JPH09310258A - Molding product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive nonwoven fabric, a knitted or a woven fabric and a molding product, comprising thermally fused fibers and having a soft touch feeling of the nonwoven fabric, knitted or woven fabric without hardening bonded parts where the thermally fused fibers are thermally fused and hardly causing permanent set by fatigue even when a repetitive compression load is applied thereto. SOLUTION: This molding product comprises a nonwoven fabric obtained by mixing at least 10wt.% conjugated fiber staple, comprising a component A, covering and enclosing at least >=60% periphery of a cross section of the conjugated fiber with a polypropylene, prepared by polyblending a syndiotactic polypropylene with an isotactic polypropylene, comprising at least >=55wt.% syndiotactic pentad component and good in crystallinity and a component B having the higher melting point than that of the component A by >=20 deg.C. Otherwise, the molding product comprises a knitted or a woven fabric prepared by mixing at least 20wt.% conjugated fiber staples therein.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded article made of a knitted woven fabric and a non-woven fabric made of spun yarn containing a heat fusion binder fiber.

[0002]

2. Description of the Related Art Many heat fusion fibers have been proposed.
For example, Japanese Patent Application Laid-Open No. 1-111016 proposes a composite fiber having a sheath portion obtained by polyblending crystalline polypropylene with 1 to 15% by weight of octene-1 which is a copolymer of ethylene and octene-1, and polyethylene terephthalate as a core portion. Has been done. Normal low density polyethylene (LDP
E) or high density polyethylene (HDPE) sheathed composite fiber has a hard adhesive part when heat-sealed, and the texture of the nonwoven fabric, knitted fabric, etc. made from it becomes hard, and it is also settled by compression due to repeated load. It has an easy defect. This proposal attempts to improve the drawback, but it requires a complicated process of polyblending the copolymer, and has an economically disadvantageous disadvantage of using expensive octene-1 as the copolymerization component. It was

Further, Japanese Unexamined Patent Publication (Kokai) No. 5-163654 proposes a nonwoven fabric using a composite fiber in which an elastomer composed of a block copolymer of polybutylene terephthalate and polytetramethylene glycol is used in a sheath portion and polyethylene terephthalate is used in a core portion. However, the polymer of this sheath portion is expensive, and this proposal also has a disadvantage that is economically disadvantageous.

On the other hand, as a novel polypropylene fiber, Japanese Patent Application Laid-Open No. 3-82814 discloses a syndiotactic pentad fraction of 0.7 or more and a thickness of 10,000 to 1000.
Fibers that are 0.1 denier have been proposed. It is said that this fiber has a high tensile strength, but in the example, it is 480 g at 370 denier, which is far smaller than the strength of 5 g / denier of general polyethylene terephthalate fiber. In addition, there is no description of a composite fiber in this proposal, and there is no description of use as a heat-sealing fiber.

Further, as a new polypropylene composite fiber, Japanese Patent Application Laid-Open No. 4-327211 proposes a composite fiber containing one component of polypropylene having a syndiotactic pendant fraction of 0.5 or more. The proposed composite fiber only discloses an example in which a homopolymer is used as a method for increasing the syndiotactic pendant fraction to 0.5 or more. However, when composite spinning is performed using only syndiotactic polypropylene, sticking during spinning is remarkable,
There was a serious drawback of not being able to spin multifilaments.

[0006]

DISCLOSURE OF THE INVENTION The object of the present invention is not to harden the heat-sealed bonded portion of the heat-sealed fiber, and the texture of the nonwoven fabric or knitted fabric made of it is soft, and even if repeated compression load is applied The present invention provides a difficult, inexpensive non-woven fabric, knitted fabric, and molded article.

[0007]

[Means for Solving the Problems] The inventors of the present invention have formed a molded article using a composite heat-bonding fiber containing a syndiotactic polypropylene as a sheath component, which is an inexpensive polymer having flexibility and good spinnability. In particular, research on compression molded products has led to the completion of the present invention. That is, in the present invention, polypropylene having 55% by weight or more of syndiotactic pentad component (hereinafter, abbreviated as "SPP") covers at least 60% or more of the cross section of the composite fiber,
At least 10 composite fiber staples comprising the enclosing A component and the B component having a melting point higher than the A component by 20 ° C. or more.
A molded article comprising a non-woven fabric mixed by weight% and a knitted woven fabric mixed by at least 20 weight%.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The melting point of typical polypropylene is around 160 ° C. This polypropylene is an isotactic polypropylene with the pentad methyl groups on the same side. This polypropylene has high crystallinity and poor flexibility. On the other hand, SPP has a melting point of around 140 ° C., low crystallinity, and high flexibility. On the other hand, SPP also shows rubber-like properties.

The SPP manufacturing method has already been described in J. A. EWEN
Discovered by J. et al. Am. Chem. Soc. ,
1989, 110, 6255. This is a production method using an asymmetric transition metal catalyst and a catalyst composed of aluminoxane. For example, isopropyl (cyclopentadienyl-1-fluorenyl) as a transition metal catalyst
Hafnium dichloride, isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dichloride and the like are listed. The general formula of aluminoxane is R- (A
10) nAl-R or cyclic (R-AlO) n, (wherein R represents a hydrocarbon group having 1 to 3 carbon atoms), and particularly R is a methyl group and n is 5 to 5. 10 items are often used.

The SPP polymerization method using this catalyst is not particularly limited, and a solution polymerization method, a bulk polymerization method, a gas phase polymerization method or the like can be used. Usually, pressure polymerization is performed.

The syndiotactic pentad component ratio of the SPP used in the present invention can be measured by 13 C-NMR. Moreover, it can be easily estimated by IR and DSC. This SPP contains the syndiotactic pentad component in an amount of 55% by weight or more. 5
If it is less than 5% by weight, the adhesion point after heat fusion becomes too hard, and the crystallization rate of polypropylene decreases. On the other hand, 75
If the content is more than weight%, the sticking during spinning may become severe.
It is preferably 55 to 75% by weight. This SPP is IP
By polyblending with P, the syndiotactic pendant component ratio of SPP can be changed. SPP
Only with this, the sticking at the time of spinning is remarkable and the multifilament cannot be spun. This is SPP only and SPP
This is due to the difference between the polyblend of PEG and IPP.
Since the polyblend dissolves in the macro while separating into the micro, it behaves as a homopolymer in the micro part. I
PP is much more crystalline than SPP. Therefore, even with the same syndiotactic pendant fraction, the crystallinity of the polyblend is better than that of SPP alone. This is important for preventing sticking during spinning.

The molecular weight of SPP used in the present invention may be any molecular weight suitable for melt spinning. Further, it can be adjusted by depolymerization with a peroxide which is generally used for adjusting the molecular weight. In the melt spinning of the composite fiber, it is preferable that the viscosities of the components A and B at the spinning temperature are close to each other because spinning is easy. The spinning temperature is mainly adjusted to maintain the tenacity, for example, the polymer of the core component, and the molecular weights of the other components are preferably adjusted to an appropriate viscosity at that temperature. The spinning viscosity of general melt spinning is 0.1 to 30, preferably 1 to 15.
It is. This melt viscosity is a JIS value in which the orifice weight is 2 mm and the load weight is 2.14 kg, and the outflow weight per minute is g.
It is the value measured by the method.

Further, the above SPP may be copolymerized with a small amount of another vinyl comonomer such as ethylene within a range that does not inhibit sticking during spinning. Further, various stabilizers, for example, an ultraviolet stabilizer, a heat resistance stabilizer, a crystallization accelerator, and a flame retardant, a matting agent, a pigment, an antibacterial agent, an antifungal agent and the like can be added and used.

The method for spinning the composite fiber may be melt spinning using a general composite spinneret. That is, with an extruder,
Components B are separately melted, combined with a composite spinneret, melt-spun, and cooled with cooling air. After being cooled, oiled,
It is wound up as undrawn yarn. The melt-spun yarns are bundled, stretched, oiled, crimped, and cut to produce staples.

In spinning using SPP, it is important to prevent sticking during spinning. Therefore, it is necessary to supply sufficient cooling air during spinning. Especially when the thickness of monofilament is large,
Moreover, caution is required when the size of the fiber bundle is large. Single denier less than 5 denier and total denier 15
If it is 0 denier or less, cooling air of 15 to 20 ° C may be used, but if it exceeds 10 ° C, it may be 15 ° C or less, preferably 10 ° C.
It is preferable to carry out spinning at a temperature of not higher than 0.degree. C., and sometimes not higher than 5.degree.

In the composite spinning using SPP, at least 60% or more of the cross section of the composite fiber is surrounded by SPP.
Must be covered and wrapped. The wrapping prevents the SPP from separating from the part that retains its strength. Separation eliminates the characteristics of composite fibers and mimics the mixing of separate fibers. In the case of separate fibers, the size of the melted portion is larger than that of the composite fiber, and the heat fusion effect is small.

The polymer of the part that retains the strength of the conjugate fiber must have a melting point higher than the melting point of SPP by 20 ° C. or more. If the difference in melting point is small, heat fusion occurs, and strict temperature control is required during molding, which is not practical. For example, polyethylene terephthalate, polybutylene terephthalate, nylon 6, nylon 1
2. Isotactic polypropylene and the like.

A spun yarn can also be produced by blending the above-mentioned composite fiber staple used in the present invention. The spinning method is not particularly limited. Commonly used short spinning, soft wool spinning,
It can be manufactured by woolen spinning, semi-woolen spinning, air spinning, binding spinning and the like. The blending ratio of the composite fiber of the spun yarn is preferably 20% by weight or more. If it is less than 20% by weight, the workability during molding is lowered. It is preferably 50% by weight or more, more preferably 80% by weight or more. In addition to the above-mentioned composite fibers, ordinary heat-sealing fibers can be used in combination, but they are not very advantageous in terms of economy or physical properties of products and should be limited to special applications.

The method for producing the nonwoven fabric used in the present invention is not particularly limited. After carding, which is generally used, a method of needle punching, thermal bonding, an air laying method, or a wet papermaking method can be used. When manufacturing this nonwoven fabric, it is necessary to manufacture it so that the tensile strength and elongation in the machine direction and the cross direction do not differ greatly. If the tensile strength and elongation in the machine direction and the cross direction are greatly different, unevenness in drawing tends to occur parallel to the direction in which tensile strength and elongation are strong, and unevenness in product thickness is likely to occur. The difference in tensile strength and elongation is preferably 30% or less, more preferably 15% or less. If the difference in tensile strength and elongation exceeds 30%, the thickness unevenness of the molded product may become large.
Be especially careful when squeezing deeply. It is preferable that the stress-strain curves in the machine direction and the cross direction are the same.

In the case of a non-woven fabric, a good heat-sealing effect and moldability can be exhibited with a mixing ratio of 10% by weight or more, which is smaller than that of spun yarn. In both spun yarn and non-woven fabric, the heat-sealing effect increases as the mixing ratio of the conjugate fiber of the present invention increases.
The twisting of the spun yarn can be set at 40 ° C. or higher, but 80 ° C. or lower is preferable. If it is lower than 40 ° C, the set may be insufficient, and if it exceeds 80 ° C, the texture may be hard and the knitting property may be deteriorated.

Further, a knitted fabric used in the present invention using the above spun yarn can be manufactured. The method for manufacturing the knitted fabric is not particularly limited. It can be knitted by a general circular knitting machine, a tricot knitting machine, or the like. Just match the gauge and thread thickness. Alternate knitting and double-sided knitting are also possible. Further, the method for manufacturing the woven fabric is not particularly limited. It can be woven with a general loom. For example, it can be woven by an automatic power loom, a rapier loom, an air jet loom, a water jet loom, or the like. It can be used for both warp and weft of textiles.
Also, by selecting a loom, double weave or mesh weave like moquette can be performed.

The molded product of the present invention can be manufactured by drawing such as molding. The molding may be preheated but may not be preheated. In addition, by making a difference in temperature between the male and female molds during molding, the degree of heat fusion on the low temperature side can be reduced and fluffing can be achieved. This temperature difference is preferably 30 ° C. or more. By heating the mold only on the back side where fluffing occurs, a temperature difference occurs between the back surface and the front surface, and the surface does not reach the temperature for heat fusion, so that fluffing can be performed.

Further, since the temperature and the pressure exert a synergistic effect, it is possible to reduce the degree of heat fusion and fluff by partially reducing the pressure. This pressure difference can be achieved by partially lowering the contact pressure by making a difference in the mold clearance. When the contact pressure is partially increased and heat fusion is performed, it is possible to reduce the deterioration in wear resistance, which is a drawback due to fuzzing. In addition, it is possible to add a pattern to increase the added value. The pattern may be an embossed pattern. The temperature difference between the back surface and the surface depends on the thermal conductivity coefficient and the thickness of the nonwoven fabric. It is advisable to combine the above factors as appropriate depending on the desired degree of fluffing. The tensile strength of the molded product of the present invention can be adjusted by the basis weight of the nonwoven fabric, the number of fibers, the mixing ratio of the heat-sealing fibers, the molding temperature during drawing, the clearance of the molding die, and the like.

The molded product of the present invention can be made into a molded product composed of a pile of fiber bundles by using a Delois type non-woven fabric in which needle punching is performed from only one direction. When the molded product of the present invention is a molded product, the basis weight is preferably 100 to 300 g / m ² . If the basis weight is less than 100 g / m ² , the strength is insufficient, and if the basis weight exceeds 300 g / m ² , deep drawing becomes difficult. This is not the case in general compression molding. The density of the molded product of the present invention is 0.01 to 0.4 g / cm.
^Although it is ³ , when fluffing, the density of the surface becomes smaller and has a distribution in the thickness direction. In addition, the molded product of the present invention may be reinforced by laminating a drawable layer such as a film or an unstretched filament long-fiber nonwoven fabric on the back surface. Furthermore, the molded article of the present invention can be given a pattern by printing it on a non-woven fabric, a film or the like in advance.

[0025]

The molded article of the present invention is melted by heat and has a flexible bonding point, so that the molded article made of the non-woven fabric and the knitted fabric has a soft texture. Therefore, even when the molded product is deformed, the adhesive points are less likely to break and come off. This is a very important point when the molded product is repeatedly bent or compressed and used. When the bonding point is hard, the bonding point is destroyed by use and is reduced, so that the set becomes large. On the other hand, the molded article of the present invention has a small settling.

[0026]

【Example】

Production Example 1 Isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dicloside was used as a polymerization catalyst, and the average degree of polymerization was 1.
Using 6 methylaluminoxane at 1: 150 at 20 ° C
After pressure polymerization for 2 hours in a conventional manner, deashing treatment and washing with hydrochloric acid, SPP having a syndiotactic pentad component content of 89% by weight was produced. Next, peroxide is added to depolymerize and adjust the viscosity, and then Ca stearate and 2,6-di-t-butylphenol are added as additives to produce chips having a melt viscosity of 12 and isotactic to this SPP. Polypropylene was polyblended with a kneader to change the blending ratio and used as the sheath component A of the composite fiber.

As the core component B of the composite fiber, the melt viscosity is 11,
Using polyethylene terephthalate with a melting point of 255 ° C., 3
The components A and B were separately melted with an extruder at 00 ° C., weighed with a gear pump, and a core-sheath type composite spinneret was used to spin an unstretched composite yarn with a composite ratio of 1: 1 by a standard method.
The temperature of the cooling air was 5 ° C. to prevent sticking. Next, the unstretched yarn bundle was bundled, stretched 3.3 times at 120 ° C., crimped, and then oiled and cut to manufacture a composite fiber staple 1.5 denier 51 mm.

Similarly, the test No. 1 to 4 composite fiber and test No. The undrawn yarn of each of the comparative products of 5 was manufactured, the discharge amount was changed, and the spinning total denier was gradually increased to compare the total denier at which sticking in spinning occurred.
The results are shown in Table 1. The temperature of the cooling air was set to 20 ° C. for easy comparison. In addition, a chip of component A was hot pressed to form a film test piece having a thickness of 100 μm and a width of 10 mm, and the bending resistance in the machine direction was compared according to the cantilever method (JIS L1096). The thickness error was corrected by calculation, and the test No. Based on 2, relative comparison was made in units of%. Test No. The comparative product of 5 was too hard.

[0029]

[Table 1]

Example 1 Manufacturing Example 1 No. The composite fiber staple of 1.5 denier 51 mm produced in 4 and the commercially available polyethylene terephthalate staple of 1.5 denier 51 mm were mixed and spun at a ratio of 1/80 by changing the composite fiber mixing ratio. Next, the tricot was knitted with a 48-gauge tricot knitting machine, and drawn with a molding machine at 180 ° C. The depth that can be uniformly squeezed was measured by changing the mold, and the results are shown in Table 2.
It was shown to.

[0031]

[Table 2]

Example 2 Test No. 3 denier of the composite fiber of the present invention (1.5 denier) and commercially available polyethylene terephthalate staple (1.5 denier 51 mm) were mixed, carded, cross-laid, needle punched at a number of 40 / cm ² by a conventional method, and mixed rate Was changed to produce a nonwoven fabric having a basis weight of 300 g / m ² . Mold temperature of this non-woven fabric is 1 using a molding machine.
It was drawn at 80 ° C. The depth that can be uniformly squeezed is 0.
Table 3 shows the results of the maximum depth that can be uniformly molded by changing the mold every 5 cm.

[0033]

[Table 3]

Example 3 In the same manner as in Example 1, the core polymer of the component B had a melting point of 15
Copolymer of propylene and ethylene at 2 ℃ (comparative product)
Then, spinning was performed by changing to isotactic polypropylene (invention) having a melting point of 162 ° C., and the results were compared. Using this staple, the test No. Similar to 11 300
A g / m ² non-woven fabric was produced. This non-woven fabric was drawn by a molding machine at a mold temperature of 160 ° C. The molded product of the present invention could be uniformly molded at a depth of 1.5 cm, but the comparative product became a film. When the mold temperature was lowered to 150 ° C, the comparative product broke.

Example 4 Test No. 2 of Example 2 In the same manner as in 12, the nozzle shape of the composite spinneret was changed to cover at least 60% of the periphery of the cross section of the composite fiber, and to enclose the composite staple of the present invention, and the coverage of the periphery of the cross section was 5.
A 0% side-by-side staple (comparative) was produced. When carded in the same manner as in Example 2, the components A and B were separated in the comparative product, but the components A and B were not separated in the nonwoven fabric of the composite fiber used in the present invention. Next, it was drawn by a mold forming machine at a mold temperature of 160 ° C. The molded product of the present invention could be uniformly molded at a depth of 1.5 cm. The comparative product broke.

Example 5 Test No. 2 of Example 2 The same as 12
A non-woven fabric of g / m ² was produced, preheated at 180 ° C. for 5 minutes, and then press-formed to a thickness of 20 mm. The compression residual strain rate of 80,000 times of the molded article of the present invention was measured according to JIS K-6401, and was 3%. On the other hand, a commercially available heat fusion-bonded composite fiber and a molded product using "Belcombi" (trade name) manufactured by Kanebo Co., Ltd. whose sheath component is copolyester have a residual strain rate of 12.3% at 80,000 times. It was

Example 6 Test No. 1 of Example 1 A spun yarn of No. 9 was used as a double yarn, a plain weave fabric was produced with 80 yarns / 25 mm, and was drawn and molded at a mold temperature of 180 ° C. by a molding machine. The molded product could be uniformly molded at a depth of 1.5 cm.

[0038]

EFFECTS OF THE INVENTION The molded article of the present invention is inexpensive, has excellent mechanical strength, has a flexible heat-sealed adhesive portion, and has a soft texture, and the adhesive point is unlikely to drop off even after repeated compression, and is unlikely to be easily set. .

Claims (2)

[Claims] 1. A polyblend of syndiotactic polypropylene and isotactic polypropylene, wherein the syndiotactic pentad component is at least 55% by weight and the polypropylene having good crystallinity is at least 60% of the cross section of the conjugate fiber. A molded article made of a non-woven fabric, which is obtained by mixing at least 10% by weight of the composite fiber staple which covers the above-mentioned surroundings and wraps around the A component and the B component having a melting point higher than the A component by 20 ° C. or more. 2. A polyblend of syndiotactic polypropylene and isotactic polypropylene, wherein the syndiotactic pentad component is at least 55% by weight and the polypropylene having good crystallinity is at least 60% of the cross section of the composite fiber. A molded article made of a knitted woven fabric, which is obtained by mixing at least 20% by weight of the composite fiber staple which covers the surroundings and wraps around the A component and the B component having a melting point of 20 ° C. or more higher than that of the A component.