducing the shrinkage of the core by oriented crystallization. The present invention has been reached. That is, in the present invention, the heat bonding component contains terephthalic acid as an acid component in an amount of 90 mol% or more, 1,4 -butanediol and a polyalkylene diol are block copolymerized as a glycol component, and the copolymerization amount of the polyalkylene diol is increased. Is a polyester component having a sheath component of 30% by weight or more and 80% by weight or less and a non-elastomer polyester as a core component, and is drawn at a rate of 3000m / min to 5000m / min.
A core-sheath composite fiber obtained by orientation and crystallizing, wherein the difference in melting point between the core and the sheath is 40 ° C. or more, and the dry heat shrinkage at 160 ° C. of the composite fiber is 10% or less. It is a shrinkable heat bonding fiber.

Since the fiber of the present invention has a substantially core-in-sheath cross section made of a polyester elastomer having a sheath component as a heat bonding component in order to form a heat bonding fiber, most of the points of contact with the matrix fiber are thermally bonded. The adhesive component can be melted to an adhesive point. If the cross section is not substantially a core-in-sheath structure, most of the contact points with the matrix fibers cannot be used as adhesion points, so that the strength of the fiber structure is undesirably reduced.

[0006] The core component of the fiber of the present invention is a thermoplastic polymer, which melts and flows only the heat-adhesive component to form an adhesive point. The core component is not melted, and it is necessary to form a network structure connecting the matrix fibers. The purpose can be achieved by setting the melting point higher by at least 40 ° C. The heating temperature for the heat bonding is usually at least 20 ° C. higher than the melting point of the heat bonding component, so that the bonding point is formed by melting and flowing, so that the difference between the melting point of the core component and the melting point of the heat bonding component is 40. If the temperature is lower than 0 ° C., the core component is also softened and deformed at the time of thermal bonding, so that a network structure connecting the matrix fibers cannot be formed. The preferred melting point of the core component of the present invention can be thermoformed in a short time at a high temperature by increasing the melting point of the core component to 60 ° C. or higher. However, if the melting point is too high, the melt spinning temperature must be increased, resulting in thermal decomposition of the heat-adhesive component, resulting in degradation, and lowering the durability of the bonding point.
0 ° C. or less.

The fiber of the present invention has a dry heat shrinkage at 160 ° C. of 1
0% or less. When the dry heat shrinkage is 10% or less, the matrix fiber and the heat bonding fiber are mixed and then spread and laminated to form a web. Since the shrinkage is small even during heating and bonding, the mixed state is maintained and the three-dimensional network structure is maintained. Can be formed. Further, when the fiber structure once formed is further laminated and bonded and formed, the heat bonding component is present on the surface of the fiber structure, so that the heat bonding can be performed as it is. When the dry heat shrinkage exceeds 10%, the matrix fibers and the heat bonding fibers are mixed and then spread and laminated to form a web. When the fibers are heated and bonded, the heat bonding fibers shrink and the bonding fibers are localized and bonded. When the number of spots is reduced, the adhesive strength is reduced, or when a fibrous structure having a large thickness is formed, it is not preferable because a problem of delamination occurs. The preferred dry heat shrinkage of the present invention is 6% or less, more preferably 4% or less.

The core component of the fiber of the present invention is formed of a thermoplastic polymer, and is melt-spun at a high speed to orient and crystallize the core component to reduce the fiber shrinkage. In this regard, it is preferable to use a polymer having good crystallinity. In order to reduce the heat-shrinkable fiber by heat shrinkage, it is necessary to perform treatment at a temperature at which the heat-adhesive component softens and does not adhere. The shrinkage ratio is maintained by sufficiently maintaining the degree of orientation at a high temperature such as 160 ° C. It is difficult to lower. If the degree of orientation is not sufficiently maintained, the mechanical properties decrease, and when the matrix fiber and the heat bonding fiber are mixed and then spread and laminated to form a web, the heat bonding fiber is stretched and the shrinkage rate increases, When the heat-bonding fiber shrinks, the bonding fiber is localized, the bonding point is reduced, the bonding strength is reduced, and when a thick fiber structure is formed, it is not preferable because a problem of delamination occurs. In the present invention, the degree of orientation is sufficiently maintained by oriented crystallization and the mechanical properties are good, so that even when the fiber is opened, the heat-bonded fiber does not easily elongate, so that the shrinkage does not increase. Since the three-dimensional network structure thus formed has good mechanical properties, the fibrous structure also has good shape retention. As preferred mechanical properties of the fiber of the present invention, the initial tensile resistance after free treatment at 110 ° C. in dry heat is 15 g / denier or more, more preferably 20 g / denier or more.

The thermal adhesive component constituting the thermal adhesive fiber of the present invention has a copolymerization amount of 1,4-butanediol as a glycol component of 30% by weight or more and 80% by weight or less. In order to obtain an elastomer, it is necessary that a polyalkylene diol be block-copolymerized. As a result, even if the thermally bonded portion is deformed, it recovers when the elasticity is developed and the deformation force is released. The recoverability derived from the rubber elasticity is proportional to the copolymerization amount of the polyalkylene diol. At the same time, the melting point and heat resistance decrease. If the copolymerization amount of the polyalkylene diol is 30% by weight or less, the recoverability due to rubber elasticity is inferior. On the other hand, if the content is 80% by weight or more, the melting point is lowered and the heat resistance is deteriorated. Preferred copolymerization amount of the polyalkylene diol of the present invention is 40% by weight or more and 70% by weight or less,
More preferably, the content is 50% by weight or more and 60% by weight or less.
As the polyalkylene diol used in the present invention, known ones can be used, but polytetramethylene glycol is particularly preferable. The preferred average molecular weight is from 500 to 5,000, particularly preferably from 1,000 to 3,000.

[0010] The non-elastomer of the core component constituting the heat-bonding fiber of the present invention has a melting point of at least 160 ° C and can be oriented and crystallized by high-speed spinning. For example, polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, polyethylene It is a polyester with good crystallinity such as cyclohexylene dimethyl terephthalate. Particularly preferred is polyethylene terephthalate. Good crystallinity is less likely to be plastically deformed, so that workability is improved.

[0011] The core component and the sheath component are formed by known composite spinning.
Composite into a core-in-sheath type, and then 3000 m / min or more 500
It is taken at a speed of 0 m / min or less, and oriented and crystallized. In the orientation crystallization by spinning, the fiber surface is subjected to spinning tension during cooling, the molecular chains are oriented, and crystallization is promoted to near the glass transition temperature, so the fiber core becomes random amorphous. ,
Oriented crystallization of the core is usually difficult. But,
In the fiber of the present invention, since the sheath component is a polyester elastomer, most of the spinning tension is applied to the core, so that the orientation crystallization can be performed at a lower take-off speed than when spinning only the core component alone.

The thus obtained low-shrinkage oriented crystallized heat-bonded fiber is crimped, if necessary, and cut into staples. Alternatively, the fiber can be opened and expanded as it is to form a nonwoven fabric. Further, if necessary, it is preferable to perform a heat treatment at a temperature at which the core crystallizes below the fluid softening point of the thermal adhesive component. This is because, in a normal drawn yarn, the mechanical properties are reduced due to shrinkage due to heat treatment, but the fiber obtained by the preferred spinning method for obtaining the fiber of the present invention is oriented and crystallized. Can be increased, so that the mechanical properties are improved, and also during the processing step.
Furthermore, in the case of the eccentric core-sheath cross section, three-dimensional crimping occurs during thermoforming, and a three-dimensional network structure of a fiber structure can be formed by a helical coil. Can be given. Even a fibrous structure formed solely of the fiber of the present invention can provide softness and bulkiness and durability.

The denier of the heat-bonded fiber of the present invention is not particularly limited.
For example, 1 to 30 denier is preferable. Although the crimping of the heat-bonded fiber staple of the present invention is not particularly limited, it is preferable to use mechanical crimping which is excellent in blending and opening with matrix fibers. The cross section can be a round cross section, a deformed cross section, a hollow cross section, a deformed hollow cross section, or the like. It is preferable because it can be provided. When polyester is used as the matrix fiber as a preferred mode of use of the present invention, if the heat-bonding fiber is made of polyester, it can be regenerated without separation during recycling.

[0014]

The present invention will be described in detail below with reference to examples.

Example 1 453 parts of dimethyl terephthalate as an acid component and 1556 parts of 1-4 butanediol and polytetramethylene glycol as a glycol component were charged together with a small amount of a catalyst and a stabilizer. Polycondensation was performed under reduced pressure to produce a polyester ether block copolymer elastomer having a melting point of 158 ° C. The obtained polyester ether block copolymer elastomer was used as a sheath component, and polyethylene terephthalate having a melting point of 265 ° C. was used as a core component. The composite was compounded by a conventional method so that the sheath / core weight ratio was 50/50, and the spinning temperature was 280 ° C. , And spun at a take-up speed of 4000 m / min to obtain an undrawn yarn. still,
No eccentricity. Next, mechanical crimping is applied by a drawing crimper, and the mechanical crimp is supplied to a cutter with a tension that does not elongate, cut into 51 mm, and a 4-denier core component is oriented and crystallized, and the dry heat shrinkage at 160 ° C. is reduced. 4%, dry heat 110
A heat-bonded fiber having an initial tensile resistance of 28 g / denier after the treatment at ° C was prepared. The obtained heat-bonded fiber having mechanical crimp was 30% by weight and the glass transition temperature was 69 prepared by a conventional method.
A web obtained by obtaining 70% by weight of a PET short fiber having a three-dimensional crimp in a cross section having 13 denier hollow and three projections on the outside at a temperature of 100 ° C. in a good mixed-spreading state by using a card has a density of Compressed to 0.03 g / cc, forcibly penetrated by hot air at 180 ° C., heat-treated for 5 minutes, melted and flowed the thermal adhesive component, and joined at the amoeboid adhesive point where the intersection was bonded, and the adhesive point Formed a three-dimensional network structure uniformly dispersed therein, thereby obtaining a flat fiber structure having a density of 0.03 g / cc, in which delamination was difficult. The properties of the obtained fiber structure are as follows: 70 ° C. compression set is 22%;
%, The rebound resilience was 69%, and the 25% compression hardness was 28 Kg, showing a moderately high repulsion force, and suitable properties as a cushion material. In addition, 70 ° C compression residual strain,
Repeated compression set and rebound resilience at room temperature are JIS-K-6
401.

Comparative Example 1 The spinning temperature during spinning was 280 ° C., and the take-off speed was 1300.
m / min, and the heat-bonded fiber obtained in the same manner as in Example 1 except that it was stretched 3.4 times in a 50 ° C warm bath, had a dry heat shrinkage at 160 ° C of 24% and an initial tensile resistance of 32 g. / Denier, but became 17 g / denier after the dry heat treatment at 110 ° C. Using the obtained heat-bonded fiber, a fibrous structure was formed in the same manner as in Example 1. Thus, the heat-bonded fibers were significantly shrunk during thermoforming, the bonding points were unevenly dispersed, and the fiber structure was easily delaminated. The properties of the obtained fibrous structure are such that the compression set at 70 ° C. is 30% and the residual set at repeated compression is 10%. The rebound resilience was 63% and the 25% compression hardness was 23 kg.

Comparative Example 2 A heat-bonded fiber obtained in the same manner as in Comparative Example 1 except that heat treatment was performed at 90 ° C. after cutting, the dry heat shrinkage at 160 ° C. was 12%.
%, The initial tensile resistance was 20 g / denier at the beginning, but became 16 g / denier after the dry heat treatment at 110 ° C. Using the obtained heat-bonded fiber, a fibrous structure was formed in the same manner as in Example 1. Thus, the heat-bonded fiber had a low initial tensile resistance, so that the fiber structure was elongated at the time of fiber opening, significantly contracted at the time of thermoforming, the bonding points were unevenly dispersed, and the fiber structure was easily delaminated. The properties of the obtained fiber structure are 7
It is a fibrous structure that has poor compression set with a residual compression set of 0% at 34% and a residual compression set of 11%, and is difficult to use as a cushioning material.

Comparative Example 3 A side-by-side composite was prepared by setting the ratio of the heat bonding component to 30% by weight, and the ratio of the heat bonding component to the fiber surface was 1
The properties of the 4-denier heat-bonded fiber obtained in the same manner as in Example 1 except that it was set to 5% were as follows.
%, The initial tensile resistance after dry heat treatment at 110 ° C. is 30 g /
It was denier. A fibrous structure was prepared in the same manner as in Example 1 using the obtained heat-bonded fibers. At the time of thermoforming, the heat-bonded fiber exhibited crimping and formed a three-dimensional network structure in which a part was wound around the matrix fiber. However, most of the contact portions were not heat-bonded and remained at 70 ° C under compression. Fiber structure unsuitable as a cushioning material showing inferior settling resistance of 42%, repeated compression residual strain of 10%, rebound resilience of 49%, and 25% compression hardness of 9Kg showing only soft repulsion. was gotten.

Example 2 Distance L from center of fiber to center of core and radius R of fiber
(L + R) divided by RＲ (L + R) /
A 4-denier heat-bonded fiber prepared in the same manner as in Example 1 except that the eccentricity represented by R｝ was made to be 1.2, the dry heat shrinkage at 160 ° C. was 4%, and the dry heat The initial tensile resistance after the treatment at 110 ° C. was 27 g / denier. A fibrous structure was prepared in the same manner as in Example 1 using the obtained heat-bonded fibers. At the time of thermoforming, the heat-bonding fiber develops crimp and forms a three-dimensional network structure wound around the matrix fiber, and the contact portion has a form in which most of the heat-bonding is performed and the heat-bonding points are uniformly dispersed. Hard to delaminate, 24% compression set at 70 ° C, 5% compression set
%, Excellent in sag resistance, a rebound resilience of 64%, a 25% compression hardness of 20 kg, and a fiber structure suitable for a cushioning material exhibiting a slightly soft repulsion force.

[0020]

The heat-bonding fiber of the present invention has a low modulus and a high modulus at the same time as the shrinkage due to the orientational crystallization of the core component. In the case where the fiber structure was formed by blending and opening, the heat bonding points were uniformly dispersed, and the heat bonding fiber core had a higher modulus by heat treatment.
By forming a three-dimensional network structure, delamination is difficult,
A fiber structure having extremely excellent durability and cushioning properties can be easily obtained. Furthermore, when a latent crimping property is imparted as a preferred embodiment of the fiber of the present invention, it becomes possible to easily obtain a fiber structure imparted with softness and bulk and durability even when formed only from the fiber of the present invention. . It is particularly suitable for use in seats of automobiles, railways, ships, and the like. Furthermore, it becomes suitable for beds and furniture.
In addition to cushioning material applications, remarkably good crimping characteristics can impart elasticity, so it can be used for nonwoven fabrics that can be stretched regardless of low or high weighting, such as base fabrics, shoulder pads and bra cups, synthetic Leather base cloth or base cloth for napping cloth,
It can be widely applied to padding for safety materials, stretchable and breathable adhesive wadding layers for seats and adhesive nonwoven fabrics for interior materials. Furthermore, spinning is possible, and the present invention can be applied to uses for clothing such as spun yarn and decorative yarn.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-184119 (JP, A) JP-A-63-12746 (JP, A) JP-A-5-98516 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) D01F 8/14 D04H 1/54

Claims (1)

(57) [Claims] 1. A heat-bonding component contains terephthalic acid 90 mol% or more as the acid component, 1,4 as glycol component
- butanediol and polyalkylene diol is a block copolymer, and a copolymer of polyalkylene diol is 30 wt% or more, a polyester elastomer is 80 wt% or less as the sheath component, the non-elastomeric polyester used as the core component, 3000m / min or more 5000
A core-sheath composite fiber that has been drawn and oriented and crystallized at a rate of not more than m / min , and has a melting point difference between the core and the sheath of 40 ° C or more, and a dry heat shrinkage at 160 ° C of the composite fiber of 10% or less. A polyester-based low-shrink heat bonding fiber characterized by the following characteristics.