Method for modifying olefin resins containing talc on the surface

Abstract

This invention provides a method for modifying olefin resins that can improve the adhesion between olefin resins containing talc on their surface and paints. [Solution] A method for modifying an olefin resin containing talc on its surface includes spraying a gas containing radicals generated by irradiating a gas containing chlorine dioxide with light onto the olefin resin at a temperature of 10°C to 60°C.

Description

Technical Field

[0001] The present disclosure relates to a method for modifying an olefin resin containing talc on the surface thereof.

Background Art

[0002] Patent Document 1 includes a reaction step of irradiating a reaction system containing a polymer with light in the presence of chlorine dioxide radicals, wherein in the reaction step, the wavelength of the light irradiated to the reaction system exceeds 290 nm, the reaction system is a gas reaction system containing the chlorine dioxide radicals or a liquid reaction system containing the chlorine dioxide radicals, the polymer contains carbon and hydrogen and has carbon-hydrogen bonds, and in the reaction step, the carbon-hydrogen bonds of the polymer are oxidized, which describes a method for modifying a polymer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0004] Olefin resins such as polypropylene have low adhesion to coatings, so it is desirable to perform surface treatment before applying the coating to improve the adhesion to the coating. However, when the olefin resin contains talc on its surface, the adhesion to the coating could not be sufficiently improved even by applying the surface modification method described in Patent Document 1.

[0005] Accordingly, the present disclosure provides a method for modifying an olefin resin, which can improve the adhesion between the olefin resin containing talc on the surface thereof and a coating material.

Means for Solving the Problems

[0006] Aspects of the present disclosure include the following. [Aspect 1] A method for modifying an olefin resin containing talc on its surface, A method comprising spraying a gas containing radicals generated by irradiating a gas containing chlorine dioxide with light onto an olefin-based resin at a temperature of 10°C to 60°C. [Aspect 2] The method according to embodiment 1, wherein the olefin resin is a polypropylene resin. [Aspect 3] The method according to embodiment 1, wherein the light is ultraviolet light. [Aspect 4] The method according to any one of embodiments 1 to 3, wherein the gas containing the radical is sprayed onto the olefin resin at 20°C to 60°C. [Aspect 5] In the chlorine dioxide gas generating unit, chlorine dioxide gas is generated to produce a gas containing the chlorine dioxide, The gas containing chlorine dioxide is sent to the radical generation unit, In the radical generation unit, the light is irradiated onto the gas containing chlorine dioxide to generate the radicals, thereby producing a gas containing the radicals. Sending the gas containing the radicals to the processing unit, It further includes, The method according to any one of embodiments 1 to 4, wherein in the processing stage, the gas containing the radical is blown onto the olefin resin to modify the surface of the olefin resin. [Effects of the Invention]

[0007] The method for modifying an olefin resin containing talc on the surface as disclosed herein can improve the adhesion between the olefin resin containing talc on the surface and the paint. [Brief explanation of the drawing]

[0008] [Figure 1] This figure schematically shows an exemplary configuration of an apparatus for performing a method for modifying an olefin-based resin according to an embodiment. [Figure 2] Figure 2 is a graph showing the relationship between polypropylene substrate temperature and fracture strength. [Modes for carrying out the invention]

[0009] Embodiments will be described below with reference to the drawings as appropriate, but this disclosure is not limited to the embodiments described below. Various modifications, changes, additions, omissions, and / or combinations of the embodiments described below are possible without departing from the technical scope set forth in the claims.

[0010] In this application, a numerical range represented by the symbol "~" includes the numerical values ​​before and after the symbol "~" as the lower and upper limits, respectively, unless otherwise specified. The upper and lower limits described in this application may be used individually or in any combination.

[0011] In this application, "containing" and "containing" mean that additional components or elements may be included unless otherwise specified, and encompass "essentially made of" and "consisting of." "Essentially made of" means that additional components or elements may be included that do not substantially adversely affect the product. "Consisting of" means that only the described material or element is included, but does not exclude the inclusion of unavoidable impurities.

[0012] In this application, the term "and / or" refers to at least one of the enumerated items and all possible combinations thereof.

[0013] A method for modifying an olefin resin containing talc on its surface according to this embodiment will be described.

[0014] In the present application, the olefin-based resin refers to a resin containing olefin units in an amount of more than 50 mol% and 100 mol% or less, based on all structural units constituting the resin. When a plurality of types of structural units corresponding to olefin units are contained, the total amount of all olefin units is more than 50 mol% and 100 mol% or less. Examples of the olefin-based resin include a polypropylene-based resin. In the present application, the polypropylene-based resin refers to a resin containing propylene units in an amount of more than 50 mol% and 100 mol% or less, based on all structural units constituting the resin. Examples of the polypropylene-based resin include propylene homopolymer (homopolypropylene), propylene-α-olefin copolymer (random polypropylene), propylene block copolymer (block polypropylene), and combinations thereof.

[0015] The olefin-based resin may further contain components such as additives and fillers. Examples of the additives include antioxidants, neutralizers, light stabilizers, ultraviolet absorbers, crystal nucleating agents, antiblocking agents, lubricants, antistatic agents, and metal deactivators. These additives may be used singly or in combination of two or more thereof. Examples of the fillers include inorganic fillers such as calcium carbonate, silica, hydrotalcite, zeolite, aluminum silicate, magnesium silicate, glass fibers, and carbon fibers, and organic fillers such as crosslinked rubber fine particles, thermosetting resin fine particles, and thermosetting resin hollow fine particles.

[0016] The method for modifying an olefin-based resin containing talc on the surface according to the embodiment includes spraying a radical-containing gas generated by irradiating a gas containing chlorine dioxide with light onto the olefin-based resin at 10°C to 60°C.

[0017] An exemplary configuration of an apparatus for performing this modification method is shown in Figure 1. The apparatus 1 shown in Figure 1 includes a chlorine dioxide gas generation unit 10, a radical generation unit 20, and a treatment unit 30.

[0018] In the chlorine dioxide gas generation unit, chlorine dioxide gas is generated. As a result, a gas containing chlorine dioxide gas is produced in the chlorine dioxide gas generation unit. The method of 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 chlorites include sodium chlorite (NaClO2), lithium chlorite (LiClO2), potassium chlorite (KClO2), magnesium chlorite (Mg(ClO2)2), and calcium chlorite (Ca(ClO2)2), with sodium chlorite (NaClO2) being preferred from the viewpoint of cost and ease of handling. The acid may 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, nitrite, phosphoric acid, and phosphorous acid. For example, chlorine dioxide gas may be generated from a mixture of sodium chlorite, hydrochloric acid, and water.

[0019] The above mixture may be bubbled. The bubbling gas is not particularly limited, but may be, for example, air.

[0020] The gas containing chlorine dioxide obtained in the chlorine dioxide gas generation unit 10 is sent to the radical generation unit 20. In the radical generation unit 20, light is irradiated onto the gas containing chlorine dioxide to generate radicals. This produces a gas containing radicals. The radicals may be chlorine dioxide radicals. The irradiated light may be ultraviolet light and may have wavelengths such as 200 nm to 400 nm, 300 nm to 400 nm, or 350 nm to 400 nm.

[0021] In the processing unit 30, an olefin resin containing talc on its surface is placed, and the olefin resin has a temperature in the range of 10°C to 60°C or 20°C to 60°C. A gas containing radicals obtained in the radical generation unit 20 is sent to the processing unit 30 and blown onto the olefin resin. As a result, the surface of the olefin resin is treated and modified. A turbo fan or the like may be used as appropriate for transporting the gas containing radicals.

[0022] As shown in the examples described later, paint can be adhered to the surface of the treated olefin resin with high adhesion. [Examples]

[0023] The present disclosure will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0024] (1) Surface treatment of polypropylene substrate (Comparative Examples 1-4) In the chlorine dioxide gas generation unit, a chemical solution prepared by mixing 25% by weight sodium chlorite aqueous solution, 9% by weight hydrochloric acid, and water in predetermined proportions was supplied at the flow rates shown in Table 1 while bubbling with air to generate chlorine dioxide (ClO2). The generated chlorine dioxide and air-containing mixed gas was sent to the radical generation unit at a flow rate of 55 L / min by a turbo fan. The concentration of chlorine dioxide in the mixed gas was as shown in Table 1.

[0025] In the radical generation unit, radicals were generated by irradiating a mixed gas with ultraviolet light at a wavelength of 365 nm. The gas containing the radicals was then sent to the processing unit.

[0026] A talc-free polypropylene substrate was placed in the treatment area and maintained at the temperature shown in Table 1. A gas containing radicals, supplied from the radical generation unit to the treatment area, was blown onto the polypropylene substrate for 60 seconds.

[0027] (Examples 1-6, Comparative Examples 5, 6) The surface treatment of the polypropylene substrate was carried out in the same manner as in Comparative Examples 1 to 4, except that a polypropylene substrate containing talc at a concentration of 15% by weight was used, and the flow rate of the chemical solution, the concentration of chlorine dioxide in the mixed gas, and the temperature of the polypropylene substrate were as shown in Table 1.

[0028] (2) XPS analysis of polypropylene The surface of the treated polypropylene substrate was analyzed by X-ray photoelectron spectroscopy (XPS) under the following conditions. The results are shown in Table 1. Note that "C" in Table 1 refers to... O / C Cl This represents the ratio of O1s (mass%) to Cl2p (mass%).

[0029] Analytical instrument: ULVAC-PHI PHI 5000 VersaProbe II X-ray source: AlKα monochromatic light Irradiation area: Φ100μm (1000×200μm) Output: 25W Voltage: 15kV Neutralizing gun: ON Path energy (wide): 187.85 eV Step width (wide): 0.4eV Shift compensation: C1s: CC, CH 284.8eV Peak Information: Handbook of XPS (ULVAC-PHI, Inc.)

[0030] (3) Adhesion evaluation A water-based paint (WBC-717T, color code 8X8, manufactured by Kansai Paint Co., Ltd.) was applied to the surface of the treated polypropylene substrate and baked at 120°C for 20 minutes.

[0031] Peel tests were performed using a PosiTest adhesion tester (DeFelsko PosiTest ATA20), and the fracture strength was measured. The fracture location was also visually inspected after the test. The results are shown in Table 1. If the fracture location was at the interface between the polypropylene substrate and the paint, it indicates low adhesion between the polypropylene substrate and the paint; if the fracture location was inside the polypropylene substrate, it indicates high adhesion between the polypropylene substrate and the paint. Figure 2 shows the relationship between the polypropylene substrate temperature and fracture strength when a gas containing radicals was sprayed onto the polypropylene substrate.

[0032] In Comparative Examples 1-4, which used polypropylene substrates without talc, fracture occurred within the polypropylene substrate regardless of the substrate temperature, and the adhesion between the polypropylene substrate and the water-based paint was high. In Examples 1-6, where the surface treatment was performed at a temperature of 20°C to 60°C on polypropylene substrates containing talc, fracture also occurred within the polypropylene substrate, and the adhesion between the polypropylene substrate and the water-based paint was high. However, in Comparative Examples 5 and 6, where the surface treatment was performed at a temperature of 80°C on polypropylene substrates containing talc, fracture occurred at the interface between the polypropylene substrate and the paint, and the adhesion between the polypropylene substrate and the paint was low. Therefore, it was shown that, unlike polypropylene substrates without talc, it is necessary to control the substrate temperature to 10°C to 60°C, especially 20°C to 60°C, in order to modify the surface of polypropylene substrates containing talc and improve adhesion.

[0033] [Table 1] [Explanation of Symbols]

[0034] 1 apparatus, 10 chlorine dioxide gas generating unit, 20 radical generating unit, 30 processing unit 30

Claims

1. A method for modifying an olefin resin containing talc on its surface, A method comprising spraying a gas containing radicals generated by irradiating a gas containing chlorine dioxide with light onto an olefin resin at a temperature of 10°C to 60°C.

2. The method according to claim 1, wherein the olefin resin is a polypropylene resin.

3. The method according to claim 1, wherein the light is ultraviolet light.

4. The method according to any one of claims 1 to 3, wherein the gas containing the radicals is sprayed onto the olefin resin at 20°C to 60°C.

5. In the chlorine dioxide gas generating unit, chlorine dioxide gas is generated to produce a gas containing the chlorine dioxide, The gas containing chlorine dioxide is sent to the radical generation unit, In the radical generation unit, the light is irradiated onto the gas containing chlorine dioxide to generate the radicals, thereby producing a gas containing the radicals. Sending the gas containing the radicals to the processing unit, It further includes, The method according to any one of claims 1 to 3, wherein in the processing stage, the gas containing the radical is blown onto the olefin resin to modify the surface of the olefin resin.

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