Anti-round hole primer and its preparation method and application

Abstract

The present invention relates to the technical field of optical polyurethane varnishes, in particular to the field of IPC C09D175, and more specifically to an anti-round hole primer and its preparation method and application. The raw materials include component A and component B, and the weight ratio of component A to component B is 1:(0.1-0.7); wherein the raw materials of component A, by weight percentage, include: 10-40% alkyd resin, 1-15% aldehyde-ketone resin, 10-20% nitrocellulose, 0.1-5% auxiliary agent, 3-8% cellulose organic acid ester, and solvent makes up the balance; the raw materials of component B, by weight percentage, include: 40-60% solvent, 0.1-2% dehydrating agent, and TDI curing agent makes up the balance. The alkyd resin has a solid content of 70-85 wt% and a hydroxyl value of 130-160 mg KOH / g, which can effectively prevent the formation of round holes in the coating. The aldehyde-ketone resin has a softening point of 105-150°C, a glass transition temperature of 85-120°C, and a hydroxyl value of 300-400 mg KOH / g, which can improve the hardness and gloss of the coating.

Description

Technical Field

[0001] The present invention relates to the technical field of light polyurethane varnish, in particular to the field of IPC C09D175 / , and more specifically to an anti-round hole primer, a preparation method and application thereof. Background Art

[0002] Most existing wood products use PE or UV transparent primers, which offer dull colors and poor layering and three-dimensionality. In contrast, PU primers offer vibrant colors and a strong decorative effect, and are therefore gaining market favor. However, conventional PU primers are prone to blistering, especially in the recent surge in popularity of custom-made solid wood furniture. This impact is particularly pronounced when painting these surfaces. The inability to remove bubbles trapped in the wood pores can easily lead to coating defects such as round holes, fish-eye bubbles, sagging, or bulging.

[0003] CN102070980B discloses a yew polyurethane paint, made by mixing a base paint, a curing agent, and a diluent in a weight ratio of 1:0.5:0.4. This invention utilizes multiple, composite injections of a paclitaxel factor to achieve a polyurethane paint product with high hardness, fullness, adhesion, high-temperature tack resistance, water resistance, and excellent workability. The paint also rapidly decomposes and absorbs organic compounds such as formaldehyde. However, its anti-round hole performance was not studied. Summary of the Invention

[0004] The first aspect of the present invention provides an anti-round hole sealing primer, the raw materials of which include component A and component B, wherein the weight ratio of component A to component B is 1:(0.1-0.7);

[0005] Preferably, the weight ratio of component A to component B is 1:(0.3-0.5).

[0006] Further preferably, the weight ratio of component A to component B is 1:0.5.

[0007] The raw materials of component A include, by weight percentage, 10-40% alkyd resin, 1-15% aldehyde-ketone resin, 10-20% nitrocellulose, 0.1-5% additive, 3-8% cellulose organic acid ester, and the balance is made up of solvent; the raw materials of component B include, by weight percentage, 40-60% solvent, 0.1-2% dehydrating agent, and the balance is made up of TDI curing agent.

[0008] Preferably, the raw materials of component A include, by weight percentage, 10-40% alkyd resin, 1-15% aldehyde-ketone resin, 10-20% nitrocellulose, 0.1-5% additive, 3-8% cellulose organic acid ester, and the balance is made up of solvent; the raw materials of component B include, by weight percentage, 40-60% solvent, 0.1-2% dehydrating agent, and the balance is made up of TDI curing agent.

[0009] Preferably, the raw materials of component A include, by weight percentage, 20-30% alkyd resin, 5-10% aldehyde-ketone resin, 10-20% nitrocellulose, 0.1-3% additive, 3-6% cellulose organic acid ester, and the balance is made up of solvent; the raw materials of component B include, by weight percentage, 45-55% solvent, 0.1-1% dehydrating agent, and the balance is made up of TDI curing agent.

[0010] Further preferably, the raw materials of component A include, by weight percentage, 30% alkyd resin, 8% aldehyde-ketone resin, 15% nitrocellulose, 1% additive, 5% cellulose organic acid ester, and the solvent makes up the balance; the raw materials of component B include, by weight percentage, 49.5% solvent, 0.5% dehydrating agent, and TDI curing agent makes up the balance.

[0011] Preferably, the alkyd resin has a solid content of 75-85 wt % and a hydroxyl value of 120-180 mg KOH / g.

[0012] Preferably, the alkyd resin comprises a synthetic fatty acid resin.

[0013] Preferably, the alkyd resin includes at least one of AK2330, AK2380B, 3755-X-80, 3759-B-80, 2530X80C, 3880, and 3862-60.

[0014] Preferably, the alkyd resin has a solid content of 70-85 wt % and a hydroxyl value of 130-160 mg KOH / g.

[0015] Further preferably, the alkyd resin is purchased from Changxing Chemical, brand: ETERKYD 3755-X-80.

[0016] The aldehyde-ketone resin has a softening point of 105-150° C., a glass transition temperature of 85-120° C., and a hydroxyl value of 300-400 mg KOH / g.

[0017] Preferably, the aldehyde-ketone resin has a softening point of 105-120° C., a glass transition temperature of 85-95° C., and a hydroxyl value of 300-340 mg KOH / g.

[0018] Further preferably, the aldehyde-ketone resin is purchased from Shanghai Kaiyin Chemical Co., Ltd., brand: Evonik, trademark: Variplus SK.

[0019] The cellulose organic acid ester includes at least one of cellulose acetate butyrate, cellulose acetate, cellulose acetate propionate, cellulose acetate phthalate, and cellulose acetate succinate.

[0020] Preferably, the cellulose organic acid ester includes cellulose acetate butyrate.

[0021] Preferably, the acetyl content in the cellulose acetate butyrate is 10-20 wt % and the glass transition temperature is 125-135° C.

[0022] During the drying process, the coating film is mixed with bubbles and solvent vapor, which requires a certain amount of time and channels to fully escape the coating. If the coating surface dries too quickly, a soft film will form on the coating surface, and the tiny pores will close, hindering the free volatilization of bubbles and solvent vapor under the coating. This will cause the bubbles and solvent vapor in the coating to be blocked or rise slowly during the rise and escape process, forming a certain air pressure that will lift or break the coating film, forming round holes. The applicant has found that the alkyd resin solid content of 70-85wt% and the hydroxyl value of 130-160mg KOH / g can effectively avoid the formation of round holes after the coating film is formed. This may be because the alkyd resin with a specific hydroxyl value is compounded with a curing agent to balance the surface drying and curing time. As the resin hydroxyl value increases, the concentration of the system hydroxyl group increases accordingly, the reaction of -NCO and -OH is accelerated, the pot life shortens, the surface drying becomes faster, and the number of crosslinking points increases after the coating film is formed, the crosslinking density increases, and the hardness improves. However, since the open state time of the coating surface shortens, bubbles are easily enclosed in the coating film, exacerbating the formation of round holes.

[0023] The applicant further discovered that the aldehyde-ketone resin has a softening point of 105-150°C, a glass transition temperature of 85-120°C, and a hydroxyl value of 300-400 mg KOH / g, which can improve the hardness and gloss of the coating. This may be due to the compounding of an aldehyde-ketone resin with a specific glass transition temperature and an alkyd resin with a specific hydroxyl value, which shortens the surface drying time and increases the solvent release. At the same time, it forms a specific network structure with a specific curing agent, thereby increasing the bubble discharge channel.

[0024] Further preferably, the cellulose acetate butyrate has an acetyl content of 13.5 wt % and a glass transition temperature of 130° C., and is purchased from Shanghai Kaiyin Chemical Co., Ltd., brand: Eastman, grade: CAB-381-0.5.

[0025] The solvent includes at least one of butyl acetate, ethyl acetate, dimethyl carbonate, and propylene glycol methyl ether acetate.

[0026] Preferably, the ambient temperature is lower than 25° C., and the solvent includes butyl acetate and ethyl acetate, and the weight ratio of butyl acetate to ethyl acetate is (1-4):2.

[0027] Preferably, the ambient temperature is lower than 25° C., and the solvent includes butyl acetate and ethyl acetate, and the weight ratio of butyl acetate to ethyl acetate is 2:1.

[0028] Preferably, the ambient temperature is not lower than 25° C., and the solvent includes butyl acetate.

[0029] The weight ratio of the alkyd resin, the aldehyde-ketone resin and the nitrocellulose is (10-30): (6-12): (10-20).

[0030] Preferably, the weight ratio of the alkyd resin, the aldehyde-ketone resin and the nitrocellulose is 30:8:15.

[0031] The dehydrating agent is selected from at least one of dehydrating agent 902, dehydrating agent BF-5, and dehydrating agent G-180; preferably, the dehydrating agent is dehydrating agent BF-5 (Bayer, Germany).

[0032] The auxiliary agent includes at least one of a dispersant, a defoaming agent, and a leveling agent.

[0033] Preferably, the auxiliary agent comprises a combination of a dispersant, a defoamer and a leveling agent, and the weight ratio of the dispersant, the defoamer and the leveling agent is 1: (0-0.4): (0-0.2).

[0034] The applicant has discovered that a weight ratio of the dispersant, defoamer, and leveling agent of 1:(0-0.4):(0-0.2) can further enhance the anti-round-hole effect while also improving the coating's appearance and workability. During the primer film-forming process, as the solvent evaporates, the surface viscosity of the coating gradually increases, and the density and tension of the coating surface also increase accordingly, causing it to sink to the bottom. The bottom of the coating contains more solvent and has lower surface tension, which creates a driving force that pushes the bottom coating upward, forming Bénard vortices and causing phase separation in the system, resulting in blooming and whitening. Using a specific proportion of dispersant can promote alkyd resin to fully and quickly wet the wood surface, eliminate microbubbles on the inner surface of the wood duct, so that the associative group of the alkyd resin at one end of the dispersant can be combined with the hydroxyl and carboxyl groups on the alkyd resin molecules to obtain a certain associative structure, forming a larger macromolecular overall structure, so that it and the aldehyde-ketone resin can be evenly distributed in the coating system to avoid adverse phenomena such as sedimentation or agglomeration between the systems, ensuring that the matt varnish has good storage stability and can also more effectively wet the substrate during spraying. In order to obtain a good defoaming effect, the defoamer needs to be incompatible with the coating system, but it is easy to cause shrinkage cavities and fogging defects, affecting the transparency of the coating film. The present application uses a specific proportion of defoamer to obtain a good defoaming effect and does not affect the uniformity of the coating film.

[0035] Preferably, the weight ratio of the dispersant, defoaming agent and leveling agent is 1:0.2:0.1.

[0036] The type of the dispersant is not particularly limited. Preferably, the dispersant is selected from at least one of EFKA4010, BYK110, and BYK103; more preferably, the dispersant is BYK103 (BYK Chemical).

[0037] The type of the defoaming agent is not particularly limited. Preferably, the defoaming agent is selected from at least one of BYK052, BYK066N, BYK141, BYK8800, AC270, AC300, and HX2300. More preferably, the defoaming agent is BYK052 (BYK Chemical).

[0038] The type of the leveling agent is not particularly limited. Preferably, the leveling agent is selected from at least one of BYK358N, BYK333, BYK323, TEGO450, and EFKA3777; more preferably, the leveling agent is BYK333 (BYK Chemical).

[0039] The TDI curing agent is selected from at least one of Covestro L-75, Dongxu L-75, and Wanhua L-75.

[0040] Preferably, the TDI curing agent is selected from Covestro L-75.

[0041] The second aspect of the present invention provides a preparation method of an anti-round hole sealing primer, comprising the following steps: adding an alkyd resin, an aldehyde-ketone resin, nitrocellulose, an additive, and a cellulose organic acid ester to a solvent, mixing and stirring uniformly to obtain component A; adding a dehydrating agent and a TDI curing agent to the solvent and stirring uniformly to obtain component B; and mixing components A and B to obtain.

[0042] A third aspect of the present invention provides an application of an anti-round hole sealing primer, which is applied to solid wood products.

[0043] Preferably, it is applied to solid wood furniture.

[0044] The main factors of spraying are that the paint volume is too large, the wetting and solubility of the coating is poor, it is easy to form partial agglomeration, resulting in pitting, insufficient solubility of the paint thinner, incompatible substances are precipitated in the late evaporation of the solvent, the viscosity of the paint is too high, the pinholes caused by too thick a coating at one time, or the improper use of the modifier, the fine bubbles at the bottom rise but do not crack.

[0045] However, high-end solid wood furniture often uses porous woods with deep pores, such as sapele, cassila, ash, and rosewood. These deep pores can easily cause large bubbles to form after polyurethane primer is applied to the wood. These bubbles then penetrate the wood, creating pinholes that are difficult to fill. The thicker the paint film, the deeper the pinholes. To address this problem, the polyurethane primer must quickly penetrate the wood grain before the paint film dries, expelling all trapped air and preventing large topcoat bubbles. Without bubbles, pinholes will be eliminated after sanding.

[0046] Beneficial effects:

[0047] 1. The alkyd resin has a solid content of 70-85 wt % and a hydroxyl value of 130-160 mg KOH / g, which can effectively avoid the appearance of round holes after coating and meet the use requirements of solid wood products.

[0048] 2. The aldehyde-ketone resin has a softening point of 105-150°C, a glass transition temperature of 85-120°C, and a hydroxyl value of 300-400 mg KOH / g, which can improve the hardness and glossiness of the coating.

[0049] 3. The weight ratio of the dispersant, defoamer and leveling agent is 1: (0-0.4): (0-0.2), which can further improve the anti-round hole effect and improve the appearance and construction performance of the coating.

[0050] 4. The cellulose acetate butyrate has an acetyl content of 10-20 wt % and a glass transition temperature of 125-135° C., which can improve the wettability of the solvent to the system components and control the surface dry time within 35 minutes. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a spray test of the anti-circular hole sealing primer prepared in Example 1.

[0052] Figure 2 This is a spray test of the anti-circular hole sealing primer prepared in Example 2.

[0053] Figure 3 This is a spray test of the anti-circular hole sealing primer prepared in Example 3.

[0054] Figure 4 This is a spray test of the anti-circular hole sealing primer prepared in Example 4.

[0055] Figure 5 This is a spray test of the anti-round hole sealing primer prepared in Example 5. DETAILED DESCRIPTION

[0056] Example 1

[0057] A pore-proof sealing primer comprises raw materials of component A and component B, wherein the weight ratio of component A to component B is 1:0.5; the raw materials of component A, calculated by weight percentage, are: 30% alkyd resin, 8% aldehyde-ketone resin, 15% nitrocellulose, 1% auxiliary agent, 5% cellulose organic acid ester, with the balance being made up of solvent; the raw materials of component B, calculated by weight percentage, are: 49.5% solvent, 0.5% dehydrating agent, with the balance being made up of TDI curing agent.

[0058] The alkyd resin was purchased from Changxing Chemical Industry, with the brand name: ETERKYD 3755-X-80.

[0059] The aldehyde-ketone resin was purchased from Shanghai Kaiyin Chemical Co., Ltd., brand: Evonik, grade: VariplusSK.

[0060] The nitrocellulose is 1 / 16 second nitrocellulose purchased from Northern Nitrocellulose Co., Ltd.

[0061] The cellulose organic acid ester is cellulose acetate butyrate, the cellulose acetate butyrate has an acetyl content of 13.5 wt %, a glass transition temperature of 130° C., and is purchased from Shanghai Kaiyin Chemical Co., Ltd., brand: Eastman, grade: CAB-381-0.5.

[0062] The solvent is butyl acetate.

[0063] The dehydrating agent is dehydrating agent BF-5 (Bayer, Germany).

[0064] The weight ratio of the dispersant, defoamer and leveling agent is 1:0.2:0.1; the defoamer is BYK052 (BYK Chemical); the leveling agent is BYK333 (BYK Chemical); and the dispersant is BYK103 (BYK Chemical).

[0065] The TDI curing agent is Covestro L-75.

[0066] A preparation method of an anti-round hole sealing primer comprises the following steps: adding alkyd resin, aldehyde-ketone resin, nitrocellulose, an additive, and cellulose organic acid ester to a solvent, and mixing and stirring uniformly to obtain component A; adding a dehydrating agent and a TDI curing agent to the solvent and stirring uniformly to obtain component B; and mixing components A and B to obtain the product.

[0067] The invention discloses an application of an anti-round hole sealing primer for solid wood furniture.

[0068] Example 2

[0069] The specific implementation is the same as that of Example 1; the difference is that in Example 2: the alkyd resin is purchased from Tongde Chemical, model AK2380B.

[0070] Example 3

[0071] The specific implementation method is the same as that of Example 1; except that, in Example 3, the aldehyde-ketone resin is purchased from Shanghai Kaiyin Chemical Co., Ltd., brand: Evonik, trademark: VariPlus TC.

[0072] Example 4

[0073] The specific implementation is the same as in Example 1; the difference is that in Example 4: purchased from Shanghai Kaiyin Chemical Co., Ltd., brand: Eastman, grade: CAB-551-0.2.

[0074] Example 5

[0075] The specific implementation is the same as that of Example 1; the difference is that in Example 5: the weight ratio of the dispersant, defoaming agent and leveling agent is 1:0.2:0.15.

[0076] Performance test methods and results

[0077] 1. The anti-round hole sealing primer prepared in Example 1 was tested for the following properties. The test results are shown in Table 1.

[0078] Table 1

[0079]

[0080] 2. The anti-hole sealing primer prepared in Examples 1 to 5 was sprayed and tested for appearance observation. Figure 1-5 As shown, the evaluation is divided into excellent anti-hole effect, average anti-hole effect, and poor anti-hole effect. The anti-hole test is to spray two "cross" shapes normally and observe the number of holes on the solid wood board. Excellent: 0-3 round holes; Good: 3-8 round holes; Poor: more than 8 round holes.

[0081] The test results are shown in Table 2.

[0082] Table 2

[0083] Example Anti-round hole effect Example 1 excellent Example 2 good Example 3 good Example 4 Difference Example 5 good

Claims

1. An anti-round hole sealing primer, characterized in that: The raw materials include component A and component B, and the weight ratio of component A to component B is 1:(0.1-0.7); wherein, the raw materials of component A, calculated by weight percentage, include: 10-40% alkyd resin, 1-15% aldehyde-ketone resin, 10-20% nitrocellulose, 0.1-5% additive, 3-8% cellulose organic acid ester, and the solvent makes up the balance; the raw materials of component B, calculated by weight percentage, The raw materials include: 40-60% solvent, 0.1-2% dehydrating agent, and TDI curing agent to make up the balance; The cellulose organic acid ester includes cellulose acetate butyrate, wherein the cellulose acetate butyrate has an acetyl content of 10-20 wt % and a glass transition temperature of 125-135° C.; The alkyd resin has a solid content of 70-85 wt % and a hydroxyl value of 120-180 mg KOH / g; The aldehyde-ketone resin has a softening point of 105-150° C., a glass transition temperature of 85-120° C., and a hydroxyl value of 300-400 mgKOH / g.

2. The anti-circular hole sealing primer according to claim 1, characterized in that: The aldehyde-ketone resin has a softening point of 105-120° C., a glass transition temperature of 85-95° C., and a hydroxyl value of 300-340 mg KOH / g.

3. The anti-circular hole sealing primer according to claim 2, characterized in that: The solvent includes at least one of butyl acetate, ethyl acetate, dimethyl carbonate, and propylene glycol methyl ether acetate.

4. The anti-circular hole sealing primer according to claim 3, characterized in that: The weight ratio of the alkyd resin, the aldehyde-ketone resin and the nitrocellulose is (10-30): (6-12): (10-20).

5. The anti-circular hole sealing primer according to claim 4, characterized in that: The auxiliary agent includes at least one of a dispersant, a defoaming agent, and a leveling agent.

6. A method for preparing the anti-circular hole sealing primer according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: adding alkyd resin, aldehyde-ketone resin, nitrocellulose, additives and cellulose organic acid ester into a solvent, mixing and stirring evenly to obtain component A; adding a dehydrating agent and a TDI curing agent into the solvent and stirring evenly to obtain component B; and mixing components A and B to obtain the product.

7. An application of the anti-circular hole sealing primer according to any one of claims 1 to 5, characterized in that: Applicable to solid wood products.

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