KR950002610B1 - Method of producing polyester-composition - Google Patents

Abstract

The fire retardant polyester is prepd. by the steps of : adding 0.001-0.1wt% of a fluorescence enhancing agent based on bisbenoxazol of formul a (IV); adding the cpd. (I) and the cpd. (II) at ester-exchaing reaction or polymerization to polycondense at below 280 deg.C; liquid-polymerizing to solid-polymerize; polycondensating randomly the cpd. (III) which is the product of the reaction of the cpd. (I) and (II), and is a fire retardant cpd., onto the main chain of the polyester. In the formulas, R1 is an ester formable functional gp. of monovalence; R2 and R3 are same or not each halogen, C1-10 hydrocarbon or R1; A and A' are an organic gp. of di-or tri-valence; n1 is 1-2; n2,n3 are 0-4.

Description

Manufacturing method of flame retardant polyester

The field name relates to a method for producing a flame retardant polyester characterized in that copolymerization of a flame retardant compound in the preparation of a polyester produced by the reaction of a diol with dicarboxylic acid or an ester thereof.

In general, polyester is excellent in mechanical properties, thermal properties, moldability, chemical resistance and is widely used as a fiber, film or plastic products. However, polyester is easy to burn because it is almost made up of only three elements of carbon, oxygen, hydrogen, especially when used as a fiber, the risk of fire.

Therefore, the necessity of flame retardancy is calculated | required greatly in various moldings including a fiber.

Conventionally, a method of imparting flame retardancy to a linear polyester includes a surface treatment method of coating or impregnating a flame retardant on a surface of a fiber in a post-spinning process, and a method of complex spinning of mixed spinning material by adding a non-reactive flame retardant in a step before spinning after polymerization. In addition, a method of copolymerizing or blending a flame retardant during the polymer production during the polymerization process is limited.

Among these methods, the method of copolymerizing by adding a flame retardant is most advantageous in terms of excellent durability, flame retardant performance, and low physical properties. For this purpose, various phosphorus compounds and halogen compounds are conventionally used. have.

However, when halogen-containing flame retardants are added to the polyester to impart flame retardancy to the polymer, halogen compounds tend to be thermally decomposed at high temperatures, which greatly affects the fiber properties. The degradation of the is easily brought.

In addition, when adding a phosphorus compound at the time of polyester manufacture, phosphonic acid esters, such as a triphenyl phosphate, and phosphonic acid, such as a benzene phosphonic acid derivative, have conventionally been used, but when using such a compound, Not only does the activity of the catalyst decrease, the melting point of the polymer obtained due to the formation of ether bonds decreases, or the gelation of the polymer is caused, but also the flame retardancy is excellent because of the large scattering of phosphorus compounds in the polyester manufacturing system. It is difficult to obtain a polymer, and there are various problems such as contamination of the environment by scattered phosphorus compounds.

Then, in order to solve this problem, a suitable phosphorus compound was searched. As a result, when the phosphonic acid derivative represented by the following general formula (IV) is used, the linear polyester is almost free of problems in the same way as the polymerization of ordinary polyester. It can be produced, and the obtained polyester has been reported to have excellent flame retardancy while having extremely low content of ether bonds.

(Wherein R ' ₁ and R' ₂ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, R ' ₃ and R' ₄ are hydrogen atoms or hydrocarbon groups having 1 to 4 carbon atoms)

However, when the phosphonic acid derivative represented by the general formula (IV) is used in the production of flame retardant polyester, since the phosphonic acid derivative is a trifunctional compound, there is a possibility of causing a crosslinking reaction, Incorporation is inevitable.

Therefore, when melt-molding such flame-resistant polyester to produce molded articles such as fibers and films, the physical properties of the molded articles are lowered or the operability is lowered.

On the other hand, Korean Patent No. 79-1137 discloses a flame-resistant polyester from at least one dicarboxylic acid or ester-forming derivative thereof and at least one diol or ester-forming derivative thereof, or at least one oxycarboxylic acid or ester-forming derivative thereof. In any of the steps of transesterification and polycondensation, a method of reacting by adding a phosphorus compound represented by the following general formula (III) is described so that the content of phosphorus in the polyester is 500 to 50,000 ppm.

(Wherein R ¹ is a monovalent ester-forming functional group, R ² and R ³ are the same or different and each is selected from a halogen atom, a hydrocarbon group of 1 to 10 carbon atoms and R ', A and A 'Is a divalent or trivalent organic residue, n ₁ is 1 or 2, n ₂ and n ₃ are each an integer of 0 to 4)

However, the above method has improved flame retardancy than other known methods, but has a disadvantage in that the viscosity decreases, the trimming phenomenon occurs and the radioactivity deteriorates due to the reaction for a long time above the decomposition temperature of the phosphorus compound, and the color tone is poor.

Accordingly, an object of the present invention is to provide a polyester having excellent flame retardancy and no viscosity decrease, excellent radiation property and good color tone by supplementing the disadvantages of Korean Patent No. 79-1137.

In order to achieve the above object as well as another object that is easily expressed in the present invention, when preparing a general polyester produced with ester-forming derivatives of diol and dicarboxylic acid and dicarboxylic acid, the bisbenzane of the following general formula (IV) 0.001 to 0.1 wt% of the resulting polymer is added to the sol-based fluorescent brightener, and the compounds of the following general formulas (I) and (II) are added during the transesterification or polymerization reaction to be polycondensed at a temperature of 280 DEG C or lower to some extent. After the liquid phase polymerization was carried out until the polymerization degree was reached, the solid phase polymerization was carried out again to finally copolymerize the flame retardant compound of general formula (III), which is a reaction product of general formulas (I) and (II), in the polyester main chain randomly. By doing so, it was possible to produce a polyester excellent in flame retardancy.

(Wherein R ¹ is a monovalent ester-forming functional group, R ² and R ³ are the same or different and each is selected from a halogen atom, a hydrocarbon group of 1 to 10 carbon atoms and R ', A and A 'Is a divalent or trivalent organic residue, n ₁ is 1 or 2, n ₂ and n ₃ are each an integer of 0 to 4)

The phosphorus compound of formula (I) is 9,10-dihydro-oxa-10-phosphor phenanthrene-10-oxide (hereinafter referred to as DOP) or a benzene nucleus substituent thereof. II) is an unsaturated compound having an ester forming functional group, for example, selected from dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, acrylic acid, methacrylic acid, mesaconic acid, citraconic acid, glutamic acid or their anhydrides and esterified products It is preferable to use an oxycarboxylic acid such as butenolic acid or an unsaturated glycol such as 2-butene-1, 4-diol and 3-butene-1, 2-diol. Especially as an unsaturated compound, itaconic acid, the lower alkyl ester of itaconic acid, or an acid anhydride is preferable.

In the case of preparing the flame-retardant polyester composition of the present invention by adding the above-mentioned unsaturated compound having a phosphorus compound and an ester-forming functional group during the polymerization step and adding a reaction, the phosphorus content in the obtained polymer should be 500 to 50,000 ppm. In particular, in the polyester for fibers, it is preferable to adjust the amount of each starting material to be 1,000 to 10,000 ppm, and the DOP or its benzene-nuclear substituent and the unsaturated compound are used so that the molar ratio is approximately 1: 1. Although it is preferable, either one may be used slightly in excess, and it is preferable to dissolve in an appropriate amount of diol at the time of input.

In addition, in order to improve the color tone of the flame retardant polyester of the present invention, the bisbenzoxazol-based forming bleaching agent of the general formula (IV) is added to 0.001 to 0.1 wt%, more preferably 0.01 to 0.05 wt% of the resulting polymer. Slurry to an appropriate amount of diol and introduced during the transesterification or polycondensation reaction, in order to minimize the thermal decomposition of the polymer and flame retardant during the polycondensation process, liquid phase polymerization to a certain degree of polymerization, at a temperature below the start temperature of decomposition of the flame retardant In addition, it is possible to prevent the trimming phenomenon due to the decomposition products of the flame retardant in the copolymer which does not occur when the solid phase polymerization is performed by performing the solid phase polymerization to the desired degree of polymerization to improve thermal stability, radioactivity and flame retardancy, and at the same time, it is not accompanied by thermal decomposition of the copolymer. It is easy to adjust the viscosity without the state.

In the present invention, a method of adding dicarboxylic acid and ester-forming derivatives thereof to increase the copolymerization rate of general formula (III) is to add a minimum amount at the beginning of the transesterification reaction and the remaining amount in the transesterification stage, more specifically, It is preferable to add methanol or water when the amount of water outflow reaches 25 to 30% of the total outflow. This facilitates the formation of general formula (III) and gives the maximum reaction time between the compound of general formula (III) and diol. To do this.

The addition time of the general formulas (I) and (II) is preferably dissolved completely in an appropriate amount of diol at the beginning of the transesterification reaction.

When the liquid phase polymerization was carried out at the initial reaction temperature of 140 to 240 ° C., the latter reaction temperature of 240 to 280 ° C., and the vacuum degree of 0.1 to 0.2 mmHg in the same manner as described above, 60-80% of the desired final intrinsic viscosity was obtained. When the viscosity reaches 0.4 to 0.5, it is made of pellets, dried, preliminarily crystallized at 180 to 220 ° C for 0.5 to 1.5 hours, and first heated at about 170 to 190 ° C to make the moisture content less than 0.02% by weight. After heating at 235 ° C. for a second time to reach a solid phase polymerization temperature, the solid phase polymerization may be performed at 200 to 230 ° C., followed by cooling with nitrogen gas at room temperature to prepare a flame retardant polyester polymer.

The polyester polymer according to the present invention has advantages such as low intrinsic viscosity lowering and excellent radioactivity, color tone, and flame retardancy compared to polymers produced by a conventional PET production method.

The intrinsic viscosity of the prepared flame retardant polyester polymer was measured in an orthochloro phenol solution at 30 ° C., and the melting point was determined using a Model 990 differential scanning calorimeter from DuPont, USA. The degree of coloration of the copolymer was measured by using an automatic colorimetric colorimeter (ND-101 D type) and the L value (brightness) and b value (yellowness), and the polymer prepared for evaluating thermal stability was subjected to a rotary electric dryer (240). Heat treatment was performed to compare and judge the color with the standard color to determine heat resistance.

The polyester polymer was stretched after spinning to prepare a knitted fabric, and the flame resistance was evaluated. The limit oxygen index (LOI) value was measured by an oxygen coefficient flammability gauge based on ASTM-D-2863-70, and the number of contact salts was JISL-. Based on 1092D method, it evaluated by the 45 degree coil method by the micro burner, respectively. Radioactivity also indicated the number of rounds in the rounds per hour.

Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1

3034 parts of diethyl terephthalate, 3760 parts of ethylene glycol, 210 parts (0.97 mole) of DOP, 154 parts (0.97 mole) of dimethyl itaconic acid, 3 parts of antimony trioxide, and 6 parts of calcium acetate were placed in a transesterification reactor and subjected to heat stirring. When the methanol flow rate reached about 730 ml (reactor internal temperature: 200-210 ° C), 3034 parts of dimethyl telephthalate and 697 parts of ethylene glycol were added, and methanol was completely removed while heating the reactor temperature to 230-240 ° C. Completed. The product was transferred to a polymerization reactor, and 6 parts of phosphorous acid, 24 parts of titanium dioxide, and 1.8 parts of compound (IV) were slurried in an appropriate amount of ethylene glycol, and the temperature inside the reactor was not reduced to 280 ° C under reduced pressure under 0.1 to 0.2 mmHg. The liquid phase polymerization reaction was completed to obtain a polymer having an intrinsic viscosity of 0.4 to 0.45. After drying the resulting polymer pellets in a nitrogen atmosphere at about 180 ℃ preheating the crystallization, when the moisture content is 0.02% or less, the second heating is carried out to obtain a polymer produced by the solid-phase polymerization at a temperature of 200 ~ 230 ℃ After cooling to nitrogen gas at room temperature to prepare a final polymer, the physical properties were evaluated by spinning and stretching. The evaluation results are shown in Table 1.

Example 2

The physical properties of the compound (IV) were evaluated in the same manner as in Example 1 except that 1.2 parts of the compound (IV) were added thereto. The results are shown in Table 1.

Example 3

After the same procedure as in Example 1, except that 2.4 parts of Compound (IV) was added, the physical properties thereof were evaluated. The results are shown in Table 1.

Example 4

The physical properties were evaluated after the same procedure as in Example 1 except that 175 parts (0.81 mole) of DOP and 128 parts (0.81 mole) of dimethyl itaconic acid were added. The results are shown in Table 1.

Example 5

Except having added 245 parts (1.13 mol) of DOP and 180 parts (1.13 mol) of dimethyl itaconic acid, it carried out similarly to Example 1, and evaluated the physical property. The results are shown in Table 1.

Comparative Example 1

Except not adding compound (IV), it carried out similarly to Example 1, and evaluated the physical property. The results are shown in Table 1.

Comparative Example 2

The physical properties were evaluated after the same procedure as in Example 1 except that the reaction was completed by liquid phase polymerization without performing solid phase polymerization. The results are shown in Table 1.

Comparative Example 3

6,000 parts of dimethyl terephthalate and 3625 parts of ethylene glycol were added at the beginning of the transesterification reaction, and the physical properties were evaluated after the compound PET (I) and (II) were not added at all and the solid phase polymerization was performed. The results are shown in Table 1.

TABLE 1

Claims (1)

In preparing a polyester produced from diol and dicarboxylic acid and dicarboxylic acid or ester-forming derivative thereof, a flame retardant compound of the following general formula (III) is copolymerized in a polyester main chain. In addition, the bisbenxazole-based fluorescent brightener of the general formula (IV) is added so as to be 0.001 to 0.1 wt% with respect to the resulting polymer, and the compounds of the general formulas (I) and (II) are added and reacted during the transesterification reaction. The compound of formula (IIII) is allowed to copolymerize in the polyester backbone, but after the transesterification reaction, the compound is liquid-polymerized until the intrinsic viscosity corresponding to 60 to 80% of the final intrinsic viscosity during polycondensation, and then again the compound of formula (III) A method for producing a flame retardant polymer, characterized in that the solid phase reaction below the decomposition temperature. (Wherein R ¹ is a monovalent ester-forming functional group, R ² and R ³ are the same or different and each is selected from a halogen atom, a hydrocarbon group of 1 to 10 carbon atoms and R ', A and A 'Is a divalent or trivalent organic residue, n ₁ is 1 or 2, n ₂ and n ₃ are each an integer of 0 to 4)