JPS6381104A - Anisotropic liquid crystalline polytetrafluoroethylene and tetrafluoroethylene copolymer aqueous dispersion - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aqueous dispersion of polytetrafluoroethylene (PTFE) and tetrafluoroethylene (TFE) copolymers having at least one anisotropic liquid crystal phase, and White PT manufactured directly from the phase
Flashes to FE and TFEfia.

Godanno! [shimizu
] etc., Kobunshi Kakou [Kobunshi Kakou] etc.
kol 19B1, vol. 30 (issue 10), p. 473; Chemical Abstracts [C, A,] 96 (12), 8
6199; Published on March 12, 1974! Seguch
il et al., Journal of Polymer Science, j
Journal of PoIyIIer 5ci
ence's Polymer Physics E ditio
nl, vol. 12, pp. 2567-2576 (1974);
and U.S. Patent No. 2,599°750;
559,751; and U.S. Pat. No. 2,559,752
However, this phase is not a natural formation of a separate anisotropic phase, as described in British Patent Specification 813,332.
No. 2,772,4 (and effectively equivalent U.S. patents @2,772,4
No. 44), which involves the addition of a PTFE component to a viscose solution, spinning in sulfuric acid to regenerate the cellulose, followed by a sintering process to produce black PTFE fibers, bleaching the black fibers, It offers the potential to produce white PTFE fibers much more easily than by existing methods such as fabrication into white AM by treatment with strong acids at high temperatures.

The object of the invention is to produce anisotropic, liquid crystalline (liquid crystalline)
rystalline) bolite) lafluoroethylene (P T FE) and tetrafluoroethylene (T F
E) To provide a method for producing an aqueous copolymer. Another object is to provide such dispersions that can be directly fabricated as molded structures of PTFE or TFE copolymers. Another object is to provide a dispersion which can be directly processed by coagulation methods into shaped structures consisting of 1) PTFE or TFE copolymers. Another object is to provide a method for direct fabrication into molded structures.

Yet another object is to provide molded structures, such as ams produced by the method. These and other purposes will become apparent later in the text.

The present invention is directed to anisotropic, liquid crystalline polytetrafluoroethylene (P T F E >) and tetrafluoroethylene (
TFE) copolymer aqueous dispersions and white a-fibers (of polymers) produced directly therefrom.1 The anisotropic liquid crystalline dispersions of the present invention were produced according to the method disclosed in detail below. The anisotropic liquid crystalline dispersion of the present invention, which sometimes occurs naturally, can consist of a total dispersion prepared by the method described below, or it can consist of a partial dispersion. Aqueous dispersions of the latter type contain a highly non-anisotropic (i.e. isotropic) phase which is not considered part of this invention, and one or more different phases, each of which is considered part of this invention. Consists of a tropic phase. The novel anisotropic phase or phase group depends on the structure of the surfactant used in the polymerization medium and its concentration and purity, and
T:”T;'←Hhi, mAノklr1WL8l-1-)
It depends on the structure of the polymer copolymerized with TFE.

One or more anisotropic phases can be produced by the method of the invention, and the anisotropic phase(s) can constitute from about 5% to 100% by volume of the total volume of the dispersion.

When the amount of anisotropic phase(s) is less than 100% of the total volume of the dispersion, the anisotropic phase separates out as a lower layer within 72 hours, often within 4 to 72 hours after the end of polymerization.

The transmitted electron I image of the anisotropic liquid crystal dispersion of the present invention shows that a high proportion of rod-shaped PTFE (or TFE copolymer) assembled in bundles is present. PTF
Although the formation of dispersions containing rod-like particles of E has also been described in the prior art, the presence of rod-like particles per se is not the only indicator of the spontaneous formation of anisotropic liquid crystalline dispersions;
70-Lee (F 1ory), Proceedings of the Royal Society of London (P
roceeding of royal 5o
city of London), volume A234,
73 (1956), the formation of a natural anisotropic phase depends on the concentration of rod-shaped particles and their 7-spect ratio (
aspect ratio), ie both length and diameter ratio. The anisotropic phase is polarized by a cross polarizer (cr
When viewed through an ossed polarizer),
It can be detected by birefringence. Although all the factors controlling the formation of one or more anisotropic phases during the aqueous dispersion polymerization of tetrafluoroethylene (TFE) are not completely understood, the set of conditions described here is
% of the anisotropic liquid crystalline phase. The natural order present in the anisotropic phase is advantageously used for the direct production of PTFE and TFE copolymer molded articles, such as white PTFE and TFE copolymer fibers.

The structure of the surfactant present and essential during polymerization is the formula RA, where R is 1) Z-(-CF2-)x-(-CHiGHz-)
y, y is 0 or 1; X is 7 to 13; and Z is H, F, CI, or Br; or 2) W-
CF, CF(W)O-(-CF2CF(CF,)0-)
Z-CF2CF2-, -2 is 1 to 2; and W is CI or F; or 3) Z-(-CF2-)X(-CH2-)F
and y is 0.1 or 2; X is 8 to 13; and Z is H, F, CL or Br; and R1! -803
M, -COOM or -S Os N R2, where M is K0 or NH,10 in Li'', Na; R is -CxH2x+1; X is 1 to 5; be done.

The initial concentration of surfactant in the aqueous polymerization medium is important;
It must be at least equal to the critical micelle concentration (awe) of the surfactant. It has also been found that the concentration of surfactant must be greater than elle, as pointed out in Example 30 herein for one of the surfactants that can be used. Similar observations have been made for other surfactants that fall within the formula description above. However, since suitable and/or optimal surfactant concentrations can be readily determined by those skilled in the art without undue experimentation, these examples will not be discussed further.

The cmc depends on the structure of the surfactant and can be measured by various methods known in the art, e.g. The concentration at which an appreciable change in the slope of the curve occurs can be taken as cIIc.Typical cmc values for the surfactants of the invention are shown in Table 1.

In general, the amount of anisotropic phase increases as the concentration of surfactant increases above awe to an upper limit equal to the total solubility of a given surfactant in the polymerization medium. As noted for one of the available surfactants, the amount of anisotropic phase was found to reach a peak and then decrease with further increase in the concentration of the surfactant. In any case, the fluorinated surfactants used in the method of the invention appear to be somewhat expensive, so it is not economically advantageous to use very high concentrations of surfactants. In practice, the amount of surfactant used should be determined by taking into account the cost of the amount of surfactant used and the concomitant amount of anisotropic dispersion produced. As long as the initial W concentration is at least equal to cllc, it is possible for a person skilled in the art to select the optimal concentration to obtain the desired result. Suitable concentrations range from about cmc to about 5% w/v, where 0% w/v is defined as 100 times the weight of the surfactant divided by the volume of the solution; e.g., 1 wt. /vol% solution contains 1 g of surfactant in 100 ce of solution.

The purity of the surfactant is important to obtain a stable, anisotropic liquid component beverage. In general, the purity of the surfactant should be greater than 95% (and preferably greater than 99%).Of course, if excess impurities are present, their structure may be In addition, in some cases impurities adversely affect the polymerization.

Polymerization time is also important in producing the optimum amount of anisotropic liquid crystalline phase or phases. Best results are obtained with short polymerization times on the order of about 1 minute to about 120 minutes, with the amount of anisotropic liquid crystalline phase(s) and the degree of assemblage decreasing as the polymerization time increases. The optimal polymerization time for a given set of polymerization conditions can be determined by removing a portion of the polymerization reaction mixture at regular time intervals and measuring the amount of anisotropic liquid crystalline phase present in the high molecular weight. .

As is clear from the above description, the natural formation of the anisotropic liquid crystalline dispersion of the present invention is characterized by a series of It has a decisive dependence on conditions.

In the dispersion polymerization method of the present invention, the pressure of TFE is 20-2000
psig (138-13,800kPa) and 60-600 psig (414-4
140 kPa) is a suitable range. Generally, higher pressures are advantageous in producing higher molecular weight polymers.

The temperature used for polymerization is 40-150°C and 60-150°C.
A preferred range is 100°C.

Initiators that can be used in the dispersion polymerization process of the present invention include initiators commonly used in TFE polymerization and TFE copolymerization, such as cissuccinic acid peroxide, and persulfates, such as ammonium, potassium or sodium persulfate salts. Contains free radical initiators such as

The concentration of the initiator is 0.0001 to 0.1% w/v.
can be. The preferred range is 0.005 to 0
．． 020% by weight/volume.

It can be done with either Eq.

Oxygen is known to inhibit polymerization and should be virtually excluded before and during polymerization.

The preferred polymer of the invention is a homopolymer of TFE, namely P
It is TFE. However, the anisotropic dispersion of the present invention can consist of TFE and any copolymer copolymerizable therewith. The copolymers include, for example, hexafluoropropylene, vinylidene fluoride, perfluoropropyl vinyl ether, and perfluorobutylethylene. The copolymer comprises a large fraction of TFE repeating units, i.e. 50 mol% or more, preferably 80 mol% or more, and a small fraction, ie less than 50 mol%, preferably 20 mol% or less, of TFE repeating units.
It consists of repeating units of a comonomer that can be copolymerized with FE. Examples 31-34 illustrate embodiments of anisotropic dispersions of the present invention comprising TFE copolymers. In the case of certain comonomers that can be copolymerized with TFE, the comonomer solution of polymerized repeating units may be 1.±.
or less (e.g., about 1 mol %), in which case the concentration of TFE polymerized repeat units is 9
It will be appreciated that those skilled in the art will perform extra experimental maneuvers to obtain the anisotropic liquid crystalline aqueous dispersion of the present invention. It is easy to ascertain the maximum amount of comonomer that can be copolymerized with TFE without causing any damage. Preferred copolymers herein are TFE/vinylidene fluoride copolymers comprising up to 20 mol% vinylidene fluoride repeating units and more than 2 mol% hexafluoropropylene, perfluoropropyl vinyl ether or perfluorophthyl ethylene. It contains a TFE copolymer consisting of comonomer repeating units.

Rod-shaped particles of polymer are produced during polymerization. These aggregate into bundles to create the anisotropic liquid crystalline dispersion of the present invention. Transmission electron micrograph of the anisotropic liquid crystalline PTFE phase of the present invention (
Figure 1) shows the presence of long rods and a high degree of order. The length of the rod is longer than the reaction time (decreased, as shown in 2.3).
The degree of organization of the rod-shaped PTFE particles as shown in FIG. 4 also decreases. Figures 1 to 4 show Example 1, respectively.
At 3°4 and 5, the reaction time was 1.30, 60 and v.
It is a figure which shows the electron micrograph of the rod-shaped particle produced|generated after 180 minutes.

The electron diffraction pattern of a single rod-shaped PTFE particle shows that the polymer chains are aligned in the same direction as the rod, as illustrated in Figure 5. 1 As the reaction time increases, the length of the rod decreases. Consistent with this, the dimensions of the anisotropic liquid crystal phase region are also
The phases produced by carrying out the process of the invention with reaction times of 5, 30, 60 and 180 minutes (Examples 2 to 5) were
As shown in FIGS. 6 to 9, which are the results of observation using a polarizing microscope with a magnification of 100 times, there is a decrease.

Examples 1-17 herein represent embodiments of the invention in which multiphasic dispersions are produced. The upper layer of the dispersion also contains rod-shaped particles. However, in contrast to the anisotropic liquid crystalline lower phase, the rod-like particles in the upper layer are isotropically distributed. However, they can be aligned in a magnetic field and exhibit very strong birefringence. The relaxation time after removing the magnetic field was found to be approximately 10 minutes.
The lower phase constitutes from 100% or less to 0% or more.

In other embodiments of the invention, the preparation of single phase, anisotropic liquid crystalline dispersions is presented in Examples 18-24.

When examining the dispersion between cross polarizers, it was found that Example 1
The product of No. 8 is clearly shown to be birefringent as shown in FIG. The electron diffraction pattern of a single rod-shaped PTFE particle shows that the polymer chains are aligned in the same direction as the rods, which can also be seen by high-resolution transmission electron microscopy.

White PTFE or TFE copolymer a is prepared by dilute aqueous solution of calcium chloride or magnesium, 1-98% H2S
O,/water, 1-30% HCl/water, ethanol for dispersions prepared in the presence of a surfactant containing a terminal -SO, group, or a surfactant containing a terminal -SO, group. C+alls for dispersions prepared in the presence of
The anisotropic liquid crystal dispersion can be easily spun by adding the anisotropic liquid crystal dispersion to a coagulant such as a dilute, for example, 2% by weight aqueous solution of sN(CHz)s+Br. The resulting fibers exhibit extremely strong optical birefringence, indicating that oriented fibers have been produced, which can also be seen in XM measurements of the fibers, as illustrated in Figure #S10, for example.

As is clear from the above description, the anisotropic liquid crystalline dispersion produced herein according to the present invention is made of white PTFE.
Alternatively, the present invention provides an alternative method for producing TFE copolymer fibers, which differs from conventional methods requiring sintering methods, intermediate formation of black PTFE fibers, and decolorization. Fibers produced by such conventional methods are commercially available.

The properties of the fibers produced by the method of the present invention herein include, but are not necessarily limited to, the molecular weight of the polymer, the coagulant used, the spinning speed (into a solid) and the heat treatment imparted to the fiber. It depends on various factors. Generally, most of the desirable properties of fibers are increased by increasing the molecular weight of the polymer and by heat treating the fibers. When salt solutions are used as coagulants, the salts must be thoroughly washed away from the fibers.
Fiber properties may be degraded. Table 2 lists commercially available natural (black) and bleached (white) P T F E
The physical properties of the fibers are shown. Here physical property data typical of the white oriented fibers that can be provided by the method of the present invention are included in the same table for comparison.1 The data shown above uses surfactant (3). Obtained for am produced from an anisotropic liquid crystalline dispersion produced by the method of the invention, an embodiment giving a single phase, anisotropic liquid crystalline dispersion. The properties of all fibers produced from such liquid crystalline dispersions and of fibers produced from the anisotropic liquid crystalline phase of multiphase dispersions are virtually identical. In the table, strong (T) and modulus (M) beams/
Elongation (E) is expressed in denier and elongation (E) is expressed in %. Zero strength and modulus are calculated using denier at break. The heat treatment was at 370°C for about 60 seconds, and the film was stretched at 370°C to maintain its original length during the heat treatment. Further regarding the data in Table 2 and how to obtain the data, since denier is defined as grams of fiber per 900 meters of fiber, when aJIl is drawn, the denier decreases to 0 tenacity and modulus. increases as the denier decreases, so the a-fibers of the present invention exhibit higher strength and modulus at a denier of 7.

White PTFE and TFE copolymer fiber is PTFE or TFE
It can be prepared from an aqueous dispersion consisting of a mixture of an anisotropic liquid crystalline aqueous dispersion of rod-like particles of FE copolymer (the dispersion of the invention) and a commercially available aqueous PTFE dispersion consisting essentially of spherical particles of PTFE. Depending on the properties required, the mixture may consist of up to 95 1% by weight of a commercially available aqueous dispersion, based on the total weight of the polymer. This embodiment is illustrated in Examples 44 and 45.

Although the direct conversion of anisotropic liquid crystalline aqueous dispersions into fibers has been detailed above, there is no intention to limit the dispersions to such uses or to the methods described to effect direct conversion. . Those skilled in the art will readily recall other molded structures that can be made from the dispersion. One may also conceive of methods other than the coagulation method described above for carrying out the direct conversion.

The present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples. All temperatures are given in degrees Celsius.

Real JLfL-C as a uninide surfactant! Anisotropic PTFE via phase separation of PTFE dispersion using F+s COON H4
2 g of ammonium perfluorodecanoate, 200 m
1 part of water and 12 parts of 2S201 initiator were charged.

The vessel was evacuated with an oil vacuum pump, nitrogen was flushed into the reactor, and the solution was stirred for about 5 minutes. The degassing operation was repeated a total of three times.

During continuous degassing, while the reactor was filled with nitrogen, a small amount of TFE was released into the reactor to eliminate air from the TFE line (part of the degassing process). ), and after final vacuum, the stirring speed was increased to 11000
rp and the vessel with TFE at 50 psig (345
kPa).

The TFH feed was stopped and the reaction vessel was placed in a water bath (84°). The temperature of the contents begins to rise and the internal pressure increases. When polymerization begins (indicated by a decrease in internal pressure), the TF
The H supply was resumed and maintained at a constant pressure of 60 psig (414 kPa). A timer was started when the internal temperature reached 77°.

Polymerization continued for the specified times as shown in Table 3.

When left at room temperature for about 4 hours after polymerization, the dispersion exhibited phase separation. Observing both phases between cross polarizers shows that the upper phase (90-95% of the volume) is not birefringent even when left alone (Jil
However, when the dispersion was stirred, the stirring caused the particles to align and became birefringent. This arrangement (orientation) can also be caused by a magnetic field as described above. The lower phase (5-10% by volume) was as birefringent when the dispersion was left undisturbed as when it was stirred. The data are shown in Table 3, where the last two columns are the total dispersion (C
The concentrations of the polymers in T) and the lower phase (anisotropic phase) (CL) are shown in weight %, respectively.

Molecular weight (M w ) of PTFE for each of 5 Examples
T, Sawa, M, Takekisa
kisa) and S., Meehi in Sharnal Op Applied Polymer Science (J, ^
pplied polymer science)
, Vol. 17, p. 3252 (1973), as measured by differential scanning calorimeter (DSC).
It was 00. -Polymer with high molecular weight is TFE
can be produced by increasing the pressure and decreasing the initiator concentration.

! 6-10 PTFE drink phase products using various surfactants
Examples 1-5 were repeated using various surfactants and various concentrations of surfactants, as shown in Table 4. In each case, phase separation accompanied by the formation of an anisotropic phase occurred. The results obtained are shown in Table 4, including the concentration of the polymer in % by weight in the total dispersion.

QQQU(,1 dog mb F -(-CF 2CF 2-)n-CH2CH2S
Phase separation of PTFE dispersion using O3K as surfactant.
The method of Examples 1-5 was repeated using 2CH2SO:IK.

The composition of the surfactant mixture used in this experiment is as follows, expressed in weight percent: n=2:
2% n = 3: 36% n = 4: 32% n = 5: 19% n = 6: 11% Polymerization time was 30 minutes 0 When left at room temperature for about 12 hours after polymerization, the dispersion underwent phase separation. It showed. Lower phase (anisotropic phase)
constituted about 7% of the total volume.

Add 5% CaCl□ and 5% Mg to the anisotropic phase by syringe.
Good α-fibers were produced from the anisotropic phase when added to Cl2 aqueous solution.

12- PTF using C, F, COONa as a surfactant
Example 11 was repeated using 2 g of C* F + * COON a as a surfactant. After polymerization, the anisotropic PTFE dispersion d underwent phase separation overnight (approximately Upon standing (14 hours), the dispersion showed phase separation. The lower phase (anisotropic phase) occupied about 5% of the total volume.

Add the anisotropic phase to 5% CaCl2 and v5% by syringe.
When added to MgCl□ aqueous solution, good fibers were produced from the anisotropic phase.

East 1■[-YU'-Cs F ls P using C00K as a surfactant
Anisotropic PTFE dispersion 1′ through phase separation of TFE dispersion. Using 2 g of C, F, , C00K as surfactant,
The method of Example 11 was repeated using 1 mg of K 2 S 20 s as initiator. After polymerization the entire phase was open refractive for about 4 hours; phase separation occurred after 12 hours. The lower phase (anisotropic phase) occupied about 80% of the total volume. The upper phase was not birefringent.

Using the lower phase, it was possible to spin fibers as described in the text.

After brief soaking, the interphase became birefringent and fibers could be produced from the interphase. After leaving it at room temperature for 72 hours,
The lower phase (anisotropic phase) accounted for 20% of the total volume.

14- 2 g of H-(-CF,-)-, as surfactant. C
o.

Example 13 was repeated using NH. After polymerization, the dispersion showed phase separation when left overnight (about 14 hours) at room temperature. The lower phase (anisotropic phase) accounted for about 15% of the phase coalescence.

Dog JjL-Yu''-CzFsO(CF2CF(CFa)O)zcFtcF2
PTFE component compound using cO0Na as a surfactant. 1. Agent! c2F of l2t, 0(CF2
Examples 1-5 using CF(CF,)O)2cF2CFzCOONa and 1 g of KzS20s as initiator
The zero polymerization time when the method was repeated was 60 minutes.

The 0 dispersion, in which the entire phase was anisotropic after polymerization, showed phase separation when left overnight. The lower phase (anisotropic phase) accounts for approximately 1 of the entire volume.
It accounted for 5%.

Cold U Two Rainbow CICF2C (CI) (F) OCFICF (CFff)
OCF2CF 2 COON m is used as a surfactant for PTFE drinks. Anisotropic PTFE drinks undergo phase separation using 2 g of CICF2C (CI) (F
) OCF2CF (CFs) The method of Examples 1-5 was repeated using OCF2CF and CC00N. The polymerization time was 25 minutes. The dispersion showed phase separation when left overnight. The lower phase (anisotropic phase) occupied about 80% of the total volume.

PT using c, F, 5cOONH, as a surfactant
Preparation of anisotropic PTFE dispersion via phase separation of FE-containing beverages: 6 g (3%) of C, F, Co as surfactant.

The method of Example 1-5 was repeated using NH, and 1'H K and S 201 as initiators. The polymerization time was 60 minutes. 6 After polymerization - When left overnight (about 12 hours) The PTFE dispersion showed phase separation. The lower phase (anisotropic phase) occupied about 25% of the total volume.

The above experiment was carried out using only 3 g (1,5%) of CtF 1%
The experiment was repeated using C00NH. - Spinning fibers from zero dispersions (HCI
/by extrusion into ice water) could not be done.

Anisotropic P using C,F,,5O3K as surfactant
In a 400 ml glass reaction vessel equipped with a mechanical stirrer, 2 g of Ca F It S Oa K (1 wt/vol %), 200 ml of water and 10 x g of K 2 S 20 were added.
゜Initiator was charged. The vessel was evacuated with an oil vacuum pump, nitrogen was flushed into the reactor, and the solution was stirred for approximately 5 minutes. The sharp air manipulation was repeated a total of three times.

During continuous degassing, while the reactor was being filled with nitrogen, a small amount of TFE was released into the reactor to clear the TFE line of air. After finally creating a vacuum,
The stirring speed was increased to 1000 rpm and the vessel was pressurized to 50 psig (345 kPa) with TFE. TFE
The feed was stopped and the reaction vessel was placed in a water bath (84°). When the temperature of the contents began to rise and zero polymerization began (indicated by a decrease in internal pressure), the internal pressure increased, the TFE feed was resumed and maintained at a constant pressure of 60 psig (414 kPa).

The timer was started when the internal temperature reached 77°1.
Polymerization continued for the specified times as shown in Table 5.

The last column of the table shows the concentration of polymer in weight percent in the dispersion.

After polymerization, the entire dispersion exhibited anisotropic behavior. Analysis of the dispersion between crossed polarizers showed it to be birefringent. This is illustrated in FIG. 11 for the polymer of Example 19.

Example 18 was repeated except that the concentration of surfactant was 1 g (0.5% w/v). The resulting dispersion was isotropic, indicating an insufficient amount of surfactant.

C, F,? Preparation of an isotropic PTFE product using CH2CH2C00K as a surfactant. Examples 18-20 were repeated using c, F, cH2cH, coOK at 1 and 3 weight 11/vol% as surfactants. Table 6 summarizes the results, with the last column indicating the concentration of polymer in the dispersion in weight percent.

The entire polymerized phase drink exhibited anisotropic behavior. Analysis of the dispersion with a cross-shaped polarizer showed that it was birefringent.

Xl""-" - C, F,, CH2CHzCOONm is used as a surfactant Cs F + t CHt CH2C
Examples 18-20 were repeated using OON & at a concentration of 1% by weight/volume and 1 mg of KzS20e as the initiator. The concentration of polymer in the dispersion was 2.31%. No phase separation occurred and the dispersion was anisotropic.

Dog 1"[-1" - Made of PTFE using CIF, 7CH, CH2COONH4 as surfactants C, F, , CH2CH, C0QNI (
.

Example 25 was repeated using The concentration of polymer in the dispersion was 5.02%. No phase separation occurred after 72 hours. The dispersion was anisotropic.

Dog LLu2L Cs F I? Preparation of anisotropic PTFE material using CHt CH2C00L i as surfactant 'Cm F I as surfactant? CH2CH2COO
Example 25 was repeated using Li. The concentration of polymer in the 0 dispersion was 2.6%. The 1 dispersion was anisotropic.

Polymer in 0 dispersion of PTFE with CsFl7CHtCH2COOLi as a surfactant by repeating Example 27 using 10mg of KtS*Om as an initiator. The concentration of 0 dispersion was anisotropic.

Example 24 was repeated except that the surfactant concentration was 2%, the reaction time was 90 minutes, and the amount of K 2820 m was I H. After polymerization, the entire dispersion was anisotropic. The concentration of PTFE in the dispersion that behaved and was birefringent was about 6.6%, and the yield of polymer was about 13.19%.
The molecular weight was 1.71×10'.

This example shows the change in fi (in a two-phase dispersion) of the anisotropic phase formed when the amount of surfactant present during polymerization is changed.

Polymerization conditions: Polymerization of TFE at 60 psi and 80': 200 mf water; 10 shoulder 9 K2S,0, initiator; reaction time 40-50 minutes. The results are shown in Table 7, the third part of which The columns indicate the concentration of surfactant versus the ratio of 6Ta6 in the surfactant.

For three different lithium perfluoroalkanoates, polymerizations with initial surfactant concentrations below esc do not give an anisotropic phase, whereas polymerizations carried out above ClIC consistently give an anisotropic phase. This is noted in Table 7. cme again? It is noted that using csF+zcO0Li does not give an anisotropic phase. Furthermore, the amount of anisotropic phase tends to increase as the surfactant concentration increases above cmc, with the exception of CIFl at a concentration of 0.2 mol/1.

In the case of COOLi, less anisotropic phase is produced than in the case of a concentration of 0.14 mol/1.

Example 31 A medium capacity stainless steel polymerization reactor equipped with a heater, a stirrer, and a gas inlet tube was charged with 200 l of water and 4 g of C into one reactor purged with nitrogen to remove all traces of oxygen.
,F,,1coONI-1,(2%),1011g of K
20 m of 2S and 1.5 g of perfluoropropyl vinyl ether were charged. Heat the contents to 48° and add tetrafluoroethylene to bring the pressure to 6963°C.
It increased to KPa. Set the stirrer to 11000 rpm,
The contents were heated to 80° for 15 minutes and then allowed to cool to room temperature.

The entire emulsion containing 21.33% PTFE was anisotropic. Examination of the emulsion by electron microscopy showed the presence of approximately equal amounts of rods and spheres.

The infrared spectrum of the polymer showed the presence of 1% perfluorovinyl ether polymer repeat units in the copolymer.

Add the anisotropic emulsion to 5% calcium chloride solution or 3
Fibers were made directly by extrusion into an aqueous solution of % hydrochloric acid. The fibers were highly birefringent.

[200 gf> water in a small capacity stainless steel polymerization reactor equipped with a rainbow heater, a stirrer, and a gas inlet tube, parked with nitrogen to remove all traces of oxygen.
y csF + ycH2cH2cO0NH, (1%),
1. S, O, and 5 g of perfluoropropyl vinyl ether were charged.

The contents were heated to 55" and tetrafluoroethylene was added to increase the pressure to 6915 KPa.

Set the stirrer to 1000 rpm and stir the contents for 60 minutes.
It was heated to 0° and then allowed to cool to room temperature. The solution exhibited phase separation. The lower anisotropic phase (approximately 80% of the total t# liquid) was birefringent. The upper isotropic phase exhibited birefringence only upon shear force induction.

Examination of the copolymers of the two copolymers obtained by electron microscopy showed that the frame length was between 0.2 and 2 .mu.-. The copolymer also contained somewhat spherical particles.

200 g of water, 4 g into a small capacity stainless steel polymerization reactor equipped with a heater, a stirrer, and a gas inlet tube that was purged with nitrogen to remove all traces of oxygen. C of
s F + * COON H< (2%), 10 mg
of K2S and 0.5 g of perfluorobutylethylene were charged. The contents were heated to 60° and tetrafluoroethylene was added to increase the pressure to 6915 KPa. The stirrer was set at 100() rpa+ and the contents were heated to 80° for 30 minutes and then allowed to cool to room temperature.

The entire emulsion was anisotropic. The yield of copolymer is 25.
It was Ig. The copolymer contained 2% perfluorobutylethylene polymer repeat units.

Spinning fibers (in coagulants mentioned elsewhere in the text)
was possible for the entire emulsion. The properties of the fibers thus obtained are shown below.

a-fiber denier Moschelas strong stretch sintered car 2190
1.0 0.08 492 Sintered car 500 2
,3 0.54 43 While keeping the length constant, 3
Dog 1"L-1" at 70° - 2 g of C*F+*COON H4,200 in a 400all glass reaction vessel equipped with a mechanical stirrer
m1 (1 reaction n ψ5a j charged with n water and 2S2o in JIg)
- Powder was added and the solution was stirred for about 5 minutes. The degassing cycle was repeated three times. While the reactor is filled with nitrogen during continuous degassing, T
A small amount of T is added into the reactor to eliminate air from the FE line.
After releasing the FE, the stirring speed was increased to 10 after finally creating a vacuum.
00 rpm-, 5% vinylidene fluoride and 95
The vessel was pressurized to 345 KPa with a gas mixture consisting of % tetrafluoroethylene. The gas supply was stopped and the reaction vessel was placed in an 84° water bath. The temperature of the contents rose and the internal pressure increased.

When polymerization started (indicated by a decrease in internal pressure), the comonomer mixing resumed the gas feed and maintained a constant pressure of 414 kPa. The contents were heated to 80° for 60 minutes and then allowed to cool to room temperature. - The overnight solution exhibited phase separation. The lower anisotropic phase (45%) was birefringent. The yield of copolymer was 9.4 g. Testing of the copolymer by infrared spectroscopy showed the presence of 11.6% fluorinated vinylidene polymer repeat units. Spinning of fibers from the lower phase was easily possible by extrusion into 3% HCl.

Using the anisotropic phases of Examples 1-3, each of these phases was injected with 5% CaCl2 aqueous solution and 5% Mg by syringe.
PTFE fibers were produced by adding C1 into an aqueous solution. The obtained fibers can be suitably washed to remove salts. In each case, the produced fibers exhibited very strong optical birefringence indicating that oriented 411JI was obtained.

The fibers produced from the anisotropic phase of Example 2 exhibited the following properties: Modulus (M), 0.01 g/denier; Tenacity (T), 0,001 tp/denier; Elongation at break ( E), 19%.

The anisotropic phase from Examples 6-10 was added to 5% C by syringe.
Oriented PTFE fibers were prepared as described in Examples 35-37, except that they were added to the aCl2 aqueous solution.

Preparation of Fibers from the Anisotropic PTFE Dispersions of Examples 18-24 Oriented PTFE lmlm is readily obtained from the anisotropic PTFE dispersions by the method described below.1 The dispersion was placed in a piston-driven laboratory spinning apparatus. Introduce the nozzle (diameter 0.
5 mm) into the coagulation bath, wet spinning (introducing the fluidized dispersion below the surface of the bath) and dry jet wet spinning [dry-jejset-spinning].
(or “air-gap spi spinning”)
nning]'') technique can be successfully used, but the latter is preferred. Generally the f-gap is 1-5 m.
m range. The fibers were prepared using 5% by weight CaClt aqueous solution (*Examples 23 and 24): 1-98% sulfuric acid/water (Examples 21-24): 1-30% HCl/water (Examples 4-7).
); and ethanol (Examples 18'-20), one winding speed coagulated in a bath (100 cy in length) was generally 20 zz min without spin drawing. Cohesive fibers were obtained without further processing.

The mechanical properties of the spun main fibers made from the dispersion of Example 24 were measured at room temperature using an Instron tensile tester. The initial sample length is 1
0zz and the crosshead speed was 1°27 iv/min. Modulus (M) is 1.39/denier; tenacity (T) is 0.02 g/denier; and elongation at break (E
) was 2%. Optical microscope photo (Figure 2) and Xm
The diffraction pattern showed good alignment of PTFE molecules in the fiber direction.

Continue spinning some of the unspun a miscellaneous materials at 370°.
Heated for minutes. These #i! IIIa mechanical: M2
S, 2 g/denier; T, 0.13 g/denier; and E, 35%.

Large 44- Commercially available (E, 1. DuPont de Nemois & Co.
PTFE emulsion (43.7% spherical particles) from es+ours and Co5panyl, 25ml,
and 25 shoulders manufactured according to the method described in the text! of anisotropic PTFE emulsion (4.7% rod-shaped particles)
Mixed at 0°. The mixture is 9°5 based on the total amount of polymer.
% by weight of rod-shaped particles. 3% HCl from the mixture
Cohesive fibers were spun in (air gap spinning),
The fibers could be drawn in a continuous manner at a speed of 25 meters/min. The properties of the fibers are shown below. Fiber I
Il was sintered at 37° and fiber a2 was sintered at 370° while keeping the length constant.

1 ' 0,13 492 0,70 11502
0.43 28 1,50 292 1 pickle L! LL 20mlf) The method of Example 44 was repeated using a commercially available PTFE emulsion and an anisotropic emulsion of C7C71O. The mixture contained 5% by weight of rod-shaped particles based on the total amount of polymer. The properties of the fibers are shown below. a-fi 3
was sintered at 37° and fiber 4 was sintered at 37° while keeping the length constant.

Powerful growth Moji, Las Denier East ML (L6mu1) 3 Kamin JJ 夛胛e Pack μ discharge 3
0,08 592-- 18904
0.78 16 4.90 395 During the preparation of the mixed dispersions of Examples 44 and 45, the formation of dels was first observed. This problem can be solved by mixing at 50° or by using commonly used fluorocarbon surfactants such as CF, CO, NH, or C+z
This could be avoided by adding H2sC02N a.

The best mode presently contemplated for carrying out the present invention is as follows: ! It is presented by the detailed explanation given in Book i.

[Brief explanation of the drawing]

PIS figures 1 to 4 show reaction times of 1.30.6, respectively.
1 is a transmission electron micrograph of rod-shaped PTFE particles produced by the method of the present invention carried out for 0 and 180 minutes. FIG. 5 is an electron diffraction pattern of rod-shaped PTFE particles produced by the method of the present invention and recorded at room temperature. Figures 6 to 9 are diagrams showing anisotropic phases produced by the method of the present invention using reaction times of 5, 30, 60 and 180 minutes, respectively, and observed with a polarizing microscope at 100x magnification. FIG. 10 is an XIQ diffraction diagram of oriented PTFE fi fabric produced by the method of the present invention. Figure 11 shows the results obtained by the method of the present invention carried out with a reaction time of 60 minutes.
This is a photograph taken with the opening of a PTFE molecular polarizer. FIG. 12 is a polarized light micrograph of oriented PTFE fibers produced r) by using the method of the invention. Patent Applicant: E.I. DuPont de Nemois & Co. FIG, 3 -FtG, 5 FIG, 7 FIG, 8 FIG, 9 FIG, 1I FIG, I2

Claims (1)

[Claims] 1. Tetrafluoroethylene, or a mixture of 50 mol% or more of tetrafluoroethylene and 50 mol% or less of a comonomer copolymerizable therewith, is liberated in an aqueous medium in a substantially oxygen-free system. In a method for producing an anisotropic, liquid crystalline aqueous dispersion by group polymerization, 0.000
1 - 0.1% w/v free radical initiator, and formula RA: where R is 1) Z-(-CF_2-)x-(-CH_2CH_2-
)y, y is 0 or 1; x is 7 to 13; and Z is H, F, Cl, or Br; or 2) W-CF_2CF(W)O-(-CF_2CF(C
F_3) O-)z-CF_2CF_2-, and z is 1 to 2; and W is Cl or F; or 3) Z-(-CF_2-)x-(-CH_2-)-y, y is 0, 1 or 2; x is 8 to 13; and Z is H, F, Cl or Br; and A is -SO_3M, -COOM or -SO_3NR_2, where M is Li^ +, Na^+, K^+ or NH_4^+; R is -CxH_2x_+_1; x is from 1 to 5, in the presence of a surfactant represented by Tetrafluoroethylene or a mixture of comonomers copolymerizable with tetrafluoroethylene and up to 1 mol % thereof, ranging from the critical micelle concentration (cmc) to the total solubility of the surfactant in the polymerization medium,
Tetrafluoroethylene or tetrafluoroethylene/comonomer pressure 20-2 for 1-180 minutes at 0°C.
000 psig (138-13,800 kPa). 2. Polymerization time is about 1-120 minutes, temperature is 60-100℃
, the pressure of tetrafluoroethylene is 60-600psi
g (414-4,140 kPa), and the concentration of the initiator was 0.
005-0.020% w/v and the concentration of surfactant ranges from cmc to about 5% w/v. 3. Tetrafluoroethylene/comonomer mixture is 8
0 mol% or more of tetrafluoroethylene and 20 mol%
3. Process according to claim 2, characterized in that it consists of the following comonomers: 4. Process according to claim 3, characterized in that the mixture consists of at least 98 mol% tetrafluoroethylene and no more than 2 mol% comonomer. 5. The method according to claim 3, wherein the comonomer is vinylidene fluoride. 6. The method according to claim 4, wherein the comonomer is hexafluoropropylene. 7. The method according to claim 4, wherein the comonomer is perfluoropropyl vinyl ether. 8. The method according to claim 4, wherein the comonomer is perfluorobutylethylene. 9. The method according to claim 1, which is carried out in a batch manner. 10. The method according to claim 1, characterized in that it is carried out in a continuous manner. 11. An anisotropic liquid crystalline aqueous dispersion of polytetrafluoroethylene or tetrafluoroethylene copolymer, produced by the method according to claim 1. 12. Polytetrafluoroethylene or 50 mol% or more of tetrafluoroethylene repeating units and 50 mol%
An anisotropic liquid crystalline aqueous dispersion of a polymer selected from the following copolymers consisting of repeating units of comonomers copolymerizable with tetrafluoroethylene. 13. Claim 12, characterized in that the copolymer consists of 80 mol% or more of tetrafluoroethylene repeating units and 20 mol% or less of comonomer repeating units.
Dispersion as described in Section. 14. Dispersion according to claim 13, characterized in that the copolymer consists of at least 98 mole % tetrafluoroethylene repeat units and not more than 2 mole % comonomer repeat units. 15. A copolymer consisting of at least two phases, the uppermost phase consisting of polytetrafluoroethylene, and 50 mol% or more of repeating units of tetrafluoroethylene and up to 50 mol% of repeating units of a comonomer copolymerizable with tetrafluoroethylene. is an isotropic aqueous dispersion consisting of rod-shaped particles of a polymer selected from 1. An aqueous dispersion, characterized in that it is an anisotropic liquid crystalline aqueous dispersion of a polymer selected from copolymers consisting of repeating units of comonomers copolymerizable with ethylene. 16. The dispersion according to claim 15, wherein in each phase, the polymer consists of 80 mol % or more of tetrafluoroethylene repeating units and 20 mol % or less of comonomer repeating units. 17. In each phase, at least 98 mol% copolymer
The dispersion according to claim 16, characterized in that it consists of tetrafluoroethylene repeating units and not more than 2 mole % of comonomer repeating units. 18. Anisotropy of a polymer selected from polytetrafluoroethylene and a copolymer consisting of 50 mol% or more of repeating units of tetrafluoroethylene and 50 mol% or less of repeating units of a comonomer copolymerizable with tetrafluoroethylene. an aqueous dispersion comprising a mixture of liquid crystalline aqueous dispersions, characterized in that up to 95% by weight of the aqueous polytetrafluoroethylene dispersion, based on the total weight of the polymer, consists essentially of spherical particles of polytetrafluoroethylene. . 19. Claim 1, characterized in that the copolymer consists of 80 mol% or more of tetrafluoroethylene repeating units and 20 mol% or less of comonomer repeating units.
Dispersion according to item 8. 20. The dispersion of claim 19, wherein the copolymer consists of at least 98 mole percent tetrafluoroethylene repeat units and no more than 2 mole percent comonomer repeat units. 21. Fibers of a polymer selected from polytetrafluoroethylene and a copolymer consisting of 50 mol% or more of repeating units of tetrafluoroethylene and 50 mol% or less of repeating units of a comonomer copolymerizable with tetrafluoroethylene. In the manufacturing method, a polymer selected from polytetrafluoroethylene and a copolymer consisting of 50 mol% or more of repeating units of tetrafluoroethylene and 50 mol% or less of repeating units of a comonomer copolymerizable with tetrafluoroethylene. A dilute aqueous solution of calcium chloride or magnesium, an anisotropic liquid crystalline aqueous dispersion of
1-98% H_2SO_4/water, 1-30% HCl/water, ethanol for dispersions prepared in the presence of surfactants containing terminal -SO_3 groups, or terminal -CO
C__1_6H_3_3N(CH_3)_3 for dispersions prepared in the presence of surfactants containing O groups.
A method characterized by extrusion into an aqueous solution of ^+Br and accumulation of the fibers produced in this way. 22. Claim 2, characterized in that the copolymer consists of 80 mol% or more of tetrafluoroethylene repeating units and 20 mol% or less of comonomer repeating units.
The method described in Section 1. 23. The method of claim 22, wherein the copolymer comprises at least 98 mole percent tetrafluoroethylene repeat units and no more than 2 mole percent comonomer repeat units. 24, the concentration of calcium chloride or magnesium chloride is 2
-10% by weight Claim 2
The method described in Section 1. 25. The method of claim 24, wherein the concentration is about 5% by weight. 26. The method according to claim 21, characterized in that a wet spinning method is used. 27. The method according to claim 21, characterized in that a dry jet wet spinning method is used. 28. Made by a non-sintering process, from polytetrafluoroethylene or a copolymer consisting of not less than 50 mol% of repeating units of tetrafluoroethylene and not more than 50 mol% of repeating units of a comonomer copolymerizable with tetrafluoroethylene. A white fiber characterized by: 29. In an anisotropic liquid crystalline aqueous dispersion, an aqueous polytetrafluoroethylene dispersion consisting essentially of spherical particles of polytetrafluoroethylene is added to the anisotropic liquid crystalline aqueous dispersion in an amount of up to 9
22. A method according to claim 21, characterized in that up to 5% by weight is mixed. 30. A method according to claim 29, characterized in that the mixed dispersion contains from 91.5 to 95% by weight of an aqueous polytetrafluoroethylene dispersion consisting essentially of spherical particles of polytetrafluoroethylene. . 31. The method of claim 29, wherein the dispersion of substantially spherical particles of polytetrafluoroethylene comprises a fluorocarbon surfactant. 32, the surfactant is C_7F_1_73CO_2NH
32. The method according to claim 31, characterized in that:_4. 33, the surfactant is C_1_2, H_2_5, CO_
32. The method according to claim 31, wherein 2Na is used.