Hand brushing and spraying dual-purpose odorless anti-yellowing transparent polyurethane primer suitable for various base materials and preparation method of hand brushing and spraying dual-purpose odorless anti-yellowing transparent polyurethane primer

Abstract

The invention discloses a hand brushing and spraying dual-purpose odorless anti-yellowing transparent polyurethane primer suitable for various base materials and a preparation method thereof. The primer mainly comprises a component A, a component B and a component C, the component A is mainly prepared from odorless coconut oil alkyd resin, zinc stearate, a defoaming agent, a flatting agent, an anti-settling agent, functional resin and an organic solvent; the component B is mainly prepared from an HDI (hexamethylene diisocyanate) tripolymer, a TDI (toluene diisocynate) tripolymer, a dehydrating solvent and a dehydrating agent; the component C is mainly prepared from dimethyl carbonate, n-butyl acetate and propylene glycol methyl ether acetate; the anti-settling agent is a mixed solution of polyamide wax slurry 6900-20X and n-butyl acetate, and the mass concentration of the polyamide wax slurry 6900-20X in the mixed solution is 40%; the functional resin is a mixed solution of cellulose acetate butyrate CAB-381-0.5 and n-butyl acetate, and the mass concentration of the cellulose acetate butyrate CAB-381-0.5 in the mixed solution is 20%. The odorless yellowing-resistant transparent polyurethane primer has the advantages of no blistering, no prickly heat, suitability for various base materials, dual purposes of hand brushing and spraying, and the like.

Description

Technical Field

[0001] This application relates to a transparent polyurethane primer, specifically a non-foaming, non-scalding, dual-purpose (brush and spray) odorless, yellowing-resistant transparent polyurethane primer suitable for various substrates, applicable to the furniture and wood products manufacturing industry. Background Technology

[0002] In the field of high-end wood product coating, polyurethane (PU) clear primer is a key coating for protecting and decorating wood veneers (such as stained wood veneers and engineered wood veneers). However, existing technologies suffer from the following significant bottlenecks:

[0003] First, prominent defects include air bubbles and pinholes: air in the wood pores and mechanical bubbles from hand brushing cause air bubbles and pinholes (prickly heat) in the paint film, which is particularly serious in the "wet-on-wet" process and in porous, high-moisture-content dyed / engineered wood veneers.

[0004] Second, the construction methods are not universally applicable: (1) The hand-brushing process requires the paint to have strong defoaming properties, but excessively strong defoaming properties make it easy for the paint to run during spraying; the spraying process has moderate defoaming properties, and the spraying is defect-free, but moderate defoaming properties make it difficult to eliminate mechanical bubbles and duct bubbles during hand-brushing, thus creating a contradiction between the two construction methods and making them incompatible. (2) Hand-brushing requires the paint to have high thixotropy to prevent sagging, while spraying requires low viscosity to facilitate atomization, creating a contradiction in the rheological requirements of the two construction methods. The above problems result in the limited functionality of market products, requiring users to have two types of paint, increasing costs and complexity.

[0005] Third, it is difficult to balance environmental protection, yellowing resistance and performance: traditional aromatic polyurethane systems are prone to yellowing, which affects the appearance of light-colored materials; at the same time, some dry films are often accompanied by irritating odors, making it difficult to meet increasingly stringent environmental protection and health requirements.

[0006] Therefore, developing a high-performance, general-purpose, odorless, yellowing-resistant, transparent polyurethane primer that can systematically solve the above problems has significant technical value and market prospects. Summary of the Invention

[0007] In view of this, this application provides a non-foaming, non-scalding, dual-purpose (hand brush and spray) odorless, yellowing-resistant transparent polyurethane primer suitable for various substrates, and its preparation method.

[0008] To achieve the above objectives, this application employs the following technical solution:

[0009] A dual-purpose (hand brush and spray) odor-free, yellowing-resistant, transparent polyurethane primer, mainly composed of component A, component B, and component C;

[0010] Component A is mainly prepared from the following raw materials in the following weight ratios:

[0011] 60-75 parts of cleansing coconut oil alkyd resin

[0012] 3-6 parts zinc stearate

[0013] Defoamer 0.3-1 part,

[0014] Leveling agent 0.3-1 part,

[0015] 2-5 parts anti-settling agent

[0016] 3-5 parts of functional resin,

[0017] 10-25 parts organic solvent;

[0018] Component B is mainly prepared from the following raw materials in the following weight ratios:

[0019] 25-35 parts of HDI trimer

[0020] 20-35 parts of TDI trimer

[0021] 30-40 parts of dehydrating solvent

[0022] Dehydrating agent 0.2-1 part;

[0023] Component C is mainly prepared from the following raw materials in the following weight ratios:

[0024] 20-35 parts of dimethyl carbonate

[0025] 35-55 parts of n-butyl acetate

[0026] 15-25 parts of propylene glycol methyl ether acetate;

[0027] The anti-settling agent is a mixture of polyamide wax paste 6900-20X and n-butyl acetate, wherein the mass concentration of polyamide wax paste 6900-20X in the mixture is 40%.

[0028] The functional resin is a mixture of cellulose acetate butyrate CAB-381-0.5 and n-butyl acetate, wherein the mass concentration of cellulose acetate butyrate CAB-381-0.5 in the mixture is 20%.

[0029] The organic solvent is a mixture of propylene glycol methyl ether acetate, n-butyl acetate and dimethyl carbonate in any proportion;

[0030] The defoamer is a modified siloxane-type defoamer or a non-silicone defoamer, preferably a non-silicone defoamer;

[0031] When using, components A, B, and C are mixed in a weight ratio of 1:0.5:0.2-0.4.

[0032] The core of this invention lies in constructing a "triple synergistic system," the specific principles of which are as follows:

[0033] 1. Dynamic Intelligent Rheological Control System: By compounding a self-ground anti-settling agent mixture containing 40% polyamide wax slurry 6900-20X and a functional resin mixture containing 20% ​​cellulose acetate butyrate CAB-381-0.5, the coating acquires "intelligent" shear thinning and delayed viscosity recovery characteristics. The polyamide wax forms a three-dimensional hydrogen bond network, providing macroscopic thixotropy, while CAB provides good solvent release and alignment effects. Together, they achieve rapid response and precise control of shear force.

[0034] 2. Multi-level synergistic defoaming and degassing system: Construct a comprehensive defense mechanism that runs through the entire process of coating film formation, and adopt graded defense: (1) Primary defense (wetting and replacement): Use a gradient volatile solvent system (containing high-boiling-point solvent propylene glycol methyl ether acetate) to gently replace the air in the wood pores and reduce the physical coating gas source; (2) Secondary defense (bubble breaking and escape): Precisely control the surface drying speed of the paint film to reserve a channel for the escape of bubbles; and use defoamer in combination with leveling agent to promote the rupture of residual bubbles without causing shrinkage pores, effectively solving the problem of "wet touching wet" prickly heat.

[0035] 3. Stable and long-lasting anti-yellowing and odor-neutralizing system: (1) Anti-yellowing principle: Aliphatic isocyanate (i.e. component B) and structurally stable anti-yellowing hydroxyl resin (odor-neutralizing coconut oil alkyd resin) are used as base materials to control the yellowing from the source; (2) Odor-neutralizing and environmentally friendly principle: A composite system with propylene glycol methyl ether acetate (PMA) as the main low-odor "green solvent" is constructed, and high-odor solvents such as toluene, xylene, and ketones are eliminated; and resins with low free monomer content (i.e. odor-neutralizing coconut oil alkyd resin) and curing agents (i.e. component B) are used to reduce irritating odors and VOCs release from the source.

[0036] This invention utilizes a combination of a odor-neutralizing coconut oil ester, a preferred functional additive, and a yellowing-resistant cyanate curing agent, formulated with preferred components and dosage ratios. With the synergistic effect of other preferred components and dosage ratios in the system, it has the advantages of not causing bubbling or prickly heat when applied by hand or by spraying.

[0037] Preferably, component A is mainly prepared from the following raw materials in the following weight ratios:

[0038] 65-75 parts of cleansing coconut oil alkyd resin

[0039] 6 parts zinc stearate

[0040] Defoamer 0.5-0.8 parts,

[0041] 0.5 parts leveling agent,

[0042] 2-5 parts anti-settling agent

[0043] 3-4 parts of functional resin,

[0044] Organic solvent 13-22.7 parts,

[0045] Component B is mainly prepared from the following raw materials in the following weight ratios:

[0046] 35 parts of HDI trimer

[0047] 30 parts of TDI trimer

[0048] 34.7 parts of dehydrating solvent,

[0049] 0.3 parts dehydrating agent;

[0050] Component C is mainly prepared from the following raw materials in the following weight ratios:

[0051] 30 parts dimethyl carbonate

[0052] 50 parts of n-butyl acetate

[0053] 20 parts of propylene glycol methyl ether acetate;

[0054] When using, components A, B, and C are mixed in a weight ratio of 1:0.5:0.3.

[0055] Preferably, the modified siloxane defoamer is BYK066N, and the non-silicone defoamer is BYK052, Asahi Kasei OX880, Huaxia HX2300, Sanhua AC-300, Hemings 3500, Jintuan 712N, or BASF EFKA2020. The non-silicone defoamer is preferably Asahi Kasei OX880 or Sanhua AC-300.

[0056] The leveling agent is Gold Group 1695, Huaxia HX3130, BASF EFKA-3239, Chongyao 3369, Zhihui 3600B, Hemings 495, BYK 358N, BYK 354, or BASF EFKA 3777; more preferably, the leveling agent is Gold Group 1695 or Hemings 495.

[0057] The odor-neutralizing coconut oil alkyd resin is Fangxin FX-3070, Changxing 33012, Changxing 33089 or Tuopu 3030; the key parameters of Fangxin FX-3070 are as follows: solids content 70±2%, viscosity 40000-60000cps / 25℃, hydroxyl value 145±10.

[0058] The zinc stearate is either Hanwei zinc stearate TV-A or Jingchen zinc stearate H630F, with zinc stearate used as a functional powder.

[0059] The dehydrating solvent is polyurethane-grade n-butyl acetate;

[0060] The dehydrating agent is Samsung Chemical's FL-180;

[0061] The HDI trimer is Wanhua HI-100, and the TDI trimer is Wanhua TT-350B.

[0062] The preferred proportions of solvent, other functional additives, and anti-settling agents in the system of this invention determine the viscosity of the odor-free, yellowing-resistant, transparent polyurethane primer, ensuring its good workability.

[0063] The present invention also provides a method for preparing the above-mentioned odor-free, yellowing-resistant, transparent polyurethane primer, comprising the following steps:

[0064] (1) Preparation of component A: Add the odor-neutralizing coconut oil alkyd resin, defoamer, leveling agent, anti-settling agent and 3 parts of organic solvent while the machine is stopped. Then start the mixer and adjust the stirring speed to 800-1000 rpm. Disperse for 10-15 min until uniform. Then add zinc stearate and disperse at high speed of 1300-1500 rpm for 15-20 min until uniform until the fineness is ≤45μm. Then add the functional resin and the remaining organic solvent to obtain component A.

[0065] (2) Preparation of component B: HDI trimer, TDI trimer, dehydrating solvent and dehydrating agent are put into the material tank, the stirrer is started, and the mixture is dispersed at high speed of 1300-1500 rpm for 15-20 min to obtain the component B;

[0066] (3) Preparation of component C: Dimethyl carbonate, n-butyl acetate and propylene glycol methyl ether acetate are added to the feed tank, the stirrer is started, and the mixture is dispersed at high speed of 800-1000 rpm for 10-15 min to obtain component C.

[0067] Specifically, the preparation method of the odor-free, yellowing-resistant, transparent polyurethane primer further includes step (4): when using it, mix component A, component B and component C evenly in a weight ratio of 1:0.5:0.2-0.4 to obtain the odor-free, yellowing-resistant, transparent polyurethane primer.

[0068] The preparation method of the odor-free, yellowing-resistant, transparent polyurethane primer is simple and easy to operate.

[0069] As can be seen from the above technical solution, this application has at least the following advantages and positive effects:

[0070] (1) This invention uses additives such as a mixture of anti-settling agent containing 40% polyamide wax paste 6900-20X and a functional resin mixture containing 20% ​​cellulose acetate butyrate CAB-381-0.5 to enable the coating to have "intelligent" shear thinning and viscosity delayed recovery characteristics. The polyamide wax forms a three-dimensional hydrogen bond network to provide macroscopic thixotropy, and CAB provides good solvent release and arrangement effect. The two work together to achieve rapid response and precise recovery control to shear force, balancing the high thixotropy required for hand brushing and the low viscosity required for spraying. This allows the odor-free, yellowing-resistant transparent polyurethane primer of this invention to achieve two uses in one paint, unifying hand brush and spray products, thereby simplifying procurement, warehousing, and construction management, avoiding misuse, and reducing costs and increasing efficiency.

[0071] (2) This invention employs a multi-level synergistic defoaming and degassing system, namely, constructing a graded defense mechanism that runs through the entire coating formation process: Level 1 defense (wetting and displacement): using a gradient evaporation solvent system (containing the high-boiling-point solvent propylene glycol methyl ether acetate) to gently displace air in the wood pores, reducing the physical encapsulation of air sources; Level 2 defense (bubble breaking and escape): precisely controlling the surface drying speed of the paint film to reserve channels for bubble escape; and using defoamers in combination with leveling agents to promote the rupture of residual bubbles without causing pinholes, effectively solving the problem of "wet-on-wet" blemishes. At the same time, this systematic antifoaming overcomes the problems of bubbles and pinholes on high-risk substrates, supports "wet-on-wet" processes, significantly reduces rework and scrap rates, and improves quality stability.

[0072] (3) The present invention uses aliphatic isocyanate (i.e. component B) and structurally stable yellowing hydroxyl resin (i.e. odorless coconut oil alkyd resin) as base materials to achieve yellowing resistance from the source.

[0073] (4) This invention constructs a composite system with propylene glycol methyl ether acetate (PMA) as the main low-odor "green solvent", abandoning high-odor solvents such as toluene, xylene, and ketones, and using resins and curing agents with low free monomer content (i.e. component B) to reduce irritating odor and VOCs release from the source, achieving low odor and low VOCs, while maintaining the excellent physical properties of solvent-based polyurethane, achieving a unity of high performance and environmental protection, and meeting the dual needs of the high-end market for environmental protection and performance.

[0074] (5) The yellowing-resistant transparent polyurethane primer of the present invention has stable performance, which can reduce the over-reliance on workers' experience and provide a material basis for the standardization and reproducibility of coating process. Attached Figure Description

[0075] Figure 1 Test images of the odor-free, yellowing-resistant transparent polyurethane primer applied by brushing and spraying onto various substrates, which are comparative examples of this application.

[0076] Figure 2These are test images of the odor-free, yellowing-resistant, transparent polyurethane primer of Example 3 of this application, applied by brushing and spraying onto various substrates. Detailed Implementation

[0077] The exemplary embodiments of the present invention are described in more detail below. These embodiments are intended to provide a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art. While exemplary embodiments of the present invention are shown, it should be understood that the invention should not be limited to the embodiments set forth herein.

[0078] Example 1

[0079] A dual-purpose, odor-free, yellowing-resistant, transparent polyurethane primer suitable for both brushing and spraying on various substrates, mainly composed of component A, component B, and component C;

[0080] Component A is mainly prepared from the following raw materials in the following weight ratios:

[0081] 65 parts of cleansing coconut oil alkyd resin

[0082] 6 parts zinc stearate

[0083] 0.8 parts of defoamer

[0084] 0.5 parts leveling agent,

[0085] 5 parts anti-settling agent

[0086] 4 parts of functional resin,

[0087] 22.7 parts of organic solvent;

[0088] Component B is mainly prepared from the following raw materials in the following weight ratios:

[0089] 35 parts of HDI trimer

[0090] 30 parts of TDI trimer

[0091] 34.7 parts of dehydrating solvent,

[0092] 0.3 parts dehydrating agent;

[0093] Component C is mainly prepared from the following raw materials in the following weight ratios:

[0094] 30 parts dimethyl carbonate

[0095] 50 parts of n-butyl acetate

[0096] 20 parts of propylene glycol methyl ether acetate.

[0097] Among them, the odor-neutralizing coconut oil alkyd resin is Top 3030; the zinc stearate is Hanwei's zinc stearate TV-A; the defoamer is Asahi Kasei OX880; the leveling agent is Jintuan 1695; the functional resin is a mixture of cellulose acetate butyrate CAB-381-0.5 and n-butyl acetate, wherein the mass concentration of cellulose acetate butyrate CAB-381-0.5 in the mixture is 20% (preparation method: solid cellulose acetate butyrate CAB-381-0.5 is added to n-butyl acetate to prepare a 20% mass concentration cellulose acetate butyrate CAB-381-0.5 solution); the anti-settling agent is polyamide wax paste 6900-20X. The mixture contains a 40% mass concentration of polyamide wax paste 6900-20X (preparation method: grind solid polyamide wax paste 6900-20X and then add butyl acetate to prepare a 40% mass concentration mixture of polyamide wax paste 6900-20X); the organic solvent is a mixture of propylene glycol methyl ether acetate, butyl acetate and dimethyl carbonate in a weight ratio of 2:4:4; the dehydrating solvent is polyurethane grade butyl acetate; the dehydrating agent is Samsung Chemical's FL-180; the HDI trimer is Wanhua HI-100, and the TDI trimer is Wanhua TT-350B.

[0098] The preparation method of the odor-free, yellowing-resistant, transparent polyurethane primer includes the following steps:

[0099] (1) Preparation of component A: Add the odor-neutralizing coconut oil alkyd resin, defoamer, leveling agent, anti-settling agent and 3 parts of organic solvent while the machine is stopped. Then start the mixer and adjust the stirring speed to 800 rpm. Disperse for 15 min until uniform. Then add zinc stearate and disperse at high speed at 1300 rpm for 20 min until uniform until fineness ≤45μm. Then add the functional resin and the remaining organic solvent to obtain component A.

[0100] (2) Preparation of component B: HDI trimer, TDI trimer, dehydrating solvent and dehydrating agent are put into the material tank, the stirrer is started, and the mixture is dispersed at high speed of 1300 rpm for 20 min to obtain component B;

[0101] (3) Preparation of component C: Dimethyl carbonate, n-butyl acetate and propylene glycol methyl ether acetate are added to the feed tank, the stirrer is started, and the mixture is dispersed at high speed of 800 rpm for 15 min to obtain component C.

[0102] The preparation method of the odor-free, yellowing-resistant, transparent polyurethane primer further includes step (4): when using it, the components A, B and C are mixed evenly in a weight ratio of 1:0.5:0.3 to obtain the odor-free, yellowing-resistant, transparent polyurethane primer.

[0103] Example 2

[0104] A dual-purpose, odor-free, yellowing-resistant, transparent polyurethane primer suitable for both brushing and spraying on various substrates, mainly composed of component A, component B, and component C;

[0105] Component A is mainly prepared from the following raw materials in the following weight ratios:

[0106] 70 parts of cleansing coconut oil alkyd resin

[0107] 6 parts zinc stearate

[0108] 0.5 parts of defoamer

[0109] 0.5 parts leveling agent,

[0110] 4 parts anti-settling agent

[0111] 4 parts of functional resin,

[0112] 15 parts organic solvent;

[0113] Component B is mainly prepared from the following raw materials in the following weight ratios:

[0114] 35 parts of HDI trimer

[0115] 30 parts of TDI trimer

[0116] 34.7 parts of dehydrating solvent,

[0117] 0.3 parts dehydrating agent;

[0118] Component C is mainly prepared from the following raw materials in the following weight ratios:

[0119] 30 parts dimethyl carbonate

[0120] 50 parts of n-butyl acetate

[0121] 20 parts of propylene glycol methyl ether acetate.

[0122] Among them, the odor-neutralizing coconut oil alkyd resin is Changxing 33012; the zinc stearate is Jingchen's zinc stearate H630F; the defoamer is Sanhua AC-300; the leveling agent is Jintuan 1695; the functional resin is a mixture of cellulose acetate butyrate CAB-381-0.5 and n-butyl acetate, wherein the mass concentration of cellulose acetate butyrate CAB-381-0.5 in the mixture is 20% (preparation method: solid cellulose acetate butyrate CAB-381-0.5 is added to n-butyl acetate to prepare a 20% mass concentration cellulose acetate butyrate CAB-381-0.5 solution); the anti-settling agent is polyamide wax paste 6900-20. The mixture of X and n-butyl acetate, wherein the mass concentration of polyamide wax paste 6900-20X in the mixture is 40% (preparation method: grinding solid polyamide wax paste 6900-20X and then adding n-butyl acetate to prepare a mixture with a mass concentration of 40% for polyamide wax paste 6900-20X); the organic solvent is a mixture of propylene glycol methyl ether acetate, n-butyl acetate and dimethyl carbonate in a weight ratio of 2:3:5; the dehydrating solvent is polyurethane grade n-butyl acetate; the dehydrating agent is Samsung Chemical's FL-180; the HDI trimer is Wanhua HI-100, and the TDI trimer is Wanhua TT-350B.

[0123] The preparation method of the odor-free, yellowing-resistant, transparent polyurethane primer includes the following steps:

[0124] (1) Preparation of component A: Add the odor-neutralizing coconut oil alkyd resin, defoamer, leveling agent, anti-settling agent and 3 parts of organic solvent while the machine is stopped. Then start the mixer and adjust the stirring speed to 900 rpm. Disperse for 13 min until uniform. Then add zinc stearate and disperse at 1400 rpm for 17 min until uniform until the fineness is ≤45 μm. Then add the functional resin and the remaining organic solvent to obtain component A.

[0125] (2) Preparation of component B: HDI trimer, TDI trimer, dehydrating solvent and dehydrating agent are put into the material tank, the stirrer is started, and the mixture is dispersed at high speed of 1400 rpm for 17 min to obtain component B;

[0126] (3) Preparation of component C: Dimethyl carbonate, n-butyl acetate and propylene glycol methyl ether acetate are added to the feed tank, the stirrer is started, and the mixture is dispersed at high speed of 900 rpm for 13 min to obtain component C.

[0127] The preparation method of the odor-free, yellowing-resistant, transparent polyurethane primer further includes step (4): when using it, the components A, B and C are mixed evenly in a weight ratio of 1:0.5:0.3 to obtain the odor-free, yellowing-resistant, transparent polyurethane primer.

[0128] Example 3

[0129] A dual-purpose, odor-free, yellowing-resistant, transparent polyurethane primer suitable for both brushing and spraying on various substrates, mainly composed of component A, component B, and component C;

[0130] Component A is mainly prepared from the following raw materials in the following weight ratios:

[0131] 75 parts of cleansed coconut oil alkyd resin

[0132] 6 parts zinc stearate

[0133] 0.5 parts of defoamer

[0134] 0.5 parts leveling agent,

[0135] 2 parts anti-settling agent

[0136] 3 parts of functional resin,

[0137] 13 parts organic solvent;

[0138] Component B is mainly prepared from the following raw materials in the following weight ratios:

[0139] 35 parts of HDI trimer

[0140] 30 parts of TDI trimer

[0141] 34.7 parts of dehydrating solvent,

[0142] 0.3 parts dehydrating agent;

[0143] Component C is mainly prepared from the following raw materials in the following weight ratios:

[0144] 30 parts dimethyl carbonate

[0145] 50 parts of n-butyl acetate

[0146] 20 parts of propylene glycol methyl ether acetate.

[0147] Among them, the odor-neutralizing coconut oil alkyd resin is Fangxin FX-3070; the zinc stearate is Hanwei's zinc stearate TV-A; the defoamer is Sanhua AC-300; the leveling agent is Haimings 495; the functional resin is a mixture of cellulose acetate butyrate CAB-381-0.5 and n-butyl acetate, wherein the mass concentration of cellulose acetate butyrate CAB-381-0.5 in the mixture is 20% (preparation method: solid cellulose acetate butyrate CAB-381-0.5 is added to n-butyl acetate to prepare a 20% mass concentration cellulose acetate butyrate CAB-381-0.5 solution); the anti-settling agent is polyamide wax paste 6900-2. The mixture of 0X and n-butyl acetate contains 40% polyamide wax paste 6900-20X by mass concentration (preparation method: solid polyamide wax paste 6900-20X is ground and then n-butyl acetate is added to prepare a mixture with a polyamide wax paste 6900-20X mass concentration of 40%). The organic solvent is a mixture of propylene glycol methyl ether acetate, n-butyl acetate and dimethyl carbonate in a weight ratio of 2:5:3. The dehydrating solvent is polyurethane grade n-butyl acetate. The dehydrating agent is Samsung Chemical's FL-180. The HDI trimer is Wanhua HI-100 and the TDI trimer is Wanhua TT-350B.

[0148] The preparation method of the odor-free, yellowing-resistant, transparent polyurethane primer includes the following steps:

[0149] (1) Preparation of component A: Add the odor-neutralizing coconut oil alkyd resin, defoamer, leveling agent, anti-settling agent and 3 parts of organic solvent while the machine is stopped. Then start the mixer and adjust the stirring speed to 1000 rpm. Disperse for 10 min until uniform. Then add zinc stearate and disperse at high speed at 1500 rpm for 15 min until uniform until the fineness is ≤45μm. Then add the functional resin and the remaining organic solvent to obtain component A.

[0150] (2) Preparation of component B: HDI trimer, TDI trimer, dehydrating solvent and dehydrating agent are put into the material tank, the stirrer is started, and the mixture is dispersed at high speed of 1500 rpm for 15 min to obtain component B;

[0151] (3) Preparation of component C: Dimethyl carbonate, n-butyl acetate and propylene glycol methyl ether acetate are added to the feed tank, the stirrer is started, and the mixture is dispersed at high speed of 1000 rpm for 10 min to obtain component C.

[0152] The preparation method of the odor-free, yellowing-resistant, transparent polyurethane primer further includes step (4): when using it, the components A, B and C are mixed evenly in a weight ratio of 1:0.5:0.3 to obtain the odor-free, yellowing-resistant, transparent polyurethane primer.

[0153] Comparative example: Commercially available conventional yellowing-resistant transparent polyurethane primer coating

[0154] Detection method:

[0155] Odor: Smell

[0156] Non-foaming property: visually assessed

[0157] Non-irritant to prickly heat: Visually assessed

[0158] Polishability: Hand polishing comparison

[0159] The yellowing-resistant transparent polyurethane primers of each embodiment and comparative example were uniformly applied to the substrate by spraying or brushing, and the product performance indicators were tested. The results are shown in Table 1.

[0160] Table 1. Basic performance test results of each embodiment and comparative example.

[0161]

[0162] Note: The more "+" signs in Table 1, the better.

[0163] Figure 1 It is a comparative ratio of primers on various substrates ( Figure 1 In the middle: the substrate in the left picture is ebony, and the substrate in the right picture is bird's eye. 1) The surface is covered by brushing or spraying, showing some bubbles and small prickly heat, and there are some small raised pores in the wood grain. Figure 2 The primer prepared in Example 3 is used on various substrates ( Figure 2 The substrates in the left, middle, and right images are ebony, bird's eye 1, and bird's eye 2, respectively. They are brushed or sprayed and show no bubbles or prickly heat.

[0164] As shown in Table 1, the yellowing-resistant transparent polyurethane primers of each embodiment have better odor, non-foaming, non-prickly heat-reducing properties, and sandability than the comparative example.

[0165] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A dual-purpose (hand brush and spray) clean, yellowing-resistant, transparent polyurethane primer suitable for various substrates, characterized in that: It is mainly composed of component A, component B and component C; Component A is mainly prepared from the following raw materials in the following weight ratios: 60-75 parts of cleansing coconut oil alkyd resin 3-6 parts zinc stearate Defoamer 0.3-1 part, Leveling agent 0.3-1 part, 2-5 parts anti-settling agent 3-5 parts of functional resin, 10-25 parts organic solvent; Component B is mainly prepared from the following raw materials in the following weight ratios: 25-35 parts of HDI trimer 20-35 parts of TDI trimer 30-40 parts of dehydrating solvent Dehydrating agent 0.2-1 part; Component C is mainly prepared from the following raw materials in the following weight ratios: 20-35 parts of dimethyl carbonate 35-55 parts of n-butyl acetate 15-25 parts of propylene glycol methyl ether acetate; The anti-settling agent is a mixture of polyamide wax paste 6900-20X and n-butyl acetate, wherein the mass concentration of polyamide wax paste 6900-20X in the mixture is 40%. The functional resin is a mixture of cellulose acetate butyrate CAB-381-0.5 and n-butyl acetate, wherein the mass concentration of cellulose acetate butyrate CAB-381-0.5 in the mixture is 20%. The organic solvent is a mixture of propylene glycol methyl ether acetate, n-butyl acetate and dimethyl carbonate in any proportion; The defoamer is a modified siloxane-type defoamer or a non-silicone defoamer; When using, components A, B, and C are mixed in a weight ratio of 1:0.5:0.2-0.

4.

2. The dual-purpose (hand brush and spray) odor-free, yellowing-resistant, transparent polyurethane primer according to claim 1, characterized in that: The modified siloxane defoamer is BYK066N; the non-silicone defoamer is BYK052, Asahi Kasei OX880, Huaxia HX2300, Sanhua AC-300, Hemings 3500, Jintuan 712N or BASF EFKA2020. The leveling agent is Jintuan 1695, Huaxia HX3130, BASF EFKA-3239, Chongyao 3369, Zhihui 3600B, Hemings 495, BYK 358N, BYK 354 or BASF EFKA 3777. The odor-neutralizing coconut oil alkyd resin is Fangxin FX-3070, Changxing 33012, Changxing 33089 or Top 3030; The zinc stearate is either Hanwei zinc stearate TV-A or Jingchen zinc stearate H630F; The dehydrating solvent is polyurethane-grade n-butyl acetate; The dehydrating agent is Samsung Chemical's FL-180; The HDI trimer is Wanhua HI-100, and the TDI trimer is Wanhua TT-350B.

3. The method for preparing the odor-free, yellowing-resistant, transparent polyurethane primer according to any one of claims 1-2, characterized in that: Includes the following steps: (1) Preparation of component A: Add the odor-neutralizing coconut oil alkyd resin, defoamer, leveling agent, anti-settling agent and 3 parts of organic solvent while the machine is stopped. Then start the mixer and adjust the stirring speed to 800-1000 rpm. Disperse for 10-15 min until uniform. Then add zinc stearate and disperse at high speed of 1300-1500 rpm for 15-20 min until uniform until the fineness is ≤45μm. Then add the functional resin and the remaining organic solvent to obtain component A. (2) Preparation of component B: HDI trimer, TDI trimer, dehydrating solvent and dehydrating agent are put into the material tank, the stirrer is started, and the mixture is dispersed at high speed of 1300-1500 rpm for 15-20 min to obtain the component B; (3) Preparation of component C: Dimethyl carbonate, n-butyl acetate and propylene glycol methyl ether acetate are added to the feed tank, the stirrer is started, and the mixture is dispersed at high speed of 800-1000 rpm for 10-15 min to obtain component C.

4. The preparation method of the odor-free, yellowing-resistant, transparent polyurethane primer according to claim 3, characterized in that: It also includes step (4): When using, mix components A, B and C evenly in a weight ratio of 1:0.5:0.2-0.4 to obtain the odor-free, yellowing-resistant transparent polyurethane primer.

Images