JP6776018B2 - Granular cotton molded product and its manufacturing method - Google Patents

Description

The present invention relates to various batting materials used for clothing and bedding, fiber aggregates that can be used as cushioning materials, cushioning materials, etc., and more specifically, a granular cotton molded product obtained by molding granular cotton and its production. Regarding the method.

Conventionally, non-woven fabrics, hard cotton materials, rubber, sponges, urethane materials, air cushioning materials and the like have been known as batting materials, cushioning materials and cushioning materials used for clothing products, bedding products, furniture and packaging materials. ing. Further, new cushioning materials and cushioning materials having excellent feel, texture, handleability and the like are required.

On the other hand, as a batting material for clothing or bedding products, granular cotton (also referred to as "grain cotton", "fiber ball" or "ball-shaped cotton") in which fibers are aggregated and / or molded into particles has been proposed (also referred to as "grain cotton", "fiber ball" or "ball-shaped cotton"). For example, see Patent Documents 1 to 3). Further, various methods for producing granular cotton have also been proposed (see, for example, Patent Documents 4 to 6). However, all of these only propose the granular cotton itself and its manufacturing method.

JP-A-2002-138358 Japanese Unexamined Patent Publication No. 2001-08962 Japanese Unexamined Patent Publication No. 2015-155586 Japanese Unexamined Patent Publication No. 03-206125 Japanese Unexamined Patent Publication No. 2003-183969 Japanese Unexamined Patent Publication No. 2001-295170

There is a demand for a new molded product that can be used as various batting materials, cushioning materials, cushioning materials, etc., and more preferably, a new molded product that is excellent in feel, texture, handleability, and the like.

The present inventors prepare granular cotton, fill it in a mold having a certain space so that the granular cotton is dense enough to come into contact with each other, and cause three-dimensional crimping to occur in the fibers at the contact portion between the granular cotton and the granular cotton. As a result, it was found that the fibers that developed three-dimensional crimping at the contact portion were entangled with the adjacent granular cotton and integrated with each other without adhering to each other to form a granular cotton molded body. We have found that such a granular cotton molded product is preferably excellent in feel, texture, handleability, etc., and have completed the present invention.

That is, in one gist, the present invention is a granular cotton molded product in which the fibers constituting the granular cotton are entangled with each other without being adhered to each other.
Provided is a granular cotton molded product in which three-dimensional crimps are expressed in at least a part of fibers constituting the bonded portion in a joint portion between granular cottons constituting the granular cotton molded product.

Since the present invention has the above-mentioned characteristics, it is preferable to provide a novel granular cotton molded product having excellent feel, texture, handleability and the like.

The "three-dimensional crimp" of the fiber is schematically shown. A crimp with a curved peak as shown in FIG. 1A (also referred to as "wave-shaped crimp"), and a crimp with a spirally curved peak as shown in FIG. 1B ("spiral crimp" or "coil"). (Also referred to as “like crimp”), as shown in FIG. 1C, a crimp in which a wavy crimp and a spiral crimp are mixed can be exemplified. A crimp in which "mechanical crimp" and at least one of wavy crimp and spiral crimp are mixed is schematically shown. This mixed crimp is also included in the three-dimensional crimp. A "mechanical crimp" in which the peak (or peak) of the crimp is an acute angle is schematically shown. A scanning electron microscope (SEM) photograph (10 kV, 30 times) of a granular cotton molded product (Example 1) obtained by heat-treating the granular cotton of fiber 1 at 100 ° C. for 10 minutes is shown. The SEM photograph (10 kV, 200 times) of the molded article of FIG. 4A is shown. An SEM photograph (10 kV, 30 times) of a granular cotton molded product (Example 2) obtained by heat-treating the granular cotton of fiber 1 at 105 ° C. for 10 minutes is shown. The SEM photograph (10 kV, 200 times) of the granular cotton molded article of FIG. 5A is shown. An SEM photograph (10 kV, 30 times) of a granular cotton molded product (Example 3) obtained by heat-treating the granular cotton of fiber 1 at 110 ° C. for 10 minutes is shown. The SEM photograph (10 kV, 200 times) of the granular cotton molded article of FIG. 6A is shown. An SEM photograph (10 kV, 30 times) of a granular cotton molded product (Comparative Example 1) obtained by heat-treating the granular cotton of the fiber 2 at 100 ° C. for 10 minutes is shown. The SEM photograph (10 kV, 200 times) of the granular cotton molded article of FIG. 7A is shown. An SEM photograph (10 kV, 30 times) of a granular cotton molded product (Comparative Example 2) obtained by heat-treating the granular cotton of the fiber 2 at 110 ° C. for 10 minutes is shown. The SEM photograph (10 kV, 200 times) of the granular cotton molded article of FIG. 8A is shown. An SEM photograph (10 kV, 30 times) of a granular cotton molded product (Comparative Example 3) obtained by heat-treating the granular cotton of the fiber 2 at 125 ° C. for 10 minutes is shown. The SEM photograph (10 kV, 200 times) of the granular cotton molded article of FIG. 9A is shown. An SEM photograph (10 kV, 30 times) of a granular cotton molded product (Comparative Example 4) obtained by heat-treating the granular cotton of fiber 1 at 80 ° C. for 10 minutes is shown. The SEM photograph (10 kV, 200 times) of the granular cotton molded article of FIG. 10A is shown. An SEM photograph (10 kV, 30 times) of a granular cotton molded product (Comparative Example 5) obtained by heat-treating the granular cotton of fiber 1 at 140 ° C. for 10 minutes is shown. The SEM photograph (10 kV, 200 times) of the granular cotton molded article of FIG. 11A is shown.

The granular cotton molded product (hereinafter, also simply referred to as “molded product”) according to the present embodiment is one in which granular cotton is integrated without being adhered to each other by entanglement of fibers, and is granular. Three-dimensional crimping is expressed in at least a part of the fibers constituting cotton. The three-dimensional crimping is not particularly limited as long as the granular cotton molded product according to the present invention can be obtained, but for example, a latent crimpable composite fiber that develops three-dimensional crimping by performing a specific post-treatment can be used. It may be a steric crimp developed by performing the specific post-treatment. Such latent crimpable composite fibers are, for example, fibers that exhibit three-dimensional crimping while heat-shrinking by heating, and resin components by absorbing moisture in the air or impregnating it in water to absorb moisture. There is no particular limitation as long as a granular cotton molded product according to the present invention can be obtained, which contains fibers or the like in which a part of the above swells and / or stretches and develops three-dimensional crimping.

Further, the granular cotton molded product of the present embodiment is, for example,
Prepare granular cotton containing latent crimpable composite fibers;
Fill a container (or mold) with a certain space so that the granular cotton is dense enough to come into contact with each other;
Performing a crimping expression treatment to develop three-dimensional crimping on the latent crimping composite fiber existing at the contact portion between the granular cottons between the granular cottons;
Three-dimensional crimping occurs in the latent crimpable composite fibers existing at the contact portion between the granular cottons existing between the granular cottons, and the fibers expressing the three-dimensional crimps are entangled with the adjacent granular cottons. By doing so, it is integrated without being glued;
It can be produced by integrating granular cottons with each other without adhering them, and may be produced by such a production method.

In the crimping expression treatment, for example, when granular cotton containing latent crimping composite fiber that develops three-dimensional crimping by heat is used, the thermal shrinkage of the latent crimping composite fiber starts, and the three-dimensional crimping occurs. Heating above the temperature at which manifestation and / or manifestation begins; and when using granular cotton containing latent crimpable composite fibers that develop steric crimps by absorbing moisture, in a hot and humid atmosphere or in a warm water tank Including holding at.
Hereinafter, first, the fibers constituting the granular cotton molded product will be described.

[Latent crimpable composite fiber]
As described above, the fibers constituting the granular cotton molded body are fibers in which three-dimensional crimping is expressed in the latent crimping composite fiber, that is, the latent crimping composite after three-dimensional crimping is developed and manifested. It may be a fiber (also referred to as a "crimpable composite fiber"). In the following, first, the latent crimpable composite fiber before the development of three-dimensional crimping will be described.

The latent crimpable composite fiber that may be used in the present embodiment is a fiber that develops three-dimensional crimp by performing a specific treatment (crimp expression treatment) such as heat treatment and / or treatment in a warm water bath. It can be used without particular limitation. That is, for example, a fiber produced by using at least two kinds of resins having different shrinkage rates or resin components by a specific treatment can be exemplified.

More specifically, as the latent crimpable composite fiber, for example, at least two types of thermoplastic resins having different heat shrinkage rates (for example, the first component and the second component) are used, and the melting point of these thermoplastic resins is used. Composite fibers that develop three-dimensional crimping by using the difference in heat shrinkage of these resins by heating and / or heat treatment at a lower temperature (also referred to as "thermoplastic latent crimpable composite fibers"). And at least two types of thermoplastic resins (for example, the first component and the second component), that is, a thermoplastic resin whose length changes between a moisture absorbing state and a dry state, and a thermoplastic resin that does not absorb moisture or does not change its length even if it absorbs moisture. A composite fiber (also referred to as “moisture-sensitive latent crimpable composite fiber”) that develops three-dimensional crimping by using the component) and utilizing the difference in the rate of change of the resin with respect to humidity can be exemplified.
In the granular cotton molded product of the present invention, the expression of three-dimensional crimp is easy, the expression of three-dimensional crimp is irreversible, and after the granular cotton is entangled and integrated, the entanglement is difficult to unravel. Therefore, it is preferable to use a heat-sensitive latent crimping composite fiber.

In the present invention, the heat-sensitive latent crimpable composite fiber contains, for example, a first component and a second component having a melting point Tf ₂ higher than the melting point Tf ₁ of the first component, and is three-dimensional when subjected to heat treatment. It is a fiber that expresses crimping. The first component exhibits higher heat shrinkage than the second component, and the difference in shrinkage between the two components can be used to develop three-dimensional crimping. The heat-sensitive latent crimpable composite fiber exists in a state in which three-dimensional crimping is exhibited by being subjected to heat treatment, that is, as a crimpable composite fiber in the molded product of the present embodiment. In the granular cotton molded product, the crimpable composite fibers exhibit three-dimensional crimps such as wavy crimps and / or spiral crimps (or coil crimps) described later. The thermal latent crimpable conjugate fiber in the present invention, according to JIS-L-1015, initial load 0.018mN / dtex (2mg / de) , the temperature _Tf 1 -5 (℃), was measured under conditions of 15 minutes dry heat shrinkage rate of 95% 10% or more or less, preferably 90% or less than 15% and fibers after treatment for 15 min at _Tf 1 -5 (℃) refers to a fiber that express a stereoscopic crimps ..

The melting point Tf ₁ of the first component and the melting point Tf ₂ of the second component can be obtained from the heat of fusion curve obtained by DSC. In the heat of fusion curve, two or more peaks may appear for one component. In that case, the temperature showing the maximum peak is defined as the melting peak temperature, that is, the melting point.

(1st component)
As the first component, for example, a propylene copolymer containing 50% by mass or more of propylene (hereinafter, simply referred to as "propylene copolymer"), a copolymer of ethylene and butene-1, hexene-1, and octene-1. Examples thereof include an ethylene-α-olefin copolymer such as a linear low-density polyethylene, a polyester-based copolymer, and the like. Since these copolymers exhibit high heat shrinkage, the heat-sensitive latent crimpable composite fiber containing this as a first component tends to exhibit three-dimensional crimping.

Alternatively, as long as the first component can form, for example, a heat-sensitive latent crimpable composite fiber having a difference in heat shrinkage and melting point from the second component and exhibiting three-dimensional crimp together with the second component. In, it may be another thermoplastic resin. Other thermoplastic resins include, for example, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate and copolymers thereof, polypropylene, polyethylene (high density polyethylene, Polyester-based resins such as (including low-density polyethylene, etc.), polybutene-1, ethylene-vinyl alcohol copolymer, and ethylene-vinyl acetate copolymer, and polyamide-based resins such as nylon 6, nylon 12, and nylon 66, etc. Is.
The first component may include two or more thermoplastic resins.

The first component may contain, in particular, a propylene copolymer or an ethylene-α-olefin copolymer in an amount of 50% by mass or more, preferably 80% by mass or more. Alternatively, the first component may be substantially composed of a propylene copolymer or an ethylene-α-olefin copolymer alone without containing other thermoplastic resins. Since these copolymers exhibit high heat shrinkage at a relatively low temperature, the use of these copolymers causes three-dimensional crimping at a relatively low temperature, and the molded product of the present embodiment can be produced. .. Hereinafter, these copolymers will be described.

The propylene copolymer is a copolymer obtained by copolymerizing propylene with an α-olefin other than propylene, and contains propylene as a main monomer component. In this embodiment, either a random copolymer or a propylene copolymer, which is a block copolymer, can be used. Considering heat shrinkage, a random copolymer is preferable.

In the propylene copolymer, the monomer copolymerizing with propylene is, for example, an α-olefin having 2 to 20 carbon atoms (excluding propylene having 3 carbon atoms) such as ethylene, butene-1, hexene-1, and octene-1. ) Is one or more monomers selected from. The propylene copolymer is preferably at least one selected from a propylene-ethylene copolymer and a propylene-1-butene-ethylene copolymer.

In the case of a propylene-ethylene copolymer, the ethylene content is preferably 1% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and even more preferably 1.2% by mass or more and 10% by mass. % Or less, particularly preferably 1.5% by mass or more and 6.5% by mass or less, and most preferably 1.5% by mass or more and 6.5% by mass or less. A propylene copolymer having an ethylene content within this range is likely to shrink by heat treatment at, for example, 100 ° C. to 140 ° C., and is likely to satisfactorily develop a desired three-dimensional crimp in a composite fiber.

In the case of the propylene-1-butene-ethylene copolymer, the 1-butene content is preferably 0.1% by mass or more and 3.5% by mass or less, and the ethylene content is preferably 1% by mass or more and 7% by mass or less. A propylene-1-butene-ethylene copolymer having a content of 1-butene and ethylene in the above range is also heat-treated at, for example, 100 ° C. to 140 ° C., similarly to the propylene-ethylene copolymer described above. It is easy to shrink at The 1-butene content may be more preferably 1% by mass or more and 3.2% by mass or less, particularly preferably 1.5% by mass or more and 3% by mass or less, and most preferably 1.8% by mass. It may be 2.8% by mass or less. The ethylene content may be more preferably 2% by mass or more and 4.5% by mass or less, particularly preferably 2.5% by mass or more and 4% by mass or less, and most preferably 2.8% by mass or more 3 It may be 0.8% by mass or less.

The melt flow rate (MFR; measurement temperature 230 ° C., load 21.18 N (2.16 kgf)) specified by JIS-K-7210 of the propylene copolymer is preferably 50 g / 10 minutes or less, and is preferably 15 g / 10 minutes. More preferably, it is in the range of 30 g / 10 minutes or less. When the melt flow rate is within this range, the spinnability at the time of fiber production is good.

The propylene copolymer preferably used can be specified as a propylene-ethylene random copolymer having a melting peak temperature of 145 ° C. or lower, more specifically 130 ° C. or higher and 145 ° C. or lower. When the melting peak temperature is less than 130 ° C., the polymer exhibits rubber-like elasticity, and the card-passability of the fiber is deteriorated. If the melting peak temperature exceeds 145 ° C., the heat shrinkage may decrease and the occurrence of steric crimp may be insufficient.

Further, an ethylene-α-olefin copolymer that can be used as the first component of the heat-sensitive latent crimpable composite fiber will be described. The ethylene-α-olefin copolymer is a copolymer obtained by copolymerizing ethylene and an α-olefin, and contains ethylene as a main monomer component. Ethylene-α-olefin copolymers are also called linear low density polyethylene. Alpha-olefins generally have 3-12 carbons. Examples of α-olefins having 3 to 12 carbons are propylene, butene-1, penten-1, 4-methylpentene-1, hexene-1, heptene-1, octene-1, nonene-1, and decene. 1. Dodecene-1 and mixtures thereof can be mentioned. Of these, propylene, butene-1, 4-methylpentene-1, hexene-1, 4-methylhexene-1 and octene-1 are particularly preferable, and butene-1 and hexene-1 are even more preferable. The α-olefin content may be, for example, 0.3 mol% to 50 mol%, 0.3 mol% to 40 mol%, 0.4 mol% to 10 mol%, or outside these ranges. There may be.

The ethylene-α-olefin copolymer may have a density of, for example, 0.850 g / cm ^{3 to} 0.940 g / cm ³ , preferably 0.880 g / cm ^{3 to} 0.935 g / cm ³ , and more. It preferably has a density of 0.905 g / cm ^{3 to} 0.935 g / cm ³ , and even more preferably 0.910 g / cm ^{3 to} 0.933 g / cm ³ . When the density is 0.850 g / cm ³ or more, the first component has an appropriate softness, and it is easy to obtain an appropriate bulkiness and bulk recovery property when the molded product is formed, which is preferable. On the other hand, when the density of the ethylene-α-olefin copolymer is 0.940 g / cm ³ or less, when a granular cotton molded product is formed, it has an appropriate surface feel and an appropriate flexibility in the thickness direction of the molded product. It is easy to obtain and is preferable.

The melting point of the ethylene-α-olefin copolymer is preferably less than 130 ° C. When the melting point of the ethylene-α-olefin copolymer is less than 130 ° C., the temperature of the heat treatment can be set to an appropriate level in order to develop steric crimping, and the tactile sensation of the molded product is preferable. The melting point of the ethylene-α-olefin copolymer may be, for example, 85 ° C. or higher and 128 ° C. or lower, 100 ° C. or higher and 125 ° C. or lower, or 105 ° C. or higher and 125 ° C. or lower. Good.

The ethylene-α-olefin copolymer may be polymerized using a metallocene catalyst. By using a metallocene catalyst, an ethylene-α-olefin copolymer having the above-mentioned density, melting point, MI and the like described later can be easily obtained. Alternatively, the ethylene-α-olefin copolymer is not limited to those polymerized using a metallocene catalyst, and may be obtained by, for example, polymerizing using a Ziegler-Natta catalyst.

Considering the spinnability, the ethylene-α-olefin copolymer is preferably 1 g / 10 min to 60 g / 10 min, more preferably 2 g / 10 min to 40 g / 10 min, and even more preferably 3 g / 10 min to. It has a melt index (MI) in the range of 35 g / 10 min, most preferably 5 g / 10 min to 30 g / 10 min. MI is measured according to JIS K 7210 (1999) (condition: 190 ° C., load 21.18 N (2.16 kgf)). The larger the MI, the slower the solidification rate of the first component, which leads to the fusion of fibers. On the other hand, if the MI is too small, fiber production becomes difficult.

The ratio (Q value: Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) in the ethylene-α-olefin copolymer is preferably 5 or less. The Q value is more preferably 2 to 4, and even more preferably 2.5 to 3.5. A Q value of 5 or less means that the width of the molecular weight distribution of the ethylene-α-olefin copolymer is narrow. By using an ethylene-α-olefin copolymer having a Q value within the above range as the first component, steric crimping is more favorably developed by heat treatment. The Q value is calculated by obtaining a molecular weight distribution curve using, for example, a high-temperature GPC apparatus, and obtaining the number average molecular weight Mn and the weight average molecular weight Mw from the molecular weight distribution curve.

When the first component contains an ethylene-α-olefin copolymer, the heat-sensitive latent crimpable composite fiber itself becomes flexible, and the tactile sensation of the molded product can be softened. Further, since the ethylene-α-olefin copolymer can be thermally shrunk at a lower temperature than the propylene copolymer, the first component is a heat-sensitive latent crimp containing the ethylene-α-olefin copolymer. The polymer composite fiber can exhibit steric crimping at, for example, less than 100 ° C., in some cases 95 ° C. or lower, and in some cases 90 ° C. or lower, and the polymer of the present embodiment can exhibit at a relatively low heat treatment temperature. Makes it possible to manufacture.

The above-mentioned densities, Q values, and MIs described in relation to the resins (copolymers) that can constitute the first component are all those before spinning, but the densities, melting points, and melting points of each resin after spinning. The Q value and MI are also preferably within the above ranges. The density of the resin after spinning is measured for the resin contained in the first component of the composite fiber. When it is difficult to measure the density of the resin constituting the composite fiber, only the resin is spun under the same conditions as the spinning conditions of the composite fiber (spinning temperature is the first component). The density or the like of the obtained single fiber may be measured, and the measured value may be used as the density or the like after spinning of the resin.

(Second component)
The second component has, for example, a melting point Tf ₂ higher than the melting point Tf ₁ of the first component. Tf ₂ may be higher than Tf ₁ by 10 ° C. or higher, and in particular, Tf ₂ may be higher than Tf ₁ by 15 ° C. or higher. If the difference between Tf ₁ and Tf ₂ is small, good crimp expression may not be obtained.

Examples of the resin that can be used as the second component include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and copolymers thereof, and polyamide resins such as nylon 6, nylon 66, and copolymers thereof. In addition, polyolefin resins such as polypropylene and polymethylpentene can be mentioned. The second component may contain two or more resins selected from these. The degree of shrinkage of the second component, if any, is smaller than that of the first component, and imparts rigidity to the heat-sensitive latent crimpable composite fiber.

The second component may contain polypropylene having a melting point of 150 ° C. or higher in an amount of 50% by mass or more, preferably 80% by mass or more. Alternatively, the second component does not contain other thermoplastic resins and may consist substantially of polypropylene alone. Polypropylene is preferably used as the second component from the viewpoints of spinnability, fiber crimping property, shrinkage property of the resin itself, and the like. Further, since polypropylene is a resin that is more flexible than polyester resins such as polyethylene terephthalate, it is more flexible than heat-sensitive latent crimpable composite fibers containing polyethylene terephthalate as the second component, which will be described later. It is believed to provide latent crimping composite fibers.

Alternatively, the second component may contain polyethylene terephthalate in an amount of 50% by mass or more, preferably 80% by mass or more. In addition, the second component does not contain other thermoplastic resins and may be substantially composed of polyethylene terephthalate alone. Polyethylene terephthalate has excellent spinnability, and fibers containing this as a second component have excellent crimping properties. Further, since polyethylene terephthalate is a resin having a higher melting point and higher elasticity than the polypropylene resin described above, a molded product containing fibers contained in the second component can be heat-treated at a relatively high temperature. The bulk is hard to decrease. Furthermore, since fibers containing polyethylene terephthalate as a constituent tend to increase the elasticity of the fibers themselves, heat-sensitive latent crimpable composite fibers containing polyethylene terephthalate as the second component are used in applications where a bulky molded body is required. Is suitable.

(Combination of 1st component and 2nd component)
The heat-sensitive latent crimpable composite fiber containing a preferable combination of the first component and the second component is
1) Heat-sensitive latent crimp composite fiber containing a combination of a first component containing an ethylene-α-olefin copolymer and a second component containing polypropylene; and 2) a first component containing a propylene copolymer. It is a combination with a second component containing polypropylene, and one or both components include a heat-sensitive latent crimpable composite fiber containing a polyolefin-based elastomer.

<About the combination of 1) above>
In the combination of 1) above, the first component is substantially composed of an ethylene-α-olefin copolymer, or contains 60% by mass or more of the ethylene-α-olefin copolymer, and 0.880 g / cm ³ or more as a whole. It preferably has a density of 0.935 g / cm ³ or less. The ratio (Q value) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of polypropylene contained in the second component is not particularly limited, but is preferably 2 to 8, and the Q value is larger than 4. Is preferable. The heat-sensitive latent crimp-sensitive composite fiber containing such a combination of the first component and the second component does not have too large a crimp-developing ability and appropriately develops three-dimensional crimp. Therefore, the molded product of the present embodiment. Suitable for.

In the combination of 1) above, it is preferable that the first component is substantially composed of only an ethylene-α-olefin copolymer. Here, the term "substantially" is used in consideration of the fact that the proportion of the ethylene-α-olefin copolymer is not completely 100% by mass when additives such as stabilizers are included. I'm using it. The ratio of the additive or the like is, for example, 5% by mass or less, preferably 3% by mass or less, and most preferably 1% by mass or less.

Alternatively, the first component comprises ethylene -α- olefin copolymer of at least 60 wt%, and the density of the entire first component 0.915 g / cm ³ or more, preferably 0.920 g / cm ³ or more, more preferably Is 0.925 g / cm ³ or more. When the proportion of the ethylene-α-olefin copolymer is 60% by mass or more, the heat shrinkage of the first component can be more appropriate, or the crimp-developing ability of the fiber can be more appropriate. Further, when the total density of the first component composed of the ethylene-α-olefin copolymer and other components is 0.915 g / cm ³ or more, the crimp-developing ability of the obtained fiber is appropriate. , More preferred. When the first component contains a component (resin) other than the ethylene-α-olefin copolymer, the first component preferably contains at least 70% by mass of the ethylene-α-olefin copolymer, and preferably at least 75% by mass. It is more preferable to include it.

When the first component is a thermoplastic resin component containing at least 60% by mass of the ethylene-α-olefin copolymer, the thermoplastic resin other than the ethylene-α-olefin copolymer contained in the first component is not particularly limited. However, it is preferable that the resin has some compatibility with the ethylene-α-olefin copolymer resin. Since the thermoplastic resin other than the ethylene-α-olefin copolymer contained in the first component has compatibility with the ethylene-α-olefin copolymer, thread breakage is less likely to occur during melt spinning, and production efficiency is reduced. Is considered to be high. The thermoplastic resin other than the ethylene-α-olefin copolymer contained in the first component is preferably a polyolefin-based thermoplastic resin such as polypropylene, high-density polyethylene, or low-density polyethylene, but a polyolefin-based elastomer is preferable. .. In the combination of 1) above, the first component contains 60% by mass or more of the ethylene-α-olefin copolymer, and in addition, the polyolefin-based elastomer suppresses the occurrence of excessive steric crimping in the composite fiber. In addition, the entire fiber has appropriate elasticity, and it is possible to suppress a decrease in bulk (sagging) over time when the molded product is formed.

The polyolefin-based elastomer is preferably contained in an amount of 5% by mass or more and 40% by mass or less of the first component, more preferably 10% by mass or more and 30% by mass or less, and particularly preferably 12% by mass or more. It is contained in an amount of 25% by mass or less. If the proportion of the polyolefin-based elastomer is less than 5% by mass, it becomes difficult to obtain the effect of containing the elastomer, and if it exceeds 40% by mass, the spinnability at the time of fiber production may decrease.

As the polyolefin-based elastomer, one or more polyolefin resins selected from polyethylene, polypropylene, and a copolymer of propylene and an α-olefin having 4 or more carbon atoms, for example, 4 or more and 8 or less carbon atoms are used as hard segments. Examples thereof include thermoplastic elastomers having α-olefin rubber or other rubber as a soft segment. The α-olefin rubber may be, for example, a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. Examples of α-olefins include propylene, 1-butene, 1-pentene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-decene, 1 -Dodecene, 1-tetradecene, 1-octadecene and the like can be mentioned. More specifically, the α-olefin rubber may be, for example, ethylene propylene rubber such as ethylene-propylene rubber, ethylene-butene rubber, and ethylene propylene-diene rubber. Other rubbers that serve as soft segments include, for example, isoprene rubber, butadiene rubber, butyl rubber, propylene-butadiene rubber, acrylonitrile-butadiene rubber, and diene rubbers such as acrylonitrile-isoprene rubber.

In the combination of 1) above, the second component preferably contains polypropylene having a Q value of 2 or more and 8 or less. When the second component contains such polypropylene, the crimp-developing ability of the composite fiber becomes appropriate, and when heat-treated as the crimp-developing treatment, gentle three-dimensional crimp is preferably expressed in the fiber. It becomes. The Q value of polypropylene is more preferably 4 or more and 6.5 or less, most preferably 4 or more and 6 or less, and further preferably 4.5 or more and 6 or less. The larger the Q value, the lower the crimp-developing ability of the fiber, but if the Q value is too large, the crimp-developing ability may become too low. The range described here is for the Q value after spinning, but it is preferable that the Q value before spinning is also within the range described here.

The Q value after spinning is measured for polypropylene contained in the second component in a fibrous state. When it is difficult to measure the Q value of polypropylene contained in the second component constituting the composite fiber, only polypropylene is used under the same conditions as the spinning conditions of the composite fiber (spinning temperature is that of the second component). ), The Q value of the single fiber obtained by spinning may be measured, and the measured value may be used as the Q value of polypropylene contained in the second component of the present embodiment.

The second component is substantially composed only of polypropylene having a Q value of 2 or more and 8 or less, more preferably 4 or more and 6.5 or less. Here, the term "substantially" is used in the sense described in relation to the first component.
When the second component contains a component other than polypropylene having a Q value of 2 or more and 8 or less, more preferably 4 or more and 6.5 or less, the second component preferably contains at least 75% by mass of the polypropylene. If the proportion of polypropylene is less than 75% by mass, it may not be possible to obtain a heat-sensitive latent crimpable composite fiber having a crimp-developing ability necessary for obtaining the granular cotton molded product of the present invention.

<About the combination of 2) above>
In the combination of 2) above, the first component contains a propylene copolymer, and the second component has a Q value (ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw / Mn)) of 3. The proportion of the polyolefin-based elastomer in the component containing polypropylene which is 5 or more and 6.5 or less, and one or both of the first component and the second component contains a polyolefin-based elastomer and contains a polyolefin-based elastomer. Is preferably 10% by mass or more and 30% by mass or less.

In the combination of 2) above, the second component contains polypropylene having a Q value of 3.5 or more and 6.5 or less. By using polypropylene having a Q value within this range, it is possible to obtain a composite fiber in which three-dimensional crimping is unlikely to occur excessively. When the Q value is less than 3.5, the degree of steric crimp becomes strong, and when the Q value exceeds 6.5, steric crimp is less likely to occur. The Q value described here is also the Q value after spinning, and the meaning of the Q value after spinning and the measuring method thereof are as described in relation to the combination of 1) above.

In the combination of 2) above, either one or both of the first component and the second component contains a polyolefin-based elastomer. By containing the polyolefin-based elastomer, the expression of excessive three-dimensional crimping in the composite fiber can be suppressed, and the entire fiber has appropriate elasticity, and the bulk of the molded product is reduced (sagging) with time. Can be suppressed.

The polyolefin-based elastomer is preferably contained in an amount of 10% by mass or more and 30% by mass or less, and more preferably 12% by mass or more and 25% by mass or less of the component containing the polyolefin-based elastomer. If the proportion of the polyolefin-based elastomer is less than 10% by mass, it becomes difficult to obtain the effect of containing the elastomer, and if it exceeds 30% by mass, the spinnability during fiber production may decrease. When the polyolefin-based elastomer is contained in both the first and second components, the ratio of the polyolefin-based elastomer to the total mass of the fiber is preferably 10% by mass or more and 30% by mass or less.

The polyolefin-based elastomer may be contained only in the first component. As described above, since the first component contains a propylene copolymer which is a heat-shrinkable component, if the second component contains a polyolefin-based elastomer, the heat-shrinkability of the first component can be easily controlled, and a desired three-dimensional object can be obtained. It is easy to design the composite fiber to have crimp.

As the polyolefin-based elastomer, one or more polyolefin resins selected from polyethylene, polypropylene, and a copolymer of propylene and an α-olefin having 4 or more carbon atoms, for example, 4 or more and 8 or less carbon atoms are used as hard segments. Examples thereof include thermoplastic elastomers having α-olefin rubber or other rubber as a soft segment. The α-olefin rubber may be, for example, a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. Examples of α-olefins include propylene, 1-butene, 1-pentene, 3,3-dimethyl-1-butene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-decene, 1 -Dodecene, 1-tetradecene, 1-octadecene and the like can be mentioned. More specifically, the α-olefin rubber may be, for example, ethylene propylene rubber such as ethylene-propylene rubber, ethylene-butene rubber, and ethylene propylene-diene rubber. Other rubbers that serve as soft segments include, for example, isoprene rubber, butadiene rubber, butyl rubber, propylene-butadiene rubber, acrylonitrile-butadiene rubber, and diene rubbers such as acrylonitrile-isoprene rubber.

(Cross-sectional structure and other configurations of latent crimpable composite fibers)
The latent crimpable composite fiber preferably has a cross-sectional structure in which the first component is exposed at a length of 20% or more with respect to the length of the peripheral surface of the fiber. As such a cross-sectional structure, an eccentric core sheath type cross section in which the first component is a sheath component, the second component is a core component, and the position of the center of gravity of the second component (core component) is deviated from the position of the center of gravity of the fiber, and An example is a parallel cross section in which the first component and the second component are bonded together. According to such a cross-sectional structure, it is possible to obtain a composite fiber having excellent shrinkage property and excellent crimping property. Fibers having an eccentric core sheath type cross section are referred to as eccentric core sheath type composite fibers, and fibers having a parallel type cross section are also referred to as parallel type composite fibers (or side-by-side type composite fibers).
When the latent crimpable composite fiber is an eccentric core sheath type composite fiber, the eccentricity of the second component is preferably in the range of 15 to 60%, and preferably in the range of 20 to 50%. More preferably, it is particularly preferably in the range of 30 to 50%. The eccentricity referred to here is defined by the following equation.

The composite ratio of the first component and the second component may be in the range of 15:85 to 85:15 in volume ratio, preferably 25:75 to 75:25, and more preferably 35:65 to 65: It is 35, and particularly preferably 4: 6 to 6: 4. If the ratio of the first component is too small, the ratio of the component that shrinks due to heat or moisture absorption to the composite fiber becomes small, so that the expression of three-dimensional crimping may be insufficient, and the ratio of the first component is too large. As a result, it becomes too easy to develop three-dimensional crimps, which makes it difficult to adjust the conditions of the process for developing three-dimensional crimps, which may affect productivity and the second component becomes too small, resulting in fiber stiffness. , The elasticity may be lost, and the bulkiness and bulk recovery of the obtained granular cotton molded product may decrease.

When the latent crimpable composite fiber is a heat-sensitive latent crimpable composite fiber and the combination of the first component and the second component is 1) above, the composite ratio of the first component and the second component is 45 by volume. It is preferably in the range of: 55 to 15:85, and preferably in the range of 43:57 to 30:70. In the combination of 1) above, if the ratio of the first component is too large, that is, if it exceeds 45, the heat shrinkage of the fiber may become too large and crimping may be excessively expressed, or the ratio of the second component may be too large. If it becomes too small, the elasticity and elasticity of the fiber may be lost, and a granular cotton molded product having sufficient initial bulk and bulk recovery may not be obtained. In the combination of 1) above, if the ratio of the first component is too small, that is, if the ratio of the first component is less than 15, the shrinkage of the entire fiber may be insufficient and three-dimensional crimping may not occur.

The fineness of the latent crimpable composite fiber is not particularly limited. For example, the latent crimpable composite fiber may have a fineness of 0.5 dtex to 30 dtex, preferably 0.8 dtex to 20 dtex, and more preferably 1.1 dtex to 18 dtex. When the molded product is made of composite fibers having a fineness within the above range, it is easy to obtain a batting having excellent bulkiness and less decrease in bulk over time.

The fiber length of the latent crimpable composite fiber is also not particularly limited. To form granular cotton, the fiber length may be, for example, in the range of 1 mm to 100 mm, in the range of 15 mm to 72 mm, in the range of 20 mm to 64 mm, or in the range of 20 mm to 64 mm. It may be in the range of 24 mm to 48 mm, or may be in the range of 28 mm to 42 mm.

The latent crimpable composite fiber develops three-dimensional crimping when subjected to a moisture absorption treatment such as heat treatment and holding in a hot water tank. Here, the term "three-dimensional crimp" is used to distinguish it from mechanical crimp in which the crest (or peak) of the crimp as shown in FIG. 3 has an acute angle. Further, "three-dimensional crimping is expressed" means, for example, a crimp in which a mountain portion is curved as shown in FIG. 1A (also referred to as "wave-shaped crimping"), or a peak portion as shown in FIG. 1B. Spirally curved crimps (also referred to as "spiral crimps" or "coiled crimps"), crimps in which wavy and spiral crimps are mixed, as shown in FIG. 1C, and FIG. It means that the crimping in which at least one of the mechanical crimping, the wavy crimping and the spiral crimping is mixed as shown in 2 is expressed.

The latent crimpable composite fiber is a roll for facilitating the production of granular cotton before it is subjected to a treatment for manifesting latent three-dimensional crimps such as heat treatment and moisture absorption treatment to develop three-dimensional crimps. May have shrinkage. The crimp may be mechanical crimp, or a part of three-dimensional crimp may be expressed and mixed with mechanical crimp. The number of crimps may be, for example, 8 pieces / 25 mm or more and 30 pieces / 25 mm or less, particularly 10 pieces / 25 mm or more and 28 pieces / 25 mm or less, and more particularly 12 pieces / 25 mm or more and 24 pieces / 25 mm. It may be:

[Granular cotton]
The granular cotton constituting the molded product of the present embodiment contains latent crimpable composite fibers. The latent crimpable composite fiber is contained in the granular cotton, preferably 30% by mass or more, more preferably 50% by mass or more, further preferably 70% by mass or more, and most preferably 80% by mass or more of the latent crimpable composite fiber. included. If the content of the latent crimpable composite fiber is less than 30% by mass, the granular cotton may not be well integrated and a molded product may not be obtained.

If the granular cotton contains fibers other than latent crimpable composite fibers, the other fibers include, for example, natural fibers such as cotton, silk, wool, linen, and pulp, rayon, cupra, and solvent-spun cellulose fibers. Regenerated fibers such as acrylic, polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, and polyesters such as polybutylene succinate and its copolymers, nylon 6, nylon 12, and nylon. Amid-based such as 66, polypropylene, polyethylene (including high-density polyethylene, low-density polyethylene, etc.), polybutene-1, ethylene-vinyl alcohol copolymer, and polyolefin-based such as ethylene-vinyl acetate copolymer, and polyurethane-based. Synthetic fibers such as. When the other fiber is a synthetic fiber, the synthetic fiber does not have latent crimpability. The synthetic fiber may be a single fiber or a composite fiber composed of two or more resins selected from the above resins. For example, the composite fiber may be a core-sheath type composite fiber or a split type composite fiber. As other fibers, two or more fibers may be used in combination.

The granular cotton used in the present embodiment can be produced by a known method for producing granular cotton. Specifically, a latent crimpable composite fiber cut to a specific length and, if necessary, other fibers are prepared. Next, if necessary, latent crimpable composite fibers and, if used, other fibers are opened. Then, these fibers are weighed in a predetermined amount, and the fibers are entangled with each other using a known grain cotton manufacturing apparatus to obtain granular cotton.

As the granular cotton manufacturing apparatus, a high-speed airflow is used, and the raw material fibers are entangled and granulated under the high-speed airflow (for example, described in Patent Document 4), and the fibers are scraped into a rotatable metal container. There is a manufacturing apparatus (for example, described in Patent Document 5) in which blades are provided, fibers are put into the container, and then the metal container is rotated to obtain granular cotton. Further, there is also a manufacturing method (for example, described in Patent Document 6) in which fibers as a raw material are agglomerated, sandwiched between a cylindrical inner surface and a spiral groove, and made spherical by rotating the spiral groove. The apparatus and method for producing granular cotton are not particularly limited as long as they are an apparatus and a method for producing granules by entwining fibers, and any apparatus and method may be used.

The diameter of the granular cotton is not particularly limited, and may be, for example, 2 mm or more and 30 mm or less. The diameter of the granular cotton can be adjusted to an arbitrary value in each manufacturing method, and in the manufacturing method of stirring the fibers under the high-speed airflow to obtain granular cotton, the time for stirring the fibers under the high-speed airflow can be adjusted. , Can be made larger and can be made smaller.

In the granular cotton used in the present embodiment, the fibers are not substantially adhered to each other. That is, the constituent fibers are not adhered to each other at the stage of processing the raw material fibers into granular cotton or after processing into granular cotton. In various granular cottons, as a method of adhering between the constituent fibers, a method of heat-treating the granular cotton to melt a part of the constituent fibers to heat-bond the constituent fibers, and a stage of producing the granular cotton and granules. A method is known in which various adhesives are added to bond the constituent fibers to each other, but the granular cotton used in the present embodiment is not intentionally subjected to these treatments, and the granular cotton is substantially used. The shape is maintained only by the entanglement of fibers. In granular cotton, if the constituent fibers are bonded together, the bulk of the granular cotton tends to decrease, and the shape of the granular cotton is fixed in a certain shape. Therefore, fill a space with a complicated shape as a batting material. In this case, it is easy to form a space that is not filled with the batting material without reaching the details of the space. In addition, the texture of the granular cotton molded product obtained by firmly adhering the granular cotton to each other by melting a part of the constituent fibers and adhering them with an adhesive is likely to become hard, and the texture is felt. There is a risk of damage.

In the granular cotton used in the present embodiment, the latent crimpable composite fiber has the ability to develop latent crimp even if three-dimensional crimp is not expressed or three-dimensional crimp is developed. ing. As will be described later, the molded product of the present embodiment utilizes the fact that entanglement occurs between the fibers constituting the granular cotton when the three-dimensional crimp occurs in the latent crimpable composite fiber, thereby achieving the integrity between the granular cotton. Secure. Therefore, when the latent crimpable composite fiber expresses three-dimensional crimping and does not develop three-dimensional crimping any more, it becomes difficult to bond the granular cottons to each other.

[Granular cotton molded product]
The granular cotton molded product of the present embodiment is a molded product in which the granular cotton is integrated without being adhered to each other by entanglement of the fibers constituting the granular cotton, and at least a part of the fibers constituting the granular cotton. Three-dimensional crimps are expressed in. That is, the granular cotton molded product of the present embodiment contains crimpable composite fibers having at least a part of three-dimensional crimps, and the crimpable composite fibers or the crimpable composite fibers and other fibers (other fibers). It is a molded product that is entangled with (only when it contains), thereby ensuring integrity. Here, "the granular cotton is integrated" means that the force at the time of breaking the sample (hereinafter referred to as "breaking strength") measured by the following method is 0.03N or more. That is, clips having a grip width of 63 mm (large eyeball clips manufactured by KOKUYO Co., Ltd.) are attached to both ends of the granular cotton molded product, and one of the clips is fixed to the stand to allow the granular cotton molded product to hang down. Attach the plate on which the weight is placed to the other clip. The granular cotton molded product is hung down together with the dish, and the weight is gradually placed on the dish. When the elongation of the granular cotton molded product becomes large to some extent, the weight to be added is 1 g each, and when the weight is added, the elongation of the granular cotton does not stop, and the weight of the weight and the weight of the dish when the granular cotton molded product breaks. The force (N) when the granular cotton molded product is broken is measured from the sum of the above. When the breaking strength measured by this method is 0.03 N or more, it can be said that the granular cotton molded product is "integrated with each other". When measuring by the above method, the clip is attached to both ends of the longest side of the granular cotton molded product. If the breaking strength is less than 0.03N, there is no integrity as a molded body, and a part of granular cotton is easily detached from the molded body, making it difficult to handle as a single molded body.

In the granular cotton molded product of the present embodiment, the three-dimensional crimping is, for example, 20 pieces / 25 mm or more and 500 pieces / 25 mm or less, particularly 50 pieces / 25 mm or more and 400 pieces / 25 mm or less, and more particularly 70 pieces / 25 mm or more and 350 pieces. It may be expressed with a crimp number of / 25 mm or less. When three-dimensional crimping and mechanical crimping are mixed in the crimpable composite fiber, the three-dimensional crimping and the mechanical crimping are counted together, and the total number thereof is taken as the number of crimping of the three-dimensional crimping. If the number of three-dimensional crimps is small, the entanglement of the fibers between the cotton grains tends to be insufficient, and the granular cotton molded body may not be able to maintain its integrity. If the number of three-dimensional crimps is too large, the tactile sensation of the molded body is deteriorated, and the entire molded body tends to be hard, the cushioning property is lowered, and the bulk recovery rate may be reduced. In the granular cotton molded body, the number of crimps of the fibers expressing three-dimensional crimping is increased to about 20 to 100 times by using a scanning electron microscope or a stereomicroscope on a part of the granular cotton molded body. It is observed, photographed, and measured by counting the number of crimps from the image.

Moldings, for example, may have a density of 0.015 g / cm ³ or more 0.080 g / cm ³ or less, further, has a density of 0.025 g / cm ³ or more 0.080 g / cm ³ or less well, especially 0.030 g / cm ³ or more 0.070 g / cm ³ or less of the density, and more particularly may have a density of 0.035 g / cm ³ or more 0.065 g / cm ³ or less. A molded product having a too low density may have insufficient integrity as a molded product, and a molded product having an excessively high density may have excessive three-dimensional crimping, low cushioning property, and bulk recovery. May be smaller.

The molded product of the present embodiment may have, for example, a bulk recovery rate of 3% or more and 90% or less, particularly 5% or more and 80% or less, and more particularly 7% or more and 70% or less. You may have. The method for measuring the bulk recovery rate is as described in the column of Examples. A molded product having a bulk recovery rate in the above range has the property of being appropriately deformed when pressure is applied and easily returning to its original shape when pressure is removed. Therefore, it is a cushioning material used for furniture and the like. In addition, it can be suitably used as a batting material for clothing, a batting material for bedding products, and the like.

The molded product of the present embodiment can be produced, for example, by the method described below.
First, granular cotton containing latent crimpable composite fibers is prepared, and the granular cotton is placed in a container (or mold). The container shall have a shape and volume such that a molded product having a desired shape and size can be obtained. The container may be a breathable container made of, for example, a metal mesh or the like. When the latent crimpable composite fiber is a heat-sensitive latent crimpable composite fiber, the container is formed of a normal metal plate or a glass plate and does not have to be breathable, but sufficient hot air is sufficiently provided inside the granular cotton. It is preferable to use a breathable container from the viewpoint of allowing the fiber to penetrate the fiber and sufficiently develop the three-dimensional crimp. Into the container, the packing density of the granular cotton, for example, 0.004 g / cm ³ or more 0.05 g / cm ³ or less, particularly 0.006 g / cm ³ or more 0.035 g / cm ³ or less, more especially 0. 009g / cm ³ or more 0.025 g / cm ³ to become less, it may put the particulate cotton. If the packing density is too low, the integration of granular cotton may not proceed sufficiently. If the packing density is too high, the density of the obtained molded product may be too high. The problems when the density of the molded product is too high are as described above.

If necessary, a load may be applied to the aggregate of granular cotton in the container. For example, if a container having an open top surface is filled with granular cotton so as to overflow from the container and a member having an area approximately equal to the upper surface (for example, the lid of the container) is placed on the granular cotton, a load is applied by the member. The granular cotton can be compressed in the container to adjust the packing density.

The container containing the granular cotton is subjected to a treatment for manifesting the latent three-dimensional crimp according to the properties of the latent crimpable composite fiber to be used, and the latent crimpable composite fiber is subjected to the three-dimensional crimping. Alternatively, if three-dimensional crimps have already been developed in the latent crimpable composite fibers, the degree of three-dimensional crimps is increased to cause entanglement between the fibers constituting the granular cotton. If the latent crimpable composite fiber used is a heat-sensitive latent crimpable composite fiber, three-dimensional crimping is developed and / or manifested by heat treatment. The heat treatment may be, for example, a hot air processing process in which hot air is applied to the container. The hot air processing may be performed using, for example, a hot air penetration type heat treatment machine or a hot air blowing type heat treatment machine. Alternatively, heat treatment using infrared rays may be performed instead of the hot air processing.

The heat treatment temperature is appropriately selected according to the type of the component constituting the heat-sensitive latent crimpable composite fiber, particularly the resin constituting the first component. For example, if the melting point of the first component is Tf ₁ is heat treatment _temperature, Tf 1 -50 may be less than (℃) or Tf ₁ (℃), in _particular, Tf 1 -40 (℃) or Tf ₁ - 3 (℃) (℃) may be less than _Tf 1 -30 (℃) or _{Tf 1 -5 (℃) (℃} ) may be less than or equal to.
The heat treatment time may be, for example, 3 minutes to 30 minutes, particularly 5 minutes to 25 minutes, and more particularly 8 minutes to 20 minutes. If the heat treatment temperature is too low or the heat treatment time is too short, the latent crimpable composite fibers do not sufficiently develop three-dimensional crimping, and the fibers are not sufficiently entangled with each other, so that a molded product cannot be obtained. There is. If the heat treatment temperature is too high or the heat treatment time is too long, three-dimensional crimping may be excessively expressed in the latent crimpable composite fiber, and the density of the molded product may become too high.

More specifically, for example, when a heat-sensitive latent crimpable composite fiber in which the combination of the first component and the second component is the combination of the above 1) is used, the heat treatment temperature is, for example, 60 ° C to 110 ° C, particularly. , 80 ° C. to 105 ° C., and the heat treatment time may be, for example, 3 minutes to 60 minutes, particularly 5 minutes to 15 minutes.
When a heat-sensitive latent crimpable composite fiber in which the combination of the first component and the second component is the combination of the above 2) is used, the heat treatment temperature is, for example, 100 ° C. to 135 ° C., preferably 105 ° C. to 125 ° C. The temperature is preferably 120 to 135 ° C., and the heat treatment time may be, for example, 3 minutes to 30 minutes, preferably 5 minutes to 20 minutes, and particularly 5 minutes to 15 minutes.

If the latent crimpable composite fiber used is a moisture-sensitive latent crimpable composite fiber, three-dimensional crimping is performed by a moisture-absorbing treatment in which a part of the thermoplastic resin constituting the moisture-sensitive latent crimpable composite fiber absorbs moisture. And / or manifest. The moisture absorption treatment may be, for example, a treatment of impregnating a hot water tank adjusted to a constant temperature (for example, 80 to 100 ° C.), or a steam treatment of holding the heated steam in an atmosphere filled with steam.

By the process of revealing the latent three-dimensional crimp, the latent crimp composite fiber develops three-dimensional crimp, and when the fibers are entangled with each other, the aggregate of granular cotton in the container is integrated with the granular cotton. It becomes a molded product. At this time, the aggregate may shrink. For example, when filled with aggregate containers at a density of 0.004 g / cm ³ or more 0.05 g / cm ³ or less in the container, the resulting molded article, varies by the heat treatment temperature, 15% of the container volume It can have a volume of about ~ 85%.

In the molded product of the present embodiment, it is preferable that the fibers constituting the granular cotton are not adhered by the components constituting the fibers or by an adhesive. When the fibers are adhered to each other, the molded product becomes hard, the tactile sensation is deteriorated, the cushioning property is lowered, and the bulk recovery property is lowered. The molded product of the present embodiment has a soft and good tactile sensation and cushioning property because the integralness is ensured by the entanglement of the fibers in which the three-dimensional crimping is exhibited even if the fibers are not adhered to each other. Excellent and good bulk recovery.

[Use of molded product]
Since the molded product of the present embodiment is made of granular cotton integrated without being adhered to each other, it can be molded into a desired shape and size.
The molded body of the present embodiment includes a batting material used for clothing such as a down jacket, a batting material used for bedding such as a comforter, a shruff, and a pillow, and a cushioning material (for example, for automobiles, aircraft, and railroad vehicles). , Cushioning materials used for marine seats, as well as cushioning materials used for general household and office seats), clothing pads (for example, women's brassiere pads, shoulder pads, elbow pads, knee pads) Etc.), in addition to cushioning materials, can be used as sound absorbing materials, sound insulating materials, vibration isolating materials, vibration damping materials, heat insulating materials, heat insulating materials, etc., and can be used in technical fields where such materials are used. it can.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but these examples are for explaining the present invention and do not limit the present invention in any way.

The [fibers] used to produce the granular cotton molded articles of Examples and Comparative Examples are shown below.
Fiber 1: An eccentric core sheath type composite fiber in which the first component constitutes a sheath component and the second component constitutes a core component. The first component is a propylene-ethylene copolymer (trade name: Y2045GP manufactured by Prime Polymer Co., Ltd., melting point 140 ° C., MI 30 g / 10 minutes, ethylene content 4.78% by mass), and the second component is the second component. Assuming that the total mass of the components is 100% by mass, the polypropylene resin (manufactured by Prime Polymer Co., Ltd., a propylene homopolymer, trade name S105HG, melting point 160 ° C., MFR 30g / 10 minutes, Q value 4.7) is 85% by mass, propylene-based. It is a resin component containing 15% by mass of an elastomer (manufactured by Nippon Polypro Co., Ltd., trade name WELNEX (registered trademark), melting point 150 ° C., MI 30 g / 10 minutes, polypropylene elastomer in which a rubber component is nano-dispersed). Melt spinning using an eccentric core sheath type composite nozzle adjusted so that the composite ratio of the first component and the second component (first component / second component volume ratio) is 50/50 and the eccentricity is 50%. Was carried out to produce fiber 1. The fineness of the fiber 1 is 6.7 dtex, the fiber length is 38 mm, and the number of crimps is 16/25 mm. Fiber 1 has a dry heat shrinkage of 40% measured at a temperature of 120 ° C. under a load of 0.018 mN / dtex, and develops spiral and wavy three-dimensional crimps by heat treatment. It is a heat-sensitive latent crimpable composite fiber.

Fiber 2: An eccentric core sheath type composite fiber in which the first component constitutes a sheath component and the second component constitutes a core component. The first component is a resin component containing 85% by mass of linear low-density polyethylene and 15% by mass of low-density polyethylene when the total mass of the first component is 100% by mass, and the second component is polyethylene. It is terephthalate, and the composite ratio of the first component and the second component (first component / second component volume ratio) is 55/45, and the eccentric core sheath type composite nozzle adjusted so that the eccentricity is 25%. The fiber 2 was produced by performing melt spinning using the above. The fineness of the fiber 2 is 3.3 dtex, the fiber length is 38 mm, and the number of crimps is 13/25 mm. Fiber 2 is a manifest crimpable composite fiber in which wavy crimps and serrated crimps are mixed and expressed at the stage of the obtained fibers, and the temperature is 100 ° C. under the condition of load: 0.018 mN. It is a fiber that does not shrink heat even when heated with, and the development of three-dimensional crimping does not substantially proceed.

Fiber 3: Parallel composite fiber in which polyester resins with different melt viscosities are composited in parallel (manufactured by Unitika Ltd., trade name: H38F, fineness 6.7dtex, fiber length 51 mm, number of crimps: 10/25 mm) Is. Fiber 3 is a manifest crimpable composite fiber in which wavy crimps and serrated crimps are mixed and expressed at the stage of the obtained fibers, and does not heat shrink even when heated, and three-dimensional crimps are developed. Is a fiber that does not substantially advance.

[Example 1]
Using only the fiber 1, a known granular cotton manufacturing apparatus was used to obtain granular cotton having a diameter of 3 mm to 8 mm and made of the fiber 1.
From the obtained granular cotton composed of fiber 1, 3 g of granular cotton was weighed. The weighed granular cotton was uniformly placed in a case (length x width x height: 50 mm x 150 mm x 30 mm) made of a metal net. The case filled with granular cotton was placed in a constant temperature dryer set at 100 ° C. and heat-treated at 100 ° C. for 10 minutes to develop spiral three-dimensional crimping in the fibers 1 constituting the granular cotton. After 10 minutes, the case was taken out from the constant temperature dryer, cooled sufficiently at room temperature, and then the granular cotton molded product was taken out from the metal net case, and the granular cotton molded product of Example 1 (length x width x height: 48 mm × 140 mm × 24 mm) was obtained.

[Examples 2 to 5] and [Comparative Examples 4 to 5]
Examples 2 to 5 and Comparative Examples 4 to 5 were different from the above-mentioned method for producing a granular cotton molded product of Example 1 except that the heat treatment was performed under the heat treatment conditions (temperature and time) shown in Tables 1 and 2. Using the same method, granular cotton molded products of Examples 2 to 5 and granular cotton molded products of Comparative Examples 4 to 5 were obtained. However, in Comparative Example 4, since the fiber 1 did not sufficiently develop three-dimensional crimping even after the heat treatment, there was confounding due to the occurrence of three-dimensional crimping, but the integration of granular cotton occurred with the occurrence of three-dimensional crimping. It was in a state where the granular cotton was easily loosened.

[Comparative Example 1]
The fiber 2 and the fiber 3 are prepared, the fiber 2 and the fiber 3 are weighed so that the mass ratio (fiber 2 / fiber 3) is 70/30, and the diameter is 3 mm to 3 mm using a known granular cotton manufacturing apparatus. Granular cotton having a size of 8 mm and in which fibers 2 and 3 were mixed was obtained.
3 g of granular cotton was weighed from the obtained granular cotton in which the fibers 2 and 3 were mixed. Using the metal mesh case used in Example 1, the granular cotton was treated under the same heat treatment conditions as in Example 1, and the granular cotton molded product of Comparative Example 1 (length x width x height: 50 mm x 150 mm x 30 mm). ) Was obtained.

[Comparative Examples 2-3]
Comparative Examples 2 and 3 were heat-treated under the fibers and heat treatment conditions (temperature and time) shown in Table 2, except that the method was the same as the method for producing a molded product of the granular cotton molded product of Comparative Example 1 described above. Was used to obtain granular cotton molded articles of Comparative Examples 2 and 3.

Regarding the granular cotton molded products of Examples and Comparative Examples thus obtained, the density of the molded products, the number of crimps of the crimpable composite fibers, the presence or absence of entanglement due to the development of spiral crimps, the presence or absence of heat fusion, The magnitude of breaking strength, bulk recovery rate and tactile sensation were evaluated.

[Density of molded product]
For the volume of the molded body, the volume of the molded body was calculated from the average value of the values measured at three points for each of the three sides of length, width, and height using a straightedge made of metal. The mass of the molded product was measured with a precision balance. The measured mass was divided by volume to give the density of the part.

[Number of crimps of crimpable composite fibers]
The number of crimps of the crimpable composite fiber in which three-dimensional crimps were manifested was measured using SEM photographs taken to investigate the following [entanglement due to the expression of three-dimensional crimps] and [heat fusion]. First, from the SEM photograph taken, a portion where a wavy fiber shape that repeats peaks and valleys or a coiled fiber shape is clearly expressed is searched for. Next, for the part where the wavy or coiled fiber shape is clear, the number of apex parts (also called mountain parts) of the crimp is measured, and the length of the repeating part of the valley and the mountain part including the mountain part is counted. Measure from the scale. From the measured number of ridges and the length of the fiber containing the number of ridges, the number of crimps when converted to a length of 25 mm was obtained, and the number of crimps of the observed crimpable composite fiber was obtained. did. The number of crimps was calculated by counting the number of crimps at 10 points and calculating the average value.

[Confounding due to steric crimp expression] and [Heat fusion]
The presence or absence of confounding and the presence or absence of heat fusion due to the expression of three-dimensional crimping of the granular cotton molded product were examined by observing with a scanning electron microscope (SEM). The SEM photographs of the granular cotton molded articles of Examples 1 to 3 are shown in FIGS. 4A to 6B, and the SEM photographs of the granular cotton molded articles of Comparative Examples 1 to 5 are shown in FIGS. 7A to 11B. In each case, FIG. A is 30 times and FIG. B is 200 times. The accelerating voltage of each SEM is 10 kV. The results are shown in Tables 1-2.

Wavy or spiral crimps occur when the fibers are finely wavy or when the fibers are rolled up. In this case, "confounding due to the expression of steric crimp" is considered to be "yes".
On the other hand, when the fibers do not have a fine wavy shape or are not wound so roundly, it is considered that the three-dimensional crimping does not occur so much. In this case, "confounding due to the expression of steric crimp" is considered to be "absent".
Further, when melting is not observed at the contact points between the fibers, it is considered that heat fusion has not occurred. In this case, the "heat fusion status" is considered to be "none".
On the other hand, when melting is observed at the contact points between the fibers, it is considered that heat fusion has occurred. In this case, the "heat fusion status" is considered to be "yes".

[Breaking strength]
Clips having a grip width of 63 mm are attached to both ends of the longest side (140 mm side in Example 1) of the granular cotton molded product. Clip the clip at one end of the part to the stand so that the part can hang from the stand. Fasten the plate on which the weight is placed to the other clip. Gradually place the weight on the plate on which the weight hanging below the molded body is placed. When the weight of the weight is increased and the elongation of the granular cotton molded product becomes large to some extent, the weight to be added is 1 g each, and when the weight is added, the elongation of the granular cotton does not stop and the plate when the molded product breaks. And the breaking strength is calculated from the total weight of the weight. The results are shown in Tables 1-2.
When the breaking strength is 0.03 N or more, it is considered that the granular cotton is integrated into a molded product of granular cotton.

[Bulk recovery rate]
The bulk recovery rate was measured for each of the granular cotton compacts of Examples 1 to 5 and Comparative Examples 1 to 5 by the following procedure.
Place each granular cotton molded product on a horizontal table with the largest surface as the bottom surface. After measuring the height of the granular cotton molded product, a weight of 820 g is placed on the granular cotton molded product and left for 30 minutes. After 30 minutes, the "mold height (B) before weight removal" was measured. Then, the weight on the molded product is removed, and the product is left to stand for 30 minutes. After 30 minutes had passed, the height of the molded product was measured again and used as "the height of the molded product after weight removal (C)".
The bulk recovery rate is expressed by the following formula.
Bulk recovery rate (%) = (CB) x 100 / C
[Here, B: sample height before weight removal, C: sample height after weight removal]
The results are shown in Tables 1-2.
When the bulk recovery rate is 5% or more and 98% or less, when compressed by applying an external force, not only is it likely to be soft to the touch because it is deformed moderately, but it is also easy to return to its original shape when pressure is removed. ,preferable.

[Tactile]
The tactile sensation was measured using the granular cotton molded product used for measuring the bulk recovery rate. The results are shown in Tables 1-2.
When three-dimensional crimping occurs without heat fusion and the granular cotton is integrated to obtain a granular cotton molded product, there is a tactile sensation having elasticity like stickiness. On the other hand, when heat fusion occurs, it has a hard and rough feel. The evaluation criteria for tactile sensation are as follows.
◯: It has stickiness like stickiness when pressed and also has excellent elasticity.
Δ: There is a slight stickiness when pressed, and it also has elasticity.
×: There is no stickiness when pressed, and no elasticity is felt.

The granular cotton molded products of Examples 1 to 5 were obtained by heating granular cotton made of fiber 1 at a temperature of 100 to 135 ° C. for 10 minutes. When these were observed with a scanning electron microscope (SEM), a portion where the fiber was spirally wound was observed, and the presence of three-dimensional crimp was confirmed. For example, FIGS. 4A, 5A and 6A show SEM photographs (10 kV, 30 times) of the molded articles of Examples 1 to 3, respectively. In each case, a coiled or spirally wound portion is observed, and the existence of three-dimensional crimping can be understood.

Further, in the granular cotton molded products of Examples 1 to 5, even when observed by SEM, it was not possible to find a portion fused between the fibers. For example, FIGS. 4B, 5B and 6B show SEM photographs (10 kV, 200 times) of the molded articles of Examples 1 to 3, respectively. In any case, since it was not possible to find a fused portion between the fibers, it is considered that the fibers were not substantially heat-sealed.

Since the breaking strength of each of the granular cotton molded products of Examples 1 to 5 is 0.03 N or more, it is considered that the granular cotton of Examples 1 to 5 is integrated without being adhered. Since the bulk recovery rate is 5% or more, it is easy to return to the original shape by releasing the load after compressing by applying a load, and it is easy to recover the bulk of the granular cotton molded product. Is considered to be. In addition, the tactile sensations were all ◯, which were excellent.

The granular cotton molded products of Comparative Examples 1 to 3 were obtained by heating granular cotton made of fiber 2 at a temperature of 100 to 125 ° C. for 10 minutes. When these were observed by SEM, no rounded parts were observed, and the presence of three-dimensional crimps was not confirmed. For example, FIGS. 7A, 8A and 9A show SEM photographs (10 kV, 30 times) of the granular cotton molded articles of Comparative Examples 1 to 3, respectively. None of them could understand the existence of three-dimensional crimping.

Further, in the granular cotton molded product of Comparative Example 1, when observed by SEM, it was not possible to find a portion fused between the fibers. On the other hand, in the granular cotton molded products of Comparative Examples 2 and 3, it was possible to find a heat-sealed portion between the fibers. For example, FIGS. 7B, 8B and 9B show SEM photographs (10 kV, 200 times) of the granular cotton molded articles of Comparative Examples 1 to 3, respectively. In FIG. 7B, no portion was found to be fused between the fibers, but in FIGS. 8B and 9B, a location where heat was fused between the fibers could be observed. .. Therefore, it is considered that the granular cotton molded products of Comparative Examples 2 and 3 are heat-sealed.

Since the granular cotton molded product of Comparative Example 1 was neither integrated by three-dimensional crimping nor integrated by heat fusion, both the breaking strength and the bulk recovery rate were not sufficient and could not be measured.
The granular cotton molded product of Comparative Example 2 was integrated by heat fusion and was excellent in breaking strength and bulk recovery rate, but the tactile sensation was poor without feeling chewy.
The granular cotton molded product of Comparative Example 3 was integrated by heat fusion and was excellent in breaking strength and bulk recovery rate, but the tactile sensation was not sticky and was hard and poor in elasticity, which was not desirable.

The granular cotton molded articles of Comparative Examples 4 and 5 were obtained by heating granular cotton made of fiber 1 at 80 or 145 ° C. for 10 minutes. When the granular cotton molded product of Comparative Example 4 was observed by SEM, it appeared that three-dimensional crimping occurred and heat fusion did not occur (see FIGS. 10A to 10B). The breaking strength was not sufficient, the granular cotton was not integrated, and the tactile sensation was not chewy. Further, when the granular cotton molded product of Comparative Example 5 was observed by SEM, three-dimensional crimping occurred and heat fusion occurred (see FIGS. 11A to 11B), and it is considered that the granular cotton was integrated. It was. The molded product of Comparative Example 5 has excellent breaking strength, but the bulk recovery rate is at an unmeasurable level, and the fibers constituting the molded product are firmly adhered to each other by a heat-melted thermoplastic resin. Because it is hard, it lacks elasticity, and the tactile sensation was not desirable.

The present invention provides a molded product that can be used as various batting materials, cushioning materials, cushioning materials, etc., and is integrated without adhering granular cotton. They are preferably excellent in feel, texture, handleability and the like.

The present specification includes the following embodiments.
1. 1.
A granular cotton molded product in which granular cotton is integrated without being adhered by entanglement of fibers constituting the granular cotton.
A granular cotton molded product in which, in a joint portion between granular cottons constituting the granular cotton molded product, at least a part of the fibers constituting the joint portion contains fibers expressing three-dimensional crimping.
2.
The granular cotton molded product according to 1 above, wherein at least a part of the three-dimensional crimp is contained in the fiber expressing the three-dimensional crimp.
3. 3.
The granular cotton molded product according to 1 or 2 above, wherein the number of crimps of the fiber expressing the three-dimensional crimp is 20 to 500 fibers / 25 mm.
4.
The granular cotton molded product according to any one of 1 to 3 above, wherein the granular cotton molded product contains at least 30% by mass or more of fibers expressing the three-dimensional crimp.
5.
The fiber expressing the three-dimensional crimp is a composite fiber containing at least two kinds of components, a first component and a second component.
The first component contains a thermoplastic resin and constitutes at least 20% of the fiber surface.
The second component contains a thermoplastic resin having a melting point higher than the melting point of the thermoplastic resin contained in the first component.
The composite fiber is at least one selected from an eccentric core sheath type composite fiber and a parallel type composite fiber in which the position of the center of gravity of the second component deviates from the position of the center of gravity of the composite fiber in the fiber cross section. The granular cotton molded product according to any one of 1 to 4.
6.
In the composite fiber, the first component contains 50% by mass or more of a propylene copolymer or an ethylene-α-olefin copolymer, and the second component is polypropylene, polymethylpentene, polyethylene terephthalate, or polytrimethylene terephthalate. The granular cotton molded product according to 5 above, which contains 50% by mass or more of at least one thermoplastic resin selected from the group consisting of polybutylene terephthalate and polybutylene terephthalate.
7.
An article selected from clothing supplies, bedding, furniture and packaging materials, which comprises the granular cotton molded article according to any one of 1 to 6 above.
8.
It is selected from a cushioning material, a pad, a cushioning material, a sound absorbing material, a sound insulating material, a vibration isolating material, a vibration damping material, a heat insulating material and a heat insulating material, including the granular cotton molded product according to any one of 1 to 7 above. material.
9.
Prepare granular cotton containing latent crimpable composite fibers capable of developing three-dimensional crimps;
Fill the container with granular cotton so that it is dense enough to contact each other;
The latent crimpable composite fiber is subjected to a manifestation treatment for expressing three-dimensional crimp, and the latent crimpable composite fiber is subjected to three-dimensional crimping;
At the contact portion where the granular cotton filled in the container is in contact with each other, the fibers of the adjacent granular cotton are entangled due to the occurrence of three-dimensional crimping, and the granular cotton in the container is integrally molded without being adhered. To be a body
A method for producing a granular cotton molded product, including.
10.
9. The method for producing a granular cotton molded product according to 9 above, wherein the latent crimpable composite fiber contains a heat-sensitive latent crimpable composite fiber that develops three-dimensional crimping by heating.
11.
The heat-sensitive latent crimpable composite fiber contains at least two components, a first component and a second component.
The melting point of the thermoplastic resin contained in the second component is higher than the melting point of the thermoplastic resin contained in the first component.
When the melting point of the thermoplastic resin containing the first component and Tf ₁ ° C., the manufacturing method of the granular cotton molded article according to 10 above, wherein the heat treatment is performed at _Tf 1 -50～Tf less than ₁ (° C.).

Claims (8)

A granular cotton molded product in which granular cotton is integrated without being adhered by entanglement of fibers constituting the granular cotton.
In the joint portion between the granular cottons constituting the granular cotton molded product, at least a part of the fibers constituting the joint portion contains fibers expressing three-dimensional crimping .
The fiber expressing the three-dimensional crimp is a composite fiber containing at least two kinds of components, a first component and a second component.
The first component contains 50% by mass or more of a propylene copolymer having a melting peak temperature of 145 ° C. or lower, and constitutes at least 20% of the fiber surface.
The second component contains a thermoplastic resin having a melting point higher than the melting point of the propylene copolymer contained in the first component.
The composite fiber is at least one selected from an eccentric core sheath type composite fiber and a parallel type composite fiber in which the position of the center of gravity of the second component deviates from the position of the center of gravity of the composite fiber in the fiber cross section.
The number of crimps of the fiber expressing the three-dimensional crimp is 70 to 500 fibers / 25 mm.
Granular cotton molding. The granular cotton molded product according to claim 1, wherein in the fiber expressing the three-dimensional crimp, at least a part of the three-dimensional crimp includes a spiral crimp. Said particulate cotton compacts comprising said fibers expressing a three-dimensional crimp of at least 30 wt% or more, particulate cotton molded article according to claim 1 or 2. In the composite fiber, the first component contains 50% by mass or more of a propylene copolymer which is at least one selected from a propylene-ethylene copolymer and a propylene-1-butene-ethylene copolymer . Any one of claims 1 to 3, wherein the two components contain 50% by mass or more of at least one thermoplastic resin selected from the group consisting of polypropylene, polymethylpentene, polyethylene terephthalate, polytrimethylene terephthalate and polybutylene terephthalate. The granular cotton polymer according to the section . The granule according to any one of claims 1 to 4, wherein in the composite fiber, the second component contains polypropylene, and either or both of the first component and the second component contains a polyolefin-based elastomer. Cotton molded body. An article selected from clothing supplies, bedding, furniture and packaging materials, which comprises the granular cotton molded article according to any one of claims 1 to 5 . Selected from cushioning material, pad, cushioning material, sound absorbing material, sound insulating material, vibration isolating material, vibration damping material, heat insulating material, and heat insulating material, including the granular cotton molded product according to any one of claims 1 to 6. Material. A granular cotton containing at least two components, a first component and a second component, and containing a heat- sensitive latent crimpable composite fiber that develops three-dimensional crimping by heating .
The first component contains 50% by mass or more of a propylene copolymer having a melting peak temperature of 145 ° C. or lower, and constitutes at least 20% of the surface of the heat-sensitive latent crimpable composite fiber.
The second component contains a thermoplastic resin having a melting point higher than the melting point of the propylene copolymer contained in the first component.
The heat-sensitive latent crimpable composite fiber is selected from at least an eccentric core sheath type composite fiber and a parallel type composite fiber in which the position of the center of gravity of the second component deviates from the position of the center of gravity of the composite fiber in the composite fiber cross section. Prepare one type of granular cotton ;
Fill the container with granular cotton so that it is dense enough to contact each other;
When the melting point of the propylene copolymer included in the first component and Tf ₁ ° C., Tf 1 _-50 or more, at a temperature Tf below ₁ (° C.), the latent crimpable conjugate fiber, expressed steric crimps The latent crimpable composite fiber is subjected to a three-dimensional crimping treatment so that the number of crimps is 70 to 500 pieces / 25 mm ; and the granular cotton filled in the container comes into contact with each other. Manufacture of a granular cotton molded body, which comprises entanglement of adjacent granular cotton fibers due to the occurrence of three-dimensional crimping at the contact portion, and integrating the granular cotton in the container into a molded body without being adhered. Method.