JP2011084628A - Method for modifying surface of polymer material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for modifying the surface of a polymer material, by which functional groups for imparting polarity to the surface of the polymer material can easily be produced even in a short treating time and in a large distance to the target material. <P>SOLUTION: The method for modifying the surface of the polymer material comprises a process for thermally treating the surface of the polymer material 2 and a process for applying surface modification for enlarging a wet tension value by a surface modification method of a dry method to the surface of the thermally treated polymer material 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to surface modification of a polymer material, and more particularly to a polymer material surface modification method for improving surface modification in a dry method.

  In recent years, it has been strongly desired to impart characteristics such as adhesiveness, dyeability, and wettability to the surface of a polymer material, and many researches on surface modification methods for polymer materials have been made. The surface modification technology for polymer materials includes a method in which an additive is added to the polymer material and the surface of the polymer is modified by surface diffusion from the inside of the polymer, as well as physical surface modification, chemical There is a method of performing from the outside of the polymer, such as surface modification by surface formation and surface modification by thin film formation. The external surface modification method can be classified into a wet method in which a solution is applied and a dry method in which no solution is used.

  When performing surface modification of a polymer material by a wet method, primer treatment or the like is employed. Primer treatment is a process for improving the adhesion between the adherend and adhesive by applying a low-viscosity liquid to improve the adhesion of the surface of the adherend and then applying an adhesive on it. is there. Therefore, the properties required for the wet method primer must have affinity for both the adherend and the adhesive.

  When surface modification of a polymer material is performed by a dry method, plasma treatment, ultraviolet (UV) irradiation treatment, frame treatment, corona treatment, and the like are employed. Plasma treatment is a treatment for modifying the surface of a polymer material with ions or radicals present in the plasma. The UV irradiation treatment is a treatment for activating the surface of the polymer material by irradiating the polymer material with UV. Flame treatment is a method of oxidizing the surface of a polymer material with a flame of a gas burner. By applying a flame of a burner at 2000 to 5000 ° C. to generate —COOH groups, —OH groups, etc., the adhesion is improved. It is a process to make. The corona treatment is a treatment in which the surface of the polymer material receives discharge energy and becomes activated by increasing the surface energy by causing a corona discharge phenomenon.

  In the dry method, the corona treatment is most commonly performed industrially. In corona treatment, for example, in order to obtain 73 mN / m as a level at which the surface of the polymer material gets wet with water, the treatment time has been increased or the distance between the discharge portion and the object has been reduced. Yes. However, since the temperature of the discharge portion during corona treatment partially reaches several hundred degrees, the surface of the polymer material may be burned (for example, see Patent Document 1).

JP-A-1-127315

  The present invention has been made in view of the above circumstances, and is a polymer material that is easy to generate functional groups that impart polarity on the surface of the polymer material even when the processing time is short and the distance to the object is large. An object is to provide a surface modification method.

  According to one embodiment of the present invention, a step of attaching water molecules to the surface of the polymer material, and a wet tension using a surface modification method that is a dry method on the surface of the polymer material to which the water molecules have adhered. The gist of the present invention is a polymer material surface modification method including a step of performing surface modification with a large value.

  According to the present invention, it is possible to provide a method for modifying the surface of a polymer material that is easy to generate a functional group that imparts polarity on the surface of the polymer material even when the treatment time is short and the distance to the object is large. it can.

It is typical sectional drawing which shows the process of the polymeric material surface modification method which concerns on embodiment of this invention. It is typical sectional drawing which shows the surface modification process in the polymeric material surface modification method which concerns on embodiment of this invention. It is a reference graph which shows the relationship between the numerical value of a surface treatment state, and adhesiveness.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in light of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(Embodiment)
The polymer material surface modification method according to the embodiment of the present invention includes a step of attaching water molecules to the surface of the polymer material 2 as shown in FIG. 1A and a method shown in FIG. In addition, a step of performing surface modification on the surface of the polymer material 2 to which water molecules are attached using a surface modification method that is a dry method increases the wet tension value. As the surface modification method that is a dry method, plasma treatment, ultraviolet (UV) irradiation treatment, flame treatment, corona treatment, or the like can be employed.

  The polymer material 2 is a polyolefin or the like. Polyolefins can be copolymerized with α-olefin homopolymers such as polyethylene and polypropylene, copolymers of α-olefins such as ethylene-propylene copolymers, and α-olefins such as ethylene-vinyl acetate copolymers. And a copolymer of a monomer other than an α-olefin and an α-olefin, a mixture thereof, and the like. Examples of the α-olefin include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene and the like. Examples of the monomer other than the α-olefin copolymerizable with the α-olefin include vinyl acetate, maleic acid, vinyl alcohol, methacrylic acid, methyl methacrylate, and ethyl methacrylate. These may be used alone or in combination of two or more.

  The polymer material 2 may be a single layer film or a laminated film in which two or more types of films having different properties are laminated. When a laminated film is employed for the polymer material 2, various combinations are used for the film forming each layer depending on the required performance.

In the step of attaching water molecules to the surface of the polymer material 2, as shown in FIG. 1A, a water tank 3 capable of storing the polymer material 2 is used. The water tank 3 is filled with a liquid 4 having water molecules (H ₂ O) to such an extent that the polymer material 2 is immersed.

  In the step of performing the surface modification of the polymer material 2, a surface modification apparatus 1 is used that performs surface modification of an object by a dry surface modification method. As the surface modification device 1, for example, there is a probe type surface modification device as shown in FIG. The probe type surface reforming apparatus sends air between the probe electrodes 10a and 10b with external air or an air pump, and applies a high voltage between the probe electrodes 10a and 10b as shown in FIG. It causes breakdown of air between 10b to generate atoms, molecules, electrons and ions, and causes a discharge phenomenon accompanied by pale light generated by the collision. When the discharge phenomenon occurs, the surface of the polymer material 2 receives the discharge energy, and the surface energy becomes high and activated.

  Examples of the polymer material surface modification method according to the embodiment will be described below.

  (A) First, the polymer material 2 is put into a water tank 3 filled with a liquid 4 having water molecules and immersed therein. The polymer material 2 is immersed in the liquid 4 for about 1 hour.

  (B) Next, as shown in FIG. 1B, the polymer material 2 is taken out of the water tank 3, and the liquid 4 adhering to the polymer material 2 is gently wiped off. At this time, the liquid 4 is wiped off so that water molecules remain on the surface of the polymer material 2. Then, the polymer material 2 having water molecules attached to the surface is transferred to the surface modification device 1.

  (C) Next, as shown in FIG. 1C, the polymer material 2 transferred to the surface modification device 1 keeps the distance between the probe electrodes 10a, 10b and the surface of the polymer material 2 at 5 mm, The surface modification device 1 is subjected to corona discharge to perform surface modification of the polymer material 2. The treatment time for surface modification of the polymer material 2 by the surface modification device 1 is 0.5 seconds.

  (D) Next, the wetting tension value of the polymer material 2 is measured by a wetting tension test method (JIS K6768). The wetting tension value of the polymer material 2 not subjected to surface modification (for example, polyethylene used for wire coating) was 30 mN / m as measured by the wetting tension test method. Further, the wetting tension value after removing the polymer material 2 from the water tank 3 and lightly wiping the liquid 4 adhering to the polymer material 2 was 34 mN / m. And the wet tension value of the surface of the polymeric material 2 which performed the surface modification process on said conditions in the state to which the water molecule has adhered was 73 mN / m.

  (E) Next, the surface of the polymer material 2 subjected to the surface modification treatment with water molecules attached is colored with acrylic ink, and after drying the ink, the ink part is peeled off using craft tape. To evaluate. As a result of evaluating the peeling of the ink part, the ink was peeled off in the polymer material 2 that was not subjected to the surface modification, and the ink was peeled off in the polymer material 2 that was subjected to the surface modification treatment with the water molecules attached There wasn't.

  A reference graph relating to the wetting tension value and the amount of ink peeling is shown in FIG. The upper surface shown in the graph of FIG. 3 is the side on which surface modification is performed directly by the surface modification device 1 of the sample (electric wire), and the lower surface is the back surface on the side where direct surface modification of the sample is performed. . From the graph of FIG. 3, in order for both the upper surface and lower surface peeling area ratios to be 30% or less, it can be achieved if the wetting tension value is 70 mN / m or more.

  As described above, when the polymer material 2 (for example, polyolefin) that has not undergone surface modification is colored, the ink used for coloring is peeled off immediately. On the other hand, when the polymer material surface modification method according to the embodiment was applied, the peeling of the ink used for coloring could be reduced, and the adhesion could be improved. This is because the polymer material 2 that has not undergone surface modification has a poor polarity that contributes to adhesion (coloring) on the surface of the polymer material 2, and the polymer material surface modification method according to the embodiment is applied. Thus, the polymer material 2 has sufficient polarity on the surface of the polymer material 2. That is, the polymer material surface modification method according to the embodiment can impart sufficient polarity to the surface of the polymer material 2.

A mechanism for imparting polarity to the surface of the polymer material 2 by performing the surface modification of the polymer material 2 by the polymer material surface modification method according to the embodiment of the present invention will be described. Giving polarity to the surface of the polymer material 2 means, for example, that oxygen (O ₂ ) in the air is reactive with oxygen radicals and oxygen plasma, as shown in the enlarged portion surrounded by the dotted line in FIG. By making it high, it reacts with the polymer material 2, and functional groups such as hydroxyl groups (—OH), carbonyl groups (> C═O), and carbonate groups (CO ₃ ) are formed on the surface of the polymer material 2. Is to generate. Then, by imparting polarity to the surface of the polymer material 2, the polymer material 2 is provided with characteristics such as adhesiveness, dyeability, and wettability.

When the surface modification treatment is further advanced, the ratio of not only hydroxyl groups, carbonyl groups, etc. but also carbonate groups on the surface of the polymer material 2 increases. Since the carbonic acid group has a three-dimensional structure, the bonding property with the binder is superior to the hydroxyl group and the carbonyl group, and features such as adhesiveness, dyeability, and wettability are further imparted.

  In addition, according to the polymer material surface modification method according to the embodiment of the present invention, a substance having a hydroxyl group considered as a functional group is obtained by performing the surface modification treatment with water molecules attached. Since it can be placed around the object and the polymer material 2 itself can be made to react easily, the surface modification treatment time is shortened and polarity is imparted even if the distance to the object is large. Functional groups can be generated.

  Moreover, according to the polymer material surface modification method according to the embodiment of the present invention, it is not necessary to separately arrange a gas cylinder or the like, and the cost can be reduced.

(Comparative example)
The polymer material 2 is disposed on the surface treatment apparatus. Then, the surface modification is performed under the same surface modification conditions as in the examples of the polymer material surface modification method according to the embodiment. Specifically, the polymer material 2 arranged in the surface modification device 1 maintains the distance between the probe electrodes 10a, 10b and the surface of the polymer material 2 at 5 mm, causes the surface modification device 1 to corona discharge, Surface modification of the molecular material 2 is performed. The treatment time for surface modification of the polymer material 2 by the surface modification device 1 is 0.5 seconds.

  As a result of performing the surface modification treatment with no water molecules attached, the wetting tension value of the surface of the polymer material 2 was 65 mN / m. In order to bring the wetting tension value of the surface of the polymer material 2 to 73 mN / m, the processing time took about 1 second.

  Therefore, in order to bring the wetting tension value of the surface of the polymer material 2 to a desired value in a state where water molecules are not attached, it is necessary to lengthen the treatment time.

(Other embodiments)
As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples, and operational techniques should be apparent to those skilled in the art.

  For example, in the polymer material surface modification method according to the embodiment, as a step of attaching water molecules to the surface of the polymer material 2, the polymer material 2 is introduced into a water tank 3 filled with a liquid 4 having water molecules. However, the present invention is not limited to this method, and a method in which water molecules are attached to the surface of the polymer material 2 by generating water vapor by humidification or the like can also be employed.

  In the polymer material surface modification method in the embodiment, the method using the corona treatment which is a dry method as the surface modification method is described, but the method is not limited to the corona treatment. As the surface modification method, for example, other dry methods such as plasma treatment, UV irradiation treatment, frame treatment, and the like may be adopted to modify the surface of the polymer material 2.

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters in the scope of claims reasonable from this disclosure.

DESCRIPTION OF SYMBOLS 1 ... Surface modification apparatus 2 ... Polymer material 3 ... Water tank 4 ... Liquid 10a, 10b ... Probe electrode

Claims (2)

Attaching water molecules to the surface of the polymer material;
Performing a surface modification on the surface of the polymer material to which the water molecules have adhered using a surface modification method that is a dry method to increase the wet tension value. Surface modification method.   The method for modifying a surface of a polymer material according to claim 1, wherein the step of modifying the surface generates a functional group that imparts polarity to the surface of the polymer material.

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