Powder coating for glass and preparation method thereof

Abstract

The invention discloses a powder coating for glass and a preparation method thereof, and relates to the field of coatings. The powder coating for glass includes 50-70wt% polyamide resin, 4.0-5.7wt% curing agent, 1-1.5wt% polytetrafluoroethylene powder, 1-2wt% leveling agent, 0.3-0.5wt% degassing agent, 1-3wt% wetting agent, 9.5-10.5wt% densifier and 10-30wt% pigment filler; the polyamide resin includes a polyamide resin A and a polyamide resin B with a weight ratio of (1-1.5):1, the polyamide resin A adopts the esterification polycondensation product of 4,4'-diamino-2,2'-disulfonic acid diphenyl ether and dibasic acid under the action of Lewis acid catalyst, and the polyamide resin B adopts at least one of polyamide 6 and polyamide 66. The powder coating of the present application has good adhesion to the glass substrate, and the powder coating has strong stain resistance after film formation.

Description

Technical Field

[0001] The present application relates to the field of coatings, and in particular to a powder coating for glass and a preparation method thereof. Background Art

[0002] Powder coatings have been widely used in the field of industrial coatings due to their environmental protection, high efficiency and economic advantages. However, traditional powder coatings have weak adhesion on glass, mainly because the glass surface is smooth and chemically inert, making it difficult to form a strong chemical bond with the coating. In addition, powder coatings have poor film density after film formation and poor surface stain resistance, making them difficult to clean when applied to glass substrates such as dining tables. Summary of the invention

[0003] In order to improve the problems of poor adhesion of powder coatings to glass substrates and poor stain resistance of powder coatings after film formation in the relative technology, the present application provides a powder coating for glass and a preparation method thereof.

[0004] In the first aspect, the present application provides a powder coating for glass using the following technical solution:

[0005] A powder coating for glass, comprising 50-70wt% polyamide resin, 4.0-5.7wt% curing agent, 1-1.5wt% polytetrafluoroethylene powder, 1-2wt% leveling agent, 0.3-0.5wt% degassing agent, 1-3wt% wetting agent, 9.5-10.5wt% densifier and 10-30wt% pigment filler; wherein the polyamide resin comprises polyamide resin A and polyamide resin B in a weight ratio of (1-1.5):1, the polyamide resin A is an esterification polycondensation product of 4,4'-diamino-2,2'-disulfonic acid diphenyl ether and a dibasic acid under the action of a Lewis acid catalyst, and the polyamide resin B is at least one of polyamide 6 and polyamide 66.

[0006] In the present application, the powder coating for glass uses polyamide resin as a binder, and the polyamide resin uses a composition of a specific ratio of polyamide resin A and polyamide resin B, wherein polyamide resin A has a polar sulfonic acid group, which is conducive to improving the adhesion of the powder coating to the glass substrate, and the incorporation of polyamide resin B is conducive to improving the dispersion performance of polytetrafluoroethylene powder in polyamide resin. The curing agent is used to react with the polyamide resin to form a macromolecule with a network cross-linked structure, which is conducive to improving the adhesion of the powder coating to the glass substrate. The addition of polytetrafluoroethylene powder can provide a sandy surface feel of the coating, can increase the adhesion of the powder coating to the glass substrate, and can improve the anti-skid, scratch resistance and anti-reflective properties of the coating. The addition of leveling agent and degassing agent is mainly to prevent the occurrence of surface defects such as shrinkage cavities and orange peel during the film formation of the powder coating, which is conducive to improving the adhesion and stain resistance of the powder coating to the glass substrate. The role of the wetting agent is to enhance the wettability of the powder coating to the glass substrate and improve the adhesion between the powder coating and the glass substrate. The addition of densifier is mainly to reduce the porosity of powder coating film and improve the density of powder coating film. On the one hand, it improves the adhesion between powder coating and glass substrate, and on the other hand, it improves the stain resistance of powder coating film to oil, wine, vinegar, coffee, juice, etc. The addition of pigments and fillers can give the coating film the desired color or enhance the mechanical strength of the coating film, which can give the coating film beauty and durability.

[0007] In summary, the powder coating obtained in the present application with good adhesion to the glass substrate and good stain resistance depends on the coordination between the raw materials.

[0008] In some specific embodiments, the molar ratio of the 4,4'-diamino-2,2'-disulfonic acid diphenyl ether to the dibasic acid is 1:(1-1.1).

[0009] In some specific embodiments, the dibasic acid is a composition of adipic acid and terephthalic acid, and the molar ratio of adipic acid to terephthalic acid is 1:(3-4).

[0010] In the present application, the dibasic acid is a composition of adipic acid and terephthalic acid in a molar ratio of 1:(3-4), which is conducive to obtaining a powder coating with strong adhesion to the glass substrate and good heat resistance.

[0011] In some specific embodiments, the Lewis acid catalyst is an aluminum chloride aqueous solution or a zinc chloride aqueous solution with a mass concentration of 0.1-0.5%.

[0012] In some specific embodiments, the preparation method of the polyamide resin A is as follows:

[0013] Add 4,4'-diamino-2,2'-disulfonic acid diphenyl ether, dibasic acid and Lewis acid catalyst into tetrahydrofuran, mix well, heat to 50-55°C, react for 0.5-1h, then heat to 280-300°C, react for 2-3h, remove water from the reaction system during the reaction, cool and crush after the reaction is completed to obtain polyamide resin A.

[0014] In the present application, the polyamide resin A prepared by the above method has good wettability to the glass substrate, which is beneficial to improving the adhesion between the powder coating and the glass substrate.

[0015] In some specific embodiments, the wetting agent is an organic silicon-oxygen copolymer.

[0016] In the present application, an organic silicon-oxygen copolymer is used as a wetting agent. The organic silicon-oxygen copolymer has good thermal stability and is not easy to volatilize or degrade during processing, and can effectively improve the wettability of the powder coating to the glass substrate.

[0017] In some specific embodiments, the curing agent is triglycidyl isocyanurate.

[0018] In some specific embodiments, the particle size of the polytetrafluoroethylene powder is in the range of 1-10 μm, and the densifier is aluminum hydroxide.

[0019] The particle size range of polytetrafluoroethylene micropowder is controlled within 1-10 μm, which is conducive to the uniform dispersion of polytetrafluoroethylene micropowder. In addition, the densifier is aluminum hydroxide, which has both densification and fireproofing effects.

[0020] In a second aspect, the present application provides a method for preparing a powder coating for glass using the following technical solution:

[0021] A method for preparing a powder coating for glass comprises the following steps:

[0022] S1, mixing the polyamide resin, curing agent, polytetrafluoroethylene powder, leveling agent, degassing agent, wetting agent, densifying agent and pigment and filler to obtain a premix;

[0023] S2, melt-extrude, cool and crush the premix to obtain a resin masterbatch;

[0024] S3, melt-extrude the resin masterbatch, cool it, and crush it again to obtain a powder coating for glass.

[0025] In the present application, after the raw materials in the powder coating for glass are mixed, the powder coating is preferably prepared by a two-step melt extrusion method, which is beneficial to improving the density and stain resistance of the powder coating.

[0026] In some specific embodiments, the melting temperature in step S2 is 120-125°C, and the melting temperature in step S3 is 110-115°C.

[0027] In the present application, the addition of polytetrafluoroethylene powder and the control of the temperature in steps S2 and S3 are beneficial to the uniform dispersion of the raw materials, and the powder coating can also obtain a sandy surface after film formation, thereby improving the anti-slip, scratch resistance and anti-reflection properties of the coating.

[0028] In summary, this application at least includes the following technical effects:

[0029] (1) The present application adopts a specific ratio of polyamide resin A, polyamide resin B, curing agent, polytetrafluoroethylene powder, leveling agent, degassing agent, wetting agent, densifying agent and pigment filler, wherein polyamide resin A is an esterification polycondensation product of 4,4'-diamino-2,2'-disulfonic acid diphenyl ether and a dibasic acid under the action of a Lewis acid catalyst, and polyamide resin B is at least one of polyamide 6 and polyamide 66. The present application can effectively improve the adhesion between the powder coating and the glass substrate, and can also improve the stain resistance of the powder coating after film formation.

[0030] (2) In the present application, after the raw materials in the powder coating for glass are mixed, the powder coating is preferably prepared by a two-step melt extrusion method, which is beneficial to improving the density and stain resistance of the powder coating.

[0031] (3) In the present application, the addition of polytetrafluoroethylene powder and the control of the temperature in steps S2 and S3 are beneficial to the uniform dispersion of the raw materials and the powder coating can obtain a sandy surface after film formation, thereby improving the anti-slip, scratch resistance and anti-reflection properties of the coating. DETAILED DESCRIPTION

[0032] The following is a further explanation based on specific experiments.

[0033] Example

[0034] [Example 1]

[0035] A powder coating for glass, comprising 50wt% polyamide resin, 4wt% triglycidyl isocyanurate, 1wt% polytetrafluoroethylene powder (DuPont, HH2010AFPTOK, USA), 2wt% leveling agent (BYK-333 leveling agent, Germany), 0.5wt% degassing agent (Clariant, 9615A), 3wt% wetting agent (RK-8209, Ruike Chemical), 9.5wt% densifier (aluminum hydroxide) and 30wt% color filler (nano titanium dioxide).

[0036] The polyamide resin is a composition of polyamide resin A and polyamide resin B, the weight ratio of polyamide resin A to polyamide resin B is 1:1; polyamide resin A is an esterification polycondensation product of 4,4'-diamino-2,2'-disulfonic acid diphenyl ether and a dibasic acid under the action of a Lewis acid catalyst, and polyamide resin B is polyamide 66 (DuPont, 80G33HS1L).

[0037] The preparation method of polyamide resin A comprises the following steps:

[0038] 10 kmol 4,4'-diamino-2,2'-disulfonic acid diphenyl ether, 10 kmol adipic acid, and 1 kg of 0.1% aluminum chloride aqueous solution were added to 10 kg of tetrahydrofuran, mixed evenly, heated to 50°C, reacted for 1 hour, then heated to 280°C, reacted for 3 hours, and water in the reaction system was removed simultaneously during the reaction. After the reaction was completed, the mixture was cooled and crushed to obtain polyamide resin A.

[0039] In addition, in this embodiment, the preparation method of the powder coating for glass comprises the following steps:

[0040] S1. Evenly mix polyamide resin, curing agent, polytetrafluoroethylene powder, leveling agent, degassing agent, wetting agent, densifying agent and pigment and filler to obtain a premix;

[0041] S2, melt-extrude the premix at 120-125°C, cool, and crush to obtain a resin masterbatch;

[0042] S3. Melt and extrude the resin masterbatch at 110-115° C., cool it, and crush it again to obtain a powder coating for glass.

[0043] [Example 2]

[0044] A powder coating for glass, comprising 60wt% polyamide resin, 5wt% triglycidyl isocyanurate, 1.1wt% polytetrafluoroethylene powder (Japan Daikin, L-2), 1.5wt% leveling agent (Germany BYK-333 leveling agent), 0.4wt% degassing agent (Urisin, NEW-0400), 2wt% wetting agent (Meside, MSD-4806), 10wt% densifier (aluminum hydroxide) and 20wt% color filler (nano titanium dioxide).

[0045] The polyamide resin is a composition of polyamide resin A and polyamide resin B, the weight ratio of polyamide resin A to polyamide resin B is 1:1; polyamide resin A is an esterification polycondensation product of 4,4'-diamino-2,2'-disulfonic acid diphenyl ether and a dibasic acid under the action of a Lewis acid catalyst, and polyamide resin B is polyamide 6 (BASF, B3UQ721).

[0046] In this embodiment, the preparation method of polyamide resin A comprises the following steps:

[0047] 10 kmol 4,4'-diamino-2,2'-disulfonic acid diphenyl ether, 10.5 kmol adipic acid, and 1 kg of 0.3% aluminum chloride aqueous solution were added to 10 kg of tetrahydrofuran, mixed evenly, heated to 52°C, reacted for 0.8 h, then heated to 290°C, reacted for 2.5 h, and water in the reaction system was removed simultaneously during the reaction. After the reaction was completed, the mixture was cooled and crushed to obtain polyamide resin A.

[0048] In addition, in this embodiment, the preparation method of the powder coating for glass comprises the following steps:

[0049] S1. Evenly mix polyamide resin, curing agent, polytetrafluoroethylene powder, leveling agent, degassing agent, wetting agent, densifying agent and pigment and filler to obtain a premix;

[0050] S2, melt-extrude the premix at 120-125°C, cool, and crush to obtain a resin masterbatch;

[0051] S3. Melt and extrude the resin masterbatch at 110-115° C., cool it, and crush it again to obtain a powder coating for glass.

[0052] [Example 3]

[0053] A powder coating for glass, comprising 70wt% polyamide resin, 5.7wt% triglycidyl isocyanurate, 1.5wt% polytetrafluoroethylene powder (DuPont, HH2010AFPTOK, USA), 1wt% leveling agent (TEGO Glide450), 0.3wt% degassing agent (Clariant, 9615A), 1wt% wetting agent (Meside, MSD-4806), 10.5wt% densifier (aluminum hydroxide) and 10wt% pigment filler (nano titanium dioxide).

[0054] The polyamide resin is a composition of polyamide resin A and polyamide resin B, the weight ratio of polyamide resin A to polyamide resin B is 1.5:1; polyamide resin A is an esterification polycondensation product of 4,4'-diamino-2,2'-disulfonic acid diphenyl ether and a dibasic acid under the action of a Lewis acid catalyst, and polyamide resin B is polyamide 6 (BASF, B3UQ721).

[0055] In this embodiment, the preparation method of polyamide resin A comprises the following steps:

[0056] 10 kmol 4,4'-diamino-2,2'-disulfonic acid diphenyl ether, 11 kmol adipic acid, and 1 kg of 0.5% aluminum chloride aqueous solution were added to 10 kg of tetrahydrofuran, mixed evenly, heated to 55°C, reacted for 0.5 h, then heated to 300°C, reacted for 2 h, and water in the reaction system was removed simultaneously during the reaction. After the reaction was completed, the mixture was cooled and crushed to obtain polyamide resin A.

[0057] In addition, in this embodiment, the preparation method of the powder coating for glass comprises the following steps:

[0058] S1. Evenly mix polyamide resin, curing agent, polytetrafluoroethylene powder, leveling agent, degassing agent, wetting agent, densifying agent and pigment and filler to obtain a premix;

[0059] S2, melt-extrude the premix at 120-125°C, cool, and crush to obtain a resin masterbatch;

[0060] S3. Melt and extrude the resin masterbatch at 110-115° C., cool it, and crush it again to obtain a powder coating for glass.

[0061] [Example 4]

[0062] A powder coating for glass, which is different from [Example 1] in that the dibasic acid used in preparing the polyamide resin is different. In this example, the dibasic acid is terephthalic acid.

[0063] In this embodiment, the preparation method of polyamide resin A comprises the following steps:

[0064] 10 kmol 4,4'-diamino-2,2'-disulfonic acid diphenyl ether, 10 kmol terephthalic acid, and 1 kg of 0.1% aluminum chloride aqueous solution were added to 10 kg of tetrahydrofuran, mixed evenly, heated to 50°C, reacted for 1 hour, then heated to 280°C, reacted for 3 hours, and water in the reaction system was removed simultaneously during the reaction. After the reaction was completed, the mixture was cooled and crushed to obtain polyamide resin A.

[0065] [Example 5]

[0066] A powder coating for glass, which is different from [Example 1] in that the dibasic acid used in preparing the polyamide resin is different. In this embodiment, the dibasic acid is a combination of adipic acid and terephthalic acid, and the molar ratio of adipic acid to terephthalic acid is 1:4.

[0067] In this embodiment, the preparation method of polyamide resin A comprises the following steps:

[0068] 10 kmol 4,4'-diamino-2,2'-disulfonic acid diphenyl ether, 2.5 kmol adipic acid, 7.5 kmol terephthalic acid, and 1 kg of 0.1% aluminum chloride aqueous solution were added to 10 kg of tetrahydrofuran, mixed evenly, heated to 50°C, reacted for 1 hour, then heated to 280°C, reacted for 3 hours, and water in the reaction system was removed simultaneously during the reaction. After the reaction was completed, the mixture was cooled and crushed to obtain polyamide resin A.

[0069] [Example 6]

[0070] A powder coating for glass, which is different from [Example 5] in that the temperature controlled in step S2 during the preparation of the powder coating for glass is different. In this embodiment, the temperature controlled in step S2 is 145-150°C.

[0071] [Example 7]

[0072] A powder coating for glass, which is different from [Example 5] in that the temperature controlled in step S3 during the preparation of the powder coating for glass is different. In this embodiment, the temperature controlled in step S3 is 145-150°C.

[0073] Comparative Example

[0074] [Comparative Example 1]

[0075] A powder coating for glass, which differs from [Example 1] in that polyamide resin is all polyamide resin A.

[0076] [Comparative Example 2]

[0077] A powder coating for glass, which differs from [Example 1] in that: the polyamide resin is all polyamide 66 (DuPont, 80G33HS1L).

[0078] Performance testing

[0079] 1. Adhesion: The adhesion between the coating formed by the powder coating in each embodiment and comparative example and the glass substrate was tested using a QEZ-II adhesion tester. The coating thickness was 10 μm. The test results were calculated using the hundred grid method. The test results are recorded in Table 1. The test results are expressed as 100 / A. The closer the value of A is to 100, the better the adhesion. The heat treatment was performed in boiling water at 100°C for 2 hours.

[0080] 2. Stain resistance: Pour equal amounts of coffee, vinegar or juice on the coatings formed by the powder coatings in each embodiment and comparative example, let stand for 48 hours in an environment of 30°C, then wipe with a wet cloth that has been wrung out for 30 seconds. After 30 seconds, observe whether there are any residual stains on the coatings.

[0081] 3. Gloss: With reference to the standard GB / T 9754-2007 "Paint films of paints and varnishes without metallic pigments", the 3nh multi-angle precision gloss meter NHG268 was used for detection, the test angle was 60°, 5 samples of each embodiment and comparative example were taken for testing, and the average gloss and standard deviation were calculated. Among them, when the gloss is in the range of 40-60GU, the film surface is soft and non-reflective.

[0082] Table 1

[0083]

[0084] Combining Example 1 with Comparative Example 1 and the data in Table 1, it can be seen that using polyamide resin A alone as the polyamide resin is not conducive to the uniform dispersion of polytetrafluoroethylene powder, the glossiness of different positions of the coating varies greatly, and stains are easily left.

[0085] Combining Example 1 with Comparative Example 2 and according to the data in Table 1, it can be seen that when the polyamide resin is polyamide resin B alone, the adhesion between the powder coating and the glass substrate is poor.

[0086] Combining Example 1 with Examples 4-5 and the data in Table 1, it can be seen that the dibasic acid using a composition of adipic acid and terephthalic acid in a molar ratio of 1:(3-4) is conducive to obtaining a powder coating with strong adhesion to the glass substrate and good heat resistance.

[0087] Combining Examples 5-7 and the data in Table 1, it can be seen that when preparing powder coatings for glass, the temperature in steps S2 and S3 should not be too high, otherwise the glossiness will increase significantly, which is not conducive to obtaining a powder coating with a soft and non-reflective film surface.

[0088] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A powder coating for glass, characterized in that: The invention comprises 50-70wt% polyamide resin, 4.0-5.7wt% curing agent, 1-1.5wt% polytetrafluoroethylene powder, 1-2wt% leveling agent, 0.3-0.5wt% degassing agent, 1-3wt% wetting agent, 9.5-10.5wt% densifier and 10-30wt% pigment and filler; wherein the polyamide resin comprises polyamide resin A and polyamide resin B in a weight ratio of (1-1.5):1, and the polyamide resin A is The invention discloses an esterification polycondensation product of 4,4'-diamino-2,2'-disulfonic acid diphenyl ether and a dibasic acid under the action of a Lewis acid catalyst, wherein the polyamide resin B is at least one of polyamide 6 and polyamide 66; the molar ratio of the 4,4'-diamino-2,2'-disulfonic acid diphenyl ether to the dibasic acid is 1:(1-1.1); the dibasic acid is a combination of adipic acid and terephthalic acid, and the molar ratio of adipic acid to terephthalic acid is 1:(3-4).

2. A powder coating for glass according to claim 1, characterized in that: The Lewis acid catalyst is an aluminum chloride aqueous solution or a zinc chloride aqueous solution with a mass concentration of 0.1-0.5%.

3. A powder coating for glass according to any one of claims 1-2, characterized in that: The preparation method of the polyamide resin A is as follows: Add 4,4'-diamino-2,2'-disulfonic acid diphenyl ether, dibasic acid and Lewis acid catalyst into tetrahydrofuran, mix well, heat to 50-55°C, react for 0.5-1h, then heat to 280-300°C, react for 2-3h, remove water from the reaction system during the reaction, cool and crush after the reaction is completed to obtain polyamide resin A.

4. A powder coating for glass according to any one of claims 1-2, characterized in that: The wetting agent is an organic silicon-oxygen copolymer.

5. A powder coating for glass according to any one of claims 1-2, characterized in that: The curing agent is triglycidyl isocyanurate.

6. A powder coating for glass according to any one of claims 1-2, characterized in that: The particle size of the polytetrafluoroethylene powder is in the range of 1-10 μm, and the densifier is aluminum hydroxide.

7. The method for preparing a powder coating for glass according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, mixing the polyamide resin, curing agent, polytetrafluoroethylene powder, leveling agent, degassing agent, wetting agent, densifying agent and pigment and filler to obtain a premix; S2, melt-extrude, cool and crush the premix to obtain a resin masterbatch; S3, melt-extrude the resin masterbatch, cool it, and crush it again to obtain a powder coating for glass.

8. The method for preparing a powder coating for glass according to claim 7, characterized in that: The melting temperature in step S2 is 120-125°C, and the melting temperature in step S3 is 110-115°C.

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