TWI798257B - Complex-fiber for the compressing molding body and manufacturing method thereof - Google Patents

Abstract

The present invention relates to fibers used in compression moldings and a method for producing the same, more particularly, to a bicomponent composite fiber excellent in formability and shape stability, and a method for producing the same.

Description

Composite fiber for compression molded article and method for producing the same

The present invention relates to a composite fiber which can provide an applied product excellent in mechanical properties in relation to formability and shape stability, and a method for producing the same at high yield.

In general, applied products of fiber aggregates such as nonwovens have been used for various purposes such as hygiene, medical, agricultural or industrial purposes, etc., and especially, in the case of nonwoven fabrics for industrial purposes, the tensile strength is very Important factor. In order to meet these requirements and obtain a product with high tensile strength, a method of increasing the weight per unit area for production is generally used. However, in the case of production by increasing the weight as described above, since the thickness of the product also increases at the same time, there is a problem that it is difficult to apply to products requiring both small thickness and toughness.

Therefore, products having mechanical properties similar to or higher than those of plastic products are manufactured by compensating for insufficient mechanical properties of applied products using fiber aggregates by mixing and blending glass fibers, carbon fibers, etc. with other fibers and sales. However, in the case of products using such glass fibers, there is a problem in that glass fibers are detached from the product and scattered during the processing process to pollute the working environment. Also, glass fibers are reported to cause lung cancer, and therefore, recently, demands for developing products having physical properties equivalent to or higher than those using glass fibers without using glass fibers are increasing.

(Prior art literature) (patent documents)

(Patent Document 1) Korean Patent No. 10-0899613 (authorization date: 2009.5.20)

(Patent Document 2) Korean Patent No. 10-1357018 (authorization date: 2014.01.23)

The present invention was developed in order to solve the above-mentioned problems. Conjugate fibers for application products such as fiber aggregates with good dispersibility, etc., and provide a method for producing the above-mentioned conjugate fibers with high commerciality.

In order to achieve the above object, the composite fiber of the present invention is a bicomponent fiber comprising a first component resin and a second component resin, wherein the first component resin may comprise a polyester resin, and the second component resin may comprise a crystal For the permanent polyolefin resin, the temperature difference between the melting point of the first component resin and the second component resin can be 30~100°C.

In a preferred embodiment of the present invention, during differential thermal analysis (DSC), the enthalpy value required for dissolving crystals of the above-mentioned crystalline polyolefin resin may be 40-120 J/g.

In a preferred embodiment of the present invention, the above-mentioned first component resin may include a polyester resin with an intrinsic viscosity of 0.50-1.00 dl/g and a melting point of above 200°C. Polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polytrimethylene terephthalate (PTT) resin and polyethylene naphthalate One or more kinds of glycol ester (polyethylene naphthalate; PEN) resins.

In a preferred embodiment of the present invention, the above-mentioned polyethylene terephthalate resin may include a polymer formed by polymerizing terephthalic acid and diol in a molar ratio of 1:0.95-1.20.

In a preferred embodiment of the present invention, the above-mentioned second component resin may include a crystalline polyolefin resin with a melting point of 150-170° C., and the above-mentioned crystalline polyolefin resin may include polypropylene (polypropylene; PP) resin and one or more of polyethylene resins.

In a preferred embodiment of the present invention, the above-mentioned bicomponent composite fibers can be sheath-core (sheath-core) type fibers, side-by-side (side-by-side) type fibers, sea-islands (sea-islands) type fibers or split ( segmented-pie) type fiber.

In a preferred embodiment of the present invention, the cross-sectional area ratio of the first component and the second component of the above-mentioned bicomponent composite fiber may be 1:0.5~1.

In a preferred embodiment of the present invention, the above-mentioned two-component composite fiber can be a sheath-core fiber, wherein the sheath can include a crystalline polyolefin resin with a melting point of 150-170°C, and the core can include a polyolefin resin with a melting point of 200°C or higher. Polyethylene terephthalate resin.

In a preferred embodiment of the present invention, the average fineness of the composite fiber of the present invention may be 4-12 de, the average fiber length may be 3-120 mm, and the number of crimps may be 9-15 per inch.

In a preferred embodiment of the present invention, the surface of the composite fiber of the present invention may be modified, or a hydrophilic coating and/or a hydrophobic coating may be formed on the surface of the composite fiber.

Another object of the present invention relates to the preparation method of the composite fiber described above, the preparation method of the composite fiber may include: step 1, preparing polyester chips and crystalline polyolefin chips respectively; step 2, melting the polyester chips respectively The first component resin and the second component resin formed with crystalline polyolefin chips are put into a composite spinning nozzle for composite spinning, and then cooled to prepare an unstretched sub-tow (sub-tow); step 3 , stretching the above-mentioned unstretched sub-filament bundles, and then imparting crimps (crimp); and step 4, heat-fixing and cutting (cutting) the stretched and crimped sub-filament bundles.

In a preferred embodiment of the present invention, the aforementioned sub-filament bundles may be sheath-core monofilaments, side-by-side monofilaments, island-in-the-sea monofilaments or segmented monofilaments.

In a preferred embodiment of the present invention, in step 2, the melting of the polyester chip can be carried out at a temperature of 270-300°C, and the melting of the crystalline polyolefin chip can be carried out at a temperature of 230-280°C.

In a preferred embodiment of the present invention, in step 2, composite spinning can The spinning temperature is 260~290°C and the winding speed is 400~1,300m/min.

Still another object of the present invention is to provide a fiber aggregate produced using the above-mentioned conjugate fiber of the present invention.

In a preferred embodiment of the present invention, the above-mentioned fiber aggregate may be a non-woven fabric.

In a preferred embodiment of the present invention, the above-mentioned nonwoven fabric can be a dry-laid nonwoven fabric, a wet-laid nonwoven fabric or an air-laid nonwoven fabric. non-woven fabric.

Still another object of the present invention is to provide a compression-molded article produced by stacking the above-mentioned fiber aggregates in one or more layers, followed by compression-molding.

In a preferred embodiment of the present invention, the compression molded product may further include a fiber aggregate layer containing fibers having a component different from the fiber component constituting the above fiber aggregate.

The composite fiber of the present invention has excellent physical properties such as tensile strength, flexural strength, and flexural modulus, has good adhesion between composite fibers, and is excellent in processability, and is therefore suitable for applications requiring high mechanical properties and sound absorption at the same time. Fiber aggregate application products such as performance, sound dispersibility, moisture absorption and water dispersibility.

FIG. 1 is a scanning electron microscope (SEM) photograph of a cross section of a compression molded article produced in Preparation Example 1. FIG.

FIG. 2 is a SEM photograph of a cross-section of a compression molded article prepared in Preparation Example 2. FIG.

FIG. 3 is an SEM photograph of a cross section of a compression molded article prepared in Preparation Example 3. FIG.

Fig. 4 and Fig. 5 are respectively the morphological stability measurement results of Preparation Example 1, Preparation Example 2 and Preparation Example 3 implemented in Experimental Example 2.

Next, the conjugate fiber of the present invention will be described in more detail.

The composite fiber of the present invention is a bicomponent fiber comprising a first component resin and a second component resin, and may be a sheath-core fiber, a side-by-side fiber, an island-in-the-sea fiber or a split fiber, preferably, may be a sheath Core fiber or side-by-side fiber.

The above-mentioned first component resin is related to the shape stability of fiber aggregates such as nonwoven fabrics and the like prepared using the conjugate fibers of the present invention and compression-molded articles using the fiber aggregates, and therefore, it is preferable to use resins having excellent modulus. resin. Furthermore, it is preferable to use a material suitable for ensuring the form stability and moldability of the fiber aggregate and/or the compression-molded product by ensuring the adhesiveness with the conjugated fiber as the second component resin.

Moreover, in the composite fiber of the present invention, the melting point temperature difference between the first component resin and the second component resin may be 30 to 100°C, preferably 40 to 90°C. At this time, if the melting point temperature difference If the temperature is less than 30°C, when the composite fiber is used to prepare the fiber aggregate, in order to realize the bonding between the composite fibers through the second component resin, it is necessary to prepare the fiber aggregate under an appropriate temperature atmosphere so that the second component resin is properly formed. Melts, but since the first component resin becomes soft due to the small melting point temperature difference between the first component resin and the second component resin, it may cause a decrease in the mechanical properties of fiber aggregates and compression molded products using fiber aggregates Furthermore, processability and formability deteriorate. If the difference in melting point temperature is greater than 100°C, the compatibility between the first-component resin and the second-component resin will decrease instead because the temperature difference between the resins becomes unnecessarily large, so it may be difficult to prepare a two-component resin. The problem of sub-composite fibers.

The above-mentioned first component resin may include a polyester resin, and the above-mentioned polyester resin may include polyethylene terephthalate resin, polybutylene terephthalate resin, polytrimethylene terephthalate resin, and polyethylene terephthalate resin. Ethylene naphthalate resin, preferably, can include one selected from polyethylene terephthalate resin, polybutylene terephthalate resin and polyethylene naphthalate resin The above, more preferably, may include polyethylene terephthalate resin.

Moreover, the intrinsic viscosity of the above-mentioned polyester resin may be 0.50~1.00dl/g and the melting point may be above 200°C. Preferably, the intrinsic viscosity may be 0.55~0.90dl/g and the melting point may be 230°C. ~280°C, more preferably, the intrinsic viscosity may be 0.60~0.75dl/g and the melting point may be 240~265°C. At this time, if the intrinsic viscosity of the polyester resin is less than 0.50dl/g, there may be a problem that the toughness of the conjugated fiber will decrease, and if the intrinsic viscosity of the polyester resin is greater than 1.00dl/g, there may be problems with spinning and drawing workability. Lowering the problem. Also, if the melting point of the polyethylene terephthalate resin is less than 200°C, the temperature difference between the melting point and the second component resin becomes too small, and there may be processing problems when manufacturing application products using composite fibers. Therefore, it is preferable to use a polyethylene terephthalate resin having the above-mentioned melting point.

Moreover, when the polyester resin is a polyethylene terephthalate resin, a polyethylene terephthalate resin commonly used in the art can be used, preferably, a mole ratio of 1:0.95 to 1.20 can be used Polyethylene terephthalate resin, a polymer obtained by polymerizing terephthalic acid and diol in proportion.

Next, the above-mentioned second component resin may include a polyolefin resin.

As the above-mentioned crystalline polyolefin resin, one or more selected from polypropylene resin and polyethylene resin can be used, preferably, polypropylene resin can be used.

Furthermore, in differential thermal analysis, the enthalpy required for dissolving crystals of the above-mentioned crystalline polyolefin resin may be 40-120 J/g, preferably 70-115 J/g.

Moreover, the melting point of the above-mentioned crystalline polyolefin resin may be 150-170°C, preferably 155-170°C, more preferably 160-170°C, at this time, if the melting point of the crystalline polyolefin resin is less than 150°C, the temperature difference between the melting point and the polyester resin as the first component resin becomes too large, and the spinnability of the two-component composite fiber used to prepare it decreases, and the first component resin and the second component The compatibility between the resins is reduced, so it is difficult to prepare two-component composite fibers, and if the melting point of the crystalline polyolefin resin is greater than 170°C, the temperature difference between the melting point of the first component resin and the second component resin becomes small , resulting in a problem of reduced workability.

Moreover, the above-mentioned composite fiber is a composite fiber composed of two components, and the cross-sectional area ratio of the first component and the second component of the fiber may be 1:0.5~1, preferably 1:0.7~1. At this time, if the cross-sectional area ratio of the second component is less than 0.5, there may be a problem that the binding force between the composite fibers decreases, and if the cross-sectional area ratio of the second component is greater than 1, the area of the first component becomes Relatively small, so the tenacity of the composite fiber is reduced, and there may be a modulus of products made using the composite fiber reduced problem.

In a preferred embodiment of the composite fiber of the present invention, the composite fiber of the present invention may be a sheath-core composite fiber, wherein the sheath may include a crystalline polyolefin resin with a melting point of 150-170° C., and the core may include a polyolefin resin with a melting point of 200° C. Polyethylene terephthalate resin above ℃.

Moreover, the average fineness of the composite fiber of the present invention can be 4~12de, the average fiber length can be 3~120mm, the number of crimps can be 9~15/inch, preferably, the average fineness can be 5~10de, the average fiber length It can be 6~100mm, the number of crimps can be 10~14/inch, more preferably, the average fineness can be 5~9de, the average fiber length can be 20~100mm, and the number of crimps can be 10~14/inch. At this time, if the average fineness of the conjugated fibers is less than 4de, there may be a problem of reduction in the tensile strength of fiber aggregates and/or compression moldings, and if the average fineness of the conjugated fibers is greater than 12de, there may be fiber aggregates and/or The problem of the reduction of the modulus of a compression molding. Also, the fiber length of the conjugate fiber may be applied varying according to products manufactured using the conjugate fiber. Moreover, if the number of crimps is less than 9/inch, the elasticity and bulkiness of the composite fiber may be deteriorated, and if the number of crimps is more than 15/inch, there may be increased neps during carding ( nep) problem.

The conjugate fiber of the present invention may be provided with functionality by modifying the surface of the fiber, or a hydrophilic coating and/or a hydrophobic coating may be formed on the surface of the conjugate fiber.

The toughness of the composite fiber of the present invention can be more than 3.5g/d, the elongation can be more than 55%, the initial modulus of elasticity can be more than 3.2g/d, the shrinkage rate can be 5.0~6.5%, and the number of crimps can be 9~ 15/inch, preferably, the tenacity of the composite fiber of the present invention can be more than 3.70～4.10g/d, and elongation can be more than 57～62%, and initial modulus of elasticity can be more than 3.2～3.8g/d, shrinkage The rate can be 5.4~6.2%, and the number of crimps can be 10~14/inch.

In the case where the composite fiber of the present invention is a sheath-core type composite fiber, when measured based on ASMT D790, a compression molded article made of a sheath-core type composite fiber at a relative humidity of 50% and a temperature of 23°C The bending strength can be above 5.5MPa and the bending elastic modulus can be above 430MPa, preferably, the bending strength can be 7.4~12MPa and the bending elastic modulus can be 480~700MPa, more preferably, the bending strength can be 9.5~11.5MPa and The flexural modulus can be 508~620MPa.

Also, in the case where the composite fiber of the present invention is a sheath-core type composite fiber, when measured based on ASMT D638, the compressed fiber made of the sheath-core type composite fiber is compressed at a relative humidity of 50% and a temperature of 23°C. The tensile strength of the formed product may be 18.5 MPa or more, preferably 20-27 MPa, more preferably 20.2-23.5 MPa.

The composite fiber of the present invention as described above can be produced by a process comprising: step 1, separately preparing a polyester chip and a crystalline polyolefin chip; step 2, melting the polyester chip and a crystalline polyolefin chip, respectively The first component resin and the second component resin formed by the polyolefin chip are put into the composite spinning nozzle for composite spinning, and then the undrawn sub-filament bundle is prepared by cooling; step 3, the above-mentioned undrawn sub-filament The bundle is stretched, and then crimped; and step 4, heat fixing and cutting the stretched and crimped sub-filament bundles.

The characteristics, types, etc. of the polyester chip of the above-mentioned step 1 are the same as those of the first component resin described above, and the characteristics, types, etc. of the above-mentioned crystalline polyolefin chip are the same as those of the second component resin described above. The characteristics and types of the resins are the same, and the above-mentioned polyester chip and crystalline polyolefin chip are chips made of the above-mentioned first component resin and second component resin.

In step 2, the melting of the polyester core can be performed at a temperature of 270-300°C, and the melting of the crystalline polyolefin core can be performed at a temperature of 230-280°C.

The composite spinning in step 2 can be carried out at a spinning temperature of 260-290°C and a winding speed of 400-1,300m/min, preferably at a spinning temperature of 265-285°C and winding The speed is 500~1,200m/min. At this time, if the spinning temperature is less than 260°C, the internal pressure of the pack may increase and the spinning workability may decrease, and if the spinning temperature exceeds 290°C, the physical properties of the conjugate fiber may decrease. Also, if the winding speed is less than 500m/min, there may be a problem that the physical properties of the composite fiber and/or the application product using the composite fiber will decrease due to the increase in elongation, and if the winding speed is greater than 1,300m/min, then There may be a problem in that drawing workability is lowered due to non-uniform stacking of undrawn sub-filament bundles on the tank.

Moreover, the above-mentioned divided filament bundles in step 2 may be sheath-core monofilaments, side-by-side monofilaments, island-in-the-sea monofilaments or split monofilaments.

The stretching in step 3 can be carried out by conventional stretching methods in the art, preferably, the unstretched sub-filament bundle can be stretched to 2.5 to 5 times at a temperature of 70 to 100°C, preferably Ground, 3.0~4.5 times. At this time, if the draw ratio is less than 2.5 times, the physical properties of the application product using the composite fiber will decrease due to the increase in elongation, and if the draw ratio exceeds 5.0 times, there may be a problem of broken filaments. Stretch within the range.

Moreover, the crimping in step 3 can be carried out by a conventional crimping method in the art. Preferably, as an example, a crimping box can be used to crimp through a crimp forming process. Pass 3,000~8,000de.

Moreover, before crimping, a step of increasing the stability of the divided filament bundles by performing a length-fixing heat treatment process on the stretched divided filament bundles may be further performed. To give a specific example, a plurality of hot drums can be used to heat the sub-filament bundles in contact with the surface of the hot drums for about 5-30 seconds, so as to increase the crystallinity of the sub-filament bundles, thereby increasing the shrinkage rate and elastic rate.

The heat fixing in step 4 can be carried out by conventional heat fixing methods in the art, preferably, as an example, after the stretched and crimped sub-filament bundles are put into the oven (oven), at 140 ~ 180 ° C temperature, preferably at a temperature of 140-170° C. for 10-20 minutes. At this time, if the heat-fixing temperature is less than 140°C, there may be a problem that the shrinkage of the final conjugated fiber produced may increase, and if the heat-fixing temperature exceeds 180°C, there may be a problem that the fiber aggregates may be recombined due to a decrease in the dispersion of the conjugated fibers. Since fiber density is lowered and workability is lowered, it is preferable to heat fix at a temperature within the above-mentioned range.

Moreover, the cutting in step 4 is a process of cutting the heat-fixed sub-filament bundles according to the processed product using the composite fiber so that the composite fiber has an appropriate fiber length, which can be performed by a conventional cutting method in the art, preferably, in the form of Cut the composite fiber so that the average fiber length is in the range of 3 to 120 mm.

Through the above preparation method, as described above, the composite fiber of the present invention having an average fineness of 4 to 12 de, an average fiber length of 3 to 120 mm, and a number of crimps of 9 to 15 per inch can be prepared.

A fiber aggregate such as a nonwoven fabric or the like can be produced by using the conjugate fiber of the present invention as described above. At this time, the above-mentioned fiber aggregate may be a dry-laid nonwoven fabric, a wet-laid nonwoven fabric or an air-laid nonwoven fabric, preferably, may be a nonwoven fabric such as a thermal bonding (thermal bonding), a needle Dry-laid nonwoven fabrics such as needle-punching nonwoven fabrics.

Also, a compression molded article can be produced by stacking the above-mentioned fiber aggregates in one or more layers, and then performing compression molding. The fiber aggregate layers are stacked or interposed, followed by compression molding to produce a compression molded article.

Hereinafter, the present invention will be described in more detail with reference to examples, however, the following examples should not be construed as limiting the scope of the present invention, but should be construed as facilitating understanding of the present invention.

[Example]

Example 1: Preparation of sheath-core composite fiber

A polyethylene terephthalate chip was prepared in which a polyethylene terephthalate resin having an intrinsic viscosity of 0.65 dl/g and a melting point of 252° C. was formed into a chip.

Then, a polypropylene chip was prepared in which a polypropylene resin having an enthalpy value of 94 J/g for melting crystals and a melting point of 165° C. in differential thermal analysis was used as a chip.

Next, melt the above-mentioned polyethylene terephthalate chip at 290°C, melt the polypropylene chip at 260°C, and then put the above two chips into a composite spinning nozzle for spinning and cooling to produce Sheath-core undrawn split tow.

At this time, after composite spinning was performed under the conditions of a spinning temperature of 275° C. and a winding speed of 950 m/min, it was loaded into a tank through a drawing step.

Next, after stretching the above-mentioned unstretched sub-filaments 3.2 times at 85°C, heat treatment for length fixation was performed at 150°C for 10 seconds.

Next, the stretched partial tow is crimped using a stuffing box.

Afterwards, put the stretched and crimped filament bundle into an oven, and heat-fix at 165°C for 15 minutes to prepare a sheath-core composite with an average fineness of 7de, an average fiber length of 51mm, and a crimp number of 11/inch. fiber. At this time, the cross-sectional area ratio of the sheath and the core is 1:1, wherein the sheath is made of polypropylene resin, and the core is made of polyethylene terephthalate resin.

Embodiment 2 ~ embodiment 12 and comparative example 1 ~ 10

In addition to changing the polyethylene terephthalate chip as the core component, the polypropylene chip as the sheath component, the average fineness, the average fiber length, the number of crimps, and the cutoff of the sheath and core as shown in Tables 1 and 2 below, Except for the area ratio, the remaining sheath-core composite fibers were prepared in the same manner as in Example 1 above to implement Examples 2-12 and Comparative Examples 1-10.

Experimental Example 1: Measurement of Physical Properties of Composite Fibers

The tenacity, elongation, initial modulus of elasticity, and shrinkage of the composite fibers of the sheath-core type composite fibers prepared in the above-mentioned Examples and Comparative Examples were measured based on the following methods, and the results are shown in Table 3 below.

1) Measurement method of tenacity and elongation

The tenacity and elongation of the fibers were measured using an automatic tensile testing machine (Textechno Corporation) at a speed of 50 cm/m and a gripping distance of 50 cm. The value (g/de) obtained by dividing the load required to stretch the fiber until it is cut by applying a predetermined force to the fiber is defined as the tenacity (g/de), expressed as a percentage relative to the initial length of the stretched length The value (%) is defined as elongation.

2) Measurement method of initial elastic modulus and shrinkage rate

The initial modulus of elasticity was measured by a USTER TESTER, and the length change of the composite fiber before and after dry heat treatment at 180° C. for 20 minutes was measured according to Mathematical Formula 1 below.

[Mathematical formula 1] Shrinkage rate (%)=(C-D)/C×100%

In Mathematical Formula 1, C is the average length of fibers before heat treatment, and D is the average length of fibers after heat treatment.

With reference to the physical performance results of the composite fibers shown in Table 3 above, in the case of Examples 1-12, the tenacity is 3.71-4.08g/d, the elongation is 57.3-61.7%, and the initial elastic modulus is 3.3-3.6g /d, the shrinkage rate is 5.5~6.0%, and the number of crimps is 9.3~13.5 per inch.

In contrast, in the case of Comparative Example 1 in which the melting point of the skin component was higher than 170°C, there was a problem that the initial elastic modulus was less than 3.2 g/d, that is, the initial elastic modulus was low. In the case of Example 2, there was a problem that the spinning was poor, so the physical properties of the conjugate fiber could not be measured.

Also, in the case of Comparative Example 3 in which polyethylene terephthalate having an intrinsic viscosity of more than 1.0 dl/g was used as the core component, the toughness and elongation were lowered compared with Examples.

Furthermore, in the case of Comparative Example 5 in which the cross-sectional area ratio of the sheath to the core of the conjugate fiber was 1:0.45, that is, less than 1:0.5, there was a problem that the elongation was very poor.

In addition, in the cases of Comparative Example 7 in which the average fineness of the conjugate fiber was larger than 12de and Comparative Example 8 in which the average fineness was less than 4de, spinning was not actually possible.

Moreover, in the case of Comparative Example 9 with the number of curls greater than 16/inch, there was a problem that the number of curls was greater than 15/inch, that is, the number of curls was too large, and in the case of Comparative Example 10 with the number of curls less than 9/inch , there is a problem that the number of curls is small.

Preparation Example 1: Preparation of Compression Molded Product

Carding was performed using only the conjugate fiber prepared in Example 1 to prepare a needle-punched nonwoven fabric having a thickness of 10 mm.

Next, after heat-treating the above-mentioned nonwoven fabric at 200° C. for 90 seconds, it was subjected to cold compression to prepare a compression molded product (average thickness: 3 mm).

The average areal density of the prepared compression molded article was 1,230 g/m ² , and the uniformity of the average areal density was 3CV%.

Preparation Example 2: Preparation of Compression Molded Product

50% by weight of the composite fiber prepared in Example 1 above and 50% by weight of 7 denier polyethylene terephthalate having a fiber length of 51 mm and an intrinsic viscosity of 0.65 dl/g were mixed and carded, To prepare a needle-punched nonwoven fabric with a thickness of 10 mm.

Next, a compression-molded product (average thickness: 3 mm) was prepared by performing a heat treatment process and cold compression in the same manner as in Preparation Example 1 above.

The average areal density of the prepared compression molded article was 1,250 g/m ² , and the uniformity of the average areal density was 4.6CV%.

Preparation Example 3: Preparation of Compression Molded Product

70% by weight of the composite fiber prepared in the above-mentioned Example 1 and 30% by weight of 7 denier fiber made of polyethylene terephthalate having an intrinsic viscosity of 0.65 dl/g and a fiber length of 51 mm After the staple fibers were mixed, carding was performed to prepare a needle-punched nonwoven fabric having a thickness of 10 mm.

Next, a heat treatment process and cold compression were performed by the same method as in Preparation Example 1 above to prepare a compression molded product (average thickness: 3 mm).

The average areal density of the prepared compression molded article was 1,210 g/m ² , and the uniformity of the average areal density was 3.8CV%.

Preparation Examples 4~14: Preparation of Compression Molded Products

A needle-punched nonwoven fabric having a thickness of 10 mm was prepared by the same method as in Example 1 above, except that the conjugate fibers of Examples 2 to 12 were used instead of the conjugate fibers of Example 1 for carding.

Next, after heat-treating the above-mentioned nonwoven fabric at 200° C. for 90 seconds, cold compression was performed to prepare a compression molded product (average thickness 3 mm), thereby carrying out preparation examples 4 to 14 respectively (refer to Table 4 below)

Comparative Preparation Example 1

After mixing 60% by weight of 9-denier monofilament polypropylene fibers having a fiber length of 70 mm and 40% by weight of glass fibers, carding was performed to prepare a needle-punched nonwoven fabric having a thickness of 10 mm.

Next, a compression-molded product (average thickness: 3 mm) was prepared by performing a heat treatment process and cold compression in the same manner as in Preparation Example 1 above.

Comparative Preparation Example 2

50% by weight of 4-denier polyethylene terephthalate binder fibers with a fiber length of 51mm and a softening point of 110°C and 50% by weight of fibers with a length of 51mm and an intrinsic viscosity of 0.65dl/g After the 7-denier short fibers made of polyethylene terephthalate were mixed, they were carded to prepare a needle-punched nonwoven fabric with a thickness of 10 mm.

Next, heat treatment process and Cold compression was used to prepare compression moldings (average thickness 3 mm).

Comparative Preparation Examples 3~9: Preparation of Compression Molded Articles

A needle-punched nonwoven fabric having a thickness of 10 mm was prepared by the same method as in Example 1 above, except that the conjugate fibers of Comparative Examples 1 to 10 were used instead of the conjugate fibers of Example 1 for carding.

Next, after heat-treating the above-mentioned nonwoven fabric at 200° C. for 90 seconds, cold compression was performed to prepare a compression molded product (average thickness 3 mm), thereby performing Comparative Preparation Examples 3 to 9, respectively (refer to Table 4 below).

Experimental example 1: SEM measurement of compression molded product

The SEM photographs of the cut sections of the compression molded articles prepared in Preparation Example 1, Preparation Example 2, and Preparation Example 3 are shown in Fig. 1 to Fig. 3 in order, respectively.

As shown in the SEM measurement photograph of FIG. 1, in the case of the compression molded article of the present invention, the fibers are densely formed, on the contrary, in the case of Preparation Example 2 and Preparation Example 3, as shown in FIGS. 2 and 3 , the fiber formation density is lower than that of Preparation Example 1.

Experimental Example 2: Measurement of Form Stability of Compression Molded Articles

1) Form stability according to temperature

After putting the compression-molded articles prepared in the above-mentioned Preparation Example 1, Comparative Preparation Example 1, and Comparative Preparation Example 2 into a hot-air dryer, aging for 1 hour under a load of 80 g was applied, and then the morphology change was confirmed. The results are shown in Fig. 4 .

Referring to FIG. 4 , it can be confirmed that in the case of the compression-molded product of Preparation Example 1, the morphological stability is also good at 100°C and 110°C. On the contrary, in the case of comparative Preparation Examples 1 and 2, the morphological stability Decrease from 100°C.

2) Measurement of morphological stability after aging in a heat-resistant environment

After placing the compression-molded articles prepared in the above-mentioned Preparation Example 1, Comparative Preparation Example 1, and Comparative Preparation Example 2 in a heat-resistant environment, the external force was removed, and then the morphological stability after 72 hours at 80° C. was measured. The results are shown in Figure 5.

Referring to FIG. 5 , in the case of Preparation Example 1, there seemed to be no morphological change, but in the case of Comparative Preparation Example 1, it was greatly bent, and Comparative Preparation Example 2 also showed a tendency to slightly warp at the end.

It was confirmed by measuring the morphological stability that the compression-molded article made of the conjugate fiber of the present invention is very excellent in morphological stability.

Experimental Example 3: Measurement of Tensile Strength and Modulus of Compression Molded Articles

The tensile strength, flexural strength, and flexural modulus of the compression molded articles prepared in Preparation Examples 1 to 14 and Comparative Preparation Examples 1 to 12 were measured, and the results are shown in Table 5 below.

At this time, tensile strength was measured based on ASTM D 638, and flexural strength and flexural modulus as modulus were measured based on ASTM D 790.

Referring to the above Table 5, it can be confirmed that the tensile strength and modulus of the compression molded products of Preparation Examples 1 to 14 are generally better than those of Comparative Preparation Examples 1 to 2, and that the mixed use of polyethylene terephthalate Compared with Preparation Examples 2 to 3 of ester fibers, Preparation Example 1 using fibers for compression-molded articles alone exhibited relatively superior mechanical properties.

Also, in the case of Comparative Preparation Example 3, there was a problem that the bending strength was slightly low and the workability was low. Also, in the case of Comparative Preparation Example 4, the flexural modulus was inferior.

In addition, in the case of comparative preparation example 5, the flexural strength was excellent, but the tensile strength was slightly low, and in the cases of comparative preparation example 6 and comparative preparation example 7, there was a problem that the flexural strength and flexural modulus were too low.

Also, in the case of Comparative Preparation Example 8, there was a problem that neps occurred because the conjugate fiber used had a large number of crimps. In the case of Comparative Preparation Example 9, the bending elastic modulus was low because the number of crimps of the conjugate fiber used was too small.

From the above examples and experimental examples, it can be confirmed that the conjugate fiber of the present invention has excellent mechanical properties, sound absorption, sound dispersion, moisture absorption, and water dispersibility at the same time. It can be expected to provide various application products by forming the above-mentioned conjugate fiber of the present invention into a fiber aggregate such as a nonwoven fabric or compressing the above-mentioned fiber aggregate. As a specific example, the conjugate fiber of the present invention can be applied to construction Internal and external materials of objects, civil engineering materials, internal and external materials of transport units such as aircraft and ships, such as diapers, sanitary napkins and masks, etc. Sanitary materials and filters such as air filters and liquid filters, etc.

Claims (9)

A composite fiber for compression molding, characterized in that the composite fiber is a sheath-core composite fiber comprising a first component resin and a second component resin, wherein the intrinsic viscosity of the first component resin is 0.50 ~1.00dl/g and the melting point is 240~280°C, the melting point of the above-mentioned second component resin is 150~170°C, in the above-mentioned sheath-core composite fiber, the core composed of the above-mentioned first component resin and the above-mentioned first component resin The cross-sectional area ratio of the skin composed of the two-component resin is 1:0.5~1, the above-mentioned first component resin includes polyester resin, and the above-mentioned polyester resin includes polyethylene terephthalate resin, polyethylene terephthalate resin One or more of butylene dicarboxylate resin, polytrimethylene terephthalate resin, and polyethylene naphthalate resin, the above-mentioned second component resin includes polyolefin resin with a melting point of 150-170°C, and the above-mentioned The polyolefin resin includes at least one selected from polypropylene resin and polyethylene resin, and the temperature difference between the melting point of the first component resin and the second component resin is 30-100°C. The composite fiber for compression molding according to claim 1, wherein the enthalpy required for dissolving crystals of the above-mentioned crystalline polyolefin resin is 40 to 120 J/g in differential thermal analysis. The composite fiber for compression molded articles as described in item 1 of the scope of the patent application is characterized in that the above-mentioned polyethylene terephthalate resin comprises polymerized terephthalic acid and Polymers made of diols. The composite fiber for compression molding as described in any one of items 1 to 3 of the scope of application is characterized in that the average fineness of the fibers used for compression molding is 4~12de, and the average fiber length is 3~12. 120mm, the number of crimps is 9~15 per inch. A method for preparing a composite fiber for a compression molded product, comprising: step 1, separately preparing a polyester chip and a crystalline polyolefin chip; step 2, melting the polyester chip and a crystalline polyolefin chip respectively Put the first component resin and the second component resin into the composite spinning nozzle for composite spinning, and then prepare the undrawn sub-filament bundle by cooling; step 3, stretch the above-mentioned undrawn sub-filament bundle , then give crimp; and step 4, heat fixing and cutting the stretched and crimped sub-filament bundle, wherein, the above-mentioned sub-filament bundle is a sheath-core monofilament, and in step 2, the melting of the polyester chip is carried out at 270 It is carried out at a temperature of ~300°C, and the melting of the crystalline polyolefin core is carried out at a temperature of 230~280°C. The above-mentioned first component resin constitutes the core, the above-mentioned second component resin constitutes the skin, and the above-mentioned first component resin constitutes the skin. Intrinsic viscosity is 0.50~1.00dl/g and melting point is 240~280°C, the above-mentioned first component resin includes polyester resin, and the above-mentioned polyester resin includes polyethylene terephthalate resin, polyethylene terephthalate resin One or more of butylene formate resin, polytrimethylene terephthalate resin and polyethylene naphthalate resin, the melting point of the above-mentioned second component resin is 150~170°C, the above-mentioned second component resin Polyolefin resins are included, and the polyolefin resins include one or more selected from polypropylene resins and polyethylene. The method for preparing composite fibers for compression moldings as described in item 5 of the scope of patent application is characterized in that, in step 2, the composite spinning is carried out at a spinning temperature of 260~290°C and a winding speed of 400~ 1,300m/min conditions. A fiber aggregate for compression molding, characterized in that it includes the composite fiber as described in item 4 of the patent application. A non-woven fabric for compression molding, characterized in that it includes the fiber aggregate as described in item 7 of the scope of application. The non-woven fabric for compression molding as described in item 8 of the scope of the patent application is characterized in that the non-woven fabric is a dry-laid non-woven fabric, a wet-laid non-woven fabric or an air-laid non-woven fabric.

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