KR20110046473A - Manufacturing method of soft sheet - Google Patents

Abstract

An object of the present invention is to provide a method for producing an efficient soft sheet, particularly a method for producing a soft sheet having a shortened rolling process, and to prepare a die having a mixture, which is a raw material of the soft sheet, and a cross-sectional hole through which the mixture passes. An extrusion step of forming a long object by passing the mixture through a cross-sectional hole of the die, a cutting step of cutting a long item formed by the extrusion step to obtain a predetermined cut object, and a predetermined cut obtained by the cutting step A rolling process of rolling water to form a sheet having a uniform property, wherein the material of the mixture is a composition in which an inorganic filler is mixed with a fluororesin, and the cross-sectional shape of the long product formed by the extrusion process is annular. The manufacturing method of the soft sheet.

Description

Method for producing soft sheet {Method for producing soft sheet}

The present invention relates to a method for producing soft sheets such as sheet gaskets, and more particularly, to a method for producing soft sheets having uniform properties obtained by cutting and rolling a mixture extruded by an extruder.

The filler-containing fluororesin sheet is obtained by filling a fluorine resin with a filler and processing it into a sheet. In addition to the chemical resistance, heat resistance, non-adhesiveness, and low friction properties of the fluorine resin, Or it improves abrasion resistance and large creep resistance which are a fault of a fluororesin, and is used a lot in a seal material.

As a manufacturing method of the soft sheet represented by this filler containing fluororesin sheet, after stirring and mixing a material, and heating this, the mixture obtained is extruded to flat form with an extruder, and it cuts, rolls, and forms it into a sheet form. Is adopted.

4 and 5 are explanatory views of the manufacturing method of the soft sheet of the prior art. FIG. 4 shows an extrusion process in which the material 110 is extruded as the flat long material 120 by the extruder 100, and FIG. 5 is cut and rolled the continuous flat long material 120 to produce a soft material. The process of molding the sheet 130 is shown.

As shown in FIG. 4, the material 110 introduced from the hopper 104 is integrated by being heated and pressurized in the cylinder 108. The integrated material 110 is extruded in the direction of the tip of the extruder 100 and passes through the die 102 provided at the tip. The die 102 is a so-called flat die which extrudes a mixture, i.e., the mixed material 110, into a flat plate, and the mixture passes through the cross-sectional hole 102a of the die 102, thereby making continuous flat elongation. Water 120 is extruded.

Next, the continuous flat elongate 120 shape | molded by the extruder 100 is cut | disconnected to predetermined dimension by the cutting process shown in FIG. 5 (A), and The cut 122 is obtained. Then, after the cuts 122 are folded and overlapped by the rolling step shown in FIG. 5 (B), they are repeatedly rolled until a predetermined thickness is obtained. At this time, rolling after cutting the cut 122 is necessary to remove the voids and to orient the molecular chain to give strength, that is, to promote the fiberization of the fluororesin, a large number of times of rolling Because. In addition, as shown to FIG. 5 (C), the sheet edge part 124 which dry-deteriorated by cut rolling is cut | disconnected, and after that, it goes through each process of drying, baking, correction, etc. which are not shown in figure, The soft sheet 130 as shown in 5 (D) is manufactured.

By the way, in the said shaping | molding method, since a rolling process occupies a big specific gravity among the manufacturing processes of a soft sheet, it is a subject how to shorten this rolling process in order to make the manufacturing process of a soft sheet efficient.

This invention is made | formed in view of the said subject, and an object of this invention is to provide the manufacturing method of the soft sheet which is more efficient than before, and has a uniform property.

The present invention has been invented in order to achieve the problems and objects in the prior art as described above, the manufacturing method of the soft sheet of the present invention,

An extrusion step of preparing a die having a mixture which is a raw material of the soft sheet and a cross section hole through which the mixture passes, and passing the mixture through a cross section hole of the die, thereby forming a long object;

A cutting step of cutting the long articles formed by the extrusion step to obtain a predetermined cut piece;

It has a rolling process of shape | molding the sheet of a uniform shape by rolling the predetermined | prescribed cut object obtained by the said cutting process,

As a material of the said mixture which mix | blended an inorganic filler with a fluororesin,

The cross-sectional shape of the long product formed by the extrusion process is characterized by an annular shape.

By constructing the present invention as described above, it is possible to promote the fiberization of the fluorine resin in the extrusion step by increasing the extrusion ratio in the extrusion step, so that the number of rolling in the rolling step can be reduced. In addition, the yield is also improved, and it becomes possible to manufacture the soft sheet more efficiently than before.

Moreover, in the said invention, it is preferable that the said fluororesin is polyterafluoroethylene resin.

By constructing the present invention as described above, the effect of the present invention that a soft sheet having a uniform property can be produced with a small number of rollings is remarkably exhibited.

Moreover, in the said invention, it is preferable that the ratio of the inorganic filler to the material of the said mixture is 20 weight% or more.

By constructing the present invention as described above, the effect of the present invention that a soft sheet having a uniform property can be produced with a small number of rollings is more remarkably exhibited.

Moreover, in the said invention, it is preferable that the extrusion ratio in the said extrusion process is 5-10.

By constructing the present invention as described above, the efficiency in the extrusion process is not deteriorated, and it becomes possible to manufacture the soft sheet more efficiently than conventionally with a small number of rolling.

According to the method for producing a soft sheet of the present invention, since the fiberization of the fluororesin in the extrusion step can be promoted by increasing the extrusion ratio in the extrusion step, the rolling step can be shorter than before. In addition, the yield is also improved, and it becomes possible to manufacture a soft sheet having a uniform property more efficiently than in the past.

1 is a view showing an extrusion process as a method of manufacturing a soft sheet of the present invention.
2 is a view showing a process of forming a soft sheet by cutting and rolling as a method for producing a soft sheet of the present invention.
3 is a view showing a cross-sectional shape of another long object of the present invention.
4 is a view showing an extrusion process as a method of manufacturing a soft sheet of the prior art.
5 is a view showing a process of forming a soft sheet by cutting and rolling as a method of manufacturing a soft sheet of the prior art.

EMBODIMENT OF THE INVENTION Hereinafter, although this invention is demonstrated referring drawings, this invention is not limited to these embodiment at all.

1 and 2 are explanatory views of a method for producing a soft sheet of the present invention. FIG. 1 shows an extrusion process in which the material 10 is extruded as an annular long product 20 by the extruder 1, and FIG. 2 shows a continuous annular long product 20. The process of cutting | drilling and rolling and shape | molding the soft sheet | seat 30 is shown.

As shown in FIG. 1, the material 10 injected from the hopper 4 is heated in the cylinder 8 to be in a mixed state. As the material 10, it is preferable that it is a composition which mix | blended the inorganic filler with polytetrafluoroethylene resin.

The mixed material 10 is extruded toward the tip of the extruder 1 and passes through the die 2 provided at the tip. The die 2 is a so-called circular die which extrudes a mixture, i.e., the mixed material 10 into an annular shape, and the mixture passes through the cross-sectional hole 2a of the die 2, thereby forming a continuous annular shape. The long product 20 is extruded.

Next, the continuous annular long object 20 molded by the extruder 1 is cut into a predetermined dimension by the cutting process shown in FIG. 2 (A). It cuts and the cut | disconnected object 22 is obtained. Then, by pressing the plate 22 on a flat plate and widening it by the rolling step shown in FIG. 2B, it is repeatedly rolled until a predetermined thickness is obtained. Thereafter, the soft sheet 30 shown in FIG. 2C is manufactured through each step of drying, firing, and modification not shown.

As an extruder used by the said extrusion process, conventionally used extruders, such as a hydraulic press type extruder and a screw type extruder, can be used. Moreover, as the rolling mill used at the said rolling process, the conventional rolling mill can be used. In addition, by cutting the long object 20 in the extruder 1 immediately after the passage of the cross-sectional hole 2a, you may perform a cutting process and an extrusion process integrally.

In the extrusion process, by extruding the long product 20 in an annular shape, extrusion molding at a high extrusion ratio becomes possible, as compared with the case of extruding the long material 120 in a flat plate form as in the prior art. The fiberization of the fluororesin can be promoted. This is because in order to promote the fiberization of the fluororesin in the extrusion step, it is necessary to increase the extrusion ratio and increase the shear force acting at the time of extrusion, and in order to extrude at a high extrusion ratio, it is indispensable to extrude in a ring shape. .

In the case of extrusion into a flat plate as in the prior art, the shearing force acting on the end portion becomes larger than the central portion. In addition, when the extrusion ratio is made high, the shear force acting at the time of extrusion is also increased. Therefore, when extrusion is performed on a flat plate at a high extrusion ratio, the difference in shear force acting at the center and the end becomes large, and the progress of fiberization at the center and the end is different.

By the way, when fiberization progresses, malleability is lost and resistance with the die contact surface at the time of extrusion increases. Therefore, when extrusion is performed on a flat plate at a high extrusion ratio, the resistance at the time of extrusion at the center portion and the end portion is different, so that extrusion cannot be performed uniformly, or a splitting problem occurs at the center portion.

On the other hand, in the case of extruding in an annular shape as in the present invention, since there is no end portion (cut line), the shearing force acts uniformly regardless of the cross-sectional position, and the progress of fibrosis is also about the same. Therefore, since there is no resistance difference at the time of extrusion, the conventional problem does not arise, and extrusion molding at a high extrusion ratio is attained.

From this fact, the long product 20 of the present invention extruded at a high extrusion ratio has undergone fibrous growth as compared with the conventional long object 120, and therefore the number of rolling in the rolling process can be reduced. In addition, there is no need to fold and overlap. Therefore, since the sheet end is not deteriorated in dry as in the prior art, the step of cutting the sheet end is unnecessary, and the yield is improved.

The extrusion ratio is defined as (in-cylinder cross-sectional area of the extruder) / (cross-sectional area of the cross-sectional hole of the die). As described above, the higher the extrusion ratio, the lower the number of rollings in the rolling process. On the other hand, if the extrusion ratio is too high, extrusion becomes difficult and the efficiency in the extrusion process is deteriorated. As extrusion ratio in this invention, 5 or more are preferable and it is preferable to set it as 5-10 especially.

In the above embodiment, the cross-sectional shape of the long product is taken as an example of an annular shape, but the cross-sectional shape of the long product of the present invention is not limited to an annular shape. For example, an elliptical shape 40 as shown in Fig. 3A, a shape 60 in which two circles as shown in Fig. 3B overlap, and 3 as shown in Fig. 3C. The shape 80 etc. which two circles overlapped may be sufficient. That is, what is necessary is just a cross-sectional shape without a cut line so that a density difference may not generate | occur | produce in any part of long object when extruded from an extruder. In addition, in this specification, "an annular shape" shall mean that it is a shape without a cut line.

As mentioned above, although the manufacturing method of the soft sheet was demonstrated to the preferable embodiment of this invention as an example, this invention is not limited to the said embodiment. Various modifications are possible without departing from the object of the present invention.

Example

Hereinafter, the Example of this invention is described compared with a comparative example. In the following description, the manufacturing method of the soft sheet of this invention shown in FIG. 1 and FIG. 2 is an Example, and the manufacturing method of the soft sheet of the prior art shown in FIG. 4 and FIG. 5 is made into a comparative example.

In addition, these Examples and a comparative example are for demonstrating this invention further more concretely, and this invention is not limited only to the range of an Example.

(Raw material)

Raw materials of the material 10 of the example and the material 110 of the comparative example are as shown in Table 1.

(Extrusion ratio)

In the present Example, the extrusion ratio of Example is 7.5 and the extrusion ratio of Comparative Example is 5.0.

(Dimension of cut before rolling)

As shown in Table 2, the dimension of the cut before roll 22 in an Example is 305 mm in width, 20 mm in thickness, and 490 mm in length. In addition, the dimension of the cut before roll 122 in a comparative example is 365 mm in width, 15 mm in thickness, and 620 mm in length. The cuts 22 and 122 are rolled until they reach 1.5 mm which is the sheet thickness of the finished product.

(Rolling frequency)

As shown in Table 2, the rolling frequency in an Example is set to half the number of times compared with 30 times which is 15 times and the rolling frequency of a comparative example. This is because, in the Examples, the fiberization of polytetrafluoroethylene resin (PTTE) is advanced in the extrusion process. Moreover, in the Example with few rolling times, since a sheet edge does not dry deteriorate, the process of cutting a sheet edge becomes unnecessary. By reducing the number of rollings and omitting the step of cutting the sheet end, in the examples, as shown in Table 2, it was confirmed that a significant reduction in the rolling time per sheet can be achieved.

(Product properties)

Table 3 shows the physical properties of the soft sheet produced by the molding method. In addition, the physical-property value shown to No.1-No.8 of the Example in Table 3 extracts 8 test pieces from one sheet of product (1100 mm x 1100 mm) by punching, respectively, Physical properties of the gasket are measured.

[Evaluation standard]

Tensile strength (length): Good at 10.8 Kgf / mm2 or more

Tensile strength (horizontal): Good at 10.8 Kgf / mm2 or more

Compression rate: good at 4-10%

Recovery rate: good at 40% or more

Specific gravity: Good at 2.20 to 2.40 g / mm2 or more

Sealing property: It is left to stand for 30 minutes in an environment of a temperature of 200 ° C, and the leakage is measured.

Appearance: determined by limit sample

From Table 3, it was confirmed that the soft sheet of the example had the same physical properties as the soft sheet of the comparative example.

(yield)

In Table 4, the yield of an Example and a comparative example is shown. In Example, since the sheet edge part was not cut at the time of a rolling process, the yield of an Example became 85% with respect to the yield of 65% of a comparative example, and it confirmed that the yield improved significantly in the Example.

From the above examples and comparative examples, according to the manufacturing method of the soft sheet of the present invention, the rolling process can be shorter than before, and the yield is also improved. It was confirmed that it became possible.

1, 100 extruders
2, 102 die
2a, 102a section hole
4, 104 Hopper
8, 108 cylinders
10, 110 Mixed Material
20, 120 longs
22, 122 cuts
30, 130 soft sheet
40 oval
60 Two Circles Overlaid
80 Three Circles Overlaid
124 seat ends

Claims (4)

As a method for producing a soft sheet,
An extrusion step of preparing a die having a mixture which is a raw material of the soft sheet and a cross section hole through which the mixture passes, and passing the mixture through a cross section hole of the die;
A cutting step of cutting the long articles formed by the extrusion step to obtain a predetermined cut piece;
It has a rolling process of rolling the predetermined | prescribed cut object obtained by the said cutting process, and shape | molding a sheet of uniform property,
As a material of the said mixture which mix | blended an inorganic filler with a fluororesin,
A cross-sectional shape of the long product formed by the extrusion process is cyclic. The method of claim 1,
The fluorine resin is a polytetrafluoroethylene resin, characterized in that the manufacturing method of the soft sheet. The method according to claim 1 or 2,
And the proportion of the inorganic fillers in the material of the mixture is 20% by weight or more. 4. The method according to any one of claims 1 to 3,
Extrusion ratio in the said extrusion process is 5-10, The manufacturing method of the soft sheet characterized by the above-mentioned.

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