CN114426742B - EVOH resin composition and process for producing the same - Google Patents
EVOH resin composition and process for producing the same Download PDFInfo
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- CN114426742B CN114426742B CN202011104215.XA CN202011104215A CN114426742B CN 114426742 B CN114426742 B CN 114426742B CN 202011104215 A CN202011104215 A CN 202011104215A CN 114426742 B CN114426742 B CN 114426742B
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
- C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F210/02—Ethene
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F8/00—Chemical modification by after-treatment
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/24—Acids; Salts thereof
- C08K3/26—Carbonates; Bicarbonates
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/24—Acids; Salts thereof
- C08K3/26—Carbonates; Bicarbonates
- C08K2003/262—Alkali metal carbonates
Abstract
The invention belongs to the technical field of copolymers containing monomers with 4 carbon atoms and only one carbon-carbon double bond, and particularly relates to an EVOH resin composition. The composition comprises ethylene-vinyl alcohol copolymer, potassium salt and sodium salt, and also contains acetic acid. The composition of the present invention can further improve the heat resistance of EVOH resin and can further improve the thermal yellowing resistance of EVOH resin.
Description
Technical Field
The invention belongs to the technical field of copolymers containing monomers with 4 carbon atoms and only one carbon-carbon double bond, and particularly relates to an EVOH resin composition and a preparation method thereof.
Background
EVOH resin (ethylene-vinyl alcohol copolymer) is a crystalline polymer having a chain structure ("ethylene-vinyl alcohol copolymer (EVOH) performance and current state of development", li Jia Ming et al, anhui chemical, vol.45, no. 1, no. 2, on the left column of page 14, no. 2, on the public date 2019, no. 2 and No. 28), and is prepared by hydrolyzing an ethylene-vinyl acetate random copolymer ("chemical engineering dictionary", chemical engineering dictionary editorial, chemical industry Press, no. 1 print on 1 month of 2003, no. 3, no. 1 to No. 3, on the left column of page 2681, no. 12 and No. 31 of 2003).
EVOH resins have excellent aroma-retention barrier properties, transparency and gloss, are resistant to grease, chemicals, ultraviolet rays and other rays, have good mechanical properties, strength and tensile modulus, and are useful as composite packaging films for meat, grease, industrial solvents, agricultural chemicals and the like, foam treatments, hollow containers and barrier layers ("chemical dictionary", chemical dictionary filing committee, chemical industry press, 1 st print in 1 month 2003, 3 rd paragraphs 1 to 13 on page 2681, 12 months and 31 days in 2003). Furthermore, the EVOH resin may be compounded with other materials to form a fire-resistant, antibacterial, and antioxidant material (e.g., "ethylene-vinyl alcohol copolymer (EVOH) performance and current development", plum singing, etc., anhui chemical engineering, vol 45, no. 1, page 14, left column, no. 3, lines 5-6, published 2019, no. 2, month 28).
However, EVOH resins have poor heat resistance, and are liable to cause yellowing of products at high temperatures during processing (usually melt processing), and generate thermal decomposition products, which affect the quality of the products.
At present, this problem is mainly solved by adding additives, for example, in patent document CN105623163A, the thermal stability is improved by adding component B (acid, one or a mixture of inorganic acid or organic carboxylic acid selected from polycarboxylic acid having 2 to 20 carbon atoms), component C (organic phenol or amine compound) in an amount of 0.1 to 4.0% and component D (alkali metal or alkaline earth metal salt) in an amount of 0.1 to 4.0% by mass to a copolymer containing ethylene and vinyl alcohol structural units.
However, this solution has a limited degree of improvement in thermal stability and cannot meet the application requirements of higher processing temperatures.
Disclosure of Invention
In view of the above, an object of the present invention is to provide an EVOH resin composition.
The parts are parts by mass unless otherwise specified.
In order to achieve the purpose, the technical scheme of the invention is as follows:
the ethylene-vinyl alcohol copolymer composition comprises ethylene-vinyl alcohol copolymer, potassium salt and sodium salt, and also contains acetic acid.
Further, the content of the acetic acid is 100-3000ppm relative to the mass of the ethylene-vinyl alcohol copolymer.
Further, the potassium salt comprises potassium carbonate or potassium bicarbonate
Further, the amount of the potassium salt and the sodium salt is 100 to 3000ppm of the total amount of potassium ions contained in the potassium salt and sodium ions contained in the sodium salt relative to the amount of the ethylene-vinyl alcohol copolymer, and the mass ratio of sodium ions contained in the sodium salt to potassium ions contained in the potassium salt is 0.1 to 1.
Further, the ethylene-vinyl alcohol copolymer comprises 100-3000ppm of acetic acid relative to the mass of the ethylene-vinyl alcohol copolymer, and the use amount of potassium salt and sodium salt is 100-3000ppm of the total amount of potassium ions contained in the potassium salt and sodium ions contained in the sodium salt relative to the mass of the ethylene-vinyl alcohol copolymer, and the mass ratio of the sodium ions contained in the sodium salt to the potassium ions contained in the potassium salt is 0.1-1.
The invention also aims to protect the preparation method of the EVOH resin composition, which comprises the following steps:
and carrying out alcoholysis on the ethylene-vinyl acetate copolymer obtained by polymerization by using sodium hydroxide, then carrying out molding granulation, then cleaning, adding acetic acid for washing in the cleaning process, and then adding potassium salt.
Further, the polymerization is carried out by solution polymerization, emulsion polymerization, suspension polymerization or the like.
Further, the polymerization employs solution polymerization.
Further, the solvent used for the polymerization reaction includes an alcohol solvent.
Further, the alcohol solvent includes alcohols having 1 to 4 carbon atoms such as methanol, ethanol, propanol, ethylene glycol, n-butanol and t-butanol, and may be a mixed solvent of the above two alcohols, or may contain other small components with the above alcohols as a main component.
Further, the initiator used for the polymerization includes azo-type initiators or peroxide-type initiators.
Further, azo-type initiators include oil-soluble initiators such as azobisisobutyronitrile, azobisisovaleronitrile, azobisisobutyronitrile, azobiscyclohexanecarbonitrile, dimethyl azobisisobutyrate, and the like.
Further, the peroxide initiator includes organic peroxides (e.g., benzoyl peroxide t-butyl ester, methyl ethyl ketone peroxide, diisobutyryl peroxide, tert-amyl peroxyneodecanoate, bis (4-tert-butylcyclohexyl) peroxydicarbonate, tert-amyl peroxypivalate, tert-butyl peroxyacetate, dibutyl peroxydicarbonate, etc.) or inorganic peroxides (e.g., hydrogen peroxide, ammonium persulfate, potassium persulfate, etc.)
Further, the initiator includes an organic peroxy-based initiator.
Further, the proportioning relation is as follows by mass parts: 10-40 parts of solvent, 60-200 parts of vinyl acetate monomer, 0.01-0.3 part of initiator and 5-60 parts of ethylene monomer.
Further, the mixing ratio in parts by mass is as follows: 10-35 parts of solvent, 80-150 parts of vinyl acetate monomer, 0.03-0.2 part of initiator and 20-40 parts of ethylene monomer.
In the present invention, any method may be used for the alcoholysis.
Further, the content of the acetic acid is 100-3000ppm relative to the mass of the ethylene-vinyl alcohol copolymer.
Further, acetic acid is added in the cleaning process, so that the content of sodium ions in the ethylene-vinyl alcohol copolymer is reduced to 50-2000ppm relative to EVOH, potassium salt is added, the total amount of the sodium ions and the potassium ions in the potassium salt is controlled to be 100-3000ppm relative to the mass of the ethylene-vinyl alcohol copolymer, and the mass ratio of the sodium ions to the potassium ions in the potassium salt is controlled to be 0.1-1.
The invention has the beneficial effects that:
the composition can further improve the heat resistance of the EVOH resin, the initial decomposition temperature can be increased to 350-370 ℃, the maximum decomposition temperature can be increased to 400-420 ℃, and the EVOH resin can meet the process requirement of higher processing temperature.
The method is simple, easy to operate and beneficial to realizing industrial production.
Detailed Description
The examples are provided for better illustration of the present invention, but the present invention is not limited to the examples. Therefore, those skilled in the art can make insubstantial modifications and adaptations to the embodiments described above without departing from the scope of the present invention.
The following detection method of the initial decomposition temperature is as follows: adopting a thermal weight loss analyzer, under the nitrogen atmosphere, heating up at a rate of 10 ℃/min, and heating up to 800 ℃ from room temperature, wherein the temperature when the sample is decomposed by 5% (w) is the initial decomposition temperature.
The following detection method for the maximum decomposition temperature is as follows: adopting a thermal gravimetric analyzer, under the nitrogen atmosphere, increasing the temperature at the rate of 10 ℃/min, increasing the temperature from room temperature to 800 ℃, and obtaining the initial decomposition temperature when the sample is decomposed by 50% (w).
Example 1
The ethylene-vinyl alcohol copolymer composition is prepared by the following steps:
A. polymerization: adding 20 parts of methanol, 150 parts of vinyl acetate and 0.05 part of tert-amyl peroxyneodecanoate into a polymerization kettle with a stirrer, introducing ethylene to keep the pressure in the polymerization kettle at 4.7MPa and the temperature of 60 ℃, reacting for 5 hours to obtain an ethylene-vinyl acetate copolymer solution, and removing ethylene and vinyl acetate monomers by decompression and rectification to obtain the ethylene-vinyl acetate copolymer solution;
B. alcoholysis: b, adjusting the mass fraction of the ethylene-vinyl acetate copolymer solution obtained in the step A to be 25%, then adding a sodium hydroxide-methanol solution (sodium hydroxide is used as a solute) with the concentration of 40g/L for alcoholysis, wherein the use amount of the sodium hydroxide-methanol solution is that the molar ratio of the sodium hydroxide in the sodium hydroxide-methanol solution to the vinyl acetate group contained in the ethylene-vinyl acetate copolymer is 0.05;
C. preparation of the composition: precipitating and separating out an ethylene-vinyl acetate copolymer solution obtained by alcoholysis in an aqueous solution, and cutting the solution into particles by adopting a general cutting-off mode;
then adding water with the mass 5 times of that of the particles to clean the ethylene-vinyl alcohol copolymer particles, washing for 2 hours each time, and repeatedly washing for 2 times;
then, carrying out third washing, adding 0.0008 part by mass of acetic acid relative to the mass of the EVOH (calculated by 1 part by mass) in the third washing process for pickling so as to reduce the content of sodium ions generated by alcoholysis byproducts in the resin to 1400ppm relative to the EVOH;
further, potassium carbonate was added to the resulting EVOH resin so that it contained 1500ppm (relative to EVOH) of potassium ions, followed by drying at 115 ℃ for 24 hours to obtain an EVOH composition.
The initial decomposition temperature of the composition of this example was determined to be 352 ℃ and the maximum decomposition temperature was determined to be 402 ℃.
Example 2
The ethylene-vinyl alcohol copolymer composition is prepared by the following steps:
A. the polymerization process was the same as that of example 1;
B. the alcoholysis process was the same as in example 1;
C. preparation of the composition: precipitating and separating an ethylene-vinyl acetate copolymer solution obtained by alcoholysis in an aqueous solution, and cutting the solution into particles by adopting a general cutting-off mode;
then adding water with the mass 5 times of that of the particles to clean the ethylene-vinyl alcohol copolymer particles, washing for 2 hours each time, and repeatedly washing for 2 times;
then, carrying out third washing, adding acetic acid of 0.0015 part by mass relative to the mass of the EVOH (1 part by mass) in the third washing process for pickling, so that the content of sodium ions generated by alcoholysis byproducts in the resin is reduced to 1200ppm relative to the EVOH;
further, potassium hydrogencarbonate was added thereto so that 1400ppm (relative to EVOH) of potassium ions were contained in the EVOH resin, followed by drying at 115 ℃ for 24 hours to obtain an EVOH composition.
The initial decomposition temperature of the composition of this example was determined to be 362 deg.C and the maximum decomposition temperature was determined to be 408 deg.C.
Example 3
The ethylene-vinyl alcohol copolymer composition is prepared by the following steps:
A. the polymerization process was the same as that of example 1;
B. the alcoholysis process was the same as in example 1;
C. preparation of the composition: precipitating and separating an ethylene-vinyl acetate copolymer solution obtained by alcoholysis in an aqueous solution, and cutting the solution into particles by adopting a general cutting-off mode;
then adding water with the mass 5 times of that of the particles to clean the ethylene-vinyl alcohol copolymer particles, washing for 2 hours each time, and repeatedly washing for 2 times;
then, carrying out third washing, adding acetic acid with the mass of 0.0021 part relative to the mass of the EVOH (calculated by 1 part by mass) in the third washing process for pickling, so that the content of sodium ions generated by alcoholysis byproducts in the resin is reduced to 800ppm relative to the EVOH;
further, potassium dihydrogen phosphate was added to the resulting EVOH resin so that it contained 2000ppm (relative to EVOH) of potassium ions, followed by drying at 115 ℃ for 24 hours to obtain an EVOH composition.
The initial decomposition temperature of the composition of this example was determined to be 368 ℃ and the maximum decomposition temperature was 410 ℃.
Comparative example 1
The ethylene-vinyl alcohol copolymer composition is prepared by the following steps:
A. the polymerization process was the same as in example 1;
B. the alcoholysis process was the same as in example 1;
C. preparation of the composition: precipitating and separating out an ethylene-vinyl acetate copolymer solution obtained by alcoholysis in an aqueous solution, and cutting the solution into particles by adopting a general cutting-off mode;
then adding water with the mass 5 times of that of the particles to clean the ethylene-vinyl alcohol copolymer particles, washing for 2 hours each time, and repeatedly washing for 2 times;
then, carrying out third washing, adding acetic acid of 0.0015 part by mass relative to the mass of the EVOH (1 part by mass) in the third washing process for pickling, so that the content of sodium ions generated by alcoholysis byproducts in the resin is reduced to 1700ppm relative to the EVOH;
further, potassium hydrogencarbonate was added thereto so that 200ppm (relative to EVOH) of potassium ions were contained in the EVOH resin, followed by drying at 115 ℃ for 24 hours to obtain an EVOH composition.
The initial decomposition temperature of the composition of this example was 291 ℃ and the maximum decomposition temperature was 362 ℃.
Comparative example 2
The ethylene-vinyl alcohol copolymer composition is prepared by the following steps:
A. the polymerization process was the same as that of example 1;
B. the alcoholysis process was the same as in example 1;
C. preparation of the composition: precipitating and separating out an ethylene-vinyl acetate copolymer solution obtained by alcoholysis in an aqueous solution, and cutting the solution into particles by adopting a general cutting-off mode;
then adding water with the mass 5 times of that of the particles to clean the ethylene-vinyl alcohol copolymer particles, washing for 2 hours each time, and repeatedly washing for 2 times;
then, carrying out third washing, adding 0.0008 part by mass of acetic acid relative to the mass of the EVOH (calculated by 1 part by mass) in the third washing process for pickling, so that the content of sodium ions generated by alcoholysis byproducts in the resin is reduced to 1700ppm relative to the EVOH;
further, potassium hydrogencarbonate was added thereto so that 500ppm (relative to EVOH) of potassium ions were contained in the EVOH resin, followed by drying at 115 ℃ for 24 hours to obtain an EVOH composition.
The initial decomposition temperature of the composition obtained in this example was found to be 298 ℃ and the maximum decomposition temperature was 367 ℃.
Comparative example 3
The ethylene-vinyl alcohol copolymer composition is prepared by the following steps:
A. the polymerization process was the same as that of example 1;
B. the alcoholysis process was the same as in example 1;
C. preparation of the composition: precipitating and separating an ethylene-vinyl acetate copolymer solution obtained by alcoholysis in an aqueous solution, and cutting the solution into particles by adopting a general cutting-off mode;
then adding water with the mass 5 times of that of the particles to clean the ethylene-vinyl alcohol copolymer particles, washing for 2 hours each time, and repeatedly washing for 2 times;
then, carrying out third washing, adding acetic acid with the mass of 0.0021 part relative to the mass of the EVOH (calculated by 1 part by mass) in the third washing process for pickling, so that the content of sodium ions generated by alcoholysis byproducts in the resin is reduced to 800ppm relative to the EVOH;
further, potassium dihydrogen phosphate was added to the EVOH resin so that the EVOH resin contained 500ppm (relative to the EVOH) of potassium ions, followed by drying at 115 ℃ for 24 hours to obtain an EVOH composition.
The composition of this example was tested to have an initial decomposition temperature of 302 deg.C and a maximum decomposition temperature of 368 deg.C.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (8)
1. An ethylene-vinyl alcohol copolymer composition, characterized by comprising an ethylene-vinyl alcohol copolymer, 100 to 3000ppm of acetic acid relative to the mass of the ethylene-vinyl alcohol copolymer, 100 to 3000ppm of potassium salt and sodium salt relative to the mass of the ethylene-vinyl alcohol copolymer, the total amount of sodium ions contained in the sodium salt and potassium ions contained in the potassium salt being 100 to 3000ppm relative to the mass of the ethylene-vinyl alcohol copolymer, and the mass ratio of the sodium ions contained in the sodium salt to the potassium ions contained in the potassium salt being 0.1.
2. The composition of claim 1, wherein the potassium salt comprises potassium carbonate or potassium bicarbonate.
3. A process for the preparation of a composition according to claim 1 or 2, characterized in that it comprises the following steps:
and (2) carrying out alcoholysis on the ethylene-vinyl acetate copolymer obtained by polymerization by using sodium hydroxide, then carrying out molding granulation, then cleaning, adding acetic acid in the cleaning process, and then adding potassium salt.
4. The method according to claim 3, wherein the content of the acetic acid is 100 to 3000ppm based on the mass of the ethylene-vinyl alcohol copolymer.
5. The production method according to claim 3 or 4, wherein acetic acid is added during the washing to reduce the content of sodium ions in the ethylene-vinyl alcohol copolymer to 50 to 2000ppm relative to EVOH, a potassium salt is added, the total amount of the sodium ions and the potassium ions contained in the potassium salt is controlled to 100 to 3000ppm relative to the mass of the ethylene-vinyl alcohol copolymer, and the mass ratio of the sodium ions to the potassium ions contained in the potassium salt is from 0.1 to 1.
6. The process according to claim 3 or 4, wherein the solvent used in the polymerization reaction comprises an alcohol solvent.
7. The method according to claim 5, wherein the solvent used in the polymerization reaction comprises an alcohol solvent.
8. The method according to claim 3, 4 or 7, wherein the initiator used for the polymerization reaction comprises an azo-type initiator or a peroxide-type initiator.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011104215.XA CN114426742B (en) | 2020-10-15 | 2020-10-15 | EVOH resin composition and process for producing the same |
| PCT/CN2021/123860 WO2022078457A1 (en) | 2020-10-15 | 2021-10-14 | Ethylene-vinyl alcohol copolymer composition, and preparation method therefor |
| EP21879499.8A EP4212585A4 (en) | 2020-10-15 | 2021-10-14 | Ethylene-vinyl alcohol copolymer composition, and preparation method therefor |
| AU2021359535A AU2021359535A1 (en) | 2020-10-15 | 2021-10-14 | Ethylene-vinyl alcohol copolymer composition, and preparation method therefor |
| CN202180069366.2A CN116601223A (en) | 2020-10-15 | 2021-10-14 | Ethylene-vinyl alcohol copolymer composition and method for preparing the same |
| KR1020237016489A KR20230088777A (en) | 2020-10-15 | 2021-10-14 | Ethylene-vinyl alcohol copolymer composition and method for producing the same |
| US18/248,704 US20230416425A1 (en) | 2020-10-15 | 2021-10-14 | Ethylene-vinyl alcohol copolymer composition, and preparation method therefor |
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| CN202011104215.XA CN114426742B (en) | 2020-10-15 | 2020-10-15 | EVOH resin composition and process for producing the same |
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| CN114426742A CN114426742A (en) | 2022-05-03 |
| CN114426742B true CN114426742B (en) | 2023-03-31 |
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| US6838029B2 (en) * | 2001-01-19 | 2005-01-04 | Kuraray Co., Ltd. | Method for producing ethylene-vinyl alcohol copolymer resin |
| JP2005538243A (en) * | 2003-06-20 | 2005-12-15 | 長春石油化學股▲分▼有限公司 | Method for enhancing processing heat resistance of ethylene-vinyl alcohol copolymer |
| JP4564246B2 (en) * | 2003-08-01 | 2010-10-20 | 株式会社クラレ | Resin composition and method for producing the same |
| CA2473520C (en) * | 2003-08-11 | 2012-03-27 | Kuraray Co., Ltd. | Blow molded container and method for producing the same |
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