A method for preparing a polyester resin coating for improving adhesion of a thin film

Abstract

The application relates to a preparation method of a polyester resin coating for improving film adhesion, and belongs to the technical field of high polymer materials. The polyester resin has certain strength and better adhesion by taking terephthalic acid and dihydric alcohol as hard segments of the polyester resin, taking polyethylene glycol and adipic acid as soft segments, and by proportioning to obtain a good balance between hardness and flexibility; the hard segments of the polyester resin are introduced with strong polar groups of sulfonic acid groups, the adhesion between the polyester resin coating and a film base material is improved; and the adhesion of the coating is further improved by adding fillers to increase surface roughness.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer materials, and relates to a preparation method of polyester resin coating for improving the adhesion of a film. BACKGROUND

[0002] Polyester resin is an important class of synthetic polymer materials, widely used in coatings, fibers, plastics, and composite materials. Its basic structure is composed of ester bonds formed by the condensation reaction of diacids and polyols, with good mechanical properties, chemical resistance, and thermal stability. Polyester resins can be divided into saturated and unsaturated polyester resins according to their applications and performance requirements. Saturated polyester resins are usually used in coatings and thermoplastic applications, while unsaturated polyester resins are widely used in glass fiber reinforced plastics and casting resins. The molecular structure of polyester resins can be optimized by adjusting the ratio of hard and soft segments, introducing different types of polyols and acids, and adding cross-linking agents and fillers to meet specific application requirements.

[0003] Thin film materials play a key role in packaging, electronics, construction, and automotive industries. To ensure the functionality and durability of the film in these applications, the adhesion of the film surface to other materials is crucial, especially for low surface energy films made of materials such as PE, PP, and PET, which require improved surface adhesion. Polyester resin coatings, due to their excellent mechanical properties and chemical stability, are an ideal choice for improving film adhesion. First, the molecular structure of polyester resins can be chemically modified and physically modified to enhance the interfacial bonding between the film and the resin. Second, the thermoplastic characteristics of polyester resins allow them to form a good physical anchor with the substrate surface during processing. In addition, polyester resins can form a three-dimensional network structure through cross-linking reactions, further improving the chemical bonding between the film and the resin. By reasonably designing the molecular structure and processing technology of polyester resins, the adhesion of the film can be significantly improved, thereby enhancing its performance in harsh environments.

[0004] Despite the significant advantages of polyester resin coatings in improving film adhesion, there are still some deficiencies in existing technology. Traditional polyester resin coating formulations may improve adhesion while reducing the flexibility and impact resistance of the material, affecting the overall performance of the film. SUMMARY

[0005] The application relates to a preparation method of polyester resin coating for improving film adhesion, and belongs to the technical field of high polymer materials. The polyester resin coating for improving film adhesion has the advantages that the polyester resin coating has certain strength and better adhesion; the strong polar group sulfonic acid group is introduced into the hard segment of the polyester resin, so that the adhesion between the polyester film and the base material is improved; and the surface roughness is increased by adding the filler, so that the adhesion is further improved.

[0006] The object of the application can be achieved by the following technical scheme.

[0007] A preparation method of polyester resin coating for improving film adhesion comprises the following steps.

[0008] (1) hard segment monomers and soft segment monomers are respectively added into a reaction kettle, an esterification catalyst is added, and heating is carried out at 180-220 DEG C for 3-8 hours to form hard segment prepolymers and soft segment prepolymers respectively;

[0009] (2) the hard segment prepolymers and the soft segment prepolymers are added into a polycondensation catalyst, are uniformly mixed in a vacuum, and are heated to 230-280 DEG C to carry out polycondensation for 4-10 hours to form polyester resin;

[0010] (3) cooling is carried out to 120-150 DEG C, fillers and solvents are added, ultrasonic treatment and stirring are carried out for 30-60 minutes to uniformly mix and form polyester resin coating;

[0011] As a preferred technical scheme of the application, the mass ratio of the hard segment monomers, the soft segment monomers, the esterification catalyst, the polycondensation catalyst and the fillers is 20-40:45-65:0.1-1:0.1-1:4-8.

[0012] As a preferred technical scheme of the application, the hard segment monomers in step (1) are terephthalic acid, sulfonated terephthalic acid and dihydric alcohol; the sulfonated terephthalic acid is 5-sulfonated sodium terephthalate, the dihydric alcohol is one of ethylene glycol, 1,4-butanediol and neopentyl glycol; and the mass ratio of the terephthalic acid, the sulfonated terephthalic acid and the dihydric alcohol is 1:0.2-0.4:0.6-0.9.

[0013] As a preferred technical scheme of the application, the soft segment monomers in step (1) are polyethylene glycol and adipic acid; and the mass ratio of the polyethylene glycol and the adipic acid is 1:0.08-0.15.

[0014] As a preferred technical scheme of the application, the esterification catalyst in step (1) is one of 98% concentrated sulfuric acid, p-toluenesulfonic acid and phosphoric acid.

[0015] As a preferred technical solution of the present application, water produced in the esterification reaction in step (1) is continuously removed by vacuum distillation or using a water trap to promote the esterification reaction to proceed.

[0016] As a preferred technical solution of the present application, the polycondensation catalyst in step (2) is one of Sb2O3, Sb(Ac)3, ethylene glycol antimony, and GeO2; and the vacuum pressure is 100-1000 Pa.

[0017] As a preferred technical solution of the present application, the filler in step (3) is nano-silicon dioxide or nano-zinc oxide; and the solvent is one or several of toluene, acetone butanone, and butyl acetate.

[0018] The present application has the following beneficial effects:

[0019] (1) The present application uses terephthalic acid and polyol as the hard segment of the polyester resin, and polyethylene glycol and adipic acid as the soft segment. The terephthalic acid has a rigid benzene ring structure, which can provide high mechanical strength and thermal stability; the polyethylene glycol has a flexible chain segment, which can provide good flexibility and impact strength. Through reasonable design and optimization, the polyester resin can achieve a good balance between hardness and flexibility, so that the polyester resin coating has both certain strength and better adhesion.

[0020] (2) The present application introduces sulfonic acid groups into the hard segment of the polyester resin. The sulfonic acid group is a strong polar group with high electron affinity, which can form a firm bond with the polar functional groups on the surface of the polar film substrate (such as PET, PVC, PI film material) through hydrogen bonding or dipole-dipole interaction; and the hydrophilicity and surface wettability of the polyester resin coating are improved, and the coating with good wettability can spread more easily on the surface of the film substrate, thereby increasing the interface contact area and helping to form stronger adhesion; the sulfonic acid group may be ionized in a solution or humid environment (such as Na + and -COO - in -COONa), and its negative charge can produce electrostatic attraction with the positively charged surface of the substrate, thereby improving the adhesion between the polyester resin coating and the film substrate on the surface of some non-polar film substrates (such as PE, PP film material).

[0021] (3) The present application adds fillers such as nano-silicon dioxide or nano-zinc oxide, which can increase the surface roughness and provide more physical anchoring points, thereby further improving the adhesion and improving the mechanical properties and thermal stability of the material. DETAILED DESCRIPTION

[0022] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purposes, the specific embodiments, structures, features and effects according to the present application are described in detail as follows in combination with examples.

[0023] In the following examples and comparative examples, the polyethylene glycol is purchased from Haian Petrochemical Factory in Jiangsu Province, model PEG-1500; the silicon dioxide is purchased from Naiou Nanometer Technology Co., Ltd., particle size 50 nm; the zinc oxide is purchased from Baoheng Chemical Technology Co., Ltd.

[0024] Example 1

[0025] A preparation method of a polyester resin coating for improving film adhesion, comprising the following steps:

[0026] (1) hard segment monomers and soft segment monomers are respectively added to a reaction kettle, an esterification catalyst is added and heated to 200°C for esterification reaction for 5 hours, to form hard segment prepolymers and soft segment prepolymers respectively;

[0027] (2) the hard segment prepolymers and the soft segment prepolymers are added to a polycondensation catalyst, mixed uniformly in vacuum and heated to 250°C for polycondensation for 6 hours, to form polyester resin;

[0028] (3) cooled to 135°C, fillers and solvents are added, ultrasonic treatment and stirring for 45 minutes to mix uniformly to form polyester resin coating;

[0029] The mass ratio of the hard segment monomers, the soft segment monomers, the esterification catalyst, the polycondensation catalyst and the fillers is 30:55:0.5:0.5:6.

[0030] In step (1), the hard segment monomers are terephthalic acid, sulfonated terephthalic acid and dihydric alcohol; the sulfonated terephthalic acid is sodium 5-sulfoisophthalate, and the dihydric alcohol is one of ethylene glycol, 1,4-butanediol and neopentyl glycol; the mass ratio of the terephthalic acid, the sulfonated terephthalic acid and the dihydric alcohol is 1:0.3:0.8.

[0031] In step (1), the soft segment monomers are polyethylene glycol and adipic acid; the mass ratio of the polyethylene glycol and the adipic acid is 1:0.1.

[0032] In step (1), the esterification catalyst is 98% concentrated sulfuric acid.

[0033] In the esterification reaction process of step (1), water produced in the reaction is continuously removed by reduced pressure distillation or using a water trap, to promote the esterification reaction to proceed.

[0034] In step (2), the polycondensation catalyst is Sb2O3; the vacuum pressure is 500 Pa.

[0035] In step (3), the fillers are nano silicon dioxide; the solvents are butanone.

[0036] Example 2

[0037] A preparation method of a polyester resin coating for improving film adhesion, comprising the following steps:

[0038] (1) hard segment monomers and soft segment monomers are respectively added to a reaction kettle, an esterification catalyst is added, and heating is performed to 180 DEG C for esterification reaction for 8 hours to form hard segment prepolymers and soft segment prepolymers respectively;

[0039] (2) the hard segment prepolymers and the soft segment prepolymers are added to a polycondensation catalyst, mixed uniformly in vacuum, and heated to 230 DEG C for polycondensation for 4 hours to form polyester resin;

[0040] (3) cooling to 120 DEG C, adding fillers and solvents, ultrasonic treatment and stirring for 30 minutes to mix uniformly to form polyester resin coating;

[0041] The mass ratio of the hard segment monomers, the soft segment monomers, the esterification catalyst, the polycondensation catalyst and the fillers is 20:45:0.1:0.1:4.

[0042] In step (1), the hard segment monomers are terephthalic acid, sulfonated terephthalic acid and dihydric alcohol; the sulfonated terephthalic acid is sodium 5-sulfoisophthalate, and the dihydric alcohol is 1,4-butanediol; the mass ratio of the terephthalic acid, the sulfonated terephthalic acid and the dihydric alcohol is 1:0.2:0.6.

[0043] In step (1), the soft segment monomers are polyethylene glycol and adipic acid; the mass ratio of the polyethylene glycol and the adipic acid is 1:0.08.

[0044] In step (1), the esterification catalyst is p-toluenesulfonic acid.

[0045] In the esterification reaction process of step (1), water produced in the reaction is continuously removed by reduced pressure distillation or using a water trap to promote the esterification reaction to proceed.

[0046] In step (2), the polycondensation catalyst is Sb(Ac)3; the vacuum pressure is 100 Pa.

[0047] In step (3), the fillers are nanosilica; and the solvents are toluene.

[0048] Example 3

[0049] A preparation method of a polyester resin coating for improving film adhesion, comprising the following steps:

[0050] (1) hard segment monomers and soft segment monomers are respectively added to a reaction kettle, an esterification catalyst is added, and heating is performed to 220 DEG C for esterification reaction for 8 hours to form hard segment prepolymers and soft segment prepolymers respectively;

[0051] (2) the hard segment prepolymer and the soft segment prepolymer are added to a polycondensation catalyst, mixed uniformly in vacuum and heated to 280℃ for polycondensation for 4 hours to form a polyester resin;

[0052] (3) the temperature is lowered to 150℃, the filler and the solvent are added, ultrasonic treatment and stirring are performed for 60 minutes to mix uniformly to form a polyester resin coating;

[0053] As a preferred technical solution of the present application, the mass ratio of the hard segment monomer, the soft segment monomer, the esterification catalyst, the polycondensation catalyst and the filler is 40:65:1:1:8.

[0054] The hard segment monomer in step (1) is terephthalic acid, sulfonated terephthalic acid and dihydric alcohol; the sulfonated terephthalic acid is sodium 5-sulfonated terephthalate, and the dihydric alcohol is neopentyl glycol; the mass ratio of the terephthalic acid, the sulfonated terephthalic acid and the dihydric alcohol is 1:0.4:0.9.

[0055] The soft segment monomer in step (1) is polyethylene glycol and adipic acid; the mass ratio of the polyethylene glycol and the adipic acid is 1:0.15.

[0056] The esterification catalyst in step (1) is phosphoric acid.

[0057] In the esterification reaction process in step (1), water produced in the reaction is continuously removed by reduced pressure distillation or using a water trap to promote the esterification reaction to proceed.

[0058] The polycondensation catalyst in step (2) is ethylene glycol antimony; the vacuum pressure is 1000 Pa.

[0059] The filler in step (3) is nano zinc oxide; the solvent is acetone.

[0060] Example 4

[0061] A preparation method of a polyester resin coating for improving the adhesion of a thin film, comprising the following steps:

[0062] (1) the hard segment monomer and the soft segment monomer are respectively added to a reaction kettle, an esterification catalyst is added and heated to 190℃ for esterification reaction for 7 hours to respectively form a hard segment prepolymer and a soft segment prepolymer;

[0063] (2) the hard segment prepolymer and the soft segment prepolymer are added to a polycondensation catalyst, mixed uniformly in vacuum and heated to 240℃ for polycondensation for 9 hours to form a polyester resin;

[0064] (3) the temperature is lowered to 130℃, the filler and the solvent are added, ultrasonic treatment and stirring are performed for 50 minutes to mix uniformly to form a polyester resin coating.

[0065] The mass ratio of the hard segment monomer, the soft segment monomer, the esterification catalyst, the polycondensation catalyst, and the filler is 30:50:0.2:0.2:5.

[0066] The hard segment monomer in step (1) is terephthalic acid, sulfonated terephthalic acid, and dihydric alcohol; the sulfonated terephthalic acid is sodium 5-sulfoisophthalate, and the dihydric alcohol is ethylene glycol; the mass ratio of the terephthalic acid, the sulfonated terephthalic acid, and the dihydric alcohol is 1:0.3:0.7.

[0067] The soft segment monomer in step (1) is polyethylene glycol and adipic acid; the mass ratio of the polyethylene glycol and the adipic acid is 1:0.09.

[0068] The esterification catalyst in step (1) is 98% concentrated sulfuric acid.

[0069] In the esterification reaction process in step (1), water produced in the reaction is continuously removed by reduced pressure distillation or using a water trap to promote the esterification reaction to proceed.

[0070] The polycondensation catalyst in step (2) is GeO2; the vacuum pressure is 200 Pa.

[0071] The filler in step (3) is nano zinc oxide; the solvent is a mixed solvent of toluene and butanone.

[0072] Example 5

[0073] A preparation method of a polyester resin coating for improving the adhesion of a thin film, comprising the following steps:

[0074] (1) hard segment monomers and soft segment monomers are respectively added to a reaction kettle, an esterification catalyst is added, and heating is performed to 210°C to perform esterification reaction for 4 hours to respectively form hard segment prepolymers and soft segment prepolymers;

[0075] (2) the hard segment prepolymers and the soft segment prepolymers are added to a polycondensation catalyst, mixed uniformly in a vacuum, and heated to 270°C to perform polycondensation for 5 hours to form a polyester resin;

[0076] (3) cooling is performed to 140°C, a filler and a solvent are added, ultrasonic treatment and stirring are performed for 40 minutes to mix uniformly to form a polyester resin coating.

[0077] The mass ratio of the hard segment monomer, the soft segment monomer, the esterification catalyst, the polycondensation catalyst, and the filler is 35:60:0.8:0.8:7.

[0078] The hard segment monomer in step (1) is terephthalic acid, sulfonated terephthalic acid, and dihydric alcohol; the sulfonated terephthalic acid is sodium 5-sulfoisophthalate, and the dihydric alcohol is 1,4-butanediol; the mass ratio of the terephthalic acid, the sulfonated terephthalic acid, and the dihydric alcohol is 1:0.4:0.8.

[0079] The soft segment monomer in step (1) is polyethylene glycol and adipic acid; the mass ratio of the polyethylene glycol and adipic acid is 1:0.14.

[0080] The esterification catalyst in step (1) is p-toluenesulfonic acid.

[0081] In the esterification reaction in step (1), water produced in the reaction is continuously removed by vacuum distillation or using a water trap to promote the esterification reaction to proceed.

[0082] The polycondensation catalyst in step (2) is Sb2O3; the vacuum pressure is 800 Pa.

[0083] The filler in step (3) is nano-silicon dioxide; the solvent is butyl acetate.

[0084] Comparative Example 1

[0085] On the basis of Example 1, the hard segment monomer is changed to terephthalic acid and ethylene glycol, the mass ratio of terephthalic acid and ethylene glycol is 1.3:0.8, and the rest is consistent with Example 1.

[0086] Comparative Example 2

[0087] On the basis of Example 1, no filler is added, and the rest is consistent with Example 1.

[0088] Performance test:

[0089] The polyester resin coatings obtained in Examples 1-5 and Comparative Examples 1-2 are respectively coated on 50 μm PET film, and attention is paid to keep the dry coating amount of the coating layer at 1-2 μm during coating, and then dried, and then the adhesion is tested according to the standard GB / T 9286-2021, and the smaller the grade, the better the adhesion.

[0090]

[0091]

[0092] It can be known from the test results that the introduction of sulfonated terephthalic acid and the addition of filler can improve the adhesion of the polyester resin coating.

[0093] The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, as long as the changes or modifications do not deviate from the technical solution of the present application. Any indirect modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present application still belong to the scope of the technical solution of the present application.

Claims

1. A method for preparing a polyester resin coating for improving adhesion of a thin film, characterized by: The method comprises the following steps: (1) adding hard segment monomers and soft segment monomers into a reaction kettle respectively, adding esterification catalysts and heating to 180-220 DEG C for esterification reaction for 3-8 hours to form hard segment prepolymers and soft segment prepolymers respectively; (2) adding the hard segment prepolymers and the soft segment prepolymers into polycondensation catalysts, mixing uniformly in vacuum and heating to 230-280 DEG C for polycondensation for 4-10 hours to form polyester resins; (3) cooling to 120-150 DEG C, adding fillers and solvents, ultrasonic treatment and stirring for 30-60 minutes to mix uniformly to form polyester resin coatings; The mass ratio of the hard segment monomers, the soft segment monomers, the esterification catalysts, the polycondensation catalysts and the fillers is 20-40:45-65:0.1-1:0.1-1:4-8; In step (1), the hard segment monomers are terephthalic acid, sulfonated terephthalic acid and dihydric alcohol; the sulfonated terephthalic acid is sodium 5-sulfoisophthalate, and the dihydric alcohol is one of ethylene glycol, 1,4-butanediol and neopentyl glycol; the mass ratio of the terephthalic acid, the sulfonated terephthalic acid and the dihydric alcohol is 1:0.2-0.4:0.6-0.9; In step (1), the soft segment monomers are polyethylene glycol and adipic acid; the mass ratio of the polyethylene glycol and the adipic acid is 1:0.08-0.15; In step (3), the fillers are nano-silicon dioxide or nano-zinc oxide.

2. The method for preparing a polyester resin coating for improving film adhesion according to claim 1, characterized in that: In step (1), the esterification catalysts are one of 98% concentrated sulfuric acid, p-toluenesulfonic acid and phosphoric acid.

3. The method for preparing a polyester resin coating for improving film adhesion according to claim 1, characterized in that: In step (1), water produced in the esterification reaction is continuously removed by reduced pressure distillation or using a water trap to promote the esterification reaction.

4. The method for preparing a polyester resin coating for improving film adhesion according to claim 1, characterized in that: In step (2), the polycondensation catalysts are one of Sb2O3, Sb(Ac)3, ethylene glycol antimony and GeO2; the vacuum pressure is 100-1000 Pa.

5. The method for preparing a polyester resin coating for improving film adhesion according to claim 1, characterized in that: In step (3), the solvents are one or more of toluene, acetone, butanone and butyl acetate.

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