A nucleating agent, its preparation method and use

Abstract

The application provides a nucleating agent and a preparation method and application thereof. The structure of the nucleating agent is shown in formula I, the nucleating agent belongs to the organic phosphate compound nucleating agent in alpha nucleating agents, contains a benzene ring and a carbon-carbon triple bond, has good thermal stability, ensures that the nucleating agent is not melted and decomposed at the polymer melting point of EVOH in the subsequent application in the preparation of EVOH, and is in the form of microparticles; meanwhile, the para-position of the benzene ring and the carbon-carbon triple bond are connected with polar groups, so that the nucleating agent as a whole shows polarity and can be uniformly dispersed in polar EVOH. Further, the polar group in the carbon-carbon triple bond, i.e. the flexible rotatable functional group in R1, can improve the flexibility of EVOH crystals. The application adds a small amount of the nucleating agent to EVOH, and excellent EVOH with comprehensive performance can be obtained.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of organic synthesis and polymer synthesis, and particularly relates to a nucleating agent and a preparation method and application thereof. BACKGROUND

[0002] Ethylene-vinyl alcohol polymer (EVOH for short) is a chain-like semi-crystalline material with polyethylene flexibility and polyvinyl alcohol barrier property, and is mainly used in the field of flexible packaging. At present, the transparency, oxygen barrier property, mechanical property and thermal stability of EVOH produced in China are poor, which leads to the fact that EVOH cannot be produced industrially and the application range of EVOH is limited. Therefore, it has become an urgent problem to be solved to produce high-quality EVOH and expand the market of EVOH.

[0003] As one of the key factors affecting the quality of EVOH, the research shows that the higher the crystallinity, the more closely the EVOH molecular chains are packed and the less easily the EVOH molecular chains move, so that the gas barrier property and thermodynamic property of EVOH are improved, but the high crystallinity also reduces the flexibility of the material, which limits the application of the prepared EVOH. In order to obtain EVOH with excellent comprehensive performance, domestic and foreign researchers have made great efforts.

[0004] Y. Prykhodko team prepared an ethylene-vinyl acetate polymer (EVA) partial hydrolysis product, i.e. EVA-OH polymer, which has better flexibility than EVOH, but the alcoholysis degree and the content of hydroxyl group of the polymer are low, so the crystallinity is greatly reduced, thereby reducing the thermal stability of the material.

[0005] [P] It is reported that increasing the ethylene content is a common means to improve the flexibility of EVOH. Caroline Maes et al. compared the barrier properties of EVOH with different ethylene contents, and found that the higher the ethylene content, the worse the barrier property of the material. Wang Zijun et al. used polyglycolic acid as an additive to melt blend polyglycolic acid and EVOH to improve the crystallinity of EVOH, but the addition of the additive in a small amount will destroy the crystalline structure of EVOH, resulting in a decrease in the crystallinity. It is found that only when the addition amount of polyglycolic acid is greater than 20 wt%, the crystallinity and flexibility of EVOH can be improved.[ / P] SUMMARY

[0006] Therefore, the purpose of the present application is to provide a nucleating agent and a preparation method and application thereof. The nucleating agent can be applied to the preparation of EVOH to obtain EVOH with excellent comprehensive performance.

[0007] To achieve the above purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a nucleating agent as shown in formula I:

[0009] Formula I;

[0010] wherein R1 is selected from -(CH2) n -OH, -OCO(CH2) m CH3, -(CH2) x -Br, -(CH2) y -F, -CH2OOCH3, -CH2CH2OOCH3, -C((CH3)2(NH2));

[0011] n, m, x, y are independently selected from any integer from 0 to 3;

[0012] R2 and R3 are each independently selected from OH-, -COOH, CH3COO-, -CH2COOH, -CH2NH2, -COCH3, -CH2OH, CH3CONH-, -NH2, -N-(CH3)2 or CH3-O-.

[0013] Preferably, n is 1 or 2, m is 0, 1 or 2; x is 2 or 3; y is 1 or 2.

[0014] Preferably, the nucleating agent is selected from any one of Formula 1 to Formula 3:

[0015] Formula 1; Formula 2; Formula 3.

[0016] In a second aspect, the present application provides a preparation method of the above-mentioned nucleating agent, comprising the following steps:

[0017] reacting a compound shown in Formula A with a compound shown in Formula B in the presence of a solvent to obtain the nucleating agent shown in Formula I;

[0018] Formula A; Formula B;

[0019] Preferably, the solvent is selected from benzene solvents.

[0020] Preferably, the benzene solvents include any one or more of benzene, toluene, xylene, trimethylbenzene or ethylbenzene.

[0021] Preferably, the reaction temperature is 105-130°C and the reaction time is 0.5-5 h.

[0022] In a third aspect, the present application provides an application of the nucleating agent prepared by the above-mentioned preparation method in preparing EVOH.

[0023] In a fourth aspect, the present application provides a preparation method of EVOH, comprising the following steps:

[0024] After mixing the nucleating agent with the EVOH, drying, extruding and granulating, the finished product is obtained.

[0025] Preferably, the mass ratio of the nucleating agent to the EVOH is 1:50-1:100.

[0026] Preferably, the ethylene content in the EVOH is 10-90 wt%.

[0027] Preferably, the mixing time is 5-100 min.

[0028] Preferably, the drying temperature is 60-110℃, and the drying time is 1-24 h.

[0029] Preferably, the extruding temperature is 150-250℃.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] The nucleating agent provided by the present application is an organic phosphate compound nucleating agent in the α nucleating agent, contains a benzene ring and a carbon-carbon triple bond, has good thermal stability, ensures that it does not melt and decompose at the melting point of the EVOH polymer in the subsequent application in the preparation of EVOH, and is in the form of microparticles; at the same time, the para position of the benzene ring and the carbon-carbon triple bond are both connected with a polar group, so that the nucleating agent as a whole shows polarity and can be uniformly dispersed in the polar EVOH. Further, the polar group in the carbon-carbon triple bond, i.e., the flexible rotatable functional group in R1, can improve the flexibility of the EVOH crystalline. In addition, the organic phosphate group has the nature of flame retardation, and the organic phosphate nucleating agent can increase the flame retardance of the EVOH, which is more safe for use on the automobile fuel tank.

[0032] The nucleating agent provided by the present application has a typical esterification reaction in the preparation process, the reactant represented by formula A is acidic, so it is not necessary to additionally add an acid catalyst, the preparation process is simple, the reaction conditions are not harsh, and the requirement for equipment is low.

[0033] In addition, the nucleating agent shown in Formula I can induce the homogeneous nucleation to heterogeneous nucleation when mixed with EVOH and melt-extruded, the heterogeneous nucleation process is increased in the crystallization rate and the free energy required for forming the critical nucleus in the homogeneous nucleation is reduced due to the existence of foreign matters in the EVOH melt. Meanwhile, more crystal nuclei can be formed in the heterogeneous nucleation, the spherulite size is reduced, and the crystallinity and crystallization temperature of EVOH are also improved. In addition, the nucleating agent R2 and R3 are polar groups with hydrogen, which can form hydrogen bonds with the hydroxyl groups in EVOH, so that EVOH and the nucleating agent are combined more closely, so as to achieve the purposes of high nucleation efficiency and fast nucleation rate.

[0034] In summary, the nucleating agent provided by the present application has a small addition amount and a wide application range, and can be applied to EVOH with an ethylene content of 10-90 wt%, and the obtained EVOH has excellent comprehensive performance. DETAILED DESCRIPTION

[0035] The technical solutions of the present application will be described clearly and completely in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0036] At present, the EVOH prepared in the prior art is difficult to simultaneously achieve the requirements of thermal stability and flexibility, therefore, the present application aims to develop a nucleating agent to perfect the crystallization of EVOH, optimize the gas barrier property, mechanical property, thermodynamic property and haze of EVOH, and at the same time, take into account the flexibility to improve the processability of EVOH and expand the application range of EVOH.

[0037] Based on this, the present application provides a nucleating agent as shown in Formula I:

[0038] Formula I;

[0039] In the present application, R1 is a polar group with a rotatable bond, which can be specifically selected from -(CH2) n -OH, -OCO(CH2) m CH3, -(CH2) x -Br, -(CH2) y -F, -CH2OOCH3, -CH2CH2OOCH3, -C((CH3)2(NH2));

[0040] wherein n, m, x and y are independently selected from any integer from 0 to 3, and can be specifically selected from 0, 1, 2 or 3.

[0041] In the present application, R2 and R3 are both hydrogen-bearing polar groups, each independently selected from OH-, -COOH, CH3COO-, -CH2COOH, -CH2NH2, -COCH3, -CH2OH, CH3CONH-, -NH2, -N-(CH3)2 or CH3-O-.

[0042] In some preferred embodiments of the present application, the nucleating agent has a structure shown in Formula I, wherein n is preferably 1 or 2, m is preferably 0, 1 or 2; x is preferably 2 or 3; and y is preferably 1 or 2.

[0043] Further, in some preferred embodiments of the present application, the nucleating agent has a structure shown in Formula I, wherein R1 is selected from -(CH2)2-OH, -OCOCH3, -(CH2)2-Br, -(CH2)2-F, -CH2OOCH3, -CH2CH2OOCH3, -C((CH3)2(NH2)).

[0044] In some specific embodiments of the present application, the nucleating agent is selected from any one of the following Formula 1-Formula 3:

[0045] Formula 1; Formula 2; Formula 3.

[0046] The present application provides the above-mentioned nucleating agent shown in Formula I, which belongs to the organic phosphate compound class of nucleating agents in α nucleating agents, contains a benzene ring and a carbon-carbon triple bond, has good thermal stability, ensures that it does not melt and decompose at the polymer melting point of EVOH in the subsequent application in the preparation of EVOH, and is in the form of microparticles; at the same time, the para position of the benzene ring and the carbon-carbon triple bond are both connected with polar groups, so that the nucleating agent as a whole exhibits polarity and can be uniformly dispersed in polar EVOH. Further, the polar group in the carbon-carbon triple bond, i.e., R1 contains a flexible rotatable functional group, which can improve the flexibility of EVOH crystals.

[0047] The present application also provides a preparation method of the above-mentioned nucleating agent, which comprises the following steps:

[0048] reacting a compound shown in Formula A with a compound shown in Formula B in the presence of a solvent to obtain the nucleating agent shown in Formula I;

[0049] Formula A; Formula B.

[0050] Specifically, in some embodiments of the present application, Formula A comprises one or more of Formula 4-Formula 6; and Formula B comprises a compound shown in Formula 7:

[0051]

[0052] Formula 4 Formula 5 Formula 6

[0053]

[0054] Formula 7.

[0055] According to the present application, the compound shown as Formula A is reacted with the compound shown as Formula B in the presence of a solvent to obtain the nucleating agent shown as Formula I. In the present application, the solvent is preferably a benzene solvent; the benzene solvent includes any one or more of benzene, toluene, xylene, trimethylbenzene or ethylbenzene. The mass ratio of the compound shown as Formula A to the compound shown as Formula B is generally 1:1, and can be appropriately adjusted, such as 1.1:1, 1.2:1, 1:1.1, 1:1.2, etc. The amount of the solvent added is 200 mL. The reaction temperature is 105-130°C, preferably 110-120°C; the time is 0.5-5 h, preferably 1-4 h.

[0056] In some embodiments of the present application, the compound shown as Formula A and the compound shown as Formula B are preferably added to a reaction bottle in proportion, stirred, and an appropriate amount of benzene solvent is added, and stirring is continued until uniform, and heated to 105-130°C reflux for 20-36 h.

[0057] Exemplarily, the synthesis route of the nucleating agent shown as Formula I above can be represented as follows:

[0058] .

[0059] In some embodiments of the present application, after the above reaction is completed, the benzene solvent is removed by rotary evaporation to obtain a solid, the solid is washed with deionized water for 2-3 times, suction filtered, the solid is collected and dried at 110°C for 24 h to obtain the dried nucleating agent.

[0060] As a preferred technical solution, the reactor involved in the above reaction, including reaction bottles, Buchner funnels, rotary evaporation systems, etc. must be clean, dry and flushed with nitrogen, and the solvent needs to be dehydrated to avoid hydrolysis of the nucleating agent and cause structural damage.

[0061] The above-mentioned compound shown as Formula A, the compound shown as Formula B and the solvent can all be commercially available products.

[0062] The nucleating agent provided by the application is prepared by the reaction of the hydroxyl group of the phosphoric acid group in the compound shown in formula A with the hydrogen of the hydroxyl group in the compound shown in formula B, which belongs to a typical esterification reaction. Moreover, the reactant shown in formula A is acidic, so it is unnecessary to additionally add an acid catalyst, the preparation process is simple, the reaction condition is not harsh, the requirement for equipment is low, and large-scale production or industrialized production can be easily realized.

[0063] The application also provides application of the nucleating agent related to the technical solution to preparation of EVOH.

[0064] Specifically, the application provides a preparation method of EVOH, which comprises the following steps:

[0065] After the nucleating agent is mixed with the EVOH, drying, extrusion and granulation are performed to obtain a finished product.

[0066] In the application, the nucleating agent and the EVOH are mixed at a mass ratio of 1:50 to 1:100, preferably 1:60 to 1:90, the mixing is preferably performed in a high-speed mixer, the mixing time is 5 to 100 min, preferably 10 to 80 min, and more preferably 30 to 60 min, and after the nucleating agent and the EVOH are uniformly mixed, the obtained mixture is dried at 60 to 110 DEG C for 1 to 24 h, and preferably dried at 80 to 100 DEG C for 10 to 24 h.

[0067] Then, according to the application, the mixture is extruded and granulated to obtain a finished product. In the application, the extrusion and granulation are preferably performed in a double-screw extruder, the extrusion temperature is 150 to 250 DEG C, preferably 180 to 220 DEG C, and the screw rotation speed of the double-screw extruder is 50 to 200 r / min, preferably 80 to 150 r / min.

[0068] It should be noted that the mass ratio of the nucleating agent to the EVOH is 1:50 to 1:100, so the amount of the nucleating agent added is small. In addition, the ethylene content in the EVOH ranges from 10 to 90 wt%, preferably 20 to 80 wt%, so the range of use of the nucleating agent is wide. Further, it is tested that the comprehensive performance of the obtained EVOH is excellent. Therefore, the nucleating agent provided by the application solves the problems in the preparation of EVOH.

[0069] The preparation method of the EVOH is not particularly limited in the application, and can be performed according to the technical means well known to those skilled in the art.

[0070] Exemplarily, the preparation method of the EVOH comprises the following steps:

[0071] (1) free radical polymerization of ethylene and vinyl acetate (abbreviated as VAc) to prepare EVA

[0072] Specific steps: under the protection of high-purity N2, VAc, initiator, solvent are mixed in a certain proportion, and the clear solution is transferred into a reaction kettle with a polytetrafluoroethylene lining, and a certain pressure of ethylene is filled, after the pressure is stable, the circulating pump is started to heat, until the target polymerization temperature, start timing, after a period of polymerization, take out the material body while hot, vacuum drying at 60℃ for 24h, remove the volatile matter, get transparent EVA elastomer, for use.

[0073] The reactor involved, including the lining of the reaction kettle, must be clean, dry and flushed with nitrogen; VAc is removed by vacuum distillation to remove the polymerization inhibitor and stored at 10℃ in a sealed container; the initiator is purified by recrystallization, vacuum drying, light shielding, and stored at 10℃ in a sealed container. The solvent needs to be dehydrated by molecular sieve. The initiator can be selected from azo initiator, peroxide compound initiator, and organic or inorganic initiator, specifically including any one or more of azobisisobutyronitrile (AIBN), azobisisoheptyl nitrile (ABVN), dibenzoyl peroxide (BPO), diethylhexyl peroxide (EHP), potassium persulfate, ammonium persulfate or hydrogen peroxide. The solvent includes any one or more of diethyl ether, methanol, ethanol, tert-butyl alcohol, dimethyl carbonate (DMC), tetrahydrofuran, petroleum ether, acetone or hexane.

[0074] In some embodiments of the present application, the ratio of VAc, initiator, solvent (V:m:V) is (1-100):(1-100):(1-100), preferably (1-40):(1-30):(1-50), specifically 30:10:50, 20:20:60, 10:30:60 or 40:10:50, etc. Wherein, V represents volume, unit is mL, m represents mass, unit is g; ethylene pressure is 0.01-10 MPa, preferably 0.1-5 MPa; polymerization temperature is 60-100℃, preferably 70-90℃; polymerization time is 0.5-10 h, preferably 2-8 h. The ethylene, VAc, solvent, initiator involved are all from the market.

[0075] The substances involved in the above scheme and their proportions, temperature, pressure, time can be adjusted as needed, to avoid being tedious, will not be repeated.

[0076] (2) Preparation of EVOH by alcoholysis of EVA

[0077] Specific steps: the EVA, basic catalyst, solvent obtained in step (1) are mixed in a three-necked flask according to a certain proportion, and after alcoholysis at a certain temperature for a period of time, a certain concentration of acid solution is added dropwise into the mixed solution, the solvent is the same as the solvent used for alcoholysis, the reaction is neutralized until pH = 7, and finally the reaction is transferred to cold water, filtered, the filter cake is washed with anhydrous ethanol three times, the excess water is removed, and the filter cake is vacuum dried at 100℃ overnight to obtain the final product EVOH, which is stored and used.

[0078] The reactors involved, including reaction bottles and Buchner funnels, must be clean, dry and flushed with nitrogen. The solvent needs to be dehydrated. The solvent includes any one or more of ethyl ether, methanol, ethanol, tert-butyl alcohol, dimethyl carbonate (DMC), tetrahydrofuran, petroleum ether, acetone or hexane. The basic catalyst includes any one or more of sodium hydroxide, potassium hydroxide, sodium ethoxide, calcium hydroxide, sodium carbonate or potassium bicarbonate. The proportion of EVA, basic catalyst and solvent (m:m:V) is (1-10):(1-10):(1-10), preferably (1-4):(1-3):(1-5), and specifically 4:1:5, 3:2:5, 2:3:5 or 4:1:5, etc. V represents volume in mL, and m represents mass in g. The alcoholysis temperature is 40-80℃, preferably 50-60℃; the alcoholysis time is 0.5-10 h, preferably 2-6 h. The concentration of the acid solution is 0.01-10 mol / L, preferably 0.1-8 mol / L. The solute in the acid solution includes any one or more of organic acids and inorganic acids, specifically selected from acetic acid, boric acid and hydrochloric acid. The solvent of the acid solution includes any one or more of ethyl ether, methanol, ethanol, tert-butyl alcohol, dimethyl carbonate (DMC), tetrahydrofuran, petroleum ether, acetone or hexane. It should be noted that the above-mentioned solvents, acid solutions, anhydrous ethanol, basic catalysts, etc. are all commercially available.

[0079] The substances involved in the above scheme, their proportions, temperatures, pressures and times can be adjusted as needed, and will not be described in detail to avoid complexity.

[0080] In order to further illustrate the present application, the following examples are used for detailed description. The experimental materials used in the following examples of the present application are all commercially available. The "V" mentioned below represents volume in mL, and "m" represents mass in g. Example 1

[0081] Into a reaction flask, 1.14 g of acetylenedicarboxylic acid dimethyl ester and 2.21 g of 4-hydroxyphenoxy-4-hydroxyphenyl-phosphonic acid were added, stirred, and 200 mL of toluene was added, and stirred until uniform, heated to 110°C and refluxed for 2 h, and the toluene was removed by rotary evaporation to obtain a solid, which was washed with deionized water for 3 times, suction filtered, and the solid was collected and dried at 110°C for 24 h to obtain 4-hydroxyphenoxy-4-hydroxyphenyl-3-acetylenedicarboxylic acid dimethyl ester phosphonate nucleating agent (the structural formula is shown as Formula 1), which was sealed and stored for later use.

[0082] Under the protection of high-purity N2, VAc, AIBN, and anhydrous methanol were mixed in a ratio of 30:10:50 (V:m:V), and the clear solution was transferred into a reaction kettle with a polytetrafluoroethylene liner, and 3 MPa of ethylene was filled. After the pressure stabilized, the circulating pump was started and heated, and the polymerization temperature was 60°C. After polymerization for 2 h, the material was taken out while hot, and vacuum dried at 60°C for 24 h to remove the volatile components, to obtain a transparent EVA elastomer, which was stored for later use and testing.

[0083] EVA, sodium hydroxide, and methanol were mixed in a ratio of 4:1:5 (m:m:V) in a three-necked flask, and after alcoholysis at 65°C for 2 h, 1 mol / L acetic acid / methanol solution was added dropwise to the mixed solution, and the reaction was neutralized until pH=7. Finally, the reaction was transferred to cold water, and then washed with anhydrous ethanol for 3 times to remove excess water, and dried at 100°C overnight to obtain EVOH, which was stored for later use.

[0084] The above-mentioned 4-hydroxyphenoxy-4-hydroxyphenyl-3-acetylenedicarboxylic acid dimethyl ester phosphonate nucleating agent and EVOH were mixed in a high-speed mixer at a mass ratio of 1:100 for 60 min, dried at 110°C for 24 h, and then the mixture was put into a co-rotating twin-screw extruder, with an extrusion temperature of 220°C and a screw rotation speed of 150 r / min, and dried at 110°C for 24 h to obtain EVOH doped with a small amount of nucleating agent, which was the final product. Example 2

[0085] Into a reaction flask, 1.14 g of acetylenedicarboxylic acid dimethyl ester and 1.20 g of 4-aminophenoxy-4-aminophenyl-phosphonic acid were added, stirred, and 200 mL of benzene solvent was added, and stirred until uniform, heated to 110°C and refluxed for 2 h, and the toluene was removed by rotary evaporation to obtain a solid, which was washed with deionized water for 3 times, suction filtered, and the solid was collected and dried at 110°C for 24 h to obtain 4-aminophenoxy-4-aminophenyl-3-acetylenedicarboxylic acid dimethyl ester phosphonate nucleating agent (the structural formula is shown as Formula 2), which was sealed and stored for later use.

[0086] Under the protection of high-purity N2, VAc, AIBN, and anhydrous methanol were mixed in a ratio of 30:10:50 (V:m:V), and the clear solution was transferred into a reaction kettle with a polytetrafluoroethylene lining and filled with 3 MPa of ethylene. After the pressure stabilized, the circulating pump was turned on for heating, and the polymerization temperature was 60°C. After 2 h of polymerization, the material was taken out while hot, and vacuum dried at 60°C for 24 h to remove the volatile components, obtaining a transparent EVA elastomer, which was reserved and tested.

[0087] EVA, sodium hydroxide, and methanol were mixed in a ratio of 4:1:5 (m:m:V) in a three-necked flask, and after alcoholysis at 65°C for 2 h, 1 mol / L acetic acid / methanol solution was added dropwise to the mixed solution to neutralize the reactants until pH=7. Finally, the reactants were transferred to cold water and washed with anhydrous ethanol three times to remove excess water, and dried at 100°C overnight to obtain EVOH, which was reserved.

[0088] The above-mentioned 4-aminophenoxy-4-aminophenyl-3-ethynyl dimethyl ester nucleating agent was mixed with EVOH in a mass ratio of 1:100 in a high-speed mixer for 60 min, dried at 110°C for 24 h, and then the mixture was put into a co-rotating twin-screw extruder, with an extrusion temperature of 220°C and a screw speed of 150 r / min. The mixture was dried at 110°C for 24 h to obtain EVOH doped with a small amount of nucleating agent, which was the final product. Example 3

[0089] 1.14 g of ethynyl dimethyl ester dimethanol and 1.20 g of 4-methoxyphenoxy-4-methoxyphenyl-phosphoric acid were added to a reaction bottle, stirred, and 200 mL of benzene solvent was added. After uniform stirring, heating was performed to 110°C for reflux for 2 h, and toluene was removed by rotary evaporation to obtain a solid. The solid was washed with deionized water three times, suction filtered, and the solid was collected and dried at 110°C for 24 h to obtain 4-methoxyphenoxy-4-methoxyphenyl-3-ethynyl dimethyl ester nucleating agent (the structural formula is shown as formula 3), which was sealed and reserved.

[0090] Under the protection of high-purity N2, VAc, AIBN, and anhydrous methanol were mixed in a ratio of 30:10:50 (V:m:V), and the clear solution was transferred into a reaction kettle with a polytetrafluoroethylene lining and filled with 3 MPa of ethylene. After the pressure stabilized, the circulating pump was turned on for heating, and the polymerization temperature was 60°C. After 2 h of polymerization, the material was taken out while hot, and vacuum dried at 60°C for 24 h to remove the volatile components, obtaining a transparent EVA elastomer, which was reserved and tested.

[0091] EVA, sodium hydroxide, methanol were mixed in a three-necked flask according to the ratio of 4:1:5 (m:m:V) and stirred uniformly. After alcoholysis at 65°C for 2 h, 1 mol / L acetic acid / methanol solution was added dropwise into the mixed solution to neutralize the reactants until pH=7. Finally, the reactants were transferred into cold water and washed with anhydrous ethanol for 3 times to remove the excess water. The EVOH was obtained by drying at 100°C overnight and was reserved for later use.

[0092] The 4-methoxyphenoxy-4-methoxyphenyl-3-acetylenedicarboxylate nucleating agent and EVOH were mixed in a high-speed mixer according to the mass ratio of 1:100 for 60 min. The mixture was dried at 110°C for 24 h and then put into a co-rotating twin-screw extruder. The extrusion temperature was 220°C and the screw rotation speed was 150 r / min. The mixture was dried at 110°C for 24 h to obtain EVOH doped with a small amount of nucleating agent, which was the final product. Example 4

[0093] 1.14 g of acetylenedicarboxylate dimethyl alcohol and 1.20 g of 4-hydroxyphenoxy-4-hydroxyphenyl-phosphoric acid were added into a reaction flask, stirred, and 200 mL of benzene solvent was added. After uniform stirring, the mixture was heated to 110°C and refluxed for 2 h. Toluene was removed by rotary evaporation to obtain a solid. The solid was washed with deionized water for 3 times, suction filtered, and the solid was collected and dried at 110°C for 24 h to obtain 4-hydroxyphenoxy-4-hydroxyphenyl-3-acetylenedicarboxylate nucleating agent (the structural formula is shown as formula 1), which was sealed and reserved for later use.

[0094] Under the protection of high-purity N2, VAc, AIBN, and anhydrous methanol were mixed uniformly according to the ratio of 30:10:50 (V:m:V). The clear solution was transferred into a reaction kettle with a polytetrafluoroethylene liner, and 3 MPa of ethylene was filled. After the pressure stabilized, the circulation pump was started to heat. The polymerization temperature was 60°C, and the polymerization was carried out for 2 h. After that, the material was taken out while hot and dried at 60°C under vacuum for 24 h to remove the volatile components, thereby obtaining a transparent EVA elastomer, which was reserved for later use and testing.

[0095] EVA, sodium hydroxide, methanol were mixed in a three-necked flask according to the ratio of 4:1:5 (m:m:V) and stirred uniformly. After alcoholysis at 65°C for 2 h, 1 mol / L acetic acid / methanol solution was added dropwise into the mixed solution to neutralize the reactants until pH=7. Finally, the reactants were transferred into cold water and washed with anhydrous ethanol for 3 times to remove the excess water. The EVOH was obtained by drying at 100°C overnight and was reserved for later use.

[0096] The 4-methoxyphenoxy-4-methoxyphenyl-3-acetylenic dimethyl ester phosphonate nucleating agent and EVOH were mixed in a high-speed mixer at a mass ratio of 1:75, the mixing time was 60 min, dried at 110°C for 24 h, and then the mixture was put into a co-rotating twin-screw extruder, the extrusion temperature was 220°C, the screw rotation speed was 150 r / min, and dried at 110°C for 24 h to obtain EVOH doped with a small amount of nucleating agent, which was the final product. Example 5

[0097] 1.14 g of acetylenic dimethyl ester dimethanol and 1.20 g of 4-methoxyphenoxy-4-methoxyphenyl-phosphonic acid were added to a reaction bottle, stirred, 200 mL of benzene solvent was added, and stirred until uniform, heated to 110°C and refluxed for 2 h, toluene was removed by rotary evaporation, and a solid was obtained, which was washed with deionized water for 3 times, suction filtered, the solid was collected and dried at 110°C for 24 h to obtain 4-methoxyphenoxy-4-methoxyphenyl-3-acetylenic dimethyl ester phosphonate nucleating agent (the structural formula is shown as formula 3), which was sealed and stored for later use.

[0098] Under the protection of high-purity N2, VAc, AIBN and anhydrous methanol were mixed in a ratio of 30:10:50 (V:m:V), the clear solution was transferred into a reaction kettle with a polytetrafluoroethylene liner, and 3 MPa of ethylene was filled, after the pressure was stable, the circulation pump was started and heated, the polymerization temperature was 60°C, after 2 h of polymerization, the material was taken out while hot, and vacuum dried at 60°C for 24 h to remove the volatile components, to obtain a transparent EVA elastomer, which was stored for later use and testing.

[0099] EVA, sodium hydroxide and methanol were stirred and mixed in a three-necked flask at a ratio of 4:1:5 (m:m:V), and after alcoholysis at 65°C for 2 h, 1 mol / L acetic acid / methanol solution was added dropwise to the mixed solution, and the reaction was neutralized until pH=7, and then the reaction was transferred to cold water, washed with anhydrous ethanol for 3 times, and the excess water was removed, and dried at 100°C overnight to obtain EVOH, which was stored for later use.

[0100] The 4-methoxyphenoxy-4-methoxyphenyl-3-acetylenic dimethyl ester phosphonate nucleating agent and EVOH were mixed in a high-speed mixer at a mass ratio of 1:75, the mixing time was 60 min, dried at 110°C for 24 h, and then the mixture was put into a co-rotating twin-screw extruder, the extrusion temperature was 220°C, the screw rotation speed was 150 r / min, and dried at 110°C for 24 h to obtain EVOH doped with a small amount of nucleating agent, which was the final product.

[0101] Comparative Example 1

[0102] Under the protection of high-purity N2, VAc, AIBN and anhydrous methanol were mixed in a ratio of 30:10:50 (V: m:V). The clarified solution was transferred into a reactor lined with polytetrafluoroethylene and filled with 3 MPa of ethylene. After the pressure stabilized, the circulating pump was turned on for heating. The polymerization temperature was 60°C. After polymerization for 2 h, the material was taken out while hot and vacuum dried at 60°C for 24 h to remove volatiles to obtain a transparent EVA elastomer, which was retained and tested.

[0103] EVA, NaOH, and methanol were stirred and mixed in a three-necked flask at a ratio of 4:1:5 (m:m:V), and after alcoholysis at 65°C for 2 hours, 1 mol / L acetic acid / methanol solution was added dropwise to the mixed solution to neutralize the reactants until the pH was 7. Finally, the reactants were transferred to cold water and washed three times with water to remove water-soluble impurities in the solution. Then, the reactants were washed three times with anhydrous ethanol to remove excess water, and dried at 100°C overnight to obtain the final product EVOH, which was retained and tested.

[0104] Performance Testing

[0105] The test method is as follows:

[0106] GPC was used to test Mn and PDI. The test method was as follows: 1 mL of DMF and 2 mg of EVOH were dissolved at 65°C for 1 h to obtain a clear solution. Mn and PDI were tested using a Waters GPC 1515 at a test temperature of 30°C, DMF as the mobile phase, and a flow rate of 1.0 mL / min. Polystyrene was used to obtain a standard curve.

[0107] DSC test T m 、T c 、T g The test method is as follows: 5 mg of EVOH sample is placed in an aluminum pan and heated in a nitrogen atmosphere (50 mL

[0108] / min), from 25℃ to 200℃, and keep it at 200℃ for 30min, with a heating rate of 10℃ / min. This stage is the first stage, the purpose of which is to eliminate the thermal history of the material. It is then cooled naturally to room temperature, which is the second stage to measure T c Finally, the temperature rises from room temperature to 200℃, which is the third stage. T g and T m , equipment model: METTLER TOLEDO.

[0109] Nuclear magnetic resonance spectroscopy (NMR) test of alcoholysis degree: tested using BRUKER AVANCE 400M 1H spectrum, tetramethylsilane as internal standard (δ = 0.0 ppm), 10 mg EVOH was dissolved in 1 mL DMSO-d6 at 85 ° C until a clear solution was obtained, and the solution was injected into a quartz tube for testing. The obtained H spectrum was analyzed and the peak area of ​​δ = 3.5~3.8 ppm (-OH group after VAC alcoholysis) was integrated to obtain I (VOH) , integrate the peak area of ​​δ = 2.0 ppm (-CH3 in VAC) to obtain I (V-CH3) , alcoholysis degree = I (VOH) *100% / ( I (VOH) + I (V-CH3) ).

[0110] Brugger GTT gas transmission rate tester using differential pressure method to test oxygen transmission rate, test standard: GB / T 1038, temperature: 23°C, relative humidity: 51%, test area: 5 cm 2 , test thickness 80 μm.

[0111] Universal testing machine tests impact strength, tensile strength, and elongation at break. Test standard: GB / T 1040.1-2006. Spline injection molding conditions: GB / T 17037.1.

[0112] Haze, test reference standard GB T 2410-2008.

[0113] The test results are shown in Tables 1 and 2 below:

[0114] Table 1 Comparison of basic properties of EVOH

[0115]

[0116] Table 2 Comparison of EVOH mechanical properties

[0117]

[0118] The terms mentioned in Table 1 and Table 2 above are explained as follows:

[0119] 1. Number average molecular weight (Mn): The molecular weight is measured based on the number fraction. The number average molecular weight is equal to the molecular weight of each component multiplied by the mole fraction of each component.

[0120] 2. Polydispersity Index (PDI): The molecular weight distribution of the polymer. The larger the PDI, the wider the molecular weight distribution; the smaller the PDI, the more uniform the molecular weight distribution;

[0121] 3. Crystallization temperature (T c ): refers to the temperature required for a substance to transform from a liquid to a crystal;

[0122] 4. Melting temperature (Tm ) : temperature at which melting occurs;

[0123] 5. Glass transition temperature (Tg) : temperature at which the glass state is changed to the high-elastic state; g ) : temperature at which the glass state is changed to the high-elastic state;

[0124] 6. Alcoholysis degree: percentage of hydroxyl group in the product obtained after alcoholysis with respect to the original group;

[0125] 7. Oxygen transmission rate (O2GTR) : volume of oxygen per unit area per unit time, which is transmitted through a material such as a plastic film at a constant temperature and unit pressure difference at the time of stable transmission;

[0126] 8. Impact strength: index reflecting the impact resistance (brittleness, degree of toughness) of a material;

[0127] 9. Tensile strength: maximum stress value of a material before being broken;

[0128] 10. Elongation at break: displacement value of a test sample at the time of breakage with respect to the original length, which is expressed in percentage (%);

[0129] 11. Crystallinity: percentage (%) of a crystalline region in a polymer, and the higher the crystallinity, the more regular the arrangement of molecular chains and the higher the melting point;

[0130] 12. Haze: percentage (%) of transmitted light intensity deviated by more than 2.5° with respect to incident light, and the greater the haze, the lower the gloss and transparency of a film.

[0131] As can be seen from the data of Tables 1 and 2, the addition of the nucleating agent does not greatly affect the molecular weight of EVOH, but since the nucleating agent can make the formed crystal grains finer, the haze and mechanical properties of EVOH are significantly improved, and the nucleating agent can also increase the crystallinity of EVOH, thereby significantly reducing the oxygen transmission rate and greatly improving the barrier property.

[0132] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A nucleating agent as shown in Formula I: Formula I; in, R1 is selected from -(CH2) n -OH, -OCO(CH2) m CH3, -(CH2) x -Br, -(CH2) y -F, -CH2OOCH3, -CH2CH2OOCH3, -C((CH3)2(NH2)); n, m, x, and y are independently selected from any integer between 0 and 3; R2 and R3 are each independently selected from OH-, -COOH, CH3COO-, -CH2COOH, -CH2NH2, -COCH3, -CH2OH, CH3CONH-, -NH2, -N-(CH3)2 or CH3-O-.

2. The nucleating agent according to claim 1, characterized in that The n is 1 or 2; the m is 0, 1 or 2; the x is 2 or 3; and the y is 1 or 2.

3. The nucleating agent according to claim 1 or 2, characterized in that The nucleating agent is selected from any one of the following formulas 1 to 3: Formula 1; Formula 2; Formula 3.

4. A method for preparing a nucleating agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: The compound represented by formula A is reacted with the compound represented by formula B in the presence of a solvent to obtain a nucleating agent represented by formula I; Formula A; Formula B.

5. The preparation method according to claim 4, characterized in that The solvent is selected from benzene solvents; The benzene solvent includes any one or more of benzene, toluene, xylene, trimethylbenzene or ethylbenzene.

6. The preparation method according to claim 4 or 5, characterized in that The reaction temperature is 105-130° C. and the reaction time is 0.5-5 h.

7. Use of the nucleating agent according to any one of claims 1 to 3 or the nucleating agent prepared by the preparation method according to any one of claims 4 to 6 in the preparation of EVOH.

8. A method for preparing EVOH, characterized in that: The following steps are involved: After mixing the nucleating agent with EVOH, drying, extruding and granulating to obtain the finished product; The nucleating agent is the nucleating agent according to any one of claims 1 to 3 or the nucleating agent prepared by the preparation method according to any one of claims 4 to 6.

9. The preparation method according to claim 8, characterized in that The mass ratio of the nucleating agent to EVOH is 1:50 to 1:100; The ethylene content in the EVOH is 10-90 wt %.

10. The preparation method according to claim 8 or 9, characterized in that: The mixing time is 5 to 100 min; The drying temperature is 60-110°C and the drying time is 1-24 hours; The extrusion temperature is 150-250°C.

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