KR101417193B1 - Recycled polyester polymer and Method for manufacturing the same, Spun bond nonwoven fabric using the same - Google Patents

Abstract

The present invention relates to a recycled polyester polymer having a high viscosity, no discoloration and excellent physical properties by regulating the residual moisture content to an optimum state and adding chain extender and a polymerization catalyst in an optimum amount in regenerating a waste polyester product, To a spunbonded nonwoven fabric. The recycled polyester polymer of the present invention contains a residual moisture content of 0.1% by weight or less.

Description

[0001] The present invention relates to a recycled polyester polymer and a spun bond nonwoven fabric using the same,

The present invention relates to a recycled polyester polymer, a process for producing the recycled polyester polymer, and a spunbonded nonwoven fabric produced using the recycled polyester polymer. More specifically, the present invention relates to a recycled polyester polymer using a recovered waste polyester product, To a spunbond nonwoven fabric.

Polyesters made from fossil fuels are used in a variety of food containers and such polyester products are turned into a vast amount of waste after use. These waste polyester products have a problem of polluting the environment when disposed of.

To solve these problems, we have recycled waste polyester products. These recycling methods include chemical recycling, material recycling, and thermal recycling.

However, the chemical recycle can be used as a raw material for producing various chemical products by chemically decomposing a waste polyester product, and it is possible to obtain a high quality product, but a technical approach is difficult and a processing cost is high. In addition, thermal recycling is a method of carbonizing a waste polyester product to utilize heat energy generated from the waste. In this case, harmful compounds such as dioxins are produced at the time of incineration, thereby polluting the environment.

In order to solve these problems, interest in material recycling has been greatly increased. However, there is a problem that the polymer produced therefrom has low viscosity and color and physical properties are deteriorated as acid terminal groups are increased.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method for regenerating a waste polyester product in which the residual water content is adjusted to an optimum state, It is an object of the present invention to provide such an excellent recycled polyester polymer and a spunbonded nonwoven fabric using the same.

In order to solve the above object, the present invention provides a recycled polyester polymer containing a residual water content of 0.1% by weight or less.

In another aspect, the present invention provides a regenerated spunbonded nonwoven fabric comprising at least 10% by weight of the recycled polyester polymer.

In another aspect, the present invention relates to a process for producing a flake by pulverizing a waste polyester product; Drying the flakes such that the residual moisture percentage is not more than 0.1% by weight; And melting the dried flakes to prepare a regenerated polyester melt. The present invention also provides a method for producing a recycled polyester polymer.

The present invention has the following effects.

The regenerated polyester polymer according to the present invention can minimize the viscosity drop by controlling the residual water content to a certain level or less and adding the chain extender and the polymerization catalyst to the optimum range.

The recycled polyester polymer according to the present invention has a low acid end group and can prevent discoloration.

The recycled polyester polymer having such properties is excellent in moldability and thus can be utilized in the production of spunbonded nonwoven fabrics and the like.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Therefore, the present invention encompasses all changes and modifications that come within the scope of the invention as defined in the appended claims and equivalents thereof.

Hereinafter, a recycled polyester polymer according to an embodiment of the present invention, a method for producing the same, and a spunbonded nonwoven fabric produced using the same will be described in detail.

First, the recycled polyester polymer contains a residual water content of 0.1% by weight or less.

In order to recycle the waste polyester product, it is important to lower the residual moisture content of the waste polyester to a predetermined range or less. When molten polyester having a high residual water content is melted and extruded or molded, viscosity decreases and color changes due to moisture.

Therefore, if the residual moisture content of the recycled polyester polymer is more than 0.1% by weight, the viscosity drops sharply due to moisture and the acid terminal group rapidly increases, so that the extrusion or molding processability is poor and the color can easily change.

The recycled polyester polymer may comprise a chain extender. The waste polyester may be used for a long time, resulting in lowering the melt viscosity as the molecular weight is lowered, so that the extrusion or molding processability may be deteriorated.

Thus, to ensure a smooth extrusion or molding process, the recycled polyester polymer may comprise from 0.0005 to 2.0 wt.% Of a chain extender, preferably from 0.01 to 1.5 wt.% Of a chain extender. If the content of the chain extender is less than 0.0005% by weight, the esterification reaction and the polycondensation reaction are not sufficiently carried out, so that the viscosity decrease can not be smoothly prevented. On the other hand, when the content of the chain extender exceeds 2.0% As the esterification reaction proceeds, the inner pressure of the extruder sharply increases during the molding process, and thus the processability may be lowered due to overloading.

The chain extender may include glycidyl methacrylate. As the glycidyl methacrylate easily reacts with the ester compound, the viscosity of the regenerated polyester can be easily produced within a level required for ensuring smooth processability.

The recycled polyester polymer may include at least one of a tin-based catalyst and a titanium-based catalyst.

The tin catalyst may comprise an inorganic tin compound or an organic tin compound. The inorganic tin compound may be in the oxide form, for example, bismuth trioxide (Sn ₂ O ₃ ).

The titanium-based catalyst may include an inorganic titanium compound or an organic titanium compound. The inorganic titanium compound may be an oxide form, such as titanium dioxide (TiO _2). The organic titanium compound may be a tetraalkyl titanate compound which is easy to obtain and has excellent effect.

The content of the catalyst may be 10,000 ppm or less, preferably 6,000 ppm or less.

The recycled polyester polymer may contain up to 300 ppm of phosphoric acid (H ₃ PO ₄ ). Such phosphoric acid can serve to prevent the recycled polyester polymer from being oxidized by heat upon melting.

The recycled polyester polymer is not limited to polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate and the like.

The recycled polyester polymer can be produced by using waste polyester products such as garments, carpets, ornaments, bottles, and wrapping paper.

As described above, the recycled polyester polymer having an optimum combination of low residual moisture content, chain extender, antioxidant, polymerization catalyst and the like has an intrinsic viscosity of 0.60 to 0.75 dl / g, a melt viscosity of 1,000 to 1,800 poise, And a recycled polyethylene terephthalate polymer having a content of 25 eq / ton.

The recycled polyethylene terephthalate polymer has an excellent range of intrinsic viscosity and melt viscosity, and therefore has excellent moldability, and discoloration is not easy due to low content of acid end groups.

Next, a regenerated spunbonded nonwoven fabric according to an embodiment of the present invention will be described in detail.

The reclaimed spunbond nonwoven fabric comprises a recycled polyester polymer.

The reclaimed spunbond nonwovens may comprise less than 10% by weight of recycled polyester polymer, and preferably 30 to 100% by weight of recycled polyester polymer. The recycled spunbond nonwoven may be less economical if it contains less than 10% by weight of recycled polyester polymer.

Next, a method for producing a recycled polyester polymer according to an embodiment of the present invention will be described.

First, the waste polyester product is pulverized to produce a flake. The waste polyester product may be a PET bottle widely used as a beverage bottle. The flake production process can be carried out using a conventional mill. For smooth drying, the flakes may have a size of 1 to 5 mm.

Then, the flakes are dried so that the residual water content is 0.1 wt% or less.

The flake drying process may be performed at a temperature of 60 to 200 DEG C, preferably 100 to 150 DEG C in a nitrogen gas atmosphere using a vacuum drier. If the drying temperature is lower than 60 ° C, it may take a long time of 24 hours or longer to obtain a flake having a required level of residual moisture, The drying may not be performed smoothly due to the occurrence of lumping phenomenon in which flakes are elongated due to elution of short-chain or oligomer.

The flake drying process may be performed for 1 to 24 hours. If the drying time is less than 1 hour, a flake having a required level of residual moisture content can not be obtained. On the other hand, if the drying time exceeds 24 hours, the physical properties may be deteriorated as the molecular chain of flake is thermally decomposed.

The flake drying process may be sealed with nitrogen gas to prevent moisture from entering the flakes after drying.

Then, the dried flakes are used to prepare a recycled polyester melt. The reclaimed polyester melt contains a chain extender. More specifically, the dried flakes are fed into an extruder provided with a side feeder, and a chain extender in the form of a master batch is fed through a side feeder to feed the regenerated polyester melt in an amount of 0.0005 to 2.0 wt% 0.01 to 1.5% by weight of a chain extender. As the chain extender, glycidyl methacrylate can be used. By adding such a chain extender, it is possible to prevent viscosity decrease during melting.

The reclaimed polyester melt manufacturing process using the extruder can be carried out at 80 to 120 RPM, preferably at 100 to 110 RPM. If the RPM of the extruder is less than 80, the dried flakes stay in the extruder for a long time, so that they may be discolored due to deterioration, the viscosity may be rapidly lowered, the productivity may be lowered, and the economical efficiency may be lowered. On the other hand, when the extruder has an RPM of more than 120, the chain extender and the polyester molecule do not react sufficiently, so that the molecular weight distribution can be widened and the viscosity variation can be increased.

The reclaimed polyester melt manufacturing process may include a step of adding a condensation polymerization catalyst. The addition amount of the catalyst can be appropriately adjusted so that the catalyst content of the recycled polyester melt is 10,000 ppm, preferably 6,000 ppm or less.

The step of producing the reclaimed polyester melt may include a step of adding 300 ppm or less of a thermal oxidation inhibitor in order to prevent the polyester from being oxidized due to heat. As the thermal oxidation inhibitor, phosphoric acid or the like can be used.

Subsequently, the recycled polyester melt can be used for extrusion or molding. Specifically, the recycled polyester melt can be used to produce recycled chips by extrusion, and such recycled chips can be mixed with other virgin polyester chips to produce a variety of products such as spunbond nonwovens. The recycled polyester melt can also be used to produce recycled products such as spunbonded nonwovens through spinnerets and the like directly connected to extruders.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. It should be noted, however, that the following examples are intended to assist the understanding of the present invention, and the scope of the present invention should not be limited thereby.

Example  One

The waste PET bottle from which the foreign substance was removed was cut into a size of about 2 mm to prepare a flake. The flakes had an intrinsic viscosity of 0.813 dl / g, a melt viscosity of 1,944 poise, an acid end group content of 25 eq / ton, and a residual moisture content of 0.52 wt%.

Then, the flakes were placed in a vacuum drier and dried at a temperature of 130 ° C. for 8 hours so that the residual moisture content of the dried flakes was 0.05 wt%, and the flakes were stored in a nitrogen gas atmosphere of 1.0 to 1.5 kgf / cm 2 .

Subsequently, the dried flakes were put into an extruder in the form of a vent screw maintained at 290 ° C, melted and extruded to prepare a recycled PET chip.

Example  2

Except that in Example 1 described above, a master chip containing glycidyl methacrylate as a chain extender was fed through a side feeder of the extruder and melted together to include a chain extender in an amount of 0.2 wt% , A regenerated PET chip was produced in the same manner as in Example 1. [

Comparative Example  One

In the above-described Example 1, a regenerated PET chip was produced by the same method as in Example 1, except that the flakes were not dried.

Comparative Example  2

In the above-described Example 1, a regenerated PET chip was produced in the same manner as in Example 1, except that the flakes were not dried so that the residual water content of the flakes was 0.2 wt%.

The residual moisture content, intrinsic viscosity, melt viscosity, acid end group content and filament tensile strength of the recycled PET chips obtained by the above Examples and Comparative Examples were determined by the following methods, and the results are shown in Table 1.

Remaining water content (%)

The residual moisture percentage (%) was calculated by the following equation using a conventional evaluation method by 768 KF-OVEN.

Water content = (S-B) / (W x 1,000) x 100

S: Water sample,, B: Water sample,, W: Amount of sample (㎎)

Intrinsic viscosity (dl / g)

The intrinsic viscosity was evaluated using a conventional ASTM D 4603 method. In detail, the solid samples were dissolved in solvents at different concentrations, and the viscosity was measured at a constant temperature using a Ubbelohde viscometer (Capillary Viscometer) The intrinsic viscosity is calculated by extrapolation.

Intrinsic Viscosity = (0.0242 x? _R + 0.2634) x F

η _r : Relative viscosity

F: (IV of standard Chip (A)) / (10 average values measured with A)

Melt viscosity ( poise )

Melt Viscosity was measured at 285 ° C using Rheo-Tester 2000 equipment according to ASTM D3835 method.

mountain Horse short  content( eq / tons )

The acid end group content was evaluated in accordance with the conventional ASTM D 1926 method and was calculated in detail by the following equation.

-COOH = {(a-b) x 40 x f / A

a: the amount of sample solution to be consumed (ml), b:

A: Sample amount (g), f: Factor of N / 25-NaOH alcohol solution

Filament tensile strength (g / d)

The virgin chips were mixed and melted at 50 wt% in the regenerated PET chips produced by the above-described Examples and Comparative Examples, and then spun through spinnerets to obtain regenerated filaments.

The strength and elongation of each of the regenerated filaments thus obtained were measured using an Instron 5565 according to KS K 0412.

Radioactive

Using a polyester long fiber spunbond facility, it was operated for 120 hours to measure the radioactivity at a yield rate of 9.2 tons.

division Chain extender content (wt%) Remaining water content (%) Intrinsic viscosity (dl / g) The melt viscosity (poise) Acid short term content (eq / ton) Filament tensile strength (g / d) Radioactive Example 1 0 0.05 0.643 1,010 41 4.2 91 Example 2 0.2 0.05 0.701 1,699 12 4.7 96 Comparative Example 1 0 0.52 0.562 337 56 3.2 64 Comparative Example 2 0 0.2 0.603 808 49 3.6 77

Claims (14)

delete delete delete delete delete delete delete Pulverizing a waste polyester product to produce a flake;
Drying the flakes such that the residual moisture percentage is not more than 0.1% by weight; And
And melting the dried flakes to prepare a regenerated polyester melt,
Wherein the step of drying the flakes is carried out at a temperature of 60 to 200 DEG C and for 1 to 24 hours. delete Pulverizing the waste polyester product to produce a flake;
Drying the flakes such that the residual moisture percentage is not more than 0.1% by weight; And
And melting the dried flakes to prepare a regenerated polyester melt,
Wherein the step of drying the flakes includes a step of storing the dried flakes in a nitrogen gas state. 9. The method of claim 8,
Wherein the step of producing the recycled polyester melt comprises adding tin-based and titanium-based catalysts of 10,000 ppm or less. 9. The method of claim 8,
Wherein the step of producing the recycled polyester melt comprises a step of not more than 1.0 wt% of a chain extender. Pulverizing the waste polyester product to produce a flake;
Drying the flakes such that the residual moisture percentage is not more than 0.1% by weight; And
And melting the dried flakes to prepare a regenerated polyester melt,
Wherein the step of producing the recycled polyester melt is performed in an extruder which maintains a rotation number of 80 to 120 rpm. 9. The method of claim 8,
Further comprising a step of extruding or molding using the recycled polyester melt.