TW201943741A - Polytetrafluoroethylene aqueous dispersion - Google Patents

Abstract

Provided is a polytetrafluoroethylene (referred to hereinafter as "PTFE") aqueous dispersion that has exceptional long-term dispersion stability, does not allow the PTFE in a final product to separate even when added to a liquid material such as a paint, can succeed in imparting the functions of PTFE in a desired final form, and has exceptional productivity economically. This PTFE aqueous dispersion is characterized by containing 10-70% by mass of fine particles of PTFE that have a primary particle diameter of 0.03-0.3 [mu]m and a number-average molecular weight Mn of 10,000-30,000, also containing 0.5-20% by mass of a dispersant relative to the fine particles of PTFE, the foam volume ratio being less than 10 vol%, and the average particle diameter by dynamic light scattering being less than 300 nm.

Description

Teflon aqueous dispersion

The present invention relates to an aqueous polytetrafluoroethylene dispersion, which can stably disperse polytetrafluoroethylene (PTFE) particles for a long period of time, has excellent handling, and can impart special functions of PTFE such as water repellency, oil repellency, electrical characteristics, heat resistance, and electrical insulation. Properties, low dielectric properties, low friction properties, non-adhesiveness, weather resistance, flame retardancy, etc .; and water-based compositions that use them to impart polytetrafluoroethylene functionality.

Polytetrafluoroethylene (hereinafter sometimes referred to as "PTFE") is water-repellent, oil-repellent, electrical, heat-resistant, electrically insulating, low-dielectric, low-friction, non-adhesive, weather-resistant, and flame-resistant Such excellent materials have been used in electronic equipment, sliding materials, automobiles, and kitchen supplies.
Polytetrafluoroethylene based on these characteristics is used as a fine powder added to various resin materials or rubbers, adhesives, lubricants or greases, printing inks or coatings, etc., for the purpose of improving product characteristics.

For example, polytetrafluoroethylene fine particles (PTFE particles) are usually prepared by emulsion polymerization in the presence of water, a polymerization initiator, a fluorinated emulsifier, and a stabilizer such as paraffin. Produced by polymerizing and obtaining an aqueous dispersion containing PTFE particles, and then concentrating, agglomerating, and drying (for example, refer to Patent Document 1).

In general, in order to provide PTFE particles with a liquid material such as a coating material to impart the function of PTFE, the PTFE particles must be dispersed in the liquid material. However, since it is not easy to wet the PTFE particles with the liquid material again, the liquid material is generally prepared in the state of an aqueous dispersion in which a stabilizer is added after polymerization.
In this conventional PTFE aqueous dispersion, since the particles tend to be fibrillated, the particles are slightly aggregated by shearing. In addition, in order to continue the dispersion state during the emulsion polymerization, there is a problem that the dispersion stability is poor, and a hard mass is formed in the container over time.

Conventionally, as a means to eliminate such problems, the following methods are known, for example
1) An aqueous polytetrafluoroethylene dispersion, characterized in that it contains PTFE particles with an average particle size of 0.1 to 0.5 μm obtained by emulsification polymerization in an amount of 5 to 30% by mass, and 1 to 12 for PTFE Mass% non-ionic surfactant with characteristic structure and polyethylene oxide with an average molecular weight of 100,000-2 million for PTFE (for example, refer to Patent Document 2),
2) A method for producing a low-molecular-weight polytetrafluoroethylene aqueous dispersion, which is characterized by containing 10 to 70% by mass of polytetrafluoroethylene fine particles having an average particle diameter of 0.1 to 0.5 μm and an average molecular weight of 700,000 to 3 million, and A polytetrafluoroethylene aqueous dispersion having a pH of 6.0 to 13.0 is irradiated with a gamma ray of 2 to 100 kGy (for example, refer to Patent Document 3),
3) A polytetrafluoroethylene aqueous dispersion composition, characterized in that it contains 30 to 65% by weight of polytetrafluoroethylene fine particles obtained by emulsion polymerization, and 2 to 12% by weight of polytetrafluoroethylene is selected from the group consisting of At least one non-ionic surfactant having an average molecular structure represented by specific formulae (1) and (2) and an average molecular weight of 100,000 to 2 million for polytetrafluoroethylene of 0.01% by weight or more and less than 1% by weight Polyethylene oxide is an essential component (for example, refer to Patent Document 4).

However, the dispersion stability of the aqueous PTFE dispersions described in the above-mentioned Patent Documents 2 to 4 all originate from the dispersion state during emulsion polymerization, so they settle for a long time, and there is a problem that stirring is necessary for redispersion. In addition, when mixing liquid materials such as paints, the PTFE is separated in the final product, which makes it a design limitation and poorly usable.
In addition, in order to eliminate sedimentation, it is considered to strengthen the dispersion stability by a mechanical dispersion treatment. However, the PTFE aqueous dispersions described in the aforementioned Patent Documents 2 to 4 can suppress fibrillation due to friction, but are mechanically dispersed. The suppression of fibrillation is not sufficient, and the current situation is that the dispersion stability cannot be enhanced by mechanical dispersion treatment.
In addition, among the low-molecular-weight PTFE microparticles used in general additive applications, although dispersion stability enhancement of mechanical dispersion treatment can be achieved, it is difficult to completely wet the PTFE microparticles with water, so the remaining air bubbles are caused by mechanical dispersion treatment. It has the disadvantages of expansion due to heat, causing a rise in pressure in the device, and the like. In addition, when the residual air bubbles are expanded, the surface of the once-wet PTFE fine particles is dried, and the dispersibility is deteriorated. Therefore, it is impossible to make full use of the original ability of the device to manufacture, and it is difficult to control the quality.

[Prior technical literature]

Patent Document 1: Japanese Patent Application Publication No. 2012-92323 (Scope of patent application, examples, etc.)
Patent Document 2: Japanese Patent Application Laid-Open No. 2006-169448 (Scope of Patent Application, Examples, etc.)
Patent Document 3: Japanese Patent Application Laid-Open No. 2006-63140 (Scope of Patent Application, Examples, etc.)
Patent Document 4: Japanese Patent Laid-Open No. 2000-198899 (Scope of patent application, examples, etc.)

[Questions to be Solved by the Invention]

The present invention is directed to the above-mentioned past problems and current conditions. In order to eliminate these problems, the purpose is to provide an aqueous PTFE dispersion, which has excellent long-term dispersion stability, and does not separate PTFE inside the final product even when added to liquid materials such as coatings. It can realize the function conferring of PTFE in the desired final form, and it has economically and excellent productivity.

[Means to solve the problem]

As a result of active review by the present inventors in response to the above-mentioned conventional problems, it has been found that the polytetrafluoroethylene microparticles having a primary particle diameter of 0.03 to 0.3 μm and a number average molecular weight Mn of 10,000 to 30,000 are contained in a specific amount. Tetrafluoroethylene fine particles contain a specific amount of dispersant, so that the foam volume ratio does not reach a specific value%, and the average particle diameter obtained by dynamic light scattering method does not reach a specific value, to obtain a polytetrafluoroethylene aqueous dispersion, etc. for the above purpose, Thus, the present invention has been completed.

That is, the polytetrafluoroethylene aqueous dispersion of the present invention is characterized by containing 10 to 70% by mass of polytetrafluoroethylene fine particles having a primary particle diameter of 0.03 to 0.3 μm and a number average molecular weight Mn of 10,000 to 30,000. The polytetrafluoroethylene fine particles contain 0.5 to 20% by mass of a dispersant, the foam volume ratio is less than 10 vol%, and the average particle diameter obtained by a dynamic light scattering method is less than 300 nm.
The pH of the aqueous polytetrafluoroethylene dispersion is preferably from 8 to 13.
In addition, the polytetrafluoroethylene aqueous dispersion preferably has a cake ratio of 40% or less obtained by standing at 25 ° C for 3 months, and a redispersion ratio at this time of 95% or more.
The feature of the polytetrafluoroethylene-containing aqueous composition of the present invention is that it contains at least a binder resin with a solid content ratio of 20 to 95% by mass and a polytetrafluoroethylene-based solid content ratio of 5 to 80. The above-constituted polytetrafluoroethylene aqueous dispersion.
The liquid coating tool of the present invention is characterized by being filled with a polytetrafluoroethylene-containing aqueous composition having the above-mentioned structure.

[Inventive effect]

According to the present invention, it provides excellent long-term dispersion stability. Even if it is added to liquid materials such as coatings, the PTFE does not separate in the final product. It can realize the function of PTFE in the desired final form and has excellent economic productivity. A polytetrafluoroethylene aqueous dispersion, an aqueous composition for imparting a polytetrafluoroethylene function, and a liquid coating tool are used.

Hereinafter, embodiments of the present invention will be described in detail.
The polytetrafluoroethylene aqueous dispersion of the present invention is characterized by containing 10 to 70% by mass of polytetrafluoroethylene fine particles having a primary particle diameter of 0.03 to 0.3 μm and a number average molecular weight Mn of 10,000 to 30,000. The fluoroethylene fine particles contain 0.5 to 20% by mass of a dispersant, the foam volume ratio is less than 10 vol%, and the average particle diameter obtained by a dynamic light scattering method is less than 300 nm.

＜ PTFE fine particles ＞
In the present invention, the PTFE fine particles are those having a primary particle diameter of 0.03 to 0.3 μm and a number average molecular weight Mn of 10,000 to 30,000.
In the present invention, the "primary particle diameter" refers to the primary particle diameter observed by SEM, and the "number average molecular weight Mn" refers to the number average molecular weight by DSC method.
The PTFE particles having the primary particle size and the number average molecular weight are obtained by an emulsion polymerization method, for example, using a method described in a fluororesin manual (edited by Takagawa Sato, Nikkan Kogyo Shimbun), etc. Number average molecular weight of PTFE particles. In addition, PTFE particles having a high number average molecular weight Mn may be irradiated with radiation such as γ rays so that the number average molecular weight Mn becomes 10,000 to 30,000 and satisfies the above-mentioned primary particle size range.
In the present invention (including examples to be described later), the so-called primary particle diameter observed with a SEM (Scanning Electron Microscope) represents the distance in the long-side direction of the PTFE fine particles having the smallest constituent unit. This SEM observation was measured using S-4700 manufactured by Hitachi High-Technologies Corporation.

In addition, the number average molecular weight Mn by DSC method (differential scanning calorimetry) was increased from a temperature increase rate of 10 ° C / min to 350 ° C, and the heat of crystallization when cooled at 10 ° C / min was calculated using the following formula: Calculate.
Mn = 2.1 × 10 ¹⁰ × ΔHc ^-5.16
Mn: number average molecular weight ΔHc: DSC crystallization heat (cal / g)
In the present invention (including examples described later), the DSC method is measured using a Thermo plus EVO2 DSC8231 manufactured by RIGAKU.

If the primary particle diameter of the PTFE particles is less than 0.03 μm, it is very difficult to ensure dispersion stability and become a dispersion that is easy to aggregate and settle. On the other hand, if it exceeds 0.3 μm, it is difficult to maintain a dispersed state without settling for a long time.
In addition, if the number average molecular weight Mn is less than 10,000, it is uneconomical because the cost of radiating radiation such as gamma rays is not economical. On the other hand, when it exceeds 30,000, PTFE fine particles are fibrillated due to shearing during dispersion. Therefore, it has become the cause of the formation of aggregates.

The content of PTFE fine particles having these characteristics varies depending on the application of the PTFE aqueous dispersion, etc., but it is desirable that it is 10 to 70% by mass based on the total amount of the PTFE aqueous dispersion (hereinafter, "mass%" is referred to as "%" ), Preferably 25 to 65%.
When the content of the PTFE fine particles is less than 10%, it is uneconomical due to an increase in manufacturing costs such as dispersion treatment. On the other hand, when it exceeds 70%, the viscosity becomes too high and the production is difficult. Poor.

The aqueous PTFE dispersion of the present invention contains a dispersant from the viewpoint of improving dispersibility and redispersibility, and of improving the wettability of PTFE with water.
The usable dispersant is not particularly limited as long as it can uniformly and stably disperse the PTFE fine particles, and various dispersants can be used.
The dispersant used is preferably a nonionic based on the viewpoint of suppressing adverse effects such as aggregation due to interaction with other materials when the final product is produced.
Examples of preferred dispersants include acrylic copolymers, fluorine copolymers, polyester copolymers, acetylene copolymers, and silicone copolymers. As a commercial product, disperbyk-184 manufactured by BYK can be used. , 185, 190, 191, 192, 193, 194, 198, 199, 2010, 2012, 2013, 2015, 2055, 2060, 2061, 2096, or Dispex UltraFA4425, 4431, 4437, 4480, 4600 made by BASF , 4601, PA4550, 4560, PX4575, 4585, BR3, A122, 123K, P30, P90, P90, Megafac F-251, 253, 281, 430, 477, 551, 552, 553, 554, COD 555, 556, 557, 558, 559, 560, 561, 562, 563, 565, 568, 569, 570, 572, 574, 575, 576, R-40, R-40-LM, R-41, R- 94, RS-56, RS-72-K, RS-75, RS-76-E, RS-76-NS, RS-78, RS-90, DS-21, Ftergent 251, 208M, 212M by NEOS , 215M, 250, 209F, 222F, 245F, 208G, 218GL, 240G, 212P, 220P, 228P, FTX-218, DFX-18, 710FL, 710FM, 710FS, 730FL, 730LM, 610FM, 683, 601AD, 601ADH2, 602A , 650AC, 681, AGC Semiche Surfon S-242, 243, 420, 386, 611, 651 made by Mical, Mowital B16H, B20H, B30T, B30H, B30HH, B45M, B45H, B60T, B60H, B60HH, B75H, BX860, Pioloform BL16, manufactured by KURARAY S-LEC BL-1, BL-1H, BL-2, BL-2H, BL-5, BL-10, BL-S, BX-L, BM-1, BM-2, BM- 5.BM-S, BH-3, BH-6, BX-1, BX-5, KS-1, KS-3, KS-5, KS-10, BUTVAR B-72, B-74 made by Solutia , B-76, B-79, B-90, B-98, Olfine D-10A, 10PG, E1004, E1010, E1020, E1030W, PD-001, 002W, 004, 005, EXP made by Nissin Chemical Industry Co., Ltd. .4001, 4002, 4123, 4300, WE-001, WE-002, WE-003, TEGO Dispers 740W, 741W, 750W, 755W, 757W, 760W, 761W, 765W, Esleam AD manufactured by Nippon Oil Company -3172M, 374M, 508E, 221P, 221J, DP-2, DJ-2, Malialim AKM-0531, AFB-1521, AAB-0851, SC-0505K, SC-1015F, SC-0708A, etc.

The content of these dispersants is preferably 0.5 to 20% relative to the PTFE fine particles, and it is desirable to be 1 to 10%.
When the content of the dispersant is less than 0.5%, dispersibility and redispersibility cannot be improved. On the other hand, when the content of the dispersant exceeds 20%, the viscosity of the dispersion becomes high, which is disadvantageous in terms of production and use. In addition, the final product produced by blending the PTFE dispersion has a form containing a lot of unnecessary components, which is not satisfactory.

From the viewpoint of storage stability and the like, the aqueous PTFE dispersion of the present invention preferably has a pH of 8 to 13, and more preferably 8.5 to 11.5.
When the pH is less than 8, the PTFE aqueous dispersion is prone to mold, which causes the multiplication of bacteria and spoils, which results in additional costs such as preservation in the refrigerator. Although it can also be adjusted to an acidic area where mold or miscellaneous bacteria do not multiply, since most industrial equipment uses stainless steel in the wetted part, it is necessary to line the wetted part, etc., resulting in additional costs. On the other hand, when the pH exceeds 13, the danger to the living body becomes large, which limits the use of the final product made by blending the PTFE dispersion.
The pH of the PTFE aqueous dispersion is adjusted according to the components used, its content, and the like, and adjusted using a pH adjuster as necessary.

Examples of usable pH adjusting agents include those containing metal ions, such as amines and sodium hydroxide. Examples of the amines include primary amines such as monoethanolamine and aminomethylpropanol, secondary amines such as diethanolamine, dimethylamine, diethylamine, diisopropylamine, and dicyclohexylamine, and triethanolamine and triamine. Tertiary amines such as propanolamine, triethylamine, tripropylamine, tributylamine, tripentylamine, pyridine, N-methylmorpholine, tetramethyl, tetraethyl, tetrapropyl, tetrabutyl, tetrabutyl At least one of pentyl, tetrahexyl, benzyltrimethyl, and individual quaternary ammonium hydroxide.
The content of these pH adjusting agents may be a content in which the pH of the PTFE aqueous dispersion is within the above-mentioned preferable range, and may contain a preferable amount.

In the PTFE aqueous dispersion of the present invention, water (ion-exchanged water, distilled water, purified water, pure water, ultrapure water, tap water, etc.) is used as a dispersion medium. However, based on further improvement of storage stability, a water-soluble solvent is preferred. Or, it may further contain an appropriate amount of at least one selected from the group consisting of a preservative, a mildew-proof agent, and a fungicide, as necessary.

The PTFE aqueous dispersion system of the present invention is added with additives such as PTFE fine particles, dispersants, etc., and dispersed and mixed using a disperser, kneader, etc. to prepare a foam volume ratio of less than 10 vol%. The average obtained by dynamic light scattering method The particle size does not reach 300 nm.
In the present invention, "foam volume" refers to the volume of foam under vacuum at a liquid temperature of 20 ° C and an absolute pressure of 0.003 MPa. The foam volume ratio of the PTFE aqueous dispersion must be less than 10 vol% relative to the volume of the PTFE aqueous dispersion. It is preferable to be 5 vol% or less. When the foam volume ratio is 10 vol% or more, the remaining air bubbles in the dispersion will hinder the dispersion of the PTFE fine particles and cause the coagulation of the PTFE fine particles. In processing using a dispersing machine, a kneading machine, etc., the air bubbles expand during heating and cause the inside of the device to expand. The pressure rises, but not so well. At least through the steps of dispersing the PTFE particles from the previous stage to filling the container with a disperser or kneader, the foam volume ratio must be kept below 10 vol%, which is better than the storage state after filling into the container. The foam volume ratio is still Keep it low. The foam volume ratio in the storage state is preferably less than 3 vol%.
In the present invention (including examples described later), the calculation of the foam volume ratio can be obtained as follows.
The volume of the aqueous PTFE dispersion at 1 atm was set to Vn, and the volume of the aqueous dispersion and the expanded bubbles when the absolute pressure of the aqueous PTFE dispersion at a liquid temperature of 20 ° C was reduced to 0.003 MPa in a vacuum container was set to Vv At this time, the bubble volume Vb can be obtained from Vb = Vv-Vn. In the present invention, the foam volume Vb at a liquid temperature of 20 ° C and an absolute pressure of 0.003 MPa relative to the volume of the polytetrafluoroethylene aqueous dispersion is less than 10 vol% [0.1> (Vv-Vn) / Vn].

In the present invention, the form in which the foam volume ratio of the PTFE aqueous dispersion does not reach 10 vol% can be performed by, for example, a vacuum defoaming treatment, a heat aging treatment, and the like.
As the vacuum defoaming treatment, a vacuum defoaming device such as a vacuum defoaming mixer can be used. For example, the PTFE aqueous dispersion is filled in the vacuum chamber, and the pressure is reduced to 0.020 MPa under absolute pressure while stirring. The other processes can be set as the foam volume ratio of the purpose.
In addition, as the heat aging treatment, the PTFE aqueous dispersion can be hermetically filled in a tank or the like, and can be left in a thermal insulation warehouse at 40-50 ° C for several days to remove bubbles, thereby reducing the foam volume ratio.
The above-mentioned foam volume ratio can be prepared by each of these processes. These defoaming treatments can be preferably performed at a more advanced stage using a dispersing machine, a kneading machine, and the like.

In addition, the average particle diameter of the PTFE particles in the PTFE aqueous dispersion of the present invention obtained by a dynamic light scattering method is less than 300 nm, and preferably 50 to 250 nm. When the average particle diameter is 300 nm or more, it is difficult to suppress sedimentation over time, and it is difficult to re-disperse, which is not preferable.
In the present invention (including examples to be described later), the measurement of the average particle diameter obtained by the dynamic light scattering method is a value measured using FPAR-1000 manufactured by Otsuka Electronics Corporation.
In the present invention, in order to make the average particle diameter obtained by the dynamic light scattering method less than 300 nm, for example, a dispersant and PTFE fine particles can be prepared in purified water, and a disperser (DYNO-MILL MULTI-LAB type manufactured by WAB Corporation, ϕ0 .3mm zirconia beads, with a filling rate of 65% and a peripheral speed of 10m / s), are continuously processed to a desired average particle diameter, and can be adjusted to the above average particle diameter.

From the viewpoint of further exerting the effects of the present invention, it is desirable that the cake ratio obtained by allowing the PTFE aqueous dispersion of the present invention to stand at 25 ° C for 3 months is 40% or less, and the redispersion ratio at this time is 95% or more.
In the present invention (including examples described later), the cake ratio obtained after standing at 25 ° C for 3 months refers to a cake filled with an aqueous PTFE dispersion in a cylindrical glass container and standing at 25 ° C for 3 months. The ratio of the block height Hc to the liquid height Hl. Hc is a value that is calculated by formulating: Hc / Hl × 100 (%) after slowly tilting the container and removing the liquid portion other than the cake.
In the present invention (including examples described later), the redispersion ratio refers to the redispersibility after standing at 25 ° C for 3 months, and after standing at 25 ° C for 3 months, a contact mixer manufactured by Yamato Scientific Co., Ltd. MT-31 is pressed vertically for 10 seconds and vibrates, and it is reversed once. After repeating this three times, the liquid portion was taken from the top without taking a cake, and the solid content was measured (180 ° C, mass after 10 minutes / mass of the liquid portion taken), and the relative initial stage of the obtained solid content was calculated as a percentage. The value obtained by the ratio of the solid content [(180 ° C, mass after 10 minutes) / (aqueous dispersion mass)]] was taken as the redispersion ratio.
In order to set the cake ratio to 40% or less, and to set the redispersion ratio to 95% or more, the primary particle size of the cake containing 10 to 70% is 0.03 to 0.3 μm and the number average molecular weight Mn is 10,000 to 30,000 PTFE fine particles, relative to the PTFE fine particles containing 0.5 to 20% of the dispersant of the PTFE aqueous dispersion intermediate, the above-mentioned defoaming treatment, using a disperser (DYB-MILL MULTI-LAB type manufactured by WAB company, ϕ0. 3mm zirconia beads with a filling rate of 65% and a peripheral speed of 10m / s) are continuously processed until the desired dispersion state is obtained, and the above-mentioned cake ratio and the above-dispersed ratio PTFE aqueous dispersion can be obtained.

The PTFE aqueous dispersion system of the present invention thus constituted contains 10 to 70% of polytetrafluoroethylene fine particles having a primary particle diameter of 0.03 to 0.3 μm and a number average molecular weight Mn of 10,000 to 30,000. The microparticles contain 0.5 to 20% of dispersant, the foam volume ratio is less than 10vol%, and the average particle size obtained by dynamic light scattering method is less than 300nm, which can obtain excellent long-term dispersion stability, even if added to liquid materials such as coatings. The PTFE does not separate in the final product, and it can realize the function of PTFE in the desired final form, and it is an economical and excellent productivity Teflon aqueous dispersion.
The PTFE aqueous dispersion of the present invention does not separate the PTFE inside the final product, and can realize the function of PTFE in the desired final form, so it can be better used as ink, coating (varnish, paint, etc.), grease 、 Toners for modifiers, as smoothing or abrasion resistance improvers for engineering materials such as polyimide, polyimide, polycarbonate, polyphenylene sulfide, etc. Additives for plating solutions, etc. In addition, as an additive for molding materials, it can be suitably used in applications such as improving the non-adhesiveness and sliding characteristics of rollers of photocopiers, mounting products such as dashboards of automobiles, household appliances, and electrical equipment. The use of the texture of molded products such as covers, or the use to improve the smoothness or wear resistance of mechanical parts such as bearings, gears, cams, sliding materials and other mechanical friction, to improve oil repellency or water repellency such as wax It can be used for various purposes, such as the hardness adjuster of electrode adhesives for secondary batteries such as lithium batteries or fuel cells, and the water repellent treatment agent for electrode surfaces.

The feature of the polytetrafluoroethylene-containing aqueous composition of the present invention is that it contains at least a binder resin with a solid content ratio of 20 to 95% and a polytetrafluoroethylene-based solid content ratio of 5 to 80%. A polytetrafluoroethylene aqueous dispersion having the above structure.
As a binder resin that can be used, a suitable binder can be selected according to the application of ink, paint (varnish, paint, etc.), grease, toner, lithium battery, secondary battery, or fuel cell electrode binder, etc. Examples of the agent resin include at least one kind of water dispersion such as ethylene resin, thermoplastic resin, curable resin, thermoplastic block copolymer, and elastomer.
Examples of the ethylene resin include aqueous dispersions of vinyl acetate resin, acrylic resin, and styrene resin. Examples of the thermoplastic resin include an aqueous dispersion of a polyolefin resin, an ethylene-vinyl acetate copolymer, and a polyamide resin. Examples of the curable resin include aqueous dispersions of epoxy resins, urethane resins, polyimide resins, and unsaturated polyester resins. The curable resin may be a room temperature curable resin, a thermosetting resin, or a photocurable resin. Examples of the thermoplastic block copolymer include a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, and a styrene-butadiene-styrene block copolymer. Hydrogenated products of block copolymers, and hydrogenated products of styrene-isoprene-styrene block copolymers. Examples of the elastomer include aqueous dispersions of styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

It is desirable that the polytetrafluoroethylene aqueous dispersion used contains 10 to 70% of the above-mentioned polytetrafluoroethylene fine particles having a primary particle diameter of 0.03 to 0.3 μm and a number average molecular weight Mn of 10,000 to 30,000. Fluorinated ethylene microparticles contain 0.5 ~ 20% dispersant, foam volume ratio is less than 10vol%, and aqueous dispersion of polytetrafluoroethylene with average particle size of less than 300nm obtained by dynamic light scattering method, preferably pH 8 ~ 13 And / or the cake ratio obtained after standing at 25 ° C for 3 months is less than 40%, and the redispersion ratio at this time is more than 95%.

The aqueous composition for imparting a polytetrafluoroethylene function according to the present invention may contain an appropriate amount of, for example, a coloring agent, in addition to the above-mentioned binder resin and the above-mentioned polytetrafluoroethylene aqueous dispersion, as long as the effect of the present invention is not impaired. , Antioxidants, heat stabilizers, light stabilizers, UV absorbers, slip agents, antistatic agents and other additives.
The content of the above-mentioned adhesive resin is expected to be 20 to 95% based on the solid content ratio based on the total solid content in the aqueous composition that imparts the function of PTFE based on the viewpoints of film-forming properties and fixation properties. It is preferably 30 to 90%.
In addition, the content of the PTFE aqueous dispersion having the above-mentioned configuration is based on the viewpoint of the PTFE function development and the viewpoint of the fixing property, etc., and it is desired that the content of the PTFE function is 5 to 80% based on the solid content ratio based on the total amount of the water-based composition that imparts the PTFE function. , Preferably 10 to 60%.

The polytetrafluoroethylene-containing water-containing composition of the present invention thus constituted is also excellent in dispersion stability for the binder resin, and does not separate PTFE inside the final product such as ink, paint (varnish, paint, etc.). In the desired final form of each application, the water repellency, oil repellency, electrical properties, heat resistance, electrical insulation, low dielectric properties, low friction properties, non-adhesion properties, weather resistance, and difficulty of PTFE can be achieved according to the purpose. It is a water-based composition that imparts various functions such as flammability, and has an economical and excellent productivity that imparts a polytetrafluoroethylene function.

The liquid coating tool of the present invention is characterized by being filled with a polytetrafluoroethylene-containing aqueous composition having the above-mentioned structure.
As a liquid coating tool that can be used 1) If it is an aqueous composition that can be filled with the polytetrafluoroethylene function provided in the above configuration, the coating part (coated body) provided in the front will provide the polytetrafluoroethylene function The application of the aqueous composition to an object is not particularly limited, and for example, a shaft cylinder having at least a water-based composition for imparting a function of imparting polytetrafluoroethylene, and a coating portion provided as a coating member at the front end of the shaft cylinder are provided. And a liquid mechanism having a structure provided between the shaft cylinder and the coating section, and applying the structure containing the polytetrafluoroethylene function in the shaft cylinder to the coating section by pressing the coating section. Cloth tool, or 2) a specific coating part is provided at the front end, and a polytetrafluoroethylene function-containing water-containing composition filled inside the body part that becomes the shaft cylinder is pressed forward by a liquid pressing mechanism installed on the body part For the liquid coating tool supplied to the coating section, 3) a specific coating section is provided at the front end, and an aqueous composition that imparts a polytetrafluoroethylene function to the inside of the body portion that becomes the shaft cylinder is provided. Coating section and shaft Liquid applicator member like a relay between the supply of a capillary force of the coated portion.
The liquid coating tool of the present invention is filled with a polytetrafluoroethylene function-imparting aqueous composition having the above-mentioned structure, so that it can easily and uniformly apply uniformly to a polymerized object without blurring or deviation. Tetrafluoroethylene functional water-based composition.

[Example]

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. The present invention is not limited to the following examples and the like.

[Examples 1 to 3 and Comparative Examples 1 to 7: Preparation of PTFE aqueous dispersion]
Use the disperser: DYNO-MILL MULTI-LAB based on the formulations (PTFE particles, dispersant, pH modifier, and water) shown in Table 1 below. Dispersion conditions: zirconia beads: 0.01mm, filling rate: 50% At a circumferential speed of 10 m / s, after performing batch processing for 1 hour, the beads were separated and the aqueous PTFE dispersion was recovered.
Next, in the vacuum defoaming process ("Yes" in Table 1), a vacuum defoaming device (manufactured by MIXTER Industries, a small vacuum defoaming mixer) was used to fill the vacuum chamber with the examples and comparative examples. Each PTFE aqueous dispersion was reduced to an absolute pressure of 0.020 MPa while stirring, and then returned to atmospheric pressure for processing after 10 minutes.

About each obtained PTFE aqueous dispersion, the foam volume ratio and average particle diameter were measured by the said measuring method, and pH was measured by the following method.

(pH measurement method)
About each obtained PTFE aqueous dispersion (25 degreeC), it measured using the pH meter (made by HORIBA company, F-72).
Moreover, about each obtained PTFE aqueous dispersion, the cake ratio (%) and redispersion ratio after standing at 25 degreeC for 3 months were measured by the said method.
The measurement and evaluation results are shown in Table 1 below.

(Evaluation of water-based composition imparting PTFE function)
Further, each of the obtained PTFE aqueous dispersions of Examples 1 to 3 and Comparative Examples 1 to 7 had a solid content basis of 50% by mass, and an adhesive resin 1 (acrylic resin, Neocryl XK-190, manufactured by Kusumoto Chemical Co., Ltd., having a solid content of 45 Mass%) or adhesive resin 2 (urethane resin, SUPERFLEX 150, manufactured by Daiichi Kogyo Co., Ltd., solid content of 30% by mass) is mixed in a beaker with a solid content of 50% by mass, stirred by hand, and prepared for implementation Examples 1 to 3 and Comparative Examples 1 to 7 correspond to the aqueous compositions 1 and 2 each having a PTFE function.
The obtained PTFE-functional aqueous compositions 1 and 2 were evaluated for dispersion stability by the following evaluation methods. The evaluation results are shown in Table 1 below.

(Evaluation of dispersion stability)
For each of the obtained aqueous compositions that imparted a PTFE function, the functional evaluation was performed visually based on the following evaluation criteria for the dispersibility at 40 ° C after one week.
Evaluation benchmark:
A: Good
B: Slight aggregation and sedimentation
C: There is complete agglutination or sedimentation

(Coatability Evaluation of Liquid Coating Tools)
Fill a container of liquid coating tool (PC-17K, coating part: felt fiber coating body, shaft material: PP resin, size: shaft diameter × 28.0 × length 157.00mm) made by Mitsubishi Pencil Co., Ltd. with PTFE A functional aqueous composition 1 was coated on an acrylic resin plate (100 × 100 × 5 mm), and the applicability was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 1 below.

Evaluation benchmark:
A: Good
B: Slight blur and deviation
C: Completely blurred and deviated

As can be understood from the results in Table 1 above, it is confirmed that Examples 1 to 3 of the present invention and Comparative Examples 1 to 7 outside the scope of the present invention have excellent long-term dispersion stability, even when added to liquid materials such as paints. The PTFE in the final product is not separated, and it can achieve the function of PTFE in the desired final form. It has an economical and excellent productivity PTFE aqueous dispersion.
In addition, it was confirmed that the liquid coating tool filled with the PTFE-functional aqueous composition of the PTFE aqueous dispersions of Examples 1 to 3 described above was excellent in dispersion stability and coating properties.

[Industrial availability]

The aqueous PTFE dispersion of the present invention has excellent long-term dispersion stability, and even if it is added to a liquid material such as a coating material, the PTFE does not separate in the final product. It can realize the function of PTFE in the desired final form, which is economical. It is also excellent in productivity, so it can be used as a modifier for modifying inks, coatings (varnishes, paints, etc.), grease, and toner, as polyimide, polyimide, polycarbonate, Polyphenylene sulfide and other engineering plastics, etc. are used to improve the smoothness or abrasion resistance of forming materials, as additives to plating solutions.

Claims (5)

A polytetrafluoroethylene aqueous dispersion, which is characterized by containing 10 to 70% by mass of polytetrafluoroethylene fine particles having a primary particle diameter of 0.03 to 0.3 μm and a number average molecular weight Mn of 10,000 to 30,000. The ethylene fine particles contain 0.5-20% by mass of a dispersant, the foam volume ratio is less than 10 vol%, and the average particle diameter obtained by a dynamic light scattering method is less than 300 nm. The aqueous polytetrafluoroethylene dispersion according to claim 1, wherein the pH is 8 to 13. For example, the polytetrafluoroethylene aqueous dispersion of claim 1 or 2, wherein the cake ratio obtained after standing at 25 ° C for 3 months is 40% or less, and the redispersion ratio at this time is 95% or more. An aqueous composition imparting a function of polytetrafluoroethylene, characterized in that it contains at least a binder resin in a solid content ratio of 20 to 95% by mass, and a solid content ratio in a polytetrafluoroethylene standard of 5 to 80 mass % Of a polytetrafluoroethylene aqueous dispersion as claimed in any one of claims 1 to 3. A liquid coating tool filled with a polytetrafluoroethylene-containing aqueous composition as claimed in claim 4.