KR20200077152A - Process for producing polyolefin conjugate spinning fiber with high spinning property, bulkiness and softness - Google Patents

Abstract

The present invention relates to a method for producing a polyolefin conjugate spinning fiber, and more specifically, to a method for producing a polyolefin conjugate spinning fiber with high spinning properties, bulkiness and softness. The method for producing a polyolefin conjugate spinning fiber according to the present invention includes the step of conjugate-spinning a first component and a second component by setting a polypropylene resin as the first component and a mixture of a polypropylene resin and a low density polyethylene resin as the second component. Since it is possible to produce a polyolefin conjugate spinning fiber with high spinning properties, bulkiness and softness, the polyolefin conjugate spinning fiber can be effectively used to manufacture a parallel-type, peanut-type, or eccentric-type conjugate spinning nonwoven fabric.

Description

Manufacturing method of polyolefin composite spinning fiber with excellent spinning, bulkiness and flexibility{PROCESS FOR PRODUCING POLYOLEFIN CONJUGATE SPINNING FIBER WITH HIGH SPINNING PROPERTY, BULKINESS AND SOFTNESS}

The present invention relates to a method for producing a polyolefin composite spinning fiber, and more particularly, to a method for producing a polyolefin composite fiber excellent in spinning, bulkiness and flexibility.

With regard to non-woven fabrics for sanitary materials used as materials for diapers and sanitary napkins for infants, interest in non-woven fabrics that are soft and flexible to satisfy a consumer's fit is growing, while meeting the strength properties required of conventional non-woven fabrics for sanitary materials and soft feel. There is a need for a non-woven fabrication technology and material technology capable of realizing.

Traditionally, polypropylene has been widely used as a non-woven material due to its excellent strength and fiber spinning properties.However, in order to further improve the feel, bulkiness, and flexibility of the existing polypropylene non-woven fabric, the content of high density polyethylene or alpha olefin comonomer is mainly contained in polypropylene. Studies have been conducted to prepare a nonwoven fabric by mixing a polyolefin-based elastomer of 5% or more.

However, if the mixing ratio of the high-density polypropylene or olefin comonomer content mixed with polypropylene is less than 8% of the polyolefin-based elastomer is 5% or more, it is difficult to impart improved tactile feel, bulkiness and flexibility to the nonwoven fabric, and the mixing ratio is 8%. If it is abnormal, there is a problem in that it is difficult to provide a high-quality non-woven fabric because the spinning property is significantly lowered.

As a solution to this, a composite spinning fiber in which two polymers having different physical and chemical structures are independently bonded, that is, two polymers are bonded side-by-side (parallel, peanut-shaped) or one polymer Research has been conducted to manufacture nonwoven fabrics by spinning fibers in a form surrounding other polymers (core sheath type, eccentric type).

The parallel type, peanut type, eccentric type, and core type composite fibers are polypropylene composed of polypropylene as the first component and polymers having different physical and chemical structures as the second component or polymers having different physical and chemical structures. Is used.

In the case of parallel, peanut, or eccentric composite fibers, crimping is imparted to the fibers due to the difference in swelling power and thermal viscosity of the first and second components, and bulkiness can be improved when manufactured from a nonwoven fabric. have. When the first component and the second component are the same as polypropylene, bulkiness may be limitedly limited by a difference in melting point and a difference in melting index.

In addition, in the case of the core-sheath type composite fiber, it is used to give improved fiber strength compared to the conventional polypropylene sole spinning fiber, or it is used to obtain a special surface compared to polypropylene, and this can be used to manufacture a non-woven fabric with improved feel.

However, since the chemical structure of the first-component polypropylene and the second-component polymer is significantly different between the parallel-type and the peanut-type composite fibers, when there is insufficient compatibility between the two polymers and the interconnection is insufficient, the physical properties in the fiber stretching process or the post-processing process There is a problem that the fiber interface is separated by the phosphorus force.

Republic of Korea Patent Publication No. 10-2003-0052313 (published on June 27, 2003) relates to a parallel hollow composite spinning nonwoven fabric, the first component is composed of high-density polyethylene, the second component is composed of polypropylene, and the hollow ratio is Although it discloses a non-woven fabric made of 20-30% parallel hollow composite spinning fibers, the first component polyethylene and the second component polypropylene have low compatibility, and the fiber interface is caused by physical force in the stretching process or post-processing process. There is a problem of separation.

Republic of Korea Patent Publication No. 10-2012-0113896 (published on October 16, 2012) relates to a core-sheath composite spinning non-woven fabric, the core portion is composed of a mixture of polypropylene and polyolefin-based elastomer, sheath ( The sheath) part is composed of high density polyethylene and discloses a method of manufacturing a nonwoven fabric having an improved tactile feel, but it is difficult to improve the bulkiness of the nonwoven fabric, and there is a problem that the polypropylene composition and the polyethylene composite spinning fiber interface are easily separated.

Republic of Korea Patent Publication No. 10-2003-0071869 (published on September 6, 2003) relates to a core-sheath type or a parallel-type composite spinning nonwoven fabric, the first component is composed of a polypropylene homopolymer, and the second component has an ethylene comonomer content. Consisting of 0-10% mole of polypropylene ethylene random copolymer, the first component polypropylene has a melting point of 20°C or higher higher than that of the second component polypropylene random copolymer as measured by differential scanning calorimetry (DSC). Although a non-woven fabric is disclosed, characterized in that the component ratio of the second component polymer is 30/70 to 5/95, there is a need for a non-woven fabric material having better bulkiness and flexibility commercially.

Republic of Korea Patent Publication No. 10-2014-0065898 (published on May 30, 2014) relates to a parallel, peanut-type, eccentric composite spinning nonwoven fabric, wherein the first component and the second component are composed of polypropylene, and the first component and The polypropylene melt index ratio (first component/second component) of the second component is 1.3 to 2.6, and a polypropylene composite spinning nonwoven fabric having bulkiness is disclosed, but a commercially available nonwoven fabric having better bulkiness and flexibility Is required.

Japanese Patent Application Publication No. 1993-033218 (published on Feb. 09, 1993) relates to a parallel composite spinning split fiber, wherein the first component is composed of polypropylene, and the second component is composed of a mixed composition of polypropylene and polyethylene, Disclosed is a polyolefin-based split fiber characterized in that it is arranged in parallel so that the contact length of the first component and the second component is 0.95 to 1.10 times the fiber diameter, but not a composition with improved bulkiness and flexibility. not.

Japanese Patent Publication No. 2004-522868 (published on July 29, 2004) relates to a bonding layer type non-woven fabric, wherein the first component is composed of polypropylene, and the second component is polypropylene (core component) and polyethylene (sheath component). A nonwoven fabric composed is disclosed, but a composition having improved bulkiness is not disclosed.

Republic of Korea Patent Publication No. 10-2012-0113896 Republic of Korea Patent Publication No. 10-2003-0071869 Republic of Korea Patent Publication No. 10-2003-0071869 Republic of Korea Patent Publication No. 10-2014-0065898 Japanese Patent Publication No. 1993-033218 Japanese Patent Publication No. 2004-522868

The present invention is to solve the above problems, polypropylene-based resin as a first component, a mixture of polypropylene-based resin and low-density polyethylene-based resin as a second component, the first component and the second component An object of the present invention is to provide a method for producing a polyolefin composite fiber having excellent spinnability, bulkiness, and flexibility, comprising the step of compound spinning.

The present invention (a) polypropylene-based resin as a first component, (b) polypropylene-based resin 81 to 99% by weight and (c) low-density polyethylene-based resin 1 to 19% by weight of the mixture containing the second component As described above, there is provided a method of manufacturing a polyolefin composite fiber comprising the step of complex spinning the first component and the second component through each nozzle.

In addition, the present invention provides a composite spinning nonwoven fabric comprising a polyolefin composite fiber produced by the method for producing the polyolefin composite fiber.

The polyolefin composite spinning fiber manufacturing method according to the present invention comprises a polypropylene-based resin as a first component, a mixture of a polypropylene-based resin and a low-density polyethylene-based resin as a second component, and the first component and the second component. By including the step of composite spinning, it is possible to manufacture a composite spinning fiber having excellent spinnability, bulkiness and flexibility, and thus can be usefully used to manufacture a parallel, peanut, or eccentric composite spinning nonwoven fabric.

Hereinafter, the present invention will be described in more detail.

In the present invention, when a part “includes” a certain component, it means that the component may further include other components, not to exclude other components, unless otherwise stated.

<Polyolefin composite fiber manufacturing method>

One aspect of the invention,

(a) a polypropylene-based resin as a first component, (b) a polypropylene-based resin containing 81 to 99% by weight and (c) a low-density polyethylene-based resin containing 1 to 19% by weight as a second component, It is a method for producing a polyolefin composite fiber comprising the step of complex spinning the first component and the second component through each nozzle.

The term "composite spinning" as used herein refers to fibers formed by combining multiple extrudates into each fiber or filament resulting in two or more separate sections occupied by separate polymer components along the entire length of the fiber or filament. Or it means to produce a filament, and the cross-section of the fiber can take several arrangements, such as side-by-side, peanut, and eccentric.

(a) First component polypropylene resin

In the method for producing a polyolefin composite fiber according to the present invention, the first component compositely spun is polypropylene-based resin.

The first component polypropylene-based resin according to the present invention may be preferably a polypropylene-based homopolymer from the viewpoint of emphasizing the strength or heat resistance of the fiber or nonwoven fabric. In addition, the first component polypropylene-based resin according to the present invention is preferably a propylene polymer copolymerized in a content of 0.1 to 10 mol% of propylene and an alpha-olefin having 2 to 20 carbon atoms from the viewpoint of emphasizing flexibility of fibers or nonwoven fabrics. It may be, more preferably, a propylene polymer copolymerized with propylene and an alpha-olefin having 2 to 20 carbon atoms in a content of 2 to 7 mol%. Specifically, when the content of the alpha-olefin is more than the above range, excellent flexibility is imparted, and if it is less than the above range, a decrease in the fiber cooling rate during spinning is suppressed, so that non-woven web formation is excellent.

The first component polypropylene-based resin according to the present invention, from the viewpoint of improving the non-woven spinning workability, the molecular weight may preferably be 100,000 ~ 250,000 g / mol, more preferably 120,000 ~ 230,000 g / mol, Most preferably, it may be 140,000 to 200,000 g/mol. Specifically, if the molecular weight is above the above range, the mechanical properties of the nonwoven fabric are excellent, and if it is below the above range, the spinning workability is excellent.

The first component polypropylene-based resin according to the present invention, from the viewpoint of improving the non-woven spinning workability, the molecular weight distribution (Mw / Mn) may be preferably 5 or less, more preferably 3.5 or less, most preferably 3.0 or less. Specifically, when the molecular weight distribution is less than the above range, swelling of the polymer melted at the die ejection opening during fiber spinning is suppressed to ensure uniform spinning workability.

(b) Second component polypropylene resin

In the method for producing a polyolefin composite fiber according to the present invention, the second component that is compound spun is 81 to 99% by weight of a polypropylene-based resin, preferably 85 to 95% by weight. Specifically, if the content of the second component polypropylene-based resin is above the above range, the spinning workability is excellent, and if it is below the above range, the mixing ratio of the second component polyethylene-based resin is high, and the first component polypropylene-based resin is excellent in melting. The difference in tension is given.

The type, molecular weight, molecular weight distribution, etc. of the second component polypropylene-based resin according to the present invention are as described in the first component polypropylene-based resin.

(c) Second component low density polyethylene-based resin

In the method for producing a polyolefin composite fiber according to the present invention, the second component compositely spun contains 1 to 19% by weight of a low density polyethylene-based resin, preferably 5 to 15% by weight. Specifically, when the content of the second component low-density polyethylene-based resin is more than the above range, a difference between the first component polypropylene-based resin and excellent melt tension is imparted, and if it is less than the above range, the spinning workability is excellent.

In the second component that is spun in the method for producing the polyolefin composite fiber according to the present invention, (b) polypropylene-based resin and (c) low-density polyethylene-based resin are present as a mixture, the mixture is the first component ( a) It is distinct from polypropylene-based resins.

The second component low-density polyethylene-based resin according to the present invention provides a thermal characteristic difference between the mixture of the second component (b) and (c) and the first component (a), and is easy to maximize the difference in melt tension. , The density may preferably be 0.910 to 0.925 g/cm 3, more preferably 0.910 to 0.920 g/cm 3, and most preferably 0.910 to 0.916 g/cm 3.

The second component low-density polyethylene-based resin according to the present invention provides a thermal characteristic difference between the mixture of the second component (b) and (c) and the first component (a), and is easy to maximize the difference in melt tension. , The viscosity average molecular weight (Mz) may be preferably 400,000 to 700,000 g/mol, more preferably 500,000 to 700,000 g/mol, and most preferably 550,000 to 650,000 g/mol. Specifically, when the viscosity average molecular weight (Mz) is more than the above range, an excellent melt tension difference is imparted, and if it is less than the above range, spinning workability is excellent.

(d) Third component low crystalline polypropylene resin

In the method of manufacturing the polyolefin composite fiber according to the present invention, the second component, which is spun from the composite spinning, preferably has low crystallinity with respect to 100 parts by weight of the components (b) and (c) in terms of improving bulkiness and flexibility of the nonwoven fabric. A polypropylene-based resin may further be included as an additive to the second component. The low crystalline polypropylene resin is preferably 1 to 9 parts by weight, more preferably 3 to 9 parts by weight, most preferably 5 to 9 parts by weight based on 100 parts by weight of the components (b) and (c) It can be included as a wealth. Specifically, if the content of the third component low crystalline polypropylene-based resin is more than the above range, the flexibility and bulkiness are improved, and if it is below the above range, commercial economics is excellent.

The third component low crystalline polypropylene-based resin according to the present invention may preferably be polymerized under a metallocene-based catalyst.

The third component low crystalline polypropylene-based resin according to the present invention may preferably be a propylene homopolymer. In addition, the third component low crystalline polypropylene-based resin according to the present invention may preferably be a propylene polymer copolymerized with propylene and an alpha-olefin having 2 to 20 carbon atoms in an amount of 5 mol% or less. Specifically, when the content of the alpha-olefin is less than the above range, the spinning performance is excellent due to compatibility with the second component polypropylene resin.

The third component low crystalline polypropylene-based resin according to the present invention may have an isotacticity (Pentad II, mmmm) value of preferably 20 to 70%, more preferably 20 to 60%, , Most preferably 30 to 60%. Specifically, the general isotactic polypropylene resin has a value of 95% or more [mmmm]. Due to the high degree of crystallinity, the nonwoven fabric has excellent strength but poor flexibility, and the general atactic polypropylene is It has a value of 10% or less [mmmm], and has very low crystallinity, so that mechanical properties are remarkably low, it is easy to deform, and it is difficult to use as a non-woven fabric due to its adhesiveness. Therefore, if the stereoregularity of the third component low crystalline polypropylene-based resin according to the present invention is greater than or equal to the above range, adhesiveness is lowered, and if it is less than the above range, excellent soft feel of the nonwoven fabric is imparted. .

The third component low-crystalline polypropylene-based resin according to the present invention, from the viewpoint of improving the non-woven spinning workability, the molecular weight may preferably be 100,000 to 250,000 g/mol, more preferably 120,000 to 230,000 g/mol day It may be, most preferably 140,000 ~ 200,000 g / mol.

The third component low crystalline polypropylene-based resin according to the present invention, from the viewpoint of improving the non-woven spinning workability, the molecular weight distribution (Mw/Mn) may be preferably 5 or less, more preferably 3.5 or less, most Preferably it may be 3.0 or less. Specifically, when the molecular weight distribution is less than the above range, the expansion phenomenon of the polymer melted at the die outlet during fiber spinning is suppressed to ensure uniform spinning workability.

The polyolefin composite fiber produced by the method for manufacturing the polyolefin composite fiber according to the present invention is compounded in parallel at 5 denier (g/9000m), spinning speed of 2,400 m/min, for 1 hour, preferably, the yarn is shaken This does not occur and there may be no single yarn occurrence.

In addition, the polyolefin composite fiber produced by the method for manufacturing the polyolefin composite fiber according to the present invention has a desirable degree of crimp when the filament yarn 90 cm produced by spinning with a parallel composite spinning molding machine is heat treated at 100°C and 5 min. Preferably, the filament yarn has an apparent length of less than 87 cm, more preferably the filament yarn has an apparent length of less than 84 cm, and most preferably the filament yarn has an apparent length of less than 81 cm.

In addition, the polyolefin composite fiber produced by the method for producing the polyolefin composite fiber according to the present invention has a flexural modulus measured according to the ASTM D790 method, preferably less than 16,000 kgf/cm 2, more preferably less than 15,000 kgf/cm 2, most Preferably, it may be less than 14,000 kgf/cm 2.

In the polyolefin composite fiber manufactured by the method for producing the polyolefin composite fiber according to the present invention, fiber interface separation may not occur in the stretching process or the post-processing process.

The terms or words used in the specification and claims should not be interpreted as being limited to the ordinary or dictionary meanings, and the inventor can appropriately define the concept of terms in order to best describe his or her invention. Based on the principle of being present, it should be interpreted as meanings and concepts consistent with the technical spirit of the present invention. Therefore, since the parallel, peanut, and eccentric composite spinning methods do not represent all of the technical ideas of the present invention, it should be understood that there are various equivalents and modifications that can replace them according to the cross section of the thread.

<Composite spinning non-woven fabric>

Another aspect of the present invention is a composite spinning non-woven fabric comprising a polyolefin composite fiber produced by a method for producing a polyolefin composite fiber according to the present invention.

The production of the composite spinning nonwoven fabric according to the present invention may be performed through a conventional staple fiber process and a spunbond process, for example, after manufacturing and spinning the polyolefin resin composition of the composite spinning into filament fibers having a predetermined thickness by melt spinning and stretching. It can be produced by laminating the web and thermally bonding or needle punching the laminated filament web.

The composite spinning non-woven fabric according to the present invention may preferably have a fineness of 1 to 5 denia (g/9000m).

The composite spinning nonwoven fabric according to the present invention may preferably have a basis weight of 8 to 80 g/m 2.

Hereinafter, examples will be described in detail to specifically describe the present specification. However, the embodiments according to the present specification may be modified in various other forms, and the scope of the present specification is not interpreted to be limited to the embodiments described below. The embodiments of the present specification are provided to more fully describe the present specification to those skilled in the art. In addition, "%" and "part" which represents content below are on a weight basis unless otherwise specified.

Examples and Comparative Examples: Preparation of polyolefin composite fiber

The compositions of Examples 1 to 4 and Comparative Examples 1 to 3 were prepared with the composition and content of the components shown in Table 1 below. Specifically, the composition of the first component or the second component was thoroughly mixed in a Henschel mixer for 7 minutes at 800 rpm, and then pelletized polyolefin using a 40 mm single screw extruder with L/D 35 in the range of 180-230°C. Based resin composition was prepared. At this time, in Example 2, Example 4, and Comparative Example 3, a third component was added as an additive of the second component, and the content of the third component was mixed based on parts by weight of the second component. Thereafter, the prepared first component and second component pellet-shaped resin compositions were spun to produce a filament by spinning in a parallel composite spinning molding machine.

Category (unit: parts by weight) Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 1st ingredient (a) Polypropylene type
Suzy 100 100 100 100 100 100 100 Second ingredient (b) Polypropylene
Suzy 95 95 90 90 100 80 90 (c) low density
Polyethylene resin 5 5 10 10 0 20 10 Third component (d) low crystallinity
Polypropylene resin
(Based on 100 parts by weight of the second component) 0 5 0 5 0 0 10

Experimental Example

The composite fibers prepared according to the above Examples and Comparative Examples were evaluated by the following method, and the results are shown in Table 2 below.

[Assessment Methods]

1) Radioactivity: Compared to the yarn frequency and yarn tremors generated during one hour of operation by parallel spinning at 5 denier (g/9000m) and spinning speed of 2,400m/min, A, B, C, and D are compared. It was evaluated in order.

A: There is no thread tremor and no single yarn is generated.

B: Thread tremor does not occur, but 1 to 2 strand single yarn occurs

C: There is a fine thread tremor, and 3 to 4 strands of yarn are generated.

D: Thread tremor is very severe, and more than 5 strands of single yarn are generated.

2) Bulkiness: When the filament yarn 90cm was heat treated at 100°C and 5 min, it was evaluated in the order of A, B, C, and D according to the degree of crimp generation of the filament.

A: filament yarn apparent length less than 81cm range

B: filament yarn apparent length more than 81cm ~ less than 84cm

C: filament yarn apparent length is more than 84cm and less than 87cm

D: filament yarn apparent length 87cm or more range

3) Flexibility: Flexural modulus was measured according to ASTM D790 and evaluated in order of A, B, C, and D according to the degree of flexibility.

A: Range of flexural modulus less than 14,000 kgf/㎠

B: Flexural modulus 14,000 kgf/㎠ or more ~ less than 15,000 kgf/㎠

C: Range of flexural modulus more than 15,000 kgf/cm2 ~ less than 16,000 kgf/cm2

D: Range of flexural modulus over 16,000 kgf/㎠

division Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 characteristic Radioactive A A A A A D D Bulky castle B B A A D A A flexibility C B B A D A A

As a result, as shown in Table 2, the first component polypropylene-based resin, the second component polypropylene-based resin and low-density polyethylene-based resin, and the third component low-crystalline polypropylene-based polyolefin-based resin containing the optimum composition It was found that the polyolefin composite fiber prepared by complex spinning the resin composition has improved spinning, bulkiness and flexibility.

Claims (11)

(a) a polypropylene-based resin as a first component, (b) a polypropylene-based resin containing 81 to 99% by weight and (c) a low-density polyethylene-based resin containing 1 to 19% by weight as a second component, A method for producing a polyolefin composite fiber comprising the step of complex spinning the first component and the second component through each nozzle. According to claim 1,
The (a) polypropylene-based resin or (b) polypropylene-based resin is a propylene homopolymer or a propylene polymer copolymerized with propylene and an alpha-olefin having 2 to 20 carbon atoms in a content of 0.1 to 10 mol%, and having a molecular weight of 100,000 to Method of producing a polyolefin composite fiber, characterized in that the molecular weight distribution (Mw/Mn) is 5 or less, and 250,000 g/mol. According to claim 1,
The (c) low-density polyethylene-based resin has a density of 0.910 to 0.925 g/cm 3, and a viscosity average molecular weight (Mz) of 400,000 to 700,000 g/mol. According to claim 1,
The mixture (b) and (c) a method for producing a polyolefin composite fiber, characterized in that it further comprises 1 to 9 parts by weight of low crystalline polypropylene resin with respect to 100 parts by weight of the component. According to claim 4,
The low crystalline polypropylene resin is a polymer polymerized with a metallocene catalyst, and is a propylene homopolymer or a propylene polymer copolymerized with propylene and an alpha-olefin having 2 to 20 carbon atoms in a content of 5 mol% or less, and the stereoregularity is also [mmmm]. Method of producing a polyolefin composite fiber, characterized in that the value is 20 to 70%, and the molecular weight distribution (Mw/Mn) is 5 or less. According to claim 1,
The polyolefin composite fiber produced by the method for manufacturing the polyolefin composite fiber is compounded in parallel in a condition of 5 denier (g/9000m) and spinning speed of 2,400 m/min. Method for producing a polyolefin composite fiber, characterized in that there is no. According to claim 1,
The polyolefin composite fiber produced by the method for producing the polyolefin composite fiber has a degree of crimp when the filament yarn 90 cm produced by spinning at a parallel composite spinning molding machine is heat-treated at 100°C and 5 min for an apparent length of 87 cm. Method for producing a polyolefin composite fiber, characterized in that less than. According to claim 1,
A method for producing a polyolefin composite fiber, wherein the polyolefin composite fiber produced by the method for producing the polyolefin composite fiber has a flexural modulus of less than 16,000 kgf/cm 2 measured according to the ASTM D790 method. According to claim 1,
The polyolefin composite fiber produced by the method for producing the polyolefin composite fiber is a method for producing a polyolefin composite fiber characterized in that the fiber interface separation does not occur in the stretching process or post-processing process. A composite spinning nonwoven fabric comprising a polyolefin composite fiber prepared by a method for manufacturing the polyolefin composite fiber of any one of claims 1 to 9. The method of claim 10,
The composite-spun non-woven fabric has a fineness of 1-5 deniers (g/9000m), and a composite-spun non-woven fabric characterized in that the basis weight is 8-80 g/㎡.