JPH10317264A - Melt blown nonwoven fabric made of high-performance elastomer with improved adhesiveness and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer having excellent stretchability, which is sticky and adhered to a production facility such as a net conveyor at the time of melt blown spinning, and it is difficult to exfoliate well. Is still left as an issue.
To solve this, and to obtain a melt blown nonwoven fabric having more excellent stretch characteristics. [Structure] The fibers constituting the melt blown nonwoven fabric are composed of a core and an adhesive component (A) made of a thermoplastic elastomer.
A high-performance, melt-blown nonwoven fabric made of a high-performance elastomer having improved adhesiveness, which is a core-sheath type composite fiber also made of a thermoplastic elastomer but having a non-adhesive component (B) as a sheath.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretchable nonwoven fabric obtained by spinning a thermoplastic elastomer by a melt blow method, and more particularly to a stretchable nonwoven fabric obtained by meltblown spinning of a sticky (adhesive) thermoplastic elastomer. The present invention relates to a melt blown nonwoven fabric for maximally effectively utilizing the stretch characteristics without killing the stretch blown nonwoven fabric. Further, the present invention relates to a method for producing such a nonwoven fabric stably on an industrial scale. In this specification, both the sticking and the adhesion are collectively referred to simply as sticking.

[0002]

2. Description of the Related Art It is known that a thermoplastic elastomer is spun by a melt blow method to form a nonwoven fabric. For example, "Espansione" obtained by a melt blow method using a thermoplastic polyurethane [manufactured by Kanebo Co., Ltd.] [Product Name] is on the market.

By the way, in the production of a nonwoven fabric by a melt blow method, a molten polymer is discharged from a spinning nozzle.
By blowing out heated air from gas outlets arranged on both sides of the nozzle discharge port, the discharged molten polymer is thinned, and the thinned fibers move without substantially converging. Spray on the net conveyor,
It is separated from the gas stream on the net and laminated on the net. The laminated fibers are joined at their contact points by the heat of their own, forming a so-called web-like material.In this case, before cooling, pressurizing using a pressure roller to strengthen the joining, After cooling, heating and pressing are performed using a heating and pressing roller to strengthen the bonding. In any case, the web-like material having the fibers laminated and bonded between the fibers moves together with the net conveyor, and is then transferred from the net conveyor to another device for winding, and finally wound on a roller. Is taken.

It has been known from the laboratory that the nonwoven fabric obtained from the thermoplastic elastomer is very soft and has excellent stretchability. However, when this thermoplastic elastomer is used and is produced by the above-mentioned melt blow method, a sticking phenomenon occurs on the above-mentioned net conveyor or a production facility such as a moving means thereafter, and particularly for a weak meltblown nonwoven fabric having a small basis weight, the At present is that it cannot be obtained industrially stably.

In order to eliminate such inconvenience, the polymer itself is modified to be non-sticky,
Additives are added to the polymer to make it non-adherent, or for polymers that cannot be resolved by the formulation
A method such as spinning directly onto release paper or non-adhesive cloth by a melt blown method has been considered and manufactured. However, in any of the above methods, the excellent properties of the nonwoven fabric made of a single thermoplastic elastomer are reduced. That is, in the above, in the actual operation, it is merely a compromise between the production of the melt-blown non-woven fabric and the point that the property deterioration of the melt-blown non-woven fabric can be minimized and the adhesiveness can be prevented. In addition, the production cost is high, which is not preferable.

[0006] However, as the application development of the melt blown nonwoven fabric using the thermoplastic elastomer has been expanded, there is an increasing demand for the nonwoven fabric to exhibit its stretchability more.

[0007]

As described above, a melt-blown non-woven fabric made of a thermoplastic elastomer has a very good stretchability, but it is difficult to exfoliate it from a net conveyor at the time of melt-blow spinning. Therefore, there is still a problem that stable and stable production is required, and the emergence of a melt-blown nonwoven fabric having more excellent stretchability has been demanded. That is, an object of the present invention is to obtain a stretchable melt-blown nonwoven fabric and a method for producing the same, which overcome the above problems and demands.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies on a melt-blown nonwoven fabric made of a thermoplastic elastomer and a method for producing the same to solve the above-mentioned problems. However, the component (A) consisting of a thermoplastic elastomer which has adhesive properties during production of a nonwoven fabric but has very excellent elasticity is used. It has been found that by using a core-sheath type conjugate fiber wrapped in (1), the problem of stickiness during the production of the nonwoven fabric can be overcome, and a nonwoven fabric capable of maximizing its elasticity can be obtained.

That is, the nonwoven fabric invention of the present invention is characterized in that the fibers constituting the meltblown nonwoven fabric are composed of a core of a sticky component (A) made of a thermoplastic elastomer, and a component made of a thermoplastic elastomer but made non-sticky. A high-performance elastomeric meltblown nonwoven fabric having improved adhesiveness, characterized by being a core-sheath composite fiber having (B) a sheath portion. Here, the adhesive component (A) is a component that causes the collected web to adhere to a manufacturing facility such as a collecting net when the component (A) alone is melt-blown and spun. The sticky component (B) is a component that when the component (B) alone is melt-blown, the collected web does not substantially stick to manufacturing equipment such as a collecting net.

The invention also relates to a method for producing a nonwoven fabric according to the present invention, wherein the adhesive component (A) comprising a thermoplastic elastomer which adheres to a production facility such as a collecting means at the time of melt-blow spinning, Non-sticking component (B) for manufacturing equipment such as collection nets
A high performance elastomeric meltblown nonwoven fabric with improved adhesiveness, characterized by melt-blowing by a conventional method using a composite spinneret in which the former (A) component is a core and the latter (B) component is a sheath. It is a manufacturing method of.

In the present invention, the melt-blown non-woven fabric (ie, generally, a melt-blown non-woven fabric having excellent stretch properties) made of a thermoplastic elastomer and having the adhesive component (A) has excellent stretch properties. In order to substantially avoid lowering and to prevent sticking to the meltblowing production equipment, the sticking component (A) was surface-coated with a component (B) also made of a thermoplastic elastomer but made non-sticking. By melt-blowing as a core-sheath type conjugate fiber, the resulting melt-blown nonwoven fabric maximizes its stretch characteristics, and solves the inconvenience of passing during manufacturing and releasing during unwinding. It was done.

The thermoplastic elastomer used in the present invention is not particularly limited, such as styrene-based or urethane-based elastomers. However, in the case of urethane-based elastomers, any known melt-spinnable elastomer can be used. Can be. More preferred are polyester diols obtained by condensation polymerization of low molecular weight diols and dicarboxylic acids, polylactone diols obtained by ring-opening polymerization of lactams, polyoxyalkylene glycols, and polyalkylene carbonate glycols having an average molecular weight of 500 to 30.
It is a thermoplastic polyurethane obtained by reacting a polymer glycol of No. 00 with an organic diisocyanate and a low molecular compound having two active hydrogen atoms.

Particularly preferred thermoplastic polyurethanes are aliphatic or alicyclic diols having 2 to 12 carbon atoms, for example, ethylene glycol, propane diol, 1,4-butanediol, 1,5-pentanediol, 3- At least one selected from linear or side-chain aliphatic diols or alicyclic diols such as methyl-1,5-pentanediol and neopentyl glycol;
Obtained by reacting l kinds of diols with aliphatic dicarboxylic acids, for example, succinic acid, glutaric acid, adipic acid, or at least one kind of dicarboxylic acids or esters thereof selected from esters of these dicarboxylic acids and the like. Polyester diols having an average molecular weight of 600 to 3000 and organic diisocyanates such as phenylene diisocyanate, tolylene diisocyanate, 4,4
'A chain extension selected from an organic diisocyanate mainly composed of an aromatic or alicyclic diisocyanate such as diphenylmethane diisocyanate and a low molecular weight compound having two active hydrogen atoms, for example, diol, amino alcohol, hydrazine, diamine, etc. The agent is selected in a desired composition ratio, and polymerized by a melt polymerization method, a bulk polymerization method, a solution polymerization method, or the like to obtain a thermoplastic polyurethane.

In order to obtain a melt-blown nonwoven fabric having good uniformity, the thermoplastic polyurethane should have a content of the polymer diol serving as a soft segment of 45 to 75% by weight in the composition at the time of polyurethane production. preferable. The chain extender is a polyurethane polymerized using a chain extender mainly composed of a compound selected from a low molecular weight aliphatic diol or isophoronediamine, and has an intrinsic viscosity [η] of 0.5 to 0.5.
It is preferable to adjust the degree of polymerization so as to be in the range of 1.5 d1 / g. When the content of the soft segment in the polyurethane is less than 45% by weight, it is good in terms of spinnability and ultrafine fibers, but in terms of softness, stretchability, shape stabilization, and surface smoothness of the nonwoven fabric. Is not preferred. On the other hand, when the content of the soft segment is more than 75% by weight, the nonwoven fabric is good in terms of flexibility, but the spinnability and ultrafine fibers are deteriorated, and a nonwoven fabric with good formation cannot be obtained. On the other hand, if the intrinsic viscosity [η] of the polyurethane is small, sufficiently thin fibers cannot be obtained, and a meltblown nonwoven fabric of fibers having an uneven thickness is obtained. On the other hand, when the intrinsic viscosity [η] of the polyurethane is large, the melt viscosity becomes high, and a good fiber flow cannot be formed.

If the thermoplastic elastomer as described above is melt-blown and spun, the resulting melt blown nonwoven fabric has excellent stretchability, but has sticking to the manufacturing equipment, and even if obtained in a laboratory, However, in industrial production, the operation is impossible.

In the present invention, the melt-blown nonwoven fabric is composed of a composite ultrafine fiber having a structure in which the adhesive component (A) is covered with the non-adhesive component (B). It is important that the component (B) which is not present is also a stretchable component made of a thermoplastic elastomer like the component (A) in order to exhibit the stretchability of the adhesive component (A). For this purpose, it is necessary to convert the adhesive component (A) made of the thermoplastic elastomer into a component (B) having no adhesiveness.

One method for converting the adhesive component (A) made of a thermoplastic elastomer into the component (B) having no adhesiveness is as follows:
The purpose can be achieved by, for example, adding an anti-blocking agent to the thermoplastic elastomer adhesive component (A). As the antiblocking agent, a higher fatty acid bisamide, a montanic acid ester, or a mixture of a montanic acid ester and a montanic acid metal salt is preferable.

The higher fatty acid bisamide has 14 to 3 carbon atoms.
Produced from saturated higher fatty acids of up to 5 and aliphatic diamines of up to 1 to 10 carbon atoms. Examples of the higher fatty acids include, for example, myristic acid, pentadecylic acid, balmitic acid,
Heptadecyl acid, montanic acid and the like can be mentioned. Examples of the aliphatic diamine include methylene diamine, ethylene diamine, trimethylene diamine, and tetramethylene diamine. Among the higher fatty acid bisamides derived from the higher fatty acids and the aliphatic diamines, methylene bisstearic acid amide, tetramethylene bisstearic acid amide, ethylenebismontanamide, tetramethylenebismontanamide, and the like are preferable. More preferred are methylene bisstearic acid amide and ethylene bisstearic acid amide.

The montanic acid ester has a chain length of C2O.
To a C35 linear saturated carboxylic acid mixture and an ester obtained by reacting with a polyhydric alcohol such as ethylene glycol or propylene glycol, wherein the metal montanic acid salt is montanic acid and a metal belonging to the I-III group of the periodic law, For example,
Metal salts such as lithium, sodium, potassium, and aluminum.

The amount of the antiblocking agent is preferably in the range of 0.3 to 2.0% by weight, more preferably 0.7 to 1.5% by weight, based on the thermoplastic elastomer used. Range.

In the above description, the use of an anti-blocking agent has been described as a method for converting the non-sticky component (B) from the sticky component (A).
Without using the inhibitor, a thermoplastic elastomer itself may be modified to make it non-adhesive, and the elastomer may also be an elastomer (C) different from the elastomer of the adhesive component (A). There may be. However, since this kind of non-sticking modified elastomer usually has a deteriorated stretch property, it is desirable to use an elastomer having as excellent stretch property as possible as long as non-stick property can be obtained.

In the present invention, the heat-melted product of the adhesive component (A) and the non-adhesive component (B) composed of the above-mentioned thermoplastic elastomer is used as the core of the ultrafine fiber constituting the resulting melt blown nonwoven fabric. (A) / (B) in a weight ratio of (A component) / pod (B component) is from 95/5 to 50.
/ 50, preferably in a composition range satisfying 90/10 to 70/30, to the melt-blown composite spinneret, and perform composite melt-blow spinning by a conventional method.

Such a composite melt-blow spinning method comprises, for example, a composite hole comprising a central hole serving as a discharge portion of the component (A) and an annular hole of the component (B) surrounding the central hole of the component (A). Using a composite spinneret in which units are arranged in a line, the above-mentioned molten components (A) and (B) are supplied to the spinneret from respective extruders, and the melt extruded from the spinneret is subjected to high-speed hot air Into fine fibers, which can be obtained by depositing and collecting them on a collecting conveyor.

The collected web fibers are adhered by the heat of the ultrafine fibers themselves during melt blown spinning. However, if necessary, after collection, pressure bonding may be performed by hot-pressing means such as a hot embossing roll.

[0025]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 This is an example in which the following thermoplastic polyurethane resin is used as a raw material polymer for the core portion and the sheath portion to form a stretchable melt-blown nonwoven fabric made of core-sheath type ultrafine fibers. Core: polymethylpentane adipate polyol and 4,
4'-diphenylenemethane diisocyanate and 1,
A polyester-based polyurethane resin (A) composed of 4-butanediol was used. This polyurethane resin (A) is adhesive. Sheath: A resin composition (B) obtained by adding 1.0% by weight of a higher fatty acid bisamide as a blocking agent to the polyurethane resin (A) was used. This resin composition (B) is non-adhesive. The above core-sheath resin component is used as a raw material and melt-blown using a core-sheath type melt blow die nozzle to obtain a core-sheath type composite ultrafine fiber having a core / sheath weight ratio of 90/10.
A 0 g / m ² stretchable polyurethane meltblown nonwoven was obtained. Table 1 shows the recovery physical properties of this nonwoven fabric after 100% elongation.
Shown in

Example 2 The weight ratio of the core and the sheath was 70 /
In the same manner as in Example 1 except that the weight was 30 and the basis weight was 60 g.
/ M ² of a stretchable polyurethane meltblown nonwoven fabric. Table 1 shows the recovery properties of this nonwoven fabric after 100% elongation.

Example 3 The weight ratio of the core and the sheath was 50 /
The same method as in Example 1 except that the weight was 50, the basis weight was 60 g.
/ M ² of a stretchable polyurethane meltblown nonwoven fabric. Table 1 shows the recovery properties of this nonwoven fabric after 100% elongation.

Comparative Example 1 An elastic polyurethane melt blown nonwoven fabric having a basis weight of 60 g / m ² was obtained using a non-adhesive polymer as a raw material for the sheath portion of Example 1 and using a normal melt-blow die which was not a core-sheath type. . 100% of this nonwoven
Table 1 shows the recovery properties after elongation.

[0030]

[Table 1]

As shown in Table 1, when comparing the ratio (Y) / (X) between the 50% recovery stress and the 50% elongation stress, which are used as indices representing the expansion and contraction characteristics, it can be seen that in Examples 3 to 1, As the weight ratio of the core component, which is a sticky resin component having excellent stretchability, increases, the (Y) / (X) value increases, indicating better stretchability. In addition, comparing Comparative Example 1 of the melt blown nonwoven fabric formed only with the non-adhesive resin component forming the sheath component and Examples 1 to 3 made of ultrafine fibers having a core-in-sheath type composite structure, all Examples are comparative examples. 1
The values of (Y) / (X) are larger than those of the examples, and the values of residual strain are smaller in each of the examples, indicating excellent stretchability.

[0032]

According to the present invention, the adhesive component (A) made of a thermoplastic elastomer, which exhibits its excellent elasticity, is replaced by the component (B) made of a thermoplastic elastomer but made non-adhesive. The melt-blown non-woven fabric obtained by melt-blowing as a core-sheath type composite fiber with the surface coated in the above) can exhibit its stretchability to the maximum, and as a production method, there is no problem in permeability during production, In addition, winding and rewinding can be performed stably, thereby enabling industrially stable production. That is, the present invention is useful in practice as a thermoplastic elastomeric meltblown nonwoven itself and as a method for producing the same. Such an elastomeric meltblown nonwoven fabric of the present invention can be suitably applied to, for example, a back sheet or a waist member of a diaper by utilizing its properties. Etc. can be suitably applied.

Claims (6)

[Claims] The fibers constituting the melt blown nonwoven fabric are:
It is a core-sheath type composite fiber having a core made of the adhesive component (A) made of a thermoplastic elastomer and a sheath made of the component (B) made of the thermoplastic elastomer but made non-adhesive. High performance elastomeric meltblown nonwoven fabric with improved stickiness. Here, the adhesive component (A) is a component that causes the collected web to adhere to a manufacturing facility such as a collecting net when the component (A) alone is melt-blown and spun. The sticky component (B) is a component such that when the component (B) is melt-blown, the collected web does not substantially stick to manufacturing equipment such as a collecting net. 2. The component (B) is a component obtained by blending an anti-blocking agent with an adhesive component (C) made of a thermoplastic elastomer different from the component (A) or the component (A). The melt-blown nonwoven fabric according to claim 1, characterized in that: 3. The core-sheath type composite fiber according to claim 1, wherein the weight ratio of the core / sheath component of the fiber satisfies the range of 95/5 to 50/50. 3. The melt blown nonwoven fabric according to 1. 4. An adhesive component (A) made of a thermoplastic elastomer which sticks to a manufacturing facility such as a collecting net during melt-blow spinning, and a non-sticking component which is also made of a thermoplastic elastomer but is manufactured at a manufacturing facility such as a collecting net during melt blow spinning. The adhesiveness is improved by melt-blowing the component (B) which has been made into a melt by using a composite spinneret in which the former (A) is a core and the latter (B) is a sheath. For producing a high-performance elastomeric meltblown nonwoven fabric. 5. The component (B) is a component obtained by blending an anti-blocking agent with an adhesive component (C) made of a thermoplastic elastomer different from the component (A) or the component (A). The method for producing a melt-blown nonwoven fabric according to claim 4, characterized in that: 6. The core / sheath type composite fiber according to claim 4, wherein the weight ratio of the core / sheath component of the fiber satisfies the range of 95/5 to 50/50. 3. The method for producing a melt blown nonwoven fabric according to item 1.