JP3055640B2 - Nonwoven fabric and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is suitable for sanitary materials such as base cloths for cataplasms, plaster base cloths, bandages, supporters, simple masks, etc., clothing materials such as interlining for clothing, and cotton in clothing. It relates to a non-woven fabric having good elasticity.

[0002]

2. Description of the Related Art Conventionally, a stretchable nonwoven fabric has been used for a base cloth for cataplasms, a base cloth for plaster, a bandage, or a cotton pad for ski wear so as to easily follow the movement of the body. I was These conventional elastic nonwoven fabrics
Uses so-called latently crimpable fibers whose number of crimps increases by heating. After forming a nonwoven fabric, the latently crimped fibers of the latently crimpable fibers are expressed by heating under no tension or low tension. Thus, a fiber having a coiled crimp is produced in the nonwoven fabric, and the nonwoven fabric is given elasticity by utilizing the spring-like behavior of the fiber (Japanese Patent Laid-Open No. 2-12).
7553, JP-A-3-213556).

However, recently, in the field of base cloth for cataplasms and insulated cotton for ski wear, the demand for thin materials has increased, and conventional latently crimpable fibers have thick fibers and voids between the fibers. However, there is a problem that a space penetrating in the thickness direction of the cloth is formed. That is, in the case of a thick material, the space penetrating the cloth is closed by laminating the fibers in the thickness direction, but in the case of a thin material, the space remains without being closed. If there is such a space, for example, in the case of a base cloth for a cataplasm, there is a problem that the medicine escapes to the back side, and in the case of insulated cotton, warm air can be retained inside the nonwoven fabric because air movement occurs. A problem that sufficient heat retention cannot be obtained.

On the other hand, in the field of nonwoven fabrics, as a means for obtaining a dense structure with small voids by making the constituent fibers of the nonwoven fabric thin, a technique of using splittable conjugate fibers as constituent fibers is known (Japanese Patent Publication No. Sho 52). No.-30629, Japanese Patent Publication No. 5
3-37456). However, since the ultrafine fibers formed by splitting the conventional splittable conjugate fibers are each composed of a single component, the nonwoven fabric formed therefrom is dense and excellent in strength, but has little elongation and is not stretchable. The sex was poor.

[0005] In order to obtain a non-woven fabric having both denseness and elasticity, the two components A and B having a bonding property have a bimetal structure, and this is divided into a structure in which the components A and B are combined with a separable C component. A nonwoven fabric made using a type composite fiber has been proposed (Japanese Patent Application Laid-Open No. 54-147269). When the splittable conjugate fiber is split, the two components A and B are separated into an ultrafine fiber having a bimetal structure and an ultrafine fiber consisting of the C component. Since the split ultrafine fibers of the A and B2 components have latent crimping properties, their expression increases the number of crimps. Therefore, the nonwoven fabric using this splittable conjugate fiber is a conventional split nonwoven fabric. It is more elastic than non-woven fabrics using type composite fibers. However, even in this nonwoven fabric, since the ultrafine fiber composed of the component C has no latent crimping property, the fiber inhibits the elongation of the nonwoven fabric, so that sufficient elasticity cannot be obtained.

[0006] In the nonwoven fabric using the above-mentioned three-component splittable conjugate fiber, if only the component C is extracted and removed with a specific solvent, the nonwoven fabric can be formed using only the ultrafine fibers composed of the A and B2 components having latent crimpability. Since it can be configured, a nonwoven fabric having high elongation and high elasticity can be obtained. But,
When the C component is extracted and removed, voids corresponding to the volume of the C component are generated by the removal of the C component, so that there is a problem that it is difficult to make the material dense and that the nonwoven fabric is easily debris. In addition, this means has a drawback that the process for removing the C component is complicated, and that a treatment of a solvent for removing the C component is also required, which increases the production cost.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and has a dense structure composed of ultrafine fibers obtained by dividing a splittable conjugate fiber. An object of the present invention is to provide a nonwoven fabric having high elongation and high elasticity.

[0008]

According to the present invention, there is provided a nonwoven fabric comprising ultrafine fibers A and ultrafine fibers B obtained by subjecting a splittable conjugate fiber to a splitting process. The present invention provides a nonwoven fabric characterized in that the ultrafine fibers B are each composed of two kinds of resins having different heat shrinkage rates and exhibit latent crimp.

Further, the present invention has a cross-sectional structure in which segments A and B which can be divided are alternately arranged,
And a step of forming a nonwoven fabric by using a splittable conjugate fiber in which each of the segments A and B is composed of two kinds of resins having different heat shrinkage rates; a step of splitting the splittable conjugate fiber; Heat-treating the ultrafine fibers A and the ultrafine fibers B to develop latent crimps.

The splittable conjugate fiber used in the present invention has a cross sectional structure in which segments A and segments B which can be split are alternately arranged, and each of the segments A and B has two types of heat shrinkage ratios. Fibers composed of different resins are used. That is, the splittable conjugate fiber used in the present invention is physically or chemically split to obtain an ultrafine fiber A composed of the segment A and an ultrafine fiber B composed of the segment B. Any of the fibers B can exhibit crimp by heat treatment. As such a splittable conjugate fiber, for example, there is a fiber having a cross-sectional structure as shown in FIGS. 1 to 9 also show the cross-sectional structures of the ultrafine fibers A and B obtained by dividing each fiber.

The fibers shown in FIGS. 1 to 5 are composed of four types of resin components, and the segments A and B are each composed of two types of resin components. The two types of resin components forming the segment A and the two types of resin components forming the segment B have high affinity, and the resins of the segment A and the segment B have low affinity so that they can be separated from each other. It is desirable to make such a combination. When the resin combination is made in this manner, the segment A and the segment B are easily divided by the dividing process. For example, in the fibers of FIGS. As a result, in the fiber shown in FIG. 5, ultrafine fibers A and B having a structure in which one resin surrounds the other resin are obtained. In order to impart latent crimpability to the fiber of FIG. 5, it is necessary that the center of the outer resin and the center of the inner resin have an eccentric structure in which the center is shifted. In the present invention, two types of resins having different heat shrinkage rates are used in each segment. For this reason,
The ultrafine fibers A and B obtained by the division are bent by the heat shrinkage difference by heat treatment, so that latent crimps can be developed.

The resin component constituting the splittable conjugate fiber is not particularly limited, but for example, polyethylene (PE),
Polyolefin resins such as polypropylene (PP) or copolymerized polyolefins containing them as a main component,
Polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT) or copolymerized polyesters containing these as a main component, nylon 6, nylon 66, condensation-polymerized polyamide of aromatic diamine and aromatic dicarboxylic acid, or those Polyamide-based resins such as polyamide whose main component is a polyacryl-based resin, and the like can be used. As the combination of the resin components of the segment A and the segment B, a combination of a polyester-based resin and a polyolefin-based resin, and a combination of a polyester-based resin and a polyamide-based resin are suitable because they have low affinity and are easily divided. In each segment, it is desirable to combine resins of the same type. For example, a polyolefin resin is a polyester resin such as PP and PE, an olefin copolymer containing PP and PP as a main component, and the like. In the case of a polyamide resin such as PET and copolyester, it is preferable to select a combination of resin components having high affinity and different heat shrinkage ratios such as nylon 66 and copolyamide. Of course, the combination of resin components is not limited to the above, and different types of resins may be combined in the same segment. The combination of resin components can be divided into segment A and segment B by a division process,
In addition, in each segment, it is only necessary that the two kinds of resin components have a combination capable of providing latent crimpability without being divided. In addition, since the ultrafine fibers A and the ultrafine fibers B obtained by the division are desirably capable of simultaneously developing latent crimp by heat treatment, the low melting point resin component of each segment is selected from those having a softening point or a melting point close to the range. It is desirable.

The fibers shown in FIGS. 6 to 8 are composed of three types of resin components, and the segment A and the segment B are each composed of two types of resin components, one of which is common to the segments A and B. A resin component is used. In the case of these fibers, it is desirable to select a resin having a low affinity between portions where both segments are in contact with each other so that segment A and segment B can be divided. Therefore, in each segment, it is desirable that the resin component common to both segments has a structure surrounded by the other resin component. However, when the resin component common to both segments is dispersed in the other resin of each segment in an island shape as in the case of the fiber of FIG. 8, some of the islands are located in the portion where both segments are in contact. However, it can be used because it does not substantially hinder the segment division. In the case of the fiber of FIG. 6, if the affinity of the resin component common to both segments and the resin of each segment is low, the segment may be further divided in the segment and an ultrafine fiber having latent crimpability may not be obtained. There is. Therefore, in the fiber of FIG. 6, the affinity between the resin component common to both segments and the other resin component of each segment is high, and the affinity of the other resin component of each segment is low. It is necessary to select a combination of resin components. 7 and 8, since the common resin component is surrounded by the other resin component, the combination of the resin components is set so that the affinity between the non-common resin components of each segment becomes low. I just need.

When the fibers shown in FIGS. 6 to 8 are subjected to a splitting process, the fibers shown in FIG. 6 yield ultrafine fibers A and B having a structure in which two kinds of resins are bonded to each other, and the fibers shown in FIG. Ultrafine fibers A and B having a structure are obtained, and the ultrafine fibers A and B having a sea-island structure are obtained from the fibers in FIG. However, the distribution of the island components of the ultrafine fibers obtained by dividing the fibers in FIG. 8 needs to be offset. This is because if the island components are uniformly distributed, it is difficult to obtain latent crimpability. In the present invention, two kinds of resins having different heat shrinkage rates are used for the two kinds of resins in each segment.
For this reason, since the ultrafine fibers A and B obtained by the division are bent by the heat shrinkage difference by heat treatment, latent crimp can be developed.

The resin component constituting the three-component splittable conjugate fiber is not particularly limited as in the case of the four-component resin, and polyolefin resins, polyester resins, polyamide resins, polyacryl resins and the like can be used. Can be used.
As a combination of segment A and segment B of a resin component not common to each segment, for example, a combination of a polyester-based resin and a polyolefin-based resin, a combination of a polyester-based resin and a polyamide-based resin is preferable because of low affinity and easy division. On the other hand, as a resin component common to each segment, polystyrene, PE, copolymerized polyolefin, copolymerized polyester and the like are suitable. In addition, since the ultrafine fibers A and the ultrafine fibers B obtained by the division are desirably capable of simultaneously developing latent crimp by heat treatment, the low melting point resin component of each segment is selected from those having a softening point or a melting point close to the range. It is desirable. In the case of the three-component splittable conjugate fiber, if the resin component common to each segment is a low melting point resin component, the softening point or the melting point may be the same.

[0016] The three-component splittable conjugate fiber is the same as that of the aforementioned four-component split conjugate fiber.
Compared to component-based splittable conjugate fibers, the number of resin components is small, so there is an advantage that nozzle design is easy and mass production is easy.On the other hand, since a resin component common to both segments is used, the combination of resins Is narrow, and the arrangement of the resin components in each segment may be limited.

The fiber shown in FIG. 9 is composed of two types of resin components.
Each segment has an eccentric structure, and the resin component inside the A segment and the resin component outside the B segment are the same, and the resin component inside the B segment and the resin component outside the A segment are the same. Therefore, in order to make the fiber of FIG. 9 easier to split, it is desirable to use two kinds of resin components having low affinity with each other. In the case of forming a splittable conjugate fiber only with two types of resin components, if the arrangement of the resin components in each segment has a parallel bonding structure, division occurs in each segment, and
Since ultrafine fibers composed of the components cannot be obtained and the latent crimpability cannot be imparted, the arrangement of the resin components in each segment needs to be such that one resin surrounds the other resin. As a combination of two kinds of resins, for example, a combination of a polyester resin and a polyolefin resin, or a combination of a polyester resin and a polyamide resin is preferable because of low affinity and easy division.

Although the splittable conjugate fibers shown in FIGS. 1 to 9 are each divided into four, the number of divisions is not limited to this. It may be something. Also, the number of resin components, the arrangement of each resin component, or the cross-sectional structure, the fibers can be split, and the split fibers are composed of two components having different heat shrinkage ratios, and have a potential crimpability. Anything can be designed. Furthermore, in order to further reduce the fiber diameter of the ultrafine fibers obtained by division, the fibers may be hollow.

The steps of forming the nonwoven fabric of the present invention include:
Known nonwoven fabric forming processes can be used, for example, a mechanical entanglement method such as a hydroentanglement method, a needle punch method, a stitch bond method, an adhesive bonding method such as a dipping method, a spray method, a spun bond method, a wet method, etc. Can be used alone or in combination. Among these, in the process by the water entanglement method, the needle punch method, or the like, the splitting process of the splittable conjugate fiber can be performed at the same time in the process of entangling the fibers. According to this step, not only the splittable conjugate fiber is split but also a dense structure in which the ultrafine fibers A and the ultrafine fibers B obtained by the splitting are entangled is obtained. In addition, in this nonwoven fabric forming step, the adhesive is not substantially used, so that the fibers are not completely fixed at the bonding points, and a certain degree of movement of the fibers is allowed, so that a nonwoven fabric with high elongation and high elasticity can be easily obtained. Furthermore, when used for sanitary materials such as base cloth for cataplasms, there is no need to worry about the influence of the adhesive on the skin because no adhesive is used.

The step of dividing the splittable conjugate fiber may be performed together with the step of forming the nonwoven fabric as in the above-described hydroentanglement method or the needle punch method, or may be performed after the formation of the nonwoven fabric. The splitting method may be any method as long as the splittable conjugate fiber can be split into the segment A and the segment B. A method of dividing by utilizing a difference in heat shrinkage ratio and a method of swelling a resin with a specific solvent and dividing by utilizing the difference in swelling ratio are suitable.
In particular, a method in which the fibers are entangled by water entanglement (water punch) or needle punch, and at the same time, a mechanical impact is applied to the fibers to separate the fibers, can reduce the number of steps, and furthermore, the dense and highly entangled fibers This is because a nonwoven fabric having a structure can be obtained.

The splitting of the splittable conjugate fiber may be performed twice or more. For example, after splitting by mechanical impact together with a nonwoven fabric forming step by hydroentanglement, latent crimps of the ultrafine fibers A and B are developed. In the heat treatment step, the segments A and B remaining undivided may be further divided by utilizing the difference in the heat shrinkage.

It is desirable that the splittable conjugate fiber is completely split into segments A and B in this splitting process to form ultrafine fibers A and B. May be left undivided.
On the other hand, if the dividing conditions are severe, the ultrafine fibers obtained by the division may be further divided into two components, but it is difficult to completely control the ultrafine fibers. Fibers may be partially contained. However, it is desirable that the undivided portion and the single component ultrafine fiber are removed as much as possible.

The ultrafine fibers A and the ultrafine fibers B obtained by splitting the splittable conjugate fiber are each composed of two types of resin components having different heat shrinkage rates. Crimp is developed and the number of crimps increases. Thereby, the nonwoven fabric is densified and elasticity is imparted. In addition, it is preferable that the heat treatment for developing the latent crimps of the ultrafine fibers A and B be performed under no tension or under low tension, and it is better to perform the heat treatment in a state that allows the nonwoven fabric to shrink with the crimping of the fibers. . If the non-woven fabric is subjected to a heat treatment in a state where a large tension is applied, the fibers may not sufficiently exhibit crimp, or the distribution of the fibers may be uneven. As an apparatus for performing a heat treatment in a state in which tension is not applied as much as possible, there is an apparatus for conveying and heating a nonwoven fabric while supporting it with hot air blown from above and below.

The nonwoven fabric of the present invention thus obtained is
The splittable conjugate fiber is composed of ultrafine fibers A and B formed by splitting, and each of the ultrafine fibers A and B expresses a potential crimp and is in a highly crimped state. For this reason, the nonwoven fabric of the present invention can have a dense structure with a small fiber gap, and can be deformed by the crimp of the microfine fiber being stretched when an external force acts, so that a large elongation can be obtained. Further, when the external force is removed, the ultrafine fibers tend to return to the original crimped state, and thus have excellent stretchability. Furthermore,
Since the non-woven fabric is composed of very thin fibers, it has a soft touch and fits easily on the skin.

The nonwoven fabric of the present invention can be combined with stretchable fabrics, knits, nets, yarns, films, etc.
They may be bonded together. When combined with a stretchable woven fabric or net, not only can the strength be improved, but when the woven fabric or net reaches the limit of elongation, the elongation stops exactly, so elongation by a predetermined elongation, such as a bandage It is suitable for applications that require In particular, woven fabrics, knits, nets, and yarns are composed of the splittable conjugate fibers used in the present invention, are combined with the splittable conjugate fibers that constitute the nonwoven fabric, are subjected to splitting treatment by hydroentanglement, etc. In this case, a composite nonwoven fabric which can be integrated in a very tightly and densely entangled state and has elasticity can be obtained.

[0026]

【Example】

Example 1 As a resin component constituting the A segment, a relative viscosity η was used.
_rel 0.65 PET and a polyester copolymer having a relative viscosity η _rel 0.62 containing PET as a main component (melting point 180
° C), and as a resin component constituting the B segment, PP of MFR40 and MFR30 containing PP as a main component.
(Melting point 135 ° C.) is used. First, each resin is measured in a molten state by a gear pump and sent to a spinning head. The resin is spun at 290 ° C. in a cross-sectional structure shown in FIG. A splittable conjugate fiber was obtained. 8 after 5 hours of spinning
It is stretched about 3 times in hot water at 0 ° C, treated with an oil agent, mechanically crimped through a stuffer box, dried with hot air at 80 ° C, cut, and cut to a fiber length of 51 mm and a fineness of 3 denier. A staple of a four-component splittable composite fiber having a cross-sectional structure shown in FIG. 2 was obtained.

A fiber web having a basis weight of 40 g / m ² is formed by using a carding machine using the splittable conjugate fiber, and the fiber web is entangled with the fiber web under the condition of a water pressure of 70 kg / cm ² to entangle the fiber web. A split conjugate fiber is divided into an A segment composed of PET and a polyester-based copolymer and a B segment composed of PP and a polyolefin-based copolymer, and a hydroentangled nonwoven fabric composed of ultrafine fibers A and B I got Next, the hydroentangled nonwoven fabric is subjected to 130 under low tension.
It heat-processed at the temperature of ° C, and revealed the latent crimp of the ultrafine fibers A and B. The heat treatment promoted the division of the undivided portion of the splittable conjugate fiber.

The obtained nonwoven fabric had a basis weight of 80 g / m ² and a thickness of 0.6 mm, was dense, had a large elongation, and had excellent stretchability. In addition, since they are bonded by water entanglement, they do not contain an adhesive and most of the fiber oil is removed, so that they were extremely suitable for sanitary materials such as base cloth for cataplasms.

Example 2 As a resin component constituting the A segment, a relative viscosity η was used.
MFR30 with _rel 0.65 PET and PP as main components
Using a polyolefin-based copolymer (melting point 135 ° C.), and MFR4
The same polyolefin-based copolymer as that used for the 0 segment and the A segment is used. The resin component common to both the A and B segments is the core component of each segment. First, the molten state of each resin is measured by a gear pump and sent to the spinning head. The resin is spun at 290 ° C. in the cross-sectional structure shown in FIG. A splittable conjugate fiber was obtained.
Five hours after spinning, the film is stretched about three times in hot water at 80 ° C., treated with an oil agent and mechanically crimped through a stuffer box.
After being dried with hot air at ℃, it was cut to obtain a staple of a three-component splittable composite fiber shown in FIG. 7 having a fiber length of 51 mm and a fineness of 2.5 denier.

A fiber web having a basis weight of 40 g / m ² is formed by a carding machine using the above splittable conjugate fiber, and the fiber web is entangled under a condition of a water pressure of 70 kg / cm ² to entangle the fiber web. , A split-type conjugate fiber is divided into an A segment composed of PET and a polyolefin-based copolymer and a B segment composed of PP and a polyolefin-based copolymer, and a hydroentangled nonwoven fabric composed of ultrafine fibers A and B I got Next, the hydroentangled nonwoven fabric is subjected to 13
Heat treatment was performed at a temperature of 0 ° C. to develop latent crimps of the ultrafine fibers A and B. The heat treatment promoted the division of the undivided portion of the splittable conjugate fiber.

The obtained nonwoven fabric had a basis weight of 90 g / m ² and a thickness of 0.6 mm, was dense, had a large elongation, and had excellent stretchability. In addition, since they are bonded by water entanglement, they do not contain an adhesive and most of the fiber oil is removed, so that they were extremely suitable for sanitary materials such as base cloth for cataplasms.

[0032]

As described above, the nonwoven fabric of the present invention is composed of the fine fibers A and B obtained by dividing the splittable conjugate fiber, and each of the fine fibers A and B has two types of heat. It is made of resins having different shrinkage ratios, and by using this difference in the heat shrinkage ratios to develop latent crimps, it is in a highly crimped state.

For this reason, the nonwoven fabric of the present invention has a structure in which very fine fibers have a large number of crimps, and the fiber gap can be made small and dense. It stretches to obtain a large elongation. In addition, when the tension is removed, the fiber returns to the original crimped state, so that the fiber is also excellent in elasticity. Further, since the nonwoven fabric is made of very thin fibers, it has a soft touch and is easy to adapt to the skin.

In particular, when the splitting process of the splittable conjugate fiber is performed by mechanical entanglement means such as water entanglement or needle punching, the fiber can be split at the same time as the formation of the nonwoven fabric, so that the process can be streamlined. In addition, the nonwoven fabric formed by this method is a nonwoven fabric that is denser and superior in strength because the ultrafine fibers A and B are highly entangled with each other, and hardly causes fiber detachment. Moreover, since the nonwoven fabric formed by this method can be formed without including an adhesive or the like, it is suitable for a base material used for a human body, such as a sanitary material such as a base fabric for a poultice.

The nonwoven fabric of the present invention has a large elongation and elasticity. For this reason, for example, sanitary materials such as base cloth for cataplasms, plaster base cloth, bandages, supporters, simple masks, clothing interlining, and clothing inserts that require expansion and contraction following the movement of the human body Particularly suitable for clothing materials such as cotton and base materials for synthetic leather for clothing. Further, since the nonwoven fabric of the present invention has a dense structure, for example, when used for a base cloth for cataplasm, even if the thickness is small, the drug does not permeate to the other side and does not appear on the other side, and for clothing. When used for insulated cotton, etc., it is possible to retain warm air in the gaps even if the thickness is thin, so that it is excellent in heat retention. As described above, the nonwoven fabric of the present invention has excellent functions and is an extremely useful material that can be used for various applications.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a cross-sectional structure of a four-component splittable conjugate fiber used in the present invention, and a cross-sectional structure of ultrafine fibers A and B obtained by splitting the splittable conjugate fiber. FIG.

FIG. 2 is a schematic view showing an example of a cross-sectional structure of a four-component splittable conjugate fiber used in the present invention, and a cross-sectional structure of ultrafine fibers A and B obtained by splitting the splittable conjugate fiber. FIG.

FIG. 3 is a schematic view showing an example of a cross-sectional structure of a four-component splittable conjugate fiber used in the present invention, and a cross-sectional structure of ultrafine fibers A and B obtained by splitting the splittable conjugate fiber. FIG.

FIG. 4 is a schematic view showing an example of a cross-sectional structure of a four-component splittable conjugate fiber used in the present invention, and a cross-sectional structure of ultrafine fibers A and B obtained by splitting the splittable conjugate fiber. FIG.

FIG. 5 is a schematic view showing an example of a cross-sectional structure of a four-component splittable conjugate fiber used in the present invention, and a cross-sectional structure of ultrafine fibers A and B obtained by splitting the splittable conjugate fiber. FIG.

FIG. 6 is a schematic view showing an example of a cross-sectional structure of a three-component splittable conjugate fiber used in the present invention, and a cross-sectional structure of ultrafine fibers A and B obtained by splitting the splittable conjugate fiber. FIG.

FIG. 7 is a schematic view showing an example of a cross-sectional structure of a three-component splittable conjugate fiber used in the present invention, and a cross-sectional structure of ultrafine fibers A and B obtained by splitting the splittable conjugate fiber. FIG.

FIG. 8 is a schematic view showing an example of a cross-sectional structure of a three-component splittable conjugate fiber used in the present invention, and a cross-sectional structure of ultrafine fibers A and B obtained by splitting the splittable conjugate fiber. FIG.

FIG. 9 is a schematic diagram showing an example of a cross-sectional structure of a bicomponent splittable conjugate fiber used in the present invention, and a cross-sectional structure of ultrafine fibers A and B obtained by splitting the splittable conjugate fiber. FIG.

Claims (4)

(57) [Claims] 1. A nonwoven fabric comprising ultrafine fibers A and ultrafine fibers B obtained by dividing a splittable conjugate fiber, wherein the ultrafine fibers A and the ultrafine fibers B are two types of resins each having a different heat shrinkage. And a non-woven fabric characterized by exhibiting latent crimp. 2. The nonwoven fabric according to claim 1, wherein the ultrafine fibers A and the ultrafine fibers B are entangled. 3. A segment A and a segment B which can be divided.
And a step of forming a nonwoven fabric using a splittable conjugate fiber composed of two types of resins having different heat shrinkage ratios, each having a cross-sectional structure in which the segments A and B are alternately arranged. A method for producing a nonwoven fabric, comprising: a step of dividing a splittable conjugate fiber; and a step of subjecting the ultrafine fibers A and the ultrafine fibers B obtained by the division to heat treatment to develop latent crimp. 4. The split conjugate fiber is divided by a mechanical entanglement means such as a water entanglement or a needle punch, and the divided ultrafine fiber A and the ultrafine fiber B are entangled. Production method of nonwoven fabric.