KR102387084B1 - Polytetrafluoroethylene dispersion in oily solvent - Google Patents

Abstract

To provide an oil-based solvent dispersion of polytetrafluoroethylene (PTFE) suitable for addition of resist materials and epoxy resin materials, etc., which have low viscosity and excellent storage stability due to fine particle diameter. As this PTFE oil-based solvent dispersion, 5 to 70 mass % of polytetrafluoroethylene micropowder having a primary particle diameter of 1 μm or less, and a fluorine-based additive containing at least a fluorine-containing group and a lipophilic group is added to the polytetrafluoroethylene micropowder. 0.1-40 mass % with respect to mass, and the oil-based solvent type dispersion which makes the total moisture content by the Karl-Fischer method 20000 ppm or less is mentioned.

Description

Polytetrafluoroethylene oil-based solvent dispersion {POLYTETRAFLOOROETHYLENE DISPERSION IN OILY SOLVENT}

The present invention relates to an oil-based solvent dispersion of polytetrafluoroethylene suitable for adding a resist material, adding an epoxy resin material, etc., having a low viscosity and excellent storage stability in terms of particle diameter.

In recent years, with the progress of high-speed and high-functionality of electronic devices, high-speed communication speed and the like are required. Among these, low dielectric constant and low dielectric loss tangent of various electronic device materials are required, and resist materials including black matrix materials for liquid crystal displays, insulating materials, and substrate materials are also required to have low dielectric constant and low dielectric loss tangent.

Polytetrafluoroethylene (PTFE), which has the most excellent properties among resin materials, is attracting attention as a material with low dielectric constant and low dielectric loss tangent. It is possible to achieve low dielectric loss tangent.

Polytetrafluoroethylene (PTFE) is a material excellent in heat resistance, electrical insulation, low friction properties, non-tackiness, weather resistance, etc. in addition to the above-mentioned low dielectric constant and low dielectric loss tangent, and the resist material, insulating material, substrate material, etc. It is used in electronic devices, sliding materials, automobiles, kitchen appliances, and the like. Polytetrafluoroethylene having such characteristics is added to various resin materials, rubbers, adhesives, lubricants or greases, printing inks and paints, etc. as micropowders and is used for the purpose of improving product characteristics.

Such micropowder of polytetrafluoroethylene is usually obtained by polymerizing tetrafluoroethylene (TFE) monomer in the presence of a stabilizer such as water, a polymerization initiator, a fluorine-containing emulsifier, or paraffin wax by an emulsion polymerization method to obtain polytetrafluoroethylene. After obtaining as an aqueous dispersion containing rethylene microparticles|fine-particles, it is manufactured through concentration, aggregation, drying, etc. (for example, refer patent document 1).

As a method of adding this micropowder of polytetrafluoroethylene to a resin material, for example, in addition to direct mixing, a method of dispersing in water or an oil-based solvent and mixing as a PTFE dispersion is known. Once dispersed in water or an oil-based solvent, it can be mixed uniformly by adding it.

However, polytetrafluoroethylene micropowder has a strong cohesive force between particles, and it is difficult to disperse the polytetrafluoroethylene micropowder in a form that has a low viscosity and excellent storage stability especially in an oil-based solvent with a fine particle diameter.

In addition, when adding to a water-insoluble resin or resist material, an oil-based solvent-based polytetrafluoroethylene dispersion is required, and many inventions related to an aqueous dispersion of polytetrafluoroethylene are known (for example, , see Patent Documents 2 and 3), and compared with this aqueous dispersion, there are currently few reports of polytetrafluoroethylene dispersions in oil-based solvent systems (see, for example, Patent Documents 4 and 5) ).

The technique described in Patent Document 4 consists of PTFE particles and at least one mono- or polyolefin-based unsaturated oil or oil mixture, and the molecules of the olefin-based unsaturated oil are on the surface of the PTFE (primary) particles, in a radical reaction. long-term stable oil-PTFE that is covalently/chemically bonded by Dispersion, the preparation method is that a modified PTFE (emulsion) polymer having a persistent perfluoro (peroxy) radical is mixed with at least one olefinically unsaturated oil, and then a modified PTFE (emulsion) polymer is It is obtained by a method applied to mechanical stress, etc., the manufacturing method is complicated, and does not use general-purpose PTFE particles, and the technical idea (configuration and its effect) is completely different from this invention.

In addition, the technique described in Patent Document 5 is "a fluoropolymer such as PTFE, a non-aqueous medium such as an organic solvent having a boiling point of 40 to 250° C., and a dispersion stabilizer with the general formula: Rf1-(X)nY [wherein, Rf1 is a partially fluorinated or fully fluorinated alkyl group having 1 to 12 carbon atoms, n is 0 or 1, X is -O-, -COO- or -OCO-, Y is -(CH ₂ )pH, - (CH ₂ )pOH or -(OR1)q(OR2)rOH, p is an integer from 1 to 12, q is an integer from 1 to 12, r is an integer from 0 to 12, R1 and R2 are 2 to It is an alkylene group having 4 carbon atoms. However, it is different from R1 and R2.] A fluoropolymer non-aqueous dispersion characterized in that it contains at least one selected from the fluorine compounds represented by , and a moisture content of 1% or less.” and the like.

However, in Patent Document 5, there is no description or suggestion regarding "polytetrafluoroethylene micropowder having a primary particle diameter of 1 µm or less”. In paragraph [0041] of this Patent Document 5, there is a description to the effect that “in the case of dispersing a powdery fluoropolymer, it is possible to obtain a dispersion which is difficult to re-agglomerate by dispersing it in a size of 5 to 500 μm.” Experimental examples serving as examples For supports 1 to 12, "Lubron L-2 (PTFE)" manufactured by Daikin Industries, Ltd. as a "fluoropolymer" (in the technical data, average particle diameter (50%) 3.5 µm by dry laser method) is used. In addition, it is described as “a size of 0.05 to 5 μm when the aqueous dispersion is phase-inverted”. As described above, in Patent Document 5, when polytetrafluoroethylene micropowder powder is used, it is not assumed to use particles of 1 μm or less, or when the powder is implicitly dispersed, it is difficult.

In addition, regarding the moisture content, in Patent Document 5, in paragraph [0048], the moisture content is 0.1% or less, preferably 0.1% or less, preferably 0.01% or less. It is described that control of the moisture content becomes important when mixed with and used. On the other hand, in the present invention, the moisture content is controlled for stability of the dispersion system after dispersion preparation, not at the time of mixing, and does not refer to the case of mixing in Patent Document 5. Furthermore, in Document 5, the effect of the moisture content is It is not demonstrated by Examples etc.

Therefore, although the said patent document 5 discloses the proximity technique of this invention, the said patent document 5 and this invention differ in the technical idea (a structure and its operation effect).

In addition, conventionally, as a method of mixing a powder material such as PTFE micropowder into a resist material, for example, as a method of adjusting a resist material for a black matrix, a coloring paste containing a pigment as a main component is prepared, followed by a photosensitive resin composition and Although methods such as mixing are known (see, for example, Patent Documents 6 and 7), similarly to these methods, micropowders of PTFE are dispersed in an oil-based solvent system and then mixed in a resist material, etc. have been attempted. .

However, PTFE micropowders such as those in Patent Documents 6 and 7 have a strong cohesive force between the particles, and there is a problem that it is difficult to disperse and mix them uniformly in a resin material such as a resist material with a fine particle diameter.

In particular, the resist material is a material that forms a fine pattern by exposure and development. If the PTFE particle diameter is large or not uniformly dispersed, it is undesirable, such as causing defects during pattern formation, and high A dispersion of PTFE having acidity is required.

Moreover, although an epoxy resin material exists as one of the materials widely used as a board|substrate or sealing material of an electronic device, Although the dielectric constant of an epoxy resin material changes with the composition, it shows about 2.5-6.

On the other hand, as a material of low dielectric constant and low dielectric loss tangent, polytetrafluoroethylene (PTFE, relative dielectric constant 2.1), which has the most excellent properties among resin materials, is attracting attention as described above, but PTFE is melt-mixed among various resin materials. is being used, etc. (For example, refer to Patent Document 8)

Melt mixing as in Patent Document 8 is not suitable for mixing with a thermosetting resin material, a reactive resin material, a resin material having lower heat resistance than PTFE, etc. Even if it is a method of adding in order to lower the dielectric constant or dielectric loss tangent of an epoxy resin material, it is not suitable.

Among these, a method, a material, etc. in which PTFE is uniformly mixed at a high concentration among epoxy resin materials widely used in electronic materials are required.

Japanese Patent Laid-Open No. 2012-92323 Japanese Patent Laid-Open No. 2006-169448 Japanese Patent Laid-Open No. 2009-179802 Japanese Patent Publication No. 2011-509321 Japanese Patent Laid-Open No. 2011-225710 Japanese Patent Application Laid-Open No. 6-289216 Japanese Patent Laid-Open No. 2008-242377 Japanese Patent Laid-Open No. 2001-49068

The present invention is intended to solve the above-mentioned problems and developments in the prior art, and it is a polytetrafluoroethylene oil-based solvent suitable for addition of resist materials, addition of epoxy resins, etc., which is excellent in storage stability and low viscosity with fine particle diameter. It aims to provide a dispersion.

As a result of intensive studies on the above-mentioned conventional problems, the present inventors found that, by the following first to sixth inventions, an oil-based solvent-based dispersion of polytetrafluoroethylene for the above object was obtained, and completed the present invention. had reached

That is, according to the first invention, 5 to 70% by mass of polytetrafluoroethylene micropowder having a primary particle diameter of 1 μm or less, and a fluorine-based additive containing at least a fluorine-containing group and a lipophilic group is 0.1 to the mass of polytetrafluoroethylene. It is an oil-based solvent-based dispersion of polytetrafluoroethylene, characterized in that the total moisture content by the Karl-Fischer method is 20000 ppm or less, including -40 mass %.

The second invention is an oil-based solvent dispersion of polytetrafluoroethylene according to the first invention, characterized in that the water content of the oil-based solvent used in the oil-based solvent dispersion according to the Karl-Fischer method is 20000 ppm or less.

According to the third invention, the oil-based solvent used in the oil-based solvent dispersion is γ-butyrolactone, acetone, methyl ethyl ketone, hexane, heptane, octane, 2-heptanone, cycloheptanone, cyclohexanone, cyclohexane. , methylcyclohexane, ethylcyclohexane, methyl-n-pentyl ketone, methyl isobutyl ketone, methyl isopentyl ketone, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, ethylene glycol monoacetate, ethylene glycol monomethyl ether Acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monoacetate, diethylene glycol diethyl ether, propylene glycol monoacetate, dipropylene glycol monoacetate, propylene glycol diacetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate , Propylene glycol monoethyl ether acetate, cyclohexyl acetate, 3-ethoxy ethyl propionate, dioxane, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethoxy Ethyl propionate, anisole, ethyl benzyl ether, crezyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butylphenyl ether, benzene, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, Cymene, mesitylene, methanol, ethanol, isopropanol, butanol, methyl monoglycidyl ether, ethyl monoglycidyl ether, butyl monoglycidyl ether, phenyl monoglycidyl ether, methyl diglycidyl ether, ethyldiol Glycidyl ether, butyl diglycidyl ether, phenyl diglycidyl ether, methylphenol monoglycidyl ether, ethylphenol monoglycidyl ether, butylphenol monoglycidyl ether, mineral spirit, 2-hydroxy Ethyl acrylate, tetrahydrofurfuryl acrylate, 4-vinylpyridine, N-methylpyrrolidone, 2-ethylhexyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate One kind of solvent selected from the group consisting of acrylate, neopentyl glycol diacrylate, hexanediol diacrylate, trimethylolpropane triacrylate, methacrylate, methyl methacrylate, styrene, or these An oil-based solvent-based dispersion of polytetrafluoroethylene according to the first or second invention of the present invention, characterized by containing two or more solvents.

According to the fourth invention, the average particle diameter of polytetrafluoroethylene micropowder by laser diffraction/scattering method or dynamic light scattering method in the oil-based solvent-based dispersion is 1 μm or less. It is an oil-based solvent-based dispersion of polytetrafluoroethylene according to the invention.

The fifth invention is an oil-based solvent-based dispersion of polytetrafluoroethylene according to the first to fourth inventions of the present invention, characterized in that it further contains a silicone-based antifoaming agent.

The sixth invention is characterized in that the oil-based solvent dispersion of polytetrafluoroethylene according to any one of the first to fifth inventions is used for adding a resist material or for adding an epoxy resin material.

The oil-based solvent dispersion of polytetrafluoroethylene of the present invention has a low viscosity with a fine particle diameter, excellent storage stability, and excellent redispersibility even after long-term storage. In addition, even when a large amount of fluorine-based additives are contained, it has excellent defoaming properties, and can be uniformly mixed even when added to various resin materials such as resist materials and epoxy resins, rubber, adhesives, lubricants, greases, printing inks, and paints.

EMBODIMENT OF THE INVENTION Below, embodiment of this invention is described in detail.

The oil-based solvent dispersion of polytetrafluoroethylene of the present invention contains 5 to 70 mass% of polytetrafluoroethylene micropowder having a primary particle diameter of 1 μm or less, and a fluorine-based additive containing at least a fluorine-containing group and a lipophilic group. It is characterized by containing 0.1-40 mass % with respect to the mass of fluoroethylene micropowder.

The polytetrafluoroethylene micropowder used in the present invention has a primary particle diameter of 1 µm or less.

Such micropowder of polytetrafluoroethylene is obtained by an emulsion polymerization method, for example, the method described in the fluororesin handbook (Kurokawa Takatomi edition, Ilgan Kogyo Shimbun), etc. can be obtained by The polytetrafluoroethylene micropowder obtained by the emulsion polymerization is agglomerated and dried, and is recovered as a fine powder as secondary particles having agglomerated primary particle diameter. can

As the primary particle diameter of polytetrafluoroethylene micropowder, the volume-based average particle diameter (50% volume diameter, median diameter) measured by laser diffraction/scattering method, dynamic light scattering method, image imaging method, etc. is 1 μm or less, It is necessary in order to disperse|distribute stably in an oil-based solvent, Preferably it is 0.5 micrometer or less, More preferably, it is 0.3 micrometer or less, and it becomes a more uniform dispersion.

If the primary particle diameter of the polytetrafluoroethylene micropowder exceeds 1 µm, it is not preferable because it tends to settle in an oil-based solvent and makes it difficult to disperse stably.

Moreover, although the lower limit of the said average particle diameter is so favorable that it is low, 0.05 micrometer or more is preferable from a manufacturability, a cost point, etc..

In addition, the primary particle diameter of polytetrafluoroethylene micropowder in the present invention represents a value obtained by laser diffraction/scattering method, dynamic light scattering method, etc. in the polymerization step of micropowder. In this case, the cohesive force between the primary particles is strong, and since it is difficult to easily measure the primary particle diameter by a laser diffraction/scattering method, a dynamic light scattering method, or the like, a value obtained by an image imaging method may be indicated. As a measuring device, for example, a dynamic light scattering method by FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.), a laser diffraction/scattering method by microtrack (manufactured by Nikkiso Corporation), or an image by MacView (manufactured by Mountec Co., Ltd.) An imaging method, etc. are mentioned.

In the present invention, 5 to 70 mass% of polytetrafluoroethylene micropowder is contained with respect to the total amount of the dispersion, and preferably 10 to 50 mass% is contained.

When the content is less than 5% by mass, the amount of the oil-based solvent is large and the viscosity is extremely lowered, so not only the microparticles of the polytetrafluoroethylene micropowder are likely to settle, but also when mixed with a material such as a resin, the oil-based solvent Defects caused by a large amount of , for example, an undesirable situation may occur, such as requiring time to remove the solvent. On the other hand, when it exceeds 70 mass %, polytetrafluoroethylene micropowder tends to aggregate, and since it becomes extremely difficult to maintain the state of microparticles|fine-particles stably and it has fluidity|liquidity, it is unpreferable.

The fluorine-based additive in the present invention is not particularly limited as long as it needs to have at least a fluorine-containing group and a lipophilic group, and at least a fluorine-containing group and a lipophilic group.

By using a fluorine-based additive having at least a fluorine-containing group and a lipophilic group, the surface tension of the oil-based solvent used as the dispersion medium is lowered, the wettability to the polytetrafluoroethylene surface is improved, and the dispersibility of the polytetrafluoroethylene micropowder is improved. At the same time, the fluorine-containing group is adsorbed to the polytetrafluoroethylene surface, the lipophilic group is extended in the oil-based solvent used as the dispersion medium, and the steric hindrance of the lipophilic group prevents aggregation of the polytetrafluoroethylene micropowder and disperses it. This will further improve stability.

Examples of the fluorine-containing group include a perfluoroalkyl group and perfluoroalkenyl group, and examples of the lipophilic group include one or two or more of an alkyl group, a phenyl group, and a siloxane group, As a hydrophilic group, 1 type, or 2 or more types, such as ethylene oxide, an amide group, a ketone group, a carboxyl group, and a sulfone group, are mentioned, for example.

As a fluorine-based additive that can be specifically used, a sulflon series (manufactured by AGC Semi-Chemical Co., Ltd.) such as sulflon S-611 containing a perfluoroalkyl group, Megapac F-555, Megapack F-558, and Megapack F-563 Megapack series (manufactured by DIC Corporation), such as Unidyne series (manufactured by Daikin Industries, Ltd.), such as Unidyne DS-403N, can be used.

These fluorine-based additives are suitably selected depending on the type of polytetrafluoroethylene micropowder and oil-based solvent to be used, but it is also possible to use one type or a combination of two or more types.

The content of the fluorine-based additive is 0.1 to 40 mass % with respect to the mass of the polytetrafluoroethylene micropowder, preferably 5 to 30 mass %, more preferably 15 to 25 mass % .

When this content is less than 0.1 mass % with respect to the mass of polytetrafluoroethylene, the surface of the micropowder of polytetrafluoroethylene cannot be sufficiently wetted with the oil-based solvent, whereas when it exceeds 40 mass %, the dispersion of the dispersion becomes strong and the foaming becomes strong. It is undesirable because it lowers the efficiency of the dispersion itself and causes defects even when handling the dispersion itself or mixing it with a resin material after that.

In the oil-based solvent dispersion of polytetrafluoroethylene in the present invention, it is also possible to use other surfactants in combination with the fluorine-based additives as described above, as long as the effects of the present invention are not impaired.

For example, although surfactants, such as nonionic type, anionic type, cationic type, and polymeric surfactant, such as nonionic type, anionic type, cationic type, etc. are mentioned, It can use without limitation to these.

It is preferable that the oil-based solvent used in the present invention has a moisture content of 20000 ppm or less [0 ≤ moisture ≤ 20000 ppm] according to the Karl-Fischer method.

In the present invention (including Examples and the like described later), the measurement of the moisture content by the Karl-Fischer method is in accordance with JIS K 0068:2001, and was implemented by MCU-610 (manufactured by Kyoto Electronics Industry Co., Ltd.).

Depending on the polarity of the oil-based solvent used, high compatibility with water is considered. However, when it has a water content of 20000 ppm or more, the dispersibility of polytetrafluoroethylene micropowder in the oil-based solvent is significantly inhibited, resulting in increase in viscosity and separation between particles. will cause agglomeration.

In the present invention, by setting the water content in the oil-based solvent to 20000 ppm or less, it is possible to obtain an oil-based solvent dispersion of polytetrafluoroethylene excellent in storage stability and low viscosity in terms of particle diameter.

Further, it is preferable that the polytetrafluoroethylene oil-based solvent dispersion of the present invention has a water content of 20000 ppm or less [0 ≤ moisture ≤ 20000 ppm] according to the Karl-Fischer method.

In addition to the amount of water contained in the oil-based solvent, water contained in the material itself, such as polytetrafluoroethylene micropowder or fluorine-based additive, or water may be mixed in the manufacturing process of dispersing polytetrafluoroethylene micropowder in an oil-based solvent. , finally, by setting the water content of the polytetrafluoroethylene oil-based solvent dispersion to 20000 ppm or less, it is possible to obtain a polytetrafluoroethylene oil-based solvent dispersion excellent in storage stability.

In order to set the water content of an oil-based solvent to 20000 ppm, although it is possible to use the dehydration method of the oil-based solvent generally used, for example, a molecular sieve etc. can be used. In addition, polytetrafluoroethylene can be used in a state in which the water content has been sufficiently reduced by performing dehydration by heating, reduced pressure, or the like.

In addition, after preparing the oil-based solvent dispersion of polytetrafluoroethylene, it is also possible to remove moisture using a molecular sieve or membrane separation method, etc. As long as it can be used, it can be used without any particular limitation.

Examples of the oily solvent used in the present invention include γ-butyrolactone, acetone, methyl ethyl ketone, hexane, heptane, octane, 2-heptanone, cycloheptanone, cyclohexanone, cyclohexane, methylcyclohexane, Ethylcyclohexane, methyl-n-pentyl ketone, methyl isobutyl ketone, methyl isopentyl ketone, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, ethylene glycol monoacetate, ethylene glycol monomethyl ether acetate, ethylene glycol mono Ethyl ether acetate, diethylene glycol monoacetate, diethylene glycol diethyl ether, propylene glycol monoacetate, dipropylene glycol monoacetate, propylene glycol diacetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl Ether acetate, cyclohexyl acetate, ethyl 3-ethoxypropionate, dioxane, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, anisole , ethylbenzyl ether, crezyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butylphenyl ether, benzene, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, Methanol, ethanol, isopropanol, butanol, methyl monoglycidyl ether, ethyl monoglycidyl ether, butyl monoglycidyl ether, phenyl monoglycidyl ether, methyl diglycidyl ether, ethyl diglycidyl ether, Butyl diglycidyl ether, phenyl diglycidyl ether, methylphenol monoglycidyl ether, ethylphenol monoglycidyl ether, butylphenol monoglycidyl ether, mineral spirit, 2-hydroxyethyl acrylate, tetra Hydrofurfuryl acrylate, 4-vinylpyridine, N-methylpyrrolidone, 2-ethylhexyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate, neopentyl One solvent selected from the group consisting of glycol diacrylate, hexanediol diacrylate, trimethylolpropane triacrylate, methacrylate, methyl methacrylate, and styrene, or two or more of these solvents it is doing

Although the above-mentioned oil-based solvent is used in the present invention, it is also possible to use one or another oil-based solvent in combination with other oil-based solvents. thing is chosen

Content of the oil-based solvent to be used becomes the remainder of the said polytetrafluoroethylene micropowder and a fluorine-type additive.

In the present invention, the average particle diameter of the polytetrafluoroethylene micropowder in the oil-based solvent dispersion by laser diffraction/scattering method or dynamic light scattering method is preferably 1 µm or less.

Even when polytetrafluoroethylene micropowder having a primary particle diameter of 1 μm or less is used, the primary particles usually aggregate to form micropowders having a particle diameter of 1 μm or more as secondary particles. By dispersing the secondary particles of polytetrafluoroethylene so as to have a particle diameter of 1 μm or less, for example, by dispersing using a disperser such as an ultrasonic disperser, three rolls, ball mill, bead mill, jet mill, etc. Even when stored, a stable dispersion can be obtained.

In the present invention, the oil-based solvent-based dispersion of polytetrafluoroethylene may further contain a silicone-based antifoaming agent.

In particular, when the polytetrafluoroethylene micropowder is used at a high concentration of 70% by mass or the fluorine-based additive is used at a high concentration of 40% by mass relative to the mass of the polytetrafluoroethylene micropowder, the foaming of the dispersion may occur in the dispersion manufacturing process. , stability, lead to causing great problems in mixing with resin materials and the like.

As an antifoaming agent, there are silicone emulsion type, self-emulsifying type, oil type, oil compound type, solution type, powder type, solid type, etc., but the most suitable one is appropriately selected in combination with the oil-based solvent to be used. In particular, it is preferable to use, for example, a hydrophilic or water-soluble silicone-based antifoaming agent in order to exist at the interface between the oil-based solvent and air rather than the interface between the oil-based solvent and the polytetrafluoroethylene micropowder, but without being limited thereto, it will be available Although content of an antifoamer fluctuates with content (concentration) etc. of polytetrafluoroethylene micropowder, Preferably it is 1 mass % or less as an active ingredient with respect to dispersion whole quantity.

The oil-based solvent dispersion of polytetrafluoroethylene of the present invention constituted in this way comprises polytetrafluoroethylene micropowder having a primary particle diameter of 1 μm or less, and a fluorine-based additive containing at least a fluorine-containing group and a lipophilic group. By using a specific amount, it is excellent in low viscosity and storage stability in terms of particle diameter, and is excellent in redispersibility even after long-term storage. In addition, even when a large amount of fluorine-based additives is contained, it has excellent defoaming properties, and can be mixed uniformly even when added to various resin materials, rubber, adhesives, lubricants, greases, printing inks, paints, and the like.

Therefore, the oil-based solvent dispersion of polytetrafluoroethylene of the present invention is widely used as a substrate or sealing material for electronic devices by adding it to a photoresist such as a color filter or black matrix, or a resist material such as a screen printing resist. By adding it to the existing epoxy resin material, it is possible to achieve further lower dielectric constant and lower dielectric dissipation tangent, so that it can be suitably used for adding a resist material or for adding an epoxy resin material.

Example

EMBODIMENT OF THE INVENTION Hereinafter, this invention is further demonstrated in detail with reference to an Example and a comparative example. In addition, the present invention is not limited to the following examples.

[Examples 1 to 8 and Comparative Examples 1 to 7]

Oil-based solvent-based dispersions of polytetrafluoroethylene were prepared by each method shown below. Moreover, about the oil-based solvent to be used, the oil-based solvent used as each water content by adding a molecular sieve or water|moisture content, etc. was used. The compounding compositions of Examples 1 to 8 and Comparative Examples 1 to 7 are shown in Table 1 below.

(Example 1)

As the polytetrafluoroethylene micropowder, a powder having an average particle diameter of 0.12 µm by laser diffraction and scattering was used. As the fluorine-based additive, Megapack F-558 manufactured by DIC Corporation (a fluorine-containing and lipophilic group-containing oligomer, active ingredient 30 wt%) was used after the diluting solvent was removed. Moreover, cyclohexanone was used as an oil-based solvent.

Using the above materials, an oil-based solvent-based dispersion of polytetrafluoroethylene was prepared by the formulation shown in Table 1 below. In the preparation, the fluorine-based additive was sufficiently stirred and mixed in the oil-based solvent, and then polytetrafluoroethylene micropowder was added and further stirred and mixed.

The mixed solution of polytetrafluoroethylene micropowder obtained as described above was dispersed with zirconia beads having a diameter of 0.3 mm using a horizontal bead mill.

The obtained dispersion was subjected to filter filtration in order to remove coarse particles of 1 µm or larger to obtain an oil-based solvent dispersion of polytetrafluoroethylene.

(Example 2)

A dispersion was prepared in the same manner as in Example 1, except that the amounts of the polytetrafluoroethylene micropowder and the fluorine-based additive were varied and the diameter of the zirconia beads was 1 mm.

(Example 3)

A dispersion was prepared in the same manner as in Example 1, except that the average particle diameter of the polytetrafluoroethylene micropowder was 0.8 µm.

(Example 4)

A dispersion was prepared in the same manner as in Example 1, except that KM-72 (0.05% by mass) manufactured by Shin-Etsu Silicones as a silicone-based antifoaming agent was added after bead mill dispersion and sufficiently stirred and mixed, followed by filtration.

(Example 5)

A dispersion was prepared in the same manner as in Example 1, except that propylene glycol monomethyl ether acetate (PGMEA) was used as an oil-based solvent.

(Example 6)

The dispersion was prepared in the same manner as in Example 1, except that Megapack F-563 manufactured by DIC Corporation (a fluorinated group/lipophilic group-containing oligomer) was used as 9 mass % as the fluorine-based additive and methyl ethyl ketone was used as the oil-based solvent. made

(Example 7)

A dispersion was prepared in the same manner as in Example 1, except that cyclohexanone was used by forcibly adding water as an oil-based solvent.

(Example 8)

Disperse in the same manner as in Example 1, except that Megapack F-555 (oligomer containing fluorinated, hydrophilic, and lipophilic groups, active ingredient 30 wt%) manufactured by DIC Corporation as a fluorine-based surfactant was used after removing the diluting solvent. sieve was made

(Comparative Example 1)

After preparing a dispersion in the same manner as in Example 1, water was forcibly added to obtain a dispersion.

(Comparative Example 2)

A dispersion was prepared in the same manner as in Example 1, except that the average particle diameter of the polytetrafluoroethylene micropowder was 1.2 µm and that filtration was not performed after dispersion.

(Comparative Example 3)

A dispersion was prepared in the same manner as in Example 1, except that water was forcibly added to cyclohexanone and sufficiently stirred as an oil-based solvent.

(Comparative Example 4)

The dispersion was prepared in the same manner as in Example 1, except that the amount of Megapack F-558 of the fluorine-based additive was 0.025% by mass (to polytetrafluoroethylene micropowder, less than 0.1% by mass). made

(Comparative Example 5)

In the same manner as in Example 1, except that 75% by mass of polytetrafluoroethylene micropowder was added, and Megapack F-563 (oligomer containing fluorinated and lipophilic groups) manufactured by DIC Corporation was used as a fluorine-based additive. An attempt was made to prepare a dispersion.

(Comparative Example 6)

After preparing a dispersion in the same manner as in Example 1, water was forcibly added to obtain a dispersion.

(Comparative Example 7)

A dispersion was attempted in the same manner as in Example 1, except that 75% by mass of polytetrafluoroethylene micropowder was added.

For the oil-based solvent-based dispersions of polytetrafluoroethylene obtained in Examples 1 to 8 and Comparative Examples 1 to 7, the dispersion fluidity, 25° C., and redispersibility after storage for 1 month were evaluated according to the following evaluation methods. The vesicle properties were evaluated.

These results are shown in Table 1 below.

(Method for evaluating the fluidity of the dispersion)

When each obtained oil-based solvent dispersion of polytetrafluoroethylene is dripped on PET film with a dropper, the dispersion expands, and movement of the dispersion when it is sharply tilted 90 degrees from a stationary state in a bottle From the state of , the following evaluation criteria evaluated visually.

Evaluation standard:

○: It flows smoothly.

(triangle|delta): It has structural viscosity.

x: It hardly flows.

(Method for evaluating redistribution)

Each of the obtained oil-based solvent-based dispersions of polytetrafluoroethylene was placed in a glass container with a lid (30 ml, hereinafter the same), and the redispersibility after storage at 25°C for one month was evaluated according to the following evaluation criteria.

Evaluation standard:

○: It is easily redistributed.

△: Redisperse.

x: sufficient stirring is required for redispersion.

(Method of evaluation of vesicle properties)

Each of the obtained oil-based solvent dispersions of polytetrafluoroethylene was sealed in a glass container with a lid, thoroughly stirred up and down, left and right, and the state of the foam after standing for 2 minutes was evaluated according to the following evaluation criteria.

Evaluation standard:

○: Almost disappeared.

△: Remains.

×: It does not disappear.

It became clear from said Table 1 that Examples 1-8 which were in the range of this invention also had favorable fluidity|liquidity of a dispersion, and storage stability was high. Example 7, which is within the scope of the present invention, was able to be redispersed even after storage at 25° C. for 1 month, but for Comparative Examples 1 and 3 and 5 with a moisture content exceeding 20000 ppm, sufficient stirring was required for redispersion. . Moreover, it became clear that Example 4 containing an antifoamer also had favorable foam disappearance.

On the other hand, it became clear that Comparative Examples 1-7 used outside the range of this invention are inferior to fluidity|liquidity and storage stability. Moreover, in Comparative Examples 5 and 7, since there was much polytetrafluoroethylene micropowder at 75 mass %, it was not able to disperse|distribute.

[Test Example 1: Test for adding resist material]

Further, using the polytetrafluoroethylene oil-based solvent dispersion for resist material addition obtained in Example 5, referring to Patent Documents 6 and 7, etc., mixed with a photosensitive resin composition having a photopolymerizable monomer It became clear that pattern formation was possible by carrying out exposure development after thin film formation. Further, as a result of measuring the dielectric constant of the cured film, it was also found that the reduction of the dielectric constant according to the amount of addition can be adjusted.

[Test Examples 2-5: Test for adding epoxy resin material]

Further, using the oil-based solvent-based dispersion of polytetrafluoroethylene obtained in Example 1 above, after mixing with the epoxy resin material in the respective blending amounts shown in Table 2 below, the oil-based solvent is removed by heating, and at a temperature of 180 ° C. It was cured for 8 hours to obtain a cured product.

About the obtained epoxy hardened|cured material of each of Test Examples 2-5, the dielectric constant at 23 degreeC and 1 GHz was measured using the material analyzer 4291B (made by Agilent Technologies).

These results are shown in Table 2 below.

Each of the cured epoxy products of Test Examples 2 to 5 shown in Table 2 can be cured, and from Test Example 2 that does not contain the polytetrafluoroethylene oil-based dispersion, the addition amount of Comparative Examples 3 to 5 increases Accordingly, it was also found that the relative dielectric constant could be reduced.

The oil-based solvent dispersion of polytetrafluoroethylene in the present invention is composed of various resin materials, for example, a resist material used for a color filter or black matrix, an epoxy resin material used for electronic devices, etc.; It is uniformly added to each material such as material, insulating material, rubber, adhesive, lubricant or grease, printing ink or paint, etc. to improve electrical properties or to impart the properties of polytetrafluoroethylene and to improve various product properties. It can be used, and it can be used for electronic devices, sliding materials, automobiles, kitchen appliances, and the like.

Claims (6)

5 to 70 mass% of polytetrafluoroethylene micropowder having a primary particle diameter of 1 μm or less, 0.1 to 40 mass% of a fluorine-based additive containing at least a fluorine-containing group and a lipophilic group, based on the mass of polytetrafluoroethylene micropowder; and an oil-based solvent, wherein the total moisture content by the Karl-Fischer method is 20000 ppm or less, An oil-based solvent-based dispersion of polytetrafluoroethylene. The method according to claim 1,
The oil-based solvent dispersion of polytetrafluoroethylene, characterized in that the water content of the oil-based solvent used in the oil-based solvent dispersion is 20000 ppm or less by Karl-Fischer method. The method according to claim 1 or 2,
The oil-based solvent used in the oil-based solvent dispersion is γ-butyrolactone, acetone, methyl ethyl ketone, hexane, heptane, octane, 2-heptanone, cycloheptanone, cyclohexanone, cyclohexane, methylcyclohexane, Ethylcyclohexane, methyl-n-pentyl ketone, methyl isobutyl ketone, methyl isopentyl ketone, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, ethylene glycol monoacetate, ethylene glycol monomethyl ether acetate, ethylene glycol mono Ethyl ether acetate, diethylene glycol monoacetate, diethylene glycol diethyl ether, propylene glycol monoacetate, dipropylene glycol monoacetate, propylene glycol diacetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl Ether acetate, cyclohexyl acetate, ethyl 3-ethoxypropionate, dioxane, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, anisole , ethylbenzyl ether, crezyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butylphenyl ether, benzene, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, Methanol, ethanol, isopropanol, butanol, methyl monoglycidyl ether, ethyl monoglycidyl ether, butyl monoglycidyl ether, phenyl monoglycidyl ether, methyl diglycidyl ether, ethyl diglycidyl ether, Butyl diglycidyl ether, phenyl diglycidyl ether, methylphenol monoglycidyl ether, ethylphenol monoglycidyl ether, butylphenol monoglycidyl ether, mineral spirit, 2-hydroxyethyl acrylate, tetra Hydrofurfuryl acrylate, 4-vinylpyridine, N-methylpyrrolidone, 2-ethylhexyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate, neopentyl One solvent selected from the group consisting of glycol diacrylate, hexanediol diacrylate, trimethylolpropane triacrylate, methacrylate, methyl methacrylate, and styrene, or two or more of these solvents An oil-based solvent-based dispersion of polytetrafluoroethylene, characterized in that it contains. The method according to claim 1,
An oil-based solvent-based dispersion of polytetrafluoroethylene, wherein the polytetrafluoroethylene micropowder in the oil-based solvent-based dispersion has an average particle diameter of 1 µm or less by laser diffraction/scattering method or dynamic light scattering method. The method according to claim 1,
An oil-based solvent-based dispersion of polytetrafluoroethylene, further comprising a silicone-based antifoaming agent. The oil-based solvent dispersion of polytetrafluoroethylene according to claim 1 is for adding a resist material or for adding an epoxy resin material.