阅读说明：本技术 一种用以转化成lpet的改性pet构成物及lpet的制备方法 (Modified PET (polyethylene terephthalate) composition for converting into LPET (Linear Low energy et) and preparation method of LPET ) 是由 张海涛 于汉青 朱闻宇 沈良华 于 2021-07-27 设计创作，主要内容包括：本发明公开一种用以转化成LPET的改性PET构成物,所述改性PET构成物包括以下质量份数的组分：聚对苯二甲酸乙二醇酯组合物80～99份；改性剂1～20份；金属盐添加剂0.01～0.05份；所述聚对苯二甲酸乙二醇酯组合物包括1～10wt％的二甘醇以及90～99wt％的聚对苯二甲酸乙二醇酯,所述聚对苯二甲酸乙二醇酯的酸阶在25～40meqKOH/kg；所述改性剂为C6-C10的二元酸、C5-C10二元醇中的一种或者多种。同时本发明还提供了该LPET的制备方法,主要包括第一中间体的生成、PET混合物的制备、第二中间体的生成以及叠加反应生成LPET。本发明获得的LPET熔点在210℃以下,且熔点与熔融软化点之差为15℃以内,提高了材料在加热时的热熔均匀性,并有效地提高了最终成型产品的尺寸稳定性。(The invention discloses a modified PET (polyethylene terephthalate) composition for converting into LPET (low power polyethylene terephthalate), which comprises the following components in parts by mass: 80-99 parts of a polyethylene terephthalate composition; 1-20 parts of a modifier; 0.01-0.05 part of metal salt additive; the polyethylene terephthalate composition comprises 1-10 wt% of diethylene glycol and 90-99 wt% of polyethylene terephthalate, and the acid level of the polyethylene terephthalate is 25-40 meqKOH/kg; the modifier is one or more of C6-C10 dibasic acid and C5-C10 dihydric alcohol. The invention also provides a preparation method of the LPET, which mainly comprises the steps of generating a first intermediate, preparing a PET mixture, generating a second intermediate and carrying out superposition reaction to generate the LPET. The melting point of the LPET obtained by the invention is below 210 ℃, and the difference between the melting point and the melting softening point is within 15 ℃, so that the hot melting uniformity of the material during heating is improved, and the dimensional stability of the final formed product is effectively improved.)

1. A modified PET composition for conversion into LPET, which comprises the following components in parts by mass:

80-99 parts of a polyethylene terephthalate composition;

1-20 parts of a modifier;

0.01-0.05 part of metal salt additive;

the polyethylene terephthalate composition comprises 1-10 wt% of diethylene glycol and 90-99 wt% of polyethylene terephthalate, and the acid level of the polyethylene terephthalate is 25-40 meqKOH/kg;

the modifier is one or more of C6-C10 dibasic acid and C5-C10 dihydric alcohol.

2. The modified PET formulation for conversion to LPET of claim 1 wherein the C6-C10 dibasic acid is: one or more of adipic acid, methylenesuccinic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and 2, 2-dimethylglutaric acid.

3. The modified PET formulation for conversion to LPET of claim 2 wherein the C5-C10 diol is: one or more of neopentyl glycol, 2-dimethyl-1, 3-propanediol, 1, 5-pentanediol, 1, 6-hexanediol and 2-methyl-1, 3-propanediol.

4. The modified PET construct for conversion to LPET of claim 1 wherein the metal salt additive comprises one or more of sodium carbonate, potassium carbonate, calcium carbonate, zinc carbonate, sodium acetate, zinc acetate, sodium benzoate.

5. The modified PET construct of claim 4 wherein the metal salt additive is one or more of sodium carbonate, sodium acetate, sodium benzoate.

6. The modified PET formulation for conversion to LPET of claim 1, comprising in parts by mass: 96-97 parts of a polyethylene terephthalate composition; 3-4 parts of a modifier; 0.02-0.03 part of metal salt additive.

7. A process for the preparation of an LPET according to any one of claims 1 to 6, comprising the steps of: a: preparing a polyethylene terephthalate composition and a C6-C10 diol, and conducting an alcoholysis reaction at a temperature of 140 ℃ to 210 ℃ for 1 to 3 hours, and then passing it through an inert gas to remove the diol to produce a first intermediate;

b: preparing a modifier to form a PET mixture with the first intermediate;

c: providing a metal salt additive and performing an esterification reaction with the PET mixture at a temperature of 240 ℃ to 250 ℃ for 1.3 to 2 hours to produce a second intermediate, and then performing a superposition reaction of the second intermediate at a temperature of 260 ℃ to 280 ℃ for 2 to 3 hours to produce LPET.

Technical Field

The invention relates to the technical field of synthetic fiber single (polymer) body manufacturing, in particular to a modified PET (polyethylene terephthalate) composition for converting into LPET (low density polyethylene terephthalate) and a preparation method of LPET.

Background

Generally, PET materials are limited by their high melting point characteristics (about 0.66g/dl) and their field of application is limited. PET materials are therefore typically modified to lower their melting point and are commonly referred to as LPETs. LPET refers to modified PET having a melting point in the range of 130 ℃ to 230 ℃, whereas unmodified PET materials typically have a melting point above 240 ℃.

The manufacturing method of the LPET is based on the production of common PET. Different LPET melts can be produced by adding a dibasic acid or glycol modifier in a proper proportion. The key point is the molecular structure ordering of the polyester molecular structure chain, the original regular molecular structure chain ordering in the melt is changed because the dibasic acid or the dihydric alcohol modifier is added into the copolymer to generate the mosaic prepolymer, and the originally higher melting point of the melt is reduced along with the damage of the molecular structure chain, so that the melting point of the prepolymer is reduced along with the increase of the addition amount of the modifier. For example, isophthalic acid (IPA), Adipic Acid (AA), or the like; or butanediol, hexanediol or neopentyl glycol (NPG), etc., which alter the original ordered molecular structure chain ordering in the melt and lower the melting point of the prepolymer.

In recent years, with the increasing awareness of environmental protection, the production and production methods of polyethylene terephthalate (PET) -related products have been modified, and commercial products made of recycled materials have become more and more popular. The physical or chemical properties of the recovered and regenerated commercial products at the present stage do not change any great extent, such as: the alcoholysis depolymerization process of the purchased polyester raw material and the low-alkyl aldehyde is simple, but does not improve the physical properties of the polymer, and additional raw materials are needed, such as: terephthalic acid (TPA) or dimethyl terephthalate (DMT).

Although prior references indicate that a portion of the alkaline earth metal salts and alkali metal salts have nucleating efficacy, not all of the alkali metal materials and alkali metal salts are effective as polyester nucleating agents. The prior art can rapidly crystallize polyester as a nucleating agent, such as: polyethylene terephthalate and polybutylene terephthalate, to which sodium-containing substances such as: sodium hydroxide solution, sodium benzoate and sodium o-chlorobenzoate, so that the acid tail end group COO-of the polyester and the alkaline earth metal positive ion generate a COO-Na form, and the nucleating agent can promote crystallization but cannot achieve the effect of reducing the melting point or melting and softening the difference of the threshold points.

If the difference between the melting point and the softening point of the polymer material cannot be controlled within a certain range, i.e., the difference between the melting point and the softening point is too large, or the softening point value is too low, it means that crystals or crystal nuclei in the polymer are small. The object already starts to melt before reaching the melting point. The polymer material is easy to cause uneven heating or overlong heating time of a part of structure in the production and heating processes, so that the dimensional stability of a formed product is poor, and even yellow color difference is generated on the appearance of the material.

These conventional techniques, as described above, reveal that LPET can be obtained by modifying the raw material, but still have a problem that the difference between the melting point and the softening point is too large, which limits the future processing without economic benefit. Raw materials are also prone to environmental issues. The above-mentioned concerns could be overcome if we could further develop an LPET made of modified PET that could achieve both low melting point and lower melting and softening point differentials.

Disclosure of Invention

The invention provides a modified PET composition for converting into LPET and a preparation method of LPET in order to avoid the defects of the prior art, the melting point range of the obtained LPET is between 180 and 220 ℃, and the difference between the melting point and the softening point is less than or equal to 15 ℃.

The technical scheme adopted by the invention for solving the technical problems is as follows: a modified PET composition for conversion into LPET, which comprises the following components in parts by mass: 80-99 parts of a polyethylene terephthalate composition; 1-20 parts of a modifier; 0.01-0.05 part of metal salt additive; the polyethylene terephthalate composition comprises 1-10 wt% of diethylene glycol and 90-99 wt% of polyethylene terephthalate, and the acid level of the polyethylene terephthalate is 25-40 meqKOH/kg; the modifier is one or more of C6-C10 dibasic acid and C5-C10 dihydric alcohol.

Further, the dibasic acid of C6-C10 is: one or more of adipic acid, methylenesuccinic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and 2, 2-dimethylglutaric acid.

Further, the C5-C10 dihydric alcohol is: one or more of neopentyl glycol, 2-dimethyl-1, 3-propanediol, 1, 5-pentanediol, 1, 6-hexanediol and 2-methyl-1, 3-propanediol.

Further, the metal salt additive comprises one or more of sodium carbonate, potassium carbonate, calcium carbonate, zinc carbonate, sodium acetate, zinc acetate and sodium benzoate.

Further, the metal salt additive is one or more of sodium carbonate, sodium acetate and sodium benzoate.

Further, the modified PET composition comprises the following components in parts by mass: 96-97 parts of a polyethylene terephthalate composition; 3-4 parts of a modifier; 0.02-0.03 part of metal salt additive.

The invention also provides a preparation method of the amphiphilic special material for cleaning the machine, which comprises the following steps: a: preparing a polyethylene terephthalate composition and a C6-C10 diol, and conducting an alcoholysis reaction at a temperature of 140 ℃ to 210 ℃ for 1 to 3 hours, and then passing it through an inert gas to remove the diol to produce a first intermediate; b: preparing a modifier to form a PET mixture with the first intermediate; c: providing a metal salt additive and performing an esterification reaction with the PET mixture at a temperature of 240 ℃ to 250 ℃ for 1.3 to 2 hours to produce a second intermediate, and then performing a superposition reaction of the second intermediate at a temperature of 260 ℃ to 280 ℃ for 2 to 3 hours to produce LPET.

The invention has the following beneficial effects: the low melting point LPET obtained by the invention can control the difference between the melting point and the softening point within a certain range, improves the hot melting uniformity of the material during heating, and effectively improves the dimensional stability of the final formed product.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.

Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention, and all other embodiments that can be obtained by one of ordinary skill in the art based on the embodiments of the present invention will fall within the scope of the invention as claimed.

The invention provides a modified PET (polyethylene terephthalate) composition for converting into LPET (low power polyethylene terephthalate), which comprises the following components in parts by mass: 80-99 parts of a polyethylene terephthalate composition; 1-20 parts of a modifier; 0.01-0.05 part of metal salt additive, wherein the polyethylene terephthalate composition comprises 1-10 wt% of diethylene glycol and 90-99 wt% of polyethylene terephthalate, the acid level of the polyethylene terephthalate is 25-40 meqKOH/kg, and the modifier is one or more of C6-C10 dibasic acid and C5-C10 dihydric alcohol.

Specifically, the dibasic acids of C6-C10 are: one or more of adipic acid, methylenesuccinic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and 2, 2-dimethylglutaric acid.

The dihydric alcohol C5-C10 is: one or more of neopentyl glycol, 2-dimethyl-1, 3-propanediol, 1, 5-pentanediol, 1, 6-hexanediol and 2-methyl-1, 3-propanediol.

The metal salt additive comprises one or more of sodium carbonate, potassium carbonate, calcium carbonate, zinc carbonate, sodium acetate, zinc acetate and sodium benzoate, and preferably one or more of sodium carbonate, sodium acetate and sodium benzoate.

Specifically, the modified PET composition comprises the following components in parts by weight: 96-97 parts of a polyethylene terephthalate composition; 3-4 parts of a modifier; 0.02-0.03 part of metal salt additive.

The preparation method of the LPET mainly comprises the following steps: preparing a polyethylene terephthalate composition and C6-C10 dihydric alcohol, carrying out alcoholysis reaction for 1 to 3 hours at the temperature of 140 to 210 ℃, and then passing the mixture through inert gas to remove the dihydric alcohol so as to generate a first intermediate; then preparing a modifier to form a PET mixture with the first intermediate; finally, a metal salt additive is prepared and esterified with the PET mixture at a temperature of 240 ℃ to 250 ℃ for 1.3 to 2 hours to form a second intermediate, and then the second intermediate is subjected to a superposition reaction at a temperature of 260 ℃ to 280 ℃ for 2 to 3 hours to form LPET.

The present invention will be further described with reference to the following specific examples.

Example 1

Preparing 80 kg of a polyethylene terephthalate composition comprising 0.8 kg of diethylene glycol and 79.2 kg of polyethylene terephthalate, the acid stage of the polyethylene terephthalate being 25meqKOH/kg, mixing 0.8 kg of adipic acid, conducting an alcoholysis reaction at 140 ℃ for 1 hour, then passing it through an inert gas, removing the glycols to produce a first intermediate, incorporating 0.2 kg of adipic acid to form a PET mixture, then adding 0.01 kg of sodium carbonate, conducting an esterification reaction at 240 ℃ for 1.3-2 hours to produce a second intermediate, and then conducting a stacking reaction at 260 ℃ for 2-3 hours to produce LPET. The melting point of the obtained LPET is 200 ℃, and the difference between the melting point and the melting softening point is 15 ℃.

Example 2

A96 kg polyethylene terephthalate composition comprising 0.96 kg of diethylene glycol and 95.04 kg of polyethylene terephthalate and having an acid stage of 25meqKOH/kg, 8 kg of adipic acid was mixed, subjected to an alcoholysis reaction at 140 ℃ for 1 hour, then passed through an inert gas to remove the glycols to form a first intermediate, 2 kg of adipic acid was incorporated to form a PET mixture, 0.01 kg of sodium carbonate was then added, and an esterification reaction was carried out at 240 ℃ for 1.3 to 2 hours to form a second intermediate, and then the second intermediate was subjected to a stacking reaction at 260 ℃ for 2 to 3 hours to form LPET was prepared. The melting point of the obtained LPET was 195 ℃ and the difference between the melting point and the melting softening point was 15 ℃.

Example 3

A96 kg polyethylene terephthalate composition comprising 4.8 kg of diethylene glycol and 91.2 kg of polyethylene terephthalate with an acid stage of 25meqKOH/kg, 8 kg of adipic acid mixed, alcoholysis at 140 ℃ for 1 hour, passing it through an inert gas to remove the glycols to form a first intermediate, incorporating 2 kg of adipic acid to form a PET mixture, adding 0.01 kg of sodium carbonate, esterification at 250 ℃ for 1.3-2 hours to form a second intermediate, and superposition at 270 ℃ for 2-3 hours to form LPET is prepared. The melting point of the obtained LPET is 180 ℃, and the difference between the melting point and the melting softening point is 13 ℃.

Example 4

A96 kg polyethylene terephthalate composition comprising 9.6 kg of diethylene glycol and 86.4 kg of polyethylene terephthalate with an acid stage of 25meqKOH/kg, 8 kg of adipic acid mixed therein, alcoholysis at 140 ℃ for 1 hour, passing it through an inert gas to remove the glycols to form a first intermediate, incorporating 2 kg of adipic acid to form a PET mixture, adding 0.01 kg of sodium carbonate, esterification at 250 ℃ for 1.3-2 hours to form a second intermediate, and superposition at 270 ℃ for 2-3 hours to form LPET is prepared. The melting point of the obtained LPET is 190 ℃ and the difference between the melting point and the melting softening point is 14 ℃.

Example 5

A96 kg polyethylene terephthalate composition comprising 4.8 kg of diethylene glycol and 91.2 kg of polyethylene terephthalate with an acid stage of 25meqKOH/kg, 8 kg of neopentyl glycol being mixed, alcoholysis being carried out at 140 ℃ for 1 hour, then passing it through an inert gas to remove the glycols to give a first intermediate, incorporating 2 kg of neopentyl glycol to give a PET mixture, then adding 0.01 kg of sodium carbonate, esterification being carried out at 250 ℃ for 1.3 to 2 hours to give a second intermediate, and then superposition at 270 ℃ for 2 to 3 hours to give LPET, is prepared. The melting point of the obtained LPET was 195 ℃ and the difference between the melting point and the melting softening point was 14 ℃.

Example 6

A96 kg polyethylene terephthalate composition comprising 4.8 kg of diethylene glycol and 91.2 kg of polyethylene terephthalate and having an acid stage of 25meqKOH/kg, 5 kg of neopentyl glycol were mixed and subjected to alcoholysis at 140 ℃ for 1 hour, then passed through an inert gas to remove the glycols to give a first intermediate, 5 kg of neopentyl glycol was incorporated to give a PET mixture, 0.01 kg of sodium carbonate was then added and esterification was carried out at 250 ℃ for 1.3 to 2 hours to give a second intermediate, and then the second intermediate was subjected to a stacking reaction at 270 ℃ for 2 to 3 hours to give LPET. The melting point of the obtained LPET was 200 ℃ and the difference between the melting point and the melting softening point was 14 ℃.

Example 7

Preparing 96 kg of a polyethylene terephthalate composition comprising 4.8 kg of diethylene glycol and 91.2 kg of polyethylene terephthalate, and the acid stage of the polyethylene terephthalate being 25meqKOH/kg, mixing 5 kg of neopentyl glycol, conducting an alcoholysis reaction at 140 ℃ for 1 hour, then passing it through an inert gas, removing the diol to produce a first intermediate, incorporating 5 kg of neopentyl glycol to form a PET mixture, then adding 0.01 kg of sodium carbonate and 0.01 kg of sodium acetate, conducting an esterification reaction at 250 ℃ for 1.3-2 hours to produce a second intermediate, and then conducting a superposition reaction at 270 ℃ for 2-3 hours to produce LPET. The melting point of the obtained LPET was 205 ℃ and the difference between the melting point and the melting softening point was 14 ℃.

Example 8

A96 kg polyethylene terephthalate composition comprising 4.8 kg of diethylene glycol and 91.2 kg of polyethylene terephthalate and having an acid stage of 25meqKOH/kg, 5 kg of neopentyl glycol were mixed and subjected to alcoholysis at 140 ℃ for 1 hour, then passed through an inert gas to remove the glycols to form a first intermediate, 5 kg of neopentyl glycol was incorporated to form a PET mixture, 0.02 kg of sodium benzoate was then added, esterification was carried out at 250 ℃ for 1.3 to 2 hours to form a second intermediate, and then the second intermediate was subjected to a stacking reaction at 270 ℃ for 2 to 3 hours to form LPET, was prepared. The melting point of the obtained LPET is 200 ℃, and the difference between the melting point and the melting softening point is 15 ℃.

From the above embodiments, it can be known that the melting point of the LPET provided by the present invention is below 210 ℃, and the difference between the melting point and the melting softening point is within 15 ℃, so that the hot melting uniformity of the material during heating is improved, and the dimensional stability of the final molded product is effectively improved.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All manner of description herein may be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

The present invention describes preferred embodiments, including the best mode known to the inventors for carrying out the invention. Of course, variations of these preferred embodiments will be apparent to those skilled in the art. The inventors envision that the variations may be used as appropriate by those skilled in the art and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications encompassed within the spirit and scope of the invention as defined by the claims. Moreover, any and all possible variations of the above-described elements are encompassed by the present invention unless otherwise indicated herein or otherwise clearly contradicted by context.