WO2005061567A1

WO2005061567A1 - Non melt processable polytetrafluoroethylene and fine powder thereof

Info

Publication number: WO2005061567A1
Application number: PCT/JP2004/019250
Authority: WO
Inventors: Makoto Ono; Yasuhiko Sawada
Original assignee: Daikin Industries, Ltd.
Priority date: 2003-12-22
Filing date: 2004-12-22
Publication date: 2005-07-07
Also published as: CN100463929C; JPWO2005061567A1; JP4951970B2; CN1898282A

Abstract

A non melt processable polytetrafluoroethylene fine powder, characterized in that a stretched article for measurement (A) prepared by stretching an extruded material from the powder at 300˚C exhibits a tensile strength at break of 32.0 N or more and has a specific surface area of 11000 m2/kg or more; and a non melt processable polytetrafluoroethylene material from the fine powder. The non melt processable polytetrafluoroethylene fine powder provides a stretched material being excellent in the tensile strength at break.

Description

Specification

Non-melt processable polytetrafluoroethylene and its fine powder

The present invention relates to non-melting polytetrafluoroethylene and a fine powder thereof.

Background art

[0002] A fine powder of a homopolymer of tetrafluoroethylene [TFE] is obtained by using an extruded product obtained by adding an extrusion aid and extruding a paste to a sealing material or the like without firing. It is known that when the extruded product is stretched, only the porosity is reduced without substantially reducing the cross-sectional area as compared with before the stretching, and a porous stretched product can be obtained!

[0003] In general, a stretched TFE homopolymer becomes porous due to stretching of primary particles of the TFE homopolymer to form a node fibril, and has a specific surface area as compared with a fine powder of the same weight. It is known to grow. This porous stretched body is used as it is as a sealing material without firing, or fired to form a tough continuous stretched sheet for various uses.

[0004] Stretching of an extruded body to obtain a porous stretched body is excellent in stretchability, whereby a stretched body in which nodes and fibrils are uniformly present can be obtained without breaking the extruded body. Is preferred. A stretched body in which nodes and fibrils are uniformly present generally has excellent tensile breaking strength. The stretchability is better as the polymer has higher crystallinity, and the homopolymer of TFE usually has higher crystallinity.

[0005] As a method of obtaining a fine powder of a homopolymer of TFE having excellent stretchability, a method of starting polymerization of TFE in an aqueous medium at 55 to 120 ° C and continuing polymerization after adding a polymerization terminator is used. Is disclosed (for example, see Patent Document 1). However, there is no description on the specific surface area and tensile breaking strength of a stretched product obtained using a fine powder of a homopolymer of TFE.

[0006] As a method of obtaining a fine powder of a homopolymer of TFE having excellent stretchability, the polymerization of TFE is started at a low temperature, the temperature is raised after the start of the polymerization, and the polymerization is terminated in the presence of a liquid stabilizer. A method for causing this to occur has been disclosed (for example, see Patent Document 2). The stretched product obtained by stretching the obtained TPE homopolymer fine powder extruded product 24 times at 300 ° C while applying a tensile force has a tensile breaking strength in Examples in which the specific surface area is not described. There was a problem that the maximum was only 3.25kgf (31.87N).

[0007] In addition to the problem that the tensile strength at break is insufficient for the fine powder of the homopolymer of TFE, when extruding paste, there is a problem that extrusion pressure is high and extrusion processability is poor. To improve extrusion processability, increasing the amount of extrusion aid added during paste extrusion can lower the extrusion pressure.However, increasing the amount of extrusion aid decreases the tensile strength at break of the stretched product! There was a problem.

[0008] As a method for improving the extrudability, another method is known in which TFE is copolymerized with a small amount of another monomer to form modified polytetrafluoroethylene [modified PTFE]. I have. The modified PTFE fine powder has better extrusion processability than the TFE homopolymer fine powder, but when the extruded product obtained by paste extrusion is stretched, the modified PTFE crystallizes from the TFE homopolymer. However, there is a problem that even if the extruded product breaks in the middle of stretching, or even if it can be stretched, the molecular orientation of the obtained stretched product is poor, and the tensile strength of the stretched product is greatly reduced. Was.

[0009] As a fine powder of modified PTFE, there is disclosed a method for obtaining a modified PTFE fine powder obtained by copolymerizing hexafluoropropylene [HFP], perfluoro (propylbutyl ether) [PPVE], etc. with TFE. (For example, see Patent Document 3). The amount of monomers such as HFP and PPV E is less than 0.5% by weight of the resulting modified PTFE fine powder. The ratio of the stretched body obtained by molding and stretching this modified PTFE fine powder. The surface area and tensile strength at break are described.

[0010] As the fine powder of the modified PTFE, the other, TFE and 0.1 005-0. 05 mole ^_0/0 of CH

2

= CH—Rf (wherein Rf represents a perfluoroalkyl group having 11 to 10 carbon atoms), and a modified PTFE fine powder obtained by copolymerizing with a fluoromonomer represented by the formula: (See, for example, Patent Document 4). This method of polymerizing the modified PTFE is an ordinary method in which unreacted monomers are released and the reaction system is terminated under normal pressure.

[0011] The fine powder of polytetrafluoroethylene described in Patent Document 4 has excellent extrusion processability and elongation. The purpose is to improve the appearance and uniformity of the stretched body, and there is a problem that the strength of the stretched body obtained by molding and stretching by 10 times at 250 ° C is only 6.76 N. The specific surface area and tensile strength at break are described. /.

[0012] As a fine powder of polytetrafluoroethylene having excellent stretchability, the standard specific gravity is 2.

It is known that the fine powder of polytetrafluoroethylene having a tensile rupture strength of not more than 160 and having a tensile breaking strength of 32.0 to 49.ON may be modified PTFE (for example, see Patent Document 5). . However, the specific surface area of this modified PTFE when processed into a stretched body is not known.

Patent Document 1: Japanese Patent Publication No. 58-39443

Patent Document 2: Japanese Patent Application Laid-Open No. 2000-143727

Patent Document 3: JP-A-2000-143707

Patent Document 4: JP-A-11-240917

Patent Document 5: Japanese Patent Application Laid-Open No. 2002-201217

Disclosure of the invention

Problems to be solved by the invention

[0013] An object of the present invention is to provide a non-melt-processable polytetrafluoroethylene fine powder and a non-melt-processable polytetrafluoroethylene which provide a stretched body having excellent tensile breaking strength in view of the above-mentioned current situation. . Means for solving the problem

According to the present invention, a 300 ° C. stretched body for measurement A obtained by stretching an extruded body at 300 ° C. has a tensile breaking strength of 32.ON or more and a specific surface area of 11000 m ² Zkg or more. It is a non-melting polytetrafluoroethylene fine powder characterized by the following characteristics.

The present invention provides a non-melt-processable polytetrafluoroethylene film having a tensile breaking strength of 34.ON or more, which is obtained by stretching an extruded product at 320 ° C. It is a polyethylene fine powder.

[0015] The present invention is obtained by stretching an extruded product at 300 ° C with a tensile strength at break at 320 ° C for measurement obtained by stretching an extruded product at 320 ° C. It is characterized by being at least 115% of the tensile breaking strength of 300 ° C stretched body A for measurement. Non-melt processable polytetrafluoroethylene fine powder.

[0016] The present invention is characterized in that a 300 ° C stretched body for measurement C obtained by stretching an extruded body at 300 ° C has an amorphous coefficient of 0.08 to 0.19. Non-melt processable polytetrafluoroethylene fine powder.

The present invention provides a non-melting process characterized in that a 320 ° C. stretched body for measurement C obtained by stretching an extruded body at 320 ° C. has an amorphous coefficient of 0.08 to 0.19. It is a conductive polytetrafluoroethylene fine powder.

The present invention is a non-melting PTFE obtained by copolymerizing tetrafluoroethylene and perfluoromethyl vinyl ether, and has an amorphous coefficient of 0.6-0. It is a non-melt processable PTFE characterized by being 22.

The present invention is a stretched product obtained by stretching an extruded product obtained by paste extrusion from the non-melt-processable polytetrafluoroethylene fine powder.

The present invention is a stretched body made of the non-melt-processable PTFE resin.

Hereinafter, the present invention will be described in detail.

[0018] The non-melt-processable polytetrafluoroethylene fine powder of the present invention is a fine powder that also has a non-melt-processable PTFE (non-melting force PTFE) force. In this specification, the term "non-melting PTFE" refers to a very small amount of a comonomer together with tetrafluoroethylene [TFE] (hereinafter referred to as a "minor amount comonomer"). PTFE obtained by polymerizing PTFE, which does not have melting force. The "trace modification" in the trace-modified PTF EJ means that a very small amount of a comonomer is polymerized together with TFE without significantly impairing the properties of the homopolymer of TFE. In the present specification, the above-mentioned "trace amount comonomer" is a monomer copolymerizable with TFE other than TFE, which means copolymerization of TFE with a very small amount as described later.

[0019] The non-melt processable PTFE generally has the concept of being included in what is called "polytetrafluoroethylene" in that it is a polymer having TFE as a main monomer in common. It is. In the present specification, the term "polytetrafluoroethylene (PTFE)" is used to refer to TFE homopolymer and Z or TFE to such an extent that the properties of the homopolymer of TFE are not significantly impaired. It means modified PTFE obtained by polymerizing monomers other than TFE together with E. “Modification” in the above “modified PTFE” means that monomers other than TFE are polymerized together with TFE to such an extent that the properties of the homopolymer of TFE are not significantly impaired. The "modified" in the modified P TFEJ is not limited to those in which the amount of monomers other than TFE is very small relative to TFE as in the above "micro-modified", and the above-mentioned "micro-modified PTFE" Similarly, the “modified PTFE” is conceptually different from the “micro-modified PTFE” described above.

[0020] As is clear from the fact that the above-mentioned non-melting PTFE is limited to those subjected to the above-mentioned micro-modification, the "PTFE" in the term "non-melting PTFE" is apparent. Rather than referring to homopolymers of TFE and Z or modified PTFE, it is merely part of the term "non-melt processable PTFEJ t," above.

[0021] The non-melting PTFE fine powder of the present invention is obtained by stretching an extruded product obtained by paste extrusion from the non-melting PTFE fine powder of the present invention under specific conditions described below. Are characterized in that the stretched bodies for various measurements obtained by the above have the following physical properties. Hereinafter, in the present specification, the above-mentioned “extruded molded article” refers to a molded article obtained by extruding a non-melted PTFE fine powder from a paste of the present invention. Baking at a temperature equal to or higher than the melting point of The non-melt processable PTFE fine powder of the present invention has at least one property selected from the group consisting of property (1), property (2), property (3), property (5) and property (6) described below. It is a thing.

[0022] The characteristic (1) shows that the tensile strength at break of the extruded body at 300 ° C for measurement obtained by stretching the extruded body at 300 ° C is not less than 32.ON. ! /

The 300 ° C stretched body A for measurement is a stretched body for measuring the tensile breaking strength, and is obtained by stretching the extruded body under the conditions described below while heating the extruded body to 300 ° C.

The property (1) has a tensile breaking strength within the above range for the 300 ° C. stretched body A for measurement, and the specific surface area of the 300 ° C. stretched body A for measurement is 11000 m ^2. It is preferably Zkg or more. For the above measurement, 300 ° C stretched body A, bow I tension breaking strength It is sometimes referred to as "characteristic (11)" collectively that the force is ON or more and the specific surface area is 11000 m ² / kg or more.

[0024] PTFE generally has a small average primary particle diameter, and thus the obtained extruded product has a large number of contacts between primary particles. In the C stretched body A, the specific surface area tends to increase. On the other hand, when the average primary particle size is large, the number of contacts between the primary particles in the extruded product is small, and the specific surface area in the 300 ° C stretched product A for measurement tends to be small.

Since the non-melting PTFE fine powder of the present invention has a large specific surface area as shown in the above range, it is considered that the average primary particle diameter is small. When the fine powder is made of a homopolymer of TFE, the average primary particle diameter of the non-melting PTFE fine powder of the present invention is as small as the average primary particle diameter!

The non-melt-processable PTFE fine powder of the present invention preferably has an average primary particle diameter of 0.1 to 0.5 m. A preferred lower limit is 0.3, and a preferred upper limit is 0.3 μm.

In the present specification, the above-mentioned “primary particles” are particles having a PTFE force before aggregation, which will be described later, and have no history of heat treatment at a temperature equal to or higher than the melting point of PTFE after the polymerization reaction.

The “average primary particle size” means the number average particle size of the “primary particles”.

The above-mentioned `` average primary particle size '' is a calibration curve between the transmittance of 550 nm projected light per unit length and the average particle size determined from an electron micrograph of a PTFE aqueous dispersion having a fixed solid content. The transmittance is measured for an aqueous dispersion of a fluoropolymer prepared and measured, and the value is obtained indirectly based on the calibration curve.

[0025] The non-melting force PTFE fine powder of the present invention has a tensile strength at break of 32.ON or more for a 300 ° C stretched body A for measurement. It can exhibit excellent durability as compared with the expanded PTFE. In general, the PTFE-extended body changes its structure into a knot portion also called a node and a fiber portion also called fibril when the PTFE-next particles are stretched, so that the specific surface area is larger than that before stretching. It has increased. The stretched PTFE body is in the state before the heat setting described below is performed In this case, as the specific surface area is larger, a larger number of nodes and fibrils are present evenly per weight, and the tensile strength at break increases. The non-melt-processable PTFE fine powder of the present invention has a specific surface area of 11000 m ² Zkg or more for the 300 ° C stretched body A for measurement, and thereby has a tensile strength at break of the 300 ° C stretched body A for measurement. 32. It is possible to set it to ON or higher.

[0026] The non-melting PTFE fine powder of the present invention is a finely modified PTFE fine powder, and since the surface of the non-melting processable PTFE colloidal particles has a high molecular weight as described later, it is used for measurement at 300 ° C. It is considered that the specific surface area of the stretched body A is larger than the specific surface area of the stretched body obtained from the fine powder of the homopolymer of TFE. It is considered that the tensile rupture strength of is increased.

[0027] A preferred lower limit of the tensile strength at break of the 300 ° C stretched body A for measurement is 32.5N, and a more preferred lower limit is 33.ON. The tensile breaking strength of the 300 ° C stretched body A for measurement may be 40.ON or less in terms of durability as long as it is within the above range.

The lower limit of the specific surface area of the 300 ° C. stretched body A for measurement is preferably 11500 mg. If the specific surface area of the 300 ° C stretched body A for measurement is within the above range, the tensile breaking strength of the 300 ° C stretched body A for measurement is within the above range even if it is 17 000 m ² Zkg or less. Having.

The 300 ° C stretched body A for measurement described above may have a tensile strength at break of 32.ON or more and a specific surface area of 11500 m ² Zkg or more! / ヽ.

[0028] The property (2) indicates that the tensile strength at break of the stretched body at 320 ° C for measurement obtained by stretching the extruded body at 320 ° C is 34.ON or more. ! /

The above-mentioned 320 ° C stretched body A for measurement is a stretched body for measuring the tensile breaking strength, and is obtained by stretching the extruded body under the conditions described below while heating the extruded body to 320 ° C.

[0029] The above property (2) shows that the 320 ° C stretched body A for measurement has a tensile breaking strength within the above range, and the specific surface area of the 320 ° C stretched body A for measurement is 9000 m ² It is preferably Zkg or more. For the above stretched body at 320 ° C for measurement, the tensile strength at break was not less than ON and the specific surface area was not less than 9000 m ² / kg. 1) ".

[0030] The non-melting force PTFE fine powder of the present invention has a tensile breaking strength of 34.ON or more for a stretched body 320 ° C for measurement of 34.ON or more. It can exhibit excellent durability as compared with the expanded PTFE. The specific surface area of the 20 ° C stretched body A for measurement above is similar to the specific surface area of the stretched body obtained from the fine powder of the homopolymer of TFE, and the stretched body for measurement at 300 ° C. It is smaller than the specific surface area for A. In general, as the specific surface area of a stretched body increases, its tensile breaking strength also increases.However, in the non-melt-processable PTFE fine powder of the present invention, the tensile breaking strength of a 320 ° C stretched body A for measurement is measured. Although the specific surface area of the 320 ° C stretched body A is smaller than that of the 300 ° C stretched body A for measurement, the tensile strength of the 300 ° C stretched body A for measurement is It is significantly higher than the breaking strength.

[0031] In the non-melting force PTFE fine powder of the present invention, the tensile strength at break of the stretched body A at 320 ° C for measurement is significantly larger than the tensile strength at break of the stretched body A at 300 ° C for measurement. However, this change in tensile rupture strength is considered to be due to the fact that the extrudate is heat-fixed to a part of the extrudate when it is stretched at 320 ° C. The heat setting is sometimes referred to as heat setting.

[0032] The above-mentioned "heat setting" means that a local strain generated inside the stretched body by stretching is stabilized by heating the extruded body in a state where tension is applied. When the above heating temperature is about 300 ° C, the above heat setting does not occur. The stretched body can significantly reduce post-shrinkage, sagging, generation of wrinkles, and the like by performing the heat setting. In general, a stretched PTFE body is one in which tensile breaking strength is increased by performing heat setting after stretching. Heat setting of a stretched product obtained using conventional PTFE fine powder is performed by heating the material to a temperature higher than the melting point of PTFE. May be broken.

[0033] The heat setting of the stretched body obtained using the non-melting PTFE fine powder of the present invention is a slight modification of the non-melting PTFE fine powder of the present invention. It is thought that it can be performed stably at 20 ° C and at a temperature lower than the melting point of PTFE without breaking the molecular chains of non-melting PTFE. [0034] The non-melting force PTFE fine powder of the present invention is heat-fixed because the specific surface area of the stretched body A at 320 ° C for measurement is 9000 m ² Zkg or more. The tensile rupture strength of the 320 ° C stretched body A can be set to 34.ON or more.

[0035] A preferred lower limit of the tensile strength at break of the 320 ° C stretched body A for measurement is 35.ON, and a more preferred lower limit is 40.ON. The tensile breaking strength of the 320 ° C stretched body A for measurement may be 49.ON or less in terms of durability as long as it is within the above range.

The preferred lower limit of the specific surface area of the 320 ° C stretched body A for measurement is 9400 m ² Zkg. The specific surface area of the measurement for 320 ° C elongated body A is set in the above-mentioned range, 0.99 00m even ² ZKG less, tensile strength at break for measuring 320 ° C elongated body A is within the above above range Has a value.

The 320 ° C stretched body A for measurement described above may have a tensile strength at break of 35.ON or more and a specific surface area of 9000 m ² Zkg or more! / ヽ.

[0036] The characteristic (3) is obtained by stretching the extruded body at 320 ° C, and measuring the tensile strength at break of the 320 ° C stretched body A for measurement obtained by stretching the extruded body at 300 ° C. This means that the tensile strength at break of the obtained 300 ° C stretched body for measurement A is 115% or more.

The 300 ° C stretched body A for measurement is the same as the 300 ° C stretched body for measurement A in the above property (1), and the 320 ° C stretched body A for measurement is the same as the 320 ° C stretched body for measurement in the above property (2). ° C Same as stretched body A.

[0037] The non-melting force PTFE fine powder of the present invention has a bow I tension strength of 320 ° C stretched body A for measurement, and a bow I tension strength of 300 ° C stretched body A for measurement. Since it is 115% or more of the breaking strength, it is possible to increase the tensile breaking strength of the obtained elongated body by adjusting the temperature at which the extruded body is stretched. Fine powder of PTFE usually reduces the amount of extrusion aid (lubricant) added during paste extrusion in order to increase the tensile breaking strength of the stretched body. If the amount used is reduced, the extrusion pressure will increase and the extrusion processability will be poor. Since the non-melting PTFE fine powder of the present invention is slightly modified, Even at a temperature lower than the PTFE melting point of 20 ° C, heat setting occurs in at least a part of the stretched body, and only the stretching temperature is adjusted without reducing the amount of extrusion aid used during paste extrusion. By doing so, it is considered that the tensile rupture strength of the stretched body can be increased. The characteristic that the tensile strength at break of the obtained stretched body can be improved by setting the stretching temperature to a high value is apparent from the graph showing the relationship between the stretching temperature and the tensile strength at break as shown in FIG. The above-mentioned cases of 300 ° C and 320 ° C are merely examples, and are found in a temperature range of about 280 ° C or more and about 330 ° C or less.

On the other hand, in the case of the homopolymer of TFE, as is clear from the graph in FIG. There is little or no improvement in the tensile breaking strength of the stretched body.

Thus, the non-melting PTFE fine powder of the present invention has a single TFE even in the same stretching temperature in the temperature range where the stretching temperature is around 280 ° C or more and around 330 ° C or less. Since a stretched body having a higher tensile breaking strength than a polymer can be produced, energy efficiency is good.

[0038] The non-melting force PTFE fine powder of the present invention is prepared by using the above-mentioned stretched body at 320 ° C for measurement V, the bow I, the tensile strength at break [p (N)], and the 300 ° For the C stretched body A, the ratio [(pZq) X 100 (%)] to the bow I tension breaking strength [q (N)] is preferably 117% at the lower limit, more preferably 120% at the lower limit. Further, a more preferred lower limit is 130%. The above ratio is usually 140% or less.

When the non-melt-processable PTFE fine powder of the present invention has the above property (3), the tensile breaking strength of the stretched body A for measurement at 300 ° C. may be less than 32. Two

9. It may be less than 4N.

[0040] The non-melting PTFE fine powder of the present invention comprises:

The above properties (1): tensile strength at break of 300 ° C stretched body A for measurement is 32.ON or more, and Z or

The above property (2): the tensile strength at break of the stretched body A at 320 ° C for measurement is 34.ON or more; and The above property (3): the tensile strength at break of 320 ° C stretched body A for measurement is at least 115% of the tensile strength at break of 300 ° C stretched body A for measurement.

The above characteristic (1), which is preferable to have

The above properties (1 1) The tensile strength at break of 300 ° C stretched body A for measurement is 32.ON or more, and the specific surface area of 300 ° C stretched body A for measurement is 11000m. ² Zkg or more

Likes

The above characteristic (2)

The above properties (2-1) For the 320 ° C stretched body A for measurement, the tensile strength at break is 34.ON or more, and when the specific surface area of the 320 ° C stretched body A for measurement is 9000m ² Zkg or more, There is

Is preferred.

The non-melting PTFE fine powder of the present invention more preferably has the above properties (11), (2-1) and (3) together.

In this specification, the characteristic (11), the characteristic (2-2), and the characteristic (3) may be collectively referred to as “characteristic (3-1)”.

[0042] It is particularly preferable that the non-melt-processable PTFE fine powder of the present invention has both the above property (3-1) and the following property (4).

The property (4) is that the stress relaxation time of the stretched body for measurement 300 ° C obtained by stretching the extruded body at 300 ° C is 400 seconds or more.

The above-mentioned stretched body at 300 ° C for measurement is a stretched body for measuring the stress relaxation time, and is obtained by stretching the extruded body while heating it at 300 ° C under the conditions described below.

Although a conventional stretched PTFE body may break when fired at a temperature equal to or higher than the melting point of PTFE, the non-melting PTFE fine powder of the present invention has a 300 ° C. By setting the stress relaxation time of the stretched body B to 400 seconds or longer, it is possible to prevent the stretched body from breaking even when firing at a temperature equal to or higher than the melting point of the non-melt-processable PTFE. Therefore, when the non-melting PTFE fine powder of the present invention is used, the yield of the obtained product can be improved. A more preferred lower limit for the stress relaxation time of the 300 ° C stretched body B for measurement is 410 seconds. If the stress relaxation time of the 300 ° C. stretched body B for measurement is within the above range, 650 seconds or less, and even 550 seconds or less, the breakage of the stretched body during firing can be suppressed.

[0044] The characteristic (5) is that the amorphous coefficient of the stretched C at 300 ° C for measurement obtained by stretching the extruded body at 300 ° C is 0.08 or more and 0.19 or less. That is.

The 300 ° C stretched body C for measurement is a stretched body for measuring an amorphous coefficient, and is obtained by stretching an extruded body while heating it at 300 ° C under the conditions described below.

[0045] The amorphous coefficient [Amorphous Index; AI] indicates the degree of amorphousness. In the present specification, the "amorphous coefficient" is obtained by measuring an infrared absorption spectrum of a stretched body, the absorbance at the wave number 778Cm- ¹ is a value obtained by dividing the absorbance at the wave number 2367cm- ^1.

[0046] Wave number 778cm- ¹ is an absorption band related to the crystallinity of PTFE, and wave number 2367cm- ¹ is -CF.

2 It is the absorption band of the overtone of one stretching vibration (R. E. Moymhan, J. Am. Chem. Soc., 81, 1045 (1959)).

The higher the above amorphous coefficient, the higher the amorphousness, but the higher the amorphousness, the better the extrusion processability of the PTFE, because the extrusion pressure during the paste extrusion is lower than that of the PTFE with a low amorphous power.

[0047] The non-melting force PTFE fine powder of the present invention does not reduce the tensile strength at break of the stretched body by setting the amorphous coefficient of the stretched body C for measurement at 300 ° C within the above range. It can improve the extrudability during paste extrusion. Conventional PTFE having high amorphousness may significantly reduce the tensile rupture strength of a stretched body in which the molecular orientation of the stretched body obtained by stretching is poor. Since the surface of the non-melt-processable PTFE colloidal particles has a high molecular weight physical strength as described later, the extrudability during paste extrusion does not reduce the tensile strength of the stretched material. Can be raised.

[0048] A preferred lower limit of the amorphous coefficient of the 300 ° C stretched body C for measurement is 0.09, a more preferred lower limit is 0.12, and a preferred upper limit is 0.18. [0049] The characteristic (6) is that the amorphous coefficient of the stretched product C for measurement of 320 ° C obtained by stretching the extruded product at 320 ° C is 0.08 or more and 0.19 or less. That is.

The 320 ° C stretched body C for measurement is a stretched body for measuring an amorphous coefficient, and is obtained by stretching an extruded body at 320 ° C under the conditions described below.

[0050] The non-melting force PTFE fine powder of the present invention has a base that does not lower the tensile strength at break of the stretched body even when the amorphous modulus of the stretched body C at 320 ° C for measurement is within the above range. Extrusion processability during extrusion can be improved. The non-melt-processable PTFE fine powder of the present invention is a finely modified powder, and since the surface of the colloidal particles of the non-melt-pullable PTFE has a high molecular weight as described below, the stretched It can increase the extrudability during paste extrusion without lowering the tensile breaking strength.

A preferable lower limit of the amorphous coefficient of the stretched body C for measurement at 320 ° C is 0.10, and a preferable upper limit is 0.18.

The non-melting PTFE fine powder of the present invention comprises:

The above properties (1): tensile strength at break of 300 ° C stretched body A for measurement is 32.ON or more;

The above property (2): the tensile strength at break of the stretched body A at 320 ° C for measurement is 34.ON or more, and Z or

The above property (3): the tensile strength at break of 320 ° C stretched body A for measurement is 115% or more of the tensile strength at break of 300 ° C stretched body A for measurement; and

The above property (5): The amorphous coefficient of 300 ° C stretched body C for measurement is 0.08 or more and 0.19 or less, and Z or

Characteristics (6): The amorphous coefficient of the stretched C at 320 ° C for measurement is 0.08 or more and 0.19 or less,

The above characteristic (1), which is preferable to have

The above properties (1 1) The tensile strength at break of 300 ° C stretched body A for measurement is 32.ON or more, and the specific surface area of 300 ° C stretched body A for measurement is 11000m. ² Zkg or more, The characteristics (2) preferred by

Is preferred.

[0052] The non-melting PTFE fine powder of the present invention has the above properties (11), (2-1), (3), (5) and (6). It is more preferable to have all of them. The characteristic (1-1), the characteristic (2-1), and the characteristic (3) are collectively referred to as characteristic (3-1) as described above.

[0053] The non-melt-processable PTFE fine powder of the present invention has all of the above property (3-1), the above property (5) and the above property (6),

The above characteristics (4) The stress relaxation time for the 300 ° C stretched body B for measurement is 400 seconds or more,

It is even more preferable that they have

[0054] The non-melting PTFE fine powder of the present invention also has all of the above property (3-1), the above property (5) and the above property (6). More preferably, it has the property (7).

Characteristic (7) is that the standard specific gravity (Standard SG) of the non-melting PTFE fine powder is 2.165 or less. The value of the above standard specific gravity is such that the lower the V, the higher the average molecular weight of PTFE, and the higher the !, the lower the average molecular weight of PTFE! / ,.

[0055] The non-melting PTFE fine powder of the present invention is advantageous for stretching because the standard specific gravity is 2.165 or less.

A preferred upper limit of the standard specific gravity is 2.164. The non-melting PTFE fine powder of the present invention may have the above standard specific gravity of 2.145 or more in terms of stretching.

The non-melting PTFE fine powder of the present invention has the above properties (3-1), (4), (5), (6) and (7). It is particularly preferable to have one.

[0057] The method for producing the non-melt-processable PTFE fine powder of the present invention is carried out in an aqueous medium. A non-melt processable PTFE is obtained by conducting a polymerization reaction of tetrafluoroethylene [TFE] with a small amount of a comonomer copolymerizable with the above TFE, usually at 55 to 120 ° C for a certain polymerization time. It has a polymerization step. The non-melt processable PTFE obtained by the above polymerization step is usually colloidal particles in an aqueous medium described below.

[0058] The trace comonomer is added in a very small amount, that is, 0.0001-0.04 mol% of the total polymerization amount of the TFE. When the above-mentioned trace amount of comonomer is within the above range, a non-melt-processable PTFE fine powder obtained by performing the coagulation and drying described below can be used as a stretched body that does not reduce the extrudability during paste extrusion. It can improve the tensile strength at break. Preferred lower limit is 0.1 is 001 mole%, and a preferred upper limit is 0.03 mole ^_0/0.

In the present specification, the “total polymerization amount” means the total amount of TFE to be polymerized in the polymerization step. The total polymerization amount is the entire amount incorporated into the polymer chain of the non-melt processable PTFE in the polymerization step, and is not necessarily the same as the addition amount.

[0059] non-melt processible PTFE obtained from the polymerization step are those that trace comonomer units is 0.0001 one 0.022 mol ^_0/0. Preferred lower limit is 0.1 is 001 mole ^_0/0, the upper limit is preferably 0.020 mol%. When the above-mentioned trace amount comonomer is not used, the obtained TFE homopolymer has a tensile strength at break of less than 32. On the other hand, if the above-mentioned trace comonomer unit is larger than the above range, the above-mentioned tensile rupture strength is rather lowered, so that when producing the non-melt-processable PTFE fine powder of the present invention, the non-melt-processed PTFE fine powder is used. The amount of added calorie of the trace comonomer during the polymerization of the reactive PTFE is important.

[0060] In the present specification, the "monomer unit" such as the above-mentioned trace comonomer unit is a part of the molecular structure of PTFE and a part derived from the corresponding monomer. Means For example, the TFE unit is a portion of the molecular structure of PTFE, which is derived from TFE, and is represented by (CF-CF)-. The above “all monomer units” may vary depending on the monomer due to the molecular structure of PTFE.

twenty two

That's all of the coming parts.

In the present specification, the term “content (mol%) of trace comonomer units in all monomer units”

"" Means that the above-mentioned "all monomer units" are derived from the monomer, that is, PTFE. Means the molar fraction (mol%) of the trace comonomer derived from the trace comonomer unit in the total amount of the monomers.

When the above-mentioned trace amount of the comonomer unit is very small, it may not be possible to directly measure the mol% of the trace amount of the comonomer unit due to the detection limit by the measuring method available at the time of filing the present application. However, since the amorphous coefficient shows a value significantly higher than that of the homopolymer of TFE, it can be seen that even a very small amount is a trace modified PTFE obtained by polymerizing a trace comonomer.

[0061] The trace comonomer is added before the start of the polymerization reaction. By adding the above-mentioned trace comonomer before the start of the above-mentioned polymerization reaction, the central part of the non-melt-processable PTFE colloidal particles becomes a trace amount where the above-mentioned trace comonomer is relatively largely polymerized. It becomes modified PTF E, and gradually approaches the composition of the TFE homopolymer from the center of the colloidal particles of the non-melting force PTFE to the surface.

The method for producing a non-melting PTFE fine powder of the present invention is the same as the method for producing a fine PTFE powder disclosed in Japanese Patent Publication No. 58-39443, but before the polymerization reaction is started. In this method, a predetermined amount of a monomer is added. Therefore, as the polymerization reaction conditions, the polymerization initiator, the radical scavenger, the aqueous medium and the like, the conditions described in JP-B-58-39443 and the conjugated product can be adopted.

[0062] The polymerization reaction is carried out by adding a radical scavenger. The radical scavenger is added when an amount exceeding 10% by mass and not more than 85% by mass of the total polymerization amount of the TFE is consumed. When the content is in the above range, the colloidal particles of the non-melting PTFE can be used as gradation particles described later. A preferred lower limit is 30% by mass of the total polymerization amount of the TFE, and a preferred upper limit is 40% by mass of the total polymerization amount of the TFE.

[0063] The radical scavenger is added at a concentration of 0.7 to 20 ppm of the aqueous medium. By adding the above radical scavenger at the above concentration, the polymerization reaction rate is delayed without completely stopping the polymerization reaction. Therefore, the above polymerization reaction can be performed even after the addition of the radical scavenger.

[0064] In the method for producing a non-melting PTFE fine powder of the present invention, the TFE The polymerization reaction of the above and the trace comonomer is carried out for a certain polymerization time. The constant polymerization time is 130% of the time from the start of the polymerization reaction to the consumption of the entire TFE under the same polymerization conditions except that the radical scavenger is not added in the polymerization step. It is more time. By performing the polymerization within the above range, the polymerization reaction can be sufficiently performed even after the addition of the radical scavenger, and the surface of the obtained non-melt processable PTFE colloidal particles can be a high molecular weight substance. . A preferred lower limit is 140%, and a more preferred lower limit is 145%. Within the above range, even if the content is 350% or less, the surface of the colloidal particles of the non-fusible PTFE can be made into a high molecular weight body.

[0065] The above "under the same polymerization conditions" means that all conditions relating to the polymerization, such as the polymerization temperature, pressure, the amount of TFE added, the type and the amount of the trace comonomer, are the same as those in the above polymerization step. Means that. The constant polymerization time is evident from the fact that the radical scavenger is added when an amount exceeding 10% by mass and not more than 85% by mass of the total polymerization amount of the TFE is consumed. It is the total time of the polymerization time before adding the radical scavenger and the polymerization time after adding the radical scavenger.

[0066] The above polymerization reaction is usually carried out at 55 to 120 ° C. The polymerization reaction is carried out in the above temperature range not only before the addition of the radical scavenger but also after the addition of the radical scavenger. A preferred lower limit of the above temperature range is 60 ° C, and a preferred upper limit is 90 ° C.

[0067] The colloidal particles of the non-melt-processable PTFE may be added with a trace amount of comonomer before the start of the polymerization reaction, added with a radical scavenger to delay the polymerization reaction, and By carrying out the polymerization time reaction, the center of the colloidal particles of the non-melt-processable PTFE usually consists of trace-modified PTFE obtained by polymerizing a relatively large amount of a trace comonomer. The force at the center of the PTFE colloidal particles gradually increases as it approaches the surface, and the non-melting PTFE colloidal particles become gradation particles in which the surface of the colloidal PTFE particles has a high molecular weight. is there. In the present specification, the “central portion of the non-melt-addable PTFE colloidal particles” is a portion occupying M mass% of the center of the total mass of one colloidal particle of non-melt-processable PTFE. The above M is an average value of the values of all the colloidal particles of the non-melting PTFE obtained by the above polymerization step. 0 mass% is meant.

In the polymerization method described in JP-A-11 240917, a fluoromonomer to be copolymerized with TFE is charged only at the initial stage! /, So that the obtained colloidal particles of the TFE-based copolymer are: The center of the colloidal particles of the TFE-based copolymer is a PTFE force with a relatively large amount of fluoromonomer polymerized, and the TFE ratio gradually increases from the center of the colloidal particles of the TFE-based copolymer toward the surface. Is rising. The method for producing the non-melting PTFE fine powder of the present invention is characterized in that a trace amount of a comonomer is added before the polymerization reaction is started, and the polymerization method described in JP-A-11-240917 is used. Although seemingly in common, it consists of adding a radical scavenger during the polymerization to slow down the polymerization reaction rate, and continuing the polymerization even after the addition of the radical scavenger. On the other hand, the polymerization method described in Japanese Patent Application Laid-Open No. 11-240917 differs from the polymerization method in that a radical scavenger is not added and a means for changing the reaction rate during the polymerization reaction is not taken. It is. Since the non-melt-processable PTFE colloidal particles are obtained by controlling the polymerization reaction rate on the surface in this way, they are described in JP-A-11-240917! It is considered that the degree of polymerization is higher than the surface of the polymer colloidal particles.

Further, the non-melt-processable PTFE fine powder of the present invention is characterized in that the above-mentioned property (3) “Tensile strength at break at 320 ° C stretched body A for measurement is as good as that at 300 ° C stretched body for measurement at 300 ° C. Of at least 115% of the tensile rupture strength of the above, and the tensile rupture strength of 300 ° C stretched body A for measurement is less than 32.ON (may be less than 29.ON). In this case, if a radical scavenger is added during the polymerization to slow down the polymerization reaction rate and the polymerization is continued even after the radical scavenger is added, (i) as described above, Non-melt processability The center of the colloidal particles of PTFE is a micro-denatured PTFE that has a relatively large amount of a small amount of comonomer polymerized. The ratio of TFE gradually increases as the temperature approaches, and the table of colloidal particles of non-melting PTFE The surface may become a high molecular weight substance and become gradation particles! Or (ii) TFE homopolymer was polymerized without adding a trace amount of comonomer at the start of polymerization. Afterwards (for example, after adding a radical scavenger), add a trace amount of comonomer. It may be manufactured more.

[0069] The core-shell type PTFE particles have a distinctly or almost clearly different composition between the core portion and the shell portion. The method for producing the non-melt-processable PTFE fine powder of the present invention is based on the method of starting the polymerization reaction by delaying the polymerization reaction rate without completely stopping the polymerization reaction even after the addition of the radical scavenger. While the method is continuous until the end of the force, the method of polymerizing the core-shell type PTFE particles is generally such that the polymerization of the core portion and the polymerization of the shell portion are performed stepwise. Are different. Due to the difference in the polymerization method described above, the colloidal particles of non-melt-processable PTFE do not have a clear structural boundary, whereas the core-shell PTFE particles have a particle structure similar to that of the core. In this case, there is a difference in the particle structure that the particles are clearly or almost clearly separated from the metal part. The non-melted PTFE colloidal particles are also composed of a micro-modified PTFE polymer in which the center is polymerized with a relatively large amount of a small amount of a comonomer. The ratio of TFE gradually increases from the center to the surface of the colloidal particles of the non-molten PTFE colloidal particles. Shell-type PTFE particles differ in that the composition distribution is clearly or almost clearly different between the core portion and the shell portion. The fine powder of the core-shell type PTFE particles has a higher tensile breaking strength of the stretched body than the non-melt-processable PTFE fine powder of the present invention!

[0070] As described above, the colloidal particles of the non-melting force-curable PTFE are described in JP-A-11 240917, and the colloidal particles of the TFE-based copolymer and the core-shell type PTFE particles are described above. Is clearly different from the above, and has the above-mentioned degree of polymerization, structure and composition distribution, and is considered to be able to give excellent tensile strength to the obtained stretched body.

[0071] The trace comonomer used in the method for producing a non-melt-processable PTFE fine powder of the present invention is CF = CFC1, and has the following general formula (I)

2

CF = CFX ¹ (I)

2

(In the formula, X ¹ represents Rf ¹ or ORf ^1. Rf ¹ represents a linear or branched perfluoroalkyl group having 110 carbon atoms, and has a hydrogen atom or a chlorine atom at a terminal. Have Yes. ), A perfluorovinyl group-containing compound represented by the following general formula (Π) CH = CX ² X ³ (II)

(Wherein, X ² represents a hydrogen atom or a fluorine atom. X ³ represents a fluorine atom, Rf ² or ORf 2. Rf ² is a linear or branched perfume having 1 to 10 carbon atoms. A hydrogen-containing vinyl compound represented by the following general formula (II), which represents a fluoroalkyl group and may have a fluorine atom or a chlorine atom at the terminal.

[0072] [Formula 1]

(Wherein, X ⁴ and X ⁵ are the same or different and each represent a fluorine atom or a chlorine atom. Y represents one CF = CF— or CZ Z ² ; Z ¹ and Z ² represent Or the same or different, and is substituted by a fluorine atom, and represents an alkyl group having 116 carbon atoms.). The above-mentioned trace comonomer can be used alone or in combination of two or more of these four forces as long as it is at least one of the above-mentioned four forces.

[0074] As is clear from the above general formula (I), the above perfluorovinyl group-containing compound has a perfluorovinyl group [CF = CF-]. The above perfluobul

2

The group-containing compound is not particularly limited, and examples thereof include hexafluoropropylene, perfluoro-11-hexene, perfluoro-1-nonene, and perfluoro (alkylbutyl ether).

) And the like. The above perfluoro (alkyl vinyl ether) is not particularly limited, and examples thereof include perfluoro (methyl vinyl ether) and perfluoro (n-propyl vinyl ether). The above perfluorovinyl group-containing conjugates can be used alone or in combination of two or more.

[0075] As is clear from the above-mentioned general formula (Π), the hydrogen-containing birui conjugate has a It has a Bull group [CH = CX ² —]. As the above hydrogen-containing birui danigata

2

There is no particular limitation, and for example, Rf ² as X ³ in the above general formula (Π) is a perfluoromethyl group (perfluoromethyl) ethylene, and Rf ² is a perfluorobutyl group (perfluoro (Butyl) ethylene. The hydrogen-containing vinyl compound is

, Can be used alone or in combination of two or more.

[0076] The cyclic ether compound is a compound in which Z ¹ and Z ² in CZ ^ ² — of the above general formula (ΠΙ) are each independently bonded to a carbon atom in CZ ^ ² —. It is. The cyclic ethereal conjugate may be used alone or in combination of two or more.

[0077] As the above-mentioned trace comonomer, perfluorovinyl group-containing compounds, in particular perfluoro (alkyl vinyl ether), perfluoro (methyl vinyl ether), perfluoro (n-propyl vinyl ether) are preferred. Perfluoro (methyl vinyl ether) is more preferred, but is more preferred.

[0078] The radical scavenger used in the method for producing a non-melt-processable PTFE fine powder of the present invention is added to a free radical in the polymerization system or is chain-transferred to a free radical in the polymerization system. , Preferably does not have the restarting ability. As the radical scavenger, aromatic hydroxy conjugates, aromatic amines and Z or quinone conjugates are preferred. These compounds further have a solubility in water at 25 ° C. of 2.5 × 10— ^It is preferably at least ⁶ molZL. One or more of the above radical scavengers can be used.

[0079] The aromatic hydroxylated compound is a compound having a hydroxyl group on an aromatic ring.

The aromatic hydroxy conjugate is not particularly limited, and includes, for example, substituted or unsubstituted phenols, substituted or unsubstituted polyvalent phenols, and hydroxybenzoic acid. Phenol, m-ditrophenol, p-ditrophenol, p-ditrosophenol. Monoaminophenol, m-aminophenol, ρ-aminophenol, naphthol, catechol, resorcinol, hydroquinone, pyrogallol, phloroglucin, naphthoresorcinol, salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, gallic acid, etc. Is preferred.

[0080] The aromatic amine compound is a compound having an amino group on an aromatic ring. The aromatic amine compound is not particularly limited, and examples thereof include o-phenylenediamine and m-phenamine. And rangenamine, p-phenylenediamine, benzidine and the like. In the present specification, the aromatic compound having both a hydroxyl group and an amino group such as the above o-aminophenol is

And the above aromatic hydroxy compounds.

[0081] The above-mentioned quinone conjugates are not particularly limited, and include, for example, o-benzoquinone, p-benzoquinone, 1,4-naphthoquinone, alizarin and the like.

As the radical scavenger, hydroquinone, which is preferably an aromatic hydroxy conjugate, is more preferable.

[0082] In the method for producing a non-melt-processable PTFE fine powder of the present invention, the polymerization step is a step of performing a polymerization reaction in an aqueous medium. The aqueous medium is a medium in which the polymerization reaction can be performed, and is mainly hydraulic. The aqueous medium may include a water-soluble organic liquid such as a low-molecular-weight alcohol as long as it is mainly composed of water !, but does not include the water-soluble organic liquid! Is preferred. The polymerization reaction is carried out by adding a water-soluble polymerization initiator and a non-telogenic surfactant. The polymerization reaction can also be carried out in a reaction medium containing the aqueous medium and a non-raffin as a polymerization stabilizer.

[0083] The water-soluble polymerization initiator is not particularly limited, and examples thereof include ammonium persulfate and alkali metal persulfate. Of these, ammonium persulfate is preferable. The amount of the water-soluble polymerization initiator to be added is preferably 0.004% by mass or less of the aqueous medium. A preferred lower limit is 0.0001% by mass of the aqueous medium.

[0084] The above non-telogenic surfactant is one that can be removed to stably present colloidal particles of non-melt-processable PTFE in an aqueous medium. The non-telogenic surfactant is not particularly limited, and examples thereof include a fluorine-containing non-telogenic surfactant which is an acid having a fluorine atom bonded to a carbon atom or a salt thereof. As a fluorine-containing non-telogenic surfactant which is an acid, for example, X ⁶ (CF) COOH (where X ⁶ is hydrogen

2 n

Represents an atom, chlorine atom or fluorine atom, and n represents an integer of 6-12. ), C1 (CF CFC1)

2

CF COOH (wherein m represents an integer of 26), C F SO H (where p is 59 m 2 p 2p + l 3

Represents an integer. ) And the like. The caloric content of the non-telogenic surfactant is preferably 0.01 to 0.5% by mass of the aqueous medium. [0085] In the method for producing a non-melt-processable PTFE fine powder of the present invention, the colloidal particles of the non-melt-processable PTFE obtained by the above-mentioned polymerization step have an average primary particle diameter before agglomeration described below. Is 0.1-0.5 m. A preferred lower limit is 0.2 μm, and a preferred upper limit is 0.3 m.

[0086] The method for producing the non-melt-processable PTFE fine powder of the present invention has the above-mentioned polymerization step, and usually further comprises aggregating the colloidal particles of the non-melt-processable PTFE obtained in the above-mentioned polymerization step, It has a drying step.

[0087] The non-melting PTFE fine powder of the present invention generally preferably has an amorphous coefficient of 0.06-0.22.

A more preferred lower limit of the amorphous coefficient is 0.09, and a more preferred upper limit is 0.21. The above-mentioned amorphous coefficient is a value measured for a non-melt-processable PTFE fine powder itself before paste extrusion or stretching.

Since the non-melting PTFE fine powder has a non-melting coefficient within the above-mentioned range, the amorphous coefficient measured for the non-melting PTFE fine powder itself indicates that it is a trace-modified PTFE. Power.

The non-melt-processable PTFE fine powder has a relatively large amorphous coefficient, as in the above-described range, similar to the amorphous coefficient measured for the above-mentioned stretched body. A stretched body having improved extrudability during paste extrusion can be produced, and a stretched body having excellent tensile strength at break can be efficiently produced.

[0088] The non-melting force PTFE fine powder of the present invention can be stretched because the 300 ° C stretched bodies A and Z for measurement or the 320 ° C stretched body A for measurement have the above tensile breaking strength. When used as a body, it can exhibit excellent durability, and can be suitably used, for example, as a material for manufacturing tents, sealing materials, etc. and as a material for various coating applications. Further, examples include clothing materials; fibrous materials such as filter cloth for filter press and felt base cloth for bag filters; and membrane materials such as chemical liquid filter membranes.

The stretched body characterized in that the non-melting force-forming polytetrafluoroethylene fine powder force of the present invention can also be obtained by stretching an extruded product obtained by paste extrusion. is there. [0089] The above-mentioned non-melt-processable PTFE of the present invention is preferably obtained by copolymerizing tetrafluoroethylene [TFE] and perfluoromethyl vinyl ether [PMVE].

The non-melting PTFE obtained by copolymerizing the above TFE and PMVE is also one of the present invention. In the present specification, the “non-melt-processable PTFE obtained by copolymerizing TFE and PMVE” may be hereinafter referred to as “non-melting PTFE (A)”. In this specification, the term "non-melt-processable PTFE" without the "(A)" includes the non-melt-processable PTFE (A) but includes the non-melt-processable PTFE (A). The non-melt processable PTFE of the present invention described above is not limited to A).

[0090] The non-melting PTFE (A) uses PMVE as a trace comonomer, but the trace comonomer unit exceeds 0 mol%, and is 0.022 mol%. The following is preferred. More preferred upper limit is 0.020 mole ^_0/0, and more preferable lower limit is 0.001 mol%.

[0091] The non-melt-processable PTFE (A) of the present invention is not particularly limited, and includes, for example, those constituting the above-mentioned non-melt-processable PTFE fine powder, aqueous dispersions, solutions, pellets, and the like. It may constitute a coating or the like obtained by applying various molded articles, aqueous dispersions or solutions.

Examples of the copolymerization method include the same method as the polymerization method described in the above description of the method for producing the non-melt-processable PTFE fine powder of the present invention.

[0092] The non-melting PTFE (A) of the present invention has an amorphous coefficient of 0.06-0.22.

The amorphous coefficient is different from the amorphous coefficient measured for the above-mentioned stretched body, and fine powder is prepared in the same manner as the above-mentioned non-melting force PTFE fine powder of the present invention, and is subjected to paste extrusion molding and stretching. This is a value measured for the fine powder itself before performing the above.

[0093] The amorphous coefficient is generally related to the degree of modification, and the value of the amorphous coefficient indicates whether the object to be measured is a homopolymer of TFE or a trace modified PTFE. . In particular, if the amorphous coefficient measured for the fine powder itself, which is not a stretched body, is within the above range, which is highly relevant to the degree of denaturation, the measurement target is TFE alone. It turns out that it is not a polymer but a trace modified PTFE.

Since the non-melt-processable PTFE (A) of the present invention has an amorphous coefficient within the above range, the extrusion pressure during extrusion of the paste is low, and the extrudability is excellent.

[0094] The non-melt processable PTFE (A) of the present invention has a very small content of a very small amount of comonomer unit, and therefore has excellent tensile strength at break and is useful as a material for a stretched body having a large specific surface area. is there. For example, when the non-melting PTFE (A) of the present invention is used to produce a stretched body A for measurement at 300 ° C, it is possible to produce one having a tensile breaking strength of 32.ON or more. . A more preferred lower limit of the tensile breaking strength is 32.5N, and a still more preferred lower limit is 33.ON. The tensile breaking strength of the 300 ° C stretched body A for measurement may be 40.ON or less in terms of durability as long as it is within the above range.

[0095] When the non-melt-processable PTFE (A) of the present invention is used to prepare a 300 ° C stretched body A for measurement, one having a specific surface area of 11000 m ² / kg or more can be produced.

The specific surface area is preferably 11500 m ² Zkg or more, but may be 17 000 m ² Zkg or less as long as it is within the above range.

[0096] When the non-melt processable PTFE (A) of the present invention is used to prepare a stretched body A for measurement at 300 ° C, the tensile strength at break is 32.ON or more and the specific surface area is 11000 m ^2. It is possible to produce a material with a weight of Zkg or more.

[0097] The non-melt-processable PTFE (A) of the present invention can suitably constitute the non-melt-processable PTFE fine powder of the present invention having the above-mentioned characteristics.

Since the non-melting PTFE fine powder of the present invention (A) can suitably constitute the non-melting PTFE fine powder of the present invention, when used as a stretched body, It exhibits the tensile breaking strength as described above and can exhibit excellent durability. The non-melting PTFE powder (A) of the present invention can be suitably used, for example, in the above-mentioned applications relating to the non-melting PTFE fine powder of the present invention.

The non-melt-processable PTFE (A) stretched body of the present invention is also one of the present invention.

[0098] Production methods and measurement methods for various measurement samples and elements used for specifying the non-melting PTFE fine powder of the present invention will be described below. The data in the examples were obtained by the following production methods and measurement methods. (Paste extrusion method)

It essentially follows the method disclosed in [0046] of JP-A-2000-143727. A sample (100 g) of finely divided resin (non-melt-processable PTFE fine powder) was prepared based on the combined weight of the resin and the lubricant, and 18.0% by mass of a lubricant (trade name: IP1620 (registered trademark), (Idemitsu Petrochemical Co., Ltd.) in a glass bottle at room temperature for 3 minutes, and then leave the sample bottle at room temperature (25 ° C) for at least 1 hour before extrusion. 2. 4mm, land length 5mm, introduction angle 30 °), paste extruded into a uniform beading at room temperature at a reduction ratio of 100: 1, extrusion speed, that is, The ram speed is 20 inches Z minutes (51 cmZ minutes). The lubricant is removed from the bead by heating at 230 ° C for 30 minutes. "

[0099] (Extrusion pressure)

The extrusion pressure is a value obtained by measuring the load when the extrusion load is in an equilibrium state in the above-described paste extrusion method, and dividing the load by the area of the cylinder used for the paste extrusion.

(Content of trace comonomer)

Non-melting force PTFE fine powder was melted at a high temperature, and F ¹⁹ -NMR measurement was performed to calculate the signal force derived from the functional groups in the obtained trace comonomer.

For example, the content of PMVE used in the examples of the present application was calculated based on the following formula by performing F ¹⁹ -NMR measurement at 360 ° C.

Trace comonomer content _{(mo l%) = (4B} / 3) / (A + (B / 3)) X 100

(A =-Sum of CF signal and CF signal appearing around 118ppm, B =-52ppm

2

(Integrated value of CF signal derived from PMVE appearing in the vicinity)

Three

[0100] (Preparation method of 300 ° C stretched body A for measurement)

"Cut the bead (extruded body) to the appropriate length and fix each end so that the gap between the clamps is either 1.5 inches (38 mm) or 2.0 inches (51 mm). Heat in a circulating air oven to 300 ° C. Then release the clamp at the desired speed (stretch speed) until the separation corresponding to the desired stretch (total stretch), perform the stretch test. Except that the extrusion speed (51 cmZ instead of 84 cmZ) is different, essentially following the method disclosed in US Patent No. 4,576,869. The increase in length, usually expressed in relation to the original length. "

In the above manufacturing method, the stretching speed is ιοο% Ζ seconds, and the total stretch is 2400%.

[0101] (Method of manufacturing stretched body A at 320 ° C for measurement)

Except for heating to 320 ° C, stretch under the same conditions as for the method of preparing stretched body A for measurement at 300 ° C.

[0102] (Method of preparing a 300 ° C stretched body B for measurement)

Stretching is performed in the same manner as for the above-mentioned 300 ° C stretched body A for measurement, except that the clamp interval is 1.5 inches (38 mm) and the stretching speed is 1000% Z seconds.

[0103] (Method of preparing a 300 ° C stretched body C for measurement)

Stretching is performed under the same conditions as in the method for preparing the above-mentioned stretched body A for measurement at 300 ° C.

[0104] (Method of manufacturing stretched body C for measurement at 320 ° C)

Stretching is performed under the same conditions as in the method of preparing the above-mentioned stretched body A for measurement at 320 ° C.

[0105] (Tensile breaking strength of stretched body)

Using a bow I tension tester (trade name: AGS-500D, manufactured by Shimadzu Corporation) for the 300 ° C stretched body A for measurement and the 320 ° C stretched body A for measurement, Measure at speed.

[0106] (Specific surface area of stretched body)

The BET type one-point specific surface area measurement device (trade name: MONOSORB) was used for the 320 ° C stretched body for measurement A obtained in accordance with the method of manufacturing the stretched body for measurement 300 ° C A and the stretched body for measurement 320 ° C A. , Manufactured by Uasa Aiotas Co., Ltd.). Use 70% helium and 30% nitrogen carrier gas.

[0107] (Stress relaxation time)

The measurement of the stress relaxation time was carried out using the 300 ° C stretched body for measurement B obtained according to the above-described method for producing the stretched body for 300 ° C B as a sample, and [004 7] of JP-A-2000-143727. According to the method disclosed in

"At both ends of this bead sample (300 ° C stretched body B for measurement), an 8-inch (15 cm) long bead stretched by being connected to a fixture. The stress relaxation time is The specimen breaks after standing in an oven at a temperature above 390 ° C., ie, above 380 ° C., the melting temperature of the extended chain configuration disclosed in US Pat. No. 5,470,655. It is the time required. Since the specimen in the fixture is inserted into the oven through a slot (covered) on the side of the oven, the temperature does not drop during placement of the specimen, and therefore, US Pat. No. 4,576,869. Recovery requires a short period of time as disclosed in the issue. "

[0108] (Amorphous coefficient)

Red each of PTFE fine powder, 300 ° C stretched body C for measurement and 320 ° C stretched body C for measurement using an infrared spectrometer (trade name: FT—IR spectrometer 1760X, manufactured by PER KIN ELMER). the outer spectrum was measured, a value obtained your Keru absorbance respective wavenumber 778Cm- ¹ was divided by the absorbance at the wave number 2367Cm- ¹ and amorphous coefficient

[0109] (Standard specific gravity)

Prepare a sample according to ASTM D 4895-89 and measure the specific gravity of the obtained sample by water displacement method.

[0110] (Number average particle diameter of colloidal particles of PTFE)

The latex of PTFE colloidal particles is diluted with water until the solid content concentration becomes 0.15% by mass. The transmittance of 550 nm projected light per unit length of the obtained diluted latex and the transmission electron microscope The number standard length average particle diameter determined by measuring the directional diameter from the photograph is measured, and a calibration curve is created. Using this calibration curve, the number average particle diameter is determined from the measured transmittance of the 550 nm projection light of each sample.

The invention's effect

[0111] Since the non-melting PTFE fine powder and the non-melting PTFE fine powder of the present invention have the above-described configuration, a stretched body having excellent tensile breaking strength can be obtained.

BEST MODE FOR CARRYING OUT THE INVENTION

[0112] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to only these Examples.

[0113] Example 1 In a 6 liter stainless steel autoclave equipped with a stainless steel anchor stirrer and a temperature control jacket, 2960 ml of deionized water, 120 g of paraffin box and perfluorooctanoic acid ammonium as a non-telogenic surfactant. While charging 4.5 g of -Pam, the inside of the autoclave was replaced three times with nitrogen gas and twice with tetrafluoroethylene [TFE] gas while heating to 70 ° C to remove oxygen. Thereafter, 2 ml of perfluoro (methyl vinyl ether) [PMVE] (0.0015% by mass based on the total polymerization amount of TFE of 1000 g) was charged, TFE was injected, the system pressure was set to 0.74 MPa, and the mixture was stirred at a speed of 250 rpm. However, the temperature in the system was kept at 70 ° C.

[0114] Next, after an aqueous solution in which 20 mg of aqueous ammonium persulfate (15Omg) was dissolved was injected with TFE by adding TFE, the pressure inside the system was increased to 0.78 MPa by adding TFE, and the polymerization reaction was started. The pressure at which the pressure in the system decreases as the polymerization proceeds. TFE is added to the system while stirring at a speed of 250 rpm to increase the system temperature to 70. C, the pressure in the system was maintained at 0.78 ± 0.05 MPa.

[0115] At the time when 350 g of TFE was consumed (35.0% by mass based on the total amount of polymerization of TFE lOOOOg) from the start of polymerization, an aqueous solution obtained by dissolving 12.Omg of hydroquinone as a radical scavenger in 20 ml of water was subjected to TFE. Pressurized (at a concentration of 4.0 ppm with respect to the aqueous medium) _{o The} polymerization was continued after that, and when the polymerization amount of TFE became 1000 g from the start of the polymerization, the supply of TFE was stopped, and the gas in the system was immediately released. The pressure was reduced to normal pressure, and the polymerization reaction was terminated to obtain a latex composed of PTFE colloidal particles. The reaction time was 10.5 hours. When the polymerization was continued without adding hydroquinone, this reaction time was equivalent to 175% of the reaction time (6 hours) from the start of the polymerization until the polymerization amount of the TFE reached 1000 g.

When the number average particle diameter of the obtained PTFE colloidal particles of the obtained PTFE colloidal particles was measured, it was 0.242 m, and the number average particle diameter of the PTFE colloidal particles was 0.242 m. The concentration of the PTFE colloidal particles was 25.0% by mass.

[0117] The latex of the PTFE having a colloidal particle strength was washed by coagulation and dried at 210 ° C for 18 hours to obtain a PTFE fine powder. The physical properties of the obtained PTFE fine powder and the physical properties of various stretched bodies for measurement from which PTFE fine powder strength was also obtained were measured. Table 1 shows the results. [0118] Example 2

The charge of PMVE and 5 ml (0. 0035 mass ^_0/0 on the total polymerization amount 1053g of TFE), a添Ka卩時life of hydroquinone, a polymerization amount of TFE is the total polymerization amount lOOOg of 379 g (TFE (36.8% by mass), except that the latex composed of PTFE colloidal particles and PTFE fine powder were obtained in the same manner as in Example 1, and the number average particle diameter of the PTFE colloidal particles, The physical properties of the powder and the physical properties of the stretched body obtained from the PTFE fine powder were measured. Table 1 shows the results. When the polymerization was continued without adding hydroquinone, this reaction time was equivalent to 175% of the reaction time (6 hours) until the polymerization amount of TFE reached 1053 g.

[0119] Example 3

The charge of PMVE and 10 ml (0. 0070 mass ^_0/0 on the total polymerization amount 1053g of TFE), a添Ka卩時life of hydroquinone, a polymerization amount of TFE is the total polymerization amount 1053g of 379 g (TFE 36.0% by mass), and a latex composed of PTFE colloidal particles and PTFE fine powder were obtained in the same manner as in Example 1 except that the reaction time was changed to 9 hours. And the physical properties of the PTFE fine powder and the physical properties of the stretched body obtained from the PTFE fine powder were measured. Table 1 shows the results. When the polymerization was continued without adding hydroquinone, this reaction time was equivalent to 150% of the reaction time (6 hours) until the TFE polymerization amount reached 1053 g.

[0120] Example 4

The charge of PMVE and 20 ml (0. 015 mass ^_0/0 on the total polymerization amount lOOOg of TFE), a添Ka卩時life of hydroquinone, a polymerization amount of TFE is the total polymerization amount 1000g of 355 g (TFE 35.5% by mass), and a latex composed of PTFE colloidal particles and PTFE fine powder were obtained in the same manner as in Example 1 except that the reaction time was changed to 11.6 hours. The number average particle diameter of the particles, the physical properties of the PTFE fine powder, and the physical properties of the obtained PTFE fine powder were measured. Table 1 shows the results. When the polymerization was continued without adding hydroquinone, this reaction time was 193% of the reaction time (6 hours) until the polymerization amount of TFE reached 1000 g.

[0121] Example 5 The charge of PMVE and 50 ml (0. 037 mass ^_0/0 on the total polymerization amount 1000g of TFE), a添Ka卩時life of hydroquinone, a polymerization amount of TFE is the total polymerization amount lOOOg of 356 g (TFE 35.6% by mass), and a latex composed of PTFE colloidal particles and a PTFE fine powder were obtained in the same manner as in Example 1 except that the reaction time was changed to 17.9 hours. The number average particle diameter of the particles, the physical properties of the PTFE fine powder, and the physical properties of the obtained PTFE fine powder were measured. Table 1 shows the results. When the polymerization was continued without adding hydroquinone, this reaction time was equivalent to 298% of the reaction time (6 hours) until the polymerization amount of TFE reached 1000 g.

[0122] Example 6

The charge of PMVE and 50 ml (0. 037 mass ^_0/0 on the total polymerization amount lOOOg of TFE), perfluoro full O b octanoic acid ammonium - charged © beam 0. 45 g in the initial stage of polymerization, the polymerization of TFE is 134 g (TFE whole polymerization amount 1000g against 13.4 mass ^_0/0) and became point in Pafuruoro octanoic acid ammonium - © beam 4. Add charged 05G, the添Ka卩時life of hydroquinone, the polymerization of TFE From the PTFE colloidal particles in the same manner as in Example 1 except that the amount was 348 g (34.8% by mass based on the total polymerization amount of TFE of 1000 g) and the reaction time was 26.8 hours. A latex and PTFE fine powder were obtained, and the number average particle diameter of the PTFE colloidal particles, the physical properties of the PTFE fine powder, and the physical properties of the elongated body obtained from the PTFE fine powder were measured. Table 1 shows the results. When the polymerization was continued without adding hydroquinone, this reaction time was equivalent to 447% of the reaction time (6 hours) until the polymerization amount of TFE reached 1000 g.

[0123] Example 7

The charge of PMVE and 50 ml (0. 037 mass ^_0/0 on the total polymerization amount 1000g of TFE), perfluoro full O b octanoic acid ammonium - charged © beam 0. 90 g in the initial stage of polymerization, the polymerization of TFE is 134 g (13. 4 mass based on the total polymerization amount 1000g of TFE ^_0/0) and became point in Pafuruoro octanoic acid ammonium - a © beam 3. 60 g was charged additionally Caro, the添Ka卩時life of hydroquinone, the TFE The same procedure as in Example 1 was repeated except that the polymerization amount reached 356 g (35.6% by mass relative to the total polymerization amount of TFE of 1000 g) and the reaction time was 20.4 hours. Latex and PTFE fine powder, and the number average of PTFE colloidal particles The particle diameter, the physical properties of the PTFE fine powder, and the physical properties of the elongated body obtained from the PTFE fine powder were measured. Table 1 shows the results. When the polymerization was continued without adding hydroquinone, this reaction time was equivalent to 340% of the reaction time (6 hours) until the amount of TFE reached 100,000 g.

[0124] Example 8

In a 6 liter stainless steel autoclave equipped with a stainless steel anchor stirrer and a temperature control jacket, 2960 ml of deionized water, 120 g of paraffin wax and perfluorooctanoic acid as a non-telogenic surfactant were used. 4.5 g of -pum was charged, and while heating to 70 ° C, the inside of the autoclave was replaced three times with nitrogen gas and twice with tetrafluoroethylene [TFE] gas to remove oxygen. TFE was injected to set the pressure in the system to 0.74 MPa, and the temperature in the system was maintained at 70 ° C while stirring at a speed of 250 rpm.

Next, after an aqueous solution in which 15.Omg of ammonium persulfate was dissolved in 20 ml of water was injected with TFE, TFE was added to bring the pressure in the system to 0.78 MPa, and the polymerization reaction was started. The pressure at which the pressure in the system decreases as the polymerization proceeds. TFE is added to the system while stirring at a speed of 250 rpm to increase the system temperature to 70. C, the pressure in the system was maintained at 0.78 ± 0.05 MPa.

As for the polymerization initiation power, when 363 g of TFE was consumed (36.3% by mass based on a total polymerization amount of TFE of 1000 g), an aqueous solution in which 12.Omg of hydroquinone was dissolved as a radical scavenger in 20 ml of water was injected with TFE ( (The concentration is 4.0 ppm with respect to the aqueous medium.) _{O The} polymerization continues after that, and when TFE power is 920 g (92.0% by mass based on the total polymerization amount of TFE of 1000 g), perfluoro (methyl vinyl ether) is consumed. [PMVE] 15 ml (0.0105% by mass with respect to the total polymerization amount of TFE of 1000 g) was charged and polymerization was continued.

When the polymerization amount of TFE reaches 1000 g from the start of polymerization, supply of TFE is stopped, the gas in the system is immediately released to normal pressure, the polymerization reaction is terminated, and the PTFE colloidal particles Got. The reaction time was 28.9 hours. When the polymerization was continued without adding hydroquinone, this reaction time was equivalent to 482% of the reaction time (6 hours) from the start of the polymerization until the polymerization amount of the TFE reached 1000 g.

[0125] Comparative Example 1

The charge of PMVE and 100 ml (074 mass ^_0/0 0.5 based on the total polymerization amount 1000g of TFE) The hydroquinone was added to Example 1 except that the polymerization time of TFE was 350 g (35% by mass based on the total polymerization amount of TFE lOOOOg) and the reaction time was 22.8 hours. In the same manner, a latex comprising PTFE colloidal particles and PTFE fine powder were obtained, and the physical properties of the PTFE fine powder and the physical properties of the stretched body obtained from the PTFE fine powder were measured. Table 1 shows the results. This reaction time was 380% of the reaction time (6 hours) until the polymerization amount of TFE reached 100,000 g when the polymerization was carried out without adding hydroquinone.

[0126] Comparative Example 2

The charge of PMVE and 200 ml (0. 0.99 mass ^_0/0 on the total polymerization amount lOOOg of TFE), a添Ka卩時life of hydroquinone, a polymerization amount of TFE is the total polymerization amount lOOOg of 380 g (TFE 38 mass%), and a latex composed of PTFE colloidal particles and PTFE fine powder were obtained in the same manner as in Example 1 except that the reaction time was changed to 26.6 hours. The physical properties of the stretched body obtained from the PTFE fine powder were measured. Table 1 shows the results. This reaction time was 443% of the reaction time (6 hours) until the polymerization amount of TFE reached 100,000 g when the polymerization was carried out without adding hydroquinone.

[0127] Comparative Example 3

Without adding PMVE, the addition time of hydroquinone was set to the time when the polymerization amount of TFE became 367 g (35.6% by mass based on the total weight of TFE of 1032 g), and the reaction time was 12. Except for 5 hours, a latex comprising PTFE colloidal particles and a PTFE fine powder were obtained in the same manner as in Example 1, and the physical properties of the PTFE fine powder and the physical properties of the stretched body obtained from the PTFE fine powder were obtained. Was measured. The results are shown in Table 1. This reaction time was equivalent to 208% of the reaction time (6 hours) required for the polymerization amount of TFE to reach 1032 g when polymerization was carried out without adding hydroquinone.

Table 1 shows the results of each example and each comparative example.

[0128] [Table 1] Example Comparative example

1 2 3 4 5 6 7 8 1 2 3 Trace comonomer

Type PMVE PMVE PMVE PMVE PMVE PMVE PMVE PMVE PMVE ― Denaturation amount: (mol%) N.D N.D N.D 0.01 1 0.017 0.010 0.013 N.D 0.069 Heavy Radical scavenger

Kind of 'Hito'! ! ! Quinone Hydroquinone Hydroquinone Hydrate Quinone Hydroquinone Hydroquinone Hydroquinone Hydroquinone Human Roquinone Hydroquinone Human Roquinone Addition period: Total polymerization amount of TFE (mass ½) 35.0 36.8 36.0 35.5 35.6 34.8 35.6 36.4 35.0 38.0 35.6 Reaction Time t ¹ (hour) 10.5 10.5 9.0 1 1.6 17.9 26.8 20.4 28.9 22.8 26.6 12.5 Reaction time without radical scavenger t ² (hour) 6 6 6 6 6 6 6 6 6 6 6

tVt ² (%) 175 175 150 193 298 447 340 482 380 443 208 Non-melt-processable PTFE colloidal particles

Number average particle size (m) 0.242 0.228 0.251 0.220 0.230 0.273 0.231 0.310 0.218 0.226 0.320 Non-melt processability PTFE fine powder properties

Amorphous coefficient 0.139 0.141 0.206 0.094 0.112 0.050 Standard specific gravity [SSG] 2.158 2.154 2.148 2.146 2.147 2.160 Extrusion pressure (MPa) 20.4 18.9 22.8 16.8 17.5 18.1 Tensile breaking strength (N)

320 ° C stretched body for measurement A 43.0 40.9 43.3 48.6 48.0 31.7 35.3 40.5 (non-uniform) 28.3 (non-uniform) 300 ° C stretched body for measurement A 32.8 32.8 35.0 35.6 39.9 24.1 28.5 Break during stretching Break during stretching 320 ° C stretched body A / 300 ° C stretched body for measurement A (¾) 131 125 124 137 120 132 124

O o

Elongation specific surface area (m ² / g)

Body for measurement 320 ° C stretched body A 9.52 1 1.34 14.86 9.43 9.65 9.80 14.10 14.20 7.68 Object for measurement 300 ^a C stretched body A 11.60 13.50 16.49 1 1.51 10.40 10.50 10.30 Property oo

Stress relaxation time (sec)

300 ° C stretched body for measurement B 467 540 419 482 459 416 418 699 418 604 551 Amorphous modulus

320 ° C stretched body for measurement C 0.146 0.198 0.220 300 ° C stretched body for measurement C 0.143 o

o o

o

o o

o S -— o σ p in Further, with respect to the PTFE fine powder obtained from Example 5 and the PTF E fine powder obtained from Comparative Example 3, a stretched body was produced at a specific stretching temperature in the range of 280 to 330 ° C. The breaking strength was measured. Fig. 1 shows the results.

[0130] As is clear from the results shown in Table 1, in Examples 1 to 5 in which a trace amount of a comonomer was used in a very small amount, the tensile breaking strength of the stretched body A at 300 ° C for measurement was 32. On the other hand, in Comparative Examples 1 and 2, where the amount of the trace comonomer was increased, a stretched body could not be obtained at a stretching temperature of 300 ° C, and the stretched body was not stretched at a stretching temperature of 320 ° C. The force that could be obtained The tensile strength at break was low. In Comparative Example 3, in which a trace amount of comonomer was used, the tensile strength at break of the stretched product A at 300 ° C for measurement was less than 32.ON. Above all, in Examples 4 and 5, the tensile rupture strength of the stretched body A at 300 ° C for measurement was significantly larger than that of Comparative Example 3.

[0131] As is clear from the results shown in Fig. 1, in Comparative Example 3 using a homopolymer of TFE, the tensile strength at break increased little by little even when the stretching temperature was increased. It was a component that the tensile strength at break increased remarkably with increasing temperature.

Industrial applicability

[0132] Since the non-melting PTFE fine powder and the non-melting PTFE fine powder of the present invention have the above-described constitution, a stretched body excellent in tensile breaking strength can be obtained.

Brief Description of Drawings

[FIG. 1] From the PTFE fine powder obtained from Example 5 and the PTFE fine powder obtained from Comparative Example 3, an elongated body was produced at a specific stretching temperature in the range of 280 to 330 ° C. It is a figure showing the breaking strength measured at the time of performing.

Claims

The scope of the claims

[1] The 300 ° C stretched product for measurement A obtained by stretching the extruded product at 300 ° C has a tensile breaking strength of 32.ON or more and a specific surface area of 11000m ² Zkg or more.

A non-melt-processable polytetrafluoroethylene fine powder, characterized in that:

[2] The 320 ° C stretched product for measurement A obtained by stretching the extruded product at 320 ° C has a tensile breaking strength of 34.ON or more.

[3] The non-melt-processable polytetrafluoroethylene fine powder according to claim ^2, wherein the 320 ° C stretched body for measurement A further has a specific surface area of 9000 m ² Zkg or more.

[4] For measurement obtained by stretching the extruded body at 320 ° C The tensile breaking strength of the 320 ° C stretched body A was measured by stretching the extruded body at 300 ° C. 30

It is at least 115% of the tensile breaking strength of the stretched body A at 0 ° C.

[5] The 300 ° C stretched body for measurement C obtained by stretching the extruded body at 300 ° C has an amorphous modulus of 0.08-0.19.

[6] The stretched C for measurement 300 ° C obtained by stretching the extruded body at 300 ° C has an amorphous coefficient of 0.08 to 0.19. Or non-melt-processable polytetrat described in 4

[7] The 320 ° C stretched body for measurement C obtained by stretching the extruded body at 320 ° C has an amorphous modulus of 0.008-0.19.

[8] The stretched C for measurement 320 ° C obtained by stretching the extruded body at 320 ° C has an amorphous coefficient of 0.08-0.19. Or non-melt-processable polytetrat described in 4

[9] A non-melting polytetrafluoroethylene obtained by copolymerizing tetrafluoroethylene and perfluoromethyl vinyl ether,

Amorphous coefficient is 0.06-0.22 Non-melt-processable polytetrafluoroethylene, characterized in that:

[10] Stretching an extruded product obtained by paste extrusion from the non-melting power polytetrafluoroethylene fine powder according to claim 1, 2, 3, 4, 5, 6, 7 or 8. Obtained by

A stretched body characterized in that:

[11] The non-melt-processable polytetrafluoroethylene power according to claim 9

A stretched body characterized in that: