JP2007106816A - Method for producing uniaxially drawn microporous tetrafluoroethylene film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a uniaxially drawn microporous tetrafluoroethylene film having improved uniformity of the distribution of micropores, pore diameter and void ratio, increased air permeability and moisture permeability and improved waterproofing effect with a simplified production process at increased production speed. <P>SOLUTION: An intermediate product comprising a rolled sheet of tetrafluoroethylene is used as a principal raw material. The rolled sheet is taken up from a raw material delivery roll and introduced in a drawing stage through a roller. The drawing stage is a step to transfer the intermediate product from the first drawing roll to the fourth drawing roll. The intermediate product is heated with the first heating apparatus in the drawing stage as a temporary forming step, transferred to the second heating apparatus as a forming step after the drawing stage, and wound on a winding roll as the final product to obtain the uniaxially drawn microporous tetrafluoroethylene film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a method for producing a microporous tetrafluoroethylene film, in particular, the production method is simplified and the production rate is improved, and the distribution of fine holes, hole diameter, and clearance ratio in the film are reduced. The present invention relates to a method for producing a uniaxially stretched microporous tetrafluoroethylene film that is uniform, has high air permeability and moisture permeability, and improves the waterproofing effect.

The well-known Teflon (registered trademark) is a resin, the chemical name is tetrafluoroethylene, and it is formed by polymerizing tetrafluoroethylene (C ₂ F ₄ ). It is composed of and does not react with oxygen, so it does not react with oxygen, so it has characteristics such as heat resistance, low temperature resistance, corrosion resistance, non-adhesiveness, low coefficient of friction and self-lubricity, Trademark) is one of the materials that are often used because it is difficult to melt with other substances.

Because tetrafluoroethylene has the above properties, some manufacturers process tetrafluoroethylene into a porous sheet or film and laminate it into a woven or non-woven fabric for use as a filtering material or other material. For example, US Pat. No. 5,347,739, US Pat. No. 6,080,472, US Pat. No. 5,750,242, Taiwan Patent No. 538164, and Taiwan Patent No. 592783 were proposed.

So processed tetrafluoroethylene is widely applied in industry and consumer products, and its manufacturing process depends on the field to be used, such as US Pat. Nos. 6,670,971, 6,852,223, 5098625, No. 6228477, No. 6410084, No. 6667993, No. 6854603, No. 4096227 were proposed.

As is apparent from the above patent, all tetrafluoroethylene sheets or films are porous. In these sheets or films, the uniformity of the fine hole distribution and the hole diameter could not be controlled within a certain range.
U.S. Patent No. 5,347,739, U.S. Patent No. 6080472, U.S. Patent No. 5,750,242, Taiwan Patent No. 538164, Taiwan Patent No. 592783 U.S. Pat.Nos. 6,670,971, 6,852,223, 5098625, 6,228477, 641,0084, 6,667,993, 6,854,603, 4096227

However, this has the following drawbacks.
(A) In these sheets or films, the uniformity of the fine hole distribution and the hole diameter could not be controlled within a certain range.

(B) In order to control the distribution of the fine holes and the uniformity of the hole diameters within a certain range, it is necessary to increase production facilities, resulting in an increase in production cost.

(C) The above production process is extremely complicated, and if the production process is not properly managed, a large number of defective products are generated, and quality control is difficult to perform.

Main object of the present invention is a method for producing a uniaxial tensile microporous tetrafluoroethylene film that facilitates quality control, improves productivity, reduces yield, and reduces production costs I will provide a.

The next object of the present invention is to provide a uniaxial tensile microporous tetrafluoroethylene film in which the uniformity of the fine hole distribution and hole diameter in the sheet or film can be controlled within a certain range. A manufacturing method is provided.

Another object of the present invention is to provide a method for producing a uniaxially stretched microporous tetrafluoroethylene film that has high air permeability and moisture permeability and improves the waterproof effect.

The invention of the present application made to achieve the above object is based on a work in progress, which is a rolled sheet of tetrafluoroethylene, as a basic raw material, and the work in progress is drawn from a raw material charging roll and enters a pulling process via a roller. The pulling process is a process of transporting the work in progress from the first pulling roll to the fourth pulling roll. During the pulling process, heating is performed by the first heating device, which is assumed to be a hypothetical process. It is transported to a second heating device, which is used as a standard process, and finally, the finished product is wound up on a winding roll, and is a method for producing a uniaxial tensile microporous tetrafluoroethylene film. Is the gist.

In the invention of the present application, the tension process includes a first-stage tension and a second-stage tension, and the in-process goods are transported between the first and second tension rolls as the first-stage tension, Is transported between the third tension roll and the fourth tension roll as a second stage tension, and a hypothetical process may be performed during or before the second stage tension process. The gist of the present invention is the method for producing a uniaxially stretched microporous tetrafluoroethylene film according to claim 1.

In the invention of the present application, including the first stage tension, the hypothetical form and the second stage tension, the total elongation ratio is 6 to 12 times, the first stage tension performs the longitudinal tension, the second stage tension is The heating of the hypothetical process and the tension in the width direction are performed during or before the tension process, and the elongation amount of the second stage tension is larger than that of the first stage tension. Pulling process controlled to 80-150 ° C, overheating time controlled to 3-5 seconds, shaping process, heating temperature controlled to 300-400 ° C, overheating time controlled to 10 seconds, and winding process In a method for producing a uniaxially tensioned microporous tetrafluoroethylene film containing a tetrafluoroethylene film as a work-in-process (thickness 0.10 to 0.15 mm, width 160 to 300)
mm, specific gravity 0.8 to 1.3 g / cm ³ , with no fine holes on the surface), which has been subjected to corona discharge treatment, and the finished product is a uniaxial tensile microporous tetrafluoroethylene film with a thickness of It is controlled to 0.03~0.06mm by required, a width of 1600 mm, a gap ratio of 80~85%, JIS L-1092 water圧度obtained by the test method be 9000 mm-H ₂ O or , JIS
The gist is that it is a method for producing a uniaxially tensile microporous tetrafluoroethylene film characterized in that the degree of water bleeding obtained by the L-1099A1 test method is 9995 to 11713 g / M ² * 24 hrs .

In the invention of the present application, the elongation ratio between the elongation amount of the first stage tension and the elongation amount before the first stage tension is 1.5 times, the elongation amount of the second stage tension, the elongation amount of the first stage tension, The gist of the present invention is the method for producing a uniaxially stretched microporous tetrafluoroethylene film according to claim 3, wherein the elongation ratio is from 4 to 8 times.

In the invention of the present application, ASTM E-96 may be adopted as the water bleeding test method, and the data obtained by the ASTM E-96 test method is 13045-15445 g / M ² * 24 hrs. The gist of the present invention is the process for producing a uniaxially stretched microporous tetrafluoroethylene film according to claim 3.

In the invention of the present application, other known test methods may be adopted as a test method for water pressure resistance and water bleed degree. The gist is that it is a method for producing a fluoroethylene film.

The method for producing a uniaxially stretched microporous tetrafluoroethylene film according to the present invention has the following effects.
(A) Quality control is facilitated, productivity is improved, yield is reduced, and production costs are reduced.

(B) The uniformity of the fine hole distribution and the hole diameter in the sheet or film can be controlled within a certain range.

(C) Air permeability and moisture permeability are increased, and the waterproof effect is improved.

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

First, the characteristics of a Teflon (registered trademark) biaxial tensile film are analyzed. Teflon (registered trademark) uses ultra-high molecular weight tetrafluoroethylene as a main raw material, and a biaxially stretched film is produced by special processing. When this film is observed with a high-power electron microscope, fibers and nodes are extremely The fibers and nodes that are crisp and treated at different temperatures and elongations are different, and the higher magnification tension is not pulling the existing fibers, but the nodes between the existing fibers are not This means that the film splits into finer fibers or becomes smaller nodes, and the above split makes the film with micron class or nano class fibers, and these films can be applied to products and components in various fields. ing.

The emphasis of the present invention is on the tensioning process and temperature control.According to the present invention, quality control is facilitated, productivity is improved, yield is reduced, production cost is reduced, sheet or The uniformity of the fine hole distribution and the hole diameter in the film can be controlled within a certain range, and the air permeability and moisture permeability are increased, thereby improving the waterproof effect.

FIG. 1 is a flowchart showing a production process according to the present invention. In the production process, the work-in-process 10 becomes a finished product 50 through a pulling process 20 and a fixed shape 30, and the finished product 50 is wound up and shipped.

FIG. 2 is a schematic view showing an embodiment of a production process according to the present invention. The work in progress 10 which is a rolled sheet of tetrafluoroethylene is used as a basic raw material, and the work in progress 10 is drawn from a raw material charging roll 10 'and enters a pulling step 20 through rollers 11', 12 'and 13'. The tensioning process 20 includes a first-stage tension 21, a second-stage tension 22, and a hypothetical form 23 to indicate that the work in process 10 is transported between the first tension roll 14 'and the second tension roll 16'. The first-stage tension 21 is defined between the rollers 11 ′, 12 ′, 13 ′, the first tension roll 14 ′, and the second tension roll 16 ′ when the work-in-process 10 is pulled. Is to adjust the supply amount of the tetrafluoroethylene rolled sheet as the work-in-process 10 and to apply a tensile force in the longitudinal direction. One step The elongation ratio with respect to the amount of elongation before the tension 21 is 1.5 times, and the second stage tension 22 indicates that the work in progress 10 is transported between the third tension roll 17 'and the fourth tension roll 18'. And an assumption form 23 heated by the first heating device 19 'is implemented during or before the second stage tension, and the elongation of the second stage tension 22 performed while heating, and the first stage tension The elongation ratio with respect to the elongation amount is 4 to 8 times, and since the elongation ratio is larger, it is necessary to heat during or before the process of the hypothetical shape 23, and then the elongation amount of the second stage tension 22 And the ductility and malleability of the film can be improved, and it can be prevented that the film is torn during the pulling process or the distribution of fine holes in the film, the hole diameter and the gap ratio are not uniform. First stage tension 21 and second stage The combination of the tension 22 and the hypothetical shape 23 is referred to as a tensioning process 20, and the total elongation ratio of the tensioning process 20 is 6 to 12 times. After the tensioning process 20, the work in process 10 is transported to the second heating device 20 ′. This is defined as a regular process 30, and the regular process 30 is heated by the second heating device 20 ′ so that the distribution of fine holes in the film, the hole diameter, and the gap ratio are made uniform and fixed. The phenomenon that the film returns and shrinks can be prevented, and finally, the finished product 50 is wound around a winding roll and shipped.

The manufacturing method of the uniaxial tension microporous tetrafluoroethylene film includes the first stage tension, the hypothetical form and the second stage tension, the total elongation ratio is 6 to 12 times, and the first stage tension is longitudinal. In the second stage tension, the heating of the hypothetical process and the tension in the width direction are performed during or before the tension process, and the elongation of the second stage tension is higher than that of the first stage tension. The hypothetical process is a tension process in which the heating temperature is controlled to 80 to 150 ° C. and the overheating time is controlled to 3 to 5 seconds,

A regular process in which the heating temperature is controlled to 300 to 400 ° C. and the overheating time is controlled to 10 seconds,

Winding process,

The work-in-process tetrafluoroethylene film (thickness 0.10 to 0.15 mm, width 160 to 300 mm, specific gravity 0.8 to 1.3 g / cm ³ , and no fine holes on the surface) has been subjected to corona discharge treatment,

The finished product is a uniaxial tensile microporous tetrafluoroethylene film, the thickness of which is controlled to 0.03 to 0.06 mm as required, the width is 1600 mm, the gap ratio is 80 to 85%, JIS Water pressure resistance obtained by L-1092 test method is 9000MM-H ₂ O or more, JIS
The degree of water bleeding obtained by the L-1099A1 test method is 9995 to 11713 g / M ² * 24 hrs.

FIG. 3 is a micrograph of the work-in-process 10 of the present invention, in which the distribution of fibers is seen, and FIG. 4 is a microphotograph of the finished product 50 of the present invention, in which the distribution of fibers and nodes is clearly seen. The main differences from the work-in-process 10 are the uniformity of the gap ratio, the hole diameter and the hole distribution generated during the connection between the fiber and the node, and the uniformity of the fiber and node distribution.

FIG. 5 is a graph showing a melting curve of the work-in-process 10 of the present invention. As is clear from the drawing, when the heating is continued from 50 ° C. to 350 ° C., an endothermic peak of 344.89 ° C. is obtained, and FIG. As shown in the drawing, when the heating is continued from 50 ° C. to 350 ° C., an endothermic peak of 336.51 ° C. is obtained. The difference between the numerical value of the endothermic peak is extremely small, that is, the difference between the melting curves of the finished product 50 processed by the manufacturing method according to the present invention and the work-in-process 10 is within a certain range, and the numerical value of the endothermic peak before and after processing. Does not change much.

Further, FIG. 7 shows a data table obtained by testing the water bleeding degree of the present invention. The water bleeding degree obtained by the JIS L-1099A1 test method is 9995 to 11713 g / M ² * 24 hrs, and ASTM E- The data obtained with the 96 test method is 13045-15445g / M ² * 24hrs, which is higher than the water bleed of conventional films, so the finished product is a microporous tetrafluoroethylene with high water bleed.・ It turns out to be a film.

It is a flowchart which shows the production process which concerns on this invention. It is the schematic which shows the Example of the production process which concerns on this invention. It is a microphotograph of the work-in-process of this invention. It is a microphotograph of the finished product of the present invention. It is a graph which shows the melting curve of the work in process of this invention. It is a graph which shows the melting curve of the finished product of this invention. It is the data table which tested the water bleeding degree of this invention.

Explanation of symbols

10 Work in process 20 Tension process 21 First stage tension 22 Second stage tension 23 Assumed form 30 Standard form 40 Winding 50 Finished product 10 'Raw material feeding rolls 11', 12 ', 13' Roller 14 'First tension roll 15' Roller 16 'second tension roll 17' third tension roll 18 'fourth tension roll 19' first heating device 20 'second heating device 21' take-up roll

Claims (6)

The work in progress, which is a rolled sheet of tetrafluoroethylene, is used as a basic raw material, and the work in progress is drawn from the raw material charging roll and enters a pulling process via a roller. It is a process of transporting to the four pulling rolls. During the pulling process, it is heated by the first heating device, this is assumed as the process, and after the pulling process, the work in process is transported to the second heating apparatus, which is defined as the regular process, Finally, a method for producing a uniaxial tensile microporous tetrafluoroethylene film, wherein the finished product is wound on a winding roll. The tension process includes a first-stage tension and a second-stage tension. The work in progress is transported between the first tension roll and the second tension roll, and the work in progress is a third tension roll. The second stage tension is transported between the first tension roll and the fourth tension roll, and a hypothetical process may be performed during or before the second stage tension. A method for producing a uniaxially stretched microporous tetrafluoroethylene film according to claim 1. Including the first stage tension, hypothetical form and second stage tension, the total elongation ratio is 6-12 times, the first stage tension performs the longitudinal tension, the second stage tension is in the process of tension Alternatively, the heating of the hypothetical process and the tensile in the width direction are performed before, and the elongation amount of the second stage tension is larger than that of the first stage tension. A tensioning process that is controlled and the overheating time is controlled to 3-5 seconds;
A regular process in which the heating temperature is controlled to 300 to 400 ° C. and the overheating time is controlled to 10 seconds,
In the manufacturing method of the uniaxial tension microporous tetrafluoroethylene film including a winding process,
The work-in-process tetrafluoroethylene film (thickness 0.10 to 0.15 mm, width 160 to 300 mm, specific gravity 0.8 to 1.3 g / cm ³ , and no fine holes on the surface) has been subjected to corona discharge treatment,
The finished product is a uniaxial tensile microporous tetrafluoroethylene film, the thickness of which is controlled to 0.03 to 0.06 mm as required, the width is 1600 mm, the gap ratio is 80 to 85%, JIS Water pressure resistance obtained by L-1092 test method is 9000MM-H ₂ O or more, JIS
The water bleeding degree obtained by the L-1099A1 test method is 9995 to 11713 g / M ² * 24 hrs,
Method for producing uniaxially stretched microporous tetrafluoroethylene film. The elongation ratio between the elongation amount of the first stage tension and the elongation amount before the first stage tension is 1.5 times, and the elongation ratio between the elongation amount of the second stage tension and the elongation amount of the first stage tension is 4 times. The method for producing a uniaxially stretched microporous tetrafluoroethylene film according to claim 3, wherein the production method is ˜8 times. The water bleeding test method may adopt ASTM E-96, and the data obtained by the ASTM E-96 test method is 13045-15445g / M ² * 24hrs. The manufacturing method of the uniaxial tension microporous tetrafluoroethylene film of description. The uniaxial tensile microporous tetrafluoroethylene ··· according to claim 3 or 5, characterized in that other known test methods may be adopted as a test method for water pressure resistance and water bleeding. A method for producing a film.