JPH09221614A - Tacky adhesive composition, tacky adhesive tape or sheet produced by using the composition and tacky adhesive tape for binding wire harness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a tacky adhesive tape having improved sounddeadening performance and workability and producible in a continuous form. SOLUTION: A tacky adhesive layer 12 is formed by coating a surface of a substrate 11 made of a nonwoven cotton fabric with a tacky adhesive composition containing independent closed cells. The tacky adhesive composition is produced by using an elastomer as a base and compounding one or plural kinds of foaming agents capable of forming closed cells with heat to the base within a compounding range to enable the development of tacky adhesivity. A releasing agent layer 13 is formed on a surface of the substrate 11 opposite to the tacky adhesive layer 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive composition used for a wire harness binding adhesive tape used for binding a wire harness, a pressure-sensitive adhesive tape or sheet using the pressure-sensitive adhesive composition, and a wire harness binding adhesive. It's about tape.

[0002]

2. Description of the Related Art As an adhesive tape for binding a wire harness, an adhesive tape whose base material is mainly polyvinyl chloride has been used so far. In addition, from the viewpoint of improving the habitability of automobiles, an adhesive sheet made of a foamed material such as urethane foam is also used as a base material for the purpose of reducing noise such as tapping noise and frictional noise generated from a wire harness.

[0003]

When using an adhesive tape made of polyvinyl chloride as a base material when binding a wire harness, workability is good, but noise such as tapping noise and friction noise cannot be suppressed. . Further, when the pressure-sensitive adhesive sheet made of a foam such as urethane foam is used as the base material, the sound deadening property is good, but the length cannot be increased, and it is necessary to peel off the release paper due to the structure of the sheet. There was a problem that workability was poor. For these reasons, since the adhesive tape whose base material is polyvinyl chloride and the adhesive sheet whose base material is a foam such as urethane foam are used together, the cost is also high. In addition, when the adhesive tape based on cotton cloth or the adhesive tape based on acetate cloth disclosed in Japanese Utility Model Publication No. 4-643 is used, workability is good, but noise such as tapping noise and friction noise is completely eliminated. Can't hold back. As described above, in the related art, there is no wire harness binding adhesive tape that has excellent sound deadening properties, can be elongated, and has good workability.

The present invention has been made to solve the above-mentioned problems, and is used for an adhesive tape or sheet which is excellent in sound deadening property, can be elongated and has good workability, and the adhesive tape or sheet. It is an object of the present invention to provide a pressure-sensitive adhesive composition.

Another object of the present invention is to provide an adhesive tape for binding a wire harness, which is excellent in sound deadening property, can be made long, and has good workability for binding the wire harness.

[0006]

To achieve this object, in the present invention, one or more foaming agents are blended in an elastomer-based pressure-sensitive adhesive composition, and closed cells are generated by heating. To do.

In this case, a foaming agent which decomposes and foams at a temperature lower than the preparation temperature or processing temperature of the pressure-sensitive adhesive composition is used as the foaming agent.

A flame-retardant foaming agent is used as the foaming agent.

Further, in a pressure-sensitive adhesive composition based on an elastomer, a foam raw material and a foaming agent are blended to produce closed cells or a foam.

Further, in the pressure-sensitive adhesive composition based on an elastomer, one or more kinds of foaming resins are mixed and heated to form closed cells or foams.

In this case, a foamed resin that foams at a temperature lower than the temperature at which the pressure-sensitive adhesive composition is produced or processed is used as the foamed resin.

Further, in the pressure-sensitive adhesive composition based on elastomer, one or more kinds of hollow beads are blended.

In this case, the particle size of the hollow beads is made smaller than the thickness of the pressure-sensitive adhesive layer obtained by coating the pressure-sensitive adhesive composition on a substrate.

In a pressure-sensitive adhesive tape or sheet, the above-mentioned pressure-sensitive adhesive composition is coated on a substrate to form a pressure-sensitive adhesive layer.

In this case, a release agent layer is provided on the surface of the base material made of a non-woven fabric opposite to the surface on which the pressure-sensitive adhesive layer is provided.

Further, a resin layer is provided on the surface of the base material made of a non-woven fabric opposite to the surface on which the pressure-sensitive adhesive layer is provided.

In this case, a release agent layer is provided on the resin layer.

In the adhesive tape or sheet,
A pressure-sensitive adhesive layer is provided on one surface of a base material made of a non-woven fabric, and a release agent layer is provided on the surface of the base material opposite to the surface on which the pressure-sensitive adhesive layer is provided.

In the adhesive tape or sheet,
A pressure-sensitive adhesive layer is provided on one surface of a base material made of a non-woven fabric, and a resin layer is provided on the surface of the base material opposite to the surface on which the pressure-sensitive adhesive layer is provided.

In this case, a release agent layer is provided on the resin layer.

Further, in the wire harness binding adhesive tape, an adhesive layer is provided on one surface of a non-woven fabric substrate, and a resin layer is provided on the surface of the substrate opposite to the surface on which the adhesive layer is provided. Set up.

In this case, a release agent layer is provided on the resin layer.

In these cases, the resin layer is a polyolefin film layer.

In this case, the polyolefin film layer is a polyethylene film layer having a thickness of 10 to 35 μm.

Further, the above-mentioned base material has a thickness of 0.2 to 0.6 m.
m cotton non-woven fabric.

[0026]

1 is a schematic sectional view showing a part of an adhesive tape for binding a wire harness according to the present invention.
As shown in the figure, a pressure-sensitive adhesive layer 12 is provided by applying a pressure-sensitive adhesive composition having closed cells, in which each of the cells is independent and closed, on one surface of a substrate 11 made of a cotton nonwoven fabric, As this adhesive composition, an elastomer is used as a base, and one or more kinds of foaming agents which generate closed cells by heating are blended within a range capable of exhibiting adhesive performance. Further, a release agent layer 13 is provided on the surface of the base material 11 opposite to the surface on which the adhesive layer 12 is provided.

This wire harness binding adhesive tape,
In the pressure-sensitive adhesive composition, since closed cells are generated in the pressure-sensitive adhesive layer 12, it has cushioning properties, is excellent in sound deadening property, can be lengthened, and has good workability.
In addition, the amount of the pressure-sensitive adhesive composition used is reduced and the weight is reduced.
Further, since the base material 11 is made of cotton nonwoven fabric, the sound deadening property is very good. Further, since the release agent layer 13 is provided on the surface of the base material 11 opposite to the surface on which the adhesive layer 12 is provided, the base material for rewinding the rolled wire harness binding adhesive tape. 11 does not cause layer cracking, that is, the base material 11 of the lower adhesive tape is not rewound with the upper adhesive tape, and the adhesive tape can be easily unraveled, so that workability is further improved. is there.

FIG. 2 is a schematic sectional view showing a part of another adhesive tape for binding a wire harness according to the present invention. As shown in the figure, the resin layer 14 is provided on the surface of the base material 11 opposite to the surface on which the adhesive layer 12 is provided, and the release agent layer 15 is provided on the resin layer 14.

In this adhesive tape for binding wire harness, since the release agent layer 15 is provided on the surface of the base material 11 opposite to the surface on which the adhesive layer 12 is provided, it is easy to bind the wire harness. Workability is further improved because the adhesive tape can be unraveled. Further, since the release agent layer 15 is provided on the resin layer 14, the release agent layer 1
5 can be easily provided.

As the foaming agent of the pressure-sensitive adhesive composition used for the pressure-sensitive adhesive layer 12, n-propane, methyl chloride, azoisobutyronitrile, sodium bicarbonate, yeast, etc. can be used. If a foaming agent that decomposes and foams at a temperature lower than the preparation temperature or processing temperature of the pressure-sensitive adhesive composition is used as the foaming agent of the pressure-sensitive adhesive composition, the foaming step of heating at a particularly high temperature is not performed, Agent layer 12
It is possible to generate closed cells. In this case, a temperature lower than the temperature at the time of kneading the pressure-sensitive adhesive composition, preferably 70 to
A foaming agent that foams in the range of 140 ° C is preferred.

If a flame-retardant foaming agent is used as the foaming agent of the pressure-sensitive adhesive composition used for the pressure-sensitive adhesive layer 12, for example, when the pressure-sensitive adhesive tape is used for binding a wire harness of an automobile, it is applied to a high temperature part such as an engine room. can do.

If an adhesive composition is used in which the adhesive layer of the adhesive tape for binding wire harness is based on elastomer and the foam raw material and the foaming agent are blended to form closed cells or foam, Since the agent layer has larger closed cells or foam, the sound deadening property is very good, and the apparent specific gravity is small, so that the agent layer can be manufactured at a lower cost. As the foam raw material, urethane, acrylic, polyethylene or the like can be used.

Further, the adhesive layer of the adhesive tape for binding the wire harness is mixed with one or more kinds of foaming resin, which has an elastomer as a base and foams by itself, to produce closed cells or foam by heating. An adhesive composition may be used, and in this case, since a shearing force is easily applied in the kneading operation at the time of producing the adhesive composition, a high-performance adhesive tape for binding a wire harness can be obtained. As the foamed resin, hollow polyvinylidene chloride or the like can be used.

When the foamed resin is a foamed resin that foams at a temperature lower than the temperature at which the pressure-sensitive adhesive composition is produced or processed, closed cells are not formed in the pressure-sensitive adhesive layer without performing the foaming step of heating at a high temperature. Can be generated. In this case, a foamable resin that foams at a temperature lower than the temperature at the time of kneading the pressure-sensitive adhesive composition, preferably in the range of 70 to 140 ° C is preferable.

A pressure-sensitive adhesive composition having an elastomer as a base and one or more kinds of hollow beads mixed in the pressure-sensitive adhesive layer of the wire harness binding adhesive tape may be used. In this case, the apparent specific gravity is Becomes smaller,
Since it can be produced at a lower cost, and shearing force is easily applied during the kneading operation when producing the pressure-sensitive adhesive composition, a high-performance adhesive tape for binding a wire harness can be obtained. As the hollow beads, glass hollow beads, polyvinylidene chloride hollow beads and the like can be used.

Further, when the particle size of the hollow beads is made smaller than the thickness of the pressure-sensitive adhesive layer, the performance as a tape for adhesive strength and the like is good.

FIG. 3 is a schematic sectional view showing a part of another adhesive tape for binding a wire harness according to the present invention. As shown in the figure, a pressure-sensitive adhesive layer 22 having no closed cells or hollow beads is provided on one side of a base material 21 made of a cotton nonwoven fabric having a thickness of 0.2 to 0.6 mm. A release agent layer 23 is provided on the surface opposite to the surface provided with 22.

In this adhesive tape for binding wire harness, since the base material 21 is made of cotton non-woven fabric, it has a cushioning property, so that it is excellent in sound deadening property, can be lengthened, and has good workability. Further, since the thickness of the base material 21 is 0.2 mm or more, the sound deadening effect is sufficient, and since the thickness of the base material 21 is 0.6 mm or less, the length can be easily increased. , The size of the wire harness binding adhesive tape wrapped does not become extremely large. Moreover, since the release agent layer 23 is provided on the surface of the base material 21 opposite to the surface on which the adhesive layer 22 is provided, the adhesive tape can be easily unraveled, and workability is further improved. is there.

FIG. 4 is a schematic sectional view showing a part of another adhesive tape for binding a wire harness according to the present invention. As shown in the figure, a resin layer 24 made of a polyolefin film such as a polyethylene film having a thickness of 10 to 35 μm on the surface of the base material 21 opposite to the surface on which the adhesive layer 22 is provided.
And the release agent layer 25 is provided on the resin layer 24.

In this adhesive tape for binding wire harness, since the resin layer 24 is provided on the base material 21, the strength of the base material 21 is reinforced. Moreover, since the thickness of the resin layer 24 is 10 μm or more, the manufacturing is easy, and since the thickness of the resin layer 24 is 35 μm or less, the sound deadening property is not deteriorated. Further, since the release agent layer 25 is provided on the resin layer 24, the release agent layer 25 can be easily provided.

In the above embodiment, the adhesive tape for binding the wire harness has been described, but the present invention can be applied to other adhesive tapes and adhesive sheets. Further, in the above-described embodiment, the base materials 11 and 21 made of cotton non-woven fabric are used, but other non-woven fabric, cloth,
You may use the base material which consists of paper, a film, etc.

As described above, the pressure-sensitive adhesive composition according to the present invention is useful as a material for a pressure-sensitive adhesive layer of a wire harness binding adhesive tape, and the pressure-sensitive adhesive tape or sheet according to the present invention is used for wire harness binding. It is useful as a tape or sheet, and the adhesive tape for binding a wire harness according to the present invention is useful when it is mounted on an automobile.

[0043]

【Example】

(Example 1) Natural rubber 100 parts by weight, tackifying resin 10
A composition comprising 0 parts by weight, 150 parts by weight of calcium bicarbonate, 50 parts by weight of process oil, 2 parts by weight of an antioxidant and 50 parts by weight of a foamed resin was kneaded with a kneader to prepare an adhesive composition. Next, the base material 11 made of cotton non-woven fabric
The release agent layer 13 is provided on one surface of the base material 11, and the adhesive composition is applied to the other surface of the base material 11 so that the adhesive thickness is about 0.2 mm, and the adhesive layer 12 is provided to bind the wire harness. An adhesive tape was produced.

Comparative Example 1 A kneader was used by blending a composition comprising 100 parts by weight of natural rubber, 100 parts by weight of tackifying resin, 200 parts by weight of calcium bicarbonate, 50 parts by weight of process oil, and 2 parts by weight of antioxidant. The mixture was kneaded to prepare an adhesive composition. Next, a release agent layer is provided on one side of a base material made of cotton non-woven fabric, and the adhesive composition is applied on the other side of the base material so that the paste thickness is about 0.2 mm to form an adhesive layer. To produce a wire harness binding adhesive tape.

The physical properties of the adhesive tapes for binding the wire harness of Example 1 and Comparative Example 1 were evaluated. In this case, as a physical property evaluation method, the adhesive strength is JIS Z 0237.
Performed by That is, after a test piece having a width of 25 mm is crimped onto the test plate, the test piece is removed from the test plate at about 300
The average value of the forces when peeled at a speed of mm was taken as the adhesive force. The tacking was performed according to JIS Z 0237 (inclined ball tacking method, using balls having a diameter of 1/32 to 32/32 inch and indicated by a ball number). That is, the test piece was set with the adhesive surface facing upward on an inclined plate having an inclination angle of 30 degrees, and a polyester film for running was attached to a predetermined position on the adhesive surface of the test piece, and the running length was 100 m.
As m, balls of different sizes made of high carbon chrome bearing steel were rolled on the adhesive surface of the test piece, and the largest ball among the stopped balls was found in the measuring portion of 100 mm length of the adhesive surface of the test piece. . The ball number is a value obtained by multiplying the diameter of the ball by 32 times in inches. The holding power was measured according to JISZ0237. That is, the test piece was attached to the test plate so that the area of 25 × 25 mm was in contact, and 1 was applied to the end of the test piece at 40 ° C.
A weight of 000 gf was attached, and the time until the test piece dropped was measured. Further, the sound deadening property is obtained by sticking a sample adhesive tape on an iron plate, dropping a steel ball having a height of 100 mm to 100 g, measuring the sound pressure at that time, and dropping the steel ball on an empty iron plate. The value obtained by subtracting the above sound pressure from the sound pressure was calculated. In this case, the larger the difference in sound pressure between when dropped on an empty iron plate, the better the sound deadening effect. Table 1 collectively shows the results of evaluation of physical properties of the adhesive tapes for binding wire harnesses of Example 1 and Comparative Example 1.

[0046]

[Table 1]

As is clear from Table 1, by adding the foaming resin to the pressure-sensitive adhesive composition, the sound deadening property could be improved without affecting the adhesive property.

Example 2 A resin layer 24 made of polyethylene film and having a thickness of 15 μm is provided on one surface of a base material 21 made of cotton non-woven fabric having a thickness of 0.2 mm.
4, a release agent layer 25 is provided on the base 4, and a natural rubber-based pressure-sensitive adhesive layer 22 is applied to the surface of the base material 21 opposite to the surface on which the resin layer 24 is laminated so as to have a thickness of 0.2 mm. An adhesive tape for binding a wire harness was produced.

This wire harness binding adhesive tape can be lengthened to 300 m or more, and when rewound,
The base material 21 did not undergo layer breakage.

(Comparative Example 2) A natural rubber-based pressure-sensitive adhesive layer was applied to a base material made of cotton cloth having a thickness of 0.3 mm to a thickness of 0.2 mm to prepare a wire harness binding adhesive tape.

The wire harness binding adhesive tapes of Example 2 and Comparative Example 2 were wrapped around the wire harness in a half-wrapped state and bound to form test samples a and b.
Further, the wire harness of Comparative Example 2 which was not bundled was used as the test sample c, and the sound deadening properties of the test samples a to c were evaluated. In this evaluation method, a part of the test samples a to c is fixed to an iron plate with a commercially available band used for bundling electric wires, and the iron plate is heated to 10H.
It is a method of vibrating at frequencies of z, 30 Hz, and 50 Hz, and measuring the sound when the test samples a to c hit the iron plate with a sound level meter. The result of evaluation of this sound deadening property is shown in FIG. FIG.
As is clear from the above, the wire harness binding adhesive tape of Example 2 has excellent noise prevention performance.

[0052]

INDUSTRIAL APPLICABILITY In the pressure-sensitive adhesive composition according to the present invention, the pressure-sensitive adhesive tape or sheet using the pressure-sensitive adhesive composition, and the wire-harness binding pressure-sensitive adhesive tape, closed cells or foams are formed in the pressure-sensitive adhesive layer, so that the cushioning property is improved. Since it has, it has excellent sound deadening properties, can be made longer, and has good workability.

When a foaming agent which decomposes and foams at a temperature lower than the preparation temperature or processing temperature of the pressure-sensitive adhesive composition is used as the foaming agent, the pressure-sensitive adhesive composition is not subjected to the foaming step of heating at a particularly high temperature. Closed bubbles can be generated in an object.

When a flame-retardant foaming agent is used as the foaming agent, it can be applied to high-temperature locations.

In addition, when a foam raw material and a foaming agent are blended to form a closed cell or a foam in a pressure-sensitive adhesive composition based on an elastomer, the pressure-sensitive adhesive composition produces a larger closed cell or foam. Since it has, the sound deadening property is very good, and the apparent specific gravity is small, so that it can be manufactured at a lower cost.

In an elastomer-based pressure-sensitive adhesive composition, when one or more types of foaming resin are blended to form closed cells or foams by heating, the kneading operation in preparing the pressure-sensitive adhesive composition is performed. Since a shearing force is easily applied, a high-performance pressure-sensitive adhesive composition can be obtained.

When a foamed resin that foams at a temperature lower than the temperature at which the pressure-sensitive adhesive composition is produced or processed is used as the foamed resin, the pressure-sensitive adhesive composition can be used independently without the foaming step of heating at a high temperature. Bubbles can be generated.

In addition, in the pressure-sensitive adhesive composition based on an elastomer, when one or more kinds of hollow beads are blended, the apparent specific gravity becomes small, so that the pressure-sensitive adhesive composition can be produced more inexpensively, and the pressure-sensitive adhesive composition Since a shearing force is easily applied in the kneading operation at the time of producing a product, a high-performance pressure-sensitive adhesive composition can be obtained.

Further, when the particle diameter of the hollow beads is made smaller than the thickness of the pressure-sensitive adhesive layer obtained by coating the pressure-sensitive adhesive composition on the substrate, the tape has good performance such as adhesive strength.

When a release agent layer is provided on the surface of the base material made of non-woven fabric opposite to the surface provided with the adhesive layer, the sound absorbing property is very good and the adhesive tape is easily unraveled. Therefore, the workability is good.

When a resin layer is provided on the surface of the non-woven fabric substrate opposite to the surface on which the adhesive layer is provided,
The strength of the base material can be reinforced.

When the release agent layer is provided on the resin layer, the release agent layer can be easily provided.

When the resin layer is a polyethylene film layer having a thickness of 10 to 35 μm, the production is easy and the sound deadening property is not deteriorated.

When the base material is a cotton non-woven fabric having a thickness of 0.2 to 0.6 mm, the sound deadening effect is sufficient, the length can be easily increased, and the wire harness binding adhesive tape is wound. The size of the existing state does not become extremely large.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a part of an adhesive tape for binding a wire harness according to the present invention.

FIG. 2 is a schematic cross-sectional view showing a part of another adhesive tape for binding a wire harness according to the present invention.

FIG. 3 is a schematic sectional view showing a part of another wire harness binding adhesive tape according to the present invention.

FIG. 4 is a schematic cross-sectional view showing a part of another wire harness binding adhesive tape according to the present invention.

FIG. 5 is a graph showing evaluation results of sound deadening properties of the adhesive tape for binding a wire harness according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Base material 12 ... Adhesive layer 13 ... Release agent layer 14 ... Resin layer 15 ... Release agent layer 21 ... Base material 22 ... Adhesive layer 23 ... Release agent layer 24 ... Resin layer 25 ... Release agent layer

Claims (20)

[Claims] 1. A pressure-sensitive adhesive composition comprising an elastomer-based pressure-sensitive adhesive composition, wherein one or more types of foaming agents are mixed and closed cells are generated by heating. 2. The pressure-sensitive adhesive composition according to claim 1, wherein the foaming agent is a foaming agent that decomposes and foams at a temperature lower than the preparation temperature or the processing temperature of the pressure-sensitive adhesive composition. 3. The pressure-sensitive adhesive composition according to claim 1, wherein the foaming agent is a flame-retardant foaming agent. 4. A pressure-sensitive adhesive composition comprising an elastomer-based pressure-sensitive adhesive composition, wherein a foam raw material and a foaming agent are blended to form closed cells or a foam. 5. A pressure-sensitive adhesive composition comprising an elastomer-based pressure-sensitive adhesive composition, wherein one or more types of foaming resins are blended, and closed cells or foams are produced by heating. 6. The pressure-sensitive adhesive composition according to claim 5, wherein the foamed resin is a foamed resin that foams at a temperature lower than a temperature at which the pressure-sensitive adhesive composition is produced or processed. 7. An adhesive composition containing an elastomer as a base, wherein one or more kinds of hollow beads are mixed. 8. The pressure-sensitive adhesive composition according to claim 7, wherein the particle size of the hollow beads is smaller than the thickness of the pressure-sensitive adhesive layer formed by coating the pressure-sensitive adhesive composition on a substrate. 9. A pressure-sensitive adhesive tape or sheet comprising a base material coated with the pressure-sensitive adhesive composition according to claim 1, 4, 5 or 7 to form a pressure-sensitive adhesive layer. 10. The substrate according to claim 9, wherein the substrate is made of a non-woven fabric, and a release agent layer is provided on the surface of the substrate opposite to the surface provided with the pressure-sensitive adhesive layer. Adhesive tape or sheet. 11. The pressure-sensitive adhesive according to claim 9, wherein the base material is made of a non-woven fabric, and a resin layer is provided on a surface of the base material opposite to a surface on which the pressure-sensitive adhesive layer is provided. Tape or sheet. 12. The pressure-sensitive adhesive tape or sheet according to claim 11, wherein a release agent layer is provided on the resin layer. 13. A non-woven fabric substrate is provided with an adhesive layer on one side thereof, and a release agent layer is provided on a face of the substrate opposite to the face provided with the adhesive layer. Adhesive tape or sheet. 14. An adhesive characterized in that a pressure-sensitive adhesive layer is provided on one surface of a base material made of a non-woven fabric, and a resin layer is provided on a surface opposite to the surface of the base material on which the pressure-sensitive adhesive layer is provided. Tape or sheet. 15. The pressure-sensitive adhesive tape or sheet according to claim 14, wherein a release agent layer is provided on the resin layer. 16. A wire characterized in that a pressure-sensitive adhesive layer is provided on one surface of a base material made of a non-woven fabric, and a resin layer is provided on a surface opposite to the surface of the base material on which the pressure-sensitive adhesive layer is provided. Adhesive tape for binding harnesses. 17. The adhesive tape for binding a wire harness according to claim 16, wherein a release agent layer is provided on the resin layer. 18. The adhesive tape for binding a wire harness according to claim 16 or 17, wherein the resin layer is a polyolefin film layer. 19. The adhesive tape for binding a wire harness according to claim 18, wherein the polyolefin film layer is a polyethylene film layer having a thickness of 10 to 35 μm. 20. The adhesive tape for binding a wire harness according to claim 16, wherein the base material is a cotton nonwoven fabric having a thickness of 0.2 to 0.6 mm.