JP2001073228A - Heat bonding fiber and cushioning material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat bonding fiber excellent in high-temperature resistance to permanent set in fatigue and comfortableness and useful for a cushioning material, and the like, by exposing a polymer having a prescribed value or above of the glass transition temperature and the crystal melting point within a prescribed range to a part of the fiber surface. SOLUTION: This heat bonding fiber is obtained by exposing a polymer having >=50 deg.C, preferably >=60 deg.C glass transition temperature and 100-200 deg.C crystal melting point such as a copolyester to a part, e.g. 10-100% of the fiber surface. A base material fiber having >=75 deg.C glass transition temperature such as polyethylene terephthalate or polyethylene naphthalate is preferably joined with preferably 10-40 wt.% (in a cushioning material) of the heat bonding fiber to produce the cushioning material. The resistance to permanent set in fatigue of the cushioning material converted into an integral structure by thermoforming at 70 deg.C is preferably >=70%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat bonding fiber and a cushioning material using the same. For more information,
The present invention relates to a heat-bonding fiber in which a polymer constituting the heat-bonding fiber has unique thermal characteristics, and a cushioning material using the heat-bonding fiber in at least a part thereof. In particular, the present invention relates to a thermal bonding fiber and a cushioning material used for a cushioning material having high heat resistance and comfort for applications that are frequently exposed to high temperatures such as for vehicles.

[0002]

2. Description of the Related Art Up to now, polyurethane foam has been mainly used as a cushioning material. However, there is a problem in that it cannot be recycled, has poor air permeability, and has a problem in terms of comfort. In recent years, a fiber cushioning material mainly composed of polyester fiber has been proposed. Have been.

As a fiber cushion material, Japanese Patent Application Laid-Open No. 57-1
JP-A-01018, JP-A-58-31150, and the like have developed cushioning materials in which polyester fibers are melt-bonded. These cushioning materials use a low-melting adhesive component as an adhesive. For this reason, plastic deformation in an atmosphere of 40 ° C. or more is severe.
Under conditions and the like, high heat set resistance is remarkably inferior, and residual strain is low, so that it cannot be generally used for vehicles.

For the purpose of improving the high heat resistance of cushioning materials for vehicles, Japanese Patent Application Laid-Open No.
JP-A-247724 and JP-A-5-247819 propose a heat-bonding fiber and a cushioning material using a polyester elastomer for a sheath portion of a heat-bonding component having a core-sheath structure, but the heat resistance of the polyester elastomer is taken into consideration. Therefore, when exposed to a relatively high temperature atmosphere for a long period of time, there is a disadvantage that the bonded portion is deteriorated and the durability is deteriorated.

In Japanese Patent Application Laid-Open No. 6-200441, a polyester elastomer having improved heat resistance is used as a sheath of a heat-bonding fiber, and a thermoplastic polymer having a glass transition temperature of 65 ° C. or more is used as a base fiber. However, the glass transition temperature of the polyester elastomer itself is still low, and the high heat sag resistance was not sufficient.

Further, JP-A-6-165888 and JP-A-7-54253 disclose a glass transition temperature of 80 ° C.
As described above, the polyester fiber having a crystal melting point of 150 ° C. or more,
Polyester wool bonded with a copolyester-based heat-bonding fiber having a crystal melting point of 80 ° C. or higher is disclosed, but high heat set resistance was not sufficient.

On the other hand, by using a crystalline polymer having a low crystalline melting point as the polymer on the sheath side of the heat-bonding fiber, the texture is softened,
In addition, Japanese Patent Application Laid-Open No. 7-150455 discloses a polyester ball-shaped cotton which is hard to set when used in an atmosphere at a high temperature. In this publication, an ε-caprolactone copolymerized polyester binder fiber having a crystal melting point of 100 ° C. or higher is proposed as a heat bonding fiber. However, when ε-caprolactone is used as a copolymer component, it is preferable in that the melting point is lowered while maintaining high crystallinity, but the glass transition temperature is liable to be extremely lowered. Therefore, it is effective in the fields of bedding such as comforters and sleeping bags, quilting batting for cold weather clothing, cushioning materials, etc., which are aimed at in this publication, but vehicle cushions that require sag resistance at a high temperature of 70 ° C. It was hard to say that it was sufficient as a material for materials.

Therefore, in the prior art, even if a thermal bonding fiber and a cushioning material used in a normal atmosphere can be obtained, the cushioning material satisfying high heat sag resistance particularly in the field of vehicle cushioning materials exposed to high temperatures. Could not be offered.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-bonding fiber and a cushioning material which cannot be achieved by the above-mentioned prior art and which are used for a cushioning material having high heat resistance and comfort. .

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the sag resistance is mainly controlled by the glass transition of a polymer exposed to a part of the heat bonding fiber. Temperature and the melting point of the crystals. That is, the heat bonding fiber of the present invention has a glass transition temperature of 50 ° C. or more,
A thermobonded fiber characterized in that a polymer having a crystal melting point of 100 ° C. or more and 200 ° C. or less is exposed on at least a part of the fiber surface.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The heat bonding fiber of the present invention is characterized in that a polymer having a glass transition temperature of 50 ° C. or more and a crystal melting point of 100 ° C. to 200 ° C. is exposed on at least a part of the fiber surface. Fiber.

[0013] The glass transition temperature of the polymer constituting the heat bonding fiber of the present invention must be 50 ° C or higher.
If the temperature is lower than 50 ° C., if the strain is applied in an atmosphere of 70 ° C., the adhesive point due to heat easily undergoes plastic deformation, so that the high heat sag resistance is remarkably poor, and the object of the present invention cannot be achieved. Further, the glass transition temperature is more preferably 60 ° C. or higher. Conversely, if the glass transition temperature exceeds 100 ° C. and becomes too high, the function as a heat-bonding fiber decreases, and when compression is applied, the bonding portion becomes brittle, and it is easily broken and permanent strain remains, which is preferable. Absent.

Further, it is necessary that the polymer constituting the heat bonding fiber of the present invention has a crystalline melting point of 100 ° C. or more and 200 ° C. or less. The crystalline polymer having a crystalline melting point in the present invention refers to a polymer having an exothermic crystallization peak and a peak of heat of fusion in DSC measurement. Further, the crystal melting point is a peak temperature of a heat of fusion peak in DSC measurement.

The polymer exposed on the surface of the heat-bonding fiber of the present invention may be a homopolymer or a copolymer. In the case of a copolymer, the polymer may be crystalline or amorphous depending on the type of the copolymer component and the copolymerization rate. Sex. However, the glass transition temperature is high as the polymer used as the heat bonding fiber,
In addition, the present inventors have found that a cushioning material having remarkably excellent heat resistance can be obtained even under a relatively high temperature atmosphere by using a highly crystalline polymer.

If the crystal melting point of the polymer used is less than 100 ° C., the sag resistance at 70 ° C. is poor.
A satisfactory material for a vehicle cushion cannot be obtained.
On the other hand, if the crystal melting point exceeds 200 ° C., it is necessary to set a high molding temperature when producing a molded article such as a cushioning material, and as a result, the base material fibers such as the cushioning material are softened and melted, resulting in high heat resistance. The brittleness decreases. In addition, the texture of the cushion material becomes hard, which is not preferable.

The heat-bonding fiber of the present invention requires that a polymer having specific thermal characteristics in a specific range is exposed on a part of the fiber surface.

The heat bonding fiber of the present invention is preferably used in the form of a single component fiber or a composite fiber.

As the cross-sectional shape of the conjugate fiber in the present invention, a side-by-side type, a core-sheath type (concentric, eccentric) or the like is used. In order to further strengthen the adhesion, a core-sheath type (concentric or eccentric) is preferable. When this core-sheath type (concentric or eccentric) is used, it is preferable that the polymer having the defined thermal properties of the present invention constitutes a sheath portion. When a side-by-side type is used, at least one or both of them are used. It is preferable that the polymer of the present invention is used for the component (1).

If the polymer is not exposed on a part of the surface of the heat-bonding fiber, it does not fuse with the base fiber even when heated during thermoforming, and cannot be formed as a cushion material, so that the function as the heat-bonding fiber is not exhibited. .

The proportion of the polymer exposed to the heat bonding surface at this time is preferably 10 to 100%, and most preferably 100% is exposed to the fiber surface. Also, at that time, if the composite ratio of the above-mentioned polymer that bonds the heat-bonding fibers to each other or the base fiber and the heat-bonding fiber is too small, the bonded portion is easily broken when compression is applied, and permanent distortion remains. It is not preferable. The composite ratio is preferably 10 to 90%, more preferably 40 to 6%.
0%. The heat-bonded fiber of the present invention can be cut into a desired fiber length after spinning in the form of a conjugate fiber or the like, followed by drawing and crimping.

The heat bonding fiber of the present invention can be favorably used as a fiber constituting a cushion material. The cushioning material of the present invention is composed of a base material fiber and a heat bonding fiber.

The polymer constituting the heat bonding fiber of the present invention is:
Terephthalic acid as a main acid component, and ethylene glycol, propylene glycol, 1,4-butanediol, tetramethylene glycol, cyclohexane-1,4-dimethanol, pentamethylene glycol, hexamethylene glycol, and an EO adduct of bisphenol S (BPS
—EO) is a polyester having at least one selected from the group consisting of a main glycol component, and may be copolymerized with the following components.

That is, examples of the copolymerization component include aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid;
Phthalic acid, isophthalic acid, aromatic dicarboxylic acids such as diphenyldicarboxylic acid, oxycarboxylic acids such as oxybenzoic acid, and / or diethylene glycol;
One or more copolymer components from glycols such as propylene glycol and polyethylene glycol, 5-sodium sulfoisophthalic acid, and an EO adduct of bisphenol A (BPA-EO) can be used.

In the present invention, when the above copolymerization component is copolymerized for the purpose of lowering the melting point, the arrangement of molecules is disturbed,
As the melting point decreases and the crystallinity decreases, the glass transition temperature also tends to decrease.Therefore, in order to obtain a polymer satisfying both the high glass transition temperature and the high crystallinity in the present invention, a large melting point is required. It is most preferred to choose 2,6-naphthalenedicarboxylic acid, a unique compound that causes a drop and increases the glass transition temperature. In the case of polyethylene glycol, if the number average molecular weight exceeds 10,000, the reactivity in polymer synthesis is significantly reduced, and the unreacted product becomes incompatible with the polyester and may significantly impair the spinnability. It is preferable to use those of 10,000 or less.

The polymer constituting the base fiber in the present invention is preferably polyethylene terephthalate (PET).
N) and polyesters having a high glass transition temperature such as copolymers thereof are often used.

The preferred content of the heat bonding fiber in the cushioning material of the present invention is from 10% by weight to 40% by weight, more preferably from 25% by weight to 35% by weight. When the content is less than 10% by weight, the three-dimensional network structure formed as a thermal bonding point in the cushion material is small, and when a strain is applied, physical deformation occurs, and the sag resistance, durability, and cushioning property are significantly reduced. It is not preferable because it will do. When the content exceeds 40% by weight, the number of heat bonding points increases. However, since the content of the base material fiber that provides sag resistance and durability with respect to deformation when strain is applied is less than 60%, resistance to settling with respect to deformation when strain is applied is provided. , And the durability tends to be remarkably reduced.

Since the heat-bonding fiber of the present invention has a high glass transition temperature and a high crystal melting point, it does not stick when mechanically crimped while being steam-treated with a crimper after drawing. It is possible to apply a mechanical crimp set by an excessive heat. In the present invention, by using the heat-bonding fiber to which the strong crimp is sufficiently imparted, the number of heat bonding points between the base fiber and the heat-bonding fiber is increased, and the bonding point can be further strengthened.

As described above, when the heat-bonding fiber of the present invention is used, the entire cushioning material has a three-dimensional coil spring-like mesh structure, so that the coil of each fiber is slightly changed in any direction. It can deform and absorb forces and strains and maintain high heat resistance.

The fiber length of the heat bonding fiber in the present invention may be 30 to 100 mm as a staple length.
Further, the single fiber fineness may be usually 1 to 20 denier. When the heat bonding fiber is a composite fiber such as a core-sheath type, for example, polyethylene terephthalate can be used for the core and the polymer of the present invention can be used for the sheath. In the present invention, the matrix fiber is polyethylene terephthalate (PET) having a glass transition temperature of 75 ° C. or higher.
It is preferable to use In order to obtain even higher heat set resistance, the glass transition temperature is preferably 80 ° C. or higher,
Polyethylene naphthalate (PEN) having a temperature of 00 ° C or higher
It is more preferable to use

The cushioning material of the present invention is composed of a base fiber and a heat-bonding fiber. These fibers are mixed at a certain mixing ratio, opened once with a carding machine, and then laminated with a web to have a certain density. This is a cushioning material that is formed into an integral structure by compressing into a heat-treating machine and hot-forming at 200 ° C. for 30 minutes in a heat treatment machine, and then cooling, and has a characteristic of 70% or more of set resistance at 70 ° C. Have. If it is less than 70%, when a load is applied in a high-temperature atmosphere such as in summer, the cushion material is easily set and the strain is not recovered, so that the intended effect of the present invention may not be sufficiently obtained.

The set resistance at 70 ° C. of the cushioning material of the present invention is preferably 70% or more, more preferably 85% or more, even more preferably 90% or more.

The density of the cushion material is not particularly limited, but is preferably in the range of 0.02 to 0.06 (g / cc).

The cushioning material of the present invention is often used particularly for vehicles which are exposed to high temperatures. It is mainly used as a cushioning material for seats of trains, automobiles and the like as a vehicle application, but is often used as a ceiling material, a dash insulator, a floor insulator and the like of an automobile as other applications.

[0035]

EXAMPLES Each characteristic value defined in the present invention was determined by the following method. (1) Glass transition temperature (Tg) Differential scanning calorimeter (DSC-
Using 7), it was determined by measuring at a temperature rise rate of 15 ° C./min under a nitrogen stream. (2) Crystal melting point (Tm) Differential scanning calorimeter (DSC-
Using 7), the temperature was measured at a heating rate of 15 ° C./min in a nitrogen stream, and the peak temperature of the heat of crystal fusion obtained was taken as the crystal melting point. (3) Set resistance at 70 ° C. A cubic (10 × 10
× 10cm) and cut into parallel plane plates (vertical x horizontal = 1)
(5 × 15 cm).

In the method of cutting out from the cushion material, judging from the fiber arrangement inside the cushion material, the direction in which the fibers are compressed at the time of molding the cushion is determined, and the direction in which the fibers are compressed is substantially parallel to one surface of the cube. Cut out so that it becomes.
However, when the thickness or the like is less than 10 cm, the cube is made to be 10 cm by stacking a plurality of sheets.

The compression in the set-off test is such that the web is compressed to a thickness of 50% under a surface direction having the same direction as the direction in which the web was compressed at the time of producing the molded body (the side surface is in a free state), In this state, after keeping it in a dry heat at 70 ° C. for 22 hours, it was released from the parallel flat plate to release the strain and stop the compressing action. Further, it was transferred to room temperature (about 30 ° C.) and left as it was for 1 day (24 hours) ) From the thickness li (cm) after standing (standing) and the original thickness before treatment (10 (cm)), it was determined by {(li / 10) x 100) (%). The thickness was measured in units of 0.1 cm, and the number n was 5. (4) Cushioning The texture (softness, elasticity) when 10 panelists press by hand is ranked very good (10 points),
Evaluation was made as good (8 points), normal (5 points), and poor (0 points). When the average point exceeded 8 points, the texture of the cushioning material was very good.
Four or more and less than seven points were evaluated as normal, and less than four points were evaluated as poor. Examples 1 to 3 and Comparative Examples 1 to 3 Dimethyl terephthalate (DMT) or dimethyl 2,6-naphthalenedicarboxylate (NDCM) or at least one selected from ε-caprolactone (ε-CL) as a main acid As a component, ethylene glycol (EG), butanediol (BG), and polyethylene glycol (PEG) having a molecular weight of 1000 are used as a glycol component at a certain ratio (for example, in Example 1, DMT 95 and N
DCM 5 and EG 50 and BG 5 as glycol components
(A ratio of 0) together with a small amount of a catalyst and a stabilizer, and subjected to a transesterification reaction. Then, polycondensation was performed by heating and depressurizing to obtain a polymer to be used for the sheath portion. . Glass transition temperature (T
g) and the crystal melting point (Tm) are shown in Table 1.

The polymer used for the sheath is melted at 260 ° C., and the polymer (polyethylene terephthalate; PET) used as the other component (core component) is melted at 290 ° C., and the composite ratio is usually 50/50 by weight. From the spinneret at a spinning temperature of 292 ° C. and wound at a speed of 1350 m / min. Subsequently, the unstretched yarn was combined, stretched in a 80 ° C. warm bath at a stretch ratio of 3.0, mechanically crimped, and then cut to 51 mm. Table 1 shows the properties of the obtained heat-bonded fibers.

Next, polyethylene terephthalate (PET) having a three-dimensional crimp with a hollow cross section of 6 denier and a fiber length of 64 mm was used as the base fiber, and the resulting heat-bonded fibers were mixed at a mixing ratio of 30%. After opening, the web was laminated to give a basis weight of 4000 g / m ² , compressed to a thickness of 10 cm, thermoformed with hot air at 200 ° C. for 30 minutes, and then cooled to obtain a cushion material. Table 1 shows the results of evaluating the cushioning material.

[0040]

[Table 1]

In Examples 1 to 3, cushion materials were produced by using heat-bonding fibers having the thermal characteristics specified by the present invention. These cushioning materials were extremely good in both cushioning property and 70 ° C. set resistance.

On the other hand, the cushioning materials using the heat-bonding fibers of Comparative Examples 1 and 2 have good cushioning properties but low settling resistance at 70 ° C. Although the sag resistance at 0 ° C. was good, it was inferior in cushioning property due to insufficient thermal adhesion. From the above results,
The cushioning material using the heat-bonding fiber having the heat property specified in the present invention has good cushioning property and set resistance at 70 ° C., but the heat-bonding fiber deviating from the heat property specified in the present invention is used. The cushioning material used does not satisfy both the cushioning property and the 70 ° C. set resistance. Examples 4 to 6 Polylactic acid chips having the compositions shown in Examples 4 to 6 in Table 2 were vacuum-dried at 60 ° C. for 48 hours, and the chips were melted at a melter temperature of 250 ° C. by a Brescher melter type spinning machine. The polymer (polyethylene terephthalate; PET) used as another component (core component) is melted at 290 ° C.
It was discharged from a spinneret at a spinning temperature of 292 ° C. from a normal spinning machine at a composite ratio = 50/50 weight ratio, and was wound at a speed of 1350 m / min. Subsequently, the obtained unstretched yarn was ligated, stretched in a 80 ° C. warm bath at a stretch ratio of 3.0, and subsequently a finishing oil was applied, and then mechanically crimped to 51 m.
m.

Next, using polyethylene terephthalate (PET) having a three-dimensional crimp with a hollow cross section of 6 denier and a fiber length of 64 mm as the base fiber, the heat-bonded fiber obtained above was mixed at a mixing ratio of 30%. After opening with a card, the web is laminated to a basis weight of 4000 g / m ² and a thickness of 10 cm.
And then thermoformed with hot air at 200 ° C for 30 minutes.
After cooling, a cushion material was obtained. Table 2 shows the results of evaluating the cushioning material.

[0044]

[Table 2]

In Examples 4 to 6, cushion materials were prepared by using heat bonding fibers having a glass transition temperature of 50 ° C. or more and a crystal melting point of 100 ° C. to 200 ° C. These cushioning materials had good cushioning properties and 70 ° C. set resistance. Particularly, at a high glass transition temperature (Example 4), the sag resistance at 70 ° C. tended to be good. Examples 7 to 9 Next, using the heat bonding fiber of Example 1 as the heat bonding fiber,
Polyethylene naphthalate (PE) having a three-dimensional crimp having a hollow cross section of 6 denier and a fiber length of 64 mm as a base material fiber
N) Two types of copolymerized polyethylene terephthalate short fibers (Example 7: DMT95 and DMA5 as acid components, ratio of EG100 as glycol component, Example 8; DMT100 as acid component, BPS- as glycol component)
Using EO10 and EG90), the obtained heat-bonded fibers were mixed at a mixing ratio of 30%, opened with a card, laminated with a web to a basis weight of 4000 g / m ² , compressed to a thickness of 10 cm, and heated to 200 ° C. And then cooled to obtain a cushion material. Table 2 shows the results of evaluating the cushioning material.

In Examples 7 to 9, cushion materials were produced using the heat-bonded fibers having the thermal characteristics specified by the present invention. These cushioning materials were extremely good in both cushioning property and 70 ° C. set resistance. In particular, it was found that the combination of the heat bonding fiber of the present invention and the base fiber having a high glass transition temperature significantly improved the settling resistance at 70 ° C.

From the above results, the cushioning material using the heat-bonding fiber having the thermal characteristics specified in the present invention has both good cushioning property and set resistance at 70 ° C. A cushioning material using a heat-bonding fiber deviating in thermal characteristics cannot satisfy both the cushioning property and the 70 ° C. set resistance.

[0048]

According to the present invention, a heat-bonding fiber and a heat-bonding fiber for use in a cushioning material having high heat set resistance and comfort, particularly for applications frequently exposed to high temperatures such as for vehicles. A cushion material using fibers at least in part is obtained. In particular, by using the heat bonding fiber of the present invention in combination with a preferable base material fiber, a cushion material having a set resistance of 70% or more at 70 ° C. can be obtained.

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Claims (4)

[Claims] 1. A heat-bonded fiber wherein a polymer having a glass transition temperature of 50 ° C. or more and a crystal melting point of 100 ° C. or more and 200 ° C. or less is exposed on at least a part of the fiber surface. 2. A cushion material comprising a base material fiber bonded by the heat bonding fiber according to claim 1. 3. The cushion material according to claim 2, wherein the glass transition temperature of the base fiber is 75 ° C. or higher. 4. The cushioning material according to claim 2, wherein the cushioning material is integrally formed by thermoforming, and has a sag resistance at 70 ° C. of 70% or more.