Special water-based white protective paint for POF (Polyolefin Fiber) heat shrink film as well as preparation method and application of special water-based white protective paint

Abstract

The invention relates to the technical field of water-based paint, in particular to water-based white protective paint special for a POF heat shrinkage film and a preparation method and application of the water-based white protective paint. The special water-based white protective paint for the POF heat shrink film is prepared from the following raw materials in parts by weight: 50 to 60 parts of functional emulsion, 15 to 25 parts of white slurry, 5 to 10 parts of functional additive and 10 to 15 parts of water, the functional emulsion is a stain-resistant matte emulsion; and the plasticizer is a phthalate compound. The special water-based white surface protective paint for the POF heat shrink film adopts the stain-resistant matte emulsion as a functional emulsion, the stain-resistant matte emulsion, the white slurry, the functional additive and the water are in a specific dosage ratio, and all the raw materials have a synergistic effect, so that migration of a plasticizer in the POF heat shrink film can be inhibited, and the situation that furniture packaged by the POF heat shrink film is not prone to cracking after being subjected to high temperature and high pressure is avoided. And bright marks can appear.

Description

Technical Field

[0001] This invention relates to the field of water-based coatings technology, and in particular to a water-based white protective paint for POF heat shrink film, its preparation method, and its application. Background Technology

[0002] POF heat shrink film, short for biaxially oriented polyolefin shrink film, is a widely used and rapidly developing type of environmentally friendly heat shrink film in the world. It is extensively used for outer packaging and bulk packaging of products in various industries, including food, cosmetics, gifts, pharmaceuticals, stationery, toys, audio-visual products, electronics, wood products, plastic hardware, and daily necessities. Furniture packaged with POF heat shrink film may develop localized shiny marks after high temperature and pressure treatment, affecting the product's appearance. This is especially severe with white paint, where patches of oily shine appear. Preliminary analysis suggests these shiny marks are formed by the transfer of plasticizers from the POF heat shrink film to the coating surface. Summary of the Invention

[0003] This invention provides a water-based white protective paint for POF heat shrink film, its preparation method, and its application, in order to solve the problem of shiny marks appearing on furniture packaged with POF heat shrink film after being subjected to high temperature and high pressure.

[0004] According to a first aspect of the present invention, the present invention provides a water-based white protective paint for POF heat shrink film, comprising the following raw materials in parts by weight: 50-60 parts of functional emulsion, 15-25 parts of white paste, 5-10 parts of functional additives, and 10-15 parts of water; wherein the functional emulsion is a stain-resistant matte emulsion; and the plasticizer is a phthalate compound.

[0005] The water-based white protective paint for POF heat shrink film of this invention uses a stain-resistant matte emulsion as a functional emulsion. It is mixed with white paste, functional additives and water in a specific ratio. The synergistic effect between the raw materials can inhibit the migration of plasticizers (such as phthalate compounds) in POF heat shrink film, and prevent furniture packaged with POF heat shrink film from developing a shiny mark after being subjected to high temperature and high pressure.

[0006] The technical principle behind the ability of stain-resistant matte emulsions to inhibit plasticizer migration in POF heat-shrinkable films can be analyzed from the following aspects: During the film-forming process of stain-resistant matte emulsions, after water evaporation, latex particles are tightly packed together by capillary forces, followed by polymer chain segment diffusion and fusion to form a continuous and dense polymer film. Stain-resistant emulsions typically have small particle sizes and core-shell structures, resulting in very few pores after film formation, significantly reducing the possibility of plasticizer molecules penetrating the coating film through the "dissolution-diffusion" mechanism. Stain-resistant matte emulsions have low surface energy, making it difficult for non-polar plasticizers (such as phthalates) to wet and adsorb. One of the driving forces for plasticizer migration is the hydrogen bonding or van der Waals forces between polar groups (such as ester groups) and the coating surface. Stain-resistant matte emulsions weaken this interaction by shielding polar groups.

[0007] Furthermore, the white paste is formed by mixing titanium dioxide with water, wherein the mass fraction of titanium dioxide is 70-80%.

[0008] Furthermore, phthalate compounds include di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), butyl benzyl phthalate (BBP), diethyl phthalate (DEP), dimethyl phthalate (DMP), di-n-octyl phthalate (DNOP), diisooctyl phthalate (DIOP), and dicyclohexyl phthalate (DCHP), etc.

[0009] Furthermore, the stain-resistant matte emulsion is an anionic emulsion, its components include acrylate polymers, its matteness is 10-15 GU at a 60° incident angle, its stain resistance is <15%, its solid content is 30-40%, its minimum film-forming temperature is ≥0℃, and its pH value is 7.0-9.0.

[0010] The minimum film-forming temperature (MFT) ≥ 0℃ of the stain-resistant matte emulsion indicates that it can form a continuous film at room temperature, while the 30-40% solid content ensures film density. The anionic nature of the emulsion results in a negatively charged surface after film formation, which electrostatically repels the ester groups in the plasticizer molecules. A weakly alkaline environment with a pH of 7.0-9.0 further enhances this repulsion effect. The stain-resistant matte emulsion exhibits a matte finish of 10-15 GU at a 60° incident angle and a stain resistance of <15%, indicating a lower surface energy than conventional emulsions. This characteristic makes it difficult for plasticizers to wet the film surface, increasing the contact angle and thus inhibiting migration.

[0011] Furthermore, the stain-resistant matte emulsion is selected from Showa JH-2630. In this type of stain-resistant matte emulsion, the ester group ratio of the acrylate polymer is more likely to maintain an appropriate difference from the solubility parameters of phthalate compounds, thus ensuring the integrity of the paint film while reducing plasticizer compatibility.

[0012] Furthermore, the plasticizer accounts for 40-60% of the total mass of the POF heat shrink film. By using a specific stain-resistant matte emulsion (such as Showa JH-2630) and precisely proportioned functional additives, a dense, low-surface-energy coating barrier that electrostatically repels plasticizers is formed. This effectively inhibits the migration of phthalate plasticizers, which account for up to 40-60% of the content in the POF heat shrink film, under high temperature and pressure, completely solving the problem of oily gloss marks caused by plasticizer penetration in traditional white paint, and significantly improving the appearance quality of furniture.

[0013] Furthermore, the functional additives include one or more of the following: thickeners, wetting agents, defoamers, film-forming aids, matting materials, leveling agents, and anti-sagging agents.

[0014] The thickener was selected from Hemings 299.

[0015] The wetting agent is selected from Digo 4100.

[0016] The defoamer was selected from Digo's 810.

[0017] The film-forming aid was selected from Dow's DPNB.

[0018] The matting material was selected from Grace's 7000.

[0019] The leveling agent was selected from Digo 410.

[0020] The anti-sagging agent is selected from BYK's RDS.

[0021] Furthermore, the functional additives include 0.1-0.3 parts thickener, 0.4-0.6 parts wetting agent, 0.2-0.4 parts defoamer, 5-7 parts film-forming aid, 0.1-0.3 parts matte material, 0.4-0.6 parts leveling agent, and 1-3 parts anti-sagging aid. By synergistically combining the stain-resistant matte emulsion with precisely proportioned functional additives, a dense and low surface energy coating barrier is formed, effectively blocking the migration path of plasticizers in the POF heat-shrinkable film. This completely eliminates the oily gloss mark on the white topcoat surface under high temperature and high pressure conditions, while maintaining excellent workability and surface smoothness.

[0022] Further, it includes the following raw materials in parts by weight: 50-60 parts functional emulsion, 15-25 parts white paste, 0.1-0.3 parts thickener, 0.4-0.6 parts wetting agent, 0.2-0.4 parts defoamer, 5-7 parts film-forming aid, 0.1-0.3 parts matting material, 0.4-0.6 parts leveling agent, 1-3 parts anti-sagging aid, and 10-15 parts water; The stain-resistant matte emulsion is an anionic emulsion, and its components include acrylate polymers. It has a matte finish of 10-15 GU at a 60° incident angle, stain resistance of <15%, solid content of 30-40℃, minimum film-forming temperature of ≥0℃, and pH value of 7.0-9.0. The plasticizer accounts for 40-60% of the total mass of the POF heat shrink film.

[0023] According to a second aspect of the present invention, the present invention also provides a method for preparing the above-mentioned water-based white protective paint for POF heat shrink film, comprising the following steps: At the first stirring speed, a portion of the thickener and a portion of the water are added to the functional emulsion, and the viscosity is adjusted to 50-60 seconds. Then, the defoamer, wetting agent, film-forming aid, matting material, and white paste are added. At the second stirring speed, the mixture is stirred until the fineness is below 30 microns. Then, the leveling agent, anti-sagging aid, the remaining thickener, and the remaining water are added.

[0024] This invention employs a step-by-step, speed-controlled preparation process. First, at a low speed, a portion of the thickener and water are added to the functional emulsion to adjust the viscosity to 50-60 seconds. Then, at medium to high speed, defoamer, wetting agent, film-forming aid, matting material, and white paste are dispersed sequentially until the fineness is ≤30 μm. Finally, leveling agent, anti-sagging aid, the remaining thickener, and water are added to ensure that all components are uniformly and stably distributed in the stain-resistant matte emulsion, forming a dense, low-surface-energy, and highly smooth coating film. This effectively blocks the migration of plasticizers in the POF heat-shrinkable film, completely eliminates the oily glossy marks of white paint after high temperature and pressure, and simultaneously ensures excellent workability and surface quality.

[0025] Furthermore, the first stirring speed is 300-500 rpm; the second stirring speed is 800-1200 rpm.

[0026] According to a third aspect of the present invention, the present invention also provides the application of the above-mentioned water-based white protective paint for POF heat shrink film or the water-based white protective paint for POF heat shrink film prepared by the above-mentioned preparation method on a workpiece, wherein the water-based white protective paint for POF heat shrink film is coated on the workpiece, and the workpiece is covered with POF heat shrink film.

[0027] After applying the water-based white protective paint for POF heat shrink film of the present invention to the workpiece to be wrapped, and then sealing it with POF heat shrink film containing plasticizer, the migration of plasticizer to the paint film can be completely blocked under subsequent high temperature and high pressure conditions, completely eliminating the oily glossy defects that appear on the surface of traditional white paint, and significantly improving the appearance quality and packaging reliability of various products such as furniture, electronics, and stationery.

[0028] The beneficial effects of this invention are: The present invention provides a water-based white protective paint for POF heat shrink film, which uses a stain-resistant matte emulsion as a functional emulsion. It is mixed with white paste, functional additives and water in a specific ratio. The synergistic effect between the raw materials can inhibit the migration of plasticizers (such as phthalate compounds) in POF heat shrink film, and prevent furniture packaged with POF heat shrink film from developing a shiny mark after being subjected to high temperature and high pressure. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0030] The raw materials used in the following examples and comparative examples are sourced from the following sources: Thickener: Hemings 299; Wetting agent: DIG4100; Defoamer: Digo 810; Film-forming aid: Dow DPNB; White paste: It is formed by mixing titanium dioxide (Dugo 706) with water to form a paste, in which the mass fraction of titanium dioxide is 75%; Matting material: Grace 7000; Leveling agent: Tigo 410; Anti-sagging additive: BYK RDS.

[0031] The stain-resistant matte emulsions used in the following examples are anionic emulsions. Their components may include acrylate polymers, with a matte finish of 10-15 GU at a 60° incident angle, stain resistance <15%, solid content of 30-40℃, minimum film-forming temperature ≥0℃, and pH value of 7.0-9.0. For example, the properties of the stain-resistant matte emulsions are shown in Table 1 below: Table 1 Example 1 This embodiment provides a water-based white protective paint for POF heat shrink film, the raw material composition of which is as follows: Functional emulsion 60kg Thickener 0.2kg 0.5 kg of wetting agent 0.3kg of defoamer Film-forming aid 6kg 20kg of white pulp 0.2kg of matte material 0.5 kg of leveling agent Anti-sagging agent 2kg 10.3 kg of water Among them, the functional emulsion is a water-based stain-resistant matte emulsion (Showa JH-2630).

[0032] This embodiment also provides a method for preparing the water-based white protective coating for POF heat shrink film, including the following steps: Stir the functional emulsion components at a low speed of 400 rpm until homogeneous. Add a portion of the thickener to adjust the viscosity to 50-60 seconds (Iwata No. 2 cup). Add the defoamer, wetting agent, and film-forming aid in sequence, followed by the white paste and matting material. Stir at a high speed of 1000 rpm until there are no oil pockets and the fineness reaches below 30 microns. Add the leveling agent, anti-sagging aid, and the remaining water. Adjust the viscosity to the required level using the remaining thickener.

[0033] Example 2 This embodiment provides a water-based white protective paint for POF heat shrink film, which differs from Embodiment 1 in that its raw material composition is as follows: 50kg of functional emulsion Thickener 0.1kg Wetting agent 0.4kg 0.2kg of defoamer 5kg of film-forming aid 15kg of white pulp 0.1kg of matte material 0.4 kg of leveling agent 1kg of anti-sagging agent 15kg of water.

[0034] Among them, the functional emulsion is a water-based stain-resistant matte emulsion (Showa JH-2630).

[0035] The preparation method of the water-based white protective paint in this embodiment is the same as that in Embodiment 1.

[0036] Example 3 This embodiment provides a water-based white protective paint for POF heat shrink film, which differs from Embodiment 1 in that its raw material composition is as follows: Functional emulsion 55kg Thickener 0.3kg Wetting agent 0.6kg 0.4 kg of defoamer 7kg of film-forming aid 25kg of white pulp 0.3kg of matte material 0.6 kg of leveling agent Anti-sagging agent 3kg 12kg of water.

[0037] Among them, the functional emulsion is a water-based stain-resistant matte emulsion (Showa JH-2630).

[0038] The preparation method of the water-based white protective paint in this embodiment is the same as that in Embodiment 1.

[0039] Comparative Example 1 This comparative example provides a water-based white protective coating, whose raw material composition is as follows: Functional emulsion 60kg Thickener 0.2kg 0.5 kg of wetting agent 0.3kg of defoamer Film-forming aid 6kg 20kg of white pulp Matting material 0.8kg 0.5 kg of leveling agent Anti-sagging agent 2kg 9.7 kg of water.

[0040] Among them, the functional emulsion is an aqueous acrylic emulsion (Zhancheng S7508).

[0041] The preparation method of the water-based white protective paint in this comparative example is the same as that in Example 1.

[0042] Comparative Example 2 This comparative example provides a water-based white protective coating, whose raw material composition is as follows: Functional emulsion 60kg Thickener 0.2kg 0.5 kg of wetting agent 0.3kg of defoamer Film-forming aid 6kg 20kg of white pulp Matting material 0.8kg 0.5 kg of leveling agent Anti-sagging agent 2kg 9.7kg of water Among them, the functional emulsion is an aqueous polyurethane emulsion (Zhancheng S7601).

[0043] The preparation method of the water-based white protective paint in this comparative example is the same as that in Example 1.

[0044] The water-based white protective coatings obtained in Examples 1-3, Comparative Example 1, and Comparative Example 2 were subjected to the following application experiments: Coating method: The product prepared above was sprayed onto a 10cm*10cm glass plate, with a coating amount of 120g / ㎡. The plate was then placed in an oven and dried for 12 hours. The oven temperature was 25℃ and the relative humidity was 50%. Two test plates were prepared for each method.

[0045] Test method: Wrap the test plate with POF heat shrink film (containing 50% phthalate plasticizer), place it face to face in a 70-degree oven, and weigh it down with a 20 kg weight. The plate is then opened and evaluated after three days. The test results are shown in Table 2 below.

[0046] Table 2

[0047] As can be seen from the experimental data in Table 2, the water-based white protective paint for POF heat shrink film prepared using Showa JH-2630, after being pressed onto POF heat shrink film at 70 ℃ and with a 20 kg weight for 72 h, showed no oily gloss marks on the surface, with only a few bright spots; while the control sample using ordinary acrylic or polyurethane emulsions showed large oil spots, proving that the above-mentioned triple barrier mechanism of Showa JH-2630 effectively blocked the migration path of plasticizers.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A water-based white protective paint for POF heat shrink film, characterized in that, The raw materials include the following parts by weight: 50-60 parts of functional emulsion, 15-25 parts of white paste, 5-10 parts of functional additives, and 10-15 parts of water; the functional emulsion is a stain-resistant matte emulsion; the POF heat shrink film includes a plasticizer, which is a phthalate compound.

2. The water-based white protective paint for POF heat shrink film according to claim 1, characterized in that, The stain-resistant matte emulsion is an anionic emulsion, and its components include acrylate polymers. It has a matte finish of 10-15 GU at a 60° incident angle, stain resistance of <15%, solid content of 30-40℃, minimum film-forming temperature of ≥0℃, and pH value of 7.0-9.

0.

3. The water-based white protective paint for POF heat-shrinkable film according to claim 2, characterized in that, The stain-resistant matte emulsion is selected from Showa JH-2630.

4. The water-based white protective paint for POF heat-shrinkable film according to claim 1, characterized in that, The plasticizer accounts for 40-60% of the total mass of the POF heat shrink film.

5. The water-based white protective paint for POF heat-shrinkable film according to claim 1, characterized in that, The functional additives include one or more of the following: thickeners, wetting agents, defoamers, film-forming aids, matting materials, leveling agents, and anti-sagging agents.

6. The water-based white protective paint for POF heat-shrinkable film according to claim 5, characterized in that, The functional additives include 0.1-0.3 parts thickener, 0.4-0.6 parts wetting agent, 0.2-0.4 parts defoamer, 5-7 parts film-forming aid, 0.1-0.3 parts matting material, 0.4-0.6 parts leveling agent, and 1-3 parts anti-sagging agent.

7. The water-based white protective paint for POF heat-shrinkable film according to claim 1, characterized in that, The raw materials include the following parts by weight: 50-60 parts functional emulsion, 15-25 parts white paste, 0.1-0.3 parts thickener, 0.4-0.6 parts wetting agent, 0.2-0.4 parts defoamer, 5-7 parts film-forming aid, 0.1-0.3 parts matting material, 0.4-0.6 parts leveling agent, 1-3 parts anti-sagging aid, and 10-15 parts water; The stain-resistant matte emulsion is an anionic emulsion, and its components include acrylate polymers. It has a matte finish of 10-15 GU at a 60° incident angle, a stain resistance of <15%, a solid content of 30-40%, a minimum film-forming temperature of ≥0°C, and a pH value of 7.0-9.

0. The plasticizer accounts for 40-60% of the total mass of the POF heat-shrinkable film.

8. The method for preparing a water-based white protective coating for POF heat-shrinkable film according to any one of claims 1-7, characterized in that, Includes the following steps: At the first stirring speed, a portion of the thickener and a portion of the water are added to the functional emulsion, and the viscosity is adjusted to 50-60 seconds. Then, the defoamer, wetting agent, film-forming aid, matting material, and white paste are added. At the second stirring speed, the mixture is stirred until the fineness is below 30 microns. Then, the leveling agent, anti-sagging aid, the remaining thickener, and the remaining water are added.

9. The preparation method according to claim 8, characterized in that, The first stirring speed is 300-500 rpm; the second stirring speed is 800-1200 rpm.

10. The application of the water-based white protective paint for POF heat shrinkable film according to any one of claims 1-7, or the water-based white protective paint for POF heat shrinkable film prepared by the preparation method according to claim 8 or 9, on a workpiece, characterized in that, The POF heat shrink film-specific water-based white protective paint is applied to the workpiece, and the workpiece is wrapped with POF heat shrink film.

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