JPH06104932B2 - Thermal adhesive composite fiber - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat-adhesive conjugate fiber, and more particularly to a heat-adhesion conjugate fiber whose heat-adhesive component comprises a low-melting point copolyester and a modified polyolefin-based polymer.

(Prior Art) Conventionally, heat-adhesive fibers using a polyolefin-based polymer as a heat-adhesive component have been used for various non-woven fabrics, for example, non-woven fabrics for filters, food packaging, sanitary materials and the like.

In recent years, since the bulkiness of these non-woven fabrics has been required, polyester fibers have been used as the main fibers constituting the non-woven fabrics.

However, since the above-mentioned polyolefin component has a low adhesive strength to polyester fiber, it is not possible to obtain a high-strength nonwoven fabric, and it is not always satisfactory in terms of bulkiness.

Therefore, as an attempt to obtain a heat-adhesive composite fiber having a polyester fiber as a main fiber and excellent adhesive strength and bulkiness, a low-melting point copolyester having similar chemical structure and solubility parameter to polyester is used. A fiber having a polyester component having a melting point of 200 ° C. or more as a non-heat-adhesive component (main component) as a heat-adhesive component (hereinafter referred to as a composite fiber) has been proposed (for example, JP-A-57-101018).
Issue).

Further, it has been proposed to blend "ionomer" with a low melting point copolyester as a heat-adhesive component in order to prevent the fibers from sticking together in the production of such a composite fiber (JP-A-57-128216). .

The "ionomer" referred to in JP-A-57-128216 is an α-olefin modified with a metal salt of an unsaturated carboxylic acid.

However, the polyester non-woven fabric obtained by using the composite fiber blended with the ionomer has a drawback that it does not exhibit sufficient strength and high bulkiness almost like the non-woven fabric obtained by mixing and spinning conventional polyolefin fibers and polyester fibers. It was

Recently, in non-woven fabrics for food packaging and the like, a non-woven fabric is laminated with a polyolefin film, and then cut to be a desired product. In such processing, good adhesiveness and cuttability between the non-woven fabric and the polyolefin film are required, and further, the obtained non-woven fabric is required to have high strength and flexibility.

The inventors of the present invention have found that the above-mentioned composite binder fiber is insufficient for these requirements.

(Object of the Invention) An object of the present invention is to provide a polyester fiber, and a composite fiber which has improved adhesiveness to a polyolefin-based film and is easily cuttable, and which can give a flexible nonwoven fabric having high strength. Especially.

(Structure) In order to achieve the above-mentioned object, the present inventors are not useful to include a polyolefin polymer having low rigidity and low affinity as a heat-adhesive component, which has affinity for the low-melting point copolyester. I thought about it.

As a result, a modified polyolefin copolymer and a low melting point copolymer polyester modified with a lower alkyl ester of acrylic acid and / or methacrylic acid and an aliphatic unsaturated dicarboxylic acid or an anhydride thereof and containing substantially no metal component. When a blend consisting of and is used as a heat-adhesive component, a high-strength and flexible polyester non-woven fabric can be obtained, and the resulting non-woven fabric has good adhesiveness and cuttability with a polyolefin film. Found and arrived at the present invention.

Thus, according to the present invention, (1) the following modified olefin-based polymer and a low-melting-point copolyester having a melting point of 170 ° C. or less are provided on the periphery of at least a part of the high-melting point polyester component having a melting point of 200 ° C. or more. Thermoadhesive composite fiber characterized by having a blended body modified olefin-based polymer: a copolymer composed of the following monomers a, b and c and containing substantially no metal component: a. Acrylic acid and / Or lower alkyl ester of methacrylic acid b. Aliphatic unsaturated dicarboxylic acid or anhydride thereof c. Olefin (2) Olefin-based homopolymer on at least part of the periphery of the high melting point polyester component having a melting point of 200 ° C or higher, A ternary blend consisting of the following modified olefin polymer and low melting point copolyester having a melting point of 170 ° C or less is joined. Thermoadhesive conjugate fiber.

Modified olefin polymer: a copolymer composed of the following monomers a, b and c and containing substantially no metal component a. Lower alkyl ester of acrylic acid and / or methacrylic acid b. Aliphatic unsaturated dicarboxylic acid Or its anhydride c. An olefin.

The "melting point" in the present invention refers to the softening point in the case of amorphous polyester.

In the present invention, the heat-adhesive component of the conjugate fiber needs to be a blend of the modified polyolefin polymer and the low melting point copolyester as described above.

The modified polyolefin-based polymer is modified with the a-component and the b-component that do not substantially contain a metal component.

Here, in the case of using a blend consisting of an unmodified polyolefin-based polymer which is not modified with an unsaturated carboxylic acid compound of a and b and a low-melting point copolyester as a heat-adhesive component, an olefin and a low-melting point polyester are used. Due to poor compatibility, spinnability is extremely poor and stable production is difficult. Further, even if a product is obtained, the nonwoven fabric shows good adhesiveness with respect to adhesion with a polyolefin film, but the thermal adhesive strength with the polyester fiber, which is the main fiber constituting the nonwoven fabric, decreases, A high-strength non-woven fabric cannot be obtained. Moreover, the texture of the non-woven fabric itself becomes hard.

Further, in the case of the above-mentioned composite fiber, the high melting point polyester component (non-heat-adhesive component) constituting the binder fiber and the heat-adhesive component are easily cut off and the cuttability of the nonwoven fabric is deteriorated.

On the other hand, even if it is a modified polyolefin-based polymer, if it is a so-called "ionomer" modified with a metal salt of an unsaturated carboxylic acid, the resulting nonwoven fabric and the polyolefin-based film have insufficient adhesion, Also has poor flexibility, strength, and cuttability. In addition, the composite fiber containing the ionomer as the heat-adhesive component has a drawback that it tends to yellow in the manufacturing process of the nonwoven fabric.

The reason for this is that the ionomer has poor compatibility with polyester due to its high polarity and also has high rigidity, and further, because the ionomer has hygroscopicity, it deteriorates polyester during heat treatment in the manufacturing process of nonwoven fabric. It is speculated that this is due to the ionomer itself turning yellow.

In this respect, the modified polyolefin-based polymer used in the present invention has a low polarity because it does not substantially contain a metal component like an ionomer, has good compatibility with polyester, and has low rigidity and hygroscopicity. .

In the present invention, both a and b components are first used that do not contain a metal component. Here, the lower alkyl in the component a refers to an alkyl group having 1 to 4 carbon atoms. The component a may be not only a single component but also a prepolymerized olefin.

On the other hand, examples of the component b include unsaturated carboxylic acids such as maleic acid or esters thereof, or unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride. Among these, maleic anhydride is particularly preferred as the b component to be combined with the a component, which improves the compatibility with the low melting point polyester, the thermal stability, the softening of the texture, the adhesiveness, and the cutting property. The improvement is preferably achieved.

Further, as the c component, ethylene, propylene and other α
-Olefins or mixtures thereof. The ratio of the a, b, and c components forming the modified polyolefin-based polymer is expressed in mol%: a: b: c = (0.3 to 30): (0.3 to 2
0): (99.4 to 50), more preferably a: b: c = (0.
5 to 20): (0.5 to 10): (99 to 70). a, b
If both components are less than 0.3 mol%, the effect aimed at by the present invention cannot be obtained, and if the amount of the component a exceeds 30 mol%, and the amount of the component b exceeds 20 mol%, the melting point decreases and the modified polymer becomes difficult to handle. Poor, and tends to be difficult to melt-spin.

Examples of the modified polyolefin-based polymer include copolymers having a molecular weight of 10,000 or more.

The modified polyolefin polymer is preferably a random copolymer with the components a and b, having a melt index of 0.1 to 200, particularly 1 to 40, and finally having a molecular weight of 10,000 to 5 It may be adjusted so that it will be a million olefins. Further, as the modified polyolefin, one having a melting point of 65 to 170 ° C., preferably 75 to 130 ° C. is used from the viewpoint of adhesiveness.

The amount of such a modified polyolefin polymer blended in the heat-adhesive component is preferably 0.5 to 90% by weight, more preferably 25 to 50% by weight, based on the heat-adhesive component.

In the case of a composite fiber composed of a heat-adhesive component with a modified polyolefin polymer content of more than 90%, the adhesive strength with the polyester fiber, which is the main fiber constituting the non-woven fabric, tends to decrease, and the cutting property is also inferior. Become. On the other hand, if the blending amount is less than 0.5% by weight, the adhesiveness between the obtained nonwoven fabric and the polyolefin film tends to decrease.

On the other hand, as the low melting point polyester which constitutes the heat-adhesive component together with the modified polyolefin-based polymer, one having a melting point of 170 ° C. or lower (softening point in the case of amorphous polyester) is used. With a composite binder fiber containing a polyester having a melting point of more than 170 ° C. as a heat-adhesive component, it is not possible to obtain a high-strength nonwoven fabric at the heat treatment temperature (130 to 180 ° C.) usually adopted in the production of nonwoven fabric.

As such a low melting point polyester, 50 mol% or more of the total acid component is a terephthalic acid component, and 40 mol% or less is an isophthalic acid component, and 80 mol% of the diol component is a hexamethylene glycol component, a tetramethylene glycol component, or Copolymerized polyesters having an ethylene glycol component are preferred.

In particular, a crystalline copolyester containing 50 mol% or more of the total acid component as a terephthalic acid component, 40 mol% or less as an isophthalic acid component, and 80 mol% of the diol component as a hexamethylene glycol component or a tetramethylene glycol component. It is preferable that the melting point is 110 to 150 ° C.

The blending amount of such low melting point polyester in the heat-adhesive component is preferably 10 to 99.5% by weight, particularly preferably 50 to 75% by weight.

The heat-adhesive component in the present invention basically comprises the above-mentioned modified polyolefin polymer and low melting point polyester, but it may also contain an unmodified polyolefin polymer. The non-modified polyolefin-based polymer is preferably polyethylene, polypropylene, or a copolymer thereof.

When such an unmodified polyolefin-based polymer is contained, it is expected that various functions of the heat-adhesive component will be deteriorated, but as long as the modified polyolefin-based polymer used in the present invention coexists, it is surprising. The compatibility between the non-modified polyolefin-based polymer and the low melting point polyester is maintained very well.

In this case, the composition of the heat-adhesive component is such that the low melting point polyester component is 10 to 90% and the modified polyolefin polymer is 3 to
It is preferable that 80% and 87 to 7% of the non-modified polyolefin-based polymer (all of them are weight%).

The conjugate fiber of the present invention has a melting point of 200 with the above-mentioned thermoadhesive component.
Consists of a polyester component having a high melting point of ℃ or higher.

The high melting point polyester component having a temperature of 200 ° C. or higher prevents shrinkage of the binder fiber during heat treatment during the production of the nonwoven fabric, and retains the compression recovery property and dimensional stability of the resulting nonwoven fabric.

As the high melting point polyester, polyethylene terephthalate or polybutylene terephthalate is preferable, and a small amount of 10 mol% or less, especially 3 mol% or less of the third component may be copolymerized with respect to the acid component and / or the glycol component. Alternatively, it may be a blend with another polymer.

The third component is isophthalic acid, naphthalene-2,6-dicarboxylic acid, adipic acid, sebacic acid, 5
-Aromatic or aliphatic dicarboxylic acid components such as sodium sulfoisophthalic acid, diethylene glycol, neopentyl glycol, cyclohexane-1,4-dimethanol,
Examples thereof include diol components such as 1,6-hexanediol, polyalkylene glycol, glycerin, pentaerythreath, and bisphenol A.

Examples of the blended polymer include the above-mentioned modified polyolefin, non-modified polyolefin, low melting point polyester, polyamide and the like.
A blending amount of less than or equal to wt% is preferable in terms of further improvement in adhesiveness, cutting property, and softening.

The high melting point polyester preferably has an intrinsic viscosity [η] of 0.3 to 0.5 in order to improve the cuttability of the resulting nonwoven fabric.

In the composite fiber of the present invention, the composite state of the high melting point polyester component and the heat-adhesive component may be any of the conventionally known composite states such as side-by-side type and core / sheath type. Although good, it is necessary that at least a part, preferably 40% or more, of the fiber surface is occupied by the heat-adhesive component. The most preferred is the core / sheath type composite state, in which the ratio of the core portion (high melting point polyester component) and the sheath component (heat adhesive component) in the fiber cross section is 3
It is preferably 0:70 to 90:10.

Further, the single fiber denier of the composite binder fiber of the present invention is
0.1 to 20 de is preferable, and hollow fibers (hollow ratio 50% or less) may be used.

Such a composite fiber of the present invention can be applied to a wet non-woven fabric and a dry non-woven fabric, and when it is used for the wet non-woven fabric, it is preferable that the following properties (1) to (5) are simultaneously satisfied.

Number of crimps: 0 to 15 pcs / 25 mm (particularly preferably 0 to 10 pcs / 25 mm) Fiber length: 35 mm or less (particularly preferably 2 to 20 mm) On the other hand, in the case of a composite fiber used for a dry nonwoven fabric, the following (i ) To (iv) are preferable at the same time.

(I) Number of crimps: 5 to 25 pieces / 25 mm (particularly preferably 8 to 20 pieces / 25 mm) (ii) Crimp elasticity: 70% or more (particularly preferably 75% or more) (iii) Fiber length: 35 ~ 200 mm (iv) (Melting point of heat-adhesive component −15 ° C.) heat shrinkage ratio: 10% or less The crimp elasticity here is obtained by the method of JIS L 1015. .

The composite fiber of the present invention described above is obtained by melt spinning a mixture containing a low melting point polyester and a modified polyolefin-based polymer or an unmodified polyolefin, and a high melting point polyester using a conventionally known composite spinneret. Obtainable.

In this case, the low melting point polyester and the modified polyolefin-based polymer may be blended in advance before melt spinning, or may be blended during melt spinning.

The melting temperature of the heat-adhesive polymer component during melt spinning is
In order to prevent gelation and improve the spinning tone, the temperature is preferably 150 to 250 ° C, more preferably 180 to 230 ° C. On the other hand, the melting temperature of the high melting point polyester component is preferably 260 to 300 ° C. for improving the spinning tone.

In order to improve the spinning tone, it is preferable that the polymers are separately transported in the conduit at different temperatures and are compounded in the pack immediately before spinning. The spinning temperature is preferably a temperature suitable for spinning a high melting point polyester, and it may normally be in the range of 260 to 290 ° C. It is preferable that the discharged yarn is cooled immediately below the spinneret to prevent sticking and improve the spinning condition.
The take-up speed is preferably in the range of 350 to 3000 m / min from the viewpoint of spinning tone.

The undrawn yarn thus obtained is made into a tow of 400 to 3 million denier, then drawn at a draw ratio of 2.0 to 4.5 times at a temperature of 60 to 95 ° C., and then crimped with an indenting crimper to make it necessary. And then cut into staple fibers.

Silk factor of the composite fiber of the present invention Is preferably in the range of 5 to 18, and particularly preferably in the range of 7 to 15 from the viewpoint of improving the cutting property.

In the present invention, a matting agent such as titanium oxide, an antistatic agent, a conductive agent, a dye improving agent, a heat stabilizer and the like are blended or copolymerized in the heat adhesive component and / or the high melting point polyester component. May be.

(Function) One of the major features of the modified polyolefin-based polymer of the present invention is that the olefin (c component) which has unsaturated bonds and has no unsaturated bond in all of a, b, and c components and which does not have a carboxy group.
On the other hand, a monomer having one carboxyl group (a component), a monomer having two carboxyl groups (b component), and a monomer in which the carboxyl group is increased stepwise in the range of 0 to 2 are combined. With such a combination, and since the metal component is not substantially contained in the polymer, the compatibility with polyester and olefin is remarkably improved.
As a result, the conjugate fiber of the present invention is mainly composed of a non-woven fabric because its heat-adhesive component is a blend of a modified polyolefin-based polymer component and a low-melting-point polyester component that are compatible with the polyester component and have low rigidity. The resulting non-woven fabric is flexible and has improved adhesiveness with a polyolefin film.

In addition, the heat-adhesive component and the high-melting-point polyester component that compose the conjugate fiber are not easily peeled off during cutting, so that the cutability of the resulting nonwoven fabric is also improved.

(Examples) Next, the present invention will be described in detail by examples.

In the examples, the numbers indicating the copolymer composition amounts represent mol% based on the total acid component and the total glycol component, respectively. In addition, all parts indicate% by weight.

(1) Measurement of non-woven fabric strength Heat-bondable composite fiber and polyethylene terephthalate (PE
T) staple fiber (6de, 51mm) is mixed at a weight ratio of 50:50, carded, and then heat-treated for 2 minutes at 150 ° C with a hot air circulation type heat treatment machine to obtain an adhesive web with a basis weight of about 30g / m ² . (Nonwoven fabric) was prepared and the adhesive strength was measured.
The non-woven fabric strength was a value obtained by dividing the tensile breaking force in the machine direction of a non-woven fabric sample having a width of 15 mm by the weight.

(2) Recovery bulk Apply a load of 100 g / cm ^{2 to} the adhesive web (thickness L ₀ mm) 24
Hold for time. Then, the load was removed, and after 24 hours, the thickness (L ₁ mm) of the adhesive web was measured, the recovery rate of the adhesive web was calculated from the following formula, and the recovery bulk was evaluated.

Recovery bulk (%) = (L ₁ / L ₀ ) × 100 (3) Bulkiness The obtained nonwoven fabric is cut into 10 cm length × 10 cm width and the height when 5 sheets are laminated is measured. The specific volume was measured and calculated.

(4) Adhesiveness with polyolefin film (heat sealability) Cut the above adhesive web into 5 cm width and 10 cm length in the machine direction,
Take two sheets, and put a polyethylene-based sheet (0.03 mm thick) made by Fukusuke Kogyo Co., Ltd., 5 cm in length and width between the non-woven fabric, and sandwich it between the non-woven fabric edges. cm
It was fused with 2 seconds press at ² of the load. Then, both ends on the non-heat-bonded side of the non-woven fabric were sandwiched by a chuck and the peel strength was measured.

Heat seal strength is 1c from the beginning of peeling off the heat seal part
m The average value of peeling was used.

(5) Cleavability of non-woven fabric The above adhesive web is cut into 5 cm width and 10 cm length in the machine direction,
Five sheets were laminated and cut with a guillotine cutter.

The cutability was determined by observing the cut portion and making the following determinations.

◎: The non-woven fabric is completely cut ○: The non-woven fabric is connected by several single fibers △: The non-woven fabric is almost uncut ×: The non-woven fabric is not cut at all (6) Texture The obtained non-woven fabric was judged by touch.

The abbreviations used for the copolyester in this example have the following meanings.

TA: terephthalic acid component IA: isophthalic acid component EG; ethylene glycol component TMG; tetramethylene glycol component HMG; hexamethylene glycol component Example 1 As a core component, polyethylene terephthalate (intrinsic viscosity
0.45, melting point 260 ℃) melted at 290 ℃, as a sheath component TA90mol%, IA10mol%, HMG90mol%, EG10mol% low melting polyester (melting point 115 ° C) and maleic anhydride 1mol% And a mixture of modified polyethylene with a melt index of 5 and a melting point of 95 ° C (mixing ratio 65/35) obtained by random copolymerization of 4 mol% of ethyl acrylate with 200 ° C Using the core-sheath type composite spinneret, a composite ratio of 50/50 (% by weight) was spun at a spinning temperature of 280 ° C., and the film was wound at a spinning speed of 1000 m / min.

Next, the undrawn yarn thus obtained was made into a tow of 2 million denier and then drawn 3.0 times with hot water at 70 ° C. to obtain a drawn yarn having a single fiber fineness of 3 denier. The drawn yarn was crimped by a stuffing box type crimping machine, subjected to a relaxation heat treatment at 100 ° C., and then cut into a fiber length of 51 mm to obtain a heat-bondable composite fiber. Such a fiber has a single fiber fineness of 3 de, a silk factor of 13, a crimp number of 15/25 mm, a crimp degree of 16%, a crimp elasticity of 77%,
The dry heat shrinkage was 80% at 1% or less.

The strength, the recovered bulk, the bulkiness, the adhesiveness with the polyolefin film, the cuttability, and the feel of the nonwoven fabric obtained by using this composite binder fiber were evaluated, and the results are shown in Table 1.

Comparative Example 1 Example 1 was repeated except that the modified polyolefin polymer was not mixed.

The silk factor of the obtained composite binder fiber is 21, and the evaluation results of the non-woven fabric obtained by using the same are shown in Table 1.

Comparative Example 2 The procedure of Example 1 was repeated except that polyethylene having a melt index of 5 and a melting point of 125 ° C. was used in place of the modified polyolefin-based polymer at a low melting point polyester: polyethylene mixing ratio = 95/5. (Low-melting point polyester: polyethylene: Mixing ratio = 65/35 was not possible for spinning, so the mixing ratio of polyethylene was reduced.) The resulting composite binder fiber had a silk factor of 20.
Table 1 also shows the evaluation results of the non-woven fabric obtained by using this.

Example 2 Various materials shown in Table 2 were used in combination as the core component and the sheath component, and a composite fiber was obtained by the method according to Example 1 to form a composite fiber. The results are shown in Table 3.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Motomiya 77 Kitayoshida-cho, Matsuyama-shi, Ehime Teijin Stock Company Matsuyama Factory (72) Inventor Mikio Tashiro Kitayoshida-cho, Matsuyama-shi, Ehime Teijin Stock Company Matsuyama Factory (72) Inventor Makoto Yoshida 3-4-1 Mihara, Ibaraki-shi, Osaka Inside Textile Processing Laboratory, Teijin Limited (56) Reference JP-A-63-41549 (JP, A)

Claims (2)

[Claims] 1. A blended product of the following modified olefin polymer and a low melting point copolyester having a melting point of 170 ° C. or less is joined to the outer periphery of at least a part of a high melting point polyester component having a melting point of 200 ° C. or more. A thermo-adhesive composite fiber characterized by being present. Modified olefin-based polymer: Copolymer consisting of the following monomers a, b and c and containing substantially no metal component a. Lower alkyl ester of acrylic acid and / or methacrylic acid b. Aliphatic unsaturated dicarboxylic acid Or its anhydride c. Olefin 2. An olefin homopolymer, a modified olefin polymer described below, and a melting point of 170 on the periphery of at least a part of a high melting point polyester component having a melting point of 200 ° C. or higher.
A thermoadhesive conjugate fiber, characterized in that a ternary blend comprising a low melting point copolyester at a temperature of ℃ or below is joined. Modified olefin polymer: a copolymer composed of the following monomers a, b and c and containing substantially no metal component a. Lower alkyl ester of acrylic acid and / or methacrylic acid b. Aliphatic unsaturated dicarboxylic acid Or its anhydride c. Olefin