JPH04240219A - Polyester-based heat bonding conjugate fiber - Google Patents

Abstract

PURPOSE:To obtain heat bonding conjugate fiber capable of simultaneously imparting excellent elasticity characteristics and shape retaining properties to a cushioning material composed of polyester fiber. CONSTITUTION:Conjugate fiber composed of a polyester component having >=200 deg.C melting point and a polyether ester block copolymer component having specific melt viscosity characteristics in which 50-80mol% of an acid component is terephthalic acid; the main glycol component is 1,4-butanediol and the amount of a copolymerized poly (alkylene oxide) glycol component is 30-50wt.%. Since thermally fused points between fibers are formed from the specific block copolymer, a cushioning material extremely improved in bonding strength and elastic recovery characteristics is obtained.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to polyester-based heat-adhesive conjugate fibers, and particularly to heat-adhesive conjugate fibers suitable for bonding polyethylene terephthalate (hereinafter sometimes referred to as PET)-based fibers. be. More specifically, the present invention relates to a thermoadhesive conjugate fiber that provides excellent elastic properties (compression properties, elongation properties) and shape retention when used in cushioning materials such as nonwoven fabrics and batting made of polyester fibers.

0002

BACKGROUND OF THE INVENTION Currently, in the field of cushioning materials for furniture, beds, etc., urethane foam, polyester fiber batting, resin cotton bonded with polyester fibers, solid cotton, and the like are used.

[0003] However, urethane foam has problems in that it is difficult to handle chemicals and the like used during manufacture, and it also emits fluorocarbons. In addition, the compression properties of the resulting urethane foam are hard at the initial stage of compression and then suddenly sink, resulting in poor cushioning properties, a strong feeling of bottoming out, and poor air permeability, making it easy to get stuffy. It is often not preferred as a material. Furthermore, since the polymer is soft and foamed, it has the disadvantage that it must have a high density in order to provide resilience against compression. In addition, because the fibers and structure of polyester fiber filling are not fixed, it has the disadvantage that its shape may collapse during use, the fibers may move, or the crimping may become flat, resulting in a significant decrease in bulk and resilience. .

On the other hand, resin cotton or hard cotton made by bonding polyester fibers with resin or low melting point polymer (for example, Japanese Patent Laid-Open No. 58
-31150, etc.), the adhesive is weak, the durability of the adhesive part is low, the adhesive breaks down during use and the form and repulsion properties are greatly reduced, and the adhesive is molded hard, so only products with poor cushioning properties can be obtained. There are disadvantages such as not being able to In order to improve cushioning properties, a cushioning material in which intertwined portions of polyester fibers are bonded with a foamed urethane binder has been proposed, as in JP-A-62-102712, but since it is impregnated with solution-type urethane, it is difficult to process. It has problems such as being prone to spots and being troublesome to handle, poor adhesion between urethane and fibers, low elongation of the binder and easy to break when intertwined parts are greatly deformed, and low durability. be.

[0005]

SUMMARY OF THE INVENTION In view of the problems of the prior art described above, the present invention aims to provide a cushioning material that exhibits excellent cushioning properties, has excellent durability and stability, and is highly breathable through a simple process. The purpose of the present invention is to provide a polyester-based heat-adhesive conjugate fiber suitable for manufacturing.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present inventors have conducted intensive studies and found that the present invention is composed of specific constituent components and has an intrinsic viscosity and melt viscosity within a specific range under specific conditions. It has been found that when a polyester thermoadhesive conjugate fiber containing a specific polyether ester block copolymer as a thermoadhesive component is applied to a cushioning material, a cushioning material excellent in the above properties can be obtained. As a result of further studies based on this knowledge, the present inventors have completed the present invention.

That is, according to the present invention, (1) in a composite fiber consisting of a polyester component having a melting point of 200°C or higher and a polyetherester block copolymer component having a melting point of 180°C or lower, the polyetherester block The copolymer contains (A) terephthalic acid in proportion to 5% of the total acid components.
The polyether ester comprises an acid component containing 0 to 80 mol%, (B) a glycol component mainly containing 1,4-butanediol, and (C) a poly(alkylene oxide) glycol component having an average molecular weight of 400 to 4000. The copolymerization amount of the component (C) in the block copolymer is 30 to 50% by weight, and the melt viscosity MV (Pois) at 180°C is
e) and intrinsic viscosity IV after being held in air at 180°C for 3 minutes
satisfies the following formulas (I) and (II) at the same time, and (I) 4000-2500×IV<MV<10
000-2500×IV (II) 0.6<IV
<1.5 [However, MV is a shear rate of 10 at 180°C
The melt viscosity at 00 sec-1 and IV indicate the intrinsic viscosity in an orthochlorophenol solution at 35°C. ] and a polyester-based heat-adhesive composite fiber characterized in that the polyether ester block copolymer component accounts for 40% or more in terms of fiber cross-sectional circumference; and (2) a terminal end of the polyether ester block copolymer. The carboxyl group concentration is 30 equivalents/106 g or more (
1) The polyester thermoadhesive composite fiber described above, and (
3) There is provided a polyester thermoadhesive conjugate fiber according to (1) or (2) above, wherein the conjugate fiber is a core-sheath type conjugate fiber.

The polyester used in one of the composite fibers of the present invention is not particularly limited as long as it has a melting point of 200° C. or higher and has fiber-forming properties, but polyesters such as polyethylene terephthalate, polybutylene terephthalate, Alternatively, a copolymerized polyester obtained by copolymerizing these with a small amount of a third component is preferable.

[0009] Preferably used copolymerization components include:
For example, dicarboxylic acid components such as isophthalic acid, adipic acid, sebacic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, propylene glycol, diethylene glycol, neopentyl glycol, polyethylene glycol, p-xylylene glycol , 1,4-cyclohexanedimethanol, diol components such as 5-sodium sulforesorcin, polyfunctional carboxylic acid components such as trimellitic acid and pyromellitic acid, p
Examples include difunctional monocarboxylic acids such as -oxybenzoic acid and p-oxyethoxybenzoic acid.

[0010] Furthermore, the polyether ester block copolymer, which is another component constituting the composite fiber of the present invention, has a copolymerization ratio of the copolymer to the total acid components (expressed in mol% relative to the total acid components). Terephthalic acid as 50 ~
The one containing 80 mol% is used. Acid components other than terephthalic acid include isophthalic acid, phthalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, 2,6-
Naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, 1,4-cyclohexanedicarboxylic acid, etc. are preferably used.

The polyether ester block copolymer used in the present invention has 1,4-butanediol as its main glycol component. Note that the "main" here
This means that 80 mol% or more of all glycol components is 1,4-butanediol, and other types of glycol components may be copolymerized within a range of 20 mol% or less. Preferably used copolymerized glycol components include:
Ethylene glycol, trimethylene glycol, 1,5
-pentanediol, 1,6-hexanediol, diethylene glycol, 1,4-cyclohexanediol,
Examples include 1,4-cyclohexanedimethanol.

Furthermore, the polyether ester block copolymer used in the present invention has an average molecular weight of 400 to 40
00 poly(alkylene oxide) glycol component to 3
It contains 0 to 50% by weight. If the average molecular weight is less than 400, the blocking properties of the resulting block copolymer will be reduced and the elastic recovery performance will be insufficient;
If it exceeds 0, the copolymerizability of the poly(alkylene oxide) glycol component decreases, resulting in severe phase separation of the resulting polymer, resulting in insufficient elastic recovery performance, which is not preferred. In addition, if the copolymerization amount is less than 30% by weight,
Even if the composite fiber is heated and bonded and molded into a cushioning material, etc., it will not be possible to obtain the good elastic properties that are the object of the present invention. This is undesirable because it reduces physical properties and durability such as heat resistance and light resistance.

Preferably used poly(alkylene oxide) glycols include polyethylene glycol,
Examples include poly(propylene oxide) glycol, poly(tetramethylene oxide) glycol, and a homopolymer of poly(tetramethylene oxide) glycol is particularly preferred. Furthermore, a random copolymer or a block copolymer in which two or more types of repeating monomers constituting the homopolymer are randomly or block-copolymerized may be used; You may use the mixed polymer which mixed two or more types of these.

The polyether ester block copolymer used in the composite fiber of the present invention must satisfy the above compositional conditions, and according to further studies by the present inventors,
In order to ensure process stability during composite fiber production and quality such as elastic properties and thermal adhesion, it is also important to keep the melting point, melt viscosity, and intrinsic viscosity of the copolymer within appropriate ranges. I discovered that.

That is, the polyether ester block copolymer according to the present invention has a melting point of 180° C. or lower. If the melting point exceeds 180°C, the heat treatment temperature when manufacturing nonwoven fabrics, cushioning materials, etc. from the composite fiber of the present invention must be set to 180°C or higher, and thermal decomposition of the block copolymer may occur during this heat treatment. As a result, the mechanical properties of the resulting nonwoven fabric, cushioning material, etc. will deteriorate.

Further, the block copolymer used in the present invention has a melt viscosity MV at 180°C (shear rate 1000
sec-1) and the intrinsic viscosity IV after being held in air at 180° C. for 3 minutes must satisfy the following formulas (I) and (II).

(I) 4000-2500×IV<MV<10
000-2500×IV (II) 0.6<IV
<1.5 If IV is less than 0.6, the mechanical performance of the final nonwoven fabric or cushioning material will be inferior, while if it is more than 1.5, the fluidity of the block copolymer will decrease, resulting in poor adhesion during heat treatment. Not only is this insufficient, but the heat treatment temperature also needs to be set high, resulting in thermal decomposition of the block copolymer and deterioration of its elastic properties.

[0018] Also, 180°C, shear rate 1000 sec
Melt viscosity MV at -1 is 4000-2500×IV
In the following cases, when producing composite fibers, the spinning condition deteriorates, such as breakage during spinning, and even if the fiber aggregate mixed with other fibers is heat-treated, flow occurs at the bonded part. The adhesive strength is reduced and the elastic and mechanical properties are insufficient. On the other hand, if it exceeds 10000-2500×IV,
Since the fluidity during heat treatment is too low, sufficient adhesion between the fibers does not occur, resulting in insufficient elastic properties and mechanical properties, which is not preferable.

In the present invention, the terminal carboxyl group concentration (CV) of the block copolymer is further adjusted to 30 equivalents/10
It is preferable that the amount is 6 g or more, thereby improving the adhesive strength between fibers and further improving the elastic properties of nonwoven fabrics, cushioning materials, etc.

The polyether ester block copolymer described in detail above can be produced in accordance with conventionally well-known methods for producing ordinary copolyester polyesters. Specifically, a terephthalic acid component, a dicarboxylic acid component other than terephthalic acid, a glycol component mainly consisting of 1,4-butanediol, and poly(alkylene oxide) glycol are placed in a reactor, and the mixture is heated in the presence of a catalyst or in the absence of a catalyst. In this method, a transesterification reaction or an esterification reaction is carried out in the presence of a catalyst, and then a polycondensation reaction is carried out in a high vacuum in the presence of a catalyst to increase the degree of polymerization to a desired degree.

In the present invention, the melting point Tm of the block copolymer, melt viscosity MV at 180°C, 180°C3
In order to set the intrinsic viscosity IV and the terminal carboxyl group concentration after the minute retention within the above range, the above polymerization reaction conditions were appropriately set, and the physical properties of the block copolymer were taken into account, taking into account the rate of change in physical properties of the block copolymer due to the spinning method. It is necessary to

For example, the intrinsic viscosity depends on the polymerization time, polymerization temperature, stirring speed, type of catalyst, amount of catalyst added, etc. As the amount increases, the intrinsic viscosity can be increased, and the intrinsic viscosity after being held in air at 180° C. for 3 minutes also increases.

Melt viscosity MV is determined by the intrinsic viscosity of the block copolymer, the type of components constituting the block copolymer, the poly(
It depends on the molecular weight and copolymerization amount of glycol (alkylene oxide), the type and amount of other additives such as stabilizers and antioxidants, or the melting point Tm of the block copolymer. In general, the MV can be increased by reducing the amount of copolymerized poly(alkylene oxide) glycol, increasing the amount of additives, or increasing the melting point.

The melting point of the block copolymer depends on the composition and copolymerization ratio of the polyester segments constituting the block copolymer, as well as the average molecular weight of the poly(alkylene oxide) glycol. , reduce dicarboxylic acid components other than terephthalic acid, or reduce poly(alkylene oxide) components.
The higher the average molecular weight of the glycol, the higher the melting point.

Furthermore, the terminal carboxyl group concentration CV depends on the polymerization time, polymerization temperature, type and amount of catalyst added, intrinsic viscosity of the block copolymer, etc. Generally, the longer the polymerization time and the higher the polymerization temperature, the larger the CV can be.

[0026] Therefore, the above polymerization conditions and composition, etc.
All you have to do is change and combine them as appropriate.

The above-mentioned polyether ester block copolymer according to the present invention contains matting agents, pigments (for example, carbon black, etc.), antioxidants (for example, hindered phenol compounds, hindered amine compounds), as well as ordinary polyesters. There is no problem in including a UV absorber (for example, a benzophenone compound, a benzotriazole compound, a sacylate compound, etc.), a crosslinking agent (isocyanate compound, etc.), etc.

The polyester heat-adhesive conjugate fiber of the present invention is obtained by composite spinning the above-described polyester component having a melting point of 200°C or higher and a polyetherester block copolymer component having a melting point of 180°C or lower. in this case,
Although the composite ratio is not particularly limited, it is preferable that the proportion of the block copolymer component to the total circumference of the composite fiber cross section, that is, the fiber cross-sectional circumference, is 40% or more, such as side-by-side bimetal type, core-sheath type. Alternatively, an eccentric core-sheath type conjugate fiber can be exemplified. Among these, eccentric core-sheath type composite fibers are preferred because they can be easily crimped by heat treatment or the like, and therefore can be easily passed through the carding process.

Furthermore, the heat-adhesive composite fiber of the present invention has 1
．． Preferably, the fibers are drawn five times or more. A cushioning material made of stretched fibers has superior elasticity and is less likely to sag than a cushioning material made of unstretched fibers. The reason for this is not clear, but when the drawn fibers are heat-treated in a relaxed state, the amorphous part of the block copolymer component is relaxed, resulting in a polymer structure with better elastic properties. It is presumed that this is because it is maintained even after being molded into a cushioning material or the like.

[0030] Furthermore, the conjugate fiber of the present invention desirably has a low shrinkage rate, and is preferably heat-set. That is, if the shrinkage rate is high, it will shrink significantly during thermal bonding processing, which will reduce the efficiency of thermal bonding between fibers, resulting in not only a decrease in the resilience of the resulting cushion material but also an extremely hard texture.

The conjugate fiber of the present invention may be used alone as a fiber aggregate for nonwoven fabrics, cushioning materials, etc., but it may also be used as a mixed aggregate with other fibers containing 20% by weight or more of the conjugate fiber. In particular, when fibers made of polyester such as polyethylene terephthalate and polybutylene terephthalate are used as the mixed fibers, the thermal adhesion not only between the composite fibers of the present invention but also between the mixed fibers and the composite fibers is good. Therefore, it is possible to obtain fiber aggregates such as cushioning materials that have excellent mechanical properties and elastic properties.

[0032] In order to heat-treat the fiber aggregate containing the composite fibers of the present invention to fuse and integrate them, the temperature must be 20 to 80°C higher than the melting point of the block copolymer, and the temperature must be 20 to 80°C higher than the melting point of the block copolymer. The treatment may be performed at a temperature lower than the melting point of the polyester component and other fibers mixed in the fiber aggregate. If this processing temperature is too low, the molten polymer will not be able to properly flow and bond to the intertwined parts, and the number of intertwined parts of the fibers to be integrated by heat fusion will decrease, reducing the repulsion of the fiber aggregate of the cushioning material. descend. Furthermore, if the processing temperature is too high, the block copolymer will be altered by heat, resulting in a product with poor elasticity and significant discoloration.

[0033]

Effects of the Invention In the fiber aggregate made of the polyester heat-adhesive conjugate fiber of the present invention, the fibers are thermally fused by heating, and this fusion point is a polyether ester block copolymer having specific performance. Since it is formed from coalescence, the fiber aggregate has extremely excellent properties such as strength and elasticity (deformation recovery). In particular, when mixed with regular polyester short fibers to make a cushioning material, compared to the conventionally widely used urethane foam, there is no initial hardness when compressed, and the resilience is large and increases almost in proportion to the amount of compression. Therefore, it is possible to obtain a product with excellent properties such as extremely little feeling of bottoming out, and low density and good breathability, so there is no need to worry about stuffiness. In addition, since the adhesion between fibers is good, the bonded part is difficult to break when deformed, and although it is easy to deform, it has good recovery properties, and its durability against repeated compression is the same as that of urethane. It's normal.

[0034] Furthermore, when producing these fiber aggregates, uniform fiber aggregates can be easily obtained through a simple and short process of forming a web and then subjecting it to heat treatment. Furthermore, by changing the blending ratio of the fibers, the composition, or the density of the fiber aggregate, the hardness can be arbitrarily changed in both the thickness direction and the plane direction.

[0035] Therefore, the cushioning material made using the composite fiber of the present invention has excellent cushioning properties, durability, and stability, has high breathability, is resistant to stuffiness, is resistant to uneven processing, and can be processed in a variety of ways. It is a cushioning material that is easy to use, and its range of uses is suitable for various cushioning materials, such as furniture, beds, bedding, seat cushions, etc.

[0036]

[Examples] The present invention will be specifically explained below with reference to Examples. In the examples, all "parts" indicate parts by weight. Note that evaluations in Examples were measured by the following method. 1. Intrinsic viscosity (IV) Measured at 35°C in orthochlorophenol solvent. 2. Melting point (Tm) The melting peak temperature was determined using a thermal differential analyzer model 990 manufactured by Du Pont at a heating rate of 20° C./min. 3. Melt viscosity (MV) Temperature 180°C, shear rate 10-10000 sec-1
The apparent melt viscosity (MV) was measured in the range of 1,000 sec-1, and the melt viscosity (MV) at a shear rate of 1000 sec-1 was calculated. 4. Terminal carboxyl group concentration (CV) 0.1 g of polymer is dissolved in 10 ml of benzyl alcohol, 10 ml of chloroform is added, and then titrated with sodium hydroxide-benzyl alcohol. Use phenol red as an indicator. 5. Measurement of compression elasticity and compression durability of cushioning material Molded into a flat plate, density 0.035g/cm3, thickness 5cm
m cushioning material is compressed by 1 cm using a cylindrical rod with a cross-sectional area of 20 cm2 and a flat bottom surface, and its stress (initial stress) is
) was measured. 10 with a load of 800g/cm2 after measurement
After compressing for seconds, unloading and leaving it for 5 seconds, it becomes 36
Compression and standing were repeated 0 times, and the compressive stress was measured again 24 hours later. The ratio of the stress after repeated compression to this initial stress (%) was defined as the compression durability of the cushioning material.

[0037]

[Examples 1 to 6, Comparative Examples 1 to 8] 117.1 parts of dimethyl terephthalate, the polytetramethylene glycol listed in Table 1, additives, catalysts, and 1,4-butanediol (1.4 parts of the acid component) (mole times) into the reactor, and the internal temperature was 19
The transesterification reaction was carried out at 0°C. Approximately 80% of the theoretical amount
After methanol was distilled off, the polycondensation reaction was started by raising the temperature and reducing the pressure. The polycondensation reaction is carried out while gradually reducing the pressure.
After reaching a vacuum of 1 mmHg or less, the reaction was carried out at the internal temperature and time described in Table 1.

The polyether ester block copolymer produced was pelletized.

This polyether ester block copolymer was used as a sheath and polyethylene terephthalate was used as a core, and the fibers were spun in a conventional manner so that the core/sheath weight ratio was 50/50. Note that this composite fiber is an eccentric core-sheath type composite fiber. After stretching this fiber 2.0 times and cutting it into 64 mm, 95
It was heat-treated with warm water at ℃ to reduce shrinkage and develop crimp, and after drying, an oil agent was applied. Note that the single fiber fineness of the composite short fibers obtained here is 6 denier.

[0040] 40% of composite short fibers containing this polyether ester block copolymer and 60% of hollow cross-section polyethylene terephthalate short fibers having a single filament fineness of 6 denier and a fiber length of 64 mm obtained by a conventional method were mixed using a card. A web (web volume 120 cm3/g) was obtained. Layer this web to a thickness of 5cm and a density of 0.035g/cm.
3 and heat-treated at 200° C. for 10 minutes to obtain a flat cushion material. The properties of the obtained cushioning material are shown in (Table 2).

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

[Table 4]

Claims (3)

[Claims] Claim 1: A composite fiber comprising a polyester component having a melting point of 200°C or higher and a polyetherester block copolymer component having a melting point of 180°C or lower, wherein the polyetherester block copolymer comprises (A) terephthalic acid. An acid component containing 50 to 80 mol% of the total acid component, (
B) a glycol component mainly consisting of 1,4-butanediol, (C) a poly(alkylene oxide) glycol component having an average molecular weight of 400 to 4000, and the (C) component in the polyether ester block copolymer. The amount of copolymerization is 30 to 50% by weight, and the melt viscosity MV (Poise) at 180°C and the intrinsic viscosity IV after being held in air at 180°C for 3 minutes simultaneously satisfy the following formulas (I) and (II). , (I)4000-2500×IV<MV<10
000-2500×IV (II) 0.6<IV
<1.5 [However, MV is a shear rate of 10 at 180°C
The melt viscosity at 00 sec-1 and IV indicate the intrinsic viscosity in an orthochlorophenol solution at 35°C. ] A polyester thermoadhesive composite fiber characterized in that the polyether ester block copolymer component accounts for 40% or more in fiber cross-sectional circumference. 2. The polyester thermoadhesive conjugate fiber according to claim 1, wherein the polyether ester block copolymer has a terminal carboxyl group concentration of 30 equivalents/10 6 g or more. 3. The polyester thermoadhesive conjugate fiber according to claim 1 or 2, wherein the conjugate fiber is a core-sheath type conjugate fiber.