High-adhesion and high-hardness modified epoxy coating for PC glass plate and preparation method of high-adhesion and high-hardness modified epoxy coating

Abstract

The invention relates to the technical field of coatings, and discloses a high-adhesion and high-hardness modified epoxy coating for a PC glass plate and a preparation method of the high-adhesion and high-hardness modified epoxy coating. The epoxy coating is prepared from the following raw materials in parts by weight: 20 parts of epoxy resin, 10-20 parts of modified epoxy resin, 15-20 parts of a curing agent, 1-3 parts of modified attapulgite, 2 parts of polycarbonate resin, 0.5-1 part of a dispersing agent, 0.1-0.5 part of a coalescing agent, 0.2-0.4 part of a defoaming agent and the balance of deionized water, the prepared epoxy coating has excellent mechanical properties, has good bonding performance with a PC glass plate, has long-acting antibacterial performance when being applied to the PC glass plate, and can hinder bacterial pollution.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of paint, in particular to a high-bonding and high-hardness modified epoxy coating for PC glass plate and a preparation method thereof. BACKGROUND

[0002] PC glass plate is a polycarbonate plate, which is widely used in the fields of transportation and electronics and electrical appliances due to its high impact resistance, low weight and easy processing. However, the surface hardness of PC glass plate is low and it is easy to be scratched. Epoxy resin coating is mainly prepared from epoxy resin base material and curing agent, and is widely used in various coating fields. It has high hardness, but the surface polarity of PC material is weak. Therefore, the coating layer is easy to fall off when the traditional epoxy coating is directly coated on the surface, so it is necessary to make the epoxy coating have high bonding performance. Attapulgite is a layered chain structure of hydromagnesite-aluminosilicate clay mineral, which is widely used in industrial material field and daily chemical field.

[0003] The high hardness of the epoxy coating for PC glass plate mainly provides surface protection, and the high bonding performance ensures the long-term stability of the coating and the PC glass plate substrate. By combining high hardness and high bonding performance, the PC glass plate can play the advantages of light weight and impact resistance in high requirement fields such as electronics, transportation and building. SUMMARY

[0004] (I) Technical problems to be solved

[0005] In view of the deficiencies of the prior art, the present application provides a high-bonding and high-hardness modified epoxy coating for PC glass plate and a preparation method thereof. The prepared epoxy coating has excellent bonding performance, antibacterial performance and mechanical properties.

[0006] (II) Technical solutions

[0007] A high-bonding and high-hardness modified epoxy coating for PC glass plate is prepared from the following raw materials by weight: 20 parts by weight of epoxy resin, 10-20 parts by weight of modified epoxy resin, 15-20 parts by weight of curing agent, 1-3 parts by weight of modified attapulgite, 2 parts by weight of polycarbonate resin, 0.5-1 parts by weight of dispersing agent, 0.1-0.5 parts by weight of film-forming aid, 0.2-0.4 parts by weight of defoaming agent, and the balance is deionized water, with a total of 100 parts by weight.

[0008] The preparation method of the high-bonding and high-hardness modified epoxy coating for PC glass plate comprises the following steps:

[0009] Step S1, the epoxy resin (E51), quaternary ammonium salt modified bisilane is added to the mass ratio of 4:1 of methylbenzene acetone mixed solution, the temperature is controlled at 90-95℃, deionized water and dibutyltin dilaurate are added, stirring reaction for 6-8h, after the reaction is completed, rotary evaporation, the modified epoxy resin is obtained, in this process, the siloxane contained in the quaternary ammonium salt modified bisilane can graft with the hydroxyl contained in the epoxy resin, the grafting reaction of the more siloxane contained in the quaternary ammonium salt modified bisilane with the epoxy resin can increase the crosslinking density of the modified epoxy resin, the greater the crosslinking density, the higher the crosslinking degree, the higher the coating hardness, the better the mechanical properties, and the flexible organosilicon segment can increase the flexibility of the main chain, further improve the mechanical properties of the substrate;

[0010] Step S2, the modified attapulgite and polycarbonate resin are added to deionized water, stirred and dispersed, then the epoxy resin and modified epoxy resin and dispersing agent are added, stirred for 30min, finally the curing agent, defoaming agent and film forming aid are added, stirred for 20-30min, to obtain the coating;

[0011] It contains a small amount of polycarbonate resin, which has good compatibility with PC glass plate and can be slightly dissolved on the PC surface to achieve the effect of “welding”, promote the adhesion of the coating to the PC glass plate and improve the adhesion performance of the coating to the PC glass plate;

[0012] The modified epoxy resin contains more carboxyl structure, on the one hand, the C=O and O-H of carboxyl can form strong hydrogen bond network with the C=O and O of carbonate bond on PC main chain, improve the adhesion effect of coating, on the other hand, the Ce³⁺ cation on the surface of attapulgite can form coordination bond with carboxyl anion group, thereby improving the adhesion performance of attapulgite and epoxy coating, improving the dispersibility of attapulgite, making it uniformly dispersed in the coating, and further improving the mechanical properties of the coating.

[0013] Preferably, the mass ratio of the epoxy resin (E51), quaternary ammonium salt modified bisilane, deionized water and dibutyltin dilaurate is 100:5-10:0.5-1:0.5-0.6.

[0014] Preferably, the preparation method of the modified epoxy resin comprises the following steps:

[0015] Step S11, under the protection of nitrogen, γ-piperazinyl propyl methyl dimethoxysilane, isolated diene and methanol are added to a flask, stirred and dispersed, the temperature is controlled at 40-50℃, stirring reaction for 5-7h, after the reaction is completed, rotary evaporation, drying, to obtain the target product 1, in this reaction, γ-piperazinyl propyl methyl dimethoxysilane and isolated diene are used as raw materials, through Michael addition reaction, to obtain the target product 1, its reaction formula is:

[0016] wherein n = 2-4;

[0017] Step S12, the target product 1, chloro propionic acid is added to acetone, the mixture is stirred and mixed uniformly, and the temperature is increased to reflux for 8-10 h. After the reaction is completed, filtration is performed, acetone is used for washing, recrystallization is performed, and the quaternary ammonium salt modified disilane is obtained. In the reaction process, the tertiary amine of the target product 1 is subjected to quaternary ammonium reaction with chloro propionic acid to obtain the quaternary ammonium salt modified disilane, and the reaction formula is as follows:

[0018] .

[0019] Preferably, in the step S11, the molar ratio of the γ-piperazinyl propyl methyl dimethoxysilane to the isolated diene is 2-2.2:1.

[0020] Preferably, in the step S11, the isolated diene is one of 1,5-hexadiene, 1,6-heptadiene, and 1,7-octadiene.

[0021] Preferably, in the step S12, the molar ratio of the target product 1 to chloro propionic acid is 1:5-6.

[0022] Preferably, the preparation method of the modified attapulgite clay comprises the following steps:

[0023] The attapulgite clay is dispersed in methanol, the temperature is controlled to be 60-70℃, cerium nitrate hexahydrate and citric acid are added thereto and stirred and mixed for 1-2 h, ammonia water is further added to adjust the pH to 8, and the stirring reaction is continued for 4-6 h. After standing, centrifugation is performed, deionized water is used for washing until neutral, and drying is performed to obtain the modified attapulgite clay. In the reaction process, the attapulgite clay has a large specific surface area, the cerium nitrate hexahydrate provides a cerium source (Ce³⁺), and the citric acid acts as a complexing agent and a dispersant, which can complex the Ce³⁺ to prevent it from prematurely hydrolyzing and precipitating. The Si-OH on the surface of the attapulgite clay is easy to lose H⁺ under alkaline conditions to form a negatively charged Si-O⁻, which is coordinated with the cerium ions to form a covalent coordination bond, thereby firmly fixing the cerium ions on the surface of the attapulgite clay. When the attapulgite clay is added to the paint, the cerium ions therein not only can form a coordination bond with the carboxyl groups, but also can be combined with the active groups in the epoxy resin, thereby improving the compatibility of the attapulgite clay with the epoxy resin matrix and enhancing the dispersibility of the attapulgite clay in the epoxy matrix.

[0024] Preferably, the mass ratio of the attapulgite clay, the cerium nitrate hexahydrate, and the citric acid is 10:1.5-2.5:1-1.5.

[0025] (Three) Beneficial technical effects

[0026] The present application uses gamma-piperazinyl propyl methyl dimethoxysilane, isolated diene, chloropropionic acid and the like as raw materials to obtain a quaternary ammonium salt modified bisilane through Michael addition and quaternary ammonium reaction, and the preparation method is simple, the structure is novel, the silicon-oxygen bond contained therein is used to carry out grafting reaction with an epoxy resin to obtain a modified epoxy resin with large crosslinking density, and when the modified epoxy resin is added into a coating, not only the mechanical properties of the coating can be improved, but also the polycarboxyl structure contained in the modified epoxy resin can form a coordination bond with cerium ions on the surface of attapulgite, promoting the compatibility between attapulgite and the organic coating; on the other hand, the carboxyl structure can form a strong hydrogen bond with the surface of a PC plate substrate, further improving the adhesion of the coating to the PC plate. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] The dispersant is BYK-220S; the curing agent is curing agent T-31; the defoaming agent is defoaming agent Airex 900; and the film-forming aid is propylene glycol methyl ether acetate.

[0029] Embodiment 1

[0030] Step S1, under the protection of nitrogen, 80 mmol of gamma-piperazinyl propyl methyl dimethoxysilane, 40 mmol of 1,5-hexadiene and methanol are added into a flask, stirred and dispersed, the temperature is controlled to be 50 DEG C, and stirring reaction is carried out for 5 h; after the reaction is completed, rotary evaporation is carried out, and drying is carried out to obtain target product 1;

[0031] Step S2, 30 mmol of target product 1 and 160 mmol of chloropropionic acid are added into acetone, stirred and uniformly mixed, and warming reflux reaction is carried out for 8 h; after the reaction is completed, suction filtration is carried out, acetone washing is carried out, and recrystallization is carried out to obtain a quaternary ammonium salt modified bisilane;

[0032] Step S3, according to weight parts, 10 weight parts of attapulgite are dispersed in methanol, the temperature is controlled to be 60 DEG C, 2 weight parts of cerium nitrate hexahydrate and 1 weight part of citric acid are added into the mixture, stirring and mixing are carried out for 1 h, ammonia water is added to adjust the pH to be 8, and continuous stirring reaction is carried out for 4 h; after standing, centrifugation is carried out, deionized water washing is carried out until neutral, and drying is carried out to obtain a modified attapulgite;

[0033] Step S4, by weight parts, 20 parts by weight of epoxy resin E51, 1 part by weight of quaternary ammonium salt modified bisilane is added to a toluene acetone mixed solution with a mass ratio of 4:1, the temperature is controlled at 90℃, 0.2 parts by weight of deionized water and 0.11 parts by weight of dibutyltin dilaurate are added, stirring reaction for 7h, after the reaction is completed, rotary evaporation, to obtain a modified epoxy resin;

[0034] Step S5, by weight parts, 1 part by weight of modified attapulgite, 2 parts by weight of polycarbonate resin is added to deionized water, stirring and dispersing, then 20 parts by weight of epoxy resin E51 and 10 parts by weight of modified epoxy resin and 0.5 parts by weight of dispersing agent are added, stirring for 30min, finally 15 parts by weight of curing agent, 0.4 parts by weight of defoaming agent and 0.1 parts by weight of film forming aid are added, stirring for 30min, to obtain the paint.

[0035] Example 2

[0036] Step S1, under nitrogen protection, 85mmol of γ-piperazinyl propyl methyl dimethoxysilane, 40mmol of 1,6-heptadiene, methanol are added to a flask, stirring and dispersing, controlling the temperature at 45℃, stirring reaction for 7h, after the reaction is completed, rotary evaporation, drying, to obtain the target product 1;

[0037] Step S2, 30mmol of target product 1, 150mmol of chloropropionic acid are added to acetone, stirring and mixing uniformly, warming to reflux reaction for 10h, after the reaction is completed, suction filtration, acetone washing, recrystallization, to obtain the quaternary ammonium salt modified bisilane;

[0038] Step S3, by weight parts, 10 parts by weight of attapulgite is dispersed in methanol, controlling the temperature at 70℃, 2.5 parts by weight of cerium nitrate hexahydrate, 1.5 parts by weight of citric acid are added, stirring and mixing for 1h, then ammonia water is added to adjust the pH to 8, continuing stirring reaction for 6h, standing, centrifuging, deionized water washing to neutral, drying, to obtain the modified attapulgite;

[0039] Step S4, by weight parts, 20 parts by weight of epoxy resin (E51), 1.5 parts by weight of quaternary ammonium salt modified bisilane is added to a toluene acetone mixed solution with a mass ratio of 4:1, controlling the temperature at 95℃, 0.1 parts by weight of deionized water and 0.1 parts by weight of dibutyltin dilaurate are added, stirring reaction for 8h, after the reaction is completed, rotary evaporation, to obtain a modified epoxy resin;

[0040] Step S5, by weight, 2 parts by weight of modified attapulgite, 2 parts by weight of polycarbonate resin is added to deionized water, stirring and dispersing, then 20 parts by weight of epoxy resin E51 and 15 parts by weight of modified epoxy resin and 0.8 parts by weight of dispersant are added, stirring for 30 min, finally 13 parts by weight of curing agent, 0.3 parts by weight of defoaming agent and 0.5 parts by weight of film forming aid are added, stirring for 20 min, to obtain the paint.

[0041] Example 3

[0042] Step S1, under nitrogen protection, 88 mmol of γ-piperazinyl propyl methyl dimethoxy silane, 40 mmol of 1,7-octadiene, methanol are added to a flask, stirring and dispersing, controlling the temperature at 40℃, stirring for 7h, after the reaction is completed, rotary evaporation, drying, to obtain the target product 1;

[0043] Step S2, 30 mmol of target product 1, 180 mmol of chloropropionic acid are added to acetone, stirring and mixing uniformly, warming to reflux for 9h, after the reaction is completed, suction filtration, acetone washing, recrystallization, to obtain the quaternary ammonium salt modified disilane;

[0044] Step S3, by weight, 10 parts by weight of attapulgite is dispersed in methanol, controlling the temperature at 65℃, 1.5 parts by weight of cerium nitrate hexahydrate, 1.5 parts by weight of citric acid are added, stirring and mixing for 2h, then ammonia water is added to adjust the pH to 8, continuing to stir for 5h, standing, centrifuging, deionized water washing until neutral, drying, to obtain the modified attapulgite;

[0045] Step S4, by weight, 20 parts by weight of epoxy resin (E51), 2 parts by weight of quaternary ammonium salt modified disilane are added to a toluene-acetone mixed solution with a mass ratio of 4:1, controlling the temperature at 95℃, 0.15 parts by weight of deionized water and 0.12 parts by weight of dibutyltin dilaurate are added, stirring for 6h, after the reaction is completed, rotary evaporation, to obtain the modified epoxy resin;

[0046] Step S5, by weight, 3 parts by weight of modified attapulgite, 2 parts by weight of polycarbonate resin is added to deionized water, stirring and dispersing, then 20 parts by weight of epoxy resin E51 and 20 parts by weight of modified epoxy resin and 1 part by weight of dispersant are added, stirring for 30 min, finally 20 parts by weight of curing agent, 0.2 parts by weight of defoaming agent and 0.3 parts by weight of film forming aid are added, stirring for 25 min, to obtain the paint.

[0047] Comparative Example 1

[0048] The difference between this comparative example and Example 1 is that attapulgite is used instead of modified attapulgite in Step S5, and the rest of the steps are the same as Example 1.

[0049] Comparative Example 2

[0050] The difference between this comparative example and Example 1 is that no quaternary ammonium salt modified disilane is contained in step S4, and the remaining steps are the same as Example 1.

[0051] Comparative Example 3

[0052] The difference between this comparative example and Example 1 is that the target product 1 is used instead of the quaternary ammonium salt modified disilane in step S4, and the remaining steps are the same as Example 1.

[0053] Comparative Example 4

[0054] The difference between this comparative example and Example 1 is that no polycarbonate resin is contained in step S4, and the remaining steps are the same as Example 1.

[0055] Comparative Example 5

[0056] The difference between this comparative example and Example 1 is that a commercially available quaternary ammonium salt antibacterial agent is used instead of the quaternary ammonium salt modified disilane in step S4, and the remaining steps are the same as Example 1.

[0057] A clean PC glass plate is fixed on the platform, and the coating is slowly scraped on the substrate using a wire bar coater, and is cured, dried at room temperature to obtain a coating.

[0058] Referring to GB / T9286-2021, the adhesion grade of the coating to the PC glass plate is tested, and 0 is the best and 5 is the worst.

[0059] Table 1:

[0060]

[0061] As can be seen from the examples and Comparative Examples 2 and 3, the coating containing the quaternary ammonium salt disilane of the present application has good adhesion to the PC glass plate. In Comparative Example 3, no carboxyl group is contained, but its adhesion is still better than that of Comparative Example 2 which does not contain quaternary ammonium salt disilane. It is speculated that the reason may be that in Comparative Example 3, there is an incompletely reacted siloxane structure, which produces Si-OH after hydrolysis, which can form hydrogen bonds with the polar structure on the PC glass plate, thereby improving the adhesion of the coating to the PC glass plate. In Comparative Example 4, no polycarbonate resin is contained, and its adhesion is poorer than that of the example, because the polycarbonate resin has the same segment as the PC glass plate and has good compatibility, which can promote the adhesion of the epoxy resin coating to the PC glass plate, and Comparative Example 4 does not contain polycarbonate resin, so its adhesion is poor.

[0062] Referring to GB / T6739-2022, the hardness of the coating is tested by using a trolley pencil hardness tester, starting from a pencil with small hardness, and testing three times for the same hardness, and the highest hardness without scratches and cracks on the coating is the hardness of the coating.

[0063] The mechanical properties of the coating are tested by using an electronic universal material testing machine.

[0064] Table 2:

[0065]

[0066] As shown in the table, the epoxy coating prepared by the present application has excellent mechanical properties. The attapulgite in Comparative Example 1 is not modified and is easily agglomerated in the coating, thus seriously affecting the mechanical properties of the coating. Comparative Example 2 does not contain quaternary ammonium salt disilane, and the crosslinking density of the epoxy resin therein is low, so the mechanical properties are poor. Comparative Example 3 uses target product 1 instead of quaternary ammonium salt disilane, but does not contain a carboxyl group, and the carboxyl group can form hydrogen bonds with other components in the matrix, so the mechanical properties are not good.

[0067] The antibacterial performance is tested according to GB / T21866-2008, and the test bacteria are Escherichia coli and Staphylococcus aureus.

[0068] Table 3:

[0069]

[0070] As shown in the table, the epoxy coating of the present application still has good antibacterial performance for a long time, and when applied to a PC glass plate, it can have good antibacterial and bacterial contamination prevention effects.

[0071] The above content is only an example and description of the present application, and those skilled in the art can make various modifications or supplements or use similar ways to replace the described specific embodiments, as long as they do not deviate from the invention or exceed the scope defined by the present claims, and should belong to the protection scope of the present application.

Claims

1. A high-adhesion, high-hardness modified epoxy coating for PC glass sheets, characterized in that, The epoxy coating is prepared from the following raw materials in parts by weight: 20 parts epoxy resin, 10-20 parts modified epoxy resin, 15-20 parts curing agent, 1-3 parts modified attapulgite clay, 2 parts polycarbonate resin, 0.5-1 parts dispersant, 0.1-0.5 parts film-forming aid, 0.2-0.4 parts defoamer, and the balance being deionized water, totaling 100 parts by weight. The preparation method of the high-adhesion, high-hardness modified epoxy coating for PC glass panels includes the following steps: Step S1: Add epoxy resin E51 and quaternary ammonium salt modified bissilane to a toluene-acetone mixed solution with a mass ratio of 4:1, control the temperature at 90-95℃, add deionized water and dibutyltin dilaurate, stir and react for 6-8 hours. After the reaction is completed, rotary evaporate to obtain modified epoxy resin. Step S2: Add modified attapulgite clay and polycarbonate resin to deionized water, stir and disperse, then add epoxy resin, modified epoxy resin and dispersant, stir for 30 minutes, and finally add curing agent, defoamer and film-forming aid, stir for 20-30 minutes to obtain coating.

2. The high-adhesion, high-hardness modified epoxy coating for PC glass sheets according to claim 1, characterized in that, The mass ratio of the epoxy resin, quaternary ammonium salt modified bissilane, deionized water, and dibutyltin dilaurate is 100:5-10:0.5-1:0.5-0.

6.

3. The high-adhesion, high-hardness modified epoxy coating for PC glass sheets according to claim 1, characterized in that, The preparation method of the modified epoxy resin includes the following steps: Step S11: Under nitrogen protection, γ-piperazinylpropylmethyldimethoxysilane, isolated diene, and methanol are added to a flask, stirred and dispersed, and the temperature is controlled at 40-50℃. The reaction is stirred for 5-7 hours. After the reaction is completed, the product is rotary evaporated and dried to obtain the target product 1. Step S12: Add target product 1 and chloropropionic acid to acetone, stir and mix evenly, reflux for 8-10 hours. After the reaction is completed, filter, wash with acetone, recrystallize to obtain quaternary ammonium salt modified bissilane.

4. The high-adhesion, high-hardness modified epoxy coating for PC glass sheets according to claim 3, characterized in that, In step S11, the molar ratio of γ-piperazinylpropylmethyldimethoxysilane to isolated diene is 2-2.2:

1.

5. The high-adhesion, high-hardness modified epoxy coating for PC glass sheets according to claim 3, characterized in that, In step S11, the isolated diene is one of 1,5-hexadiene, 1,6-heptadiene, and 1,7-octadiene.

6. The high-adhesion, high-hardness modified epoxy coating for PC glass sheets according to claim 3, characterized in that, In step S12, the molar ratio of target product 1 to chloropropionic acid is 1:5-6.

7. The high-adhesion, high-hardness modified epoxy coating for PC glass sheets according to claim 1, characterized in that, The preparation method of the modified attapulgite includes the following steps: Attapulgite was dispersed in methanol at a controlled temperature of 60-70℃. Cerium nitrate hexahydrate and citric acid were added and stirred for 1-2 hours. Ammonia was then added to adjust the pH to 8, and the reaction was continued for 4-6 hours. The mixture was allowed to stand, centrifuged, washed with deionized water until neutral, and dried to obtain modified attapulgite.

8. The high-adhesion, high-hardness modified epoxy coating for PC glass sheets according to claim 7, characterized in that, The mass ratio of attapulgite, cerium nitrate hexahydrate, and citric acid is 10:1.5-2.5:1-1.5.

Images