Modified chain extender and preparation method and application thereof
阅读说明：本技术 一种改性扩链剂及其制备方法和应用 (Modified chain extender and preparation method and application thereof ) 是由 金杰 张元华 陈焕辉 黄志洪 王晋园 项超力 崔燕军 唐劲松 于 2021-01-15 设计创作，主要内容包括：本发明涉及一种改性扩链剂及其制备方法和应用,所述改性扩链剂的制备原料按照质量百分比包括如下组分：多元醇60～95wt％,异氰酸酯5～40wt％,第一催化剂0.001～1wt％,所述异氰酸酯与多元醇的摩尔比例为(1.5～5):1。本发明提供的多元醇改性的异氰酸酯扩链剂能够在生物可降解聚酯中良好的分散,避免了异氰酸酯的局部过量,解决膜制品形成凝胶或晶点的问题,同时,改性后的扩链剂不易挥发、且更容易控制异氰酸酯扩链剂与生物可降解聚酯中羟基的反应活性,生产过程更加稳定易控。(The invention relates to a modified chain extender and a preparation method and application thereof, wherein the modified chain extender comprises the following raw materials in percentage by mass: 60-95 wt% of polyol, 5-40 wt% of isocyanate and 0.001-1 wt% of first catalyst, wherein the molar ratio of the isocyanate to the polyol is (1.5-5): 1. The polyol modified isocyanate chain extender provided by the invention can be well dispersed in biodegradable polyester, so that the local excess of isocyanate is avoided, the problem that a membrane product forms gel or crystal points is solved, meanwhile, the modified chain extender is not easy to volatilize, the reactivity of the isocyanate chain extender and hydroxyl in the biodegradable polyester is more easily controlled, and the production process is more stable and easy to control.)
1. The modified chain extender is characterized by comprising the following raw materials in percentage by mass:
60-95 wt% of polyhydric alcohol
5-40 wt% of isocyanate
0.001 to 1 wt% of a first catalyst
The molar ratio of the isocyanate to the polyol is (1.5-5): 1.
2. The modified chain extender of claim 1, wherein the polyol comprises any one or a combination of at least two of polyester polyol, polyether polyol, polycarbonate polyol, or polyether modified siloxane;
preferably, the number average molecular weight of the polyol is 400-8000 Dalton, preferably 500-3000 Dalton, and further preferably 600-2000 Dalton;
preferably, the isocyanate includes any one or a combination of at least two of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1, 4-cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, methylcyclohexyl diisocyanate, cyclohexane dimethyldiisocyanate, or trimethyl-1, 6-hexamethylene diisocyanate.
3. The modified chain extender of claim 1 or 2 wherein the first catalyst comprises an amine catalyst and/or an organometallic catalyst;
preferably, the amine catalyst comprises any one or a combination of at least two of triethylamine, tributylamine, triethylenediamine, N-ethylmorpholine, N' -tetramethyl-ethylenediamine, pentamethyldiethylenetriamine, N-methylaniline, N-dimethylaniline, or 1, 8-diazabicycloundec-7-ene;
preferably, the organometallic catalyst comprises any one or a combination of at least two of stannous acetate, stannous octoate, ethylhexyltin, dibutyltin dilaurate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin maleate, dioctyltin diacetate, bismuth isooctanoate, bismuth neodecanoate, zinc isooctanoate, or zirconium isooctanoate.
4. The modified chain extender of any one of claims 1 to 3, wherein the modified chain extender has a mass content of isocyanate groups of 1 to 25 wt.%, preferably 1.5 to 15 wt.%.
5. A method for preparing the modified chain extender of any one of claims 1 to 4, wherein the method comprises the following steps: and mixing the polyol, the isocyanate and the first catalyst according to the formula ratio, and carrying out polycondensation reaction to obtain the modified chain extender.
6. The preparation method according to claim 5, wherein the polycondensation reaction is carried out until the mass content of isocyanate groups in the modified chain extender is 1 to 25 wt%, preferably 1.5 to 15 wt%;
preferably, the temperature of the polycondensation reaction is 50-200 ℃, preferably 60-150 ℃, and further preferably 60-120 ℃.
7. Use of a modified chain extender as claimed in any one of claims 1 to 4 in the chain extension of biodegradable polyesters.
8. A biodegradable polyester, characterized in that the biodegradable polyester is prepared by reacting a polyester raw material with the modified chain extender of any one of claims 1 to 4.
9. The biodegradable polyester according to claim 8, wherein said polyester raw material comprises any one or combination of at least two of polybutylene terephthalate-adipate, polybutylene succinate-adipate, polylactic acid, polycaprolactone or polymethyl ethylene carbonate, preferably polybutylene terephthalate-adipate.
10. A film product comprising the biodegradable polyester according to claim 8 or 9.
Technical Field
The invention belongs to the technical field of polyester, and particularly relates to a modified chain extender, and a preparation method and application thereof.
Background
The traditional plastic material is not degradable, brings huge and irreversible damage to the environment, and along with the improvement of the understanding of environmental protection, people are more and more urgent to find biodegradable plastic to replace the traditional material, and the biodegradable material is one of the most effective ways for solving the white pollution at present.
The biodegradable high molecular material can be decomposed by bacteria, fungi, yeasts, algae and other microorganisms under the composting condition and converted into carbon dioxide and water. The biodegradable polyester is a main type in biodegradable materials, and comprises polybutylene terephthalate-adipate (PBAT), polybutylene succinate (PBS), polybutylene succinate-adipate (PBSA), polylactic acid (PLA), Polycaprolactone (PCL), polymethyl ethylene carbonate (PPC) and the like. There is a trend in the packaging field to gradually replace traditional plastics, particularly for disposable packaging applications. Among them, PBAT, PBS and PBSA are particularly suitable for the application of packaging films due to their excellent mechanical properties. Such applications typically employ blow molding, casting or extrusion processes, usually employing low melt index materials in order to ensure melt stability and good mechanical strength during processing.
Since the biodegradable polyester stays in the polycondensation reactor for a long time during polycondensation, a thermal degradation reaction is likely to occur, and it is difficult to obtain a high molecular weight polyester product. Meanwhile, the content of terminal carboxyl groups of the product is increased due to the degradation reaction, so that the hydrolytic stability and the thermal stability of the biodegradable polyester product are deteriorated, and the problems of hydrolysis or thermal degradation and the like easily occur in raw material storage and downstream modification or film blowing processing. The chain extension process can effectively shorten the retention time of the biodegradable polyester in the polycondensation reactor, easily obtain the resin with high molecular weight/low melting index, and has low carboxyl end group content, good hydrolytic stability and thermal stability. The chain extension process is a process for further improving the molecular weight of the biodegradable polyester and reducing the melt index by obtaining the biodegradable polyester with high melt index through condensation polymerization, mixing the biodegradable polyester with a chain extender for reaction and reacting in a molten state or a solution. The chain extender is an important key component in the process of synthesizing the biodegradable high polymer material. Isocyanate is a common chain extender because of its high reactivity, easy chemical reaction with the terminal hydroxyl groups of biodegradable polyester, and moderate cost.
CN102007159A discloses isocyanate or isocyanate polymer as chain extender, which has the disadvantages of large difference in polarity and viscosity between isocyanate and PBAT, easy uneven dispersion of isocyanate in polyester, local excess of isocyanate, self-polymerization, greatly increased allophanate content, formation of cross-linking, and many side reactions. The method is difficult to control, has severe adding mode and reaction condition to isocyanate, is easy to form gel or crystal points, and is difficult to be applied to the fields of films and the like.
CN109312061A discloses a method for chain extension by using epoxy compounds, but the method has the disadvantages of expensive raw materials, low production efficiency, poor mechanical strength of the polyester prepared after chain extension, and difficult industrial application.
Therefore, the development of a chain extender which has good dispersibility in polyester, is not easy to form gel or crystal points and has low cost is urgently needed in the field, and the polyester after chain extension has good mechanical properties.
Disclosure of Invention
The invention aims to provide a modified chain extender, in particular to a modified chain extender for biodegradable polyester, which has the advantages of good dispersibility in polyester, difficult gel or crystal point formation and low cost, and the polyester obtained by chain extension has good mechanical properties.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a modified chain extender, which comprises the following raw materials in percentage by mass:
60-95 wt% of polyhydric alcohol
5-40 wt% of isocyanate
0.001 to 1 wt% of a first catalyst
The molar ratio of the isocyanate to the polyol is (1.5-5): 1, for example, 1.6:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 3.9:1, and the like.
In the formula, the mass percent of the polyhydric alcohol is 60-95 wt%, such as 70 wt%, 75 wt%, 76 wt%, 78 wt%, 81 wt%, 86 wt%, 89 wt% and the like; 5 to 40% by mass of isocyanate, for example, 11%, 14%, 19%, 22%, 24%, 25%, 30%, 39% by mass; the first catalyst is contained in an amount of 0.001 to 1 wt%, for example, 0.009 wt%, 0.01 wt%, 0.02 wt%, 0.04 wt%.
The modified chain extender is prepared by carrying out polycondensation reaction on polyol and isocyanate in the raw materials.
Compared with the isocyanate chain extender in the prior art, the modified chain extender for the biodegradable polyester is prepared by modifying isocyanate by adopting polyol, so that on one hand, the compatibility of the isocyanate chain extender and the biodegradable polyester can be improved, the dispersion problem of the isocyanate chain extender in the biodegradable polyester is well solved, the local excess of the isocyanate is avoided, and the problem that a film product forms gel or crystal points is solved; on the other hand, the volatility of the isocyanate can be obviously reduced by modifying the chain extender, and the quality fluctuation caused by the volatilization of the isocyanate can be avoided when the isocyanate reacts with the biodegradable polyester; in addition, the isocyanate chain extender modified by the polyol has relatively high viscosity, and can further improve the dispersibility of the isocyanate chain extender in the biodegradable polyester; in addition, after the polyol modification, the reactivity of the isocyanate chain extender and hydroxyl in the biodegradable polyester can be controlled more easily, and the production process is more stable and controllable.
In addition, the researchers of the invention find that the technical effects can be achieved only if the molar ratio of the-NCO group of the isocyanate to the-OH group of the polyol is within the range of (1.5-5): 1, if the molar ratio of the isocyanate is higher, the effects of improving the dispersibility and reducing the gel content are difficult to obtain, and if the molar ratio of the polyol is higher, the content of the effective functional group of the prepared chain extender is reduced, and the chain extension efficiency is reduced.
Preferably, the polyol comprises any one or a combination of at least two of a polyester polyol, a polyether polyol, a polycarbonate polyol, or a polyether modified siloxane.
Preferably, the polyester polyol includes any one of or a combination of at least two of poly-1, 4-butylene adipate glycol, poly-1, 4-butylene glycol adipate glycol, poly-ethylene glycol adipate glycol, poly-diethylene glycol adipate glycol, poly-neopentyl glycol-1, 4-butylene glycol adipate glycol, poly-ethylene glycol adipate glycol-diethylene glycol diol, or poly-1, 4-butylene glycol adipate glycol-diethylene glycol diol.
Preferably, the polyether polyol is formed by the polyaddition reaction of an initiator and an epoxy compound in the presence of a second catalyst.
Preferably, the initiator is an active hydrogen group-containing compound, preferably any one or a combination of at least two of ethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, diethylene glycol or trimethylolpropane.
Preferably, the epoxy compound comprises any one or a combination of at least two of ethylene oxide, 1, 2-propylene oxide, 1, 2-butylene oxide or 2, 3-butylene oxide.
Preferably, the second catalyst comprises any one or a combination of at least two of an alkali hydroxide, an alkali alkoxide, a double metal complex catalyst (DMC) or a phosphazene-based catalyst.
Preferably, the polyether modified siloxane comprises polyhydroxy silicone oil with number average molecular weight of 400-5000 (such as 1000), and polyhydroxy silicone oil with number average molecular weight of 500-3000 is preferred. "polyhydroxy" means containing at least two hydroxyl groups.
In the present invention, the polycarbonate polyol is a polymer having a repeating carbonate group (-O-COO-) in a molecular main chain and a hydroxyl group (-OH) as a terminal group, and is obtained by reacting one or at least two alkylene oxides with carbon dioxide.
Preferably, the polyol has a number average molecular weight of 400 to 8000Dalton, such as 1000, 2000, etc., preferably 500 to 3000Dalton, and more preferably 600 to 2000 Dalton.
Preferably, the isocyanate includes any one or a combination of at least two of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1, 4-cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, methylcyclohexyl diisocyanate, cyclohexane dimethyldiisocyanate, or trimethyl-1, 6-hexamethylene diisocyanate.
Preferably, the isocyanates further include toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1, 4-cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, methylcyclohexyl diisocyanate, cyclohexanedimethyl diisocyanate or cyclic dimers, trimers, pentamers and higher polymerization degree polyisocyanates of trimethyl-1, 6-hexamethylene diisocyanate.
Preferably, the first catalyst comprises an amine catalyst and/or an organometallic catalyst.
Preferably, the amine catalyst comprises any one or a combination of at least two of triethylamine, tributylamine, triethylenediamine, N-ethylmorpholine, N' -tetramethyl-ethylenediamine, pentamethyldiethylenetriamine, N-methylaniline, N-dimethylaniline or 1, 8-diazabicycloundec-7-ene.
Preferably, the organometallic catalyst comprises any one or a combination of at least two of stannous acetate, stannous octoate, ethylhexyltin, dibutyltin dilaurate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin maleate, dioctyltin diacetate, bismuth isooctanoate, bismuth neodecanoate, zinc isooctanoate, or zirconium isooctanoate.
Preferably, the modified chain extender has a mass content of isocyanate groups of 1 to 25 wt%, such as 3.6 wt%, 3.9 wt%, 4.7 wt%, 4.8 wt%, 4.9 wt%, 6.3 wt%, 5.5 wt%, etc., preferably 1.5 to 15 wt%.
The invention preferably selects the modified chain extender with specific isocyanate group content, and within the range, the modified chain extender has moderate reaction activity, and the content is too low, which can cause the effective functional group content to be reduced, the chain extension reaction speed is slow, and the chain extension efficiency is reduced; the content is too high, the modified chain extender is difficult to achieve the effect mentioned by the invention, and the improvement on the gel point and the crystal point is not obvious.
The second purpose of the present invention is to provide a method for preparing the modified chain extender, which comprises the following steps: and mixing the polyol, the isocyanate and the first catalyst according to the formula ratio, and carrying out polycondensation reaction to obtain the modified chain extender.
Preferably, the polycondensation reaction is carried out until the mass content of isocyanate groups in the modified chain extender is 1 to 25 wt%, such as 3.6 wt%, 3.9 wt%, 4.7 wt%, 4.8 wt%, 4.9 wt%, 6.3 wt%, 5.5 wt%, etc., preferably 1.5 to 15 wt%.
Preferably, the temperature of the polycondensation reaction is 50 to 200 ℃, for example, 80 ℃, 85 ℃, 90 ℃, 95 ℃, etc., preferably 60 to 150 ℃, and more preferably 60 to 120 ℃.
In the invention, the temperature of the polycondensation reaction is preferably in the range of 60-120 ℃, and at the temperature below 120 ℃, isocyanate and polyol are subjected to linear reaction to generate carbamate groups; if the temperature exceeds 120 ℃, isocyanate tends to react with urethane groups to form allophanate, and the presence of allophanate in the modified chain extender adversely affects the subsequent chain extension reaction.
Preferably, the polyol is subjected to a dehydration treatment prior to said mixing.
Wherein the catalyst can be added before the isocyanate is added, or can be added after the isocyanate is added, preferably before the isocyanate is added. The catalyst can be added independently or in the form of solution, or can be dissolved in the polyalcohol in advance, or can be dissolved in the isocyanate in advance.
As a preferred technical scheme of the invention, the preparation method specifically comprises the following steps:
(1) adding the polyol with the formula amount into a reactor for dehydration treatment;
(2) adding a formula amount of a catalyst to the reactor;
(3) adding isocyanate with the formula amount into the reactor, and carrying out polycondensation reaction with the polyol at 50-200 ℃;
(4) and (3) performing the polycondensation reaction until the mass content of the isocyanate group in the modified chain extender is 1-25 wt%, and terminating the reaction to obtain the modified chain extender.
The invention also aims to provide the application of the modified chain extender in the chain extension of the biodegradable polyester.
The biodegradable polyester is polyester with end group of hydroxyl or partial hydroxyl.
Preferably, the biodegradable polyester comprises any one or at least two of polybutylene terephthalate-adipate, polybutylene succinate-adipate, polylactic acid, polycaprolactone or polymethyl ethylene carbonate, and is preferably polybutylene terephthalate-adipate.
The fourth purpose of the invention is to provide a biodegradable polyester, which is prepared by reacting a polyester raw material with the modified chain extender mentioned in one purpose.
Preferably, the polyester raw material comprises any one or at least two of polybutylene terephthalate-adipate, polybutylene succinate-adipate, polylactic acid, polycaprolactone or polymethyl ethylene carbonate, and preferably the polybutylene terephthalate-adipate.
Preferably, the melt index of the polyester raw material is 15-100 g/10min, such as 45g/10min, 50g/10min and the like. The melt index can be effectively reduced by reacting with the modified chain extender, which meets the requirements of blow molding, flow casting or extrusion application.
Preferably, the melt index of the biodegradable polyester is 0.5-10.0 g/10min, such as 1.5g/10min, 2.6g/10min, 3.5g/10min, 3.7g/10min, 5g/10min, etc., preferably 1.0-5.0 g/10 min.
In the present invention, the melt index is measured according to EN ISO1133(190 ℃, 2.16kg weight).
Preferably, the breaking strength of the biodegradable polyester is 20 to 60 MPa.
Preferably, the molar ratio of the isocyanate group in the modified chain extender to the hydroxyl group in the polyester raw material is (0.5-3): 1.
Preferably, the preparation method of the biodegradable polyester comprises the following steps:
adding the modified chain extender of one purpose and a polyester raw material with the melt index of 15-100 g/10min into a reactor, and carrying out chain extension reaction on an isocyanate group in the chain extender and a terminal hydroxyl group of the polyester raw material to obtain the biodegradable polyester with the melt index of 0.5-10.0 g/10 min.
Preferably, the reactor for chain extension reaction of the modified chain extender and the polyester raw material is a single screw extruder, a double screw extruder, a kneader, a static mixer, a dynamic mixer, a BUSS kneader or a List reactor.
The fifth object of the present invention is to provide a film product comprising the biodegradable polyester according to the fourth object.
Preferably, the film product is a biodegradable film.
Compared with the prior art, the invention has the following beneficial effects:
(1) the polyol modified isocyanate chain extender provided by the invention can be well dispersed in the biodegradable polyester, so that the local excess of isocyanate is avoided, the problem that a membrane product forms gel or crystal points is solved, meanwhile, the modified chain extender is not easy to volatilize, the reactivity of the isocyanate chain extender and hydroxyl in the biodegradable polyester is more easily controlled, and the production process is more stable and easier to control.
(2) The invention adopts the isocyanate chain extender modified by the polyalcohol for chain extension of the biodegradable polyester, can effectively reduce the melt index of the polyester and improve the molecular weight, and the biodegradable polyester after chain extension has better mechanical property.
(3) The gel content of the biodegradable polyester provided by the invention is less than 0.1%, and the number of crystal points of a film product is less than 5.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
In the following examples, the gel content was determined by the following method: the surface of the material is wiped clean. 2 samples were taken at different positions and cut into pieces. 2 parallel samples, weighing between 0.25 + -0.05 g, were accurately weighed on a balance (one in ten thousand) and placed in a 200 mesh nickel mesh previously soaked with absolute ethanol for at least 2 hours or more. The mixture was refluxed under heating in a Soxhlet extractor (using chloroform as an extract) for 1 hour, and after the reflux was stopped, the sample in the nickel mesh was immediately taken out and washed with chloroform. Drying for 3 hours in an oven at 100-120 ℃, and taking out. Put into a desiccator, cooled and weighed.
Example 1
This example provides a modified chain extender prepared by using polyester polyol, 1, 4-butanediol adipate diol (PBA), to terminate NCO, and the raw materials for preparing the modified chain extender are shown in the following table:
the preparation method of the modified chain extender comprises the following steps:
adding polyester polyol PBA into a stirring tank, heating to 120 ℃, vacuumizing to remove moisture, then preserving heat at 120 ℃ for 2h, cooling to 80 ℃, adding HDI and a catalyst, introducing nitrogen, reacting at 85 ℃, monitoring NCO until NCO reaches a set value, and finishing the reaction to obtain the modified isocyanate chain extender with the following properties: NCO content 3.6%, solid at 25 ℃.
The embodiment also provides a biodegradable polyester, which is prepared by performing chain extension reaction on the modified chain extender and the biodegradable polyester with the high melt index, and the chain extension reaction is as follows:
adding PBAT with the melt index of 45g/10min into a co-rotating double-screw extruder through a weightless feeding scale, heating the modified chain extender to 80 ℃, metering and feeding the modified chain extender into the extruder through a melt pump, setting the rotating speed of the screw to be 100rpm, completing chain extension reaction in the co-rotating double-screw extruder, and cooling, granulating and drying to obtain the biodegradable polyester PBAT with the low melt index. The melt index of the finished product is measured to be 2.6g/10min, and the gel content is less than 0.1 percent.
This example also provides a film product, which is prepared by the following steps:
the prepared low-melting-index PBAT is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, and the number of crystal points (the diameter is more than 0.2mm) is counted on a glass plate, wherein the number of the crystal points is less than 5.
Example 2
This example provides a modified chain extender with NCO terminated prepared from PBA polyester polyol, where the raw materials for preparing the modified chain extender are shown in the following table:
the preparation method of the modified chain extender comprises the following steps:
adding polyester polyol PBA into a stirring tank, heating to 120 ℃, vacuumizing to remove moisture, then preserving heat at 120 ℃ for 2h, cooling to 80 ℃, adding IPDI and a catalyst, introducing nitrogen, reacting at 90 ℃, monitoring NCO until NCO reaches a set value, and finishing the reaction to obtain a modified isocyanate prepolymer with the following properties: NCO content 3.9%, solid at 25 ℃.
The embodiment also provides a biodegradable polyester, which is prepared by performing chain extension reaction on the modified chain extender and the biodegradable polyester with the high melt index, and the chain extension reaction is as follows:
adding PBAT with the melt index of 45g/10min into a co-rotating double-screw extruder through a weightless feeding scale, heating the modified chain extender prepared in the embodiment 2 to 80 ℃, metering and feeding the modified chain extender into the extruder through a melt pump, setting the rotating speed of a screw to be 100rpm, completing chain extension reaction in the co-rotating double-screw extruder, and cooling, granulating and drying to obtain the biodegradable polyester PBAT with the low melt index. The melt index of the finished product is 3.5g/10min, and the gel content is less than 0.1%.
This example also provides a film product, which is prepared by the following steps:
the prepared low-melting-index PBAT is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, and the number of crystal points (the diameter is more than 0.2mm) is counted on a glass plate, wherein the number of the crystal points is less than 5.
Example 3
The embodiment provides a modified chain extender for preparing an NCO end capping by hydroxyl silicone oil, and the preparation raw materials of the modified chain extender are shown in the following table:
the preparation method of the modified chain extender comprises the following steps:
adding hydroxyl silicone oil into a stirring tank, heating to 120 ℃, vacuumizing to remove moisture, then preserving heat for 2 hours at 120 ℃, cooling to 80 ℃, adding HDI and a catalyst, introducing nitrogen, reacting at 80 ℃, monitoring NCO until NCO reaches a set value, and finishing the reaction to obtain a modified isocyanate prepolymer with the following properties: NCO content 6.3%, viscosity 2000cps at 25 ℃.
The embodiment also provides a biodegradable polyester, which is prepared by performing chain extension reaction on the modified chain extender and the biodegradable polyester with the high melt index, and the chain extension reaction is as follows:
adding PBAT with the melt index of 45g/10min into a co-rotating double-screw extruder through a weightless feeding scale, heating the modified chain extender prepared in the embodiment 3 to 80 ℃, metering and feeding the modified chain extender into the extruder through a melt pump, setting the rotating speed of a screw to be 100rpm, completing chain extension reaction in the co-rotating double-screw extruder, and cooling, granulating and drying to obtain the biodegradable polyester PBAT with the low melt index. The melt index of the finished product is 5.0g/10min, and the gel content is less than 0.1%.
This example also provides a film product, which is prepared by the following steps:
the prepared low-melting-index PBAT is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, and the number of crystal points (the diameter is more than 0.2mm) is counted on a glass plate, wherein the number of the crystal points is less than 5.
Example 4
The embodiment provides a modified chain extender for preparing an NCO end capping by hydroxyl silicone oil, and the preparation raw materials of the modified chain extender are shown in the following table:
the preparation method of the modified chain extender comprises the following steps:
adding hydroxyl silicone oil into a stirring tank, heating to 120 ℃, vacuumizing to remove water, then preserving heat for 2 hours at 120 ℃, cooling to 80 ℃, adding TDI and a catalyst, introducing nitrogen, reacting at 85 ℃, monitoring NCO until NCO reaches a set value, and finishing the reaction to obtain a modified isocyanate prepolymer with the following properties: NCO content 5.3%, viscosity 2500cps at 25 deg.C.
The embodiment also provides a biodegradable polyester, which is prepared by performing chain extension reaction on the modified chain extender and the biodegradable polyester with the high melt index, and the chain extension reaction is as follows:
adding PBS with the melt index of 50g/10min into a co-rotating twin-screw extruder through a weightless feeding scale, metering and feeding the modified chain extender prepared in the embodiment 4 into the extruder through a melt pump, setting the rotating speed of the screw to be 100rpm, completing chain extension reaction in the co-rotating twin-screw extruder, cooling, granulating and drying to obtain the biodegradable polyester PBS with the low melt index. The melt index of the finished product is 1.5g/10min, and the gel content is less than 0.1%.
This example also provides a film product, which is prepared by the following steps:
the prepared low-melting-point PBS is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, the number of crystal points is counted by placing the film on a glass plate, and the number of the crystal points (the diameter is more than 0.2mm) is less than 5.
Example 5
This example provides a modified chain extender with NCO terminated prepared from polyether polyol (polyethylene glycol), where the modified chain extender is prepared from the following raw materials as shown in the following table:
the preparation method of the modified chain extender comprises the following steps:
adding polyethylene glycol into a stirring tank, heating to 120 ℃, vacuumizing to remove water, then preserving heat at 120 ℃ for 2h, cooling to 80 ℃, adding IPDI, introducing nitrogen, reacting at 95 ℃, monitoring NCO until NCO reaches a set value, and finishing the reaction to obtain a modified isocyanate prepolymer with the following properties: the NCO content was 4.8% and it was a white solid at 25 ℃.
The embodiment also provides a biodegradable polyester, which is prepared by performing chain extension reaction on the modified chain extender and the biodegradable polyester with the high melt index, and the chain extension reaction is as follows:
adding PBAT with the melt index of 45g/10min into a co-rotating twin-screw extruder through a weightless feeding scale, metering and feeding the modified chain extender prepared in the embodiment 5 into the extruder through a melt pump, setting the rotating speed of the screw to be 100rpm, completing chain extension reaction in the co-rotating twin-screw extruder, and cooling, granulating and drying to obtain the biodegradable polyester PBAT with the low melt index. The melt index of the finished product is 3.7g/10min, and the gel content is less than 0.1%.
This example also provides a film product, which is prepared by the following steps:
the prepared low-melting-index PBAT is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, and the number of crystal points (the diameter is more than 0.2mm) is counted on a glass plate, wherein the number of the crystal points is less than 5.
Example 6
The embodiment provides a modified chain extender for preparing an NCO end capping based on polyethylene glycol, and the preparation raw materials of the modified chain extender are shown in the following table:
the preparation method of the modified chain extender comprises the following steps:
adding polyethylene glycol into a stirring tank, heating to 120 ℃, vacuumizing to remove water, then preserving heat for 2h at 120 ℃, cooling to 80 ℃, adding TDI and a catalyst, introducing nitrogen, reacting at 90 ℃, monitoring NCO until NCO reaches a set value, and finishing the reaction to obtain a modified isocyanate prepolymer with the following properties: the NCO content was 4.0% and it was a white solid at 25 ℃.
The embodiment also provides a biodegradable polyester, which is prepared by performing chain extension reaction on the modified chain extender and the biodegradable polyester with the high melt index, and the chain extension reaction is as follows:
adding PBAT with the melt index of 45g/10min into a co-rotating twin-screw extruder through a weightless feeding scale, metering and feeding the modified chain extender prepared in the embodiment 6 into the extruder through a melt pump, setting the rotating speed of the screw to be 100rpm, completing chain extension reaction in the co-rotating twin-screw extruder, and cooling, granulating and drying to obtain the biodegradable polyester PBAT with the low melt index. The melt index of the finished product is 3.7g/10min, and the gel content is less than 0.1%.
This example also provides a film product, which is prepared by the following steps:
the prepared low-melting-index PBAT is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, and the number of crystal points (the diameter is more than 0.2mm) is counted on a glass plate, wherein the number of the crystal points is less than 5.
Example 7
This example provides a modified chain extender based on polypropylene glycol for preparing an NCO end cap, where the raw materials for preparing the modified chain extender are shown in the following table:
the preparation method of the modified chain extender comprises the following steps:
adding polypropylene glycol into a stirring tank, heating to 120 ℃, vacuumizing to remove water, then preserving heat at 120 ℃ for 2h, cooling to 80 ℃, adding TDI and trimeric TDI (10:1), introducing nitrogen, reacting at 85 ℃, monitoring NCO until NCO reaches a set value, and finishing the reaction to obtain a modified isocyanate prepolymer with the following properties: NCO content 4.9%, viscosity 6500cps at 25 ℃. Wherein trimeric TDI refers to a trimer of TDI.
The embodiment also provides a biodegradable polyester, which is prepared by performing chain extension reaction on the modified chain extender and the biodegradable polyester with the high melt index, and the chain extension reaction is as follows:
adding PBSA with the melt index of 50g/10min into a co-rotating double-screw extruder through a weightless feeding scale, metering and feeding the modified chain extender prepared in the example 7 into the extruder through a melt pump, setting the rotating speed of the screw to be 100rpm, completing chain extension reaction in the co-rotating double-screw extruder, and cooling, granulating and drying to obtain the biodegradable polyester PBSA with the low melt index. The melt index of the finished product is 3.7g/10min, and the gel content is less than 0.1%.
This example also provides a film product, which is prepared by the following steps:
the prepared low-melting-index PBSA is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, the number of crystal points (the diameter is more than 0.2mm) is counted on a glass plate, and the number of the crystal points is less than 5.
Example 8
This example provides a modified chain extender prepared by using polyester polyol, 1, 4-butanediol adipate diol (PBA), to terminate NCO, and the raw materials for preparing the modified chain extender are shown in the following table:
the preparation method of the modified chain extender comprises the following steps:
adding polyester polyol PBA into a stirring tank, heating to 120 ℃, vacuumizing to remove moisture, then preserving heat at 120 ℃ for 2h, cooling to 80 ℃, adding HDI and a catalyst, introducing nitrogen, reacting at 85 ℃, monitoring NCO until NCO reaches a set value, and finishing the reaction to obtain the modified isocyanate chain extender with the following properties: NCO content was 2.0%, solid at 25 ℃.
The embodiment also provides a biodegradable polyester, which is prepared by performing chain extension reaction on the modified chain extender and the biodegradable polyester with the high melt index, and the chain extension reaction is as follows:
adding PBAT with the melt index of 45g/10min into a co-rotating double-screw extruder through a weightless feeding scale, heating the modified chain extender to 80 ℃, metering and feeding the modified chain extender into the extruder through a melt pump, setting the rotating speed of the screw to be 100rpm, completing chain extension reaction in the co-rotating double-screw extruder, and cooling, granulating and drying to obtain the biodegradable polyester PBAT with the low melt index. The melt index of the finished product is 4.0g/10min, and the gel content is less than 0.1%.
This example also provides a film product, which is prepared by the following steps:
the prepared low-melting-index PBAT is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, and the number of crystal points (the diameter is more than 0.2mm) is counted on a glass plate, wherein the number of the crystal points is less than 5.
Example 9
This example provides a modified chain extender prepared by using polyester polyol, 1, 4-butanediol adipate diol (PBA), to terminate NCO, and the raw materials for preparing the modified chain extender are shown in the following table:
the preparation method of the modified chain extender comprises the following steps:
adding polyester polyol PBA into a stirring tank, heating to 120 ℃, vacuumizing to remove moisture, then preserving heat at 120 ℃ for 2h, cooling to 80 ℃, adding HDI and a catalyst, introducing nitrogen, reacting at 85 ℃, monitoring NCO until NCO reaches a set value, and finishing the reaction to obtain the modified isocyanate chain extender with the following properties: NCO content 12.1%, viscosity 7000cps at 25 ℃.
The embodiment also provides a biodegradable polyester, which is prepared by performing chain extension reaction on the modified chain extender and the biodegradable polyester with the high melt index, and the chain extension reaction is as follows:
adding PBAT with the melt index of 45g/10min into a co-rotating double-screw extruder through a weightless feeding scale, heating the modified chain extender to 80 ℃, metering and feeding the modified chain extender into the extruder through a melt pump, setting the rotating speed of the screw to be 100rpm, completing chain extension reaction in the co-rotating double-screw extruder, and cooling, granulating and drying to obtain the biodegradable polyester PBAT with the low melt index. The melt index of the finished product is 3.9g/10min, and the gel content is less than 0.1%.
This example also provides a film product, which is prepared by the following steps:
the prepared low-melting-index PBAT is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, and the number of crystal points (the diameter is more than 0.2mm) is counted on a glass plate, wherein the number of the crystal points is less than 5.
Example 10
This example provides a modified chain extender prepared by using polyester polyol, 1, 4-butanediol adipate diol (PBA), to terminate NCO, and the raw materials for preparing the modified chain extender are shown in the following table:
the preparation method of the modified chain extender comprises the following steps:
adding polyester polyol PBA into a stirring tank, heating to 120 ℃, vacuumizing to remove moisture, then preserving heat at 120 ℃ for 2h, cooling to 80 ℃, adding HDI and a catalyst, introducing nitrogen, reacting at 120 ℃, monitoring NCO until NCO reaches a set value, and finishing the reaction to obtain the modified isocyanate chain extender with the following properties: NCO content 14.5%, viscosity 6800cps at 25 deg.C.
The embodiment also provides a biodegradable polyester, which is prepared by performing chain extension reaction on the modified chain extender and the biodegradable polyester with the high melt index, and the chain extension reaction is as follows:
adding PBAT with the melt index of 45g/10min into a co-rotating double-screw extruder through a weightless feeding scale, heating the modified chain extender to 80 ℃, metering and feeding the modified chain extender into the extruder through a melt pump, setting the rotating speed of the screw to be 100rpm, completing chain extension reaction in the co-rotating double-screw extruder, and cooling, granulating and drying to obtain the biodegradable polyester PBAT with the low melt index. The melt index of the finished product is 4.5g/10min, and the gel content is less than 0.1%.
This example also provides a film product, which is prepared by the following steps:
the prepared low-melting-index PBAT is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, and the number of crystal points (the diameter is more than 0.2mm) is counted on a glass plate, wherein the number of the crystal points is less than 5.
Example 11
This example provides a modified chain extender capped with NCO prepared from polycarbonate diol, where the raw materials for preparing the modified chain extender are shown in the following table:
the preparation method of the modified chain extender comprises the following steps:
adding polyester polyol PBA into a stirring tank, heating to 120 ℃, vacuumizing to remove moisture, then preserving heat at 120 ℃ for 2h, cooling to 80 ℃, adding HDI and a catalyst, introducing nitrogen, reacting at 60 ℃, monitoring NCO until NCO reaches a set value, and finishing the reaction to obtain the modified isocyanate chain extender with the following properties: the NCO content was 4.9% and the solid was at 25 ℃.
The embodiment also provides a biodegradable polyester, which is prepared by performing chain extension reaction on the modified chain extender and the biodegradable polyester with the high melt index, and the chain extension reaction is as follows:
adding PBAT with the melt index of 45g/10min into a co-rotating double-screw extruder through a weightless feeding scale, heating the modified chain extender to 80 ℃, metering and feeding the modified chain extender into the extruder through a melt pump, setting the rotating speed of the screw to be 100rpm, completing chain extension reaction in the co-rotating double-screw extruder, and cooling, granulating and drying to obtain the biodegradable polyester PBAT with the low melt index. The melt index of the finished product is 3.8g/10min, and the gel content is less than 0.1%.
This example also provides a film product, which is prepared by the following steps:
the prepared low-melting-index PBAT is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, and the number of crystal points (the diameter is more than 0.2mm) is counted on a glass plate, wherein the number of the crystal points is less than 5.
Comparative example 1
The comparative example provides a biodegradable polyester, and HDI is adopted to prepare chain extension PBAT, which specifically comprises the following steps:
adding PBAT with the melt index of 45g/10min into a co-rotating double-screw extruder through a weightless feeding scale, injecting HDI into the double-screw extruder through a liquid metering pump, setting the rotating speed of screws to be 100rpm, completing chain extension reaction in the co-rotating double-screw extruder, and cooling, granulating and drying to obtain the biodegradable polyester PBAT with the low melt index. The melt index of the finished product is measured to be 2.7g/10min, and the gel content is 3.1 per mill.
The prepared low-melting-index PBAT is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, the number of crystal points (the diameter is more than 0.2mm) is counted on a glass plate, and the number of the crystal points is more than 15.
Comparative example 2
The comparative example provides a biodegradable polyester, and HDI is adopted to prepare chain-extended PBS, which specifically comprises the following steps:
adding PBAT with the melt index of 50g/10min into a co-rotating double-screw extruder through a weightless feeding scale, injecting HDI into the double-screw extruder through a liquid metering pump, setting the rotating speed of the screw to be 100rpm, completing chain extension reaction in the co-rotating double-screw extruder, and cooling, granulating and drying to obtain the low-melt-index biodegradable polyester PBSA. The melt index of the finished product is 1.8g/10min, and the gel content is 2.5 per mill.
The prepared low-melting-point PBS is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, the number of crystal points is counted by placing the film on a glass plate, and the number of the crystal points (the diameter is more than 0.2mm) is less than 5.
Comparative example 3
The comparative example provides an NCO-terminated modified chain extender prepared from polyester polyol, 1, 4-butanediol adipate (PBA), and the raw materials for preparing the modified chain extender are shown in the following table:
the preparation method of the modified chain extender comprises the following steps:
adding polyester polyol PBA into a stirring tank, heating to 120 ℃, vacuumizing to remove moisture, then preserving heat at 120 ℃ for 2h, cooling to 80 ℃, adding HDI and a catalyst, introducing nitrogen, reacting at 85 ℃, monitoring NCO until NCO reaches a set value, and finishing the reaction to obtain the modified isocyanate chain extender with the following properties: NCO content 1.4%, solid at 25 ℃.
The comparative example also provides biodegradable polyester, and the chain extension reaction is carried out by adopting the modified chain extender and the biodegradable polyester with high melting index, and the specific steps are as follows:
adding PBAT with the melt index of 45g/10min into a co-rotating double-screw extruder through a weightless feeding scale, heating the modified chain extender to 80 ℃, metering and feeding the modified chain extender into the extruder through a melt pump, setting the rotating speed of the screw to be 100rpm, completing chain extension reaction in the co-rotating double-screw extruder, and cooling, granulating and drying to obtain the biodegradable polyester PBAT with the low melt index. The melt index of the finished product is 15.6g/10min, and the gel content is less than 0.1%.
This comparative example also provides a film product, prepared as follows:
the prepared low-melting-index PBAT is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, and the number of crystal points (the diameter is more than 0.2mm) is counted on a glass plate, and the number of the crystal points is more than 5.
Comparative example 4
The comparative example provides an NCO-terminated modified chain extender prepared from polyester polyol, 1, 4-butanediol adipate (PBA), and the raw materials for preparing the modified chain extender are shown in the following table:
the preparation method of the modified chain extender comprises the following steps:
adding polyester polyol PBA into a stirring tank, heating to 120 ℃, vacuumizing to remove moisture, then preserving heat at 120 ℃ for 2h, cooling to 80 ℃, adding HDI and a catalyst, introducing nitrogen, reacting at 85 ℃, monitoring NCO until NCO reaches a set value, and finishing the reaction to obtain the modified isocyanate chain extender with the following properties: NCO content 13.7%, viscosity 7200cps at 25 ℃.
The comparative example also provides biodegradable polyester, and the chain extension reaction is carried out by adopting the modified chain extender and the biodegradable polyester with high melting index, and the specific steps are as follows:
adding PBAT with the melt index of 45g/10min into a co-rotating double-screw extruder through a weightless feeding scale, heating the modified chain extender to 80 ℃, metering and feeding the modified chain extender into the extruder through a melt pump, setting the rotating speed of the screw to be 100rpm, completing chain extension reaction in the co-rotating double-screw extruder, and cooling, granulating and drying to obtain the biodegradable polyester PBAT with the low melt index. The melt index of the finished product is 3.8g/10min, and the gel content is less than 0.15%.
This comparative example also provides a film product, prepared as follows:
the prepared low-melting-index PBAT is blown on a film blowing machine, the film thickness is 30 mu m after the film is blown, the breadth is 200mm, the film is cut into a shape of 100 multiplied by 100mm, and the number of crystal points (the diameter is more than 0.2mm) is counted on a glass plate, and the number of the crystal points is more than 10.
As can be seen from the above examples and comparative examples, the polyol-modified isocyanate chain extender provided by the present invention is used for chain extension of biodegradable polyester, can effectively reduce the melt index of the product, and improve the problems of gel and crystal point formation in the film product, and meanwhile, the cost is low, and the problem of reduced mechanical strength caused by chain extension of epoxy compounds is not existed.
In addition, the molar ratio of isocyanate to polyol must be controlled within the range of (1.5-5): 1 to obtain the above-mentioned advantageous effects, and the effect is deteriorated when the ratio is smaller (comparative example 3) or larger (comparative example 4).
The present invention is illustrated in detail by the examples described above, but the present invention is not limited to the details described above, i.e., it is not intended that the present invention be implemented by relying on the details described above. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.