WO2020156346A1

WO2020156346A1 - Hydrolyzable copolyester, preparation method therefor, and application thereof

Info

Publication number: WO2020156346A1
Application number: PCT/CN2020/073349
Authority: WO
Inventors: 王格侠; 季君晖; 黄丹
Original assignee: 中国科学院理化技术研究所
Priority date: 2019-01-29
Filing date: 2020-01-21
Publication date: 2020-08-06
Also published as: CN109762143A

Abstract

Disclosed is a hydrolyzable copolyester. The molecular segment of the copolyester contains a segment of a difficultly hydrolyzable polyester and a segment of an easily hydrolyzable polyester, and the copolyester is a random copolymer or block copolymer composed of the segment of the difficultly hydrolyzable polyester and the segment of the easily hydrolyzable polyester. The copolyester has good strength and toughness, is biodegradable, and can degrade quickly when placed in a natural water environment. Further disclosed is a preparation method for the copolyester, and an application thereof.

Description

Hydrolyzable copolyester and its preparation method and application

Technical field

The invention relates to the field of degradable polymer materials. More specifically, it relates to a hydrolyzable copolyester and its preparation method and application.

Background technique

Biodegradable plastics are a type of aliphatic polyester or copolyester. Not only has general-purpose plastics comparable thermal and mechanical properties and processing properties, compared with olefin and amide polymer materials, its ester bond is more likely to be broken by the action of water, oxygen, and microorganisms, and has special biodegradability. Microbial enzymatic degradation can occur in compost or in the soil for several months, and it can be completely decomposed into CO ₂ and water. After more than 20 years of development, from the first generation of hydroxyalkanoates (PHAs) to the second generation of polylactic acid (PLA), to the third generation of polybutylene succinate (PBS) and its copolymers Phthalate succinic acid copolyester (PBAT), biodegradable plastics have been successfully commercialized, and their production, modification, and application technologies have become more mature, and their costs have gradually decreased, approaching the production costs of ordinary plastics. It has been gradually used in many fields. Start to replace general-purpose plastics. With the increasing awareness of global environmental protection and the gradual introduction of "plastic bans" in various countries, the biodegradable plastics industry chain has continued to grow and develop. As of 2017, an annual production capacity of 879,000 tons has been formed.

The nature of the biodegradation of polyester is the enzymatic hydrolysis of ester bonds. This process is affected by many factors such as the type and quantity of specific microorganisms in the environment, water, temperature and pH, among which the type and quantity of microorganisms in the natural environment are the most critical factors affecting the degradation rate. Without the action of microorganisms, the polyester can only undergo self-hydrolysis, and the degradation rate is drastically reduced. Because the environmental factors in natural water bodies, especially seawater, are very different from those in soil and compost environment, especially the temperature in seawater, the species and quantity of specific microorganisms are significantly lower than those in soil and compost. The existing commercial biodegradable polyester is in natural The degradation in water bodies is often slow, or even difficult to degrade. Therefore, when biodegradable polyester materials exist in water bodies, especially seawater, there is still a risk of potential environmental pollution.

In order to accelerate the degradation rate of biodegradable polyester in water, there is a method of blending starch and biodegradable polyester in the prior art. However, the degradation rate of starch itself in water, especially seawater, is limited, and starch filling is not The mechanical properties of the blend are greatly reduced, so the application of the material is limited. In addition, by blending easily water-soluble polyvinyl alcohol (PVA) with biodegradable polyester, although the overall weight loss of the material is significantly increased, the compatibility of PVA with the resin matrix is poor, and the degradation performance of PVA itself and the degradation of the final product biological Safety is questioned; the existing technology also includes the easy hydrolysis of polyglycolic acid (or polyglycolide, PGA), polylactic acid-glycolic acid copolyester (PLGA), polyethylene glycol oxalate and other water bodies can quickly The hydrolyzed polyester is blended with the biodegradable resin matrix PLA. On the one hand, the easily hydrolyzed part can be quickly degraded in water, and the overall weight loss is obvious. On the other hand, the intermediate product with carboxyl group formed by degradation can further catalyze the biological process of the hardly hydrolyzed PLA. Degradation process.

However, most of the existing technologies use blending, the system is complicated, and the compatibility causes the mechanical properties to be limited, and corresponding additives need to be added, which affects the biological safety. At present, there are many studies on PLA systems, and the mechanical strength of the blends is good but the toughness is insufficient, especially when used in film products, the application is limited.

The prior art introduced the copolymerization of TMC and 1,3 propylene glycol to form a polyester diol, and then the ring-opening polymerization of glycolide and lactide to form a block copolymer containing PGA segments. Involving the synthesis process of PGA and PLGA, most of them are obtained by ring-opening polymerization using expensive lactide and glycolide as raw materials, making the material difficult to implement in specific application processes due to the high cost of raw materials; the prior art also introduces the first synthesis of PBA , PLGA low-molecular-weight polyester diol, and then introduce a chain extender, extend the chain in DMF solution to obtain easily hydrolyzed block copolymer elastomer. The preparation process is complicated, contains non-environmentally friendly chain extenders, the high boiling point DMF solvent is not easy to remove, and the product molecular weight is not high (less than 20,000).

Therefore, it is necessary to provide a new water-degradable copolymer and a preparation method thereof to solve the above-mentioned technical problems.

Summary of the invention

An object of the present invention is to provide a hydrolyzable copolyester, which is biodegradable, has good strength and toughness, can be used to prepare water-degradable products, and can be placed in a natural water environment. Faster degradation.

The second object of the present invention is to provide a method for preparing a hydrolyzable copolyester.

The third object of the present invention is to provide an application of a hydrolyzable copolyester.

To achieve the above-mentioned first objective, the present invention adopts the following technical solutions:

A hydrolyzable copolyester, the molecular chain segment of the copolyester includes a chain segment of a hardly hydrolyzable polyester and a chain segment of an easily hydrolyzable polyester, and the copolyester is a hardly hydrolyzable polyester. Random copolymers or block copolymers composed of ester segments and easily hydrolyzable polyester segments.

Preferably, the hardly hydrolyzable polyester has a TOC (total organic carbon content) measured by a prescribed method of 5 ppm or less, and does not contain water-soluble polyester. Selected from aliphatic polyesters and/or aliphatic-aromatic polyesters and/or aliphatic-aromatic copolyesters obtained by polycondensation reaction, excluding polylactic acid (PLA) and polycaprolactone produced by ring-opening polymerization (PCL) Aliphatic polyester.

Preferably, the aliphatic polyester is selected from one or two of polybutylene succinate (PBS) and polybutylene adipate (PBA).

Preferably, the aliphatic-aromatic polyester is selected from one or two of polybutylene terephthalate (PBT) and polyethylene terephthalate (PET).

Preferably, the aliphatic-aromatic copolyester is selected from polyterephthalate & adipic acid-butanediol ester (PBAT), polysuccinic acid & adipic acid-butanediol ester (PBSA) One or two of them.

Preferably, the easily hydrolyzable polyester has a TOC value higher than 5 ppm, preferably 10 ppm or higher. In addition, it is particularly suitable for a polyester that easily releases acid in water. It is selected from polyglycolic acid (PGA), polyoxalate, polylactic acid-glycolic acid copolyester (PLGA), polyethylene succinate (PES), polyethylene adipate (PEA).

Preferably, the number average molecular weight of the copolyester is 1,000 to 100,000, preferably more than 30,000; preferably 30,000 to 70,000, more preferably 50,000 to 70,000.

Preferably, the molar ratio of the segments of the hardly hydrolyzable polyester to the segments of the easily hydrolyzable polyester is 1:99-99:1.

In order to achieve the above-mentioned second object, the present invention provides a method for preparing the above-mentioned hydrolyzable copolyester. The method includes the following steps:

The dibasic acid and glycol used to form the segment of the hardly hydrolyzable polyester are mixed with the monomer of the easily hydrolyzable polyester, and the copolymer is obtained by esterification and polycondensation in the presence of a catalyst. ester;

or

The dibasic acid, glycol or monomer of the easily hydrolyzable polyester used to form the segment of the hardly hydrolyzable polyester is first esterified and polycondensed in the presence of a catalyst to obtain low molecular weight fragments Hardly hydrolyzable polyester or easily hydrolyzable polyester with low molecular weight fragments;

In the process of esterification and polycondensation of the easily hydrolyzable polyester or the hardly hydrolyzable polyester, the low-molecular-weight fragment of the hardly hydrolyzable polyester or the low-molecular-weight fragment of the easily hydrolyzable polyester is added for copolymerization to form the copolyester;

or

Separately form the segment of the hardly hydrolyzable polyester and the segment of the easily hydrolyzable polyester;

The chain segments of the hardly hydrolyzable polyester and the easily hydrolyzable polyester are mixed and melted to extend the chain to obtain the copolyester.

Preferably, the catalyst is selected from one or a mixture of a titanium-containing catalyst, a tin-containing catalyst or a zinc-containing catalyst.

More preferably, the titanium-containing catalyst is selected from tetra-n-propyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, tetra-tert-butyl titanate, acetyl triisopropyl titanate, One or more of titanium acetate, titanium oxalate, titanium tetrachloride, tetramethyl titanate, tetraethyl titanate, and tetraisopropyl titanate.

More preferably, the tin-containing catalyst is selected from one or more of stannous chloride, stannous oxide, and stannous 2-ethylhexanoate.

More preferably, the zinc-containing catalyst is selected from zinc acetate.

In order to achieve the above-mentioned third object, the present invention provides the application of the above-mentioned hydrolyzable copolyester in the preparation of water-degradable products. The copolyester is processed by suction molding, injection molding, blow molding, film blowing, extrusion, casting, spinning, etc. to form various products. The shapes of the products include sheets, film materials, pipes, etc. It specifically includes disposable dishes, straws, cups, knives, forks, spoons, packaging bags, packaging barrels, bottles, garbage bags, express bags, etc.

The above-mentioned applications also include filling the copolyester before using it to reduce costs or improve heat resistance or mechanical properties.

The above application also includes blending the copolyester as a degradation accelerator in water with other polymer materials to improve the overall degradation rate in water.

Preferably, the water body in which the water-degradable material undergoes water degradation is a natural water environment, and the natural water environment is preferably a natural river, river, lake, sea, and experimental water body or sewage.

The beneficial effects of the present invention are as follows:

In the hydrolyzable copolyester provided by the present invention, the chain segment of the easily hydrolyzable polyester is introduced into the structure, so that the copolyester has better water degradation performance. Further by limiting the molecular weight of the copolyester and the composition and ratio of the segments of the hardly hydrolyzable polyester and the easily hydrolyzable polyester in its molecular structure, no additional additives are required, and the pure resin has both Good water degradation performance and excellent processing performance, heat resistance and mechanical properties. The hydrolyzable copolyester provided by the present invention can be used to prepare various sheets, film materials, pipes, etc., for preparing water-degradable polymer material products.

Description of the drawings

The specific embodiments of the present invention will be described in further detail below in conjunction with the accompanying drawings.

Figure 1 shows the nuclear magnetic spectrum of the copolyester prepared in Example 1.

Figure 2 shows the nuclear magnetic spectrum of the copolyester prepared in Comparative Example 1.

3 shows the nuclear magnetic spectrum of the copolyester prepared in Example 2.

FIG. 4 shows the nuclear magnetic spectrum of the copolyester prepared in Example 3.

5 shows the nuclear magnetic spectrum of the copolyester prepared in Example 4.

6 shows the nuclear magnetic spectrum of the copolyester prepared in Example 5.

detailed description

In order to explain the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments and drawings. Similar components in the drawings are denoted by the same reference numerals. Those skilled in the art should understand that the content described below is illustrative rather than restrictive, and should not limit the protection scope of the present invention.

An embodiment of the present invention provides a hydrolyzable copolyester, the molecular segment of the copolyester includes a segment of a hardly hydrolyzable polyester and a segment of an easily hydrolyzable polyester, and the copolymerization Ester is a random copolymer or block copolymer composed of segments of hardly hydrolyzable polyester and segments of easily hydrolyzable polyester.

In the prior art, the problem of poor hydrolysis of biodegradable polyesters is mainly solved by blending. However, this method has a complicated system and its compatibility leads to limited mechanical properties. Corresponding additives need to be added, which affects biological safety. . Based on this, in this embodiment, this shortcoming is avoided by adopting copolymerization to form a random copolymer or a block copolymer.

It should be noted that, in the present invention, the hardly hydrolyzable polyester means that for the sample polyester, an aqueous dispersion with a concentration of 100 mg/10 ml is prepared, and the aqueous dispersion is hydrolyzed at 45°C and 100 rpm for 7 days, and then The water dispersion was diluted 10 times and the TOC (total organic carbon content) measured was less than 5 ppm. In addition, water-soluble polyester is not included.

Easily hydrolyzable means that TOC measured in the same manner as above is greater than 5 ppm.

There are many types of biodegradable polyesters and easily hydrolyzed polyesters, with different synthesis methods. If you want to select a suitable biodegradable polyester and an easily hydrolyzable polyester and copolymerize the two to obtain a copolymer that is cheap and easy to obtain, high molecular weight, high mechanical properties, and can be hydrolyzed in compost and natural water, then copolymerization At the same time, the key factors such as the selection of biopolyester matrix and easily hydrolyzable matrix and their synthetic raw materials, copolymerization method, raw material ratio of the copolymerization process, temperature, vacuum, reaction time, catalyst selection and dosage, etc. require a lot of experimental verification. In addition, from the perspective of practical applications, raw materials and preparation costs are also important considerations for materials.

The hardly hydrolyzable polyester is a polyester whose TOC (total organic carbon content) measured by a prescribed method is 5 ppm or less and does not contain a water-soluble polyester. In a preferred example, in the copolyester, the segment of the hardly hydrolyzable polyester is a hardly hydrolyzable biodegradable polyester, and specifically may be an aliphatic polyester and/or aliphatic-aromatic obtained by a polycondensation reaction. Polyester and/or aliphatic-aromatic copolyester. Wherein, the aliphatic polyester includes, but is not limited to, obtained by esterification-condensation.

Exemplary aliphatic polyesters obtained by polycondensation reaction may be one or two of polybutylene succinate (PBS) and polybutylene adipate (PBA). For example, when the hardly hydrolyzable polyester is polybutylene succinate, the segment of the hardly hydrolyzable polyester may be

Where x is any natural number from 1-1000. It can be understood that the aliphatic polyester obtained by the polycondensation reaction does not include PLA or polycaprolactone (PCL) aliphatic polyester produced by ring-opening polymerization.

The exemplary aliphatic-aromatic polyester may be one or both of polybutylene terephthalate (PBT) and polyethylene terephthalate (PET).

Exemplary aliphatic-aromatic copolyesters can be polyterephthalate & adipic acid-butylene glycol ester (PBAT), polysuccinic acid & adipic acid-butylene glycol ester (PBSA), etc. One or a mixture of several. For example, when the aliphatic-aromatic copolyester is PBAT, the segment of the hardly hydrolyzable polyester can be

Where m and y are any natural numbers from 1-1000.

In the aliphatic-aromatic copolyester, the ratio of the two dibasic acids is added so as not to impair the overall thermodynamic properties and degradation performance of the copolyester. More preferably, the aliphatic-aromatic copolymer In the ester, the molar ratio of the two dibasic acids is 1:9-9:1.

In addition, as long as the overall thermodynamic properties and degradation properties of the copolyester are not impaired, the above-mentioned hardly hydrolyzable polyesters also include other polyesters obtained from dibasic acids and dihydric alcohols, as well as various aliphatic polyols and fats. Copolyester obtained by copolymerization of polybasic acids, hydroxycarboxylic acids, lactones, etc.

Examples of such diols include ethylene glycol, propylene glycol, butylene glycol, octanediol, dodecanediol, neopentyl glycol, glycerin, pentaerythritol, sorbitol, polyethylene glycol, and the like.

Examples of dibasic acids include oxalic acid, succinic acid, adipic acid, sebacic acid, glutaric acid, decane dicarboxylic acid, cyclohexane dicarboxylic acid, terephthalic acid, and phthalic acid.

Examples of hydroxycarboxylic acids include glycolic acid, hydroxypropionic acid, hydroxyvaleric acid, hydroxycaproic acid, and mandelic acid.

Examples of lactones include caprolactone, butyrolactone, valerolactone, undecanolide, glycolide, mandelic acid lactone, and the like.

Among the segments of the easily hydrolyzable polyester, the easily hydrolyzable polyester is more hydrolyzable than the biodegradable resin. The presence of the easily hydrolyzable polyester segments endows the copolyester with good degradability in natural water environments. The easily hydrolyzable polyester preferably has a TOC value higher than 5 ppm, preferably 10 ppm or higher, and is particularly suitable for a polyester that easily releases acid in water. In a preferred example, the easily hydrolyzable polyester is selected from polyglycolic acid (PGA), polyoxalate, polylactic acid-glycolic acid copolyester (PLGA), polyethylene succinate (PES) , One or more of polyethylene adipate (PEA).

Among them, the above-mentioned polyoxalate is a polyester or copolyester prepared using oxalic acid as a dibasic acid.

In addition, when polylactic acid-glycolic acid copolyester (PLGA) is used as an easily hydrolyzed segment, the copolyester can be a random copolyester or a block copolyester. The molar ratio of LA and GA can be 0.1:99.9 -99.9:0.1. When the ratio of LA to GA is 1:1, the polyester has the fastest hydrolysis rate. The improvement of the hydrolysis performance of the copolyester is more obvious. As the ratio of LA or GA increases, the hydrolyzability decreases, approaching PLA and PGA respectively. The improvement of copolyester hydrolysis is closer to PLA and PGA. It can be seen that the ratio of LA should not be too large, and the molar ratio of LA to GA is preferably 0.1:99.9-95:5, and more preferably 0.1:99.9-90:1.

The water body mentioned in this embodiment includes natural water environment, which can be natural rivers, rivers, lakes, seas, experimental water bodies or various sewage. Among them, there are differences in the types and quantities of microorganisms, water temperature, and pH values in different water environments. The hydrolyzable copolyester in this embodiment can be degraded in the aforementioned water bodies, and the degradation rate is higher than that of the existing commercial biodegradable polyester in natural water environment. That is, the copolyester in this example and the corresponding commercial biodegradable polyester with the same or similar molecular weight, in the same water environment, the copolyester exhibits faster mechanical properties than the commercial biodegradable polyester , Decrease of molecular weight and weight loss. Or in the same water environment, the time taken for the copolyester in this application to drop to 50% of its original mechanical properties or its weight loss to 50%, or its molecular weight to drop to 20% is shorter than that of commercial biodegradable polyester .

Preferably, the number average molecular weight of the copolyester is 1,000 to 100,000. From the viewpoints of formability and usability, the copolyester preferably has a molecular weight of 30,000 or more, for example, 30,000 to 70,000, more preferably 50,000 to 50,000. 70000.

The copolyester in the water body, on the one hand, because the easily hydrolyzable polyester segments are easily hydrolyzed and broken, so that the molecular weight of the copolyester decreases rapidly, on the other hand, the fragments of the easily hydrolyzable polyester segments are broken to produce degradation containing terminal carboxyl groups. The intermediate product can further promote the hydrolysis reaction of the resin body. Therefore, the copolyester has a faster rate of hydrolysis than the biodegradable polyester that does not contain segments of easily hydrolyzable polyester. Especially when the hardly degradable segment of the copolyester is PET, which is neither biodegradable nor hydrolyzable, and the easily hydrolyzed segment is rapidly hydrolyzed PLGA, the rapid hydrolysis of the PLGA segment and acid hydrolyzate can make the copolymerization Esters have good degradation properties in water.

Under normal circumstances, when the proportion of easily hydrolyzable polyester chains is smaller, the overall performance of the copolyester is close to that of the hardly hydrolyzable polyester, especially its hydrolysis performance decreases. When the proportion of non-hydrolyzable polyester segments is larger, the overall hydrolysis performance of the copolyester increases. However, for the combination of different hardly hydrolyzable polyester segments and easily hydrolyzable polyester segments, the hydrolysis performance, thermal, mechanical properties, and processing performance influencing factors and results are not the same. That is, the increase in hydrolysis performance does not mean the increase or decrease in thermal, mechanical properties and/or processing performance. In a preferred example, the molar ratio of the segments of the hardly hydrolyzable polyester to the segments of the easily hydrolyzable polyester is preferably 1:99-99:1, more preferably 70:30-30:70. At this time, the copolyester has both better hydrolyzability and good strength and toughness, and can be formed into various types including one-time processing by suction molding, injection molding, blow molding, blown film, extrusion, casting, spinning, etc. Sexual dishes, straws, cups, knives, forks, spoons, packaging bags, packaging barrels, bottles, garbage bags, express bags and other products.

Another embodiment of the present invention provides a preparation method of the above-mentioned hydrolyzable copolyester. In one embodiment, the preparation method includes the following steps:

The dibasic acid and glycol used to form the segment of the hardly hydrolyzable polyester are mixed with the monomer of the easily hydrolyzable polyester, and the copolymer is obtained by esterification and polycondensation in the presence of a catalyst. Ester, the copolymer at this time is a random copolymer.

It can be understood that the above-mentioned dibasic acid and diol forming the segment of the hardly hydrolyzable polyester can be exemplified. When the hardly hydrolyzable polyester is PBS, the dibasic acid forming PBS is 1,4- Succinic acid, the diol is 1,4-butanediol, and the content of 1,4-butanediol is 1-2 times the molar content of 1,4-butanedioic acid. At this time, the monomer of easily hydrolyzable polyester The molar ratio of body to 1,4-succinic acid is 1:99-99:1. The dibasic acids and glycols used as raw materials can be petroleum-based or can be obtained by biological fermentation.

In this preparation method, the monomer of the easily hydrolyzable polyester may be exemplified by the fact that when the easily hydrolyzable polyester is polyglycolic acid, the monomer is glycolic acid or glycolide, preferably cheap glycolic acid. By adjusting the introduction amount of the monomer of the easily hydrolyzable polyester, the size and content of the difficult-to-hydrolyze and easily hydrolyzable segments in the copolyester are adjusted, and the degradation rate of the copolyester in the water body is adjusted. Generally, the amount of monomers of the easily hydrolyzable polyester is directly proportional to the content of the easily hydrolyzable polyester segments in the copolyester.

In a preferred example, the catalyst used in the preparation method may be one of a titanium-containing catalyst, a tin-containing catalyst, or a zinc-containing catalyst. The catalyst can be added during the esterification reaction, or during the polycondensation reaction, or added stepwise. Preferably, according to the catalyst activity, it is added during the polycondensation. In the preparation method, only one catalyst is needed to obtain the copolyester in one step when esterification and polycondensation reactions occur. Compared with the existing preparation methods, the method is simpler and easier to obtain.

More preferably, the zinc-containing catalyst is selected from zinc acetate.

In the preparation method, the preparation process can also be carried out by adding a compound phosphate, pyrophosphate, phosphonate, phosphinate, phosphite or a salt of phosphate or phosphonate, or a phosphorus derivative of a hydroxy acid. It is preferably at least one of trimethyl phosphate, triethyl phosphate, tripropyl phosphate, triethylpropyl phosphate, tributyl phosphate, triphenyl phosphate, triethyl phosphite, and trimethyl phosphite as Stabilizer to improve the color value of the copolyester and increase the molecular weight.

In the preparation method, a fourth monomer such as glycerin, pentaerythritol and other polyhydric alcohols and polybasic acids can be added to further increase the molecular weight and mechanical strength.

In the preparation method, organic or inorganic nucleating agents (inorganic nanoparticles, fibers, etc.) can also be added in the preparation process to improve the crystallization, heat resistance and mechanical properties of the copolyester.

or

In another aspect, the preparation method includes the following steps:

In the process of esterification and polycondensation of the easily hydrolyzable polyester or the hardly hydrolyzable polyester, the hardly hydrolyzable polyester of the low molecular weight fragment or the easyly hydrolyzable polyester of the low molecular weight fragment is added for copolymerization to form the copolyester. The copolymer at this time is a block copolymer.

or

In another aspect, the preparation method includes the following steps:

The chain segments of the hardly hydrolyzable polyester and the easily hydrolyzable polyester are mixed and melted to obtain the copolyester. The copolymer at this time is a block copolymer.

In this preparation method, the chain segment of the hardly hydrolyzable polyester can be obtained by polycondensation of the dibasic acid and glycol used to form the chain segment of the hardly hydrolyzable polyester. Among them, the selection of dibasic acid and glycol can be as described above.

In the preparation method, exemplary chain extenders can be isocyanate chain extenders such as TDI and HDI, or one or more of various epoxy chain extenders. It is preferably an environmentally friendly epoxy chain extender. Through the method of melting chain extension, no solvent is required, easy to process, and wider application range.

Another embodiment of the present invention provides the application of the hydrolyzable copolyester in the preparation of water-degradable products.

Preferably, the copolyester is processed to form various water-degradable products by means of suction molding, injection molding, blow molding, blown film, extrusion, casting, spinning, etc. The shape of the product includes sheet and film materials. , Pipes, etc. These include but are not limited to disposable dishes, straws, cups, knives, forks, spoons, packaging bags, packaging barrels, bottles, garbage bags, express bags, etc.

The above-mentioned application also includes blending the copolyester with other polymer materials before processing and forming.

Hereinafter, it will be described in conjunction with some specific embodiments:

Example 1

A method for preparing a hydrolyzable copolyester includes the following steps:

1,4-butanedioic acid 10mol, 1,4-butanediol (excess) 15mol, glycolic acid 1mol, 160-180℃ after esterification for 2h, add 6.5g catalyst tetrabutyl titanate, 200-230℃ high vacuum The random copolyester PGBS1 is obtained by polycondensation for 4h, and its structural formula is shown in the following formula:

It was determined that the random copolyester of M _n = 49600, a tensile strength of 35MPa, the elongation at break of 120%, a melting point of 105 deg.] C, NMR spectrum as shown in FIG. It takes 4 months for its molecular weight to drop to 1/10 in distilled water at 40°C. 70% weight loss a year in natural seawater. The copolyester can be processed into disposable tableware such as cutlery or spoon by injection molding or suction molding.

Comparative example 1

The preparation method of PBS includes the following steps:

1,4-butanedioic acid 10mol, 1,4-butanediol (excess) 15mol, 160-180℃ after esterification for 2h, adding 7.0g catalyst tetrabutyl titanate, 200-230℃ polycondensation for 4h to obtain PBS. Mn=51600, tensile strength 38MPa, elongation at break 220%, melting point 113°C. The NMR spectrum is shown in Figure 2 and it takes 15 months for the molecular weight to drop to 1/10 in distilled water at 40°C. Weight loss in natural seawater is 4% a year.

Example 2

A method for preparing a hydrolyzable copolyester includes the following steps:

1,4-butanedioic acid 10mol, 1,4-butanediol (excess) 15mol, glycolide 1mol, 160-180℃ after esterification for 2h, add 5.5g catalyst tetraisopropyl titanate, stannous chloride 0.3g, 200-230℃ high-vacuum polycondensation for 4.5h to obtain random copolyester PGBS2, its structural formula is as follows:

It was determined that the random copolyester of M _n = 50200, a tensile strength of 34MPa, elongation at break of 130%, m.p. 105 ℃. The NMR spectrum is shown in Figure 3, and it takes 4 months for its molecular weight to drop to 1/10 in distilled water at 40°C. 70% weight loss a year in natural seawater. The copolyester can be processed into various pipes through twin screw extrusion.

Example 3

A method for preparing a hydrolyzable copolyester includes the following steps:

1,4-butanedioic acid 10mol, 1,4-butanediol (excess) 15mol, 160-180℃ after esterification for 2h, add 7.0g catalyst tetrabutyl titanate, 200-230℃ high vacuum polycondensation for 1h to obtain PBS Oligomer. Glycolic acid 2mol, stannous chloride 0.3g, 160℃ esterified for 1h, 170-180℃ high vacuum polycondensation for 0.5h to obtain PGA oligomer. After mixing the above PBS oligomer and PGA oligomer, HDI chain extender is added, and the chain is extended at 120-180°C in the upper screw extruder to obtain PGBS3 block copolyester. Its structure is shown in the following formula:

It was determined that its M _n =39600, the tensile strength was 30MPa, the elongation at break was 80%, and the melting point was 102°C. The NMR spectrum is shown in Figure 4. It takes 3 months for its molecular weight to drop to 1/10 in distilled water at 40°C. 90% weight loss a year in natural seawater. The copolyester can be processed into drinking water cups by injection molding.

Example 4

A method for preparing a hydrolyzable copolyester includes the following steps:

Glycolic acid 3mol, stannous chloride 0.3g, 160°C esterification for 1h, 170-180°C polycondensation for 0.5h to obtain PGA oligomer; 1,4-butanedioic acid 10mol, 1,4-butanediol (excess) 15mol Mix and esterify at 160-180℃ for 2h, add 7.0g of catalyst tetrabutyl titanate and the above-mentioned PGA oligomer, 200-230℃ high-vacuum polycondensation for 4h to obtain PGBS4 copolyester, its structure is shown in the following formula:

After measurement, its M _n =48900, tensile strength 31MPa, elongation at break 180%, and melting point 99°C. The NMR spectrum is shown in Figure 5, and the time required for its molecular weight to drop to 1/10 in distilled water at 40°C is 2 months. 100% weight loss a year in natural seawater. The copolyester can be used as a hydrolysis accelerator to blend with PBS to promote the degradation performance of PBS in water.

Example 5

A method for preparing a hydrolyzable copolyester includes the following steps:

1,4-butanedioic acid 10mol, 1,4-butanediol (excess) 15mol mixed, 160-180℃ after esterification for 2h, add 7.0g catalyst tetrabutyl titanate, 200-230℃ high vacuum polycondensation after 1h PGBS5 is obtained by adding 5 mol of glycolic acid, reacting in low vacuum at 190°C for 1 hour, and polycondensing in high vacuum at 200-230°C for 4 hours. The structural formula is similar to that in Example 1 above. Its M _n =49200, tensile strength 37MPa, breaking elongation 280%, melting point 93°C. The NMR spectrum is shown in Figure 6, and it takes 1 month for its molecular weight to drop to 1/10 in distilled water at 40°C. 100% weight loss a year in natural seawater. The copolyester can be processed into various sheets by casting.

Example 6

A method for preparing a hydrolyzable copolyester includes the following steps:

1,4-butanedioic acid 10mol, 1,4-butanediol (excess) 15mol, glycolic acid 1mol, L-lactic acid 3mol, 160-180℃ after esterification for 2h, add 5.5g catalyst tetrabutyl titanate, chlorine 0.8g of stannous, high vacuum polycondensation at 200-230℃ for 4 hours to obtain random copolyester PLBBS3, its structure is shown in the following formula:

Its M _n =52600, tensile strength 35MPa, elongation at break 120%, melting point 93°C. It takes 1 month for its molecular weight to drop to 1/10 in distilled water at 40°C. 100% weight loss a year in natural seawater. The copolyester can be used as a hydrolysis accelerator to blend with PLA to promote the degradation performance of PLA in water.

Example 7

A method for preparing a hydrolyzable copolyester includes the following steps:

Adipic acid 5.5 mol, terephthalic acid 4.5 mol, 1,4-butanediol (excess) 15 mol, glycolic acid 3.3 mol, 170-200 ℃ after esterification for 2 hours, add catalyst tetrabutyl titanate 10g, 200- The random copolyester PGBAT1 was obtained by high-vacuum polycondensation at 250°C for 5 hours, the structure of which is as follows:

Its Mn=50600, tensile strength 26MPa, breaking elongation 800%, melting point 93°C. As shown, it takes 2 months for its molecular weight to drop to 1/10 in distilled water at 40°C. 100% weight loss a year in natural seawater. The copolyester can be used to prepare disposable shopping bags by film blowing.

Example 8

A method for preparing a hydrolyzable copolyester includes the following steps:

3mol of glycolic acid, 2mol of L-lactic acid, 5wt% of stannous chloride, water removal at 160°C for 1h, high vacuum at 170-190°C for 0.5h, to obtain PLGA oligomer; 5.5mol of adipic acid, 4.5mol of terephthalic acid, 1,4-butanediol (excess) 15mol, 170-200℃ after esterification for 2h, add catalyst tetrabutyl titanate 10g and the above PLGA oligomer, 200-250℃ high vacuum polycondensation for 5h to obtain random copolyester PGBAT2, its structural formula is as follows:

Its M _n =49600, tensile strength 25MPa, elongation at break 420%, melting point 90°C. As shown, it takes 1 month for its molecular weight to drop to 1/10 in distilled water at 40°C. 100% weight loss a year in natural seawater. The copolyester can be blown film to prepare disposable packaging bags or garbage bags.

Example 9

Terephthalic acid 10mol, ethylene glycol (excess) 15mol, glycolic acid 3mol, L-lactic acid 2mol, 170-200℃ after esterification for 2h, add catalyst tetrabutyl titanate 10g, 280-290℃ high vacuum polycondensation for 4h The structure of random copolyester PLGET is as follows:

Its Mn=51800, tensile strength 45MPa, elongation at break 270%, melting point 250°C. It takes 4 months for its molecular weight to drop to 1/10 in distilled water at 40°C. 100% weight loss a year in natural seawater. The copolyester can be directly spun from the melt to prepare polyester fiber.

Example 10

Terephthalic acid 10mol, butanediol (excess) 15mol, glycolic acid 2mol, L-lactic acid 3mol, 170-200℃ after esterification for 2h, add catalyst tetrabutyl titanate 10g, 280-290℃, high vacuum polycondensation 4h The random copolyester PLBBT has Mn=56800, tensile strength 40MPa, elongation at break 170%, and melting point 224°C. It takes 4 months for its molecular weight to drop to 1/10 in distilled water at 40°C. 100% weight loss a year in natural seawater. The copolyester can be used to prepare polyester film and polyester bottle through film blowing and blow molding.

Obviously, the above-mentioned embodiments of the present invention are merely examples to clearly illustrate the present invention, and are not intended to limit the implementation of the present invention. For those of ordinary skill in the art, they can also do on the basis of the above description. In addition to other different forms of changes or changes, it is not possible to list all the implementations here. Any obvious changes or changes derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

A hydrolyzable copolyester, characterized in that the molecular chain segment of the copolyester includes a chain segment of a hardly hydrolyzable polyester and a chain segment of an easily hydrolyzable polyester, and the copolyester is Random copolymer or block copolymer composed of segments of hardly hydrolyzable polyester and segments of easily hydrolyzable polyester.
The copolyester according to claim 1, wherein the hardly hydrolyzable polyester is selected from aliphatic polyesters and/or aliphatic-aromatic polyesters and/or aliphatic-aromatics obtained by polycondensation reaction. Group copolyester.
The copolyester according to claim 2, wherein the aliphatic polyester is selected from one or two of polybutylene succinate and polybutylene adipate; preferably , The aliphatic-aromatic copolyester is selected from one or two of polyterephthalate & adipate-butylene glycol ester, polysuccinic acid & adipate-butylene glycol ester; preferably Preferably, the aliphatic-aromatic polyester is selected from one or two of polybutylene terephthalate and polyethylene terephthalate.
The copolyester according to claim 1, wherein the easily hydrolyzable polyester is selected from the group consisting of polyglycolic acid, polyoxalate, polylactic acid-glycolic acid copolyester, and polyethylene succinate , One or more of polyethylene adipate.
The copolyester according to claim 1, wherein the number average molecular weight of the copolyester is 1,000 to 100,000, more preferably 30,000 to 70,000.
The copolyester according to claim 1, wherein the molar ratio of the segments of the hardly hydrolyzable polyester to the segments of the easily hydrolyzable polyester is 1:99-99:1.
The preparation method of copolyester according to any one of claims 1 to 6, characterized in that it comprises the following steps:

The dibasic acid and glycol used to form the segment of the hardly hydrolyzable polyester are mixed with the monomer of the easily hydrolyzable polyester, and the copolymer is obtained by esterification and polycondensation in the presence of a catalyst. ester;

or

The dibasic acid, glycol or monomer of the easily hydrolyzable polyester used to form the segment of the hardly hydrolyzable polyester is first esterified and polycondensed in the presence of a catalyst to obtain low molecular weight fragments Hardly hydrolyzable polyester or easily hydrolyzable polyester with low molecular weight fragments;

In the process of esterification and polycondensation of the easily hydrolyzable polyester or the hardly hydrolyzable polyester, the low-molecular-weight fragment of the hardly hydrolyzable polyester or the low-molecular-weight fragment of the easily hydrolyzable polyester is added for copolymerization to form the copolyester;

or

Separately form the segment of the hardly hydrolyzable polyester and the segment of the easily hydrolyzable polyester;

The chain segments of the hardly hydrolyzable polyester and the easily hydrolyzable polyester are mixed, and the chain is extended by melting to obtain the copolyester.
The preparation method according to claim 7, wherein the catalyst is selected from one or a mixture of a titanium-containing catalyst, a tin-containing catalyst or a zinc-containing catalyst; preferably, the titanium-containing catalyst is selected from Tetra-n-propyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, tetra-tert-butyl titanate, acetyl triisopropyl titanate, titanium acetate, titanium oxalate, titanium tetrachloride, One or more of tetramethyl titanate, tetraethyl titanate, and tetraisopropyl titanate; preferably, the tin-containing catalyst is selected from stannous chloride, stannous oxide, and 2-ethylhexyl One or more of stannous acid; preferably, the zinc-containing catalyst is selected from zinc acetate.
The use of the hydrolyzable copolyester according to any one of claims 1 to 6 in the preparation of water-degradable products.