KR20030037605A - Copolyester Polymer and process for preparing of it - Google Patents

Abstract

PURPOSE: Provided are a copolyester having similar physical property as a copolymer produced from typical monomers, wherein the copolyester is produced by depolymerizing a product and copolymerizing the depolymerized product with monomers for other polyester, and a method for producing the same. CONSTITUTION: The copolyester represented by formula 1 is produced by using polytrimethylene terephthalate waste, and has a limiting viscosity of 0.5 dl/g or more, a melting temperature of 255 deg.C or less, a terminal carboxyl group value of 50 meq/Kg KOH or less, and contents of dihydroxypropyl ether, dihydroxyethyl ether, and tetrahydrofuran which are byproducts, of 4 wt% or less, 4 wt% or less, and 6 wt% or less respectively. In the formula 1, a is an integer of 2-6, m+n is 100, 0<=m<=n, and each of m and n is a mole fraction.

Description

Copolyester polymer and its manufacturing method {Copolyester Polymer and process for preparing of it}

The present invention relates to a copolyester polymer of the general formula (1) prepared from polytrimethylene terephthalate (PTT) waste and a method for producing the same.

However, a is an integer of 2-6, m + n is 100, 0 <= m <= n100, and m and n represent each mole fraction.

In general, polyester has excellent mechanical properties and chemical properties such as chemical resistance is widely used in fibers, films and engineering plastics.

However, with the growing interest in the environment, research on its recycling is increasing.

Polyester is regenerated into monomers and oligomers thereof by chemical depolymerization.

Among them, PTT is depolymerized by terephthalic acid (abbreviated as TPA) or dimethyl terephthalate (abbreviated as DMT) and 1,3-propanediol (abbreviated as PDO), And bishydroxypropyl terephthalate (Bis (hydroxy 1,3-propyl terephthalate), hereinafter abbreviated as BHPT) and their low polymerization oligomers.

In PCT patent WO 01/19764, PTT polymers are prepared by polymerization using such regenerated monomers.

However, this method is only possible for the preparation of PTT homopolymers.

And since PTT has been industrialized for a while, little is known about its regeneration or degradation.

General polyester including PTT is widely used in fibers, films and engineering plastics, but has a high melting temperature and high processing temperature.

Therefore, studies are being conducted in parallel to improve the processability by copolymerizing a third copolymerization monomer to lower the melting temperature.

It is an object of the present invention to provide a copolyester polymer of formula (1) having the same physical properties as copolyesters prepared from general polymerization monomers by depolymerizing PTT products and then copolymerizing them with other polyester polymerization monomers. .

Another object is to provide a method for preparing the copolyester of the formula (1) having a unique physical property by adjusting the depolymerization reaction conditions and the composition of the copolymerized monomer to be added.

Copolyester polymer of formula (1) according to the present invention has a difference in physical properties depending on the use, but the ultimate viscosity (Intrinsic Viscosity, hereinafter abbreviated as IV) 0.5dl / g or more, Melting Temperature (abbreviated as Tm) 255 ℃ or less, Carboxyl End Group (hereinafter abbreviated as CEG) value is 50 meq / Kg KOH or below, Dihydroxyy propyl ether (hereinafter abbreviated as DPE) resulting from other reaction products, Dihydroxyethyl The content of ether (Dihydroxyethyl ether, hereinafter abbreviated as DEG) and tetrahydrofuran (abbreviated as THF) is 4 wt% or less of DPE, 4 wt% or less of DEG, and 6 wt% or less of THF.

However, a is an integer of 2-6, m + n is 100, 0 <= m <= n100, and m and n represent each mole fraction.

The PTT raw material to be provided for depolymerization in the present invention includes all products made of PTT fibers such as PTT polymers, fibers, clothing, carpets, bottles made of PTT polymers, films, and the like.

It is preferable to use these products by crushing them to a suitable size before depolymerization.

Since the PTT polymer itself is in the form of a chip, it may be used as it is, or fibers and the like may be used after being crushed to a length of about 10 cm or less.

In addition, defective products generated during PTT polymerization or spinning can be regenerated by this method.

The purpose of crushing the raw materials to a suitable size is to increase the surface area of these raw materials to facilitate chemical depolymerization.

The depolymerization reaction in the present invention uses a method of glycolysis (Alcoholysis), or hydrolysis (Hydrolysis).

Chemicals used in glycolissis are glycols which are α and ω-diol. Specifically, ethylene glycol (hereinafter abbreviated as EG) and propylene glycol (hereinafter referred to as PG) are used. Abbreviated), 1,4-butanediol (abbreviated to BD), 1,5-pentanediol (abbreviated to PD), 1,6-hexanediol (1, 6-Hexanediol, hereinafter abbreviated as HD).

In the glycolysis depolymerization reaction, the amount of glycol varies depending on the degree of copolymerization of the final product, but it is appropriate to add a molar concentration of 0.5 to 10 times that of the number of moles of PTT.

If the molar concentration is less than 0.5 times, the melt viscosity in the reaction system is too high, so that the progress of the reaction is difficult. If the molar concentration is higher than 10 times, the reaction rate can be increased but it is not economical.

In addition, since the glycol depolymerization is a reversible reaction of the polymerization reaction, any material used as a catalyst for the transesterification reaction or the copolymerization reaction during the polyester polymerization can be used as the catalyst of the glycolissis.

Specifically, antimony compounds such as antimony trioxide and antimony acetate, titanate compounds such as tetrabutyl titanate and tetrabutyl isopropyl titanate, tin compounds such as monobutyl tin oxide, and zinc and lead Acetate such as cobalt, cerium, manganese, cadmium, magnesium, calcium, potassium, sodium, lithium, and the like can be used.

The type and content of these catalysts can be changed depending on the type and amount of copolymerized monomers and the intended use. However, it is generally appropriate to select a suitable range according to the amount of PTT waste to be depolymerized. Do.

When the content of the catalyst is lower than 0.001% by weight, it is difficult to show activity as a catalyst. When the content of the catalyst is higher than 5% by weight, the catalyst acts as a foreign material in the final polymer, resulting in lower work processability and more side reactions. There is a problem that increases.

The copolyester oligomer prepared by such depolymerization can produce a high degree of polymerization of the copolyester by a conventional copolymerization reaction.

At any point in the depolymerization and copolymerization process, various kinds of additives may be added to improve the properties of the polymer.

The types of additives are as follows.

When used as a fiber, a quencher may be added.

As a matting agent, nearly titanium dioxide is mainly used, and the amount thereof is suitably 5% by weight or less depending on the use of the fiber used.

When more than 5% by weight, a large number of coarse particles are generated during polymerization, which may cause problems such as an increase in pack pressure during spinning.

The particle diameter of the titanium dioxide to be added is suitably 0.01 to 5 microns.

In addition, a thermal stabilizer may be added depending on the application. As a thermal stabilizer, phosphorus compounds such as phosphoric acid, trimethyl phosphate, triethyl phosphate, and triphenyl phosphate are mainly used. The content of the thermal stabilizer is 500 ppm or less based on the phosphorus atom.

In the case of more than 500ppm, the thermal stabilizer deteriorates the reaction by degrading the activity of the catalyst during the depolymerization reaction or the copolymerization reaction, thereby causing thermal decomposition.

In addition, a hindered phenol (Hindered phenol) or a HLS (Hindered Amine Light Stabilizer, HALS) thermal stabilizer may be used as an antioxidant and light stabilizer.

The content is preferably 2% by weight or less relative to the polymer.

If the amount is more than 2% by weight, the polymerization is delayed like the heat stabilizer.

You can also add colorants to improve the color.

As the colorant, inorganic additives such as cobalt acetate and organic toners such as polyciner red or blue of Clariant can be used.

Inorganic additives such as cobalt acetate may be added at 200 ppm or less relative to the polymer based on the metal atom of the compound.

If it is more than 200 ppm, these precipitate in the polymer and are likely to cause problems such as deterioration in spinning workability.

The organic toner is advantageously added at 50 ppm or less relative to the polymer.

If it is more than 50 ppm, it is difficult to adjust the color to the desired range, and the manufacturing cost is increased because the organic toner price is high.

Copolymers of copolyesters include all catalysts used in depolymerization, antimony-based catalysts such as antimony trioxide and antimony acetate used as general polyester copolymerization catalysts, tetrabutyl titanate and tetraisopropyl titanate, etc. Titanium-based catalysts and germanium-based catalysts such as germanium dioxide may be used, or all of them may be mixed or used separately.

Their content is preferably 0.001 to 0.5% by weight based on the metal content of the catalyst.

However, when the antimony catalyst is used alone, the price is low but the activity is low, so it is difficult to increase the degree of polymerization, so it is difficult to use the antimony catalyst alone.

In addition, since the titanium catalyst and the germanium catalyst are more expensive than the antimony catalyst, it is also possible to use an antimony catalyst in parallel.

Therefore, in the case of using an antimony catalyst, a titanium catalyst or a germanium catalyst must be used in parallel.

If it is less than 0.001% by weight, the polymerization reaction may be delayed, and the above-described problems may occur. If the amount is more than 0.5% by weight, the side reactions may be increased, and there may be a lot of foreign matter in the polymer.

The depolymerization reaction temperature is in the range of Tb to Tb + 80 ° C based on the boiling point of the glycol participating in the depolymerization reaction (hereinafter abbreviated as Tb).

When it is lower than Tb, the fluidity of the PTT polymer to the glycol is low, and the progress of the reaction is slow. When it is higher than Tb + 80 ° C., it is difficult to control the reaction due to the dolby phenomenon of glycol.

The temperature of the polycondensation reaction may be in the range of Tm + 10 ° C. to Tm + 80 ° C. on the basis of the melting point (hereinafter, abbreviated as Tm) of the copolyester finally produced.

If it is lower than Tm + 10 ℃, the reaction does not proceed because the melt viscosity of the reactant is too high or the reactant is not completely dissolved.If it is higher than Tm + 80 ℃, the reaction rate is fast but pyrolysis and side reaction speed are also fast. The quality is degraded.

In the case where the copolyester is made of an amorphous copolymer (generally, when the molar ratio of PTT occupies 30 to 70 mol% of the entire polymer), the polycondensation reaction temperature is 180 ° C to 280 ° C. It is suitable.

The present invention will be described in detail by the following examples.

In the present invention, PTT, which is a raw material for depolymerization, was cut to 75 cm of 75 denier / 36 filament manufactured by Hyosung Textile Research Institute.

Physical properties according to the present invention were evaluated as follows.

Ultimate viscosity (IV)

Phenol / 1,1,2,2-tetrachloroethane was mixed with 6/4 (weight) as a solvent, and it measured by the Ubelide viscometer at 25 degreeC.

2. Measurement of By-products

The prepared copolyester was hydrolyzed with monoethanolamine and measured by gas chromatography.

3. Measurement of terminal carboxyl group

The prepared copolyester was dissolved in benzyl alcohol and analyzed by reverse titration with KOH.

4. PTT content (mol%) in copolyester

The prepared copolyester was dissolved in trichloroacetic acid and analyzed by proton NMR using Nuclear Magnetic Resonance.

5. Thermal Analysis

Melting temperature (Tm) of the polymer was analyzed by defining the temperature of the peak point in a differential scanning calorimetry (DSC) chart using Perkin-Elmer's DSC-7.

Example 1

Into a reactor equipped with a stirrer and an effluent column, EG 620g (EG is 5 mol times the PTT repeating unit) containing 0.4 g of zinc acetate (Zinc Acetate) was added as a depolymerization catalyst.

In addition to stirring, the reactor was heated up and left for 2 hours while the stirring was continued when the temperature inside the reactor became 220 ° C.

This was transferred to a copolymerization reactor, the temperature was raised to 270 ° C., and then 10 g of EG kept at 120 ° C. containing 0.3 g of tetrabutyl titanate was added as a copolymerization catalyst, followed by vacuum, followed by a reaction similar to that of a conventional polyester copolymerization reaction. Copolymer was prepared by polymerization, and the physical properties of the prepared copolyester are shown in Table 1.

Example 2

Into a reactor equipped with a stirrer and an effluent column, 412 g of PTT and 900 g of 1,4 butanediol (BD) containing 0.4 g of zinc acetate (Zinc Acetate) as a depolymerization catalyst were added (BD is 5 moles of the PTT repeating unit). .

In addition to stirring, the temperature of the reactor was increased, and the reaction temperature was allowed to stand for 2 hours while the stirring was continued.

This was transferred to a copolymerization reactor, the temperature was raised to 260 ° C., and then 10 g of BD kept at 120 ° C. containing 0.3 g of tetrabutyl titanate was added as a copolymerization catalyst, followed by vacuum, followed by a reaction similar to that of a conventional polyester copolymerization reaction. Copolymer was prepared by polymerization, and the physical properties of the prepared copolyester are shown in Table 1.

Example 3

Table 1 shows the physical properties of the copolyester prepared in the same manner as in Example 1 except that 0.05 g of phosphoric acid was added to the initial EG feed as a heat stabilizer.

Example 4

10 g of EG solution in which 0.05 g of germanium dioxide was dissolved as a copolymerization catalyst was added thereto, and 5 minutes thereafter, 10 g of EG kept at 120 ° C. containing 0.2 g of tetrabutyl titanate was added. Table 1 shows the physical properties of the prepared copolyester.

Example 5

By using the copolyester prepared in Example 1 to spin at a spinning temperature of 275 ℃, spinning speed 3,200m / min to prepare a semi-drawn yarn of 115 denier / 36 filaments, and then stretched to draw a 75 denier / 36 filament Prepared.

The strength was 4.5g / d, elongation 50%, non-shrinkage rate 8.5%, and the same yarns (75 denier / 36 filaments) made of PET and PTT were used at 110 ℃ and 130 ℃ using high pressure dyes, respectively. As a result of dyeing, the adsorption amount of dye was higher than that of PET and PTT under any conditions.

Comparative Example 1

It was prepared in the same manner as in Example 1 except that antimony trioxide was used instead of tetrabutyl titanate as a copolymer catalyst.

<Table 1>

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Intrinsic Viscosity IV (dl / g) 0.79 0.68 0.74 0.72 0.34 PTT content (mol%) 72 44 74 73 71 Tm (℃) * 197 ND 194 196 195 CEG (meq / Kg) 34 32 36 31 36 DPE (% by weight) 0.7 0.6 0.7 0.7 0.7 DEG (% by weight) 0.3 0 0.4 0.3 0.4 THF (% by weight) 0 3.1 0 0 0

* The melting exothermic peak on DSC is so small that accurate values are difficult to analyze and no ND appears at all

The present invention can protect the environment by recycling the resins and fibers made of PTT and the wastes generated during its manufacture without incineration, and the copolyester polymers prepared using such wastes are used for resins or fibers. This is possible.

The copolymer of the present invention has substantially similar physical properties to copolyesters prepared from conventional raw materials without using waste, and in particular, has a low melting temperature, thereby making it possible to produce a polymer having improved processability.

Claims (6)

Copolyester of formula (1) prepared using polytrimethylene terephthalate waste, having an ultimate viscosity of 0.5 dl / g or more, a melting temperature of 255 ° C. or less, and a terminal carboxyl group value of 50 meq / Kg KOH or less, A copolyester polymer, characterized in that the by-products dihydroxypropyl ether, dihydroxyethyl ether, tetrahydrofuran content of 4% by weight or less, 4% by weight or less, 6% by weight or less, respectively. However, a is an integer of 2-6, m + n is 100, 0 <= m <n100, and m and n represent each mole fraction. The copolyester polymer according to claim 1, wherein the polytrimethylene terephthalate waste is a fiber. PTH wastes were depolymerized by ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol at 0.5 to 10 times the number of moles of PTT units. After, at least one selected from antimony, titanium, germanium-based catalyst copolymerization method characterized in that the copolymerization. The method according to claim 3, wherein the depolymerization temperature is in the range of Tb to Tb + 80 ° C based on the boiling point (Tb) of the glycol used. The method of claim 3, wherein the copolymerization temperature is Tm + 10 ° C ~ Tm + 80 ° C based on the melting point (Tm) of the copolyester finally produced, or 180 ~ 280 ° C when Tm is not present Method for producing a copolyester polymer. The method according to claim 3, wherein the content of the catalyst is 0.001 to 0.5% by weight based on the metal content of the catalyst to be added.