Method for modifying a surface of an olefinic resin comprising talc

Abstract

Provided is a method for modifying an olefin-based resin that can improve the adhesion of an olefin-based resin having talc on the surface to a paint. The method for modifying an olefin-based resin having talc on the surface includes the step of blowing a gas containing radicals generated by irradiating light to a gas containing chlorine dioxide toward the olefin-based resin at 10°C to 60°C.

Description

Technical Field

[0001] This invention relates to a method for modifying olefin resins with talc-containing surfaces. Background Technology

[0002] Patent Document 1 discloses a method for modifying a polymer, characterized by a reaction step of irradiating a reaction system containing a polymer with light in the presence of chlorine dioxide free radicals, wherein the wavelength of the light irradiating the reaction system exceeds 290 nm, the reaction system being either a gaseous reaction system containing the chlorine dioxide free radicals or a liquid reaction system containing the chlorine dioxide free radicals, the polymer containing carbon and hydrogen and having carbon-hydrogen bonds, and the carbon-hydrogen bonds of the polymer being oxidized in the reaction step.

[0003] Patent Document 1: Japanese Patent No. 7128496 Summary of the Invention

[0004] Olefin resins such as polypropylene have poor adhesion to coatings, so surface treatment is preferred before coating to improve adhesion. However, when the surface of the olefin resin contains talc, even the surface modification method described in Patent Document 1 cannot sufficiently improve adhesion to the coating.

[0005] Therefore, the present invention provides a method for modifying olefin resins that can improve the adhesion between olefin resins containing talc on the surface and coatings.

[0006] The present invention includes the following methods.

[0007] [Method 1]

[0008] A method for modifying olefin resins with talc-containing surfaces.

[0009] The method includes the following steps:

[0010] The olefin resin, which contains free radicals generated by irradiating a gas containing chlorine dioxide with light, is blown onto the resin at a temperature of 10°C to 60°C.

[0011] [Method 2]

[0012] According to the method of method 1, the olefin resin is a polypropylene resin.

[0013] [Method 3]

[0014] According to the method of method 1, the light is ultraviolet light.

[0015] [Method 4]

[0016] According to any one of methods 1 to 3, the gas containing free radicals is blown toward the olefin resin at a temperature of 20°C to 60°C.

[0017] [Method 5]

[0018] The method according to any one of methods 1 to 4 further includes the following steps:

[0019] The gas containing chlorine dioxide is generated in the chlorine dioxide gas generating section.

[0020] The gas containing chlorine dioxide is transported to the free radical generation unit;

[0021] In the free radical generation section, the gas containing chlorine dioxide is irradiated with light to generate free radicals, thereby generating the gas containing free radicals; and

[0022] The gas containing free radicals is transported to the processing unit.

[0023] In the processing unit, the surface of the olefin resin is modified by blowing the free radical-containing gas toward the olefin resin.

[0024] Invention Effects

[0025] The modification method of the olefin resin containing talc on the surface of the present invention can improve the adhesion between the olefin resin containing talc on the surface and the coating. Attached Figure Description

[0026] Figure 1 This is a diagram schematically illustrating an exemplary structure of an apparatus used for carrying out the method for modifying the olefinic resin involved in the embodiments.

[0027] Figure 2 This is a graph showing the relationship between temperature and breaking strength of polypropylene substrate. Detailed Implementation

[0028] Hereinafter, embodiments will be described with appropriate reference to the accompanying drawings, but the present invention is not limited to the embodiments described below. Various modifications, alterations, additions, omissions and / or combinations of the embodiments described below are possible without departing from the technical scope set forth in the claims.

[0029] In this application, unless otherwise specified, the numerical range represented by the symbol "~" includes each of the values ​​before and after the symbol "~" as the lower limit and upper limit. The upper and lower limits described in this application can be used individually or in any combination.

[0030] In this application, unless otherwise specified, "~comprises" and "~contains" mean that it can include additional components or elements, and include "~becomes essential" and "~comprises". "~becomes essential" means that it can include additional components or elements that will not substantially cause adverse effects. "~comprises" means that it includes only the described materials or elements, but does not exclude the inclusion of unavoidable impurities.

[0031] In this application, the term "and / or" means at least one of the listed items and all possible combinations thereof.

[0032] The method for modifying olefin resins with talc-containing surfaces involved in the embodiments will be described.

[0033] In this application, olefin-based resin refers to a resin that contains olefin units in an amount exceeding 50 mol% and less than 100 mol% based on all structural units constituting the resin. Furthermore, in the case where multiple structural units equivalent to olefin units are included, the total amount of all olefin units exceeds 50 mol% and is less than 100 mol%. Examples of olefin-based resins include polypropylene-based resins. In this application, polypropylene-based resin refers to a resin that contains propylene units in an amount exceeding 50 mol% and less than 100 mol% based on all structural units constituting the resin. Examples of polypropylene-based resins include propylene homopolymers (homopolymer polypropylene), propylene-α-olefin copolymers (random polypropylene), propylene block copolymers (block polypropylene), and combinations thereof.

[0034] Olefin resins may further include additives, fillers, and other components. Examples of additives include antioxidants, neutralizers, light stabilizers, ultraviolet absorbers, crystal nucleating agents, anti-adhesion agents, lubricants, antistatic agents, and metal passivators. One or more of these additives may be used. Examples of fillers include inorganic fillers such as calcium carbonate, silica, hydrotalcite, zeolite, aluminum silicate, magnesium silicate, glass fiber, and carbon fiber, as well as organic fillers such as cross-linked rubber microparticles, thermosetting resin microparticles, and thermosetting resin hollow microparticles.

[0035] The method for modifying an olefin resin containing talc on its surface according to the embodiments includes blowing a gas containing free radicals generated by irradiating a gas containing chlorine dioxide onto the olefin resin at a temperature of 10°C to 60°C.

[0036] An exemplary structure of the apparatus used to perform this modification method is shown in Figure 1 . Figure 1 The apparatus 1 shown has a chlorine dioxide gas generating unit 10, a free radical generating unit 20, and a processing unit 30.

[0037] Chlorine dioxide gas is generated in the chlorine dioxide gas generating section. Thus, a gas containing chlorine dioxide gas is generated in the chlorine dioxide gas generating section. The method for generating chlorine dioxide gas is not particularly limited. For example, chlorine dioxide gas can be generated from a mixture of chlorite (e.g., alkali metal salt, alkaline earth metal salt, or rare earth salt), acid, and water. Examples of chlorite include sodium chlorite (NaClO2), lithium chlorite (LiClO2), potassium chlorite (KClO2), magnesium chlorite (Mg(ClO2)2), and calcium chlorite (Ca(ClO2)2). From the viewpoint of cost and ease of handling, sodium chlorite (NaClO2) is preferred. The acid can be an inorganic acid or an organic acid. Examples of acids include hydrochloric acid, trifluoromethanesulfonic acid, trifluoroacetic acid, acetic acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, phosphoric acid, and phosphorous acid. For example, chlorine dioxide gas can be produced from a mixture of sodium chlorite, hydrochloric acid, and water.

[0038] The above mixture can be bubbled. The bubbling gas is not particularly limited; for example, it can be air.

[0039] The chlorine dioxide-containing gas obtained from the chlorine dioxide gas generating unit 10 is sent to the free radical generating unit 20. In the free radical generating unit 20, the chlorine dioxide-containing gas is irradiated with light to generate free radicals. Thus, a gas containing free radicals is generated. The free radicals can be chlorine dioxide free radicals. The irradiated light can be ultraviolet light, for example, having a wavelength of 200nm–400nm, 300nm–400nm, or 350nm–400nm.

[0040] In the processing unit 30, a talc-containing olefin resin is placed on its surface, and the olefin resin is heated to a temperature within the range of 10°C to 60°C or 20°C to 60°C. A gas containing free radicals obtained from the free radical generation unit 20 is sent to the processing unit 30 and blown onto the olefin resin. This process treats and modifies the surface of the olefin resin. A turbofan or similar device can be appropriately used when conveying the free radical-containing gas.

[0041] As shown in the examples described later, the coating can be adhered to the surface of the treated olefin resin with high adhesion.

[0042] Example

[0043] The present invention will be specifically described below through embodiments, but the present invention is not limited to these embodiments.

[0044] (1) Surface treatment of polypropylene substrate

[0045] (Comparative Examples 1-4)

[0046] In the chlorine dioxide gas generation unit, chlorine dioxide (ClO2) is generated by bubbling air while a solution of 25% by weight sodium chlorite aqueous solution, 9% by weight hydrochloric acid, and water in a specified ratio is supplied at the flow rate shown in Table 1. The generated mixture containing chlorine dioxide and air is then transported to the free radical generation unit by a turbine fan at a flow rate of 55 L / min. The concentration of chlorine dioxide in the mixture is shown in Table 1.

[0047] Free radicals are generated by irradiating the mixed gas with ultraviolet light at a wavelength of 365 nm through a free radical generation unit. The gas containing free radicals is then sent to a processing unit.

[0048] A talc-free polypropylene substrate is placed in the treatment section and maintained at the temperature described in Table 1. A free radical-containing gas supplied from the free radical generation section to the treatment section is blown onto the polypropylene substrate for 60 seconds.

[0049] (Examples 1-6, Comparative Examples 5 and 6)

[0050] A polypropylene substrate containing talc at a concentration of 15% by weight was used, and the flow rate of the liquid, the concentration of chlorine dioxide in the mixed gas, and the temperature of the polypropylene substrate were set as described in Table 1. Otherwise, the surface treatment of the polypropylene substrate was performed in the same manner as in Comparative Examples 1 to 4.

[0051] (2) XPS analysis of polypropylene

[0052] The surface of the treated polypropylene substrate was analyzed using X-ray photoelectron spectroscopy (XPS) under the following conditions. The results are shown in Table 1. Additionally, "C" in Table 1... O / C Cl "Indicates the ratio of O1s (mass%) to Cl2p (mass%).

[0053] Analytical apparatus: PHI 5000 VersaProbe II manufactured by ULVAC-PHI, Inc.

[0054] X-ray source: AlKα monochromatic light

[0055] Irradiation range: Φ100μm (1000×200μm)

[0056] Output: 25W

[0057] Voltage: 15kV

[0058] Neutralization Gun: Activate

[0059] Energy transfer (wide range): 187.85 eV

[0060] Step size (width): 0.4eV

[0061] Displacement correction: C1s: CC, CH 284.8 eV

[0062] Peak information: Handbook of XPS (ULVAC-PHI, Inc.)

[0063] (3) Fit evaluation

[0064] The treated polypropylene substrate was coated with a water-based paint (Kansai Paint Co., Ltd., WBC-717T, color code 8X8) and baked at 120°C for 20 minutes.

[0065] Peel tests were conducted using a frontal adhesion strength tester (DeFelsko PosiTest ATA20) to determine the breaking strength. The locations of failure were also visually examined after the tests. The results are shown in Table 1. When the failure site is at the interface between the polypropylene substrate and the coating, it indicates low adhesion between the polypropylene substrate and the coating; when the failure site is inside the polypropylene substrate, it indicates high adhesion between the polypropylene substrate and the coating. Figure 2 The figure shows the relationship between the temperature of a polypropylene substrate and its breaking strength when a gas containing free radicals is blown onto it.

[0066] In Comparative Examples 1-4 using talc-free polypropylene substrates, damage occurred within the polypropylene substrate regardless of substrate temperature, resulting in high adhesion between the polypropylene substrate and the water-based coating. In Examples 1-6, where a talc-containing polypropylene substrate was surface-treated at a temperature of 20°C to 60°C, damage also occurred within the polypropylene substrate, resulting in high adhesion between the polypropylene substrate and the water-based coating. However, in Comparative Examples 5 and 6, where a talc-containing polypropylene substrate was surface-treated at a temperature of 80°C, damage occurred at the interface between the polypropylene substrate and the coating, resulting in low adhesion between the polypropylene substrate and the coating. Therefore, it is evident that to improve adhesion by modifying the surface of a talc-containing polypropylene substrate, unlike with a talc-free polypropylene substrate, it is necessary to control the substrate temperature between 10°C and 60°C, particularly between 20°C and 60°C.

[0067] [Table 1]

[0068]

[0069] Symbol Explanation

[0070] 1-Apparatus, 10-Chlorine dioxide gas generating unit, 20-Free radical generating unit, 30-Processing unit.

Claims

1. A method for modifying an olefin resin with a surface containing talc, characterized in that, Includes the following steps: The olefin resin, which contains free radicals generated by irradiating a gas containing chlorine dioxide with light, is blown onto the resin at a temperature of 10°C to 60°C.

2. The method for modifying olefin resins with talc-containing surfaces according to claim 1, characterized in that, The olefin-based resin is a polypropylene-based resin.

3. The method for modifying olefin resins with talc-containing surfaces according to claim 1, characterized in that, The light is ultraviolet light.

4. The method for modifying an olefinic resin containing talc on its surface according to any one of claims 1 to 3, characterized in that, The gas containing free radicals is blown onto the olefin resin at a temperature of 20°C to 60°C.

5. A method for modifying an olefinic resin containing talc on its surface according to any one of claims 1 to 3, characterized in that, It also includes the following steps: The gas containing chlorine dioxide is generated in the chlorine dioxide gas generating section. The gas containing chlorine dioxide is transported to the free radical generation unit; In the free radical generation section, the gas containing chlorine dioxide is irradiated with light to generate free radicals, thereby generating the gas containing free radicals; and The gas containing free radicals is transported to the processing unit. In the processing unit, the surface of the olefin resin is modified by blowing the free radical-containing gas toward the olefin resin.

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