JP2005053947A - Method for treating surface of sheet-like plastic material, sheet-like plastic material and plastic joined body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for treating the surface of a sheet-like plastic material with which material cost is reduced without causing environmental pollution and without deteriorating appearance during processing and to provide the sheet-like plastic material and a plastic joined body. <P>SOLUTION: The method for treating the surface of the sheet-like plastic material is a method for treating the surface of the sheet-like plastic material 6. The surface 61 is subjected to a silicatising flame treatment. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface treatment method for a sheet-like plastic material, a sheet-like plastic material, and a plastic joined body.
[0002]
[Background]
Conventionally, crystalline resins such as polyolefin resins are inferior in transparency after molding due to their crystallinity, and their use has been limited. However, as the technology for controlling resin crystals has advanced, development of sheets and the like with higher transparency has progressed, and application to various containers has progressed.
Among them, assembly containers that punch sheets, bend creased sheets with crease lines, and bond the ends are different from ordinary containers and are not bulky before use and are suitable for storage and transportation. Often used as a packaging container.
When manufacturing these various containers, the process of adhering the above-mentioned sheet | seat etc. is needed. Therefore, adhesiveness is required for this sheet and the like. However, for example, polyolefin resins typified by polypropylene resins and polyethylene resins are resins that have extremely poor adhesion because they do not have polar groups.
In order to bond the polyolefin resin sheet or the like, a method is generally used in which the polyolefin resin sheet surface is treated with a primer (solvent system), and then an adhesive is applied and cured and adhered ( For example, see Patent Document 1).
In addition, a method is known in which the surface of a solid substrate is improved in printability by a method of modifying the surface of the solid substrate including an oxidation flame treatment step and a silicidation flame treatment step (see, for example, Patent Document 2).
[0003]
[Patent Document 1]
JP 2000-63768 A (first page)
[Patent Document 2]
JP 2002-53982 A (first page)
[0004]
[Problems to be solved by the invention]
However, according to the technique described in Patent Document 1, there is a problem that the material cost of the primer is high, a problem that requires a complicated process of applying and drying the primer, toluene, methyl acetate, methanol, etc. contained in the primer agent. The evaporation of the organic solvent is not only harmful to the human body, but also has sanitary problems due to the deterioration of the working environment and safety problems such as fires.
Further, in the technique described in Patent Document 2, there is mainly disclosure of inorganic substances such as glass and ceramic as the solid substrate, and for plastic, only the disclosure that the product is a bottle or a tube together with metal, No mention is made of sheet plastic. Furthermore, there is no disclosure of the adhesiveness of nonpolar plastic sheets such as polyolefin, especially primerless adhesion.
[0005]
The present invention has been made in view of the above problems. The object of the present invention is to reduce the cost of materials, to prevent the working environment from deteriorating, to be excellent in safety, and to treat the surface of a sheet-shaped plastic material that does not impair the appearance during processing, the sheet-shaped plastic material, and plastic bonding To provide a body.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the surface treatment method for a sheet-shaped plastic material according to the present invention is characterized in that the surface of the sheet-shaped plastic material is subjected to silicic acid flame treatment.
[0007]
Here, the silicic acid flame treatment is either a flammable gas, a mixed gas, an aerosol or a spray, which contains excess oxygen and / or has an oxidizing action in the presence of a silicon-containing compound. A silicon oxide layer is formed on the surface of the sheet-shaped plastic material by flame pyrolysis.
In particular, the silicon-containing layer can be formed almost without the presence of carbon, and during flame pyrolysis, an alkoxysilane as a silicon-containing compound is added to a gas mixture containing air, combustion gas, oxygen if necessary.
The flammable gas includes, for example, propane gas, butane, city gas and / or natural gas.
[0008]
According to the present invention, a silicon oxide layer is formed on the surface of the sheet-like plastic material by silicic acid flame treatment. This silicon oxide layer has a high density of reactive OH groups and improves the adhesion of the surface of the sheet-like plastic material. Therefore, the adhesiveness of the surface is good, it is not necessary to use a primer or the like, and a transparent adhesive can be used directly, so that the material cost can be reduced.
In addition, since there is no need to use a primer or the like, there is no concern about environmental pollution.
Furthermore, a transparent adhesive can be used, and when the sheet-like plastic material is bonded, the appearance is not impaired, and a container having excellent transparency can be obtained by folding with a ruled line.
[0009]
In the surface treatment method for a sheet-shaped plastic material according to the present invention, the silicic acid flame treatment can be performed on a part or the entire surface of the sheet, and is applied to at least a portion to which the sheet-shaped plastic material is bonded. It is preferable.
For example, if the surface of a sheet-shaped plastic material is large and the part to be bonded is considerably smaller than the surface, if the silicic acid flame treatment is applied to the entire surface, the majority of the material is wasted without being used for bonding. End up. That is, it may be processed in a portion corresponding to the conventional primer processing step.
According to this, it is not necessary to perform useless processing, and the manufacturing cost can be reduced.
[0010]
In the surface treatment method for a sheet-shaped plastic material according to the present invention, the sheet-shaped plastic material is preferably any one of a sheet, a film, a nonwoven fabric, and a woven fabric.
Here, a sheet | seat and a film mean that whose thickness is about 50-300 micrometers.
Here, as a method for producing the nonwoven fabric, methods such as a spunbond method, a melt blow method, a spunlace method, a hot air card method, a hot emboss card method, and a flash bond method can be employed.
Examples of the woven fabric include plain woven fabric, twill woven fabric, and satin woven fabric.
Here, the sheet-like plastic material includes a single-layer sheet, a film, a single-layer nonwoven fabric, a multilayer sheet having a different resin, a film, and a multilayer sheet-like material composed of a resin and a nonwoven fabric.
[0011]
In the surface treatment method for a sheet-shaped plastic material according to the present invention, the sheet-shaped plastic material is preferably made of a crystalline resin.
Here, examples of the crystalline resin include polyolefin resins, polyester resins, polyamide resins, and the like.
Among these, polyolefin resins are particularly preferable because of easy molding.
[0012]
Examples of the polyolefin resin include polypropylene resin, polyethylene resin, polybutene resin, and the like.
Among these, a polypropylene resin is particularly preferable because of its small specific gravity and light weight, rigidity, strength, and hinge characteristics.
As the polypropylene-based resin, homopropylene, random polypropylene, a mixture thereof, a low-crystalline modifying resin, and an elastomer may be blended.
In addition, as a polypropylene-based sheet, a melt-extruded sheet-like material is obtained by quenching using water, a metal belt or the like, a sheet formed by blending a nucleating agent, and further heat-treating these sheets. The known high transparency (haze 1 to 20% / 300 μm) and high rigidity (tensile elastic modulus 1500 to 4000 MPa) are preferable.
Examples of the polyethylene resin include linear low density polyethylene, low density polyethylene, and high density polyethylene.
[0013]
Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, and low crystalline or amorphous copolymer polyester.
Examples of the polyamide resin include nylon 66 and nylon 6.
According to this, since the sheet-like plastic material is made of a crystalline resin and exhibits high strength in the crystal structure of the resin, the sheet-like plastic material having high strength can be obtained.
[0014]
The sheet-like plastic material of the present invention is characterized in that the surface treatment of the aforementioned sheet-like plastic material is performed.
According to this, since the surface treatment of the above-mentioned sheet-like plastic material is performed, the same operations and effects as described above can be obtained.
[0015]
The plastic joined body of the present invention is characterized in that the aforementioned sheet-like plastic materials are bonded together with a transparent adhesive.
Here, examples of the plastic joined body include a clear box such as a bent container and a bent container, and a clear case.
Examples of the transparent adhesive include cyanoacrylate adhesives, epoxy adhesives, silicone adhesives, urethane adhesives, and the like.
Among these, cyanoacrylate adhesives that can be bonded instantaneously are particularly preferable.
[0016]
According to this, since this sheet-like plastic material is excellent in adhesiveness, it is not necessary to use a primer or the like, and a transparent adhesive can be used directly, so that the material cost can be reduced.
In addition, since there is no need to use a primer or the like, there is no concern about environmental pollution.
Further, by using a transparent adhesive, the appearance is not impaired when the sheet-like plastic material is bonded.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic diagram of a surface treatment method for a sheet-like plastic material 6 according to an embodiment of the present invention.
In the surface treatment method for a sheet-like plastic material according to the present embodiment, the surface 61 of the sheet-like plastic material 6 is subjected to silicic acid flame treatment.
The sheet-like plastic material 6 is a transparent sheet made of a polypropylene resin which is a crystalline resin (300 μm, haze 2%, tensile elastic modulus 2000 MPa).
[0018]
In the surface treatment method for a sheet-like plastic material (hereinafter sometimes simply referred to as a plastic material) of the present embodiment, a surface treatment apparatus 1 is used as shown in FIG. The surface treatment apparatus 1 is composed of a burner, and has a gas supply port 1A for supplying the mixed gas 7 and a jet port 1B for ejecting flame.
[0019]
As shown in FIG. 1, the plastic material 6 is fixed at a predetermined position from the jet nozzle 1 </ b> B of the surface treatment apparatus 1.
The distance between this jet nozzle 1B and the surface 61 of the plastic material 6 is about 30 to 150 mm. Next, the mixed gas 7 is supplied to the surface treatment apparatus 1 from the gas supply port 1A. The mixed gas 7 first comprises a flammable gas 71 and air 72. The volume ratio of these flammable gas 71 and air 72 is in the range of 1: 3 to 1:80.
The flammable gas 71 includes propane gas, butane gas, city gas, or natural gas. An oxidation flame is obtained by this mixed gas. Further, a silicon-containing compound 73 is contained in the mixed gas 7 and supplied to the surface treatment apparatus 1.
[0020]
In the present embodiment, the silicon-containing compound 73 is tetramethoxysilane, the mixed gas composed of flammable gas 71 and air 72, 10 ^- is added in ⁶ molar fraction of ^{- 2-10} .
[0021]
Then, the mixed gas 7 (flammable gas 71, air 72) and the silicon-containing compound 73 are combusted in the surface treatment apparatus 1, and a silicic acid flame is emitted from the ejection port 1B.
In addition, the temperature of this silicic acid flame is the range of 900-1200 degreeC, and the plastic material 6 is heated to 50-100 degreeC.
[0022]
By emitting this silicic acid flame, a silicon oxide layer 61A is formed on the surface. On the surface of the silicon oxide layer 61A, the density of reactive OH groups is particularly high.
As described above, the plastic material 6 subjected to the surface treatment of the plastic material according to the present invention is obtained.
In general, the surface treatment of the plastic material according to the present invention can employ a method in which the surface treatment apparatus is fixed and the plastic material is moved at a constant speed.
[0023]
The plastic material 6 described above is used as a base material of a clear package as a plastic joined body used for packaging and storage of cosmetics, pharmaceuticals, stationery, toys and the like.
This clear package is manufactured by bending the plastic material 6 and applying an adhesive process. When the bonding process is performed, the silicon oxide layers of the plastic material are made to correspond to each other and bonded with a transparent adhesive. This transparent adhesive is a cyanoacrylate adhesive.
[0024]
According to this embodiment as described above, the following effects are obtained.
(1) A silicon oxide layer 61A is formed on the surface by silicic acid flame treatment. This silicon oxide layer 61A has a high density of reactive OH groups, and the adhesion of the surface 61 of the plastic material 6 is improved. Therefore, the adhesiveness of the surface 61 is good, it is not necessary to use a primer or the like, and a transparent adhesive can be used directly, so that the material cost can be reduced. In addition, since there is no need to use a primer or the like, there is no concern about environmental pollution. Furthermore, a transparent adhesive can be used, and the appearance is not impaired when the plastic material 6 is bonded.
[0025]
(2) Since the silicon oxide layer 61A is formed only on the portion necessary for adhesion of the surface 61 of the plastic material 6, it is not necessary to perform wasteful processing, and the manufacturing cost can be reduced.
(3) Since the plastic material 6 is in the form of a sheet, the silicic acid flame is easily spread over the surface 61 of the plastic material 6 without being obstructed by irregularities or the like. Processing can be performed.
[0026]
(4) Since the plastic material 6 is made of a polypropylene-based resin that is a crystalline resin, the plastic material 6 exhibits a high strength in the crystal structure of the resin, so that the plastic material 6 having a high strength can be obtained. Moreover, a highly transparent and highly rigid sheet | seat is employable with the manufacturing method of a sheet | seat.
(5) The transparency of the plastic material 6 is not hindered by using a transparent adhesive during the bonding process for manufacturing the clear package. Further, since a cyanoacrylate adhesive that can be bonded instantaneously and is inexpensive is used, workability in manufacturing is improved.
It should be noted that the present invention is not limited to the above-described embodiment, and modifications and improvements within a scope that can achieve the object of the present invention are included in the present invention.
In the said embodiment, although the sheet | seat was employ | adopted as the plastic material 6, it is not restricted to this, A thinner film, a nonwoven fabric, a woven fabric, etc. are employable.
In the embodiment, the cyanoacrylate adhesive is used as the transparent adhesive, but is not limited thereto, and an epoxy adhesive, a silicone adhesive, a urethane adhesive, or the like can be used.
[0028]
In the above embodiment, the plastic material 6 is a sheet made of a polypropylene resin which is a crystalline resin, but is not limited to this, and is a sheet made of other polyolefin resin, polyester resin, polyamide resin or the like. May be.
Examples of the polyolefin resin include polyethylene resin and polybutene resin.
Examples of the polyester-based resin include polyethylene terephthalate, 1,4-cyclohexanedimethanol copolymerized low crystalline to amorphous polyethylene terephthalate, polybutylene terephthalate, and the like.
Examples of the polyamide resin include nylon 66 and nylon 6.
[0029]
In addition, the specific structure, shape, and the like when carrying out the present invention may be other structures and the like as long as the object of the present invention can be achieved.
[0030]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not limited to the content of the Example.
[Example 1]
In the said embodiment, the plastic material 6 used the Idemitsu Unitech Co., Ltd. transparent polypropylene sheet (Brand name super pure array sheet, thickness 0.3mm, haze 4.3%).
Using the plastic material 6 described above, the surface treatment method according to the present invention, that is, the surface treatment method for performing silicic acid flame treatment was carried out. Specifically, it implemented on the following conditions.
[0031]
Distance between jet outlet 1B and surface 61 of plastic material 6: 40 mm
Volume ratio of flammable gas 71 and air 72: 1:19
[0032]
Rate of addition of silicon-containing compound (tetramethoxysilane) 73 to mixed gas 7:
1 × 10 ⁻³ (molar fraction)
Temperature of silicic acid flame: about 1000 ° C
Surface temperature of plastic material 6 during silicic acid flame treatment: about 80 ° C.
Flame burning duration: 0.3 sec
In addition, there was no visual change in the transparency of the plastic material 6 obtained through the above surface treatment method.
[0033]
[Comparative Example 1]
The difference from Example 1 is that the surface treatment method of only the oxidation flame treatment was carried out.
[Comparative Example 2]
The difference from Example 1 is that no surface treatment was applied.
[0034]
[Evaluation methods]
A cyanoacrylate adhesive (Arteco MC-1) was applied to the treated surfaces of the plastic materials obtained in the above Examples and Comparative Examples 1, and two sheets were overlapped.
Moreover, the cyanoacrylate type adhesive agent was apply | coated to the plastic material of the comparative example 2, and two sheets were piled up.
For the plastic materials according to Example 1 and Comparative Examples 1 and 2, the joint surface was visually observed to judge transparency, and the adhesive strength of the joint surface was measured by a 180 degree peel test.
[0035]
[Evaluation results]
In Example 1, the curing of the cyanoacrylate adhesive progressed and adhesion was complete. The transparency of the joint surface after this adhesion did not change visually. The adhesive strength after curing of the adhesive was the strength at the material destruction level. Further, the surface-treated sheet was adhered in the same manner after being left at room temperature for 90 days, but the adhesion level was the strength of the material destruction level.
In Comparative Example 1, curing of the cyanoacrylate adhesive proceeded slowly and bonded. However, the adhesive strength after curing the adhesive was extremely small and could not withstand practical use.
In Comparative Example 2, curing of the cyanoacrylate-based adhesive did not proceed, and bonding could not be performed.
[0036]
According to the evaluation results of Example 1 and Comparative Example 1 described above, in Example 1, since a surface treatment including a silicic acid flame treatment was performed as compared with Comparative Example 1, a cyanoacrylate adhesive was used. It can be seen that the adhesive strength at the time was improved.
In Comparative Example 2, since the surface treatment was not performed, the bonding could not be performed.
[0037]
【The invention's effect】
According to the present invention, a silicon oxide layer is formed on the surface of the plastic material by silicic acid flame treatment. This silicon oxide layer has a high density of reactive OH groups and improves the adhesion of the surface of the plastic material. Accordingly, the adhesiveness of the surface is good, it is not necessary to use a primer or the like, and a transparent adhesive can be used directly, so that the material cost can be reduced. Moreover, since there is no need to use a primer or the like, there is no concern about environmental pollution. Furthermore, a transparent adhesive can be used, and the appearance is not impaired when the plastic material is bonded.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a surface treatment method according to an embodiment of the present invention.
[Explanation of symbols]
6 Sheet-like plastic material 61 Surface 61A Silicon oxide layer

Claims (10)

A surface treatment method for a sheet-like plastic material, characterized by subjecting the surface of the sheet-like plastic material to a silicic acid flame treatment. In the surface treatment method of the sheet-like plastic material according to claim 1,
The surface treatment method for a sheet-like plastic material, wherein the silicic acid flame treatment is applied to at least a portion to which the sheet-like plastic material is bonded. In the surface treatment method of the sheet-like plastic material according to claim 1 or 2,
The sheet-like plastic material is a sheet, a film, a nonwoven fabric, or a woven fabric. In the surface treatment method of the sheet-like plastic material according to any one of claims 1 to 3,
The sheet-shaped plastic material is made of a crystalline resin. In the surface treatment method of the sheet-like plastic material according to claim 4,
The method for surface treatment of a sheet-like plastic material, wherein the crystalline resin is a polyolefin resin. In the surface treatment method of the sheet-like plastic material according to claim 5,
The method for treating a surface of a sheet-like plastic material, wherein the polyolefin resin is a polypropylene resin. A sheet-like plastic material obtained by performing a surface treatment on the sheet-like plastic material according to any one of claims 1 to 6. A plastic joined body obtained by bonding the sheet-like plastic materials according to claim 7 with a transparent adhesive. The plastic joined body according to claim 8,
The plastic bonded body, wherein the transparent adhesive is a cyanoacrylate adhesive. The plastic joined body according to claim 8 or 9,
A plastic joined body characterized in that the joined body is a sheet bending and bonding assembly container.

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