Polyester resins for preparing CD-PET and CD-PET composite resins containing the same.

Abstract

This invention relates to a polyester resin, a cationic dye-polyethylene terephthalate composite resin using the same, and to a polyester resin for preparing cationic dye-polyethylene terephthalate that ensures excellent dyeability of cationic dyes on nonionic polyethylene terephthalate resins, a cationic dye-polyethylene terephthalate composite resin prepared therefrom, and cationic dye-polyethylene terephthalate fibers, raw yarns, and circular knitted fabrics with excellent dyeing rates of cationic dyes prepared therefrom.

Description

Technical Field

[0001] This invention relates to a cationic dye (CD)-PET composite resin prepared using recycled polyethylene terephthalate (PET) resin, a polyester resin for preparing cationic dye-PET composite resin that can be cationic dyed when used to prepare fibers and / or yarns, and fibers and / or yarns, circular knitted fabrics, etc. that can be dyed with cationic dyes. Background Technology

[0002] Typically, as a method for preparing fibers capable of cationic dyeing, when polyester fibers are prepared using terephthalic acid (TPA) and ethylene glycol (EG), a known modifier that can bind to cationic dye ions is mixed with terephthalic acid and ethylene glycol for direct esterification.

[0003] To impart cationic dyeing properties to modified polyester products, such as recycled polyester, flame-retardant polyester, high-shrinkage polyester, and modified polyester containing high concentrations of TiO2, it is necessary to prepare them by adding modifiers to each polymerization step via transesterification.

[0004] To prepare conventional recycled polyester, ethylene glycol is first added to flakes prepared in a bottle. After melting at 180°C–240°C, glycolysis is carried out under nitrogen pressure to prepare bishydroxyethyl terephthalate (BHT). Recycled polyester is then prepared via polycondensation. Because nitrogen pressure is applied during the ES reaction, dimethyl sulfide (DMS), which enables cationic dyeing, must be added during the polymerization reaction. To facilitate this addition, it must be added in oligomer form, where the modifier has undergone a first reaction with ethylene glycol. Due to the aforementioned process, a higher amount of diethylene glycol (DEG) is produced compared to existing cationic dyeable polyester products, leading to differences in spinning operability and final dyeability.

[0005] Furthermore, in the case of conventional polyester, there are no sites for ionic interaction with ionic dyes; therefore, only disperse dyes are used for dyeing. Disperse dyes not only fail to provide bright and deep colors, but also have poor reliability for sublimation treatment.

[0006] Sodium 5-sulfoisophthalate (Na-SIPA) is typically used as a cationic comonomer to prepare cationic dyeable polyesters (cationic dye-polyethylene terephthalate (CD-PET)) through copolymerization, thereby enabling the use of cationic dyes on fibers and filaments.

[0007] Sodium 5-sulfoisophthalate used in the preparation of the cationic dye polyethylene terephthalate (PET) has acidic properties. During the esterification step of PET, the formation of diethylene glycol increases, lowering the melting point. Due to its acidic nature, it promotes the aggregation of TiO2, thus making fiber preparation difficult. To address this problem, attempts have been made at the end or beginning of the esterification step to provide bis(hydroxyethyl) isophthalate-5-sulfonate, i.e., the oligomer form resulting from the first reaction of dimethyl sulfide with ethylene glycol. However, during the preparation of bis(hydroxyethyl) isophthalate-5-sulfonate, the formation of trimers, tetramers, and oligomers leads to poor spinnability.

[0008] In particular, in order to prepare recycled polyester resin that can be dyed with cationic dyes, in the esterification polymerization step, after glycolytic depolymerization with the sheet provided from the bottle to generate diethyl terephthalate under nitrogen pressure, bis(hydroxyethyl) isophthalate-5-sulfonate needs to be added in the polymerization step. However, as mentioned above, the diethylene glycol yield increases, the melting point decreases, and oligomers are formed, which results in poor spinnability.

[0009] As mentioned above, in the case of modified copolyesters, i.e., flame-retardant polyesters, polyesters containing high concentrations of TiO2, polyesters with potential crimping properties, recycled polyesters, etc., when dimethyl sulfide is used to enable cationic dyeing, the production of diethylene glycol increases. Due to its acidic properties, it aggregates with TiO2, or it cannot be added during esterification and can only be added in the form of bis(hydroxyethyl) isophthalate-5-sulfonate, resulting in the production of excessive oligomers and poor spinnability.

[0010] To improve the above-mentioned problems, cationic dye-polyethylene terephthalate (PET) fibers and recycled cationic dye polyesters can be prepared by using a composite resin (or masterbatch) for preparing cationic dye-PET fibers. Korean Patent Application No. 10-2019-7009748 describes a modified polyester masterbatch for use in fabrics and a method for preparing the same. It involves a polyester masterbatch selected from dicarboxylic acid aromatics and / or aliphatic acids, and describes a preparation method involving polycondensation by adding up to 40% dimethyl sulfide and a high molecular weight polyethylene glycol. However, when high concentrations and high molecular weight polyols such as polyethylene glycol are added, the moisture adsorption rate during the sheet drying process for preparing cationic dye-PET fibers increases, leading to problems such as yarn breakage and unwinding during the preparation of the precursor yarn. Summary of the Invention

[0011] The technical problem that the invention aims to solve

[0012] This invention addresses the aforementioned problems by determining the optimal components and composition ratios of a polyester resin for preparing cationic dye-polyethylene terephthalate (PET) resin, ensuring excellent dyeing properties of cationic dyes on recycled polyethylene terephthalate (PET) resin. The PET resin prepared using the aforementioned polyester resin for preparing PET dye-polyethylene terephthalate minimizes moisture adsorption and provides a precursor fiber with improved dyeing efficiency for cationic dyes. In other words, this invention provides a polyester resin for preparing PET dye-polyethylene terephthalate (PET), a PET resin containing the same, and a precursor fiber prepared using the same.

[0013] Technical means to solve the problem

[0014] The polyester resin for preparing cation dye-polyethylene terephthalate of the present invention is a polymer formed by polycondensation of an ester compound, wherein the ester compound is formed by esterification of an acid component and a diol component, wherein the acid component comprises a compound as shown in Chemical Formula 1 below, a fatty acid and a carboxylic acid, and the diol component comprises ethylene glycol or a mixture of diols, wherein the mixture of diols comprises a linear diol and a branched diol as shown in Chemical Formula 2 below.

[0015] [Chemical Formula 1]:

[0016] In the chemical formula 1, the R 1 and R 2 Each is independently a straight-chain alkyl group of C1 to C5 or a branched alkyl group of C3 to C5, and K is a monovalent cation.

[0017] [Chemical Formula 2]:

[0018] In the chemical formula 2, R 1 and R 4 Each is independently a hydrogen atom, C1 to C2. 10 Alkyl, C2-C5 alkylene, C5-C6 cycloalkyl or phenyl, R 2 and R 3 Each is independently a C1–C5 alkylene group, but excluding R. 1 and R 4 The case where all atoms are hydrogen atoms.

[0019] In a preferred embodiment of the present invention, the acid component may comprise 7 mol% to 15 mol% of the compound represented by Chemical Formula 1, 7 mol% to 10 mol% of the fatty acid, and the remainder being a carboxylic acid.

[0020] In a preferred embodiment of the present invention, the fatty acid may include one or more of bisaccharide, succinic acid and glutaric acid.

[0021] In a preferred embodiment of the present invention, the carboxylic acid may contain components selected from C6 to C4. 14 Aromatic polycarboxylic acids and C2-C 16 One or more of the aliphatic polycarboxylic acids.

[0022] As a preferred embodiment of the present invention, C6 to C 14 Aromatic polycarboxylic acids may contain terephthalic acid alone, or both terephthalic acid and isophthalic acid.

[0023] As a preferred embodiment of the present invention, the diol mixture in the diol component may contain 4 mol% to 10 mol% of the branched diol and the remaining amount of straight-chain diol.

[0024] In a preferred embodiment of the present invention, the straight-chain diol may comprise C1 to C5 straight-chain diols.

[0025] As a preferred embodiment of the present invention, the polyester resin used to prepare cationic dye-polyethylene terephthalate can be a polymer with a degree of polymerization of 120 to 180.

[0026] As a preferred embodiment of the present invention, the polyester resin used to prepare cationic dye-polyethylene terephthalate has an intrinsic viscosity of 0.40 dl / g to 0.80 dl / g, a glass transition temperature (Tg) of 58°C to 75°C, and a melting temperature (Tm) of 180°C to 220°C.

[0027] Another object of the present invention is to provide a masterbatch sheet for preparing cationic dye-polyethylene terephthalate comprising the polyester resin described above for preparing cationic dye-polyethylene terephthalate.

[0028] Furthermore, another objective of the present invention is to provide a cationic dye-polyethylene terephthalate composite resin, comprising the previously disclosed polyester resin and polyethylene terephthalate resin for preparing cationic dye-polyethylene terephthalate.

[0029] In a preferred embodiment of the present invention, the cationic dye-polyethylene terephthalate composite resin may contain 10% to 35% by weight of the polyester resin and the remainder of the polyethylene terephthalate resin.

[0030] In a preferred embodiment of the present invention, the polyethylene terephthalate resin in the cationic dye-polyethylene terephthalate composite resin component may comprise recycled polyethylene terephthalate resin derived from waste products.

[0031] Another object of the present invention is to provide cationic dye-polyethylene terephthalate fibers and / or cationic dye-polyethylene terephthalate precursor fibers prepared using the aforementioned cationic dye-polyethylene terephthalate composite resin.

[0032] In a preferred embodiment of the present invention, the cationic dye-polyethylene terephthalate fiber may contain cationic dye-polyethylene terephthalate resin, cationic dye, and additives.

[0033] In a preferred embodiment of the present invention, the cationic dye-polyethylene terephthalate fiber is a raw filament of polyethylene terephthalate fiber prepared by dyeing with the cationic dye-polyethylene terephthalate composite resin, and the fiber dyed with the cationic dye can meet the surface dye concentration (K / S) of 9.0 to 15.0.

[0034] Another object of the present invention is to provide a cylindrical knitted fabric comprising the cationic dye-polyethylene terephthalate fiber and / or cationic dye-polyethylene terephthalate precursor yarn.

[0035] Another object of the present invention relates to a method for preparing the cationic dye-polyethylene terephthalate (PET) fibers and / or PET precursor fibers, which can be prepared by performing a process comprising the following steps: a first step, preparing sheets of polyester resin comprising various forms of PET resin for preparing cationic dye-polyethylene terephthalate and sheets comprising nonionic polyethylene terephthalate resin respectively; a second step, mixing a masterbatch formed by melting the sheets comprising the polyester resin and a resin formed by melting the sheets comprising nonionic polyethylene terephthalate resin, and spinning the mixture through a spinneret to form fibers; and a third step, dyeing the fibers with a cationic dye and then performing a reduction cleaning.

[0036] In a preferred embodiment of the present invention, the cationic dye may contain one or more selected from Kayacrylyellow3RL, Kayacryl Red GRL and Kayacryl Blue GSL.

[0037] In a preferred embodiment of the present invention, the spinning can be performed at a temperature of 250°C to 330°C and a spinning rate of 1500 MPM to 4500 MPM.

[0038] Invention Effects

[0039] The polyester resin of the present invention for preparing cationic dye-polyethylene terephthalate (CD-PET) fibers can significantly improve the dyeing rate when using cationic dyes to dye fibers and / or raw yarns prepared from recycled waste polyethylene terephthalate resin. The physical properties of the raw yarn can be improved by controlling the moisture content. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the process for preparing fibers and / or precursor fibers by mixing and spinning molten polyester resin (masterbatch) used to prepare cationic dye-polyethylene terephthalate with recycled polyethylene terephthalate resin. Detailed Implementation

[0041] The present invention will now be described in further detail.

[0042] Fibers prepared from recycled polyethylene terephthalate (PET) resin have a very low dyeing rate with cationic dyes. In the past, methods such as modifying recycled PET resin have been used to increase the dyeing rate of cationic dyes. However, these methods significantly reduce productivity or the physical properties of fibers prepared from recycled PET resin.

[0043] The present invention relates to the following: When preparing fibers using recycled polyethylene terephthalate resin, if the polyester resin (hereinafter referred to as "PE resin" or "masterbatch") used in the present invention for preparing cationic dye-polyethylene terephthalate is mixed and spun, the physical properties of the fibers can be prevented from decreasing, and the dyeing rate of cationic dyes can be improved.

[0044] The PE resin of this invention comprises a polymer obtained by polycondensation of an ester compound, wherein the ester compound is obtained by esterification of an esterification reactant, and the esterification reactant comprises an acid component and a diol component.

[0045] Furthermore, the acid component of the ester compound includes compounds as shown in Chemical Formula 1 below, fatty acids, and carboxylic acids.

[0046] [Chemical Formula 1]:

[0047] In the chemical formula 1, R1 and R2 are each independently a C1-C5 straight-chain alkyl group or a C3-C5 branched alkyl group, preferably a C1-C5 straight-chain alkyl group, and more preferably a C1-C3 straight-chain alkyl group. Furthermore, K is a monovalent cation, preferably Na. + or K + .

[0048] The total mol% of the acid component may contain 5 mol% to 15 mol% of the compound represented by Chemical Formula 1, preferably 6 mol% to 13 mol% of the compound represented by Chemical Formula 1, and more preferably 7 mol% to 12 mol% of the compound represented by Chemical Formula 1. If less than 5 mol% of the compound represented by Chemical Formula 1 is contained, when preparing the cationic dye-polyethylene terephthalate composite resin for preparing fibers or raw silk, there may be a problem that an excessive amount of masterbatch (or PE resin) needs to be added to achieve cationic dyeing. If more than 15 mol% of the compound represented by Chemical Formula 1 is used, the molecular weight of the polymer (or PE resin) will be too high, which may cause a sharp increase in viscosity. Therefore, it is preferable to use the components within the range described above.

[0049] Furthermore, the fatty acids in the acid component may include one or more of adipic acid, succinic acid, and glutaric acid, preferably adipic acid. The total mol% of the acid component may contain 7 mol% to 10 mol% of fatty acids, preferably 7.2 mol% to 9.5 mol% of fatty acids. If the fatty acid content is less than 5 mol%, the viscosity increase of the polymer cannot be controlled, resulting in the polymerization reaction terminating before reaching the desired intrinsic viscosity (IV) of the PE resin (0.40 dl / g to 0.80 dl / g). If the fatty acid content is greater than 10 mol%, the glass transition temperature (Tg) and melting temperature (Tm) of the PE resin are too low. Therefore, when preparing fibers or filaments from PE resin sheets, poor extrusion may occur during sheet melting and extrusion processes. When PE resin is sheeted, it needs to be dried for a long time at a low temperature below 60°C, resulting in poor drying operability.

[0050] The carboxylic acid component may contain substances selected from C6 to C6. 14 Aromatic polycarboxylic acids and C2-C 16 One or more of the aliphatic polycarboxylic acids, preferably comprising C6 to C7. 14Aromatic polycarboxylic acids.

[0051] The aromatic polycarboxylic acid may include terephthalic acid, or terephthalic acid and isophthalic acid. When isophthalic acid is used in combination, terephthalic acid and isophthalic acid are used in a molar ratio of 1:0.02 to 1:0.15. Preferably, terephthalic acid and isophthalic acid are used in a molar ratio of 1:0.04 to 1:0.10. This is beneficial to ensure that the moisture content of the flakes is low when flakes are formed and the glass transition temperature is high during the polymerization process.

[0052] The aliphatic polycarboxylic acid may include one or more selected from oxalic acid, malonic acid, succinic acid, glutaric acid, octanoic acid, citric acid, pimelic acid, azelaic acid, sebacic acid, nonanoic acid, decanoic acid, dodecanoic acid, and hexadecanoic acid.

[0053] Furthermore, when preparing esterified compounds, one or more diols selected from linear diols and branched diols can be used as diol components to reduce crystallinity and improve dyeability. Preferably, ethylene glycol or a mixture of diols can be used, wherein the mixture of diols comprises linear diols and branched diols as shown in Chemical Formula 2 below.

[0054] [Chemical Formula 2]:

[0055] In the chemical formula 2, R 1 and R 4 Each is independently a hydrogen atom, C1 to C2. 10 Alkyl, C2-C5 alkylene, C5-C6 cycloalkyl or phenyl, preferably, R 1 and R 4 Each is independently a hydrogen atom or a C1-C5 alkyl group, more preferably, R 1 and R 4 Each is independently a hydrogen atom or a C1-C3 alkyl group, but excludes R. 1 and R 4 The case where all atoms are hydrogen atoms.

[0056] Furthermore, the R in chemical formula 2 2 and R 3 Each is independently a C1 to C5 alkylene group, preferably, R 2 and R 3 Each is independently a C1 to C3 alkylene group, more preferably, R 2 and R 3 Each is an alkylene group that is independently C1 to C2.

[0057] Furthermore, the straight-chain diol in the diol mixture can be a C2-C6 straight-chain diol, preferably a C2-C4 straight-chain diol, and more preferably a C2-C3 straight-chain diol.

[0058] In the process of preparing the precursor fiber, when mixed with recycled polyethylene terephthalate (PET) or copolyester sheets, the high crystallinity can prevent dyes from fully penetrating the fiber polymer. Therefore, the glycol mixture may contain 4 mol% to 10 mol% of the branched glycols and the remainder of straight-chain glycols, preferably 4 mol% to 8 mol% of the branched glycols and the remainder of straight-chain glycols, thereby reducing crystallinity. When the branched glycol content in the glycol mixture is less than 4 mol%, the effect of controlling crystallinity is minimal, resulting in minimal improvement in dyeability. If the branched glycol content is greater than 10 mol%, the crystallinity is significantly reduced, which can lead to reduced PE resin discharge or adhesion between sheets during the drying process of the sheets used to prepare the PE resin.

[0059] The PE resin of the present invention comprises a polymer formed by the condensation of an ester compound, wherein the ester compound is formed by esterification of an acid component and a glycol component. In this process, the glycol component is based on a carboxylic acid of the acid component, and the carboxylic acid and glycol components are mixed in a molar ratio of 1:1.1 to 1:1.4, preferably in a molar ratio of 1:1.15 to 1:1.30, before the esterification and condensation reactions are performed. If the molar ratio of the glycol component is less than 1:1.1, the esterification reaction cannot be sufficiently carried out. If the molar ratio of the glycol component is greater than 1:1.4, the cost increases or the production of diethylene glycol (DEG) increases, leading to a lower melting point, thereby reducing the quality of the precursor fiber.

[0060] Furthermore, the PE resin can be prepared by performing the following steps: a first step, esterifying an esterification product containing an acid component and a glycol component to prepare an ester compound; and a second step, polycondensing the ester compound to prepare a polycondensation product.

[0061] The types and amounts of acid and glycol components used in the first step are as described above. Furthermore, the esterification reaction can be carried out at a temperature of 200°C to 265°C, preferably 220°C to 245°C. If the temperature is below 200°C, the raw materials are difficult to dissolve, thus preventing the reaction from proceeding. If the temperature is above 265°C, problems such as decomposition due to degradation or failure to obtain the desired degree of polymerization may occur.

[0062] Furthermore, the esterification reaction can be carried out at a stirring rate of 40 rpm to 80 rpm, preferably at a stirring rate of 50 rpm to 70 rpm. If the stirring rate is less than 40 rpm or greater than 80 rpm, the esterification reaction cannot be carried out sufficiently.

[0063] Furthermore, in the first step of the esterification reaction, in addition to the acid and glycol components, defoamers and / or esterification catalysts can be added and mixed before the reaction is carried out.

[0064] At this time, the defoamer can be a conventional defoamer in the art. The defoamer can be used at a weight percentage of 0.005% to 0.020% relative to the total weight percentage of the esterification reactants. Preferably, the defoamer can be used at a weight percentage of 0.008% to 0.012%.

[0065] Furthermore, the esterification catalyst may contain one or more of lithium acetate, magnesium acetate, and calcium acetate, preferably lithium acetate. Moreover, the esterification catalyst may be used at a weight percentage of 0.01 to 0.03% relative to the total weight percentage of the esterification reactants, preferably at a weight percentage of 0.015 to 0.025%.

[0066] Subsequently, the polycondensation reaction in the second step can be carried out at a temperature of 250°C to 300°C, preferably at a temperature of 260°C to 290°C. Furthermore, the polycondensation reaction can be carried out at a stirring rate of 45 rpm to 70 rpm, preferably at a stirring rate of 50 rpm to 65 rpm.

[0067] Furthermore, in the polycondensation reaction, in addition to ester compounds, one or more additives selected from antioxidants, heat stabilizers and polycondensation catalysts may be added and mixed before the polycondensation reaction is carried out.

[0068] The heat stabilizer in the additive may comprise one or more selected from trimethylphosphate, triethyl phosphate, tributyl phosphate, tributoxyethyl phosphate, tricresyl phosphate, triaryl phosphate isopropylated, hydroquinone bis-(diphenyl phosphate), and orthophosphoric acid. Furthermore, the heat stabilizer may be used at 0.05 to 0.15% by weight, preferably 0.07 to 0.13% by weight, relative to the total weight percentage of the polycondensation reactants.

[0069] Furthermore, the antioxidant may be contained alone or in combination with other antioxidants, including pentaerythritol tetrakis (3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate). The antioxidant may be used at a weight percentage of 0.05 to 0.15% relative to the total weight percentage of the polycondensation product, preferably 0.07 to 0.13%.

[0070] The polycondensation catalyst is preferably antimony trioxide, and the polycondensation catalyst can be used at a weight percentage of 0.05% to 0.15%, preferably 0.07% to 0.13%, relative to the total weight percentage of the polycondensation reactants.

[0071] The intrinsic viscosity (IV) of the PE resin of the present invention prepared by these components, composition ratios and preparation methods can be 0.40 dl / g to 0.80 dl / g, preferably 0.45 dl / g to 0.78 dl / g, and more preferably 0.55 dl / g to 0.75 dl / g.

[0072] Furthermore, the glass transition temperature (Tg) of the PE resin of the present invention can be 58°C to 75°C, preferably 60°C to 72°C, and more preferably 60°C to 68°C.

[0073] Furthermore, the melting point (Tm) of the PE resin of the present invention can be 180°C to 220°C, preferably 185°C to 220°C, and more preferably 190°C to 215°C.

[0074] The PE resin of the present invention can be sheet-processed and provided in sheet form. As a preferred example, the PE resin is pre-crystallized by multi-stage drying for 5 to 7 hours at a temperature from 70°C to 130°C, and then dried at 140°C to 160°C for 4 to 6 hours to prepare a PE resin sheet with a moisture content of less than 100 ppm. If the moisture content of the PE resin sheet is greater than 100 ppm, it will hydrolyze during the spinning process for preparing fibers and / or precursor fibers, resulting in poor spinning operability.

[0075] The PE resin of this invention can be used to prepare cationic dye-polyethylene terephthalate fibers and / or precursor fibers by the following method.

[0076] Cationic dye-polyethylene terephthalate (PET) fibers can be prepared by performing the following steps: First, prepare PE resin (polyester resin used to prepare cationic dye-PET) sheets and nonionic resin sheets respectively; Second, mix the masterbatch of the molten PE resin sheets and the resin of the molten nonionic resin sheets to prepare cationic dye-PET composite resin, and then spin it through a spinneret to form fibers; and Third, dye the fibers with cationic dyes and then perform reduction cleaning.

[0077] The PE resin and PE resin sheet mentioned in the first step are as described above.

[0078] Furthermore, the nonionic resin sheet in the first step may contain one or more of polyester resin, polyamide resin, acrylic resin, olefin resin and polyurethane resin. Preferably, it may contain polyester resin, more preferably, it may contain polyethylene terephthalate resin, and even more preferably, it may be a sheet made of recycled polyethylene terephthalate resin.

[0079] The cationic dye-polyethylene terephthalate (PET) composite resin may contain 10% to 35% by weight of the polyester resin and the remainder of PET resin. Preferably, it may contain 10% to 28% by weight of the PE resin and the remainder of PET resin. In this case, if the PE resin content exceeds 35% by weight, poor spinning may occur; therefore, it is preferable to use a resin within this range.

[0080] The second step of spinning can be achieved through methods such as... Figure 1 The method shown in the schematic diagram is performed, and more specifically, fibers are prepared by mixing and spinning through a circular die at a spinning rate of 1500 MPM to 5000 MPM, preferably 3000 MPM to 4500 MPM.

[0081] Furthermore, the second spinning step can be performed at a temperature of 250°C to 330°C, preferably at a temperature of 270°C to 320°C. If the temperature is less than 260°C, the melt flow is not smooth, thus forming brittle filaments, which have the problem of not being able to perform the winding process. If the temperature is greater than 330°C, the filaments cannot be formed due to deterioration, thus having the problem of flowing in a molten state.

[0082] The third step of dyeing with cationic dyes can be performed by conventional methods in the art, and conventional cationic dyes in the art can be used. Preferably, the cationic dye can be one or a combination of two or more selected from Kayacryl yellow 3RL, Kayacryl RedGRL and Kayacryl Blue GSL.

[0083] The cationic dyeable polyethylene terephthalate (cationic dye-polyethylene terephthalate) fibers of the present invention prepared by these components and methods can have a fineness of 50 De to 600 De, preferably 50 De to 300 De, and more preferably 50 De to 260 De.

[0084] Furthermore, the cationic dye-polyethylene terephthalate fiber prepared according to the present invention can have a strength of 2.50 g / de to 4.50 g / de, preferably 3.00 g / de to 4.30 g / de, and more preferably 3.60 g / de to 4.25 g / de.

[0085] Furthermore, the elongation of the cationic dye-polyethylene terephthalate fiber prepared according to the present invention is 30% to 45%, preferably 30% to 42%, and more preferably 32.0% to 40.0%.

[0086] Furthermore, the surface dye concentration (K / S) of the cationic dye-polyethylene terephthalate fiber of the present invention dyed with cationic dye at 600 nm is 9.0 to 15.0, preferably 10.0 to 14.5, and more preferably 10.0 to 13.5.

[0087] The present invention has been described above using examples, but these are merely illustrative and do not limit the scope of the invention. Those skilled in the art will recognize that various modifications and applications not illustrated above can be implemented without departing from the essential characteristics of the invention. For example, the various structural elements specifically shown in the examples of the invention can be modified. Furthermore, any differences relating to such modifications and applications are included within the scope of the invention as defined by the claims.

[0088] [Example]

[0089] Example 1: Preparation of polyester resin for the preparation of cationic dye-polyethylene terephthalate

[0090] (1) Add acid components, glycol components, defoamer (silicone TSF-433) and lithium acetate (esterification catalyst) to the esterification reactants, raise the temperature from 200℃ to 250℃, mix at a rate of 60 rpm and carry out the esterification reaction to prepare ester compounds (reaction products).

[0091] At this point, relative to the total mol% of the acid component, the following are used as the acid component: 7.5 mol% of the compound shown in the following chemical formula 1-1, 8 mol% of adipic acid as a fatty acid, and the remaining amount of terephthalic acid and isophthalic acid as carboxylic acids.

[0092] Furthermore, ethylene glycol is used alone as a diol component, and the diol component is used in a molar ratio of 1:1.2 based on the carboxylic acid in the acid component.

[0093] Furthermore, the defoamer is used at 0.01% by weight relative to the total weight percentage of the prepared ester reactants, and the esterification catalyst is used at 0.2% by weight relative to the total weight percentage of the prepared ester reactants.

[0094] (2) Add antioxidant (IR-1010, pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxycinnamic acid), heat stabilizer (phosphoric acid) and antimony trioxide as a polycondensation catalyst to the prepared ester compound, raise the temperature to 275°C, mix at a rate of 56 rpm and carry out a polycondensation reaction to prepare polyester resin (PE resin) as a polymer for preparing cationic dye-polyethylene terephthalate.

[0095] (3) Furthermore, after drying the prepared polyester (PE) resin in multiple stages for 6 hours at a temperature of 70℃~130℃, it is dried at a temperature of 150℃ for 5 hours to prepare a masterbatch sheet for preparing cationic dye-polyethylene terephthalate with a moisture content of less than 100ppm.

[0096] Examples 2-6 and Comparative Examples 1-4

[0097] Polyester resin for preparing cationic dye-polyethylene terephthalate and masterbatch sheets for sheet formation were prepared by the same method as in Example 1, as shown in Tables 1 and 2 below. Examples 2 to 6 and Comparative Examples 1 to 4 could be performed by changing the acid and / or diol components.

[0098] The branched diols in the diol component are diols as shown in Chemical Formula 2-1 or Chemical Formula 2-2 below.

[0099] [Chemical Formula 2-1]:

[0100] In the chemical formula 2-1, R 1 For methyl, R4 For hydrogen atoms, R 2 and R 3 It is a methylene group.

[0101] [Chemical Formula 2-2]:

[0102] In the chemical formula 2-1, R 1 and R 4 For methyl, R 2 and R 3 It is a methylene group.

[0103] Experimental Example 1: Determination of the physical properties of polyester resin used to prepare cationic dye-polyethylene terephthalate

[0104] The physical properties of the masterbatch sheets prepared in the Examples and Comparative Examples for the preparation of cationic dye-polyethylene terephthalate were tested using the following methods, and the results of these tests are shown in Tables 1 and 2 below.

[0105] (1) Inherent viscosity (IV)

[0106] Ortho-Chloro Phenol was used as a solvent and melted at 110°C with a concentration of 2.0 g / 25 m for 30 minutes. The temperature was then maintained at 25°C for 30 minutes, and the results were analyzed using an automated viscosity measuring device connected to a CANON viscometer.

[0107] (2) Glass transition temperature (Tg) and melting point (Tm)

[0108] The glass transition temperature was determined using a differential thermal analyzer under the following conditions: a heating rate of 20 °C / min.

[0109] (3) Discharge of work evaluation

[0110] When the PE resin prepared in the examples and comparative examples is sheeted, it is passed through cold water at a temperature of 10°C to 15°C and cut. At this time, it is confirmed whether dissolution occurs in the cold water and whether the sheets stick together.

[0111] (4) Evaluation of sheet drying

[0112] When preparing the masterbatch sheets prepared in the examples and comparative examples, it was confirmed whether the sheets adhered to each other and whether surface crystallization occurred during the drying process.

[0113] [Table 1]

[0114]

[0115]

[0116] [Table 2]

[0117]

[0118]

[0119] Based on the physical properties of the PE resin in Tables 1 and 2, it can be confirmed that, in the cases of Examples 1 to 6, the intrinsic viscosity is 0.64 dl / g to 0.71 dl / g, the glass transition temperature is 58°C to 64°C, the melting point is 189°C to 207°C, there is no water solubility after flake formation, the overall moisture content is low (below 140 ppm), and the adhesion occurrence temperature is high (above 65°C).

[0120] In contrast, the PE resin of Comparative Example 1, which was prepared using polyethylene glycol instead of adipic acid, had the following problems when compared with other examples and comparative examples: it had high intrinsic viscosity, low adhesion temperature when sheeted, high moisture content, and no surface crystallization.

[0121] Furthermore, in the case of Comparative Examples 2 and 3, which were prepared using diols such as those represented by Chemical Formula 2-1 or Chemical Formula 2-2 with a diol content of more than 10 mol%, the following problems were observed when compared with Examples 4 to 5: the glass transition temperature was relatively low, and the moisture content of the sheets increased significantly during sheet formation.

[0122] Furthermore, when using the PE resin of Comparative Example 4, which contains adipic acid as a fatty acid in an acid component of greater than 10 mol%, compared with Example 6, the following problems exist: the glass transition temperature and melting temperature decrease rapidly, and the moisture content of the sheet increases significantly.

[0123] Preparation Example 1: Preparation of cationic dye-polyethylene terephthalate composite resin and cationic dye-polyethylene terephthalate fiber

[0124] (1) Preparation of cationic dye-polyethylene terephthalate composite resin

[0125] Using an O-shaped two-hole spinneret, the masterbatch, which was obtained by melting the masterbatch sheet (PE resin sheet) of Example 1 prepared earlier, was mixed with the resin obtained by melting recycled polyethylene terephthalate sheet to prepare a cationic dye-polyethylene terephthalate composite resin. Then, spinning was performed at a spinning temperature of 285°C and a spinning rate of 4000 MPM to prepare cationic dye-polyethylene terephthalate fibers with a fineness of 150 De.

[0126] At this point, when spinning, the mixture of masterbatch (PE resin) sheets and recycled polyethylene terephthalate sheets is as follows: 20% by weight of polyester resin and 80% by weight of recycled polyethylene terephthalate resin.

[0127] (2) After that, the prepared fibers were dyed with KayacrylBlke GSL as a cationic dye at a concentration of 2% owf at 110°C for 45 minutes, and then reduced and washed at 80°C to complete the dyeing.

[0128] The reflectance (R) of the dyed material stained with the cationic dye was measured using a spectrophotometer (Konica Minolta E-3000). The reflectance was then substituted into the formula K / S = (1-R)² / 2R to obtain the K / S value, and the K / S value was used to evaluate the staining properties.

[0129] Preparation Examples 2-8 and Comparative Preparation Examples 1-5

[0130] Cationic dye-polyethylene terephthalate fibers were prepared using the same method as in Preparation Example 1. Instead of using the masterbatch sheet from Example 1, cationic dye-polyethylene terephthalate fibers were prepared using the masterbatch sheets prepared in Examples 2-3 and Comparative Preparation Example 1, respectively. Preparation Examples 2-8 and Comparative Preparation Examples 1-5 were carried out respectively (see Table 2 below).

[0131] Experimental Example 2: Determination of the physical properties of cationic dye-polyethylene terephthalate fiber

[0132] (1) Determine strength and elongation

[0133] The strength and elongation of the prepared fibers were determined using an automatic tensile testing machine (Textechno) at a speed of 50 cm / m and a holding distance of 50 cm. For strength and elongation, the load applied to the composite fiber under a specified force and stretched until breakage, divided by the denier value (g / de), was defined as strength. The elongation was defined as the value of the first length increase (%), expressed as a percentage.

[0134] (2) Evaluation of staining properties (darkness, K / S)

[0135] After measuring the reflectance (R) of the stained material using a spectrophotometer (Konica Minolta E-3000), the K / S value was obtained by substituting it into the formula K / S = (1-R)² / 2R, and the K / S value was used to evaluate the staining properties.

[0136] [Table 3]

[0137]

[0138]

[0139] [Table 4]

[0140]

[0141] According to Tables 3 and 4, it can be confirmed that the fibers prepared using the cationic dye-polyethylene terephthalate composite resin of Preparation Examples 1 to 6 have excellent overall mechanical properties (strength, elongation) and uniformity, and excellent dyeability with a surface dye concentration of 9.0 or higher.

[0142] In contrast, in the case of Comparative Preparation Example 1, which uses a cationic dye-polyethylene terephthalate composite resin containing more than 35% by weight of 40% polyester (PE) resin, there is a problem of very poor spinnability.

[0143] Furthermore, in the case of Comparative Preparation Example 2, which uses a cationic dye-polyethylene terephthalate composite resin containing less than 10% by weight of 6.5% by weight polyester (PE) resin, there are problems with poor strength, elongation, and dyeability.

[0144] Furthermore, in the case of Comparative Preparation Example 3 prepared using the PE resin of Comparative Example 1, the surface dye concentration (K / S) was 9.0 or less, which had the problem of poor surface dye concentration.

[0145] Through the aforementioned embodiments and preparation examples, it can be confirmed that the polyester resin of the present invention for preparing cationic dye-polyethylene terephthalate not only possesses suitable intrinsic viscosity, glass transition temperature, and melting point, but also, when sheeted, produces sheets with low moisture content and high adhesion temperature. Furthermore, it can be confirmed that the cationic dye-polyethylene terephthalate fibers prepared using the aforementioned cationic dye-polyethylene terephthalate polyester resin and waste polyethylene terephthalate resin exhibit excellent overall mechanical properties and ensure excellent cationic dyeability.

Claims

1. A polyester resin for preparing cationic dye-polyethylene terephthalate, characterized in that, It comprises: a polymer formed by the condensation of an ester compound, wherein the ester compound is formed by esterification of an acidic component and a diol component. The acid component comprises 7 mol% to 15 mol% of a compound represented by chemical formula 1 below, 7 mol% to 10 mol% of fatty acids, and the remainder being a carboxylic acid. The fatty acids include one or more of icosanoic acid, succinic acid, and glutaric acid. The carboxylic acid comprises a group selected from C6 to C6. 14 One or more of the aromatic polycarboxylic acids; The diol component comprises a diol mixture containing 4 mol% to 10 mol% of branched diols as shown in Formula 2 below and the remainder being straight-chain diols. The straight-chain diol comprises C1 to C5 straight-chain diols: [Chemical Formula 1]: In the chemical formula 1, the R 1 and R 2 Each is independently a C1–C5 straight-chain alkyl group or a C3–C5 branched alkyl group, and K is Na. + or K + ; [Chemical Formula 2]: In the chemical formula 2, R 1 and R 4 Each is independently a hydrogen atom, C1 to C2. 10 Alkyl, C2-C5 alkylene, C5-C6 cycloalkyl or phenyl, R 2 and R 3 Each is independently a C1–C5 alkylene group, but excluding R. 1 and R 4 The case where all atoms are hydrogen atoms.

2. The polyester resin for preparing cationic dye-polyethylene terephthalate according to claim 1, characterized in that, The degree of polymerization of the polymer is 120 to 180.

3. The polyester resin for preparing cationic dye-polyethylene terephthalate according to any one of claims 1 to 2, characterized in that, Its intrinsic viscosity is 0.40 dl / g to 0.80 dl / g, its glass transition temperature is 58℃ to 75℃, and its melting temperature is 180℃ to 220℃.

4. A masterbatch sheet for preparing cationic dye-polyethylene terephthalate, characterized in that, It comprises a polyester resin according to any one of claims 1 to 2.

5. A cationic dye-polyethylene terephthalate composite resin, characterized in that, It comprises 10% to 35% by weight of the polyester resin according to any one of claims 1 to 2 and the remainder of polyethylene terephthalate resin.

6. The cationic dye-polyethylene terephthalate composite resin according to claim 5, characterized in that, The polyethylene terephthalate resin comprises recycled polyethylene terephthalate resin derived from waste products.

7. A fiber, characterized in that, It includes the cationic dye-polyethylene terephthalate composite resin according to claim 5, the cationic dye, and the additives.

8. The fiber according to claim 7, characterized in that, The surface dye concentration should be between 9.0 and 15.0.

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