KR20040011207A - Thermally bondable polyterephthalate/polyethylene composite fiber with high interfacial adhesive strength - Google Patents

Abstract

PURPOSE: Polyethylene terephthalate / polyethylene type thermofusing conjugate fiber has excellent interface adhesive force, thermofusing property and carding property. A manufacturing method of the fiber is characterized by mixing a little material capable of dissolving polymers of the fiber on spinning. CONSTITUTION: The material is polyester / polyethylene block copolymer. Number average molecular weight of the polyethylene block is 2000-50000. Addition quantity of the material is 1-5pts.wt. based on the polyethylene terephthalate.

Description

Thermally bondable polyterephthalate / polyethylene composite fiber with high interfacial adhesive strength}

The present invention relates to a heat sealable composite fiber, and more particularly, to a polyethylene terephthalate / polyethylene heat sealable composite fiber having excellent interfacial adhesion between the polymers to be composited and excellent shape stability.

Until now, as a heat-sealed fiber, a web made through a composite spinning of two kinds of polymers, that is, polyester / polyester, polyester / polyolefin and polyolefin / polyolefin into a sheath-core type, followed by stretching and nonwoven fabric processes Patents are known in which a form is heat-treated at a predetermined temperature to bond fibers together (see Japanese Patent Application Laid-Open No. 54-44773).

In the case of sheath type heat-sealed fiber composed of polyester / polyester, the outer part corresponding to sheath is usually made of co-polyester, and the latent crystals in amorphous resins are changed by varying the copolymer composition ratio according to the heat-sealing temperature. Various types of resins can be prepared, including resins and crystalline resins.

In the case of the core sheath type heat-sealed fiber composed of polyester / polyolefin, the core component is usually polyester and the super component is mainly polyolefin such as polyethylene or polypropylene. The heat melting temperature is near the melting temperature of the polyolefin. It can be said.

In addition, heat-sealing fibers, in which both core and supercomponents are made of polyolefin / polyolefin, have been developed for cost reduction. The core component is polypropylene and the supercomponent is polyethylene.

However, conventional polyester / polyolefin-based and polyolefin / polyolefin-based heart sheath fibers have a disadvantage in that they do not have good compatibility unlike polyester / polyester sheath-type fibers and thus have poor adhesion between interfaces.

Adhesion between interfaces has a significant effect on fiber quality in the process of applying tensile and shear tension such as spinning process and stretching process. For example, when interfacial adhesion between ponchos is not good, Slip may occur and single yarn phenomenon may occur, and in the stretching process, core and supercomponents may be respectively stretched to cause peeling between interfaces. In this case, the phenomena of the super ingredient may stick out and the adhesion may not occur at a predetermined heat melting temperature. In addition, the adhesion between these interfaces is poor may lead to a decrease in physical properties such as mechanical strength of the fiber.

In an attempt to improve the adhesion between the interfaces in heat-sealed fibers using two kinds of polymers of poor compatibility, a technique in which a polyolefin is surface treated with a carboxyl group, a hydroxyl group, or a glycidyl group having a polar group to induce a reaction with a polyester. (JP-A 9-170116, Japanese Patent Application Laid-Open No. 61-201025) have been proposed, but in some cases, especially in the case of graft copolymerization by plasma, the polymer chain may be broken by plasma treatment to reduce the strength. Induced by the stretching process and the carding process is a problem that causes the cutting of the polyolefin.

The technical problem is to provide a high-quality heat-sealed fiber by preventing a decrease in fairness and mechanical properties due to poor adhesion between polymer interfaces of the heat-sealed composite fiber made of poorly compatible polymers.

In order to solve the above problems, the present inventors have conducted extensive research, and found that two-component polymers having poor compatibility with each component polymer were made into random, block, or graft copolymers. The present invention has been completed by discovering that a small amount of mixed and spun in the process can produce a deep sheath type fiber having excellent interfacial adhesion between two component polymers.

Therefore, according to the present invention, in a polyethylene terephthalate / polyethylene-based heat sealable composite fiber having a compatibilizer interposed at an interface, the compatibilizer is characterized by a polyester / polyethylene block copolymer having a number average molecular weight of 2,000 to 50,000. Provided is a heat sealable composite fiber.

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

The present invention relates to improving interfacial adhesion by using a compatibilizer of two polymers in a heat-adhesive composite fiber of polyethylene terephthalate and polyethylene having low compatibility.

As the composite fiber of the present invention, a polyester / polyethylene block copolymer is used in which a polymer having a similar solubility parameter and a polymer having a similar solubility parameter is copolymerized.

The polyester / polyethylene block copolymer used as a compatibilizer varies depending on the molecular weight of the blocked component polymer, and in the case of the polyethylene terephthalate / polyolefin-based heat sealable composite fiber of the present invention, the polyester / Polyethylene block copolymers are most compatible with block copolymers having a molecular weight similar to that of the polymer to be composited. Particularly preferred polyester / polyethylene block copolymers are those having a number average molecular weight of 2,000-50,000 of polyethylene blocks. Here, when the number average molecular weight of the polyethylene block is less than 2,000, the melt viscosity is almost low in the form of wax, so that the interfacial adhesion is low due to the less effective effect of the compatibilizer upon mixing, and the compatibilizer itself when the number average molecular weight of the polyethylene block exceeds 50,000. Another interface is formed in the surface, and thus the interfacial adhesion is lowered.

The content of the compatibilizer in the polyethylene terephthalate / polyolefin-based heat sealable composite fiber of the present invention is 1-5 parts by weight relative to the polyethylene terephthalate constituting the composite fiber when the compatibilizer is a polyester / polyethylene block copolymer alone. Here, when the added amount is less than 1 part by weight, the effect of the compatibilizer is small and the interfacial adhesive force is lowered. When the added amount is more than 5 parts by weight, another interface is formed in the compatibilizer itself, and the interfacial adhesive force is lowered.

Features and other advantages of the present invention as described above will become more apparent from the examples and comparative examples described below. However, the present invention is not limited to the following examples.

Properties shown in the following Examples and Comparative Examples are measured by the following method.

* Interfacial Adhesion: A bundle of samples were fixed with epoxy resin, microtomized with a sharp knife, surface coated with gold foil, and scanning electron microscopy was performed to observe the peeling phenomenon at the interface. Scanning electron microscopy (SEM) When sectional observation, the interface peeling degree was divided into 10 grades, and the higher the grade, the better the interface bonding state.

* Heat sealability: After melting for 3 minutes at 150 ℃, the degree of fusion is divided into 10 grades. The higher the grade, the better the heat sealability.

* Carding property: In the process for making nonwoven web, the peeling degree of the sheath component after passing the carding machine is divided into 10 grades, and the higher the grade, the better the carding ability.

<Example 1>

The core and supercomponents each have an area ratio of 50 to 50 and use a circular nozzle having a circular border of the core (0.3 mm hole, 1800 holes radially arranged), and the core component has an intrinsic viscosity of 0.63 dl / g. Polyethylene terephthalate and a polyester / polyethylene block copolymer (PET) having a melt index of 18, a density of 0.960, and a molecular weight distribution index of 5 as polyethylene, and a compatibilizer as the number average molecular weight of the polyethylene block of 2000 -b-PE) is added to the core component spinning nozzle by adding 5 parts by weight of the core component polyester, and the poly-component spinning nozzle contains polyethylene having a melt index of 18. The spinning speed is 1000 m / min at a spinning temperature of 290 ° C. , After spinning with a flow rate of 4kg, stretched with an oil ratio of 3.5, a hydrophilic emulsion at a first stretching temperature of 75 ℃, a second stretching temperature of 80 ℃, after the crimping process 1 After cutting to make the fineness of 1.4de and the fiber length to 51mm by 2-15 degree, make a web of 50mm thickness in the carding process and put it on the mesh conveyor belt moving at the speed of 4m / min. Hot air was added so that the temperature might be 150 ° C.

<Example 2>

The same procedure as in Example 1 was repeated except that the number average molecular weight of the polyethylene blocks in the polyester / polyethylene block copolymer as the compatibilizer was 20,000.

<Example 3>

The same procedure as in Example 1 was repeated except that the number average molecular weight of the polyethylene blocks in the polyester / polyethylene block copolymer as the compatibilizer was 50,000.

<Example 4>

The same procedure as in Example 1 was repeated except that the addition amount of the compatibilizer polyester / polyethylene copolymer was changed to 3 parts by weight relative to the core component.

<Example 5>

The same procedure as in Example 1 was repeated except that the addition amount of the compatibilizer polyester / polyethylene copolymer was changed to 1 part by weight relative to the core component.

<Comparative Example 1>

The same procedure as in Example 1 was repeated without using a compatibilizer.

<Comparative Example 2>

The same procedure as in Example 1 was repeated except that the number average molecular weight of the polyethylene blocks in the polyester / polyethylene block copolymer as the compatibilizer was 70,000.

<Comparative Example 3>

The same procedure as in Example 1 was repeated except that the amount of the compatibilizer polyester / polyethylene copolymer was changed to 10 parts by weight relative to the core component.

The interfacial peelability, heat sealability and carding properties of the core component and the sheath component of the composite fiber obtained according to the above Examples and Comparative Examples were measured. The results are shown in Table 1.

division Compatibilizer (PET-b-PE) Interfacial Peelability Heat melting Carding PE block molecular weight Added amount (part by weight of core component) Example One 2000 5 10 10 10 2 20000 5 6 6 6 3 50000 5 5 5 5 4 2000 3 8 8 8 5 2000 One 6 6 6 Comparative example One - - One 2 One 2 70000 5 4 4 4 3 2000 10 3 3 3

As will be apparent from the results of Table 1 above, when the compatibilizer is interposed between two polymers having low compatibility, the interfacial adhesive force is very high, and the thermal bonding and carding properties are high quality. It is possible to produce a sex composite fiber.

Claims (2)

A polyethylene terephthalate / polyethylene based heat sealable composite fiber having a compatibilizer interposed at an interface, wherein the compatibilizer is a polyethylene terephthalate / polyethylene characterized by a polyester / polyethylene block copolymer having a number average molecular weight of 2,000-50,000. Heat-sealing composite fiber. The polyethylene terephthalate / polyethylene-based heat-sealing composite fiber according to claim 1, wherein the compatibilizer is polyester / polyethylene block copolymer and the addition amount is 1-5 parts by weight based on the combined polyethylene terephthalate.