A preparation process of lightweight polyurethane model

Abstract

The present invention provides a process for preparing a lightweight polyurethane model, the polyurethane model comprising a polyurethane surface layer, a polyurethane foam inner layer, and a topcoat applied to the outer surface of the polyurethane surface layer; the topcoat formula comprises: an emulsion, a defoamer, a pH regulator, a wetting agent, a dispersant, a leveling agent, a feel agent, a matting agent, a film-forming aid, a thickener, and deionized water. The advantages of the present invention are that the polyurethane model achieves the advantage of being lightweight, and the topcoat is selected from an emulsion A having excellent adhesion when sprayed on the polyurethane model, a wetting agent using an organosilicon wetting agent and an appropriate amount of a fluorocarbon wetting agent, and a matting agent using fumed silica combined with micro-wax powder and a suitable feel agent. Thus, a topcoat having excellent adhesion, excellent scratch resistance, and a good feel can be prepared on the surface of the polyurethane model, meeting the requirements of high-end models.

Description

Technical field

[0001] The invention relates to the technical field of clothing model props, and in particular to a preparation process of a lightweight polyurethane model. [Background Technology]

[0002] Mannequins are props used by clothing stores to showcase clothing. For mid- to high-end clothing stores, mannequins are essential props, playing a crucial role in attracting customers, showcasing clothing, and projecting a high-end image. Traditional mannequin props primarily fall into the following categories: 1. Wooden mannequins, made from sawdust or solid wood; 2. Injection-molded mannequins made from plastic or PE resin. Both types of mannequins are relatively heavy and difficult to move during use.

[0003] Polyurethane, or polyurethane, is a polymer material with a carbamate structure and is a reactive polymer. Polyurethane refers to any polymer containing -NH-CO-O- groups in its backbone. Polyurethane foam offers advantages such as high strength, light weight, and ease of processing and molding, making it widely used in various industries.

[0004] In view of the problems existing in the existing models, this case developed a prop model made of polyurethane foam. In addition, this case analyzed the composition and molding of the polyurethane materials used in the prop model and prepared a topcoat with excellent adhesion on the surface of the polyurethane model based on the problems encountered in the production of polyurethane models. [Summary of the invention]

[0005] The present invention aims to solve the technical problem that the prop models in the prior art are relatively bulky and difficult to move during use, and provides a preparation process for a lightweight polyurethane model.

[0006] The present invention is achieved by providing a preparation process of a lightweight polyurethane model, wherein the polyurethane model comprises a polyurethane surface layer, a polyurethane foaming inner layer, and a topcoat coated on the outer surface of the polyurethane surface layer.

[0007] Furthermore, the polyurethane surface layer is formed by the reaction of polyether polyol and polyisocyanate, and the polyurethane foam inner layer is formed by the reaction of polyether polyol, polyisocyanate, a foaming agent, and a catalyst.

[0008] Furthermore, the catalyst is an organic amine catalyst or an organic metal compound catalyst.

[0009] Furthermore, the formula of the topcoat includes:

[0010]

[0011] Furthermore, the matting agent includes fumed silica and micro wax powder, and the ratio of fumed silica to micro wax powder is 1:1.

[0012] Furthermore, the wetting agent is a mixture of an organosilicon wetting agent and a fluorocarbon wetting agent.

[0013] Furthermore, the topcoat further comprises 3-3.5% of a feel agent; the feel agent is a mixture of a wax emulsion and an organosilicon feel agent.

[0014] Furthermore, the film-forming aid includes a mixture of DPM and DPNB.

[0015] Furthermore, the preparation process of the topcoat comprises the following steps:

[0016] Step 1: First add the emulsion into the dispersion tank, then add the defoamer, pH regulator, wetting agent, dispersant, leveling agent and matting agent in sequence at a speed of 500r / min, then adjust the speed to 2000-2500r / min and disperse at high speed for 30 minutes;

[0017] Step 2: Adjust the speed to 1500r / min, add the mixture of film-forming aid and deionized water, and stir for 10-15 minutes;

[0018] Step 3: Finally, add thickener to adjust to the appropriate viscosity.

[0019] Furthermore, in step 1, a hand feeling agent is added before adding a matting agent, and the order of adding the matting agent is to add fumed silica and micro wax powder in sequence.

[0020] The advantages of the present invention are that it solves the technical problem of existing mannequin props being bulky and difficult to move during use, thereby achieving a lightweight mannequin. The topcoat is an emulsion A with excellent adhesion, which is sprayed onto the polyurethane mannequin. A silicone wetting agent and an appropriate amount of a fluorocarbon wetting agent are used as the wetting agent. A matting agent is fumed silica combined with micro-wax powder, along with a suitable feel agent. This allows the production of a topcoat with excellent adhesion, scratch resistance, and a pleasant feel on the polyurethane mannequin surface, meeting the requirements of high-end mannequins.

Brief Description of the Drawings

[0021] The present invention will be further described below with reference to the accompanying drawings and in combination with the test group.

[0022] Figure 1 This is a schematic diagram of the pinhole-free state after the topcoat is sprayed in Example 1.

[0023] Figure 2 This is a schematic diagram of the pinhole state after the topcoat is sprayed in Example 1.

[0024] Figure 3 This is a spraying effect diagram of the topcoat sprayed on the surface of the polyurethane model in Example 2. [Specific implementation method]

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention for which protection is sought, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] The present invention provides a process for preparing a lightweight polyurethane mannequin. The polyurethane mannequin comprises a polyurethane surface layer, a polyurethane foam inner layer, and a topcoat applied to the outer surface of the polyurethane surface layer. The polyurethane mannequin of the present invention is injection molded using RIM technology. The polyurethane mannequin comprises a relatively dense polyurethane surface layer and a polyurethane foam inner layer. The polyurethane surface layer is formed by the reaction of polyether polyol and polyisocyanate, while the polyurethane foam inner layer is formed by the reaction of polyether polyol, polyisocyanate, a blowing agent, and a catalyst. The prop mannequin prepared using polyurethane material achieves lightweight performance.

[0027] Preparation process of polyurethane foam inner layer: First, polyisocyanate and foaming agent generate polymer and release gas, which is foaming reaction. At the same time, a large amount of heat is generated, which increases the temperature. It can promote the reaction between -NH- structure and polyisocyanate contained in the polyurethane synthesis process to form a three-dimensional network structure, which promotes the rapid gelation of the system.

[0028] Preferably, the foaming agent is a chemical foaming agent, which is used to foam the polyurethane to obtain a larger open porosity. Since the polyurethane foam inner layer is enclosed within the polyurethane surface layer and does not match the surface coating, there is no requirement for open porosity or closed porosity. For environmental protection, economic efficiency, and safety requirements, water is used as the foaming agent for the polyurethane foam inner layer.

[0029] Preferably, the catalyst is an organic amine catalyst or an organometallic compound catalyst. Different catalysts have different catalytic activities for different chemical reactions in polyurethane. The catalytic activity of organic amine catalysts is more "foaming effect" (reaction between isocyanate and water) than "gel effect" (reaction between isocyanate and hydroxyl groups), while the catalytic activity of organometallic compound catalysts is more "gel effect" than "foaming effect".

[0030] During the RIM injection molding process for polyurethane molds, a release agent, typically composed of polyether silicone, must be applied to the mold beforehand. This release agent allows the mold to be easily separated from the mold after molding, but residual release agent may remain on the mold surface, hindering its surface coating. Therefore, during the surface coating process, the mold surface must be cleaned and sandblasted to remove any residual release agent. The mold coating process includes the following steps: cleaning → sandblasting → putty leveling → sandblasting → primer → sandblasting → topcoat.

[0031] Preferably, the topcoat comprises: 73-77% emulsion, 0.2-0.4% defoamer, 0.1% pH regulator, 0.5-0.6% wetting agent, 0.4-0.6% dispersant, 0.25-0.35% leveling agent, 1.8-2.2% matting agent, 4-6% film-forming aid, 0.9% thickener, and 11.8-17.3% deionized water. The emulsion preferably uses Emulsion A produced by Jiafeng Chemical, whose main component is a modified acrylic polymer, has a curing capacity of 42±1%, and a minimum film-forming temperature (MFT) of 20°C.

[0032] Preferably, the defoaming agent is an organosilicon emulsion, preferably TEGO-825, which has a good defoaming effect and is not prone to oil shrinkage.

[0033] Preferably, the pH regulator is Dow's AMP-95.

[0034] Preferably, the wetting agent is a mixture of 0.5% silicone wetting agent and 0.1% fluorocarbon wetting agent. Fluorocarbon wetting agents have low surface tension, excellent dynamic surface tension, and rapid spreading, but they are expensive. Excessive use of fluorocarbon wetting agents is not recommended, as this can easily cause bubbling during spraying. Silicone wetting agents have excellent static surface tension and moderate rapid spreading, but they are more affordable. Therefore, a combination of 0.1% fluorocarbon wetting agent and 0.5% silicone wetting agent offers excellent cost-effectiveness. The silicone wetting agent is A-8729 from Lanbo New Materials, while the fluorocarbon wetting agent is A-1190.

[0035] Preferably, the dispersant is TEGO-752W produced by Digo, which is a high molecular polymer dispersant with a good dispersing effect on micro wax powder, making the micro wax powder more compatible with the emulsion, making it difficult for the micro wax powder to float to the surface, and thus improving the storage stability of the micro wax powder in the system.

[0036] Preferably, the leveling agent is a polyether-modified silicone, preferably TEGO GLIDE 410, which is a polyether-modified silicone that can quickly balance the surface tension difference of "Bénard cells" during coating and improve the smoothness of the coating.

[0037] Preferably, the matting agent comprises fumed silica and microwax powder, with the ratio of fumed silica to microwax powder being 1:1. The microwax powder is oxidized polyethylene wax powder, composed of regular spherical particles with a narrow particle size distribution and uniform fineness. When added to the system, it can improve the topcoat's anti-sticking and anti-scratch capabilities. Its specific gravity is lighter than water, and when it is not compatible with the emulsion system, it easily floats to the surface and will clump over time. The microwax powder is Evonik's microwax powder P-2026, and the fumed silica is Evonik's fumed silica matting agent P-2021.

[0038] Preferably, the film-forming aid comprises a mixture of DPM and DPNB, with the ratio of DPM to DPNB being 2:3. DPM (dipropylene glycol methyl ether) has excellent film-forming properties but a low volatilization rate, which reduces the early hardness improvement of the coating film. Compared to DPNB (dipropylene glycol butyl ether), DPM has poorer film-forming properties and a fast volatilization rate, which has less impact on the early hardness of the paint film. Therefore, the combination of DPM and DPNB can help the emulsion quickly polymerize and form a film, achieving excellent film-forming properties and rapidly improving early hardness.

[0039] Preferably, the thickener is a mixture of Deqian Chemical's WT-108 and Wanhua Chemical's U-300, with the WT-108 concentration preferably being 0.4% and the U-300 concentration preferably being 0.5%.

[0040] Preferably, the topcoat further comprises 3-3.5% of a feel agent; the feel agent is a mixture of a wax emulsion and a silicone feel agent. The silicone feel agent is A-8714 from Lanbo New Materials. The wax emulsion is A-8711 from Lanbo New Materials.

[0041] Example 1

[0042] This embodiment provides a topcoat preparation process, comprising the following steps:

[0043] Step 1: First add the emulsion into the dispersion tank, then add the defoamer, pH regulator, wetting agent, dispersant, leveling agent and matting agent in sequence at a speed of 500r / min, then adjust the speed to 2000-2500r / min and disperse at high speed for 30 minutes;

[0044] Step 2: Adjust the speed to 1500r / min, add the mixture of film-forming aid and deionized water, and stir for 10-15 minutes;

[0045] Step 3: Finally, add thickener to adjust to the appropriate viscosity.

[0046] Preferably, in step 1, the order of adding the matting agent is to add fumed silica and micro wax powder in sequence.

[0047] The beneficial effects of the topcoat prepared by the topcoat preparation process of this embodiment are further illustrated below through several test groups and comparison groups.

[0048] Experimental group 1

[0049] The preparation process of the topcoat comprises the following steps: first, adding 75% of emulsion A (curing amount of 42±1%, main component of modified acrylic polymer, MFT of 20°C) produced by Jiafeng Chemical into a dispersion tank; then, adding 0.3% of defoamer, 0.1% of pH regulator, 0.5% of organosilicon wetting agent and 0.1% of fluorocarbon wetting agent, 0.5% of dispersant, 0.3% of leveling agent, and 2% of matting agent in sequence at a rotation speed of 500 r / min; then, adjusting the rotation speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then, adjusting the rotation speed to 1500 r / min, adding 5% of film-forming aid and 15.3% of deionized water, and stirring for 10-15 minutes; and finally, adding a thickener to adjust the viscosity to a suitable value. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; and the matting agent is a mixture of 1% fumed silica and 1% micro wax powder.

[0050] Experimental Group 2

[0051] The preparation process of the topcoat comprises the following steps: first, adding 73% of emulsion A (curing amount of 42±1%, main component of modified acrylic polymer, MFT of 20°C) produced by Jiafeng Chemical into a dispersion tank; then, adding 0.3% of defoamer, 0.1% of pH regulator, 0.5% of organosilicon wetting agent and 0.1% of fluorocarbon wetting agent, 0.5% of dispersant, 0.3% of leveling agent, and 2% of matting agent in sequence at a rotation speed of 500 r / min; then, adjusting the rotation speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then, adjusting the rotation speed to 1500 r / min, adding 5% of film-forming aid and 17.3% of deionized water, and stirring for 10-15 minutes; and finally, adding a thickener to adjust the viscosity to a suitable value. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; and the matting agent is a mixture of 1% fumed silica and 1% micro wax powder.

[0052] Experimental group three

[0053] The preparation process of the topcoat comprises the following steps: first, adding 77% of emulsion A (curing amount of 42±1%, main component of modified acrylic polymer, MFT of 20°C) produced by Jiafeng Chemical into a dispersion tank; then, adding 0.3% of defoamer, 0.1% of pH regulator, 0.5% of organosilicon wetting agent and 0.1% of fluorocarbon wetting agent, 0.5% of dispersant, 0.3% of leveling agent, and 2% of matting agent in sequence at a rotation speed of 500 r / min; then, adjusting the rotation speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then, adjusting the rotation speed to 1500 r / min, adding 5% of film-forming aid and 13.3% of deionized water, and stirring for 10-15 minutes; and finally, adding a thickener to adjust the viscosity to a suitable value. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; and the matting agent is a mixture of 1% fumed silica and 1% micro wax powder.

[0054] Comparison group 1

[0055] The preparation process of the topcoat comprises the following steps: first, adding 75% of emulsion B (curing amount of 42±1%, main component of modified acrylic polymer, MFT of 30°C) produced by Jiafeng Chemical into a dispersion tank; then, adding 0.3% of defoamer, 0.1% of pH regulator, 0.5% of organosilicon wetting agent and 0.1% of fluorocarbon wetting agent, 0.5% of dispersant, 0.3% of leveling agent, and 2% of matting agent in sequence at a rotation speed of 500 r / min; then, adjusting the rotation speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then, adjusting the rotation speed to 1500 r / min, adding 5% of film-forming aid and 15.3% of deionized water, and stirring for 10-15 minutes; and finally, adding a thickener to adjust the viscosity to a suitable value. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; and the matting agent is a mixture of 1% fumed silica and 1% micro wax powder.

[0056] Comparison group 2

[0057] The preparation process of the topcoat includes the following steps: first, adding 75% of Emulsion C produced by Wanhua Chemical (with a curing amount of 42±1%, a main component of polyurethane-modified acrylic polymer, and an MFT of 25°C) into a dispersion tank; then, at a speed of 500 r / min, adding 0.3% of a defoamer, 0.1% of a pH regulator, 0.5% of a silicone wetting agent, 0.1% of a fluorocarbon wetting agent, 0.5% of a dispersant, 0.3% of a leveling agent, and 2% of a matting agent in sequence; then, adjusting the speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then, adjusting the speed to 1500 r / min, adding 5% of a film-forming aid and 15.3% of deionized water, and stirring for 10-15 minutes; and finally, adding a thickener to adjust the viscosity to a suitable value. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; and the matting agent is a mixture of 1% fumed silica and 1% micro wax powder.

[0058] Comparison group 3

[0059] The preparation process of the topcoat includes the following steps: first, adding 75% of emulsion D produced by Wanhua Chemical (curing amount of 42±1%, main component is modified acrylic polymer, MFT of 30°C) into a dispersion tank; then, at a speed of 500 r / min, adding 0.3% defoamer, 0.1% pH regulator, 0.5% silicone wetting agent and 0.1% fluorocarbon wetting agent, 0.5% dispersant, 0.3% leveling agent, and 2% matting agent in sequence; then, adjusting the speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then adjusting the speed to 1500 r / min, adding 5% film-forming aid and 15.3% deionized water, and stirring for 10-15 minutes; finally, adding a thickener to adjust to a suitable viscosity. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; and the matting agent is a mixture of 1% fumed silica and 1% micro wax powder.

[0060] Comparison group 4

[0061] The preparation process of the topcoat comprises the following steps: first, adding 75% of emulsion A (curing amount of 42±1%, main component of modified acrylic polymer, MFT of 20°C) produced by Jiafeng Chemical into a dispersion tank; then, adding 0.3% of defoamer, 0.1% of pH regulator, 0.6% of organosilicon wetting agent, 0.5% of dispersant, 0.3% of leveling agent, and 2% of matting agent in sequence at a rotation speed of 500 r / min; then, adjusting the rotation speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then, adjusting the rotation speed to 1500 r / min, adding 5% of film-forming aid and 15.3% of deionized water, and stirring for 10-15 minutes; and finally, adding a thickener to adjust the viscosity to a suitable value. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; and the matting agent is a mixture of 1% fumed silica and 1% micro wax powder.

[0062] Comparison group 5

[0063] The preparation process of the topcoat comprises the following steps: first, adding 75% of emulsion A (curing amount of 42±1%, main component of modified acrylic polymer, MFT of 20°C) produced by Jiafeng Chemical into a dispersion tank; then, adding 0.3% of defoamer, 0.1% of pH regulator, 0.3% of organosilicon wetting agent and 0.3% of fluorocarbon wetting agent, 0.5% of dispersant, 0.3% of leveling agent, and 2% of matting agent in sequence at a rotation speed of 500 r / min; then, adjusting the rotation speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then, adjusting the rotation speed to 1500 r / min, adding 5% of film-forming aid and 15.3% of deionized water, and stirring for 10-15 minutes; and finally, adding a thickener to adjust the viscosity to a suitable value. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; and the matting agent is a mixture of 1% fumed silica and 1% micro wax powder.

[0064] Table 1 Specific ingredients of experimental groups 1 to 3 and control groups 1 to 5

[0065]

[0066]

[0067] The prepared topcoat was sprayed on the outer surface of the polyurethane model, and the wettability, adhesion, scratch resistance and storage stability of various topcoats on the model surface were observed and compared.

[0068] Table 2 Comparison of test results of each experimental group and control group

[0069]

[0070] (Note: Adhesion: 1 means the best, 5 means the worst)

[0071] According to the results in Table 2, the topcoat obtained by the preparation process of this embodiment, the topcoat using emulsion A has good adhesion to the surface of the polyurethane model, excellent scratch resistance, stable storage state without wax floating, good wettability, and no pinholes on the paint surface (as can be seen from the comparison of test groups 1 to 3 and comparison groups 1 to 3). And according to the attached Figure 1 and 2 As shown, attached Figure 1 The spraying results of test groups 1 to 3 are shown. There are no pinholes on the surface. It can be seen that the fluorocarbon wetting agent has a good effect on improving the spreading of difficult-to-wet substrates. Figure 2 To compare the spraying effects of groups four and five, pinholes appeared on the surface, indicating that the dosage of fluorocarbon wetting agent should not be too high.

[0072] Pinholes appearing during spraying are not only related to the surface tension of the substrate, but also to the surface tension of the topcoat and whether the wetting agent used can spread quickly on the substrate. When spraying, when large droplets are atomized into small droplets, the surface area of the liquid increases, and the surface tension of the liquid has a dynamic equilibrium process. The shorter the time it takes for the wetting agent to move from the micelles formed inside the droplets to the liquid surface, the faster the dynamic surface equilibrium is, and the better the paint spreads on the substrate. If it takes too much time, the dynamic surface equilibrium is too slow, and it is easy to cause adhesion. Figure 2 The phenomenon in .

[0073] Therefore, this embodiment selects emulsion A with excellent adhesion to polyurethane substrates, uses a conventional silicone wetting agent and an appropriate amount of fluorocarbon wetting agent as the wetting agent, and uses fumed silica combined with micro-wax powder as the matting agent. This can prepare a topcoat with excellent adhesion, excellent scratch resistance, and good wettability on the model surface, which can meet the requirements of high-end models.

[0074] Example 2

[0075] This example further tests the scratch resistance and paint feel of the topcoat based on the first test group. This example provides another topcoat preparation process, including the following steps:

[0076] Step 1: First add the emulsion into the dispersion tank, then add the defoamer, pH regulator, wetting agent, dispersant, leveling agent, feel agent and matting agent in sequence at a speed of 500r / min, then adjust the speed to 2000-2500r / min and disperse at high speed for 30 minutes;

[0077] Step 2: Adjust the speed to 1500r / min, add the mixture of film-forming aid and deionized water, and stir for 10-15 minutes;

[0078] Step 3: Finally, add thickener to adjust to the appropriate viscosity.

[0079] Preferably, in step 1, the order of adding the matting agent is to add fumed silica and micro wax powder in sequence.

[0080] The beneficial effects of the topcoat prepared by the topcoat preparation process of Example 2 are further illustrated below through experimental group 4 and several comparative groups.

[0081] Experimental group 4

[0082] The preparation process of the topcoat comprises the following steps: first, adding 75% of emulsion A (curing amount of 42±1%, main component of modified acrylic polymer, MFT of 20°C) produced by Jiafeng Chemical into a dispersion tank; then, at a rotation speed of 500 r / min, sequentially adding 0.3% of defoamer, 0.1% of pH regulator, 0.5% of organosilicon wetting agent and 0.1% of fluorocarbon wetting agent, 0.5% of dispersant, 0.3% of leveling agent, 3.5% of hand feeling agent, and 2% of matting agent; then, adjusting the rotation speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then, adjusting the rotation speed to 1500 r / min, adding 5% of film-forming aid and 11.8% of deionized water, and stirring for 10-15 minutes; and finally, adding a thickener to adjust the viscosity to a suitable value. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; the matting agent is 1% fumed silica and 1% micro wax powder, and the feeling agent is 3% wax emulsion A-8711 and 0.5% silicone feeling agent A-8714.

[0083] Comparison group 6

[0084] The preparation process of the topcoat comprises the following steps: first, adding 75% of emulsion A (curing amount of 42±1%, main component of modified acrylic polymer, MFT of 20°C) produced by Jiafeng Chemical into a dispersion tank; then, at a rotation speed of 500 r / min, sequentially adding 0.3% of defoamer, 0.1% of pH regulator, 0.5% of organosilicon wetting agent and 0.1% of fluorocarbon wetting agent, 0.5% of dispersant, 0.3% of leveling agent, 3.5% of hand feeling agent, and 2% of matting agent; then, adjusting the rotation speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then, adjusting the rotation speed to 1500 r / min, adding 5% of film-forming aid and 11.8% of deionized water, and stirring for 10-15 minutes; and finally, adding a thickener to adjust the viscosity to a suitable value. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; the matting agent is 1% fumed silica and 1% micro wax powder, and the feeling agent is 3% wax emulsion A-8711 and 0.5% macromolecular silicone feeling agent DC-51.

[0085] Comparison group seven

[0086] The preparation process of the topcoat comprises the following steps: first, adding 75% of emulsion A (curing amount of 42±1%, main component of modified acrylic polymer, MFT of 20°C) produced by Jiafeng Chemical into a dispersion tank; then, at a rotation speed of 500 r / min, sequentially adding 0.3% of defoamer, 0.1% of pH regulator, 0.5% of organosilicon wetting agent and 0.1% of fluorocarbon wetting agent, 0.5% of dispersant, 0.3% of leveling agent, 3.5% of hand feeling agent, and 2% of matting agent; then, adjusting the rotation speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then, adjusting the rotation speed to 1500 r / min, adding 5% of film-forming aid and 12.3% of deionized water, and stirring for 10-15 minutes; and finally, adding a thickener to adjust the viscosity to a suitable value. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; the matting agent is 1% fumed silica and 1% micro wax powder; the hand feeling agent is 3% wax emulsion A-8711.

[0087] Comparison Group 8

[0088] The preparation process of the topcoat comprises the following steps: first, adding 75% of emulsion A (curing amount of 42±1%, main component of modified acrylic polymer, MFT of 20°C) produced by Jiafeng Chemical into a dispersion tank; then, at a rotation speed of 500 r / min, sequentially adding 0.3% of defoamer, 0.1% of pH regulator, 0.5% of organosilicon wetting agent and 0.1% of fluorocarbon wetting agent, 0.5% of dispersant, 0.3% of leveling agent, 3.5% of hand feeling agent, and 2% of matting agent; then, adjusting the rotation speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then, adjusting the rotation speed to 1500 r / min, adding 5% of film-forming aid and 11.8% of deionized water, and stirring for 10-15 minutes; and finally, adding a thickener to adjust the viscosity to a suitable value. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; the matting agent is 2% fumed silica, and the feeling agent is 3% wax emulsion A-8711 and 0.5% silicone feeling agent A-8714.

[0089] Comparison group nine

[0090] The preparation process of the topcoat comprises the following steps: first, adding 75% of emulsion A (curing amount of 42±1%, main component of modified acrylic polymer, MFT of 20°C) produced by Jiafeng Chemical into a dispersion tank; then, at a rotation speed of 500 r / min, sequentially adding 0.3% of defoamer, 0.1% of pH regulator, 0.5% of organosilicon wetting agent and 0.1% of fluorocarbon wetting agent, 0.5% of dispersant, 0.3% of leveling agent, 3.5% of hand feeling agent, and 2% of matting agent; then, adjusting the rotation speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then, adjusting the rotation speed to 1500 r / min, adding 5% of film-forming aid and 11.8% of deionized water, and stirring for 10-15 minutes; and finally, adding a thickener to adjust the viscosity to a suitable value. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; the matting agent is 2% fumed silica, and the feeling agent is 3% wax emulsion A-8711 and 0.5% macromolecular silicone feeling agent DC-51.

[0091] Comparison group 10

[0092] The preparation process of the topcoat comprises the following steps: first, adding 75% of emulsion A (curing amount of 42±1%, main component of modified acrylic polymer, MFT of 20°C) produced by Jiafeng Chemical into a dispersion tank; then, at a rotation speed of 500 r / min, sequentially adding 0.3% of defoamer, 0.1% of pH regulator, 0.5% of organosilicon wetting agent and 0.1% of fluorocarbon wetting agent, 0.5% of dispersant, 0.3% of leveling agent, 3.5% of hand feeling agent, and 2% of matting agent; then, adjusting the rotation speed to 2000-2500 r / min and dispersing at high speed for 30 minutes; then, adjusting the rotation speed to 1500 r / min, adding 5% of film-forming aid and 11.8% of deionized water, and stirring for 10-15 minutes; and finally, adding a thickener to adjust the viscosity to a suitable value. The film-forming aid includes 2% DPM and 3% DPNB; the thickener includes 0.4% thickener WT-108 and 0.5% thickener U-300; the matting agent is 2% fumed silica, and the hand feeling agent is 3% wax emulsion A-8711.

[0093] Table 3 Specific ingredients of experimental group 4 and control groups 6 to 10

[0094]

[0095]

[0096] The topcoats prepared in the above-mentioned test groups and control groups were sprayed on the outer surface of a polyurethane model, and the scratch resistance and feel of the various topcoats on the model surface were observed and compared.

[0097] Table 4 Scratch resistance and feel of the paint surface

[0098] Group Scratch resistance and feel of the paint surface Experimental group 4 The paint film is not broken, there are bright marks, and it feels good Comparison group 6 The sprayed oil-shrink paint film is not broken, has bright marks, and feels good Comparison group seven The paint film is not broken, there are bright marks, and the feel is average Comparison Group 8 The paint film is scratched, which is much lighter than the control group, and feels good. Comparison group nine The scratches on the oil-shrink paint film are much smaller than those in the control group, and the hand feeling is good. Comparison group 10 Paint film scratched

[0099] The experimental results in Table 4 show that a topcoat matting system using micro-wax powder and fumed silica exhibits superior scratch resistance compared to fumed silica alone. Wax emulsions are less effective than micro-wax powder in improving scratch resistance (as can be seen by comparing groups 7 and 10). The macromolecular silicone feel agent DC-51 also has some improvement in scratch resistance, but it primarily focuses on improving the feel and can easily cause oil shrinkage if not properly added (as can be seen by comparing groups 6 and 9). Silicone feel agent A-8714, a relatively compatible silicone additive, also focuses on improving the feel of the coating and has some effect on improving scratch resistance.

[0100] Therefore, the topcoat of this embodiment is selected from emulsion A with excellent adhesion sprayed on the polyurethane model, the wetting agent uses a conventional silicone wetting agent and an appropriate amount of fluorocarbon wetting agent, the matting agent uses fumed silica with micro wax powder, and is combined with a suitable feel agent. A topcoat with excellent adhesion, excellent scratch resistance and good feel on the surface of the polyurethane model can be prepared, which can meet the requirements of high-end models.

[0101] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the specific test groups described are merely illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A process for preparing a lightweight polyurethane model, characterized in that: The polyurethane model comprises a polyurethane surface layer, a polyurethane foaming inner layer, and a topcoat applied to the outer surface of the polyurethane surface layer; The topcoat formula includes: 75±2% emulsion, 0.3±0.1% defoaming agent, 0.1% pH regulator, 0.5-0.6% wetting agent, 0.5±0.1% dispersant, 0.3±0.05% leveling agent, 2±0.2% matting agent, 5±1% film-forming aid, 0.9% thickener, and 11.8-17.3% deionized water; the emulsion adopts emulsion A produced by Jiafeng Chemical, the main component of emulsion A is modified acrylic polymer, the curing amount is 42±1%, and the minimum film-forming temperature is 20°C; the matting agent includes fumed silica and micro wax powder, and the ratio of the fumed silica to micro wax powder is 1:1; the wetting agent is a mixture of 0.5% silicone wetting agent and 0.1% fluorocarbon wetting agent.

2. The process for preparing a lightweight polyurethane model according to claim 1, wherein: The polyurethane surface layer is formed by the reaction of polyether polyol and polyisocyanate, and the polyurethane foam inner layer is formed by the reaction of polyether polyol, polyisocyanate, a foaming agent and a catalyst.

3. The process for preparing a lightweight polyurethane model according to claim 2, wherein: The catalyst is an organic amine catalyst or an organic metal compound catalyst.

4. The process for preparing a lightweight polyurethane model according to claim 1, wherein: The topcoat further comprises 3-3.5% of a feel agent; the feel agent is a mixture of a wax emulsion and an organosilicon feel agent.

5. The process for preparing a lightweight polyurethane model according to claim 1, wherein: The film-forming aid includes a mixture of DPM and DPNB.

6. The process for preparing a lightweight polyurethane mold according to any one of claims 1 to 5, wherein: The preparation process of the topcoat comprises the following steps: Step 1: First add the emulsion into the dispersion tank, then add the defoamer, pH regulator, wetting agent, dispersant, leveling agent and matting agent in sequence at a speed of 500r / min, then adjust the speed to 2000-2500r / min and disperse at high speed for 30 minutes; Step 2: Adjust the speed to 1500r / min, add the mixture of film-forming aid and deionized water, and stir for 10-15 minutes; Step 3: Finally, add thickener to adjust to the appropriate viscosity.

7. The process for preparing a lightweight polyurethane mold according to claim 6, wherein: In step 1, a hand feeling agent is added before adding a matting agent, and the order of adding the matting agent is to add fumed silica and micro wax powder in sequence.

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