JPH05301294A - Aqueous extrusion auxiliary agent for molding of polytetrafluoroethylene - Google Patents

Abstract

PURPOSE:To provide an aqueous extrusion auxiliary agent for molding of polytetrafluoroethylene(PTFE) which is safe, easily moldable and also superior in properties of a molded product. CONSTITUTION:This is an aqueous extrusion auxiliary agent for molding of PTFE containing at least 1wt.% fluorine ion surface active agent. With this construction, since the agent is an aqueous series, it is safe and can be extracted and removed with water and explosion-proof equipments for ignition or explosion become unnecessary. Then since the auxiliary agent has favorable mixing properties or affinity, smooth extrusion molding can be performed and a molded product which is colorless and has a favorable external appearance is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based extrusion aid for paste extrusion molding of polytetrafluoroethylene (PTFE) and a method for producing a polytetrafluoroethylene molded article using the same.

[0002]

2. Description of the Related Art PTFE has excellent properties such as excellent heat resistance and chemical resistance, high electric insulation and low friction, but its high melt viscosity makes it possible to use a conventional plastic molding method even if heated above its melting point. Molding is extremely difficult.

As one of the methods for molding such a PTFE, there is a method of using a paste extrusion method using a fine powder of PTFE and a calender molding method. That is, a PTFE aqueous dispersion obtained by emulsion polymerization of tetrafluoroethylene (TFE) is coagulated and dried. A so-called fine powder is mixed with an appropriate organic solvent to form a paste-like compound, which is previously compressed at a constant pressure. Preform. The obtained billet is put into a cylinder of an extruder and pressurized to plastically deform the particles and extrude through a narrow hole to obtain a continuous unfired rod having a predetermined shape. The paste extrusion method is a method in which an organic solvent is volatilized by heating from the rod and baked to obtain a product, and the calendar molding method is a method in which a product is rolled into a sheet.

In the latter case, a PTFE film having excellent transparency can be obtained by rolling with a hot roll to a sheet having a predetermined thickness before the organic solvent is volatilized, extracting the solvent, drying and then sintering. Mostly PTF excluding organic auxiliary agent before firing
E Used as unbaked tape (raw tape).

The organic solvent added to this fine powder is called an extrusion aid. In the paste extrusion method, solvent naphtha, etc., which completely evaporates without leaving carbon even when heated to a firing temperature of about 400 ° C., is used. In the calender molding method, white oil having a relatively high viscosity and excellent lubricity is used.

The type and amount of the auxiliary agent influences the extrusion pressure, and the addition amount of these auxiliary agents is empirically known for each extrusion condition.

In the paste extrusion method, the auxiliary agent is heated in the firing process and the auxiliary agent is volatilized to form steam, which is apt to ignite or explode. Therefore, the molding machine requires explosion-proof equipment and exhaust equipment.

Further, a facility for extracting and drying the auxiliary agent is required at the time of calender molding, but as the extraction solvent, halides such as trichlorethylene, perkrene and freon which are not inflammable are used. However, due to environmental problems, CFC regulations, etc., these are becoming unusable.

On the other hand, it has been proposed to use an aqueous medium containing a surfactant as an extrusion aid as an improvement of the PTFE paste extrusion molding method in which a large amount of filler is contained (Japanese Patent Laid-Open No. 1-306219). This publication proposes to use an aqueous medium containing a fluorosurfactant as an extrusion aid, and particularly PTFE containing a nonionic surfactant.
The use of dispersion has been specifically examined. According to this method, it is expected that the above-mentioned problems of the work environment and the improvement of safety can be expected.

[0010]

However, the method using the PTFE dispersion containing a nonionic surfactant has a drawback that a molded article obtained by the influence of the surfactant is colored. Further, JP-A-1-306219 does not specifically exemplify what kind of fluorine-based surfactant can be used in addition to the PTFE dispersion.

There are a wide variety of fluorosurfactants, and it is not possible to use any fluorosurfactant to paste extrude and to manufacture a molded product comparable to the conventional one. For example, depending on the structure of the lipophilic base part or the structure of the hydrophilic base part, the mixing and dispersibility with the PTFE powder or the affinity (holding property) may become poor, and the appearance of the obtained PTFE molded product may be poor. However, there are cases where even continuous extrusion cannot be performed. For example, when paste extrusion molding is performed using an aqueous medium containing only the fluorine-based nonionic surfactant contained in the PTFE dispersion, there is a problem in mixing with the PTFE powder and retention of the auxiliary agent, Extrusion could not be done.

[0012] These problems naturally occur when extrusion molding a paste in which a filler is mixed with PTFE in order to improve the mechanical properties of the molded product. That is,
When the filler is mixed, a problem arises not only in the mixing dispersibility and affinity of the PTFE powder and the extrusion aid, but also in the mixing dispersibility and affinity of the filler itself and the aid.

The present invention provides a water-based extrusion aid which has moldability comparable to that of conventional organic extrusion aids and has excellent properties of the obtained molded product.

[0014]

The water-based extrusion aid for PTFE extrusion of the present invention contains 1 to 50% by weight of a fluorinated ionic surfactant.

The water-based extrusion aid for the PTFE paste extrusion of the present invention contains a fluorinated ionic surfactant, and particularly an anionic surfactant.

As a specific example of the fluorinated anionic surfactant, a salt of a carboxylic acid having a fluoroalkyl group or a salt of a sulfonic acid having a fluoroalkyl group (hereinafter referred to as a specific fluorinated surfactant) is used. be able to.

The fluoroalkyl group bonded to the carboxylate or sulfonate is not particularly limited, but from the viewpoint of solubility in an aqueous medium, it preferably has 3 to 9 carbon atoms, more preferably carbon atoms. The number is from 7 to 8 and may have an ether bond or a branched chain.

Specific examples of the above-mentioned specific fluorine-containing surfactant include, for example, ω-hydrofluoropentanoate, perfluoroheptanate, perfluorooctanoate, perfluorononanoate and perfluorodecanoate. Linear fluoroalkylcarboxylic acid salts such as; ether bonds and side chains such as perfluoro-3,6-dioxy-2,5-dimethylnonanoate, perfluoro-3-oxy-2-methyl-hexanoate And fluoroalkyl sulfonates such as perfluorooctyl sulfonate and the like, and perfluorooctanoate and perfluorononanoate are particularly preferable.

Examples of these salts include ammonium salts or alkali metal salts such as potassium salts and sodium salts, with ammonium salts being particularly preferred.

Generally, there are few fluorine-containing surfactants which are dissolved in water by 6% by weight or more, but the specific fluorine-containing surfactant is dissolved by 10% by weight or more. Moreover, since it is sublimated by heating to 130-250 ℃, it is baked (around 400 ℃).
It does not remain in the molded product later.

The extrusion aid of the present invention is obtained by dissolving a specific fluorine-containing surfactant in water in an amount of 1 to 50% by weight, preferably 6 to 15% by weight. When the amount of the specific fluorine-based surfactant is small, the auxiliary agent is not sufficiently dispersed in the PTFE fine powder or the filler to be mixed if necessary,
The plastic deformation of the fine powder is uneven during extrusion. When such unevenness occurs, the mechanical strength of that portion is greatly reduced. On the other hand, if the amount is too large, it becomes difficult to remove the specific fluorine-based surfactant and it is economically disadvantageous.

An organic solvent may be further mixed with the extrusion aid. When the organic solvent is mixed, the extrusion pressure is stabilized, the dispersibility of the PTFE fine powder or the filler and the auxiliary agent is further improved, and the width of the sheet is increased during calendar molding. Examples of miscible organic solvents include solvent naphtha, white oil, petroleum ether, ketone-based solvents such as acetone and methyl ethyl ketone, methyl alcohol, ethyl alcohol,
Examples include alcohol solvents such as isopropyl alcohol, ethylene glycol, glycerin, and ether solvents such as ethylene glycol monobutyl ether.
Water-soluble alcohols such as isopropyl alcohol and ethyl alcohol are particularly preferable. The mixing amount is preferably such that it accounts for 5 to 50% by volume, preferably 5 to 30% by volume of the water-based extrusion aid. If the amount of the organic solvent is too small, the mixing effect cannot be obtained, and if the amount is too large, the advantages of the water-based auxiliary agent such as nonflammability and easy water extraction are impaired.

The PTFE fine powder as a molding material can be obtained by TFE alone or by emulsion polymerization of TFE and 5% by weight or less of a copolymerization component. Examples of the copolymerization component include hexafluoropropylene, chlorotrifluoroethylene, ω-hydroperfluorobutene, perfluoromethyl vinyl ether, perfluoropropyl vinyl ether and the like. Further, the fine PTFE powder obtained by the suspension polymerization method, the solution polymerization method, or the like may be blended to such an extent that the extrusion molding operation is not affected.

The PTFE fine powder may contain a filler. By mixing the filler, the mechanical properties (wear resistance, compressive strength, cold flow resistance) and electrical properties (electrostatic removal) of the molded product are improved. The filler may be mixed either by uniformly mixing the filler with the PTFE dispersion and then co-coagulating it, or by adding the filler when mixing the PTFE fine powder with the extrusion aid. Examples of the filler used include glass, glass fiber, graphite, bronze, molybdenum disulfide, carbon powder, carbon fiber,
Inorganic powder such as metal oxide, polyimide, polyamide imide, polyphenylene oxide, aromatic polyester,
Organic powders such as polyetherketone, polyethersulfone, polyetherimide, polysulfone, polyphenylene sulfide, and polycarbonate are listed. The average particle size of the filler is 1 to 100 μm, preferably 5
˜20 μm, and may be mixed in an amount of about 5 to 40% by weight of the extrusion paste.

Next, the paste extrusion molding method and calendar molding method using the water-based extrusion aid of the present invention will be described.

The extrusion paste is a water-based extrusion aid containing PT.
20-40 parts by weight per 100 parts by weight of FE fine powder,
Preferably, 25 to 30 parts by weight is added, and when the filler is mixed, 20 to 40 parts by weight are added per 100 parts by weight of the PTFE fine powder containing the filler, and the mixture is mixed by a tumbler shaker mixer or the like. Since the specific fluorine-based surfactant used in the present invention has good sublimability and water-extractability, it can be used in both the paste extrusion method and the calender molding method.

The obtained extruding paste is extruded by a conventionally known paste extruding machine to prepare unfired molded articles such as tubes, rods and pipes. Extrusion temperature is usually
The temperature is 10 to 80 ° C, preferably 20 to 50 ° C. In the paste extrusion method, the unfired molded product obtained is heated and dried at 150 to 250 ° C to evaporate water and a specific fluorine-based surfactant, if necessary, an organic solvent, and then fired at 350 to 400 ° C. To do. Since the water-based extrusion aid of the present invention is nonflammable, the explosion-proof equipment and large-scale exhaust equipment that have been conventionally required become unnecessary. Also, specific fluorosurfactants are about 130-250
Since it sublimates around ℃, it does not remain in the molded product.

In the calendering method, as in the conventional method, the paste-extruded unsintered rod is rolled with a calender roll once or twice or more to form a sheet, film or tape before the auxiliary agent evaporates. The temperature of the calender roll is 10 to 80 ° C, preferably 30 to 70 ° C. Although the extrusion aid is extracted from the obtained unsintered sheet, etc., since the present invention uses an aqueous aid, extraction with an aqueous solvent is possible, which makes it possible to reduce the cost of the extraction solvent and achieve safety. .. Examples of the extraction solvent include water, methyl alcohol, ethyl alcohol, acetone and the like, and water is particularly preferable from the viewpoint of being inexpensive and safe.

The molded product obtained by the production method of the present invention is, for example, an electric wire for wiring of aircraft, rockets, missiles, wiring of transformers for electric power transmission and distribution, wiring of electric motors, various wiring in the electronic industry sector, and thermal power generation by the paste extrusion method. Electric wire coatings that can be used for wiring in high temperature areas near electric power furnaces and vacuum tubes, wiring in the chemical industry that is subject to strong chemicals, etc .; fuel transport pipes for jets and rockets, high temperature corrosion in chemical plants and nuclear plants Fluid transport pipes, fluid transport pipes that are resistant to contamination such as food and chemicals, brake hoses for hydraulic control devices, hoses or tubes such as insulating tubes for electronic devices; processing materials for pumps and valve parts, terminals and bushings, etc. A molded product such as a round bar can be obtained as a processing material for the insulator, and the unfired rod can be used as it is or by stretching it to make a packing material for valves. Sealing material such as a gasket will be obtained. The unfired tape (raw tape) obtained by the calendering method shrinks about 30% in the rolling direction during firing, so it is useful as an insulation coating for electrical wires and coils, as a connection / repair material, or when fired while stretched. Alternatively, an insulating film or a porous film can be used.

Since the mixture of the fillers improves the mechanical and electrical characteristics as described above, in addition to the above products, inner casings of cable conduits, sliding members such as bearings and pads, packing materials, and sealing materials. , Wire coating reinforcement,
It is useful as an antistatic agent or the like, or as an unfired or fired tape or film containing a filler, a shrinkable tube, a porous body or the like.

[0031]

EXAMPLES Next, the water-based extrusion aid of the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Example 1 Ammonium salt of perfluorononanoic acid (anionic type)
Was dissolved in water to form an aqueous solution having a concentration of 10% by weight, and isopropyl alcohol (IPA) was added thereto in an amount of 10% by volume to prepare an aqueous extrusion aid. 29.1 parts by weight of this auxiliary agent was added to 100 parts by weight of PTFE fine powder and aged for 20 hours at room temperature to prepare an extrusion paste (auxiliary agent mixed paste).

10 t of this paste manufactured by Shimadzu Corporation
Universal testing machine (cylinder diameter of extrusion die: 30mm, nozzle diameter: 5mm, ratio of cylinder cross section / nozzle cross section:
It was extruded at 36/1 and an extrusion speed of 20 mm / min) to produce an unfired rod. The total extrusion load was 350 kg, which was stable.

The green rod obtained is subsequently subjected to 60 at 250 ° C.
It was heated for 1 minute to remove the extrusion aid, and then baked at 365 ° C. for 30 minutes to obtain a rod-shaped PTFE fired molded article.

In this example, the extruding paste was examined for compatibility with the PTFE powder and auxiliary agent retention in the following manner, and the appearance and the degree of coloring of the molded product after firing were visually observed.

The results are shown in Table 1.

(Mixability) 80 g of PTFE fine powder is put into a glass standard bottle having a capacity of 200 cc, and a predetermined amount of extrusion aid is added. After tumbling by hand for about 3 minutes, visually observe the mixed state of the powder and the auxiliary agent.

The evaluation was performed visually according to the following criteria.

A: Good (the powder is dry) B: Generally good (The powder is smooth, but some small lumps are produced) C: Somewhat nonuniform (dango-like lumps are produced) D : Poor (Auxiliary agent concentrates in one part and does not spread all over) (Auxiliary agent retention) PTFE fine powder or PTFE fine powder with filler is mixed with an extrusion auxiliary agent to prepare a paste. It is loaded into the extrusion die of the tester, preformed at low pressure (total load 60 kg), and then extruded at a predetermined speed. The presence or absence of leaching of the auxiliary agent from the mold during preforming and extrusion is visually observed.

The evaluation was performed according to the following criteria.

A: No leaching B: Little leaching during extrusion (no leaching during preforming) C: Some leaching during extrusion (no leaching during preforming) D: Leaching out during preforming Example 2 An aqueous extrusion aid was prepared in the same manner as in Example 1 except that a 10 wt% aqueous solution of potassium salt of perfluorononanoic acid (anionic type) was used as the fluorinated ionic surfactant. Prepared,
After preparing an extrusion paste in the same manner as in the same example, paste extrusion and firing were carried out to obtain a PTFE molded product.

Table 1 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 1.

Example 3 Perfluoro-3,6 as a fluorinated ionic surfactant
A water-based extrusion aid was prepared in the same manner as in Example 1 except that a 10% by weight aqueous solution of ammonium salt of dioxy-2,5-dimethylnonanoic acid (anionic type) was used, and extruded in the same manner as in Example 1. A paste was prepared, and the paste was extruded and fired to obtain a PTFE molded product.

The results of examining the properties of the paste for extrusion and the molded product in the same manner as in Example 1 are shown in Table 1.

Examples 4 to 5 As the fluorinated ionic surfactant, a 15 wt% aqueous solution (Example 4) of ammonium salt of perfluorooctanoic acid (anionic type) and a 7 wt% aqueous solution (Example 5) were used. Otherwise, a water-based extrusion aid was prepared in the same manner as in Example 1, and an extrusion paste was prepared in the same manner as in the same example.
Paste extrusion and firing were performed to obtain a PTFE molded product.

Table 1 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 1.

Example 6 An aqueous extrusion aid was prepared in the same manner as in Example 1 except that a 10% by weight aqueous solution of ammonium salt of perfluorooctylsulfonic acid was used as the fluorinated ionic surfactant.
After preparing an extrusion paste in the same manner as in the same example, paste extrusion and firing were carried out to obtain a PTFE molded product.

Table 1 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 1.

Example 7 Example 1 except that only a 10% by weight aqueous solution of ammonium salt of perfluorooctanoic acid was used as an aqueous extrusion aid.
A paste for extrusion was prepared in the same manner as above, and the paste was extruded and fired to obtain a PTFE molded product.

Table 1 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 1.

Example 8 10% by weight of ammonium salt of perfluoroundecanoic acid
Using a water-based extrusion aid prepared by adding 5% by volume of isopropyl alcohol to an aqueous solution, an extrusion paste was prepared in the same manner as in Example 1, and paste extrusion and firing were carried out to obtain a PTFE molded article.

Table 1 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 1.

Example 9 An extrusion paste was prepared in the same manner as in Example 1 except that an aqueous extrusion aid prepared by adding 20% by volume of isopropyl alcohol to a 3% by weight aqueous solution of ammonium salt of perfluorooctanoic acid was prepared. Paste extrusion and firing were performed to obtain a PTFE molded product.

Table 1 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 1.

[0055]

[Table 1]

Comparative Example 1 Extrusion paste was prepared in the same manner as in Example 1 except that 10% by volume of isopropyl alcohol was added to a 10% by weight aqueous solution of the following fluorine-based nonionic surfactant as an extrusion aid. Was prepared, and paste extrusion and firing were performed to obtain a PTFE molded product.

Nonionic surfactant

[0058]

[Chemical 1]

(Wherein R _f is a C ₇ F ₁₅ fluoroalkyl group, n and m are integers of 1 to 20) The properties of the extrusion paste and the molded product were examined in the same manner as in Example 1 and the results are shown. It shows in Table 2.

Comparative Example 2 Using the 3 wt% aqueous solution of the fluorine-based nonionic surfactant shown in Comparative Example 1 as an aqueous extrusion aid, an extrusion paste was prepared in the same manner as in Example 1, and the paste was extruded and fired. Then, a PTFE molded product was obtained.

Table 2 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 1.

Comparative Example 3 Using a 0.5% by weight aqueous solution of ammonium salt of perfluoroundecanoic acid as an aqueous extrusion aid, a paste for extrusion was prepared in the same manner as in Example 1, and the paste was extruded and fired to obtain a PTFE molded article. I got it.

Table 2 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 1.

Comparative Example 4 0.5% by weight of ammonium salt of perfluorooctanoic acid
Using the aqueous solution as an aqueous extrusion aid, an extrusion paste was prepared in the same manner as in Example 1, and the paste was extruded and fired to obtain a PTFE molded article.

Table 2 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 1.

Comparative Example 5 0.5% by weight of ammonium salt of perfluorooctanoic acid
Using a water-based extrusion aid prepared by adding 10% by volume of isopropyl alcohol to an aqueous solution, an extrusion paste was prepared in the same manner as in Example 1, and paste extrusion and firing were carried out to obtain a PTFE molded product.

Table 2 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 1.

Comparative Example 6 An attempt was made to prepare an extrusion paste by using pure water.
Poor dispersibility and no extrudable paste was obtained.

[0069]

[Table 2]

Example 10 The unfired rod obtained by extruding the paste in Example 1 was rolled on a calender roll (diameter 300 mm) maintained at 40 ° C. before the extrusion aid was dried, and the thickness was 0.1 m.
It was a sheet of m. Then, the extrusion aid was extracted with water and baked at 365 ° C. for 3 minutes to obtain a sheet-shaped molded product.

The sheet width after the calendering, the tensile strength (rolling direction) of the rolled unsintered molded product, and the coloring after the sintering were examined.

The results are shown in Table 3.

(Tensile Strength) According to JIS K 6885 “Tape of tetrafluoroethylene resin unsealed tape for sealing”.

Examples 11 to 14 Calender molding and firing were carried out in the same manner as in Example 10 except that the unsintered rods obtained by paste extrusion in Examples 2 to 5 were used for calender molding to obtain molded products. I got it.

Table 3 shows the results of examining the sheet width after calendering, the tensile strength (rolling direction) of the rolled unfired molded article, and the coloring after firing in the same manner as in Example 10.

Comparative Example 7 A molded product was obtained by calendering and calcining in the same manner as in Example 10 except that the unsintered rod obtained by extruding the paste in Comparative Example 1 was used for calendering.

The sheet width after calendering, the tensile strength (rolling direction) of the rolled unfired molded article, and the coloration after firing were examined in the same manner as in Example 10 and the results are shown in Table 3.

[0078]

[Table 3]

Example 15 An ammonium salt of perfluorooctanoic acid (anionic type) was dissolved in water to prepare an aqueous extrusion aid having a concentration of 10% by weight. 24 parts by weight of this auxiliary agent was added to 100 parts by weight of PTFE fine powder containing 15% by weight of glass fiber powder, and aged for 20 hours at room temperature to prepare an extrusion paste (auxiliary agent mixed paste).

10 t of this paste manufactured by Shimadzu Corporation
Extruded with a universal testing machine (cylinder diameter of extrusion die: 25.4 mm, nozzle diameter: 2.54 mm, ratio of cross-sectional area of cylinder section / nozzle section: 100/1, extrusion speed of 20 mm / min) to produce unfired rod did. The total extrusion load was 630 kg, which was stable.

The obtained unsintered rod was subsequently heated at 250 ° C. to remove the extrusion aid, and then sintered at 365 ° C. for 3 minutes to obtain a rod-shaped PTFE sintered molded product containing a filler.

In this example, the extruding paste was examined for its compatibility with the PTFE powder containing the filler and its ability to retain the auxiliary agent in the following manner, and the appearance and the degree of coloring of the molded article after firing were visually observed.

The results are shown in Table 4.

Example 16 26 parts by weight of the water-based auxiliary agent used in Example 15 was added to 100 parts by weight of PTFE fine powder containing 20% by weight of aromatic polyester (Econol registered trademark manufactured by Sumitomo Chemical Co., Ltd.) powder. Except that after preparing a paste for extrusion in the same manner as in Example 15, paste extrusion and firing is performed,
A PTFE molded product containing a filler was obtained.

Table 4 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 15.

Example 17 An extrusion paste was prepared in the same manner as in Example 15 except that 38 parts by weight of the water-based auxiliary agent used in Example 15 was added to 100 parts by weight of PTFE fine powder containing 5% by weight of carbon powder. Preparation, paste extrusion and firing were carried out to obtain a PTFE molded product containing a filler.

Table 4 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 15.

[0088]

[Table 4]

Comparative Example 8 An extrusion paste was prepared in the same manner as in Example 15 except that 17 parts by weight of the oil-based auxiliary agent Isopar E (manufactured by Exxon) was added as an extrusion auxiliary agent, and the paste was extruded and fired. A PTFE molded product containing a filler was obtained.

Table 5 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 15.

Comparative Example 9 A paste for extrusion was prepared in the same manner as in Example 15 except that 18 parts by weight of the extrusion aid used in Comparative Example 8 was added, and the paste was extruded and fired, and PTFE containing a filler was added.
I got a molded product.

Table 5 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 15.

Comparative Example 10 An extrusion paste was prepared in the same manner as in Example 15 except that 24 parts by weight of the extrusion aid used in Comparative Example 8 was added, the paste was extruded and fired, and PTFE containing a filler was added.
I got a molded product.

Table 5 shows the results of examining the properties of the extrusion paste and the molded product in the same manner as in Example 15.

[0095]

[Table 5]

As is clear from the comparison between the results in Tables 4 and 5, the water-based extrusion aid of the present invention is inferior in properties to conventional oil-based auxiliaries. Therefore, according to the present invention, it is possible to carry out the extrusion molding similar to the conventional one completely and with a significantly reduced influence on the environment.

[0097]

According to the water-based extrusion aid for PTFE molding of the present invention, there is no danger of ignition or explosion, explosion-proof equipment and large-scale exhaust equipment are unnecessary, and the working environment and safety are improved. Further, since it has good compatibility with the PTFE powder and the filler, continuous extrusion molding is possible, and since the affinity with the PTFE powder is good, the extrusion pressure is stable. Furthermore, the auxiliary agent does not completely evaporate during firing and does not remain in the molded article, and can be extracted with water in the calender molding method.
An excellent molded product can be obtained safely and at low cost.

[Procedure amendment]

[Submission date] January 28, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

10. A water-based extrusion aids according to claim 8 or 9, wherein not including polytetrafluoroethylene filler.

11. Aqueous extrusion aid according to claim 8 or 9, wherein the polytetrafluoroethylene contains a filler.

12. The method according to claim 1, 2, 3, 4, 5, 8 or
Preparation of polytetrafluoroethylene molded article of baking After paste extruded port re polytetrafluoroethylene powder using a 9 Symbol mounting aqueous extrusion aid.

13. The method of claim 1, 2, 3, 4, 8 or
The Po Li polytetrafluoroethylene powder was rolled After paste extrusion molding using a 9 Symbol mounting aqueous extrusion aid, then preparation of polytetrafluoroethylene molded article of extracting and removing the aqueous extrusion aid in an aqueous extraction solvent.

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Claims (12)

[Claims] 1. A water-based extrusion aid for paste extrusion of polytetrafluoroethylene containing 1 to 50% by weight of a fluorinated ionic surfactant. 2. The water-based extrusion aid according to claim 1, wherein the fluorinated ionic surfactant is a fluorinated anionic surfactant. 3. The water-based extrusion aid according to claim 2, wherein the fluorine-based anionic surfactant is a carboxylate having a fluoroalkyl group or a sulfonate having a fluoroalkyl group. 4. The water-based extrusion aid according to claim 3, wherein the fluoroalkyl group has 3 to 9 carbon atoms. 5. The water-based extrusion aid according to claim 1, 2, 3 or 4, wherein polytetrafluoroethylene does not contain a filler. 6. The water-based extrusion aid according to claim 1, 2, 3 or 4, wherein polytetrafluoroethylene contains a filler. 7. The method according to claim 1, further comprising an organic solvent.
The water-based extrusion aid according to 2, 3, 4, 5 or 6. 8. A water-based extrusion aid for paste extrusion of polytetrafluoroethylene containing 1 to 50% by weight of an ammonium salt of a carboxylic acid having a fluoroalkyl group having 7 to 8 carbon atoms. 9. The water-based extrusion aid according to claim 8, wherein the polytetrafluoroethylene does not contain a filler. 10. The water-based extrusion aid according to claim 8, wherein the polytetrafluoroethylene contains a filler. 11. The method according to claim 1, 2, 3, 4, 5, 6, 7,
A method for producing a polytetrafluoroethylene molded product, which comprises using a water-based extrusion aid as described in 8, 9, or 10 to paste-extrude a filler-containing polytetrafluoroethylene powder and then firing it. 12. The method according to claim 1, 2, 3, 4, 5, 6, 7,
Polytetrafluoroethylene molded product obtained by paste-extruding a filler-containing polytetrafluoroethylene powder using the water-based extrusion aid according to 8, 9 or 10 and then rolling and then extracting and removing the water-based extrusion aid with an aqueous extraction solvent. Manufacturing method.