KR0163495B1 - Method of manufacturing polyester flat yarn - Google Patents

Abstract

The present invention aims to obtain aliphatic polyester flat yarns with excellent mechanical strength and elongation and excellent biodegradability. The technical composition is succinic acid or its ester compound, which is 97 to 99.9 mol%, as an acid component, and 0.1 to 3 mol%. A low-molecular weight organic compound having three or more phosphorus terminal carboxyl groups or anhydrides thereof, and one component selected from 1,4-butanediol or ethylene glycol as diol components comprises 70 to 97 mol% and neopentyl glycol 3 to 30 mol% Preparation of a biodegradable flat yarn characterized in that the mixture is esterified or transesterified and subjected to polycondensation reaction, and the resulting aliphatic copolyester is melted and extruded in a molding machine having a T die, followed by uniaxial stretching. As a method, this manufacturing method has a low melting point and a low crystallinity, which greatly improves molding processing properties. There is an advantage that can improve the manufacturing processability and mechanical properties.

Description

Method for preparing flat yarn made of aliphatic copolyester

The present invention relates to a method for producing a flat yarn of high molecular weight aliphatic copolyester with excellent mechanical elongation and excellent biodegradability.

Conventional general-purpose plastics are widely used in daily life because of excellent mechanical properties, chemical resistance, durability, etc., but have a disadvantage that they cannot be reduced to nature when disposed after use. In recent years, disposable packaging materials, which are rapidly increasing in demand, are not easily recovered even though they are consumed in many cases, and are often left untouched. Agricultural films are difficult to recover completely and are buried in soil, which causes a lot of obstacles to crop growth.

As the environmental pollution caused by plastic waste has emerged as a social problem, the development of a degradable resin that automatically decomposes upon disposal after a certain period of time in order to protect the environment is being actively conducted.

Such a decomposable resin is classified according to its decomposition mechanism, and is biodegradable, which is completely decomposed in nature by moisture and microorganisms, biodegradability in which starch or metal compounds added to the matrix decompose themselves or promote decomposition, and ultraviolet rays of sunlight. As a result, the main chain of the polymer is cleaved, the molecular weight is lowered, and can be classified into photodegradability, which is digested and absorbed by microorganisms.

In addition, biodegradable resins can be classified into a microorganism production type that generates microorganisms spontaneously, a natural product utilization type using natural polymers present in nature, and a synthetic polymer type that is easily decomposed by microorganisms. It is known that this is possible.

Aliphatic polyesters are obtained through condensation polymerization based on glycol and carboxylic acids, ring-opening polymerization of cyclic monomers, transesterification reactions between polyesters, and the like, and excellent physical properties and processability have been studied. In the 1960s, absorbent surgical sutures made of polyglycolide under the trade name DEXON (American Cyanamide) were developed. Recently, polylactide-based polymer materials have been developed and marketed. Union Carbide of the United States commercialized biodegradable resins under the trade name TONE. In the ring-opening polymerization of the converted ester monomer, lactone is mainly used, and is generally used to obtain a high molecular weight resin that can be molded. However, polyglycolide or polylactide, which has been used for medical purposes until now, is not suitable as a general-purpose polymer material due to its poor physical properties and economic feasibility. Polycaprolactone has a low melting point and is known to have a large problem in thermal stability and dimensional stability. .

Crystalline polymer synthesized by using a glycolide obtained by ring-opening polymerization of polyglycolide in the presence of a catalyst as a monomer has high molecular weight and glass transition temperature but has a hard and low solubility. Lactone-based polymer is flexible and has excellent molecular weight and solubility. One drawback is the low glass transition temperature. In view of this, efforts have been made to copolymerize glycolide and various lactones in the presence of a catalyst or to synthesize block copolymers of ε-caprolactone and other lactones to compensate for the shortcomings of each single polymer.

On the other hand, composite materials using natural materials such as starch and cellulose have been actively researched.However, the preparation of cellulose-filled composites with polyhydroxybutyrate and the addition of starch to general-purpose polymers such as polyolefins have biodegradability. The method is relatively easy and it is one of the most useful methods because the existing molding processing equipment can be used as it is. Hydrophilic starch has no affinity with general purpose hydrophobic polymers, so when a large amount of starch is added, it is agglomerated and deteriorates mechanical properties. Although many researches are progressing to solve this problem, introduction of such natural materials has many problems in commercialization because it is difficult to obtain quality uniformity of produced products.

Research into blending aliphatic polyester resins with other general purpose resins is also actively conducted. Examples thereof include copolymerization of polycaprolactone and polyvinyl chloride or polyvinylacetate, polystyrene, polyethylene, and polypropylene, and preparation of blends. These hybrids are used in various applications as biodegradable resins throughout life based on various physical properties and biodegradability of polycaprolactone.

On the other hand, inadequate disposal of household waste in landfills and an increase in non-degradable materials such as plastics in the garbage not only increases landfill costs, but also increases landfill requirements.

Therefore, the plastic that can be reused in the waste is the most preferable way to recycle, or diapers, sanitary towels, styropol, etc. is almost impossible to recycle, so to reduce the volume of solid waste or to fertilizer The movement to convert and commercialize is actively progressing.

On the other hand, the flat yarn (Flat Yarn) mainly used as a packaging material or agricultural subsidiary materials or forge produced therefrom is required for high corrosion resistance and high strength, high density polyethylene or polypropylene is widely used. In particular, flat yarns are widely used in the form of strings or bands, such as agricultural and marine sacks, cement sacks and civil engineering sheets, carpet bubbles. However, the use of high density polyethylene terephthalate in the production of flat yarns has many disadvantages in winding flat yarns formed by melt extrusion into a winder.

European Patent No. 569144 discloses a method for preparing a flat yarn by high molecular weight by preparing an aliphatic polyester prepolymer followed by addition reaction of diisocyanate, but this method has a longer reaction time and an isocyanate reaction depending on the additional reaction. The tricky thing to do is to adjust very delicately.

Accordingly, in view of the above, the present invention copolymerizes a low molecular weight organic compound having three or more aliphatic dicarboxylic acids, aliphatic diols and terminal carboxyl groups to obtain a high molecular weight aliphatic copolyester for molding. Melting and then extruded through a T-die and uniaxially prepared a flat yarn excellent in mechanical strength and degradability.

That is, the present invention comprises 1 to 4 constituting a diol component, comprising 97 to 99.9 mol% of succinic acid as a acid component and 0.1 to 3 mol% of a low molecular weight organic compound having three or more terminal carboxyl groups or an anhydride thereof. The aliphatic copolymer polyester having a melting point of 70 ° C. or higher and a melt index of 20 or less obtained by condensation polymerization of a mixture containing 70 to 97 mol% of one component selected from butanediol or ethylene glycol and 3 to 30 mol% of neopentyl glycol in the extruder It relates to a method for producing an aliphatic copolyester polyester flat yarn characterized in that the melt is melted in the T die to extrude and uniaxially stretch.

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

It is known to have biodegradability because it is easily hydrolyzed by the enzyme of aliphatic polyester obtained by the general condensation polymerization reaction of aliphatic dicarboxylic acid and aliphatic diol, but it has low melting point and difficult to polymerize so that the mechanical properties and processability of the processed product are There is a falling lung.

Recently, techniques for improving the polymerization of aliphatic polyesters using titanium or tin catalysts have been known due to the development of polycondensation catalysts. For example, the aliphatic polyester synthesized by the combination of succinic acid and 1,4-butanediol and the combination of succinic acid and ethylene glycol can have a high molecular weight having a melting point of 100 ° C. or more and a number average molecular weight of 10,000 or more. However, aliphatic polyesters, such as polyethylene succinate and polybutylene succinate, synthesized by such a combination have very high crystallinity, and thus the processed products themselves exhibit very hard and brittle properties during molding. It is not suitable for flat yarns.

In the present invention, 1,4-butanediol or ethylene glycol as a low molecular weight organic compound or an anhydride thereof having three or more terminal carboxyl groups having 97 to 99.9 mol% of succinic acid or 0.1 to 3 mol% of ester compound thereof as an acid component. A flat yarn was prepared using an aliphatic copolyester obtained by esterification or transesterification and condensation polymerization of a mixture consisting of 70 to 97 mol% of one component selected from 3 to 30 mol% of neopentyl glycol. . In other words, the use of a two-component mixed monomer of one component and neopentyl glycol selected from 1,4-butanediol or ethylene glycol as the diol component is a combination of succinic acid and 1,4-butanediol, a combination of succinic acid and ethylene glycol, and the like. Compared with the aliphatic polyester obtained by the combination, the melting point is lowered, but the crystallinity is lowered, so that the molding processing properties are greatly improved. Therefore, the manufacturing process and mechanical properties of the flat yarn can be improved.

It is important that 1,4-butanediol or ethylene glycol constituting the main component of the diol component used in the synthesis of the aliphatic copolyester of the present invention is 70 to 97 mol% based on the total diol component. When the 1,4-butanediol or ethylene glycol is used as the diol component paired with succinic acid or its ester compound as the acid component among the aliphatic copolymerized polyester components of the present invention, a high crystallinity polymer can be obtained. About 70 to 97 mole% of the copolymer may be used as a copolymerization ratio to obtain a complementary effect on the manufacturing process and mechanical properties of the flat yarn. When less than 70 mol% of 1,4-butanediol or ethylene glycol constituting the main component is used, the melting point of the synthesized aliphatic copolyester is very low and the cooling rate during the flat yarn manufacturing process is very low, making it unsuitable. On the other hand, when the content exceeds 97 mol%, the properties of the aliphatic polyester synthesized in the combination of succinic acid and 1,4-butanediol or in the combination of succinic acid and ethylene glycol are almost maintained, which leads to poor mechanical properties and flatness during flat yarn production. Is also very poor.

The aliphatic copolyester used in the production of the flat yarn in the present invention is an acid component constituting the constituent unit, and a low molecular weight organic compound or an anhydride thereof having a succinic acid or an ester compound thereof as a main component and three or more terminal carboxyl groups is a total acid. Condensation of the composition at 0.1 to 3 mol% per minute, 70 to 97 mol% of 1 component selected from 1,4-butanediol or ethylene glycol constituting the diol component and 3 to 30 mol% of neopentyl glycol do.

Low molecular weight organic compounds having three or more terminal carboxyl groups or anhydrides thereof include 1,3,5-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid or divalent anhydrides thereof, trimellitic acid or anhydrides thereof It is possible to use a mixture of one or two or more selected from citric acid.

The low molecular weight organic compound having three or more terminal carboxyl groups greatly improves the melt viscosity of the aliphatic copolyester of the present invention, greatly improving the elongation at the time of manufacturing flat yarns, and improving the processability, thereby making it possible to produce flat yarns with excellent mechanical properties. It becomes an argument. When a low molecular weight organic compound having three or more terminal carboxyl groups is copolymerized using more than 3 mol% or less than 01 mol%, gelation occurs during polyester synthesis, making flat yarns very difficult and diarrhea Even if manufactured, the mechanical properties are greatly poor.

In addition, when the added neophenglycol exceeds 30 mol%, the flat coarse manufacturing process melted copolyester does not form a uniform shape when flowing out through the T-die, the stretching becomes uneven and the quality of the yarn becomes poor, 3 mol If it is less than%, moldability is poor.

In the present invention, the method for preparing the aliphatic copolyester is added to the monomer constituting the acid component and the diol component in a container that can be heated and stirred, followed by esterification or transesterification at a temperature of 220 ° C. or lower, followed by a temperature of 240 ° C. or higher. The polycondensation reaction is carried out at a high vacuum of 1 mmHg or less. At this time, as the condensation polymerization catalyst, a tin compound system or a titanium compound system was effective.

Examples of the tin compound include tin oxides such as tin oxide and tin oxide, halogen tin such as tin chloride, tin chloride, and tin sulfide, monobutyl tin oxide, dibutyl tin oxide, monobutyl hydroxy tin oxide, Organotin compounds such as dibutyltin dichloride, tetraphenyltin, and tetrabutyltin are included, and titanium-based compounds include tetrabutyl titanate, tetramethyl titanate, tetraisopropyl titanate, and tetra (2-ethylhexyl) titanium. Nate and the like can be used.

In addition, when necessary in synthesizing the aliphatic copolyester of the present invention, a heat stabilizer, a lubricant, a UV stabilizer, a colorant, and the like may be used. The heat stabilizer usable in the present invention may be a phosphorus compound, for example, phosphoric acid, monoethyl phosphate, trimethyl phosphate, tributyl phosphate, trioctyl phosphate, monophenyl phosphate, triphenyl phosphate and its derivatives, phosphorous acid, tri Phenyl phosphoric acid, trioctyl phosphoric acid, trimethyl phosphoric acid and its derivatives, Iganox 1010, Iganox 1222, Igafos 168, phenylphosphonic acid, etc. were especially excellent in phosphoric acid, trimethyl phosphoric acid, and triphenyl phosphoric acid. As the lubricant, calcium stearate, zinc stearate, barium stearate and the like can be used by adding a small amount. UV absorbers include p-phenyl-t-butylsalicylate, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4,5- It is possible to react by adding a small amount of trihydroxybutyl phenone and the like.

In order to manufacture a flat yarn using the aliphatic copolyester of the present invention, the melt extrusion is carried out at a temperature of 120 to 230 ° C. through a molding machine having a T die, and when the extrusion temperature exceeds 230 ° C., gelation and fish eye are used. Phenomenon occurs, resulting in poor product shape.

When a sheet is formed by melt extrusion through a T-die having a predetermined gap and width, the sheet is formed by cooling through air or water, and then the cooled and solidified sheet is cut to a certain thickness and then stretched. Stretching is caused by the difference in rotational speed between the rollers before and after the hot plate while passing through the heat plate heated by steam or the like. The stretching process is divided into two stages and is more efficient. In the first stage stretching, the cooled and solidified film is first heat-treated at a temperature of 60 to 90 占 폚 to perform 30 to 70 占 폚 stretching of the total stretching ratio. The two-step calculation is then performed at a temperature of 60 to 100 ° C. and then 30 to 70 ° C. of the total draw ratio. The roll is then rolled up to a certain length to complete the flat yarn product. At this time, it is also possible to appropriately adjust the physical properties of the flat yarn in accordance with the adjustment of the draw ratio.

Intrinsic viscosity (dl / g) of the copolyester of the present invention was measured by dissolving in orthochlorophenol solution at 35 ℃, the crystal melting point was analyzed using a differential calorimeter. Tensile strength was measured according to KS K323, and process workability and degradability were evaluated. Melt index was measured by applying a load of 2.16 kg at 190 ° C. according to ASTM D1238. The molecular weight of the aliphatic copolyester was analyzed by gel-to-chromatography and chromatography, and the solvent system used was a mixture of orthochlorophenol and chloroform 1: 4.

Hereinafter, the present invention will be described in detail through examples.

Example 1

125 kg (1,058.51 mol) of succinic acid, 16 kg (8.33 mol) of trimellitic anhydride, 117 kg (1,270.08 mol) of 1,4-butanediol, 2,2-dimethyl-1 as reaction monomers in a reactor equipped with a stirrer and a condenser 15 kg (144.02 mol) of, 3-propanediol were added thereto, and 50 g of tetrabutoxy titanate was added as a catalyst to raise the temperature in the reactor to 120 ° C. over 30 minutes from room temperature and to 220 ° C. over 120 minutes while stirring. It heated up temperature. At this time, the generated side reaction water was completely discharged through the condenser. Then, 170 g of tetrabutuxititanate was added as a catalyst and 30 g of phosphoric acid as a heat stabilizer, and the pressure in the tube was gradually reduced to 0.5 mmHg over 45 minutes, and the reaction was stirred for 180 minutes while raising the temperature of the tube to 245 ° C. After proceeding, the stirring was stopped and nitrogen was injected into the tube to pressurize and discharge the polymer to obtain a desired aliphatic copolyester. The color of the obtained aliphatic copolyester was slightly milky white, the melting point was 103.7 ° C, the number average molecular weight (Mn) was 52,000 won, the weight average molecular weight (Mw) was 296,000, and the melt index (190 ° C). , 21.6 kg) was 3.5 g / 10 min. The polyester obtained in pellet form was dried for 8 hours at 80 ° C. and melt-extruded through an extruder having a diameter of 90 mm and a L / d 25 with a T die having a width of 1200 m / m and a die spacing of 0.7 m / m. It was then cooled through a chill roller to form a sheet. The formed sheet was cut into a width of 7 m / m and passed through a hot plate to carry out two-step stretching. In the first stage drawing, 70% of the total drawing ratio was drawn at 65 ° C, and in the second stage drawing, the drawing was 30% of the total drawing ratio at a temperature of 85 ° C. The thickness of the resultant flat yarn was 3 mm in width and about 1000 deniers, and the tensile strength was 5.7 g / d. In addition, the obtained flat yarn was buried about 6 months in the ground, and about 63% was decomposed as a result of measuring the degree of decomposition by weight fraction.

Example 2

Except that the sheet obtained by melt extrusion and cooling the aliphatic copolyester during the flat yarn manufacturing process was cut to a width of 3m / m is the same as in Example 1 and the results are shown in Table 1.

Example 3

125 kg (1,058.51 mol) of succinic acid, 16 kg (8.33 mol) of trimellitic anhydride, 105 kg (1,139.82 mol) of 1,4-butanediol, 35 kg of 2,2-dimethyl-1,3-propanediol as reaction monomers 336.08 mole), except that an aliphatic copolyester was prepared in the same manner as in Example 1. In the flat yarn manufacturing process, 70% of the total draw ratio at 65 ° C. during the first step and 70 ° C. for the second step In the same manner as in Example 1 except that 30% of the total draw ratio was performed. The results are shown in Table 1.

Example 4

In the flat yarn manufacturing process, 60% of the total draw ratio at 65 ° C. during the first draw and 40% of the total draw ratio at the 70 ° C. were carried out in the same manner as in Example 1 except that 4.3 times of the total draw ratio was performed. It was made. The results are shown in Table 1.

Comparative Example 1

125 kg (1,058.51 mol) of succinic acid, 1.6 kg (8.33 mol) of trimellitic anhydride, 97 kg (1,052.97 mol) of 1,4-butanediol, 45 kg of 2,2-dimethyl-1,3-propanediol as reaction monomers 488.49 mole), except that the aliphatic copolyester is prepared in the same manner as in Example 1. In the flat yarn manufacturing process, 70% of the total draw ratio at 60 ° C. during the first step and 70 ° C. for the second step In the same manner as in Example 1 except that 30% of the total draw ratio was performed. The results are shown in Table 1.

Comparative Example 2

Except that 6.7 kg (34.87 moles) of trimellitic anhydride was added as a reaction monomer in the method for producing an aliphatic copolyester, it was the same as in Example 1, and the results are shown in Table 1.

Example 5

In Example 1, an aliphatic copolyester was synthesized using 74.9 kg (1,206.7 moles) of ethylene glycol instead of 1,4-butanediol as a reaction monomer, and in the flat yarn manufacturing process, single stage stretching was 75% of the total draw ratio at 65 ° C. In the two-stage drawing, it was the same as in Example 1 except that 25% of the total drawing ratio was performed at 87 ° C. The results are shown in Table 1.

Example 6

An aliphatic copolyester was synthesized in the same manner as in Example 1 except that 1.6 kg (8.33 mol) of citric acid was used instead of trimellitic anhydride as the reaction monomer. The results are shown in Table 1.

Claims (2)

Understanding the polycondensation reaction of aliphatic dicarboxylic acid and aliphatic diol In preparing an aliphatic polyester, a low molecular weight organic compound having three or more succinic acids or ester compounds thereof and three or more terminal carboxyl groups as an acid component, or 97 to 99.9 mol%, or Transesterification reaction using 0.1-3 mol% of its anhydrides, 70-97 mol% of 1 component selected from 1, 4- butanediol or ethylene glycol as a diol component, and 3-30 mol% of neopentyl glycol, and A method for producing a biodegradable flat yarn, characterized in that the aliphatic copolymer obtained by polycondensation is melted in an extruder, extruded through a T die, and uniaxially stretched. The method of claim 1, wherein the low molecular weight organic compound having three or more terminal carboxyl groups is trimellitic acid or trimellitic anhydride or 1,3,5-benzenetricarboxylic acid or citric acid. Manufacturing method.