JP2790572B2 - Thermal adhesive fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed heat-bondable fiber having excellent card passing properties. More specifically, the present invention relates to a heat-adhesive fiber which has a good passing property in a cotton-making process and a high-speed card, and from which a high-quality nonwoven fabric can be obtained without inhibiting adhesion.

[0002]

2. Description of the Related Art Conventionally, various types of heat-adhesive fibers have been proposed for non-woven fabrics, and mainly sheath / core type composite fibers such as low-melting polyester / polyethylene terephthalate (hereinafter referred to as PET), polyethylene / polypropylene, and the like. Polyethylene / PET is used. In recent years, the demand for these heat-adhesive fibers has been increasing, especially for foods such as cosmetic puffs, wet tissues, and tea bags.
For applications such as household nonwoven fabrics, sanitary napkins, surface materials such as disposable diapers, and diaper liners and sanitary and medical nonwoven fabrics such as compress base fabrics, there are only demands for performance such as high adhesive strength and soft texture. In addition, it is required that the productivity of the nonwoven fabric be excellent.

However, in order to increase the productivity of the nonwoven fabric, the card speed is increased from the usual value of about 50 m / min to 100 to 12 m / min.
If the speed is increased to 0 m / min, the following troubles occur. In other words, in order to obtain a nonwoven fabric exhibiting a soft feeling, a polymer modified polymer, particularly an olefin-based copolymer is usually used as the heat-adhesive component, but since this polymer has a large flexibility, When the speed of the card is increased, the heat-adhesive fibers are easily deformed by the external force of the card clothing, etc., and the friction with the metal is increased, so that the card becomes easy to drip, and the winding of the cylinder and the winding of the combing roller may occur. It will be easier. For this reason, the obtained web also has drawbacks such as nep generation, and it is difficult to obtain a nonwoven fabric with stable quality. Furthermore, since the coefficient of friction between fibers is small due to the characteristics of the polyolefin-based polymer itself, there is also a problem in that if the card speed is increased, troubles such as slippage of the web and generation of fluff occur.

[0004] To solve such a problem, the present inventors
Previously, a method for attaching a treating agent containing a specific polyvinyl alcohol compound to the fiber surface was proposed. According to such a method, a uniform web could be obtained without any problem at a card speed of 100 to 120 m / min. However,
In recent years, there has been a demand for the development of a heat-adhesive fiber capable of supporting a higher speed, for example, about 130 m / min, and there has been a limit.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and an object of the present invention is to provide a nonwoven fabric which is excellent in high-speed card passing properties, has a soft feeling, and has high adhesive strength. To provide a heat-bondable fiber for a dry nonwoven fabric.

[0006]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, have been able to increase the friction between metal and fiber by providing a treating agent containing a specific polypeptide. The present inventors have found that the friction between fibers can be significantly increased without further consideration, and further studied based on such findings, and as a result, the present invention has been achieved.

That is, according to the present invention, the melting point is 50 to
In the case of a thermoadhesive fiber having a thermoadhesive component of a thermoplastic polymer having a temperature of 200 ° C. and 50% by weight or more of a polyolefin polymer, the fiber surface has a molecular weight of 100 to 500.
A heat-adhesive fiber characterized in that the polypeptide of No. 00 adheres to the fiber in an amount of 0.01 to 5% by weight based on the weight of the fiber and has a crimp of 10 to 18 peaks / 25 mm. Is done.

Examples of the polypeptide to be contained in the treating agent used in the present invention include those obtained by hydrolyzing a bio-related substance, for example, a protein obtained from bovine leather or the like, and having a molecular weight of 100 to 50,000. It is necessary to be. When the molecular weight is less than 100,
The effect of increasing the friction coefficient between fibers tends to decrease, and the high-speed card passing property tends to decrease.
If it exceeds 00, the solubility in water becomes small and emulsification is difficult, and the liquid stability of the treating agent is undesirably reduced.
In particular, it is desirable to be in the range of 500 to 7000. Further, the terminal of the polypeptide may be a long-chain acyl group such as n-
_{C 7 H 15 CO-, n-} C 11 H 23 CO-, n-C 13 H 27 C
Blocking with O—, n—C ₁₅ H ₃₁ CO— or the like is preferable because surface activity is improved, dispersibility in water is improved, and liquid stability of the treating agent is improved.

In the present invention, the processing agent containing the above-mentioned polypeptide may be added to other processing agent components, for example, a leveling agent, an anionic activator, a nonionic activator, and, if necessary, an antistatic agent and a brightening agent. , An antioxidant, an ultraviolet absorber, a pigment, a dye, and the like.

[0010] The heat-adhesive fiber of the present invention must have 0.01 to 5% by weight, preferably 0.2 to 0.6% by weight of the above polypeptide attached to the fiber weight.
If the adhesion amount is less than 0.01% by weight, sufficient fiber
It is not suitable for high-speed cards because of the lack of fiber-to-fiber friction. on the other hand,
If it exceeds 5% by weight, the friction between the metal and the fiber is increased, so that card neps are easily generated, troubles such as powdering are apt to occur, and the adhesive strength is undesirably reduced.

In the present invention, the number of crimps is 10 to 1
It is important to have a crimp of 8 ridges / 25 mm, preferably 12 to 16 ridges / 25 mm. If it is less than 10 ridges / 25 mm, entanglement between fibers even if the treatment agent is applied. In the case of a high-speed card, the trouble of cutting the web is apt to occur, while if it exceeds 18 mountains / 25 mm,
It is not preferable because the fiber opening property in the cotton blending step is reduced and a nep or the like is easily generated.

Further, the fiber of the present invention has a degree of crimp and a degree of crimp elasticity (JIS L) from the viewpoint of the entanglement property and the opening property of the fiber.
1015) are desirably 8% or more and 70% or more, respectively, and the fiber length is suitably 20 to 90 mm, particularly 30 to 60 mm. It is desirable that the fineness is 1.0 to 20 denier and the heat shrinkage at 80 ° C. is 10% or less.

In the present invention, the heat-adhesive fiber to which the treatment agent is adhered has a melting point (softening point of an amorphous polymer).
It is important that a thermoplastic polymer having a temperature of 50 to 200 ° C. is used as a heat-adhesive component, and at least 50% by weight of the thermoplastic polymer is a polyolefin-based polymer.

The heat-adhesive fiber may be a fiber consisting of an adhesive component alone or a composite fiber (core-sheath type, side-by-side type, etc.) with another fiber-forming polymer. Good. Also, the cross-sectional shape is round, flat, T
Any form, such as a multi-leaf irregular cross section such as a mold, a Y-type, a positive mold, and a variant, a hollow section, and a variant hollow section may be used. In particular, those having a hollow portion having a hollow ratio of 3 to 40% improve the bulk of the nonwoven fabric.

Next, polyolefin polymers preferably used as the adhesive component include, for example, polyethylene, polypropylene, polybutene-1, polypentene, and the like.
1 and their random or block copolymers, or, further, methacrylic acid, acrylic acid, fumaric acid,
Examples thereof include polyolefin-based polymers obtained by copolymerizing at least one kind selected from unsaturated carboxylic acids such as crotonic acid and itaconic acid, and derivatives thereof (referred to as modified olefins). Above all, from the viewpoint of the process stability during cotton production and the feeling (flexibility) of the nonwoven fabric, one or more unsaturated carboxylic acids and α of ethylene, propylene, butene-1, etc.
-A modified polyolefin obtained by copolymerizing at least one olefin is preferable.

The heat-adhesive component other than the polyolefin-based polymer is not particularly limited as long as its melting point is in the range of 50 to 200 ° C., as described above, and is not limited to polyvinyl acetate, polyacrylate, or a copolymer thereof. Examples thereof include coalesced polyamides such as Nylon 10 and Nylon 12, and copolyamides, polyesters, and copolyesters. Particularly, those having a melting point of 90 to 150 ° C are preferable.

On the other hand, other fiber-forming polymers constituting the composite fiber include thermoplastic polymers having a melting point of 150 ° C. or higher and a melting point higher than that of the heat-adhesive component, for example, PET, P
BT, Nylon-6, Nylon-66, polypropylene, etc., and especially PE in terms of bulkiness, settling resistance, elasticity, and soft feeling of the finally obtained nonwoven fabric.
T or PBT is preferred. The ratio of the fiber-forming polymer to the entire circumference of the cross section of the conjugate fiber, that is, the fiber cross-sectional circumference is preferably 60% or less (the ratio of the heat bonding component occupies 40% or more). When the affinity between the heat-sensitive polymer and the heat-adhesive component is insufficient and interface delamination is likely to occur, the heat-adhesive component or a polymer having a high affinity with the heat-adhesive component is used at a ratio of 40% by weight or less. It is preferable to mix it with a hydrophilic polymer from the viewpoint of improving the adhesive strength.

The heat-adhesive fiber of the present invention may be used alone to form a nonwoven fabric, or may be used by mixing with ordinary fibers such as polyester short fibers and polypropylene short fibers. It can be selected as appropriate.

[0019]

The heat-adhesive fiber of the present invention described above is provided with a treatment agent containing a specific fiber-to-fiber friction improver and at the same time, an appropriate crimp. Therefore, the card has excellent cardability at an ultra high speed of 120 to 130 m / min or more, and the production efficiency is remarkably improved. In addition, the use of a polyolefin-based polymer as the heat-adhesive component is the same as before, in that a nonwoven fabric of a stable quality with a soft feel and no decrease in adhesive strength can be obtained. Is extremely large.

[0020]

EXAMPLES The present invention will be described more specifically with reference to the following examples. In addition, evaluation of each physical property followed the following method.

(1) High-speed card passability Under a condition of 25 ° C. × 65% RH, 50 kg of raw cotton was applied to a roller card to prepare a web having a basis weight of 20 g / m ² . At this time, the web breaks even when spun at a spinning speed of 130 m / min.
Good for those that could be spun smoothly without troubles such as nep generation and cylinder wrapping: good, good for those with the above-mentioned troubles with a maximum spinning speed of 120 to 130 m / min: △, less than 120 m / min Was bad: x.

(2) Treatment Agent Stability A treatment liquid having an active ingredient content of 8% by weight was prepared, and the treatment liquid was used to form a yarn. In this case, the processing liquid has a high stability and the stretching condition is good, and the production can be stably performed: ○, the stretching condition is unstable in some places, but the operation production is possible: Δ, the processing solution stability is poor. Bad troubles often occur during production:
X.

(3) Feeling A web having a basis weight of 30 g / m ² obtained at a spinning speed of 130 m / min with a high-speed card machine under the conditions of 25 ° C. × 65% RH was used.
Heat treatment was performed at 40 ° C. for 20 seconds to obtain a nonwoven fabric (thickness: about 5 mm), and the obtained nonwoven fabric was judged by a tactile sensation by five panelists. ：: All are judged as good △: 3 to 4 are judged as good ×: 3 or more are judged as bad

(4) Adhesive strength A test piece having a width of 6 cm and a length of 20 cm was cut out from the nonwoven fabric prepared in the same manner as described above, and a gripping interval of 10 cm was cut.
cm and an elongation rate of 20 cm / min. The adhesive strength was a value obtained by dividing the tensile strength at break by the weight of the test piece.

(5) Overall judgment ：: good Δ: acceptable ×: unacceptable

[0026]

Examples 1-4, Comparative Examples 1-5 Polyethylene terephthalate having an intrinsic viscosity of 0.64 (melting point: 260
° C) and high-density polyethylene (melting point 1
30 ° C.) 80 parts and ethylene / methyl methacrylate /
Maleic anhydride copolymer (copolymer molar ratio 90/6/4,
(Melting index: 8, melting point: 95 ° C.) Using a heat-adhesive component consisting of 20 parts, a spinning temperature of 280 ° C. and a spinning speed of 1000 m were obtained from a core-sheath composite spinneret having 210 holes.
/ Min at a composite ratio of 50/50 (weight ratio). Next, the obtained undrawn yarn was collected to make a 2,000,000 denier tow, and then drawn 3.0 times in hot water at 80 ° C. to obtain various treatment agents (10% aqueous emulsion) shown in Table 1. It was provided with an adhesion rate (as an active ingredient) shown in FIG. The drawn yarn was supplied to an indentation crimping machine and crimped as shown in Table 1 was applied.
Relaxation heat treatment at 00 ° C, cut into 38mm fiber length,
A heat adhesive fiber having a short fiber fineness of 3.0 denier and a dry heat shrinkage of 80 ° C. of 1% or less was obtained.

Table 1 shows the results of evaluation using these heat-adhesive fibers in accordance with the above evaluation method. In addition, the adhesive strength is obtained when the heat-bondable fiber alone is used as a nonwoven fabric.

[0028]

[Table 1]

[0029]

Examples 5 to 7 and Comparative Example 6 A heat-adhesive fiber was obtained in the same manner as in Example 1 except that the heat-adhesive component shown in Table 2 was used as the sheath component. The obtained heat-bondable fiber was evaluated in the same manner as in Example 1. Table 3 shows the results.

[0030]

[Table 2]

[0031]

[Table 3]

Continuation of front page (56) References JP-A-62-250278 (JP, A) JP-A-61-163850 (JP, A) JP-A-62-156356 (JP, A) (58) Fields investigated (Int) .Cl. ⁶ , DB name) D06M 15/15 D01F 8/04

Claims (1)

(57) [Claims] 1. A heat-adhesive fiber having a melting point of 50 to 200 ° C. and a heat-adhesive component of a thermoplastic polymer whose polyolefin polymer is 50% by weight or more, wherein the fiber surface has a molecular weight of 100 to 100%. 50,000 polypeptides are attached at 0.01 to 5% by weight with respect to the fiber weight, and the number of crimps is 1
A heat-adhesive fiber having a crimp of 0 to 18 peaks / 25 mm.