JPH0249035A - Polyphenylene sulfide film - Google Patents

Abstract

PURPOSE:To obtain the title film having both high thermal fusing properties and wet releasability comprising carbon atom bonded to oxygen atom in a ratio of specific range and sulfur atom bonded to oxygen atom in a specific state in a ratio of a specific range on the surface of film. CONSTITUTION:The surface or both sides of a film containing >=80wt.% poly-p- phenylene sulfide having a repeating unit shown by the formula and 0.4-100mum thickness is subjected to low-temperature plasma treatment in a mixed gas (preferably mixed gas of inert gas such as argon, oxygen and nitrogen) atmosphere under a plasma condition to give the aimed film comprising 3-20wt.% ratio of carbon atom bonded to oxygen atom based on total carbon atoms on the surface and 3-35wt.% ratio of sulfur atom bonded to oxygen atom in a state of sulfonic acid, sulfonate ion or sulfonate based on total sulfur atoms.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polyphenylene sulfide film, and more specifically, a polyphenylene sulfide film that normally exhibits strong thermal adhesive properties.
In addition, the present invention relates to a polyphenylene sulfide film that can be easily peeled off simply by supplying moisture to the bonding interface when peeling is desired, and can be effectively used for release films, protective films, labels, stickers, tapes, etc.

[Prior Art] It is well known that polyenylene sulfite films do not have thermal bonding properties and cannot be thermally bonded to films of the same type or to films of different types.

Conventionally, in order to improve the thermal adhesion of such polyphenylene sulfite films, it has been proposed to perform corona discharge treatment or plasma treatment (Japanese Patent Application Laid-Open No. 18732-1989).
Publication No. 7).

[Problems to be Solved by the Invention] However, as a result of further detailed study by the present inventors, it was found that the corona discharge treatment described above has the following problems.

In other words, the polyphenylene sulfide film subjected to the Corona 11i electric treatment has thermal adhesiveness or self-adhesiveness immediately after treatment, as well as releasability due to moisture supply (hereinafter referred to as wet peelability), but immediately after treatment, the polyphenylene sulfide film exhibits thermal adhesiveness or self-adhesiveness. There is a problem in that the thermal adhesiveness gradually decreases over time, and after a few minutes, the thermal adhesiveness significantly decreases.

In addition, when using the plasma treatment method specifically disclosed in the above-mentioned article, that is, when a polyphenylene sulfide film is subjected to plasma treatment in an argon atmosphere, its self-bonding property (thermal bonding property) is investigated. It was found that although the dry adhesion strength was sufficiently high, the welding strength was similarly high, and as a result, the wet releasability, that is, the releasability due to moisture supply, was significantly reduced.

The inventors of the present invention have made extensive inquiries into ways to improve the problems of the prior art, and have found that when the surface of a polyphenylene sulfide film is modified to have a specific chemical structure, sufficient heat-fusibility or self-adhesiveness can be achieved. It was discovered that the present invention has fusible properties and can be easily peeled off from the bonded surface by simply supplying moisture to the bonded surface, and that the thermal bonding and wet peelability do not deteriorate over time. has been reached.

Therefore, an object of the present invention is to provide a polyphenylene sulfide film that has strong thermal adhesive properties under normal conditions and can be easily peeled off simply by supplying moisture to the bonded interface when peeling is desired.

[Means for Solving the Problems] The object of the present invention is to reduce the ratio of carbon atoms bonded to oxygen atoms to all carbon atoms on the surface from 3% to 20%.
%, and the ratio of sulfur atoms bonded to oxygen atoms in the form of sulfonic acid, sulfonate ions or sulfonate to sulfur atoms is 3% to 35%.
This is achieved by a polyphenylene sulfide film having a characteristic fjl in the range of fjl.

The polyphenylene sulfide film used in the present invention refers to a film consisting of the following repeating units. The content of poly〇-phenylene sulfide is 80% by weight from the viewpoint of heat resistance and various mechanical properties of the film.
above, preferably 90% by weight or above, and poly-p
- The proportion of the above structural units in phenylene sulfide is 90
It is preferable that it is mol% or more.

The resin composition may contain inorganic or organic fillers, lubricants, ultraviolet absorbers, colorants, etc. in order to improve wear resistance and weather resistance, etc., to the extent that the properties of the polyphenylene sulfite film are not impaired. Can be done.

Polyphenylene sulfide film thickness is 0°4μm~
The average surface roughness Ra of the film is preferably in the range of 100 μm, and is preferably in the range of 0.03 to 0.10 μm, but is not limited to these ranges.

The polyphenylene sulfide film used in the present invention is
For example, it can be manufactured by the well-known method described in Japanese Patent Application Laid-Open No. 55-111235M.

The polyphenylene sulfide film of the present invention first has the following features:
It is important that the ratio of carbon atoms bonded to oxygen atoms to all carbon atoms on the surface is in the range of 3% to 20%, and secondly, the ratio of sulfuric acid, sulfonic acid ion, or sulfone to sulfur atoms is important. It is important that the proportion of sulfur atoms bonded to oxygen atoms in the form of an acid salt is in the range of 3% to 35%.

Here, the chemical bonding state of carbon and sulfur on the surface of the polyphenylene sulfide film can be determined by, for example, X-ray photoelectron spectroscopy (XPS) measurement. In other words, by irradiating the film surface with X-rays in XPS measurement and extracting the 1S peak of carbon and the 2P peak of sulfur from the emitted X-ray photoelectrons and performing peak splitting, we can determine the chemical bonding state of carbon-N and sulfur. You can find out how much of it is combined with

In the present invention, a carbon atom bonded to an oxygen atom means
When the C1S peak obtained by PS measurement was divided, -COO-
A carbon atom that belongs to the bonding state of 1=C=O1=C-0-.

On the surface of the polyphenylene sulfide film, if the number of carbon atoms bonded to oxygen atoms is less than 3% of all carbon atoms, sufficient thermal fusibility cannot be obtained, and if it exceeds 20%, it is still insufficient. This is not preferable because it is not possible to obtain good heat fusion properties, and the surface of the film becomes hard and brittle, resulting in a decrease in abrasion resistance.

More preferably, it is in the range of 4% to 15%.

In the present invention, sulfur atoms bonded to oxygen atoms in the form of sulfuric acid, sulfonic acid ions, or sulfuric acid salts are obtained by irradiating the film surface with X-rays in XPS measurement.
It refers to a sulfur atom that is assigned to the bonding state of 304 or SO3 when the 82p'-ri of emitted X-ray photoelectrons is extracted and peak-divided.

If the ratio of sulfur atoms bonded to 1M atoms in the form of sulfonic acid, sulfurate ion or sulfonate to sulfur atoms on the surface is less than 3%, thermal fusion properties may not be obtained; Although heat fusion properties can be obtained, there are disadvantages such as a decrease in releasability on the hot water side, which is not preferable. Further, if the above ratio exceeds 35%, sufficient heat fusion properties cannot be obtained.

A more preferable range of the ratio of sulfur atoms bonded to oxygen atoms in the form of sulfonic acid, sulfonate ions, or sulfonate to sulfur atoms is 4% to 30.
%.

One example of a method for producing such a polyphenylene sulfide film is to subject the surface or both sides of a polyphenylene sulfide film as a raw material to low-temperature plasma treatment, for example, in a selected mixed gas atmosphere and plasma conditions.

FIG. 1 illustrates an example of a low-temperature plasma processing apparatus that can be used in the present invention, and in the figure, a raw material film 1 is delivered to a discharge treatment section 9 by a delivery roll 2. A gas of a predetermined composition is supplied to the discharge treatment section 9 from a gas introduction system 8, and is maintained at a predetermined gas pressure by a simple exhaust device (not shown). The film 1 is subjected to high-voltage applied electricity 1f! in the discharge treatment section. 3 is processed by a high frequency high voltage applied via a matching transformer 6 from a high voltage power supply 5, and is processed by a discharge formed between it and a grounded drum-shaped electrode 4, and then wound onto a winding roll 7. .

Discharge is achieved by using a high voltage applying electrode whose surface is coated with a dielectric material such as rubber or glass on the surface of a conductor such as a metal tube that is cooled by flowing a coolant such as water inside, and a high voltage applying electrode that is provided opposite to the electrode. the surface on which the discharge is formed is covered with a similar dielectric,
It is formed between the electrode and the electrode for supporting the object to be processed. The thickness of the dielectric is preferably in the range of 0.1 to 5 mm.

It is not necessary to have the same number of high voltage application electrodes and electrodes that support the object to be processed; for each electrode that supports the object to be processed,
It is preferable to provide two or more high voltage application electrodes.

The frequency of the high voltage applied to the high voltage application electrode is preferably selected in the range of 50 KHz to 500 KHz.

In the present invention, gases suitably used for plasma processing include a mixed gas of an inert gas such as argon, krypton, or neon, oxygen and nitrogen, or a mixed gas of an inert gas and water vapor. It is important to select the appropriate mixing ratio. In the case of inert gas, nitrogen and oxygen: 99.8-75: 0.05-24:
It is best to select within the range of 0.05 to 24 (volume ratio).
In addition, in the case of a mixed gas of inert gas and water vapor, the volume ratio is 9
It is preferable to select each in the range of 9.8:0.2 to 75:25.

The pressure of the atmosphere is preferably selected in the range of 0.1 to 1000Torr, more preferably 10 to 900Torr.
It is best to select within the pressure range of rr.

As for the processing intensity, it is preferable to perform processing at a processing power density of 50 W-min/m2 or more, more preferably 10,100 W-min/m2 or more.
It is preferable to process the film at a processing power density of W-n/m2 or higher.The processing power density is the value obtained by dividing the output by the width of the discharge portion (in the axial direction of the drum-shaped electrode) and the processing speed of the film. be.

The polyphenylene sulfide film obtained by the present invention has strong thermal adhesive properties under normal conditions, and when it is desired to peel it off, it can be easily peeled off by supplying moisture to the bonded interface without damaging the bonded surface. Therefore, it can be effectively used in applications such as release films, protective films, labels, stickers, and tapes.

[Effects of the Invention] Since the polyphenylene sulfide film of the present invention has a surface with a specific chemical structure, it simultaneously has high thermal adhesion and wet releasability, and these properties do not deteriorate over time. This has the remarkable practical effect of not having to be used.

The reason for this effect is not clear, but carbon atoms bonded to oxygen atoms, such as >C=0, -
It is considered that polar groups such as COH1-COOI-1 are effective because they exhibit self-fusion properties. On the other hand, it is presumed that the presence of sulfur atoms bonded to oxygen atoms, such as sulfonic acid groups, causes the wet releasability.

[Example] Examples will be described below. Note that the following method was used to measure the characteristics in the present invention.

(1) Method for measuring the chemical structure of the surface of polyphenylene sulfide film X-ray photoelectron spectrometer (ESCA75 manufactured by Shimadzu Corporation)
0) to measure the 1S peak of carbon and the 2p peak of sulfur. Since this peak is necessary when synthesizing the peak of the chemically bonded state as shown below, it is decomposed into signals from the chemically bonded state using Gaussian component 45 approximation, and each chemical is determined from the peak height of each signal of the decomposition 1 wheat. Calculate the ratio of the number of atoms in a bonded state. In addition, the total number of carbon atoms or the total number of sulfur atoms is the sum of the ratios of the numbers of atoms in each of the following chemical bond states.

The C1S peak is π−π* −coo−=c=0,=C
-0-Neutral carbon, assigned to -C-S-.

*S2. The peaks are π-π, SOl, S03, -C-30
2-C--C-303-C--C-3O-C-1-C-
It is assigned to S-C-.

Here, 304, S Os represents sulfonic acid, sulfonic acid ion or sulftetraphosphate.

(2) Method for Measuring Adhesion Strength Two polyphenylene sulfide films were passed once between rolls heated to 220° C. with their treated surfaces not placed on top of each other to heat-seal them. 3KCI/Cm2 between rolls
The roll rotation speed was 1 m/min.

Next, the heat-sealed polyphenylene sulfide film was tested in a Schopper tensile tester (manufactured by Mahayana Kagaku Seiki Seisakusho).
The adhesive was set at 180 degrees and peeled off in a direction of 180 degrees, and the force required for peeling off was measured and determined as the dry adhesive strength. The peeling speed was 200 m/min.

Further, in the above method, peeling was performed while continuously supplying water, and the measured adhesive strength was defined as the welding strength.

Example 1.2 In the plasma processing apparatus of FIG.
μm polyphenylene sulfide film (Toshiku Co., Ltd.)
``TORELINA'') was set and processed.

Glass with a thickness of 1 mm is used as a dielectric material covering the electrode, and the distance between the high voltage application electrode and the drum-shaped electrode 4 is set to 1 mm.
It was set to

The inside of the discharge treatment section 9 is evacuated to below 1X10''Torr,
A mixed gas consisting of argon, nitrogen, and oxygen is introduced from the gas introduction system and maintained at 600 Torr. Next, a high frequency of 110 KHz was supplied from a high voltage power source 5 between the high voltage applying electrode 3 and the drum type (*4) to generate plasma.The input power was 1 KW in power output.

The treatment was carried out by passing the body through the generated plasma at a speed of 7 m/min (processing power density 240 W-min).
/m2).

The mixing ratio of argon:nitrogen:M element is 97.5:2:0.5
Example 1 is a case in which the mixing ratio is 90:8:2, and Example 2 is a case in which the mixing ratio is 90:8:2.

Table 1 shows the results of measuring the chemical structure of the surface of the obtained polyphenylene sulfide film. Further, the obtained polyphenylene sulfide film was left in a room open to the atmosphere for 6 months, and then the dry adhesion strength and welding strength were measured, and the results are shown in Table 2.

As is clear from Table 1.2, in the case of having the surface structure defined in the present invention, although it has extremely high soft adhesive strength, the continuous adhesive strength is extremely low. It can also be seen that these adhesive forces hardly change even after being left for a long period of time.

Table 1 XY soft adhesive strength Continuous adhesive strength (%) (%) (g/cm) l/cm) Example 1
56265'1 Example 27142722 Comparative Example 1 6 1 265 2f3B Comparative Example 2 1539 200 1 (Note) X: Ratio of carbon atoms bonded to oxygen atoms to total carbon atoms.

Y: Ratio of sulfur atoms bonded to oxygen atoms to sulfur atoms.

Table 2 Soft adhesive strength after 6 months of 1st decline in June Continuous adhesive strength (g/cm) l/cm) Example 1 270 1 Example 2 287 2 Comparative example 3 160 1 Comparative example 1.2 Argon gas was introduced Comparative Example 1 was obtained by performing the surface treatment in the same manner as in Example 1, except that the surface treatment was carried out in the same manner as in Example 1.

Also, the gas to be introduced is argon:nitrogen:oxygen in a ratio of 70:24.
Comparative Example 2 was obtained by surface treatment in the same manner as in Example 1 except that a mixed gas of :6 was used.

Table 1 shows the measurement results of the chemical structure of the surface of the jq-treated polyphenylene sulfide film. Table 2 shows the results of measuring soft adhesive strength and continuous adhesive strength after the obtained polyphenylene sulfide film was left in a room open to the atmosphere for 6 months.

As is clear from Table 1.2, in Comparative Example 1, although the soft adhesive strength was sufficiently large, the continuous adhesive strength was also very poor in wet peelability, which was disappointing. Furthermore, in the case of Comparative Example 2, although the continuous adhesive strength was extremely low, the soft adhesive strength was also low and was not practical.

Comparative example 3 The treatment was carried out using the corona discharge treatment apparatus shown in FIG.

In the figure, 11 is a delivery roll, 12 is a dielectric-covered drum-shaped electrode, 13 is an unwinding roll, ] 4 is a metal wire electrode, and the distance between both electrodes was set to 1 mm. The metal wire electrode is almost sealed by a cover 15 and a drum-shaped electrode, and air is introduced into this sealed space through a valve 16.
It was fed at a speed of 201/min. 110KHz for electrodes
A high-voltage power supply 17 was connected, and the input power was 1.2 KW in terms of power supply output, and a corona discharge was generated between the metal wire electrode and the drum-shaped electrode. The same polyphenylene sulfide film as in Example 1 was used as the substrate, and 20
The corona discharge treatment zone was run at a speed of m/min.

When the adhesive strength of one loaf of polyphenylene sulfide film was measured, the soft adhesive strength of the immediately treated wheat was 237q/c.
m, the continuous adhesive strength was 3 g/Cm, but the adhesive strength after being left for 6 months was a soft adhesive strength of 160 Q/Cm.

The continuous adhesive strength was 1 to 1/Cm, and the soft adhesive strength decreased significantly over time.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a plasma processing apparatus that can be used in the present invention, and FIG. 2 is a schematic diagram illustrating a corona discharge treatment apparatus used for producing a comparative example. 2.11 4.12

Claims (1)

[Claims] 1 On the surface, the ratio of carbon atoms bonded to oxygen atoms to all carbon atoms is in the range of 3% to 20%, and the ratio of carbon atoms bonded to oxygen atoms to all sulfur atoms is in the form of sulfonic acid, sulfonate ions, or sulfonate salts. A polyphenylene sulfide film characterized in that the proportion of bonded sulfur atoms is in the range of 3% to 35%.