JPH0551853A - Copolyester fiber laminate having shape memorizing ability - Google Patents

Abstract

PURPOSE:To obtain a fiber laminate having shape memorizing ability, providing nonwoven fabric or solid fibers returning to a shaped state by low level heating even in form collapse when binder fiber is fused to a high temperature and the fiber laminate is formed once. CONSTITUTION:A yarn laminate comprising copolyester fiber obtained by copolymerizing >=6C long-chain aliphatic dicarboxylic acid, having >=150 deg.C melting point and >=2.5g/denier single fiber strength and thermally fusible binder fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber laminate made of synthetic fibers, and more particularly to a copolyester fiber laminate which can be made of non-woven fabric having shape memory ability or cotton wool.

[0002]

2. Description of the Related Art In recent years, synthetic resins having shape memory ability have been developed and put on the market. This resin has a large change in elastic modulus before and after the glass transition point. The function is, for example, to first form an arbitrary shape A, heat in the state of the shape A and crystallize (entanglement of crystal parts) or intermolecular cross-linking to generate a fixed point and store the shape. Then, an external force is applied in an atmosphere having a glass transition temperature or higher and lower than the above heating temperature to deform into shape B, and the temperature is maintained below the glass transition point as it is, so that shape B can be fixed. By further heating this above the glass transition point, it has a function of recovering the shape A without applying an external force, that is, it has a "shape memory ability".

As a resin material having a shape memory ability, a polytransisoprene resin (Japanese Patent Laid-Open No. 55-93806) is used.
No.), polynorbornene-based resin (JP-A-59-5352)
No. 8), consisting of a mixture of vinyl resin and acrylic acid resin or synthetic rubber (JP-A-63-17952).
No.) etc. are known. Further, a polyurethane-based shape memory polymer yarn (Japanese Patent Laid-Open No. 2-169713) is disclosed.

However, most of the conventionally known resin materials have poor spinnability and rubber elasticity, and the fibers have low strength. Therefore, it was almost impossible to produce high-strength fibers above a certain level with high productivity. Also, after making short fibers,
For example, when trying to make a fiber laminate through a card machine, single fiber breakage occurs due to its low strength, and because of the rubber elasticity, so-called card sinking phenomenon in which fibers are entangled near the root of the card cloth is seen, It cannot be made into a laminate, and this fiber laminate is needle punched,
It was completely unthinkable to produce industrially useful non-woven fabric or cotton by heat treatment.

[0005]

The present invention is intended to solve such a problem. That is, the present invention intends to provide a fiber laminate using a copolyester having a shape-memory ability capable of melt-spinning a high-strength fiber with high productivity as in the case of a normal polyester.

[0006]

The present inventor has arrived at the present invention as a result of extensive studies to solve the above-mentioned problems.

That is, the first invention of the present application has a melting point of 15
A fiber laminate characterized by comprising a copolyester fiber having a shape memory capacity of 0. 0 ° C or more and a single fiber strength of 2.5 g / denier or more and a heat-fusible binder fiber, A second invention of the present application is based on a copolyester fiber laminate in which the copolyester of the first invention is polyethylene terephthalate obtained by copolymerizing a long-chain aliphatic dicarboxylic acid having 6 or more carbon atoms.

The present invention will be described in detail below.

The copolyester having shape memory ability used in the present invention has the following characteristics. (a) The shape is memorized when it is crystallized in a heating atmosphere after melt molding. (b) When an external force is applied in a temperature range higher than the glass transition point and lower than the temperature at which the shape is memorized, it deforms relatively easily. (c) If the temperature is below the glass transition temperature while maintaining the deformed shape, the deformed shape is fixed. (Shape-fixing ability) (d) Furthermore, if a temperature higher than the glass transition point is applied to this without applying an external force, the shape remembered in (a) is restored. (Shape recovery ability)

The glass transition point of copolyester is 4
When the temperature is about 5 ° C. or higher, the nonwoven fabric or the cotton wool prepared from the fiber laminate of the present invention has a firm texture similar to that of the ordinary polyethylene terephthalate, and reaches the glass transition point or higher up to room temperature or near body temperature. When heated, it returns to the memorized state. When the glass transition point is lower than room temperature or body temperature, the temperature is higher than the glass transition point during normal use, so that the body is soft and has a property of always returning to a memorized state. If the fiber laminate is heat-pressed at a high temperature to make a thin non-woven fabric, its flat state is memorized, and it becomes soft and more difficult to wrinkle.

The melting point of the copolyester must be 150 ° C. or higher. When the melting point is less than 150 ° C., the copolyester fiber having a shape memory capacity is softly deformed when the heat-fusible binder fiber is heated and fused, which is not practical.

Further, the single fiber strength of the copolyester fiber must be 2.5 g / denier or more. If the single fiber strength is less than 2.5 g / denier, productivity and quality will deteriorate due to single fiber breakage during the short fiber cotton making process or the process for preparing a fiber laminate, which is not practical.

Next, as a method of obtaining a copolyester having a shape memory ability, a method of copolymerizing an aromatic polyester segment (hard segment) and an aliphatic polyester segment (soft segment) at an appropriate ratio to obtain a polymer Another example is a method of copolymerizing an aromatic polyester segment (hard segment) and a polyalkylene glycol segment (soft segment) at an appropriate ratio to obtain a polymer, but the former is preferable.

The aromatic polyester segment means a polyester segment having at least one aromatic ring in the polyester repeating unit, and the aliphatic polyester segment means a polyester segment in which the polyester repeating unit is composed only of an aliphatic compound. Say that.

Examples of the aromatic monomer component constituting the hard segment include terephthalic acid, isophthalic acid, bisphenol A, dicarboxylic acids such as p-oxybenzoic acid, diols and hydroxycarboxylic acids.

Examples of the aliphatic monomer component which constitutes the hard segment with the aromatic monomer or the soft segment itself includes adipic acid,
Azelaic acid, dodecanedioic acid, eicosanedioic acid, ethylene glycol, butanediol, hexanediol, ε
-Dicarboxylic acids such as caprolactone, diols and oxycarboxylic acids (or lactones). Polyalkylene glycols such as polyethylene glycol and polytetramethylene glycol can also function as the soft segment component.

As the hard segment, polyester of ethylene terephthalate unit or butylene terephthalate unit is preferable, but ethylene terephthalate unit is most preferable in view of economy and physical properties.

The soft segment is preferably a long-chain aliphatic dicarboxylic acid such as azelaic acid, sebacic acid or dodecanedioic acid, and particularly an ester unit of an aliphatic dicarboxylic acid having 6 or more carbon atoms and ethylene glycol.

In the copolyester used in the present invention, it is considered that the soft segment acts as an intramolecular plasticizer to promote the crystallization of the polymer and causes the entanglement of the crystallized portions to give a fixed point. .. Even a copolyester consisting of only these hard and soft segments can be made into a polyester having sufficient shape memory capacity, but even if a molecular structure capable of intermolecular cross-linking is introduced, the rubber remembers its shape by vulcanization. Similar to the principle described above, it can function as a fixing point for fixing the shape to be memorized by cross-linking the polyester molecules at important points. Specific examples of the molecular structure capable of intermolecular crosslinking include a structure in which a monomer component having an unsaturated bond is copolymerized and an unsaturated bond is introduced into the main chain of polyester. Intermolecular cross-linking becomes possible by cleaving this unsaturated bond by an appropriate means when the shape is fixedly memorized.

Examples of monomer components which can be copolymerized with polyester and have an unsaturated bond include, for example, maleic anhydride, maleic acid, chloromaleic acid, itaconic acid, fumaric acid, citraconic acid, hettic acid, hettic anhydride, 2-
Examples thereof include unsaturated dicarboxylic acids or unsaturated diols such as butene-1,4-diol and 3-butene-1,2-diol.

It is also an effective means to copolymerize polyester with a trifunctional or higher functional monomer component to form a crosslinking point. Further, when the shape is fixed and stored, intermolecular crosslinking may be performed by adding and reacting a crosslinking agent having an isocyanate group, an amino group or the like that reacts with the hydroxyl group or the carboxyl group of polyester.

If desired, the polyester of the present invention may be copolymerized with other auxiliary raw materials as long as the object of the present invention is not impaired, and various additives are included. Good.

The constituent components of the monomers constituting the polyester used in the present invention and the copolymerization ratio thereof can be selected within a wide range, but in consideration of economical efficiency, versatility, physical properties, etc., for example, the following are preferable. .. That is, terephthalic acid as a dicarboxylic acid is 50 to 95 mol%, preferably 60 to 90 mol%, dodecanedioic acid is 5 to 50 mol%, preferably 10 to 40 mol%, and ethylene glycol is 100 mol% as a diol. It is a polyester used in proportion. In this example, the repeating unit consisting of ethylene glycol and terephthalic acid is the hard segment,
Repeating units consisting of ethylene glycol and dodecanedioic acid share the function of soft segment. Further, the glass transition point can be appropriately set in the range of 0 to 55 ° C. depending on the copolymerization amount of dodecanedioic acid.

The polyester fiber used in the present invention may be produced by a melt spinning method and a drawing method, like the general-purpose polyester fiber. Spinning conditions and drawing conditions differ depending on the physical properties of the shape-memory polyester used, but can generally follow conventional techniques. That is, spinning may be performed using a general-purpose spinning device or a composite spinning device. The spun fibers are
If necessary, it may be stretched or heat treated continuously or in a separate process.
It is subjected to high-level processing such as crimping and chemical treatment. Further, during spinning, additives such as a stabilizer, a fluorescent agent, a pigment and a reinforcing agent may coexist.

The fiber shape of the copolyester fiber may be a round cross section, an irregular shape such as a triangular cross section, or a hollow fiber. Further, it may be compounded with another polymer, or two types of polyester having different shape-polymerizing ability and having different degree of polymerization may be compounded side by side.

The fiber laminate of the present invention further contains a heat-fusible binder fiber. When the heat-fusible binder fiber is mixed and heated or heat-molded, the shape can be fixed to a non-woven fabric, cotton or a molded product having a desired shape, which is extremely useful industrially.

The heat-fusible binder fiber may be of any type as long as it is made of a polymer having a melting point of 10 ° C. or more lower than that of the main shape-memory copolyester, such as polyethylene, polypropylene, and other olefin-based or polyamide-based fibers. ， Polyester binder fiber is preferable,
Poly (ethylene terephthalate) or poly (butylene terephthalate) with isophthalic acid, diethylene glycol, 1,
A copolyester-based binder fiber obtained by copolymerizing 6-hexanediol or the like is more preferable. This heat-fusible binder fiber has not only fibers consisting of low melting point polymer but also core-sheath structure such as polyethylene terephthalate in the core or the polyester itself having shape memory ability, and low melting point polymer in the sheath. It can be used as a composite fiber. The heat-fusible binder fiber is usually 1
About 0 to 40% by weight is mixed.

The fiber laminate can be produced by opening and laminating a polyester having a shape memory ability and a heat-fusible binder fiber by a usual card method, air ray method, wet papermaking method or the like. Further, the bonding method may be appropriately selected depending on the purpose. The nonwoven fabric or the solid cotton is subjected to needle punching treatment or hydroentanglement treatment of the obtained fiber laminate, if necessary, and then heated at a temperature higher than the melting point of the heat-fusible binder fiber, a hot drum dryer, a saxion drum dryer, By using a heat treatment device such as a dryer such as a Yankee dryer or a heat roll such as a flat calendar roll or an embossing roll, a molded product having a curved surface or the like can be heat treated using a heat treatment device that can be heat-molded into a predetermined shape. Can be manufactured. In this heat treatment step, the crystallization or cross-linking reaction of the copolyester having shape memory ability is promoted, so that the shape during the heat treatment is memorized. Even if the memorized shape is destroyed during use or by washing, the memorized shape is restored by light heating above the glass transition point.

The fiber laminate of the present invention is a polyester fiber such as ordinary polyethylene terephthalate or polybutylene terephthalate having no shape memory ability, nylon fiber, rayon fiber, wool, cotton, etc. within the range of not impairing the shape memory ability. It may be a mixture of synthetic fibers such as hemp, recycled fibers and natural fibers.

[0030]

When the shape of the fiber laminate of the present invention is memorized in the process of heat treatment so that a fixed point is generated, it will return to its original shape when the temperature exceeds the glass transition point. The action works and it becomes possible to return to the original shape.

[0031]

EXAMPLES Next, the present invention will be described with reference to examples. In the examples, the characteristic values of polyester are measured as follows. (1) Intrinsic viscosity An equal weight mixture of phenol and ethane tetrachloride was used as a solvent, and measurement was performed at a temperature of 20 ° C. (2) Melting point and glass transition point Differential scanning calorimeter (Perkin Elmer, DSC-2)
Type) was used and the temperature was raised at a rate of 20 ° C./min.

Example 1 Bis (β-hydroxyethyl terephthalate) obtained by the esterification reaction of terephthalic acid with ethylene glycol and 45.0 kg of its oligomer were mixed with dodecanedioic acid.
5.8kg, maleic acid 0.4kg, ethylene glycol 9.0k
g, add 26 g of tetrabutyl titanate as a catalyst,
The esterification reaction was carried out at 250 ° C. under a nitrogen gas pressure of 3.6 kg / cm ² for 2 hours. The copolymerization amount of dodecanedioic acid was 10 mol% and the copolymerization amount of maleic acid was 1.5 mol%.

The obtained esterified product was transferred to a polycondensation reactor and subjected to a polycondensation reaction at 280 ° C. and 0.4 torr for 3 hours to obtain a copolyester A. The obtained copolyester A has a glass transition point of 49 ° C, a melting point of 232 ° C and an intrinsic viscosity of 0.
It was 65.

After the chips of copolyester A were dried under reduced pressure, they were melted using an ordinary melt spinning device, and the number of spinning holes was 2
Passing through 65 spinnerets, spinning temperature 270 ℃, total discharge 5
Melt spun at 20 g / min. After cooling the spun fiber yarn, it was taken out at a take-up speed of 1000 m / min to obtain an undrawn fiber yarn. The obtained yarns are bundled, made into a tow of 100,000 denier, and drawn at a draw ratio of 3.1, a drawing temperature of 60 ° C, and a temperature of 150 ° C.
After heat-treating with a heat drum, the crimp was applied using a push-in crimper. Then, it was cut into a length of 51 mm to obtain a copolyester fiber having a single yarn fineness of 6 denier, a single fiber strength of 4.2 g / denier, and an elongation of 83%.

This fiber and Melty <4080> (heat-fusion binder fiber manufactured by Unitika Ltd., single fiber fineness 4 denier, cut length 51 mm) were mixed at a ratio of 80:20 and then passed through a card machine to give a basis weight of 50 g / A web of m ² was used, and heat treatment was performed for 1 minute using a rotary dryer at a temperature of 140 ° C. to prepare a nonwoven fabric. Fold this non-woven fabric in half, 170 ℃
I remembered the crease by ironing. Subsequently, the nonwoven fabric was expanded and the fold was ironed at 70 ° C., and the fold disappeared. When this was left to stand in a dryer at 70 ° C. and taken out 2 minutes later, a clear crease was observed and shape memory ability could be confirmed.

Example 2 In the same manner as in Example 1, two kinds of fibers were mixed and passed through a card to prepare a web of 1300 g / m ² and heat-treated in a heat dryer at 160 ° C. for 10 minutes to give a thickness of 8 cm. I got cotton wool. A load is applied to the obtained cotton wool and compressed to a thickness of 2.5 cm, and in that state, it is treated with a heat dryer at a temperature of 70 ° C for 30 minutes and then taken out,
After cooling for 30 minutes at room temperature, the load was removed. After a further 30 minutes, the thickness N was measured and found to be 2.9 cm, which was fixed by compression. Compressed and fixed cotton wool at a temperature of 7 without load
It was confirmed that the sample was treated with a heat dryer at 0 ° C. for 30 minutes, taken out, and cooled at room temperature for 30 minutes, and then the thickness M was measured to be 7.8 cm, and the initial shape was recovered.

Examples 3 to 4 and Comparative Example 1 Copolyesters B to D were obtained in the same manner as in Example 1 except that maleic acid was not added and the copolymerization amount of dodecanedioic acid was changed. It was Table 1 shows the physical properties of these copolyesters. Furthermore, in the same manner as in Example 2 except that these copolyesters B to D were used in place of the copolyester A in Example 1 and the heat drum temperature in the drawing step and the heat oven treatment temperature at the time of making solid cotton were changed. Thus, the cotton wool of Examples 2-3 and Comparative Example 1 were obtained.
The shape memory ability is the same as that of the second embodiment.
Was measured and evaluated. The results are also shown in Table 1.

[0038]

[Table 1]

In Examples 3 and 4, similarly to Example 2, when the glass transition point or more was applied under compression, the material was compressed and fixed, and when treated without load, the original thickness was restored, and the shape memory ability was confirmed. However, in the case of Comparative Example 1 which is a copolyester fiber having a large copolymerization amount of dodecanedioic acid, both the compression fixability and the shape recovery property were poor.

Comparative Example 2 A copolyester E having an intrinsic viscosity of 0.44 was obtained by changing the polycondensation time in Example 1 to 1.5 hours. The glass transition point of this copolyester E is 47 ° C, and the melting point is 230 ° C.
Met. Except for using this copolyester E,
The same procedure as in Example 1 was carried out to obtain a copolyester fiber having a single fiber strength of 1.5 g / denier and an elongation of 80%. An attempt was made to make a non-woven fabric using this fiber in the same manner as in Example 1, but the single fiber breakage in the card machine was so severe that a satisfactory web could not be prepared, and the subsequent tests were cancelled.

[0041]

According to the present invention, a polyester fiber laminate having a shape memory ability can be obtained. Once the non-woven fabric prepared using this is modeled, even if the model is lost, it will return to its original modeled state by light heating. Moreover, the cotton swabs prepared using these have excellent shape-fixing properties and shape-recovering properties. Specific applications and effects include use as a non-woven fabric interlining and quilting batting, which recovers the shape by light heating even if it loses its shape, and retains its shape-retaining and heat-retaining effects for a long time. Used for wood,
Even when used, it is possible to utilize the effect of returning to the original bulky state with light heating.

Further, among the fiber laminates of the present invention, a polyester having a shape memory capacity and having a glass transition point exceeding room temperature is heat-bonded to form cotton wool, which is heated at a temperature not lower than the glass transition point. If the bulk of the cotton wool is reduced by pressing at a temperature below the temperature required for bonding the fusible binder fibers, and then cooled to a temperature below the glass transition point in that state, the shape is fixed in a low bulk state. To be done. If this is heated in a tension-free state immediately before use, it will return to the bulk at the time of heat-bonding, so it can also be used to reduce the transportation and storage costs of cotton wool. By setting the glass transition point near body temperature, it is possible to obtain soft and bulky sanitary materials such as disposable diapers and nappies when worn.

Claims (2)

[Claims] 1. A fiber laminate comprising a copolyester fiber having a shape memory capacity of 150 g or more and a single fiber strength of 2.5 g / denier or more and a heat-fusible binder fiber. 2. The copolyester fiber laminate according to claim 1, wherein the copolyester is polyethylene terephthalate obtained by copolymerizing a long-chain aliphatic dicarboxylic acid having 6 or more carbon atoms.