TWI492959B - A modified-polyester composition for making a low-melting copolyester and a method for making the low-melting copolyester - Google Patents

Description

Modified polyester composition and low melting point for forming low melting point copolyester Polyester production method

This invention relates to a modified polyester composition, and more particularly to a process for making a modified polyester composition for forming a low melting point copolyester and a low melting point copolyester.

Generally, polyester materials are limited by their high melting point characteristics, and their application fields are relatively limited. Therefore, polyester materials are usually modified to have a lower melting point, which is generally referred to as a low melting point polyester. The low melting point polyester refers to a modified polyester having a melting point ranging from 180 ° C to 230 ° C, and the unmodified polyester material usually has a melting point of 240 ° C or higher.

The conventional method for producing low-melting polyester is based on the production of ordinary polyester. The commonly used modification method is to add a proper ratio of dibasic acid and/or glycol modifier to produce different low melting point poly ester. Mainly because of the molecular arrangement of the polyester molecular chain, due to the addition of dibasic acid and / or glycol modifier to participate in the copolymerization to form a block copolymer, changing the original molecular chain In the column, the originally higher melting point decreases as the molecular chain is broken, so the melting point of the copolymer decreases as the amount of modifier added increases.

For example, a dibasic acid other than Terephthalic acid (TPA) such as isophthalic acid (IPA) or adipic acid (AA) may be added; or A glycol other than Ethylene glycol (EG), for example, 1,4-butanediol (1,4-BD), 1,6-hexanediol (1,6-hexamethylene diisocyanate , 1,6-HD) or neopentylene glycol (NPG).

In recent years, with the rise of environmental awareness, the manufacturing methods of polyethylene terephthalate (PET) related products have also changed, and the products made from recycled materials have become increasingly widespread. At present, there is no significant change in the physical properties of the recycled products. For example, U.S. Patent Nos. 4,758,502 and 6,191,177 disclose the process of the alcoholysis and depolymerization of recycled polyester materials and low alkyl alcohols, which is simple in process. However, the physical properties are not improved, and an additional virgin material such as Terephthalic acid (TPA) or Dimethyl Terephthalate (DMT) is required.

Although some literature has revealed that some alkali metal salts and alkaline earth metal salts have nucleation, not all alkali metal and alkaline earth metal salts can be used as high-efficiency polyester nucleating agents. U.S. Patent No. 4,380,621 discloses a fast crystalline polyester as a nucleating agent, such as poly(ethylene terephthalate) and poly(butylene terephthalate), which are added with sodium-containing species, For example: sodium hydroxide, sodium benzoate, and sodium o-chlorobenzoate, the acid end group COO ^{- of} the polyester forms a COO ^- Na ⁺ type with an alkali metal ion, but the nucleating agent can promote the crystallization effect, but cannot achieve a reduction. The effect of the difference between the melting point and the melt softening point.

If the difference between the melting point and the melt softening point of the polymer material cannot be controlled within a certain range, that is, the difference between the melting point and the melting softening point is too large, or the melting softening point is too low, indicating that the small crystal or crystal nucleus in the polymer is not reached. Melting has begun to occur at the temperature of the melting point. The use of such a polymer material in the production and heating process of the product is prone to occurrence of uneven heating, or partial structural heat, resulting in poor dimensional stability of the molded article, and even yellow discoloration of the appearance of the material.

Although the above-mentioned prior art discloses that a low melting point copolyester can be obtained by upgrading a raw material, there is still a problem that the difference between the melting point and the melting softening point is too large, so that the processing process is limited in the future, and the raw material is also caused. Environmental disputes. The above doubts can be overcome if a further development of a low melting point polyester using recycled polyester can achieve a low melting point and a lower difference between the melting point and the melt softening point.

Accordingly, one aspect of the present invention provides a modified polyester composition for forming a low melting point copolyester, the composition comprising a polyester mixture and a metal salt additive, and the polyester mixture comprising polyparaphenylene Ethylene formate composition and modifier. Among them, the polyethylene terephthalate composition contains 1 to 3 wt% of diethylene glycol, and the remaining component is polyethylene terephthalate (PET), and has 35 to 50 meq KOH/kg. The acid value is 80 to 99 wt% of the total weight of the polyester mixture. The modifier is a C6~C10 dibasic acid, a C5~C10 glycol or a group thereof. And it accounts for 1-20% by weight of the total weight of the polyester mixture. The metal salt additive is added in an amount of 0.002 to 0.03 parts by weight based on 100 parts by total of the total weight of the polyester mixture. The low melting point copolyester formed by the modified polyester composition has a melting point of not more than 230 ° C and a difference in melting point and melt softening point of not more than 15 ° C.

According to an embodiment of the invention, the dibasic acid of C6~C10 is one selected from the group consisting of adipic acid, pimelic acid, suberic acid, sebacic acid, sebacic acid, 2,2-di Methyl glutaric acid, methylene succinic acid, and combinations thereof. According to another embodiment of the present invention, the C5~C10 glycol is one selected from the group consisting of neopentyl glycol, 2,2-dimethyl-1,3-propanediol, 1,5-pentyl Glycol, 1,6-hexanediol, 2-methyl-1,3-propanediol, and combinations thereof.

According to another embodiment of the present invention, the metal salt additive is added in an amount of 0.005 to 0.01 parts by weight based on 100 parts by weight of the total weight of the polyester mixture, and is selected from the group consisting of sodium carbonate, Potassium carbonate, calcium carbonate, zinc carbonate, sodium acetate, zinc acetate, sodium benzoate, and combinations thereof. The metal salt additive is preferably sodium carbonate, sodium acetate or sodium benzoate or a combination thereof.

Another aspect of the present invention is to provide a method of producing a low melting point copolyester, the steps of which are as follows. Providing a polyethylene terephthalate composition and a C5~C10 glycol, performing an alcoholysis reaction at a temperature of 150 ° C to 200 ° C for 1.5 to 2.0 hours, and then removing the glycol by an inert gas To generate a first intermediate product. Next, a modifier is provided to form a polyester mixture with the first intermediate product, and a metal salt additive is provided, and the ester mixture is reacted with the polyester mixture at a temperature of 240 ° C to 250 ° C. 1.5 to 2.0 hours to generate a second intermediate product. Then, the second intermediate product is subjected to a superposition reaction at a temperature of 260 ° C to 280 ° C for 2 to 4 hours to form a low melting point copolyester. The above low melting point copolyester has a melting point of not more than 230 ° C, and the difference between the melting point and the melting softening point is not more than 15 ° C.

The above polyethylene terephthalate composition contains 1 to 3 wt% of diethylene glycol, and the remaining component is polyethylene terephthalate. According to an embodiment of the invention, the polyethylene terephthalate is formed, and some of the terephthalic acid is replaced by isophthalic acid, and the isophthalic acid accounts for the total weight of the polyethylene terephthalate composition. 1.5 to 2.5 wt%. According to an embodiment of the present invention, the metal salt additive is added in an amount of 0.002 to 0.03 part by weight based on 100 parts by total of the total weight of the polyester mixture. According to another embodiment of the present invention, the metal salt additive is added in an amount of 0.005 to 0.01 parts by weight based on 100 parts by total of the total weight of the polyester mixture. According to still another embodiment of the present invention, the metal salt additive is a group selected from the group consisting of sodium carbonate, potassium carbonate, calcium carbonate, zinc carbonate, sodium acetate, zinc acetate, sodium benzoate, and combinations thereof.

According to an embodiment of the invention, the modifier is a C6~C10 dibasic acid, a C5~C10 glycol or a combination thereof, and the modifier accounts for 1~20 wt% of the total weight of the polyester mixture. %. According to another embodiment of the present invention, the dibasic acid of C6~C10 is a group selected from the group consisting of adipic acid, pimelic acid, suberic acid, sebacic acid, sebacic acid, 2,2- Dimethylglutaric acid, methylene succinic acid, and combinations thereof. According to another embodiment of the present invention, the C5~C10 glycol is a group selected from the group consisting of neopentyl glycol, 2,2-dimethyl-1,3-propanediol, 1,5-pentane Glycol, 1,6-hexanediol, 2-methyl-1,3-propanediol, and combinations thereof.

According to the above, the low melting point copolyester produced by the method can control the difference between the melting point and the melting softening point within a certain range, improve the heat fusion uniformity of the material when heated, and effectively improve the dimensional stability of the final molded article. The low-melting point copolyester of the present invention can be used for spinning filaments, short-woven or non-woven fabrics, or further applied to construction materials, industrial materials, shoe materials, and the like.

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As described above, the conventional technique uses a raw material to prepare a low-melting point copolyester. Although the melting point can be lowered, there is still a problem that the difference between the melting point and the melt softening point is too large, and excessive use of raw materials may cause environmental problems.

Accordingly, there is provided a modified polyester composition for forming a low melting point copolyester, the composition comprising a polyester mixture and a metal salt additive, the polyester mixture comprising at least a polyethylene terephthalate composition and A modifier. The above polyethylene terephthalate composition accounts for 80 to 99% by weight of the total weight of the polyester mixture, and its acid value is 35 to 50 meq KOH/kg. The polyethylene terephthalate composition contains 1 to 3 wt% of diethylene glycol, and the remaining component is polyethylene terephthalate (PET), and the poly The source of ethylene terephthalate can be any pipe produced from polyethylene terephthalate, such as a PET bottle or clothing.

The modifier is a C6~C10 dibasic acid, a C5~C10 glycol or a combination thereof, and the modifier accounts for 1-20% by weight of the total weight of the polyester mixture. In one embodiment, the C6-C10 dibasic acid is one selected from the group consisting of adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 2,2-dimethyl Glutaric acid, methylene succinic acid, and combinations thereof. In another embodiment, the C5-C10 glycol is one selected from the group consisting of neopentyl glycol, 2,2-dimethyl-1,3-propanediol, 1,5-pentane Alcohol, 1,6-hexanediol, 2-methyl-1,3-propanediol, and combinations thereof.

The metal salt additive is added in an amount of 0.002 to 0.03 parts by weight based on 100 parts by total of the total weight of the polyester mixture. In another embodiment, the metal salt additive is added in an amount of 0.005 to 0.01 parts by weight based on 100 parts by total of the total weight of the polyester mixture. In one embodiment, the metal salt is one selected from the group consisting of sodium carbonate, potassium carbonate, calcium carbonate, zinc carbonate, sodium acetate, zinc acetate, sodium benzoate, and combinations thereof. In another embodiment, the metal salt is a monosodium salt such as sodium carbonate, sodium acetate or sodium benzoate or a combination thereof.

The polyethylene terephthalate composition contains at least polyethylene terephthalate obtained by polymerizing terephthalic acid and ethylene glycol. In one embodiment, the polyethylene terephthalate is obtained by granulating a recycled bottle piece, wherein part of the terephthalic acid is replaced by isophthalic acid, and the isophthalic acid accounts for polyterephthalic acid. The total weight of the ethylene diester composition is 1.5 to 2.5 wt%, and the isophthalic acid helps to change the crystallinity of the polyethylene terephthalate. Low its melting point. In another embodiment, the polyethylene terephthalate composition has an acid value of 35 to 50 meq KOH/kg, preferably 40 to 50 meq KOH/kg, more preferably 45 to 50 meq KOH/kg. . In the process of recovering the polyethylene terephthalate bottle into an ester granule, the acid value is higher than that of the general polyethylene terephthalate because of thermal cracking, and no granulation is added. The diol, so the content of diethylene glycol will be relatively low, therefore, the effect of the metal salt additive is more significant, and the difference between the melting point and the melting softening point can be reduced.

The low melting point copolyester of the embodiment of the invention has a melting point of not more than 230 ° C, and the difference between the melting point and the melting softening point is not more than 15 ° C, which helps to increase the temperature range that can be tolerated in the future processing. It can also be used to make a variety of different fabrics, such as filaments, short woven or non-woven fabrics.

The present invention also provides a method of producing the above low melting point copolyester, the steps of which comprise the following. First, a polyethylene terephthalate composition and a C5~C10 glycol are provided, and the alcoholysis reaction is carried out at a temperature of 150 ° C to 200 ° C for 1.5 to 2.0 hours, followed by inert gas shift. In addition to the glycol to form a first intermediate product, the above polyethylene terephthalate composition contains 1 to 3 wt% of diethylene glycol, and the remaining component is polyethylene terephthalate. A modifier is then provided with the first intermediate to form a polyester mixture, and a metal salt additive is provided for esterification with the polyester mixture to form a second intermediate. Next, a catalyst and a stabilizer are provided to promote the second intermediate product to undergo a recombination reaction to form a low melting point copolyester.

In another embodiment, the diol which is subjected to alcoholysis reaction with polyethylene terephthalate is a C5-C10 diol, which may be linear or branched. An aliphatic diol, preferably ethylene glycol. Here, the addition of a trace amount of glycol to the alcoholysis reaction is to recover the ester particles in the melting process to cut the molecular chain to form a lower molecular weight form, to re-link in the case of the coincidence reaction, and does not affect the low melting point of the present invention. Polyester does not add raw materials (eg TPA, IPA, etc.).

The metal salt additive can be used as a crystallization accelerator to increase the melt softening point, but has no significant effect on the melting point, and thus can narrow the difference between the melting point and the melt softening point. In one embodiment, the metal salt additive is added in an amount of 0.002 to 0.03 parts by weight based on 100 parts by total of the total weight of the polyester mixture. In another embodiment, the metal salt additive is added in an amount of 0.005 to 0.01 parts by weight based on 100 parts by total of the total weight of the polyester mixture. The specific embodiments and features of the metal salts of the present embodiment can be the same as those of the above-described embodiments.

The modifier is a C6~C10 dibasic acid, a C5~C10 glycol or a combination thereof, and the modifier accounts for 1-20% by weight of the total weight of the polyester mixture. The specific embodiments and characteristics of the C6 to C10 dibasic acid and the C5 to C10 glycol of the present embodiment can be the same as those of the above embodiment. The melting point of the copolyester can be adjusted by different modifiers. In one embodiment, the addition of adipic acid as a modifier can reduce the melting point of the copolyester from about 240 ° C to less than 230 ° C.

When the superposition reaction is carried out, a catalyst and a stabilizer may be further provided. In one embodiment, the catalyst includes, but is not limited to, a cerium-containing compound, a cerium-containing compound, a tin-containing compound, a titanium-containing compound, a gallium-containing compound, and an aluminum-containing compound. Preferred is antimony trioxide (antimony (III) oxide, Sb2O3), the catalyst has the function of accelerating the coincidence reaction. In another embodiment, the stabilizer is a polyol including, but not limited to, glycerol, trimethylolpropane, and pentaerythritol, preferably trimethylolpropane, which is reactive with the acid groups produced during the recombination reaction. , with thermal stability.

The detailed description of the present invention and the test results are set forth below for the purpose of illustration and description. The embodiments disclosed below may be combined or substituted with each other in an advantageous situation, and other embodiments may be added to an embodiment without further description or description, and any familiar knowledge of the art is common. Modifications and variations that can be readily made by those skilled in the art are intended to be included within the scope of the invention.

Preparation of low melting point polyester <Chemicals and Instruments>

1. Terephthalic acid (TPA): purchased from Yadong Petrochemical Company.

2. Isophthalic acid (IPA): purchased from Mitsubishi Chemical Corporation.

3. Ethylene glycol (EG): purchased from Donglian Chemical Company.

4. Recycling bottle granulation-poly(p-phenylene terephthalate) (recycled PET): The source is Far East New Century Co., Ltd., manufactured by model CFF-291R, melting point is 240 ° C, and isophthalic acid (IPA) content is 1.5. Wt%, diethylene glycol (DEG) content is 2.0~2.5wt%, acid value is 35~50 meq KOH/kg.

5. Trimethylolpropane (TMP): purchased from Aldrich, with a purity of 99.9%.

6. Antimony trioxide: purchased from Aldrich, with a purity of 99.999%.

7. Differential scanning calorimeter (DSC): manufactured by TA Instruments, USA, model DSC-Q2000.

<Analysis test> 1. Measuring melting point (Tm) and melting softening point (onset)

The modified polyester composition is made into polyester ester granules. The melting point (Tm) and melting softening point (onset) of the polyester ester particles were measured by a thermal differential scanner (DSC).

The measurement method is based on the operation manual of the DSC: the first heating section is heated to 300 ° C at a rate of 10 ° C per minute, the first cooling section is cooled to 30 ° C at 10 ° C per minute; the second heating section is 10 per minute. The temperature was raised at °C, and the melting point (Tm) and melting softening point (onset) were measured. 1 is a schematic diagram of a DSC curve of a low melting point copolyester according to an embodiment of the present invention as measured by DSC. As shown, the difference between the melting point (Tm) and the onset softening point is ΔT.

2. Measuring acid value

Place the sample to be tested (2~4g) in a bottle of 50ml phenol and tetrachloroethane mixture, heat to completely dissolve, add 6~8 drops of bromophenol blue indicator to the cooled solution, to 0.1N Potassium hydroxide (KOH) / benzyl alcohol standard solution Titration, the color change of the solution changes from yellow to yellowish green, then to blue, which is the end point of the titration.

Acid value (meq KOH/kg) = [sample solution titration amount (ml) - blank solution titration amount (ml)] * N * 1000 / sample weight (g)

Where N = equivalent concentration of potassium hydroxide-benzyl alcohol solution

3. Measurement of diethylene glycol (DEG) content

The diethylene glycol content of the sample was measured by a gas chromatograph. Firstly, the polyester ester granules were respectively added to 1,4-butanediol and dissolved in potassium hydroxide/n-propanol, and then an appropriate amount of 1.6N hydrogen chloride was added and stirred uniformly. The clarified liquid was partially injected into the gas chromatograph to test the gan Alcohol concentration.

Comparative example A1

Take 30.26 kg of terephthalic acid (TPA) and 14.12 kg of ethylene glycol (EG), and the esterification reaction end temperature is 250 °C. After the esterification reaction is completed, the catalyst antimony trioxide and the heat stabilizer trimethylolpropane are added to carry out the superposition reaction, and the final reaction temperature is 280 ° C, the final reaction time is 7 hours, and the acid value of the above ester particles is measured to be 31 meq. KOH/kg, diethylene glycol content of 3.5%. The ester granules are subjected to an alcoholysis reaction, and the alcoholysis reaction is carried out in an amount of 5.6 kg of ethylene glycol. The ethylene glycol is removed by an inert gas, and the esterification reaction is carried out with 7 g of sodium carbonate (0.02 part by weight) of a metal salt additive. The esterification reaction end temperature was 250 °C. After completion of the esterification reaction, a catalyst of antimony trioxide and a heat stabilizer, trimethylolpropane, were added to carry out a recombination reaction, and the final reaction temperature was 280 ° C, and the final reaction time was 7 hours. After that, the melting point of the DSC amount At 245 ° C, the melt softening point is 226 ° C, the difference between the melting point and the melt softening point is 19 ° C, and the acid value is 28 meq KOH / kg.

Comparative example A2

Take 35 kg (100 wt%) of recycled PET ester type (CFF-291R), mix with 5.6 kg of ethylene glycol for alcoholysis reaction, remove ethylene glycol with inert gas, and add 7 g of sodium carbonate (0.02 wt The esterification reaction was carried out as a metal salt additive, and the esterification reaction end temperature was 250 °C. After the esterification reaction is completed, the catalyst antimony trioxide and the thermal stabilizer TMP are added to carry out the superposition reaction, and the final reaction temperature is 280 ° C, the final reaction time is 7 hours, and the acid value of the above ester particles is measured to be 47 meq KOH / kg. The diethylene glycol content was 2.5 wt%. Thereafter, the melting point of the DSC amount was 239 ° C, the melting softening point was 225 ° C, the difference between the melting point and the melt softening point was 14 ° C, and the acid value was 38 meq KOH / kg.

Comparative Example A3

The operating conditions were approximately the same as in Comparative Example A2 except that no metal salt additive was added during the preparation. The obtained low melting point polyester had a melting point of 238 ° C, a melting softening point of 219 ° C, a difference between the melting point and the melt softening point of 19 ° C, and an acid value of 45 meq KOH / kg.

As can be seen from the above Table 1, Comparative Example A1 uses a raw material terephthalic acid to prepare a low melting point polyester having a melting point higher than 230 ° C, and the difference between the melting point and the melt softening point cannot reach 15 ° C; and Comparative Example A2 uses recycled PET. And the additive sodium carbonate, but the combination of no modifier added can narrow the difference between the melting point and the melt softening point to within 15 ° C, but the melting point temperature is still higher than 230 ° C; Comparative Example A3 uses recycled PET, no additives And a modifier having a melting point higher than 230 ° C, and the difference between the melting point and the melting softening point is greater than 15 ° C.

The main reason for the above results is that the polyester acid in the comparative example A1 has a lower polyester acid value (31 meq KOH/kg) and a higher diethylene glycol content (3.5 wt%). In the alcoholysis process, the sodium ion is not It is easy to form COO ^- Na ⁺ type, and the content of COO ^- Na ^{+ is} small, so that the melting softening point is not easy to move to the high temperature direction. The high diethylene glycol content also interferes with the opportunity of sodium ion substitution to form COO ^- Na ⁺ , so the melting point and melt softening The difference between the points is greater than 15 °C. In Comparative Example A2, the acid value before the polyester reaction was higher, and the diethylene glycol content was lower (47 meq/kg, 2.5 wt%). During the alcoholysis process, the sodium ion easily formed the COO ^- Na ⁺ type and the COO ^- Na ⁺ content was high. The melt softening point is moved to a high temperature direction, and the diethylene glycol content is low, so that the chance of interfering with sodium ion substitution to form COO ^- Na ⁺ is small, so the difference between the melting point and the melting softening point may be not more than 15 °C.

However, none of the products of the above comparative examples could simultaneously reach a melting point of not more than 220 ° C, and the difference between the melting point and the melting softening point was more than 15 ° C.

Example B1

Take 33.95 kg (97 wt%) of recovered PET ester granules (model CFF-291R) with an alcoholysis reaction of 5.6 kg of ethylene glycol, remove ethylene glycol with an inert gas, and 1.05 kg of adipic acid ( 3 wt%) and 7 g of sodium carbonate (0.02 parts by weight) of a metal salt additive were subjected to an esterification reaction, and the esterification reaction end temperature was 250 °C. After the esterification reaction was completed, the catalyst antimony trioxide and the heat stabilizer TMP were added to carry out the superposition reaction, and the final reaction temperature was 280 ° C, and the final reaction time was 7 hours. Thereafter, a melting point analysis test was performed using a differential scanning calorimeter (DSC).

Example B2~B5

The operating conditions were approximately the same as in Example B1 except that different levels of adipic acid were changed and the recovered PET content was adjusted as a function of adipic acid content.

It can be seen from the above Table 2 that different amounts of the modifier adipic acid can lower the melting point of the polyester, and the larger the amount of the modifier is, the more obvious the decreasing tendency of the melting point; in addition, the modifier is added The acid and the additive sodium carbonate can not only make the difference between the melting point and the melting softening point fall within 15 ° C, but also control the melting point to not more than 230 ° C. The difference in acid value between before and after the reaction of Examples B1 to B5 is more than 5, and it can be seen that if the initial polyester acid value of the reaction is greater than 45 meq KOH/kg, the added additive is more likely to form a COO ^- Na ⁺ type, which is effective. The difference between the melting point and the melt softening point is controlled.

In addition, compared with the above comparative examples, the modified polyester composition needs to contain recycled PET, additives and modifiers in order to simultaneously achieve the formation of low melting. The low melting point polyester having a melting point of the polyester of not more than 230 ° C and a difference between the melting point and the melting softening point of not more than 15 ° C.

Example B6~B9

The operating conditions were substantially the same as in Example B1 except that the modifier adipic acid was changed to different levels of neopentyl glycol, and the recovered PET content was adjusted as the neopentyl glycol content was changed.

It can be seen from the above Table 3 that the addition of different amounts of the modifier, neopentyl glycol, can lower the melting point of the polyester, and the larger the amount of the modifier added, the more obvious the tendency of the melting point to fall; in addition, the modifier is added. Neopentyl glycol and the additive sodium carbonate can make the difference between the melting point and the melting softening point fall within 15 ° C, and the melting point can be controlled to not more than 230 ° C.

Example B10~12

The operating conditions were substantially the same as in Example B1 except that the modified agent adipic acid was present in a different amount of 2-methyl-1,3-propanediol, and the recovered PET content was adjusted as the modifier content was changed.

It can be seen from the above Table 4 that by adding different amounts of the modifier 2-methyl-1,3-propanediol, the melting point of the polyester can be lowered, and the larger the amount of the modifier added, the more obvious the decreasing tendency of the melting point; In addition, the addition of the modifier 2-methyl-1,3-propanediol and the additive sodium carbonate can make the difference between the melting point and the melt softening point fall within 15 ° C, and the melting point can be controlled to not more than 230 ° C.

Example B13~15

The operating conditions were substantially the same as in Example B1 except that different kinds of metal salt additives were changed.

As can be seen from the above Table 5, in the case where the melting point is not more than 230 ° C, different kinds of metal salt additives can narrow the difference between the melting point and the melt softening point to within 15 ° C.

Example B16~19

The operating conditions were substantially the same as in Example B1 except that different levels of metal salt additives were changed.

It can be seen from the above Table 6 that when the melting point is not more than 230 ° C, the addition of different amounts of the metal salt additive can narrow the gap between the melting point and the melt softening point. According to an embodiment of the present invention, the amount of sodium carbonate added is not more than 0.03 parts by weight to reduce the raw material cost.

Comparative example C1

Referring to the preparation method of Comparative Example A1, 34.58 kg of terephthalic acid and 16.14 kg of ethylene glycol were used, and the molar ratio of the alkyd was 1.25, and the end temperature of the esterification reaction was 250 °C. After the esterification reaction is completed, the catalyst antimony trioxide and the heat stabilizer TMP are added to carry out the recombination reaction, and the final reaction temperature is 280 ° C, the final reaction time is 7 hours, and the acid value of the above ester particles is measured to be 30 meq KOH/kg. The diethylene glycol content was 3.5% by weight. The ester granules are further subjected to an alcoholysis reaction, and ethylene glycol is removed by an inert gas, and the end temperature of the esterification reaction is 250 °C. After completion of the esterification reaction, a catalyst of antimony trioxide and a heat stabilizer, trimethylolpropane, were added to carry out a recombination reaction, and the final reaction temperature was 280 ° C, and the final reaction time was 7 hours. Thereafter, a melting point analysis test was performed using a differential scanning calorimeter (DSC).

Comparative example C2

Referring to the preparation method of Comparative Example C1, 32.73 kg of terephthalic acid, 1.53 kg of adipic acid, 0.76 kg of isophthalic acid, and 16.14 kg of ethylene glycol were used, and the molar ratio of the alkyd was 1.25, and the end temperature of the esterification reaction was 250 ° C. After the esterification reaction is completed, the catalyst antimony trioxide and the heat stabilizer trimethylolpropane are added to carry out the recombination reaction, and the final reaction temperature is 280 ° C, the final reaction time is 7 hours, and the acid value of the above ester particles is measured to be 30 meq. KOH/kg, diethylene glycol content was 3.6 wt%. The ester granules are subjected to an alcoholysis reaction, and an alcoholysis reaction is carried out in an amount of 5.6 kg of ethylene glycol. The ethylene glycol is removed by an inert gas, and 1.53 kg of adipic acid and 8 g of sodium carbonate (0.02 parts by weight) of metal are further added. The salt additive is subjected to an esterification reaction, and the esterification reaction end temperature is 250 °C. After the esterification reaction was completed, the catalyst antimony trioxide and the heat stabilizer TMP were added to carry out the superposition reaction, and the final reaction temperature was 280 ° C, and the final reaction time was 7 hours.

Comparative Example C3

Referring to the preparation method of the comparative example of C1, 34 kg of terephthalic acid, 0.51 kg of isophthalic acid, and 16.14 kg of ethylene glycol were used, and the molar ratio of the alkyd was 1.25, and the end temperature of the esterification reaction was 250 °C. After the esterification reaction is completed, the catalyst antimony trioxide and the heat stabilizer trimethylolpropane are added to carry out the recombination reaction, and the final reaction temperature is 280 ° C, the final reaction time is 7 hours, and the acid value of the above ester particles is measured to be 30 meq. KOH/kg, diethylene glycol content was 3.6 wt%. The ester granules are subjected to an alcoholysis reaction, and an alcoholysis reaction is carried out in an amount of 5.6 kg of ethylene glycol. The ethylene glycol is removed by an inert gas, and an esterification reaction is carried out with 8 g of sodium carbonate (0.02 part by weight) of a metal salt additive. The esterification reaction end temperature was 250 °C. After the esterification reaction was completed, the catalyst antimony trioxide and the heat stabilizer TMP were added to carry out the superposition reaction, and the final reaction temperature was 280 ° C, and the final reaction time was 7 hours.

Comparative example C4

Referring to the preparation method of the C1 comparative example, 32.73 kg of terephthalic acid, 0.76 kg of isophthalic acid, 16.14 kg of ethylene glycol, and an alcoholic acid molar ratio of 1.25 were used for esterification reaction, and the esterification reaction end temperature was 250. °C. After the esterification reaction is completed, the catalyst antimony trioxide and the thermal stabilizer TMP are added to carry out the recombination reaction, and the final reaction temperature is 280 ° C, and the final reaction time is obtained. It was 7 hours, and the acid value of the above ester particles was measured to be 29 meq KOH/kg, and the diethylene glycol content was 3.5 wt%. The ester granules are subjected to an alcoholysis reaction, and an alcoholysis reaction is carried out in an amount of 5.6 kg of ethylene glycol. The ethylene glycol is removed by an inert gas, and an esterification reaction is carried out with 1.53 kg of adipic acid. The esterification reaction temperature is 250. °C. After completion of the esterification reaction, a catalyst of antimony trioxide and a heat stabilizer, trimethylolpropane, were added to carry out a recombination reaction, and the final reaction temperature was 280 ° C, and the final reaction time was 7 hours.

It can be seen from the above Table 7 that the melting point and melting of the low melting point copolyester are prepared by using the raw material terephthalic acid adding modifier or metal salt additive. The difference in melting softening point is above 15 ° C, and it is impossible to reach the melting point below 230 ° C at the same time. Further, in Comparative Example C4, the difference between the melting point and the melt softening point was more remarkable in the case where the metal salt-based additive was not added.

According to the embodiment of the present invention, the modified polyester of the present invention is made of a green material of recycled polyester (no need to add raw materials), and the low melting point obtained after adding the modifier and the metal salt additive Compared with ethylene terephthalate made from terephthalic acid and ethylene glycol, the melting point of ester can reach 20~30 °C, which can solve the melting point and melting softening point of thermal properties. The disadvantage of the difference is too large. Since the recovered polyethylene terephthalate is modified by the present invention, the melting point can be lowered to below 230 ° C, and the difference between the melting point and the melting softening point can be limited, so that the product is more susceptible to heat during processing in the future. Uniform and completely melted, which improves the dimensional stability of the product and reduces the appearance of defects. In addition, the low-melting polyester has good spinnability, low production cost and high productivity, and can be widely used for spinning filaments, short-woven or non-woven fabrics, or further applied to building materials, industrial materials, shoe materials, etc. Use, with good economic benefits.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and the present invention can be modified and modified without departing from the spirit and scope of the present invention. The scope is subject to the definition of the scope of the patent application attached.

Claims (18)

A modified polyester composition for preparing a low melting point copolyester, comprising: a polyester mixture comprising: a polyethylene terephthalate composition comprising 1 to 3 wt% of diethylene glycol, and the balance The composition is polyethylene terephthalate, the polyethylene terephthalate composition has an acid value of 35 to 50 meq KOH / kg, and accounts for 80 to 99 wt% of the total weight of the polyester mixture; a granule, which is a C6-C10 dibasic acid, a C5-C10 diol or a combination thereof, and comprises 1 to 20% by weight based on the total weight of the polyester mixture; and a metal salt additive, The total weight of the polyester mixture is 100 parts by weight, and the addition amount is 0.002 to 0.03 parts by weight, wherein the low melting point copolyester has a melting point of not more than 230 ° C, and the difference between the melting point and the melting softening point is not more than 15 °C. The modified polyester composition according to claim 1, wherein the C6-C10 dibasic acid is one selected from the group consisting of adipic acid, pimelic acid, suberic acid, and anthracene. Diacid, sebacic acid, 2,2-dimethylglutaric acid, methylene succinic acid, and combinations thereof. The modified polyester composition according to claim 1, wherein the C5 to C10 glycol is one selected from the group consisting of neopentyl glycol and 2,2-dimethyl- 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, and combinations thereof. The modified polyester composition of claim 1, wherein the metal salt is added The agent is one selected from the group consisting of sodium carbonate, potassium carbonate, calcium carbonate, zinc carbonate, sodium acetate, zinc acetate, sodium benzoate, and combinations thereof. The modified polyester composition of claim 4, wherein the metal salt additive is sodium carbonate, sodium acetate, sodium benzoate or a combination thereof. The modified polyester composition according to claim 1, wherein the metal salt additive is added in an amount of 0.005 to 0.01 parts by weight based on 100 parts by weight of the total of the polyester mixture. The modified polyester composition according to claim 1, wherein the polyethylene terephthalate is formed, a part of terephthalic acid is substituted by isophthalic acid, and isophthalic acid accounts for the pair The total weight of the ethylene phthalate composition is from 1.5 to 2.5% by weight. The modified polyester composition of claim 1, wherein the low melting point copolyester is used for spinning a filament, a short woven or a non-woven fabric. A method for preparing a low melting point copolyester, the method comprising the steps of: providing a polyethylene terephthalate composition and a C5~C10 glycol, and performing the alcoholysis reaction at a temperature of 150 ° C to 200 ° C After 1.5 to 2.0 hours, the diol is removed by an inert gas to form a first intermediate product, wherein the polyethylene terephthalate composition comprises 1 to 3 wt% of diethylene glycol, and the remaining components are poly Ethylene terephthalate; providing a modifier to form a polyester mixture with the first intermediate; providing a metal salt additive, and esterifying the polyester mixture at a temperature between 240 ° C and 250 ° C The reaction is 1.5 to 2.0 hours to form a second intermediate product; The second intermediate product is subjected to a superposition reaction at a temperature of 260 ° C to 280 ° C for 2 to 4 hours to form the low melting point copolyester, wherein the low melting point copolyester has a melting point of not more than 230 ° C, and The difference between the melting point and the melt softening point is not more than 15 °C. The method according to claim 9, wherein the metal salt additive is added in an amount of 0.002 to 0.03 part by weight based on 100 parts by total of the total weight of the polyester mixture. The method of claim 10, wherein the metal salt additive is added in an amount of 0.005 to 0.01 parts by weight based on 100 parts by weight of the total of the polyester mixture. The method of claim 9, wherein the modifier is a C6-C10 dibasic acid, a C5-C10 glycol or a combination thereof, and the modifier accounts for the total weight of the polyester mixture. 1~20wt%. The method of claim 12, wherein the C6-C10 dibasic acid is one selected from the group consisting of adipic acid, pimelic acid, suberic acid, azelaic acid, and azelaic acid. Acid, 2,2-dimethylglutaric acid, methylene succinic acid, and combinations thereof. The method of claim 12, wherein the C5-C10 glycol is one of the group consisting of neopentyl glycol, 2,2-dimethyl-1,3-propanediol 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, and combinations thereof. The method of claim 9, wherein the metal salt additive is one selected from the group consisting of sodium carbonate, potassium carbonate, calcium carbonate, and carbonic acid. Zinc, sodium acetate, zinc acetate, sodium benzoate and combinations thereof. The method of claim 15, wherein the metal salt additive is sodium carbonate, sodium acetate or sodium benzoate. The method of claim 9, wherein the polyethylene terephthalate is formed, the partial terephthalic acid is replaced by isophthalic acid, and the isophthalic acid accounts for the polyethylene terephthalate. The total weight of the ester composition is from 1.5 to 2.5% by weight. The method of claim 9, wherein the low melting point copolyester is used for spinning filaments, short woven or non-woven fabrics.