High-strength blister box sheet and preparation method thereof

Abstract

The invention discloses a high-strength plastic uptake box sheet and a preparation method thereof, and belongs to the technical field of high polymer material preparation, the high-strength plastic uptake box sheet comprises modified polyester resin, and the modified polyester resin is prepared by taking trimesic acid as a raw material and mixing the trimesic acid with the modified polyester resin. The method comprises the following steps: reacting excessive trimesic acid with tert-butylamine under the action of a condensing agent to obtain monocarboxyl tert-butylamidated benzenetricarboxylic acid, reacting the monocarboxyl tert-butylamidated benzenetricarboxylic acid with 9, 10-di (hydroxymethyl) anthracene under the action of the condensing agent to form ester, hydrolyzing a tert-butylamido bond with hydroxylamine to obtain dicarboxylic acid with a macrocyclic tetralactone structure, and reacting the dicarboxylic acid with terephthalic acid, ethylene glycol and 3, 3 '-dihydroxybenzenetricarboxylic acid to obtain the high-purity trimesic acid. According to the invention, 1, 4-dihydroxyl-3-cyclobutene-1, 2-diketone is used as a polymerization monomer and is subjected to copolymerization so as to obtain the product; according to the polyester-based high-strength blister box sheet, the toughness can be improved on the premise that other properties are not obviously sacrificed, and the requirements of the packaging protection field for the strength and toughness properties of polyester materials are met.

Description

Technical Field

[0001] The invention relates to the technical field of polymer material preparation, in particular to a high-strength blister box sheet and a preparation method thereof. Background Art

[0002] Blister sheet is a material used in plastic processing. The main process involves heating and softening a flat sheet, vacuum-adhering it to a mold surface, and then cooling it to form the final product. It is widely used in industries such as plastic packaging, lighting, advertising, and decoration. With the rapid development of the food, pharmaceutical, and electronics industries, the performance shortcomings of traditional blister packaging in terms of load-bearing capacity, impact resistance, and protective properties have become increasingly apparent. High-strength modification of blister sheet is an inevitable requirement for technological upgrades in the current packaging industry.

[0003] Commonly used blister sheets include PVC, PET, PP and PS. Among them, PET sheets have been widely used due to their hardness, high brightness, non-toxicity, and recyclability. However, their inherent brittle defects (such as low impact strength and insufficient elongation at break) seriously restrict their application under dynamic load impact. Unmodified polyester plastics are prone to brittle fracture when subjected to external force, resulting in failure of protective packaging. Therefore, toughening modification has become an important technical means to improve the comprehensive performance of polyester plastics and expand their application range.

[0004] Existing toughening modification methods mainly include elastomer blending, such as POE, EPDM, etc.; particle filling, such as montmorillonite, silica, etc.; and chemical modification, such as the introduction of flexible segments through copolymerization; among them, elastomer blending introduces flexible phases or energy dissipation structures to improve its notched impact strength, which is low in cost but has poor compatibility. Particle filling can inhibit crack propagation and has high requirements for dispersibility, and also has the problem of poor compatibility; chemical modification generally introduces flexible segments through copolymerization, and the modification process is more complicated; and the above-mentioned toughening modification methods do not balance the properties of strength and toughness. The toughening is at the expense of strength, and it is difficult to maintain its mechanical strength while improving toughness. Summary of the Invention

[0005] In view of the above problems, the present invention provides a high-strength blister box sheet and a preparation method thereof.

[0006] The purpose of the present invention is achieved by adopting the following technical solutions:

[0007] A high-strength blister box sheet comprises a modified polyester resin, and a method for preparing the modified polyester resin comprises the following steps:

[0008] (1) Weigh trimesic acid and dissolve it in tetrahydrofuran solvent, add N,N-diisopropylethylamine, stir thoroughly, heat to 30-40°C, add tert-butylamine in small amounts and multiple times under stirring, continue stirring and react for 0.5-2 hours after the addition is complete, concentrate under reduced pressure, purify on a silica gel column to remove unreacted reactants, and evaporate the solvent under reduced pressure to obtain a precursor product;

[0009] (2) Weigh 9,10-di(hydroxymethyl)anthracene and dissolve it in dichloromethane solvent, add dicyclohexylcarbodiimide, and stir and mix thoroughly to obtain solution A; dissolve the precursor product in dichloromethane solvent, add 4-dimethylaminopyridine and stir and mix thoroughly to obtain solution B; add the solution B to the solution A in small amounts and multiple times under stirring, continue stirring and reacting for 1-3 hours after the addition is completed, and evaporate the solvent under reduced pressure to obtain an intermediate product;

[0010] (3) dissolving the intermediate product in tetrahydrofuran solvent, adding ethanol aqueous solution of hydroxylamine hydrochloride, adjusting the pH to 4-5 with alkaline solution, stirring and reacting at 50-60° C. for 3-6 hours, cooling and adding to cold methanol solvent, separating the precipitate, washing and drying to obtain the modified monomer;

[0011] (4) Weighing terephthalic acid, ethylene glycol, the modified monomer and 3,4-dihydroxy-3-cyclobutene-1,2-dione respectively and mixing them, heating them under a protective atmosphere, the reaction pressure is 3-3.5 bar, and stirring them at 220-260° C. for 2-3 hours, adding tetrabutyl titanate and triphenyl phosphate, heating them to 270-280° C. under a pressure condition of not more than 100 Pa, and stirring them at this temperature for 2-3 hours to obtain a polymer product.

[0012] In some preferred embodiments, the high-strength blister box sheet material comprises polyester resin, which is a polymerization product of a dibasic acid and a diol, and the mass ratio of the polyester resin in the high-strength blister box sheet material is 5-35%.

[0013] In some preferred embodiments, the polyester resin is one or more of polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate-1,4-cyclohexanedimethanol ester, and polyethylene terephthalate-neopentyl alcohol ester.

[0014] In some preferred embodiments, the high-strength blister box sheet material includes an auxiliary agent, and the mass ratio of the auxiliary agent in the high-strength blister box sheet material is 0.1-2%.

[0015] In some preferred embodiments, the auxiliary agent is one or more of an antioxidant, a lubricant, a plasticizer, a filler, and a dispersant.

[0016] In some preferred embodiments, the mass ratio of the trimesic acid to the N,N-diisopropylethylamine and the tert-butylamine in step (1) is 10:(6.5-7.7):(3-4).

[0017] In some preferred embodiments, the mass ratio of the 9,10-di(hydroxymethyl)anthracene to the dicyclohexylcarbodiimide, the precursor product, and the 4-dimethylaminopyridine in step (2) is 10:(8-9.5):(10.5-12.2):(0.4-0.65).

[0018] In some preferred embodiments, the mass ratio of the intermediate product to the hydroxylamine hydrochloride in step (3) is 10:(5.8-7.2).

[0019] In some preferred embodiments, the mass ratio of the terephthalic acid to the ethylene glycol, the modified monomer and the 3,4-dihydroxy-3-cyclobutene-1,2-dione in step (4) is 10:(4-4.6):(2.2-2.9):(0.78-1).

[0020] Another aspect of the present invention is to provide a method for preparing the high-strength blister box sheet, comprising the following steps:

[0021] The modified polyester resin is uniformly mixed with the polyester resin and the auxiliary agent, and then kneaded. After melt extrusion, the sheet is calendered and cooled. The extrusion temperature is 240-260° C. After the sheet is softened, it is vacuum-formed on a mold and then cooled to obtain the blister box.

[0022] The beneficial effects of the present invention are:

[0023] In view of the problem that the toughening methods in the prior art are generally difficult to maintain their mechanical strength while improving toughness, the present invention provides a polyester-based high-strength blister box sheet, which can improve toughness without significantly sacrificing other properties, and meet the demand for strength and toughness of polyester materials in the field of packaging protection. Specifically, the present invention uses trimesic acid as a raw material, reacts excess trimesic acid with tert-butylamine under the action of a condensing agent to obtain monocarboxylic tert-butylamidized trimesic acid, and then reacts with 9,10-di(hydroxymethyl)anthracene under the action of a condensing agent to form an ester, and after hydrolyzing the tert-butylamide bond with hydroxylamine, obtains a dicarboxylic acid with a macrocyclic tetralactone structure, which is then reacted with terephthalic acid and ethyl ester to form a monocarboxylic tert-butylamidized trimesic acid. The modified polyester resin is prepared by copolymerizing diol and 3,4-dihydroxy-3-cyclobutene-1,2-dione as polymerization monomers. The modified polyester resin has good tensile strength and impact resistance and can be blended with polyester resin for toughening. The present invention simultaneously introduces a macrocyclic tetralactone structure and a squaric acid structure into the PET main chain, utilizes the host-guest recognition effect between the squaric acid and the macrocyclic tetralactone, and forms soft crosslinking points between the PET main chains. On the basis of maintaining the main chain polyester structure, the effect of introducing the modified structure into the main chain on the mechanical strength is reduced through interchain crosslinking. At the same time, the soft crosslinking points based on host-guest recognition provide good energy dissipation sites for the polyester, thereby improving its notched impact strength. DETAILED DESCRIPTION

[0024] The present invention is further described with reference to the following examples.

[0025] Example 1

[0026] A high-strength blister box sheet, composed of polyester resin and modified polyester resin, wherein the mass ratio of the polyester resin to the modified polyester resin is 1:4;

[0027] The polyester resin is polyethylene terephthalate, and the melt index is 26.8 g / 10 min (300° C. / 1.2 kg);

[0028] The preparation method of the modified polyester resin comprises the following steps:

[0029] (1) Weighing trimesic acid and dissolving it in tetrahydrofuran solvent, adding N,N-diisopropylethylamine, stirring and mixing thoroughly, heating to 35°C, adding tert-butylamine in small amounts and multiple times under stirring, continuing to stir and react for 1 hour after the addition is completed, and concentrating under reduced pressure after the reaction is completed. Purifying by silica gel column to remove unreacted reactants, eluting with a mixed solution of ethyl acetate and cyclohexane (v / v=1:1), and distilling off the solvent under reduced pressure to obtain a precursor product; the mass ratio of the trimesic acid to the N,N-diisopropylethylamine and the tert-butylamine is 10:7.1:3.5;

[0030] (2) Weigh 9,10-di(hydroxymethyl)anthracene and dissolve it in dichloromethane solvent, add dicyclohexylcarbodiimide, and stir and mix thoroughly to obtain solution A; dissolve the precursor product in dichloromethane solvent, add 4-dimethylaminopyridine and stir and mix thoroughly to obtain solution B; add the solution B to the solution A in small amounts and multiple times under stirring conditions, continue stirring and reacting for 2 hours after the addition is completed, and evaporate the solvent under reduced pressure to obtain an intermediate product; the mass ratio of the 9,10-di(hydroxymethyl)anthracene to the dicyclohexylcarbodiimide, the precursor product, and the 4-dimethylaminopyridine is 10:8.6:11.2:0.5;

[0031] (3) dissolving the intermediate product in tetrahydrofuran solvent, adding ethanol aqueous solution of hydroxylamine hydrochloride, adjusting the pH to 4-5 with alkaline solution, stirring and reacting at 50° C. for 4 hours, cooling and adding to cold methanol solvent, separating the precipitate, washing and drying to obtain the modified monomer; the mass ratio of the intermediate product to the hydroxylamine hydrochloride is 10:6.3;

[0032] (4) Weighing terephthalic acid, ethylene glycol, the modified monomer and 3,4-dihydroxy-3-cyclobutene-1,2-dione respectively and mixing them, heating them under a protective atmosphere, the reaction pressure is 3-3.5 bar, stirring and reacting at 235° C. for 2 hours, adding tetrabutyl titanate and triphenyl phosphate, heating them to 270-280° C. under a pressure condition of not more than 100 Pa, stirring and reacting for 2 hours to obtain a polymer product; the mass ratio of the terephthalic acid to the ethylene glycol, the modified monomer and the 3,4-dihydroxy-3-cyclobutene-1,2-dione is 10:4.3:2.6:0.87;

[0033] The preparation method of the high-strength blister box sheet comprises the following steps:

[0034] The modified polyester resin is uniformly mixed with the polyester resin and the auxiliary agent, and then kneaded. After melt extrusion, the sheet is calendered and cooled. The extrusion temperature is 240-260° C. After the sheet is softened, it is vacuum-formed on a mold and then cooled to obtain the blister box.

[0035] Example 2

[0036] A high-strength blister box sheet, composed of polyester resin and modified polyester resin, wherein the mass ratio of the polyester resin to the modified polyester resin is 1:8;

[0037] The polyester resin is polyethylene terephthalate, and the melt index is 26.8 g / 10 min (300° C. / 1.2 kg);

[0038] The preparation method of the modified polyester resin comprises the following steps:

[0039] (1) Weighing trimesic acid and dissolving it in tetrahydrofuran solvent, adding N,N-diisopropylethylamine, stirring and mixing thoroughly, heating to 35°C, adding tert-butylamine in small amounts and multiple times under stirring, continuing to stir and react for 1 hour after the addition is completed, and concentrating under reduced pressure after the reaction is completed. Purifying by silica gel column to remove unreacted reactants, eluting with a mixed solution of ethyl acetate and cyclohexane (v / v=1:1), and distilling off the solvent under reduced pressure to obtain a precursor product; the mass ratio of the trimesic acid to the N,N-diisopropylethylamine and the tert-butylamine is 10:6.7:3;

[0040] (2) Weigh 9,10-di(hydroxymethyl)anthracene and dissolve it in dichloromethane solvent, add dicyclohexylcarbodiimide, and stir and mix thoroughly to obtain solution A; dissolve the precursor product in dichloromethane solvent, add 4-dimethylaminopyridine and stir and mix thoroughly to obtain solution B; add the solution B to the solution A in small amounts and multiple times under stirring conditions, continue stirring and reacting for 2 hours after the addition is completed, and evaporate the solvent under reduced pressure to obtain an intermediate product; the mass ratio of the 9,10-di(hydroxymethyl)anthracene to the dicyclohexylcarbodiimide, the precursor product, and the 4-dimethylaminopyridine is 10:9:10.8:0.6;

[0041] (3) dissolving the intermediate product in tetrahydrofuran solvent, adding ethanol aqueous solution of hydroxylamine hydrochloride, adjusting the pH to 4-5 with alkaline solution, stirring and reacting at 50° C. for 4 hours, cooling and adding to cold methanol solvent, separating the precipitate, washing and drying to obtain the modified monomer; the mass ratio of the intermediate product to the hydroxylamine hydrochloride is 10:6;

[0042] (4) Weighing terephthalic acid, ethylene glycol, the modified monomer and 3,4-dihydroxy-3-cyclobutene-1,2-dione respectively and mixing them, heating them under a protective atmosphere, the reaction pressure is 3-3.5 bar, stirring and reacting at 235° C. for 2 hours, adding tetrabutyl titanate and triphenyl phosphate, heating them to 270-280° C. under a pressure condition of not more than 100 Pa, stirring and reacting for 2 hours to obtain a polymer product; the mass ratio of the terephthalic acid to the ethylene glycol, the modified monomer and the 3,4-dihydroxy-3-cyclobutene-1,2-dione is 10:4.5:2.9:0.78;

[0043] The preparation method of the high-strength blister box sheet is the same as that of Example 1.

[0044] Example 3

[0045] A high-strength blister box sheet, composed of polyester resin and modified polyester resin, wherein the mass ratio of the polyester resin to the modified polyester resin is 1:4;

[0046] The polyester resin is polyethylene terephthalate, and the melt index is 26.8 g / 10 min (300° C. / 1.2 kg);

[0047] The preparation method of the modified polyester resin comprises the following steps:

[0048] (1) Weighing terephthalic acid, ethylene glycol and 3,4-dihydroxy-3-cyclobutene-1,2-dione respectively and mixing them, heating them under a protective atmosphere, the reaction pressure is 3-3.5 bar, stirring and reacting at 235° C. for 2 hours, adding tetrabutyl titanate and triphenyl phosphate, heating them to 270-280° C. under a pressure condition not greater than 100 Pa, stirring and reacting for 2 hours to obtain a polymer product; the mass ratio of the terephthalic acid to the ethylene glycol to the 3,4-dihydroxy-3-cyclobutene-1,2-dione is 10:4.3:0.87;

[0049] The preparation method of the high-strength blister box sheet is the same as that of Example 1.

[0050] Example 4

[0051] A high-strength blister box sheet, composed of polyester resin and modified polyester resin, wherein the mass ratio of the polyester resin to the modified polyester resin is 1:4;

[0052] The polyester resin is polyethylene terephthalate, and the melt index is 26.8 g / 10 min (300° C. / 1.2 kg);

[0053] The preparation method of the modified polyester resin comprises the following steps:

[0054] (1) Weighing trimesic acid and dissolving it in tetrahydrofuran solvent, adding N,N-diisopropylethylamine, stirring and mixing thoroughly, heating to 35°C, adding tert-butylamine in small amounts and multiple times under stirring, continuing to stir and react for 1 hour after the addition is completed, and concentrating under reduced pressure after the reaction is completed. Purifying by silica gel column to remove unreacted reactants, eluting with a mixed solution of ethyl acetate and cyclohexane (v / v=1:1), and distilling off the solvent under reduced pressure to obtain a precursor product; the mass ratio of the trimesic acid to the N,N-diisopropylethylamine and the tert-butylamine is 10:7.1:3.5;

[0055] (2) Weigh 9,10-di(hydroxymethyl)anthracene and dissolve it in dichloromethane solvent, add dicyclohexylcarbodiimide, and stir and mix thoroughly to obtain solution A; dissolve the precursor product in dichloromethane solvent, add 4-dimethylaminopyridine and stir and mix thoroughly to obtain solution B; add the solution B to the solution A in small amounts and multiple times under stirring conditions, continue stirring and reacting for 2 hours after the addition is completed, and evaporate the solvent under reduced pressure to obtain an intermediate product; the mass ratio of the 9,10-di(hydroxymethyl)anthracene to the dicyclohexylcarbodiimide, the precursor product, and the 4-dimethylaminopyridine is 10:8.6:11.2:0.5;

[0056] (3) dissolving the intermediate product in tetrahydrofuran solvent, adding ethanol aqueous solution of hydroxylamine hydrochloride, adjusting the pH to 4-5 with alkaline solution, stirring and reacting at 50° C. for 4 hours, cooling and adding to cold methanol solvent, separating the precipitate, washing and drying to obtain the modified monomer; the mass ratio of the intermediate product to the hydroxylamine hydrochloride is 10:6.3;

[0057] (4) Weighing terephthalic acid, ethylene glycol and the modified monomer separately and mixing them, heating under a protective atmosphere, the reaction pressure is 3-3.5 bar, stirring and reacting at 235° C. for 2 hours, adding tetrabutyl titanate and triphenyl phosphate, heating to 270-280° C. under a pressure condition of not more than 100 Pa, stirring and reacting for 2 hours to obtain a polymer product; the mass ratio of the terephthalic acid to the ethylene glycol to the modified monomer is 10:4.3:2.6:0.87;

[0058] The preparation method of the high-strength blister box sheet is the same as that of Example 1.

[0059] Example 5

[0060] A high-strength blister box sheet is composed of polyester resin, modified polyester resin and antioxidant 1010, wherein the mass ratio of the polyester resin to the modified polyester resin and the antioxidant 1010 is 1:4:0.01;

[0061] The polyester resin is polyethylene terephthalate, and the melt index is 26.8 g / 10 min (300° C. / 1.2 kg);

[0062] The preparation method of the modified polyester resin is the same as that of Example 1;

[0063] The preparation method of the high-strength blister box sheet comprises the following steps:

[0064] The modified polyester resin is mixed evenly with the polyester resin and the antioxidant 1010, and then kneaded. After melt extrusion, the sheet is calendered and cooled. The extrusion temperature is 240-260° C. After the sheet is softened, it is vacuum-formed on a mold and then cooled to obtain the blister box.

[0065] The mechanical properties of the high-strength blister box plastics prepared in Examples 1-5 were measured compared with unmodified polyethylene terephthalate resin (melt index 26.8 g / 10 min (300 ° C. / 1.2 kg)), wherein the tensile strength was measured according to the reference standard ISO 527-1-2019; the flexural strength and flexural modulus were measured according to the reference standard ISO 178-2019; the notched impact strength was measured according to the reference standard ISO 179-1-2023; and the reference standard ISO 1133-1-2022. The test results are shown in the following table:

[0066]

[0067]

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A high-strength blister box sheet, characterized in that: The invention relates to a modified polyester resin, wherein the preparation method of the modified polyester resin comprises the following steps: (1) Weigh trimesic acid and dissolve it in tetrahydrofuran solvent, add N,N-diisopropylethylamine, stir thoroughly, heat to 30-40°C, add tert-butylamine in small amounts and multiple times under stirring, continue stirring and react for 0.5-2 hours after the addition is complete, concentrate under reduced pressure, purify, and evaporate the solvent under reduced pressure to obtain a precursor product; (2) Weigh 9,10-di(hydroxymethyl)anthracene and dissolve it in dichloromethane solvent, add dicyclohexylcarbodiimide, and stir and mix thoroughly to obtain solution A; dissolve the precursor product in dichloromethane solvent, add 4-dimethylaminopyridine and stir and mix thoroughly to obtain solution B; add the solution B to the solution A in small amounts and multiple times under stirring, continue stirring and reacting for 1-3 hours after the addition is completed, and evaporate the solvent under reduced pressure to obtain an intermediate product; (3) dissolving the intermediate product in tetrahydrofuran solvent, adding ethanol aqueous solution of hydroxylamine hydrochloride, adjusting the pH to 4-5 with alkaline solution, stirring and reacting at 50-60° C. for 3-6 hours, cooling and adding to cold methanol solvent, separating the precipitate, washing and drying to obtain the modified monomer; (4) Weighing terephthalic acid, ethylene glycol, the modified monomer and 3,4-dihydroxy-3-cyclobutene-1,2-dione respectively and mixing them, heating them under a protective atmosphere, the reaction pressure is 3-3.5 bar, and stirring them at 220-260° C. for 2-3 hours, adding tetrabutyl titanate and triphenyl phosphate, heating them to 270-280° C. under a pressure condition of not more than 100 Pa, and stirring them at this temperature for 2-3 hours to obtain a polymer product.

2. A high-strength blister box sheet according to claim 1, characterized in that: The polyester resin comprises a polymer product of a dibasic acid and a diol, and the mass proportion of the polyester resin in the high-strength blister box sheet is 5-35%.

3. The high-strength blister box sheet according to claim 1, characterized in that: The polyester resin is one or more of polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate-1,4-cyclohexanedimethanol, and polyethylene terephthalate-neopentyl alcohol.

4. The high-strength blister box sheet according to claim 1, characterized in that: The invention comprises an auxiliary agent, wherein the mass proportion of the auxiliary agent in the high-strength blister box sheet is 0.1-2%.

5. The high-strength blister box sheet according to claim 4, characterized in that: The auxiliary agent is one or more of an antioxidant, a lubricant, a plasticizer, a filler, and a dispersant.

6. The high-strength blister box sheet according to claim 1, characterized in that: The mass ratio of the trimesic acid to the N,N-diisopropylethylamine and the tert-butylamine in step (1) is 10:(6.5-7.7):(3-4).

7. The high-strength blister box sheet according to claim 1, characterized in that: The mass ratio of the 9,10-di(hydroxymethyl)anthracene to the dicyclohexylcarbodiimide, the precursor product, and the 4-dimethylaminopyridine in step (2) is 10:(8-9.5):(10.5-12.2):(0.4-0.65).

8. The high-strength blister box sheet according to claim 1, characterized in that: The mass ratio of the intermediate product to the hydroxylamine hydrochloride in step (3) is 10:(5.8-7.2).

9. The high-strength blister box sheet according to claim 1, characterized in that: The mass ratio of the terephthalic acid to the ethylene glycol, the modified monomer and the 3,4-dihydroxy-3-cyclobutene-1,2-dione in step (4) is 10:(4-4.6):(2.2-2.9):(0.78-1).

10. The method for preparing a high-strength blister box sheet according to claim 4 or 5, characterized in that: The following steps are involved: The modified polyester resin is uniformly mixed with the polyester resin and the auxiliary agent, and then kneaded. After melt extrusion, the sheet is calendered and cooled. The extrusion temperature is 240-260° C. After the sheet is softened, it is vacuum-formed on a mold and then cooled to obtain the blister box.

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