All-aqueous phase polypropylene surface wetting agent and preparation method and application thereof

Abstract

The present application relates to a kind of full aqueous phase polypropylene surface wetting agent and its preparation method and application, the present application with acrylic acid (AA) as raw material, octadecyl methacrylate (SMA) as hydrophobic monomer, 2-methyl-2-acrylic acid-2-(2-oxo-1-imidazoline group) ethyl ester as functional monomer, sodium lauryl sulfate (SLS) as surfactant, ammonium persulfate (APS) as initiator, successfully prepared full aqueous phase polypropylene surface wetting agent.Polypropylene plastic film is immersed into full aqueous phase polypropylene surface wetting agent solution, greatly improve the nonpolarity of polypropylene, solve the problem of poor adhesion in the prior art when spraying polypropylene and other low surface energy nonpolar polymer materials.

Description

Technical Field

[0001] This invention relates to an all-aqueous polypropylene surface wetting agent, its preparation method and application, belonging to the field of polymer materials technology. Background Technology

[0002] The non-polar molecular structure of polypropylene results in low surface energy (approximately 30 mN / m), making it difficult for liquids (such as water, adhesives, and inks) to spread on its surface, easily forming droplets and leading to poor adhesion. The main purpose of spraying a wetting agent onto the polypropylene (PP) surface is to improve its surface properties and enhance the interfacial bonding between the agent and the coating, thereby addressing the inherent problems of polypropylene itself.

[0003] Currently, methods for improving the wettability of PP surfaces are mainly divided into two categories: physical modification and material modification. Physical modification methods include corona treatment, plasma treatment, and laser treatment. Corona treatment generates active free radicals on the PP surface through high-voltage discharge, introducing polar groups (such as hydroxyl and carbonyl groups). However, this method only affects the shallow surface layer, and the surface active groups easily decay over time, resulting in poor long-term stability. Although plasma treatment effectively improves the surface chemical structure of polypropylene, its expensive equipment and low processing efficiency make it difficult to achieve large-scale industrial production. Laser treatment suffers from high equipment costs, sensitivity to process parameters, and may cause thermal damage to the PP substrate, affecting its mechanical properties.

[0004] Chemical modification methods mainly involve surface grafting, coating, and adding surfactants. Coating and adding surfactants are relatively simple methods to improve the wettability of PP surfaces, but both suffer from poor interfacial compatibility with the PP substrate, leading to delamination and peeling.

[0005] Therefore, developing a wetting agent that is compatible with the PP matrix and can improve the wettability of the PP surface is of great practical significance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, especially the problems of poor interfacial compatibility between existing chemical modification methods and PP substrates, as well as the susceptibility to precipitation and delamination caused by other solvents, this invention provides an all-aqueous polypropylene surface wetting agent, its preparation method, and its application.

[0007] This invention successfully prepared an all-aqueous polypropylene surface wetting agent using acrylic acid (AA) as raw material, octadecyl methacrylate (SMA) as a hydrophobic monomer, 2-methyl-2-acrylate-2-(2-oxo-1-imidazolinyl)ethyl ester as a functional monomer, sodium dodecyl sulfate (SLS) as a surfactant, and ammonium persulfate (APS) as an initiator. Immersing a polypropylene plastic film in the all-aqueous polypropylene surface wetting agent solution significantly improves the non-polarity of polypropylene, solving the problem of poor adhesion when spraying low surface energy non-polar polymer materials such as polypropylene in existing technologies.

[0008] This invention is achieved through the following technical solution:

[0009] On one hand, the present invention provides a method for preparing an all-aqueous polypropylene surface wetting agent, comprising the following steps:

[0010] (1) Heat deionized water to 70-90℃, add acrylic acid (AA), octadecyl methacrylate (SMA), 2-methyl-2-acrylate-2-(2-oxo-1-imidazolinyl)ethyl ester and sodium dodecyl sulfate (SLS), and stir until the reaction solution is homogeneous;

[0011] (2) Add ammonium persulfate (APS) solution to the system in step (1) and keep it warm for 2-6 hours to initiate free radical polymerization. The reaction temperature is always kept at 70-90℃.

[0012] (3) After the reaction is complete, cool down and slowly add ammonia water to adjust the pH of the reaction solution to 8 so that the carboxylic acid groups are fully neutralized into ammonium salts, and an all-aqueous polypropylene surface wetting agent is obtained.

[0013] According to a preferred embodiment of the present invention, in step (1), the mass ratio of acrylic acid (AA) to octadecyl methacrylate (SMA) is (50-95):(5-30).

[0014] According to a preferred embodiment of the present invention, in step (1), the mass ratio of acrylic acid (AA) to deionized water is (20-50):(50-80).

[0015] According to a preferred embodiment of the present invention, in step (1), the mass ratio of octadecyl methacrylate (SMA) to sodium dodecyl sulfate (SLS) is 100:(1-5).

[0016] According to a preferred embodiment of the present invention, in step (1), the mass ratio of octadecyl methacrylate (SMA) to 2-methyl-2-acrylate-2-(2-oxo-1-imidazolinyl)ethyl ester is (20-50):(50:80).

[0017] According to a preferred embodiment of the present invention, in step (2), the mass concentration of the ammonium persulfate (APS) solution is 4-8 wt%.

[0018] According to a preferred embodiment of the present invention, in step (2), the mass ratio of acrylic acid (AA) to ammonium persulfate (APS) solution is 100:(0.1-1).

[0019] According to a preferred embodiment of the present invention, in step (3), the temperature is lowered to 45-55°C after the reaction is completed.

[0020] According to a preferred embodiment of the present invention, in step (3), the mass concentration of ammonia water is 5-15 wt%.

[0021] According to a preferred embodiment of the present invention, in step (3), the amount of ammonia added is 1.05-1.2 times the mass of acrylic acid.

[0022] In another aspect, the present invention provides an all-aqueous polypropylene surface wetting agent, which is prepared by the above method.

[0023] In another aspect, the present invention provides an application of an all-aqueous polypropylene surface wetting agent for surface modification of polypropylene.

[0024] According to a preferred embodiment of the present invention, the specific application method is as follows: immerse the polypropylene film in an all-aqueous polypropylene surface wetting agent for 10-30 seconds, and then dry it at 50-70°C for 4-8 hours.

[0025] According to a preferred embodiment of the present invention, the polypropylene film is prepared by the following method:

[0026] 1) Polypropylene (PP) masterbatch, compatibilizer, and antioxidant are extruded using a twin-screw extruder at an extrusion temperature of 250°C.

[0027] 2) The extruded PP is hot-pressed into a film using a hot press to obtain a polypropylene film; the hot pressing temperature is 200℃ and the pressure is 150 psi.

[0028] According to a preferred embodiment of the present invention, the compatibilizer is maleic anhydride-grafted polypropylene or acrylic acid-grafted polypropylene.

[0029] According to a preferred embodiment of the present invention, the antioxidant is antioxidant 1010 or antioxidant 330.

[0030] According to a preferred embodiment of the present invention, the mass ratio of compatibilizer to antioxidant is (0.1-0.5):(0.5-1.5).

[0031] According to a preferred embodiment of the present invention, the mass ratio of polypropylene (PP) masterbatch to compatibilizer is 100:1.

[0032] Technical features and advantages of the present invention:

[0033] 1. Polar monomers (acrylic acid) are polymerized simultaneously with hydrophobic monomers and functional monomers, avoiding the need for stepwise synthesis and coupling of polar and hydrophobic segments required in traditional block copolymers. This shortens the process flow and reduces intermediate product loss. Hydrophobic alkyl chains are introduced.

[0034] 2. The reaction system is aqueous, which is green and environmentally friendly. In solution polymerization, hydrophobic monomers are uniformly grafted onto the polyacrylic acid chains to form a regular comb-like structure of "polar chain-hydrophobic chain-functional chain", avoiding the problems of uneven dispersion or phase separation caused by traditional physical compounding methods (such as mechanical blending of polyacrylic acid and paraffin). Attached Figure Description

[0035] Figure 1 The water contact angle is the polypropylene plastic film of Examples 1-3 and Comparative Example 1.

[0036] Figure 2 This is a scanning electron microscope image of the polypropylene film after it has been impregnated with a wetting agent, as shown in Example 1. Detailed Implementation

[0037] The present invention will be further described below through specific embodiments, but these are not intended to limit the scope of the invention.

[0038] The raw materials used in the examples are commercially available or can be prepared using existing technologies.

[0039] In the examples, the polypropylene film was prepared by the following method:

[0040] 1) Polypropylene (PP) masterbatch, compatibilizer and antioxidant are extruded through a twin-screw extruder at an extrusion temperature of 250°C. The weight parts of PP masterbatch are 98 parts, compatibilizer is 0.5 parts, and antioxidant is 1.5 parts.

[0041] 2) The extruded PP is hot-pressed into a film using a hot press to obtain a polypropylene film; the hot pressing temperature is 200℃ and the pressure is 150 psi.

[0042] Example 1

[0043] The preparation method of the all-aqueous polypropylene surface wetting agent is as follows:

[0044] 1) Add deionized water to the reactor and heat to 80°C. Add 80 parts of AA, 10 parts of SMA, 30 parts of 2-methyl-2-acrylate-2-(2-oxo-1-imidazolinyl)ethyl ester, and 0.1 parts of SLS. Then stir the mixture until completely dissolved.

[0045] 2) Dissolve APS in deionized water to prepare a 5% (w / w) solution. Add the APS solution to step 1) and keep it warm for 3 h to initiate free radical polymerization. Observe the reaction temperature at all times and keep it at 80℃.

[0046] 3) When the reaction solution is cooled to 50°C, ammonia water is slowly added dropwise, and the pH of the reaction solution is adjusted to 8 to obtain an all-aqueous polypropylene surface wetting agent.

[0047] A polypropylene film was immersed in an all-aqueous polypropylene surface wetting agent for 10 seconds, then removed and placed in a forced-air drying oven for 6 hours at a drying temperature of 60°C. The weight gain of the polypropylene film before and after immersion in the wetting agent was then measured.

[0048] Example 2

[0049] The preparation method of the all-aqueous polypropylene surface wetting agent is as follows:

[0050] 1) Add deionized water to the reactor and heat to 80°C. Add 60 parts of AA, 10 parts of SMA, 20 parts of 2-methyl-2-acrylate-2-(2-oxo-1-imidazolinyl)ethyl ester, and 0.1 parts of SLS. Then stir the mixture until completely dissolved.

[0051] 2) Dissolve APS in deionized water to prepare a 5% (w / w) solution. Add the APS solution to step 1) and keep it warm for 3 h to initiate free radical polymerization. Observe the reaction temperature at all times and keep it at 80℃.

[0052] 3) When the reaction solution is cooled to 50°C, ammonia water is slowly added dropwise, and the pH of the reaction solution is adjusted to 8 to obtain an all-aqueous polypropylene surface wetting agent.

[0053] A polypropylene film was immersed in an all-aqueous polypropylene surface wetting agent for 20 seconds, then removed and placed in a forced-air drying oven for 6 hours at a drying temperature of 60°C. The weight gain of the polypropylene film before and after immersion in the wetting agent was then measured.

[0054] Example 3

[0055] The preparation method of the all-aqueous polypropylene surface wetting agent is as follows:

[0056] 1) Add deionized water to the reactor and heat to 80°C. Add 50 parts of AA, 10 parts of SMA, 10 parts of 2-methyl-2-acrylate-2-(2-oxo-1-imidazolinyl)ethyl ester, and 0.1 parts of SLS. Then stir the mixture until completely dissolved.

[0057] 2) Dissolve APS in deionized water to prepare a 5% (w / w) solution. Add the APS solution to step 1) and keep it warm for 3 h to initiate free radical polymerization. Observe the reaction temperature at all times and keep it at 80℃.

[0058] 3) When the reaction solution is cooled to 50°C, ammonia water is slowly added dropwise, and the pH of the reaction solution is adjusted to 8 to obtain an all-aqueous polypropylene surface wetting agent.

[0059] A polypropylene film was immersed in an all-aqueous polypropylene surface wetting agent for 30 seconds, then removed and placed in a forced-air drying oven for 6 hours at a drying temperature of 60°C. The weight gain of the polypropylene film before and after immersion in the wetting agent was then measured.

[0060] Comparative Example 1

[0061] 98 parts of PP masterbatch, 0.5 parts of compatibilizer, and 1.5 parts of antioxidant were extruded using a twin-screw extruder at an extrusion temperature of 250°C. The extruded PP was then hot-pressed into a film using a hot press at an extrusion temperature of 200°C and a pressure of 150 psi.

[0062] Experiment Example 1: Water Contact Angle Test of Polypropylene Plastic Impregnated with Hydrophobic Modified Ammonium Polyacrylate Wetting Agent

[0063] 1. Measure the water contact angle of a polypropylene plastic film using a fully automatic video optical contact angle meter (OCA50). Gently wipe the surface of the polypropylene plastic film with a cotton ball, then place it on the experimental table to perform the water contact angle test. The test results are shown below. Figure 1 Table 1.

[0064] pass Figure 1 As can be seen from Table 1, the water contact angle of the polypropylene plastic film of the present invention is much smaller than that of Comparative Example 1. It can be seen that the wetting agent of the present invention greatly improves the non-polarity of polypropylene.

[0065] Table 1. Water contact angles of the polypropylene plastic impregnation wetting agents in Examples 1-3 and Comparative Example 1

[0066]

[0067] 2. Scanning electron microscopy of the polypropylene film after impregnation with wetting agent in Example 1 (see image). Figure 2 As can be seen from the scanning electron microscope images, the prepared wetting agent has good interfacial adhesion between PP substrates and no obvious delamination problem occurs.

Claims

1. A method for preparing an all-aqueous polypropylene surface wetting agent, comprising the following steps: (1) Heat deionized water to 70-90℃, add acrylic acid (AA), octadecyl methacrylate (SMA), 2-methyl-2-acrylate-2-(2-oxo-1-imidazolinyl)ethyl ester and sodium dodecyl sulfate (SLS), and stir until the reaction solution is homogeneous; (2) Add ammonium persulfate (APS) solution to the system in step (1) and keep it warm for 2-6 hours to initiate free radical polymerization. The reaction temperature is always kept at 70-90℃. (3) After the reaction is complete, cool down and slowly add ammonia water to adjust the pH of the reaction solution to 8 so that the carboxylic acid groups are fully neutralized into ammonium salts, and an all-aqueous polypropylene surface wetting agent is obtained.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of acrylic acid (AA) to octadecyl methacrylate (SMA) is (50-95):(5-30).

3. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of acrylic acid (AA) to deionized water is (20-50): (50-80).

4. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of octadecyl methacrylate (SMA) to sodium dodecyl sulfate (SLS) is 100:(1-5).

5. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of octadecyl methacrylate (SMA) to 2-methyl-2-acrylate-2-(2-oxo-1-imidazolinyl)ethyl ester is (20-50):(50:80).

6. The preparation method according to claim 1, characterized in that, In step (2), the mass concentration of ammonium persulfate (APS) solution is 4-8 wt%, and the mass ratio of acrylic acid (AA) to ammonium persulfate (APS) solution is 100:(0.1-1).

7. The preparation method according to claim 1, characterized in that, In step (3), after the reaction is completed, the temperature is lowered to 45-55℃, the mass concentration of ammonia is 5-15wt%, and the amount of ammonia added is 1.05-1.2 times the mass of acrylic acid.

8. An all-aqueous polypropylene surface wetting agent, prepared by any one of the methods described in claims 1-7.

9. The application of the all-aqueous polypropylene surface wetting agent according to claim 1, used for surface modification of polypropylene, the specific application method is as follows: immerse the polypropylene film in the all-aqueous polypropylene surface wetting agent for 10-30 s, and then dry it at 50-70℃ for 4-8 h.

10. The application according to claim 9, characterized in that, Polypropylene film is prepared by the following method: 1) Polypropylene (PP) masterbatch, compatibilizer, and antioxidant are extruded using a twin-screw extruder at an extrusion temperature of 250°C. 2) The extruded PP is hot-pressed into a film using a hot press to obtain a polypropylene film; the hot pressing temperature is 200℃, the pressure is 150psi, the compatibilizer is maleic anhydride-grafted polypropylene or acrylic acid-grafted polypropylene, the antioxidant is antioxidant 1010 or antioxidant 330, the mass ratio of compatibilizer to antioxidant is (0.1-0.5):(0.5-1.5), and the mass ratio of polypropylene PP masterbatch to compatibilizer is 100:1.

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