JPH05132817A - Binder fiber - Google Patents

Abstract

PURPOSE:To obtain a binder fiber having excellent adhesiveness to polyester fibers and giving a sufficient adhesion strength by the heat-treatment at a relatively low temperature for a short time by using a specific copolymerized polyester containing a bisphenol derivative as a hot-melt component. CONSTITUTION:The objective binder fiber contains a hot-melt component consisting of a copolymerized polyester having an intrinsic viscosity [eta] of >=0.6 and containing (A) >=95mol% (based on the copolymerized ratio based on the total acid component) of terephthalic acid, (B) >=60mol% of 1,6-hexanediol and (C) 5-40mol% of a bisphenol derivative of formula [X is C(CH3)2, SO2 or S].

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to binder fibers. More specifically, it has excellent adhesiveness to polyester fibers, and a sufficient adhesive strength can be obtained by heat treatment at a relatively low temperature for a short time, and a step in producing the fibers (a step of producing a copolyester and a fiber of the polyester). Process)
The present invention relates to a binder fiber that can be stably produced without trouble.

[0002]

2. Description of the Related Art In the use of non-woven fabrics, as the proportion of polyester fibers has increased, there has been a demand for binder fibers containing a polyester polymer having good adhesiveness to polyester fibers as an adhesive component. Further, in the production of non-woven fabrics and the like, from the viewpoint of production efficiency and energy saving, a method of bonding by a heat treatment at a relatively low temperature of 100 to 150 ° C. for an extremely short time (10 seconds or less) is often used. As such, a low melting point crystalline polyester having a low melting point and good crystallinity is required. In addition, process characteristics when producing heat-bondable fibers (for example, a cutter process in which a molten polymer is taken out of a polymerization tank to form a pellet, a drying process before spinning, a fusion process of chips or single fibers in a spinning drawing process, etc. Polyester having good crystallinity is also melted from the viewpoint of adhesion. In order to meet these requirements, a method using a copolyester obtained by copolymerizing polyhexamethylene terephthalate with isophthalic acid has been proposed (Japanese Patent Publication No. 3-47325).
Publication). However, even in this method, since the glass transition temperature of the copolyester is as extremely low as about −10 ° C., it is often difficult to pelletize the polymer in the conventional polyester production equipment, and the spinning and drawing are performed. The fiber sticking in the process was still unsatisfactory.

[0003]

As described above, the present invention is excellent in adhesiveness to polyester fibers such as polyethylene terephthalate, and particularly at low temperature (100
We do not provide binder fiber that can achieve stable adhesion with sufficient heat treatment for a short time and has good processability such as the production of copolymer polyester which is a heat-adhesive component and the production of fiber. It is what

[0004]

Means for Solving the Problems As a result of intensive studies on the above fibers, the present inventors have found that a polyhexamethylene terephthalate polyester copolymerized with a specific modified bisphenol as a copolymerization component is used as a heat-adhesive component. The present invention has been completed by discovering that the resulting fiber has excellent process stability and adhesiveness during production.

That is, according to the present invention, the terephthalic acid content is 95 mol% or more as a copolymerization ratio with respect to all acid components.
1,6-hexanediol is 60 mol% or more, the bisphenol derivative represented by the following formula (I) is 5 to 40 mol%, and the intrinsic viscosity [η] thereof is 0.6 or more. Binder fiber as an ingredient,

[0006]

[Chemical 2] Will be provided.

The copolyester used as the heat-adhesive component in the binder fiber of the present invention contains terephthalic acid in an amount of 95 mol% or more, particularly preferably 100 mol%, based on the total acid component. The acid component may contain, for example, isophthalic acid at 5 mol% or less.

The copolyester according to the present invention contains 60 mol% or more of 1,6-hexanediol,
Moreover, it is important that the bisphenol derivative represented by the following general formula (I) is contained in an amount of 5 to 40 mol%, preferably 20 to 30 mol%.

[0009]

[Chemical 3]

In the formula, X represents a divalent linking group selected from --C (CH ₃ ) _2- , --S-- and --SO _2- , among which --C (CH ₃ ) ₂ --is economically advantageous. preferable. 1,6-
When the copolymerization ratio of hexanediol is less than 60 mol%, the crystallinity of the copolymerized polyester is lowered, and the polymer chips are easily fused or the binder fiber obtained is apt to stick, resulting in process troubles. It is not preferable because it occurs frequently.

In the present invention, since the specific amount of the bisphenol derivative is contained as described above, it is possible to obtain the one having a low melting point required for the binder fiber while maintaining the glass transition temperature of the copolyester. The property and the process stability in producing the binder fiber can be solved at the same time. This copolymerization amount is 5 mol%
If it is less than 40 mol%, sufficient adhesive strength cannot be obtained by heat treatment at low temperature, while if it exceeds 40 mol%, the crystallinity of the copolyester will be excessively lowered and the process stability will be lowered. Not preferable.

In the present invention, in addition to the above-mentioned glycol component, another glycol component may be copolymerized within a range not impairing the object of the present invention.

The copolymerized polyester can be produced by a conventionally known method. For example, the dicarboxylic acid component and the glycol component are subjected to an esterification reaction or a transesterification reaction in the presence or absence of a catalyst to obtain a bisglycol ester and / or an initial condensate thereof. Then, a polycondensation reaction is carried out in the presence of a polycondensation catalyst to easily obtain. At this time, when a titanium compound, particularly a reaction product of a tetraalkyl titanate and an organic carboxylic acid and / or an acid anhydride thereof, is used as a polycondensation catalyst, the polycondensation reaction rate is increased, and a polyester having a high degree of polymerization is easily obtained. It is preferable because it can be obtained. The tetraalkyl titanate used for producing such a reactive product has an alkyl group having 3 to 4 carbon atoms, particularly tetrapropyl titanate,
Tetraisopropyl titanate and tetrabutyl titanate are preferable, and as the organic carboxylic acid and / or its acid anhydride, aliphatic carboxylic acids such as acetic acid and propionic acid, phthalic acid, trimellitic acid, hemimellitic acid, and pyromellitic acid. Examples of the aromatic polycarboxylic acid, and their acid anhydrides. The conditions for reacting these are not particularly limited, and can be easily obtained by, for example, dissolving each component in a solvent such as ethylene glycol and reacting at about 80 ° C. for about 60 minutes.

The amount of the polycondensation catalyst used is not particularly limited, but if it is too small, the polycondensation reaction rate is slow, while if it is too large, the hue of the resulting polyester tends to deteriorate (yellowing).

Therefore, in the case of the above reaction product, the titanium atom in the reaction product is 0.005 to 0.1 mol% with respect to the acid component of the copolyester, though it depends on the kind of the catalyst used. In particular, an amount of 0.01 to 0.05 mol% is preferable.

The intrinsic viscosity [η] of the copolymerized polyester thus obtained (measured at 30 ° C. in an orthochlorophenol solvent) must be 0.6 or more, preferably 0.7 or more, particularly preferably 0.8 or more. is there. Intrinsic viscosity is 0.6
If it is less than the above range, the mechanical properties of the copolyester are deteriorated, and the strength of the finally obtained heat-bonded product such as a nonwoven fabric is insufficient, which is not preferable.

The copolymerized polyester used in the present invention may contain a small amount of additives such as matting agents, antioxidants, optical brighteners, stabilizers and ultraviolet absorbers.

The binder fiber of the present invention may be a fiber obtained by spinning the above copolymerized polyester alone, but a composite fiber spun with another melt-spinnable polymer is more preferable.

As such a polymer, a thermoplastic polymer having a fiber-forming property and a melting point of 180 ° C. or higher is used. For example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), nylon-6, nylon-6,6, etc. Is preferably used. Further, the copolyester serving as an adhesive component needs to occupy at least a part of the surface of the composite fiber, preferably 40% or more. If the copolymerized polyester is not exposed on the surface of the composite fiber, a sufficient adhesive effect cannot be obtained, which is not preferable. The area ratio of the copolyester is preferably 1 in any cross section of the composite fiber.
0-70%, more preferably 30-70%, especially 30-
It is desirable to set it to 50%.

The composite fiber may take any form such as a side-by-side type composite fiber, a core-sheath type composite fiber, etc.
A core-sheath type composite fiber containing a fiber-forming polyester such as BT as a core component is particularly preferable.

The binder fiber of the present invention can be used as an adhesive fiber aggregate composed of only this, but may be used as a mixed adhesive fiber aggregate with other fibers containing 10% by weight or more of the fiber.

[0022]

INDUSTRIAL APPLICABILITY The binder fiber of the present invention has excellent adhesiveness to polyester fibers such as polyethylene terephthalate, and at the same time has extremely good productivity, which is of great industrial significance.

[0023]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition, the part in an Example shows a weight part. Various characteristics were evaluated by the following methods.

(1) Intrinsic viscosity [η] Measured at 30 ° C. using orthochlorophenol as a solvent,
The relative viscosity was determined by a conventional method.

(2) Adhesive strength The binder fiber (6 denier x 6 cm) thus obtained and the staple fiber (6 denier x 6 cm) made of polyethylene terephthalate with a crimping rate of 10% were weighed in the card at a weight ratio of 20:80. The sliver was blended in proportion and the pull-out strength was measured. On the other hand, the sliver prepared in the same manner was heat-treated at 160 ° C. for 30 seconds under a load of 5 g / cm ² to measure the pull-out strength, and the adhesive strength was determined by the following formula. Adhesive strength = (pull-out strength after heat treatment) / (pull-out strength before heat treatment)

[0026]

Example 1 970 parts of dimethyl terephthalate, 1,6-
442 parts of hexanediol and 474 parts of a bisphenol A derivative represented by the following formula (abbreviated as BPA-2)

[0027]

[Chemical 4]

Furthermore, 0.34 parts of tetrabutyl titanate as an ester exchange catalyst and polycondensation catalyst was charged into a reactor equipped with a stirrer, a rectification column and a methanol distillation condenser, and the temperature was gradually raised from 140 ° C. The transesterification reaction was carried out while distilling the produced methanol out of the system. 3 hours after the reaction started, the internal temperature reached 220 ° C,
318 parts were distilled. The reaction product was transferred to a reactor equipped with a stirrer and a glycol distillation condenser. Then, the reaction product was cooled to 200 ° C. and then cooled to 200 ° C.
Temperature gradually rises from 1 to 240 ° C and normal pressure to 1mmHg
The polycondensation reaction was performed while reducing the pressure to the high vacuum. The melt viscosity of the reaction system was traced, and the polycondensation reaction was terminated when [η] reached 0.800.

The molten polymer was extruded in the form of a strand from the bottom of the reactor into cooling water and cut into pellets by using a strand cutter. No pellet fusion occurred and the cutter process was very good.

Using the obtained copolymerized polyester as a sheath and polyethylene terephthalate having an intrinsic viscosity [η] = 0.64 as a core, spinning was performed at a sheath / core = 50/50 weight ratio. It was discharged at a die temperature of 220 ° C. and taken at a take-up speed of 800 m / min. There was no sticking between fibers and the spinning process was good. Further, this yarn was stretched 3.5 times at 78 ° C. in a water bath, then contracted at 87 ° C. by 10% in a water bath, and crimped at a crimping rate of 10% by an indentation type crimper. 60 mm and 51 mm of the obtained crimped yarn
Then, it was cut to obtain a binder fiber having a single yarn denier of 6 denier. The adhesive strength of this product was 36. The above results are summarized in Table 1.

[0031]

Examples 2 and 3, Comparative Examples 1 to 3 Copolymerized polyester and binder fiber were obtained in the same manner as in Example 1 except that the composition of the copolymerized polyester was changed as shown in Table 1.
The results are also shown in Table 1.

[0032]

[Table 1]

Claims (1)

[Claims] 1. As a copolymerization ratio to all acid components, terephthalic acid is 95 mol% or more, 1,6-hexanediol is 60 mol% or more, and a bisphenol derivative represented by the following formula (I) is 5 to 40 mol%. And a binder fiber containing a copolyester having an intrinsic viscosity [η] of 0.6 or more as a heat-adhesive component. [Chemical 1]