JP2004285361A - Organosol dispersed in fluorine-containing solvent and its application - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organosol which is useful to disperse an inorganic fine powder in a fluorine-containing polymer, to provide a composition obtained by dissolving a fluorine-containing polymer in the organosol, and to provide a coating agent comprising them. <P>SOLUTION: This organosol is obtained by dispersing an inorganic fine powder treated with a fluorine-containing surface treatment agent such as a silane coupling agent and the like in an aprotic fluorine-containing solvent or in a mixed solvent of this solvent and a protic fluorine-containing solvent. A composition is obtained by dissolving an amorphous perfluoropolymer in this organosol. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an organosol in which inorganic fine particles are dispersed in a fluorine-containing solvent, a composition in which a fluorine-containing polymer is dissolved in the organosol, and use thereof.

  The fluorine-containing polymer is generally excellent in heat resistance and chemical resistance, and has a characteristic that the refractive index and dielectric constant are small. However, since it is soft, it has a disadvantage that the surface is easily damaged. As a method of overcoming such disadvantages, a method of filling the polymer with hard inorganic fine particles is effective. In addition, in order to obtain a molded body such as a thin film having a smooth surface, optically transparent and homogeneous, it is required to uniformly fill the polymer with fine particles having an average particle diameter of 1 μm or less that hardly scatter light. .

  Generally, when filling with inorganic fine particles, a method of mixing inorganic fine particle powder into a polymer is performed. However, when the inorganic fine particle powder is used, even if the primary particle size is small, it is easy for the particles to adhere to each other to form large secondary particles, so that a molded article having a smooth surface, optically transparent and homogeneous can be obtained. Is difficult.

  As a method for coping with this problem, a method in which inorganic fine particles uniformly dispersed in a liquid are used and inorganic fine particles are blended into a polymer is known. For example, a liquid composition composed of an organosol in which silica fine particles are dispersed in alcohol and a thermosetting resin is cured to obtain a hard and transparent molded body in which silica fine particles are uniformly dispersed (Patent Document 1). However, normal solvents used in organosols do not dissolve fluorine-containing polymers, so when the polymer is a fluorine-containing polymer, organosols using ordinary solvents cannot be used for the purpose of uniformly filling inorganic fine particles. .

JP-A-57-128760

  In order to uniformly mix inorganic fine particles such as silica fine particles with an amorphous perfluoropolymer soluble only in a specific fluorine-containing solvent, it is conceivable to use an organosol of inorganic fine particles using a fluorine-containing solvent. However, such an organosol has not been known so far, and it is difficult to obtain an organosol in which inorganic fine particles are uniformly and stably dispersed by simply changing the usual solvent used in the conventional organosol to this fluorine-containing solvent. Met.

The present invention relates to an organosol useful for blending inorganic fine particles with a fluorine-containing polymer, a composition in which the fluorine-containing polymer is dissolved in the organosol, and a coating agent comprising the same.
An organosol in which inorganic fine particles treated with a fluorine-containing surface treatment agent are dispersed in an aprotic fluorine-containing solvent having a boiling point of 30 ° C to 200 ° C.
An organosol in which inorganic fine particles treated with a fluorine-containing surface treatment agent are dispersed in a mixed solvent of an aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. and a protic fluorine-containing solvent.
A composition comprising a fluorine-containing polymer dissolved in the organosol.
A coating agent comprising the above organosol or a coating agent comprising the above composition.

  According to the present invention, conventional fluorine-containing polymers are not sufficient for various applications such as low reflection coatings and optical fibers that make use of the low refractive index of fluorine-containing polymers, and electronic materials that make use of the low dielectric constant of fluorine-containing polymers. The physical and mechanical properties can be improved. Further, since it contains colloidal particles, it is effective in preventing sagging during coating by utilizing thixotropic properties. When the organosol of the present invention containing a (meth) acrylate containing an Rf group as a fluorine-containing polymer is used, a water- and oil-repellent coating having excellent durability can be applied.

  In the present invention, the aprotic fluorine-containing solvent is a fluorine-containing solvent that does not dissociate under normal reaction conditions and does not generate protons. The protic fluorine-containing solvent is a fluorine-containing solvent that easily dissociates and generates protons, such as a fluorine-containing alcohol.

  The inorganic fine particles are fine particles having an average particle diameter of 1 μm or less made of an inorganic material. The fluorine-containing surface treatment agent is a compound that can be chemically or physically bonded to the surface of the inorganic fine particles and has a fluorine-containing group. A typical fluorine-containing surface treatment agent is a fluorine-containing silane coupling agent having a perfluoroalkyl group. These will be described in detail later. In the present invention, the “dispersion medium” of the organosol is also referred to as a solvent, but does not mean that the sol is dissolved.

The organosol of the present invention (hereinafter, organosol is also simply referred to as sol) can be produced by the following method. However, the manufacturing method is not limited to these. Basically, the inorganic sol using a conventional solvent is treated with a fluorine-containing surface treatment agent and then the solvent is replaced with a fluorine-containing solvent, and the organosol using the fluorine-containing solvent is produced. Then, there is a method in which the inorganic fine particles are surface-treated with a fluorine-containing surface treatment agent. Further, as a solvent replacement method, a method of drying a sol and then redispersing in a different solvent, a method of mixing two solvents, and then removing one of the solvents by distillation or the like using a boiling point temperature difference, There is a method in which one solvent is removed by ultrafiltration after mixing the two solvents.
Also, as the raw material sol, an aqueous sol (water alone or a mixture of water and an organic solvent as a dispersion medium) can be used.

More specifically, there are the following methods (1) and (2). However, when the solvent is distilled off from the raw material sol, the particles adhere to each other and are difficult to redisperse. Therefore, the method (2) is usually preferable to the method (1).
(1) A method in which the inorganic fine particles of the raw material sol are surface-treated with a fluorine-containing surface treatment agent, the solvent is then distilled off, and then the obtained solid content is dispersed in the fluorine-containing solvent.
(2) A method in which inorganic fine particles of the raw material sol are surface-treated with a fluorine-containing surface treatment agent, then a fluorine-containing solvent is added, and then one solvent is removed by distillation or by ultrafiltration.

  When the boiling point of the solvent of the raw material sol is lower than the boiling point of the fluorine-containing solvent, distillation separation is easy and preferable. Solvent replacement by ultrafiltration is used when distillation separation is difficult (for example, when the boiling point of the solvent of the raw material sol is higher than the boiling point of the fluorinated solvent or the difference between the boiling points is small). The solvent can be replaced by repeating concentration by ultrafiltration. In some cases, solvent replacement can be performed by combining distillation and ultrafiltration. A method of replacing the dispersion medium from water to an organic solvent by ultrafiltration is known (see, for example, Japanese Patent Publication No. 2-1087).

  The organic solvent for the raw material sol is usually an organic solvent compatible with water, such as alcohols such as methanol, ethanol, isopropyl alcohol, cellosolve, or dimethylformamide. Use of organosols using such organic solvents is preferred.

In the methods (1) and (2) , an aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. is used as the fluorine-containing solvent. However, an aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. may have low compatibility with the solvent of the raw material sol. In this case, it is preferable to use a protic fluorine-containing solvent that is soluble in both the solvent of the raw material sol and the aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. as a compatibilizing agent. That is, in the method (2), it is preferable to use a protic fluorine-containing solvent together with an aprotic fluorine-containing solvent having a boiling point of 30 to 200 ° C. as the fluorine-containing solvent.

Not only using a protic fluorine-containing solvent for solvent replacement, but also using an aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. and a protic fluorine-containing solvent to improve dispersion stability. Is preferred. For example, in the above method (2), when solvent substitution is carried out using a protic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. and a protic fluorine-containing solvent, the protic fluorine-containing solvent is also used together with the raw material sol solvent. When it is removed, it is preferable to re-add the protic fluorine-containing solvent to the obtained aprotic fluorine-containing solvent organosol having a boiling point of 30 ° C to 200 ° C.

  As described above, the organosol of the present invention can also be produced by the following method (3).

  (3) A method in which an organosol using a fluorine-containing solvent is produced, and then the inorganic fine particles are surface-treated with a fluorine-containing surface treatment agent.

This organosol is easy to surface-treat with a fluorine-containing surface treatment agent, and phase separation is difficult when part or all of the protic fluorine-containing solvent is replaced with an aprotic fluorine-containing solvent having a boiling point of 30 ° C to 200 ° C. The final obtained organosol has advantages such as high dispersion stability. Optionally manufactures organosol using the aprotic fluorine-containing solvent and the protic fluorine-containing solvent having a boiling point of 30 ° C. to 200 DEG aprotic fluorinated solvent or a boiling point of 30 ° C. to 200 DEG ° C. in ° C. is subjected to a surface treatment Finally, the desired organosol can be produced.

In the case of the organosol using the above protic fluorine-containing solvent, it is necessary to replace part to all of the solvent with an aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. after the surface treatment. As the solvent replacement method, the solvent replacement method by distillation or ultrafiltration described in the method (2) can be employed.

  As a method for producing an organosol using a fluorine-containing solvent from the raw material sol, the solvent replacement method as described above can be employed. For example, using a fluorine-containing alcohol that is a protic fluorine-containing solvent, an aqueous sol or organosol of inorganic fine particles is directly mixed with a fluorine-containing alcohol, and when the fluorine-containing alcohol has a higher boiling point than a non-fluorine solvent, By removing the solvent of the raw material sol by distillation, a sol in which inorganic fine particles are dispersed in a fluorine-containing alcohol can be produced.

  Also, a similar sol can be produced by mixing an aqueous sol or organosol directly with a fluorinated alcohol, and repeatedly performing concentration by ultrafiltration and addition of the fluorinated alcohol to remove the solvent of the raw material sol. Further, the sol can be concentrated by distilling off the fluorine-containing alcohol as necessary.

  Typical examples of the material of the inorganic fine particles in the organosol of the present invention are listed below. These can be used alone or in combination of two or more. In particular, metal oxides are preferred because of their high reactivity with fluorine-containing surface treatment agents. Preferred are silica, titania, alumina, zinc oxide, zirconia and tin oxide, and among these, silica, titania and alumina are particularly preferred. Further, the above or other inorganic fine particles can be selected and used according to the purpose. For example, it is preferable to use tin oxide for imparting conductivity and zinc oxide or titania for imparting ultraviolet absorption.

  Silica, titania, alumina, zinc oxide, zirconia, cerium oxide, tin oxide, talc, sericite, kaolin, iron oxide, mica, magnesium oxide, calcium carbonate, magnesium carbonate, calcium phosphate, aluminum hydroxide, barium sulfate, silica alumina, Antimony oxide, aluminum silicate, magnesium silicate, calcium silicate, alumina calcium carbonate, iron titanate, barium titanate, magnesium silicate aluminate, magnesium magnesium metasilicate, loess, yellow iron oxide, mango violet, cobalt violet , Chromium oxide, chromium hydroxide, cobalt titanate, bitumen, ultramarine. Metals such as aluminum and copper.

  The particle size of the inorganic fine particles in the organosol of the present invention is not particularly limited as long as it can be obtained as a raw material sol, and is usually an average particle size of 1000 nm or less, preferably 500 nm or less. In general, organosols having inorganic fine particles having an average particle diameter in the range of 5 nm to 500 nm are easily available. Furthermore, an organosol having inorganic fine particles having an average particle diameter of 100 nm or less is particularly preferred in the present invention because a molded article having particularly excellent transparency can be obtained. The proportion of the inorganic fine particles in the organosol of the present invention is 0.01 to 30% by weight, preferably 0.1 to 20% by weight.

  A silica sol that is generally easily available as a raw material sol is silica, and silica is a preferred inorganic fine particle in the present invention. A commercially available silica sol can be used, but is not limited thereto. For example, a silica sol synthesized by hydrolyzing and condensing a hydrolyzable silane such as tetraalkoxysilane in an organic solvent compatible with water can be used.

  The fluorine-containing surface treatment agent used in the present invention is a compound that can be chemically or physically bonded to the surface of inorganic fine particles, has a fluorine-containing group, and the surface of the inorganic fine particle is made to be a fluorine-containing group by the fluorine-containing group. It is a compound that can be solvated (enhance affinity for fluorine-containing solvents). The fluorine-containing group is preferably a chain-like relatively long polyfluoroorganic group, particularly a chain-like organic group containing a large number of difluoromethylene groups. Particularly preferred fluorine-containing groups are organic groups having the following Rf group. The group capable of binding to the surface of the inorganic fine particles is preferably a hydrolyzable metal group such as a hydrolyzable silyl group. Examples of the metal include titanium and aluminum in addition to silicon.

  A preferred fluorine-containing surface treatment agent in the present invention is a fluorine-containing silane coupling agent. A fluorine-containing silane coupling agent means the silane coupling agent which has the said fluorine-containing group.

  A silane coupling agent refers to a compound having one or more silyl groups having 1 to 3 hydrolyzable groups. As the hydrolyzable silyl group, a silyl group having 2 to 3 hydrolyzable groups is preferable, and a silyl group having 3 hydrolyzable groups is most preferable. Examples of hydrolyzable groups include alkoxy groups, alkoxyalkoxy groups, acyloxy groups, aryloxy groups, aminoxy groups, amide groups, ketoxime groups, isocyanate groups, halogen atoms, etc., and monohydric alcohols such as alkoxy groups and alkoxyalkoxy groups. A group in which a hydrogen atom of a hydroxyl group is removed is preferable. The alkoxy group is most preferably an alkoxy group, and the alkoxy group is preferably an alkoxy group having 4 or less carbon atoms such as a methoxy group or an ethoxy group. The silyl group has an organic group bonded to 1 to 3 silicon atoms (total 4 with hydrolyzable groups), and usually an organic group in which at least one, particularly only one, has a functional group It is. The organic group other than the organic group having a functional group is usually an alkyl group such as a methyl group.

  The fluorine-containing silane coupling agent has the fluorine-containing group as the organic group having the functional group. In particular, those having an organic group having an Rf group as described below are preferred.

  Examples of the fluorine-containing silane coupling agent include the following compounds.

_{Rf (CH 2) k SiX 3} [k = 1~5],
Rf (CH ₂ ) _k Si (R ¹ ) X ₂ [k = 1 to 5],
RfCONHSSiX ₃ ,
RfCONH (CH ₂ ) ₂ SiX ₃ ,
RfCONH (CH ₂ ) ₃ SiX ₃ ,
_{RfSO 2 NHCH 2 CH 2 N (} SO 2 Rf) (CH 2) 3 SiX 3,
RfSO ₂ NH (CH ₂ ) ₂ SiX ₃ ,
RfSO ₂ NH (CH ₂ ) ₂ Si (R ¹ ) X ₂ ,
RfSO ₂ NH (CH ₂ ) ₃ SiX ₃ ,
RfSO ₂ NH (CH ₂ ) ₃ Si (R ¹ ) X ₂ ,
RfCOO (CH ₂ ) ₂ SiX ₃ ,
RfCOO (CH ₂ ) ₂ Si (R ¹ ) X ₂ ,
RfO (CH ₂ ) ₃ Si (R ¹ ) X ₂ ,
RfO (CH ₂ ) ₃ SiX ₃ ,
(Rf (CH ₂ ) ₂ ) ₂ SiX ₂ ,
_{Rf (CH 2) k Si (} NH 2) 2 NHSi ((CH 2) k Rf) (NH 2) 2 [k = 1~5],
_{Rf (CH 2) k Si (} NH 2) 2 NHSi ((CH 2) k Rf) (NH 2) NHSi ((CH 2) k Rf) (NH 2) 2 [k = 1~5].

  Further, as the fluorine-containing surface treatment agent other than the fluorine-containing silane coupling agent, silicone having a fluorine-containing group, polysiloxane, phosphate ester, or the like may be used. For example, the following compounds disclosed in JP-A-3-188812 can be employed.

In the above, Rf represents a perfluoroalkyl group having a linear or branched structure having 1 to 21 carbon atoms. R ¹ is a monovalent organic group which may be the same as or different from each other. R ² represents a hydrogen atom or a monovalent organic group. X represents a hydrolyzable group. n is an integer of 1 or more, preferably 1 to 5000, and m is an integer of 3 or more, preferably 3 to 12. Moreover, two or more kinds of fluorine-containing surface treatment agents as described above can be used in combination.

  Examples of the Rf group include the following. U is 1 to 21, v is 0 to 18, and w is 1 to 5. Moreover, you may use the compound by which the fluorine atom of Rf group was partially substituted by the hydrogen atom or the chlorine atom.

F (CF ₂ ) _u −,
(CF ₃ ) ₂ CF (CF ₂ ) _v −,
_{CF 3 (CF 2) 2 O} (CF (CF 3) CF 2 O) w CF (CF 3) -,
_{F (CF 2) u-1} O (CF 2) 2 -,
_{CF 3 (CF 2) 2 O} (CF (CF 3) CF 2) w + 1 O (CF 2) 2 -.

In the fluorinated silane coupling agent having a linear perfluoroalkyl group (F (CF ₂ ) _u —), u is preferably 4 to 12, and particularly excellent in stability and transparency when u = 6 to 10. An organosol is obtained.

The most preferable fluorine-containing surface treatment agent in the present invention contains a compound represented by the formula RfC ₂ H ₄ SiX _{3 wherein} X is a methoxy group or an ethoxy group, and Rf is a linear perfluoroalkyl group having 4 to 16 carbon atoms. Fluorine silane coupling agent.

  The method for treating inorganic fine particles using a fluorine-containing surface treatment agent such as a fluorine-containing silane coupling agent is usually carried out by adding the fluorine-containing surface treatment agent to the organosol and holding it between cooling to room temperature to heating. The treatment is usually performed at 0 ° C to 300 ° C, preferably 20 ° C to 200 ° C. The treatment is particularly preferably performed at a temperature from 40 ° C. to the reflux temperature of the solvent. By this treatment, the fluorine-containing surface treatment agent is bonded to the surface of the inorganic fine particles, the surface of the inorganic fine particles is converted into a fluorinated solvent, and a fluorine-containing solvent organosol having high dispersion stability is obtained.

  In the above treatment, the binding reaction of the fluorine-containing surface treating agent to the inorganic fine particles can be promoted by adding water, an acid or a base as necessary. Usually, acids such as acetic acid, hydrochloric acid, sulfuric acid, p-toluenesulfonic acid and bases such as ammonia are used, but not limited thereto.

  Furthermore, it can also process using a reactive adjuvant. As the reactive assistant, for example, compounds such as organic titanates, aluminum alcoholates, aluminum chelates, and cyclic aluminum oligomers as described in JP-A-1-197420 can be used. Specific examples include tetraisopropyl titanate, tetra-n-butyl titanate, diisopropoxy (acetylacetonato) titanium, aluminum triisopropoxide, aluminum-sec-butyrate, aluminum tris (acetylacetonate) and the like. .

  The amount of the fluorine-containing surface treatment agent used is preferably an effective amount of 1 part by weight or more, more preferably 10 to 200 parts by weight, and particularly preferably 20 to 100 parts by weight with respect to 100 parts by weight of the inorganic fine particles. When the amount used is small, it becomes difficult to finely and stably disperse the inorganic fine particles in the fluorine-containing solvent, which causes white turbidity and solid analysis. As the amount used increases, the stability increases, but the content of inorganic fine particles in the molded product obtained by coating or the like is relatively reduced, and the effect of adding inorganic fine particles tends to be small.

The aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. used as a dispersion medium in the present invention is a solvent that does not dissociate and does not generate protons under normal reaction conditions. The aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. is preferably one that can dissolve the fluorine-containing polymer. Among the fluorine-containing polymers, those capable of dissolving an amorphous perfluoropolymer such as a polymer having a fluorine-containing aliphatic ring structure are preferable. Furthermore, considering the case where the solvent is released into the atmosphere during molding, the aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. is preferably a fluorine-containing solvent containing no chlorine atom in consideration of the environment.

In particular, (a) a fluorine-containing solvent comprising a hydrogen atom, fluorine atom, carbon atom, oxygen atom, (b) a fluorine-containing solvent comprising a hydrogen atom, fluorine atom, carbon atom, nitrogen atom, or (c) a hydrogen atom, fluorine A fluorine-containing solvent consisting only of atoms and carbon atoms is preferred. Further, aprotic fluorine-containing solvent or a mixture of boiling point 30 to 200 ° C. is used.

Specific examples of the aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. are listed below, but are not limited thereto. These aprotic fluorine-containing solvents can be used alone or as a mixture of two or more.

  Fluorine-containing aromatic hydrocarbons such as perfluorobenzene, pentafluorobenzene, 1,3-bis (trifluoromethyl) benzene, and 1,4-bis (trifluoromethyl) benzene. Fluorine-containing alicyclic hydrocarbons such as perfluorodecalin, perfluorocyclohexane, and perfluoro (1,3,5-trimethylcyclohexane). Fluorine-containing alkylamines such as perfluorotributylamine and perfluorotripropylamine. Fluorine-containing cyclic ethers such as perfluoro (2-butyltetrahydrofuran). Fluorinated polyethers such as fluorine-containing low molecular weight polyethers. Fluorinated ketones such as bis (heptafluoroisopropyl) ketone.

  Perfluorohexane, perfluorooctane, perfluorodecane, perfluorododecane, perfluoro (2,7-dimethyloctane), 3,3-dichloro-1,1,1,2,2-pentafluoropropane, 1,3-dichloro-1, 1,2,2,3-pentafluoropropane, perfluoro (1,2-dimethylhexane), perfluoro (1,3-dimethylhexane), 2H, 3H-perfluoropentane, 1H-perfluorohexane, 1H-perfluorooctane, 1H -Perfluorodecane, 1H, 1H, 1H, 2H, 2H-perfluorohexane, 1H, 1H, 1H, 2H, 2H-perfluorooctane, 1H, 1H, 1H, 2H, 2H-perfluorodecane, 3H, 4H-perfluoro-2 -Methylpentane, 2H, 3H-pe Fluorinated aliphatic hydrocarbons such as fluoro-2-methyl pentane.

The protic fluorine-containing solvent is a fluorine-containing solvent that easily dissociates and generates protons, such as a fluorine-containing alcohol. As described above, in order to finely disperse the inorganic fine particles and improve transparency, it is effective to use a protic fluorine-containing solvent and an aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. in combination as the dispersion medium. is there. However, since the protic fluorine-containing solvent has a low ability to dissolve the fluorine-containing polymer, only the protic fluorine-containing solvent is used, or the fluorine-containing polymer containing a high proportion of the protic fluorine-containing solvent is used. When this organosol is used for coating, there is a risk of uneven coating on the coating film. Therefore, when the protic fluorine-containing solvent is used in combination with an aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C., it is necessary to adjust the type and amount according to the purpose.

As described above, in order to increase the transparency by finely dispersing inorganic fine particles, it is effective to add a protic fluorine-containing solvent such as fluorine-containing alcohol to the dispersion medium. However, an organosol in which a polymer is dissolved is used. In the case where uneven coating occurs in the resulting film, it may be better to use an aprotic fluorinated solvent having a single boiling point of 30 ° C. to 200 ° C. as the dispersion medium. When a protic fluorine-containing solvent is used, two or more kinds can be used.

When a protic fluorine-containing solvent is used, the amount of the aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. and the amount of the protic fluorine-containing solvent is 0.01 to 50% by weight is suitable and 0.1-30% by weight is preferred. However, when the protic fluorine-containing solvent is a fluorine-containing alcohol, it may be used in a larger amount, and the upper limit is preferably 80% by weight. The most preferred proportion of the protic fluorine-containing solvent including the case of fluorine-containing alcohol is 1.0 to 30% by weight. An increase in the proportion of the protic fluorine-containing solvent is advantageous in terms of the stability of the organosol, but as mentioned above, the solubility of the fluorine-containing polymer is lowered, which may cause white turbidity and precipitation.
If the dispersion stability is low or there is a possibility that white turbidity or precipitation may occur due to a decrease in the solubility of the fluorine-containing polymer, this problem may be solved by using a fluorine-containing surfactant.

As the protic fluorine-containing solvent, a fluorine-containing alcohol is most preferable. As the fluorine-containing alcohol, for example, the following compounds can be used.
(CF ₃ ) ₂ CHOH,
_{F (CF 2) s (CH} 2) t OH [s = 1~12, t = 1~5],
(CF ₃ ) ₂ CF (CF ₂ ) _p (CH ₂ ) _q OH [p = 1 to 10, q = 1 to 5],
_{F (CF (CF 3) CF} 2 O) r CF (CF 3) CH 2 OH [r = 1~4].

  Examples of protic fluorine-containing solvents other than fluorine-containing alcohols include fluorine-containing carboxylic acids, fluorine-containing carboxylic acid amides, and fluorine-containing sulfonic acids. Specific examples of the compound include the following compounds.

  Trifluoroacetic acid, perfluoropropanoic acid, perfluorobutanoic acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, 3H-tetrafluoropropanoic acid, 5H-octafluoropentanoic acid, 7H-dodecafluoroheptanoic acid, 9H-hexadecafluorononanoic acid, amides of these fluorinated carboxylic acids, trifluoromethanesulfonic acid, hepadecafluorooctanesulfonic acid.

The composition of the present invention is obtained by dissolving a fluorine-containing polymer in the organosol of the present invention. The fluorine-containing polymer may be directly dissolved in the organosol. Further, a fluorine-containing polymer solution may be produced by dissolving in an aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. , and this solution and the organosol may be mixed. The amount of the fluorine-containing polymer in the composition of the present invention is not particularly limited as long as it is an amount capable of dissolving it. However, usually 0.01 to 30% by weight, particularly 0.1 to 20% by weight, based on the fluorine-containing solvent is preferable.

  As the fluorine-containing polymer, various fluorine-containing polymers that are soluble in a fluorine-containing solvent can be used. Examples of such a fluorine-containing polymer include an amorphous fluorine-containing polymer and a crystalline polymer having a melting point of room temperature or lower. In particular, amorphous fluorine-containing polymers are preferred for applications such as coating agents.

  As the amorphous fluorine-containing polymer, a fluorine-containing polymer having a fluorine-containing aliphatic ring structure is preferable, and among them, a perfluoropolymer having a fluorine-containing aliphatic ring structure is particularly preferable. Examples of the perfluoropolymer include poly (perfluorobutenyl vinyl ether), poly (perfluoropropenyl vinyl ether), a copolymer of perfluoro-2,2-dimethyl-1,3-dioxole and tetrafluoroethylene.

  Modified products of these polymers can also be used. For example, in order to improve the heat resistance of the polymer and the adhesion to the base material, the above polymer in which a functional group such as a carboxyl group is introduced at the end of the polymer is known (JP-A-4-226177). Such fluorine-containing polymers are also preferred in the present invention.

  Examples of other amorphous fluorine-containing polymers include hexafluoropropylene oxide homopolymers and perfluoropolyethers such as poly (perfluorotrimethylenediol).

  Examples of crystalline polymers include copolymers of tetrafluoroethylene and hexafluoropropylene, copolymers of hexafluoropropylene and vinylidene fluoride, copolymers of perfluoromethyl vinyl ether and tetrafluoroethylene, and perfluoropropyl vinyl ether and tetrafluoro. Examples include ethylene copolymers. These copolymers may become amorphous depending on the copolymer composition, and the amorphous polymer can also be used as the amorphous fluorine-containing polymer.

  Furthermore, as a fluorine-containing polymer other than the above, a homopolymer of the acrylate or methacrylate having the Rf group or a copolymer thereof with another monomer can be used. Such a polymer of (meth) acrylate having an Rf group is effective for imparting water repellency and oil repellency to the coated surface.

  The organosol or composition of the present invention is particularly useful as a coating agent. For example, this organosol can be used for applications such as antireflection coatings and hard coatings, and this composition can be used for antireflection coatings that take advantage of the low refractive index of fluorine-containing polymers, optical fiber manufacturing materials, low dielectric constants of fluorine-containing polymers. It is useful for various applications such as electronic materials that make good use of the rate.

  The organosol or composition of the present invention can be used by blending a film-forming agent, an adhesion improver, a surfactant, and other various compounding agents other than those described above depending on the application. For example, as the film forming agent, various polymers other than the above-mentioned fluorine-containing polymer and components that can become polymers can be blended.

  Examples of the compounding agent that can be blended into the organosol or composition of the present invention include the above-mentioned fluorine-containing surface treatment agent, particularly a fluorine-containing silane coupling agent. For the purpose other than the surface treatment of inorganic fine particles, for example, compounded as an adhesion improver. it can. However, it is preferable to use a silane coupling agent other than the fluorine-containing silane coupling agent for the purpose of improving the adhesion.

  For example, by adding a silane coupling agent to the surface-treated inorganic fine particle-dispersed amorphous fluorine-containing polymer solution that is the composition of the present invention, the shape can be maintained even at high temperatures and the adhesion to the substrate is good. A coating film is obtained. Since inorganic fine particles are contained, a hard coating film is obtained and excellent in scratch resistance. It is easy to control physical properties such as thermal expansion coefficient, dielectric constant, and refractive index by changing the mixing ratio. Since the contained particles are very fine, an optically transparent and homogeneous film can be obtained.

  The silane coupling agent other than the fluorine-containing silane coupling agent is a silane coupling agent having no fluorine-containing group, and is a hydrolyzable silane compound having at least one organic group. The at least one organic group is preferably an organic group having a functional group, and examples of the functional group include an amino group, an epoxy group, a mercapto group, an isocyanate group, and an unsaturated group.

  Such silane coupling agents can be used over a wide range including conventionally known or well-known ones. For example, the following can be used alone or in combination. A particularly preferred silane coupling agent is an amine-based silane coupling agent having an aliphatic or aromatic hydrocarbon group having at least one amino group. The amino group may be a primary or secondary amino group or a tertiary amino group.

  Monoalkoxysilanes such as trimethylmethoxysilane, trimethylethoxysilane, dimethylvinylmethoxysilane, and dimethylvinylethoxysilane.

  γ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane N- (β-aminoethyl) -γ-aminopropylmethyldiethoxysilane, aminophenylmethyldimethoxysilane, aminophenylmethyldiethoxysilane, aminophenylmethyldipropoxysilane, aminophenylmethyldiisopropoxysilane, aminophenylphenyl Dimethoxysilane, aminophenylphenyldiethoxysilane, aminophenylphenyldipropoxysilane, aminophenylphenyldiisopropoxysilane, N, N-dimethylaminophenylmethyldimethyl Toxisilane, γ-glycidyloxypropylmethyldimethoxysilane, γ-glycidyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, methyldimethoxysilane, methyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methylvinyl Dialkoxysilanes such as dimethoxysilane, methylvinyldiethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane.

  Vinyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-amino Propyltriethoxysilane, aminophenyltrimethoxysilane, aminophenyltriethoxysilane, aminophenyltripropoxysilane, aminophenyltriisopropoxysilane, N, N-dimethylaminophenyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ -Glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, methyltriethoxysila Trialkoxysilanes such as phenyltrimethoxysilane and phenyltriethoxysilane.

Depending on the silane coupling agent, the solubility in an aprotic fluorine-containing solvent having a boiling point of 30 ° C. to 200 ° C. is poor, so it may be difficult to mix the necessary amount of the silane coupling agent. In this case as well, a silane coupling agent in an amount necessary to achieve the object can be dissolved by using a protic fluorine-containing solvent such as a fluorine-containing alcohol.

  Although the compounding quantity of the silane coupling agent with respect to the composition of this invention is not specifically limited, 0.01-50 weight part is preferable per 100 weight part of fluoropolymers, Most preferably, it is 0.1-30 weight part. Further, the amount of the silane coupling agent to the organosol of the present invention is not particularly limited, but is preferably 0.01 to 50 parts by weight, particularly preferably 0.1 to 30 parts by weight per 100 parts by weight of the surface-treated inorganic fine particles. Part.

  The coating agent of the present invention can be used for various applications by taking advantage of its characteristics. For example, since a coating film having a low refractive index can be formed on a substrate, it can be used to produce an antireflective article. Examples of the base material used in this application include lenses, displays, solar cell windows, water heater windows, display front panels, vehicle windows, display windows, clock windows, frame covers, polarizing plates, and other parts. , Films, plates and the like.

  In addition, the coating agent of the present invention can be used for coating applications for moisture-proofing and insulating electronic materials that make use of a low dielectric constant. For example, it can be used to form a moisture-proof film or an interlayer insulating film in semiconductor or IC manufacturing. Further, it can be used as a material for a pellicle film or sealing. Furthermore, the organosol or composition of the present invention can be used in addition to a coating agent. In addition, if the inorganic fine particles are tin oxide or the like, conductivity can be imparted to the substrate, and if it is zinc oxide or titania, ultraviolet absorption ability can be imparted to the substrate.

  The abbreviations used in the following description and their contents are shown in Table 1.

"Example 1"
40 parts by weight of fluorine-containing surface treatment agent (F (CF ₂ ) ₆ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ ) is added to OSCAL per 100 parts by weight of silica. A 1% by weight aqueous acetic acid solution was added so that equimolar amount of water was added to the group, and the mixture was kept at 60 ° C. for 1 hour to obtain Solution A-1.
Next, this mixed solution was added to Solution A-1 so that the silica was 1.33 parts by weight with respect to 100 parts by weight of the mixed solution of TFE and PFD (weight ratio 1: 9).
By heating, the solvent was distilled off by heating until the boiling point became stable at the boiling point of PFD (distillation amount 35 parts by weight) to obtain a solution B-1 containing no IPA and TFE.
Next, a PBVE PFD solution (concentration 15 wt%) was added to solution B-1 to make the PBVE concentration 2 wt%, and the ratio (weight ratio) of PBVE / silica / fluorinated surface treatment agent was 51.8 / 34. 4 / 13.8 pale white translucent stable solution C-1 was obtained.

"Examples 2 to 5"
In Example 2, Solution B-1 ′ obtained in the same manner as in Example 1 was used except that the number of parts added of the fluorine-containing surface treatment agent in Example 1 was changed to 30 parts by weight. Further, except that the fluorine-containing surface treatment agent in Example 1 was changed to fluorine-containing trialkoxysilane as described in the columns of Examples 4 to 5 in Table 2, the solution B- 2, B-3 was obtained.
Next, to the solutions B-1 ′, B-1, B-2, and B-3, 5 parts by weight of TFE and a PFD solution of PBVE (concentration of 15% by weight) were added, so that the concentration of PBVE was 2% by weight. 2 to C-5 were obtained. The ratio (weight ratio) of PBVE / silica / fluorine-containing surface treatment agent was 53.6 / 35.7 / 10.7 in Examples 2, 4, and 5 and 51.8 / 34. 4 / 13.8. The transparency of the obtained solutions C-2 to C-5 is shown in Table 2. Solutions C-2 to C-5 correspond to Examples 2 to 5, respectively.

"Comparative Example 1"
When OSCAL was added so that the amount of silica was 1.33 parts by weight with respect to 100 parts by weight of a mixed solution of TFE and PFD (weight ratio 1: 9), white turbidity and precipitation were generated.

"Example 6, comparative example 2"
In Example 6, a solution C was prepared in the same manner as in Example 2 except that the ratio of the PBVE / silica / fluorinated surface treatment agent in Example 2 was changed as described in the column of Example 6 in Table 3. -6 was prepared. A PBVE concentration was 2% by weight, and a liquid with good stability and a light blue-purple color with high transparency was obtained. Next, this liquid was coated on a hard coat layer of a polycarbonate plate having an alkoxysilane hard coat layer, and pencil hardness and refractive index were evaluated. The results are shown in Table 3 together with Comparative Example 2 that does not contain silica and a fluorine-containing surface treatment agent.

"Example 7"
A solution B-4 containing no IPA and PFPA was obtained in the same manner as in Example 1 except that the mixed solution of TFE and PFD in Example 1 was changed to a mixed solution of PFPA and PBTF.
Next, PBVE PBTF solution (concentration 9% by weight) is added to solution B-4 to make the PBVE concentration 2% by weight, and the ratio (weight ratio) of PBVE / silica / fluorine-containing surface treatment agent is 58/30/12. A pale white and translucent stable solution C-7 was obtained.

"Example 8"
When 0.5 part by weight of PFPA was added to 99.5 parts by weight of the solution C-7 in Example 7, a light blue-purple and stable solution C-8 with high transparency was obtained.

"Example 9"
A solution C-9 was obtained in the same manner as in Example 6 except that PBVE ₂ was used instead of PBVE to prepare a coating film. The pencil hardness was 2H and the refractive index was 1.32.

"Example 10"
Instead of the solution C-9, the weight ratio of PBVE ₂ / fluorine-containing surface treatment agent (F (CF ₂ ) ₆ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ ) in the solution C-9 was changed to 86/10/4. A coating film was prepared in the same manner as in Example 9 except that the solution C-10 obtained as 72/20/8 was used. The pencil hardness was 3H and the refractive index was 1.34.

"Example 11"
The solution C-3 of Example 3 that did not contain PBVE was concentrated with an evaporator until the solid concentration became 10 times, but no precipitate was formed, and a stable solution B-5 was obtained.

"Example 12"
Ultrafiltration (fractionated molecular weight 50,000) until the concentration of water in the dispersion medium becomes 3% by weight or less while sometimes adding TFE to silica sol (silica 20% by weight, particle size 12 nm) using water as the dispersion medium. ) To prepare an organosol (silica 20% by weight) using TFE as a dispersion medium. 40 parts by weight of fluorine-containing surface treating agent (F (CF ₂ ) ₆ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ ) is added per 100 parts by weight of silica, and equimolar with the alkoxy group of this fluorine-containing surface treating agent. 1% by weight acetic acid aqueous solution was added so that water was added, and kept at 60 ° C. for 1 hour. Although 5 parts by weight of this organosol was added to 95 parts by weight of PFD, no precipitate was formed, and a solution B-6 in which silica was stably dispersed was obtained.

"Example 13"
40 parts by weight of fluorine-containing surface treatment agent (F (CF ₂ ) ₆ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ ) is added to OSCAL per 100 parts by weight of silica, and the alkoxy group of the silane coupling agent is added. 1% by weight acetic acid aqueous solution was added so that equimolar water was added and refluxed for 2 hours to obtain Solution A-2.

Next, this mixed solution was added to the solution A-2 so that silica was 1.16 parts by weight with respect to 100 parts by weight of the mixed solution of PFPA and PFD (weight ratio 1: 9).
By heating, the solvent was distilled off by heating until the boiling point became stable at the boiling point of PFD to obtain milky white solution B-7 containing no IPA and PFPA.
Next, PBVE PFD solution was added to solution B-7 to adjust the PBVE concentration to 10% by weight, and the ratio (weight ratio) of PBVE / silica / fluorine-containing surface treatment agent was 86/10/4. Solution C-11 was obtained.

"Example 14"
Fluorine-containing polymer in solution C-10 is 0.4 part of PBVE, polyfluoroacrylate (CH ₂ = CHCOOCH ₂ CH ₂ C _n F _{2n + 1} : n is 9 on average) homopolymer (number average molecular weight: 10,000) A solution C-12 was obtained in the same manner as in Example 10 except that the amount was 1.6 parts and the solvent was PBTF alone.

  Next, the glass plate cleaned by the ultrasonic cleaner was immersed in this solution and pulled up at a constant speed. When this glass plate was dried at 80 ° C. for 1 hour, a uniform coating film could be formed on the glass plate. This film had good abrasion resistance and showed water and oil repellency superior to the film obtained using Solution C-10.

"Example 15"
In 2 parts of the fluoropolymer of Example 14 (0.4 parts of PBVE / 1.6 parts of polyfluoroacrylate homopolymer), the weight ratio of PBVE to polyfluoroacrylate homopolymer was 2: 3, 3: 2, 4 A coating film was formed in the same manner as in Example 14 except that the ratio was set to 1. In any case, the abrasion resistance was good, and water and oil repellency superior to the film obtained using Solution C-10 was exhibited.

"Example 16"
This mixed solution was added to the solution A-1 so that the silica was 2.14 parts by weight with respect to 100 parts by weight of the mixed solution of PFPA and PFD (weight ratio 1: 9). By heating, the solvent was distilled off by heating until the boiling point became stable at the boiling point of PFD to obtain milky white solution B-8 containing no IPA and PFPA.

Next, PFD was added to solution B-8 to make the total amount 92.3 parts by weight, 7.7 parts by weight of PBVE ₁ was dissolved, and the concentration of PBVE ₁ was 7.7% by weight, and this PBVE ₁ / silica / containing A pale translucent stable solution C-13 having a fluorine surface treating agent ratio of 72/20/8 was obtained.

"Example 17"
To 30 g of Solution C-13, 0.11 g of γ-aminopropylmethyldiethoxysilane was added (hereinafter abbreviated as Solution D). To 6.65 g of this solution D, 0.35 g of PFHE was added. The solution viscosity (25 ° C., E-type viscometer) was 1265 cP. It spin-coated on the silicon wafer, and dried at 250 degreeC for 1 hour. The thickness of the coating film was 2.4 μm.

  When the tape peeling test was performed by the cross-cut tape method of JIS-K5400 about the obtained coating film, abnormality was not observed in the grid. In order to check the melt flow resistance, the solution D was similarly spin-coated on a silicon wafer, dried at 250 ° C. for 1 hour, put in a grid, and heat-treated at 300 ° C. for 1 hour. Observation under a microscope revealed no evidence of resin melting. Solution D was cast and dried at 200 ° C. In order to check the dissolution resistance, the obtained cast film was immersed in the solvent of the solution D at 60 ° C. for 1 week, but it did not dissolve and retained its shape.

"Example 18"
In the same manner as Solution D, Solution E having a ratio of PBVE ₁ / silica / fluorinated surface treatment agent of 58/30/12 and a PBVE ₁ concentration of 8.5% by weight was prepared. 0.12 g of γ-aminopropylmethyldiethoxysilane was added to 30 g of this solution E, cast onto a glass plate, and dried at 50 ° C. for 1 hour, 100 ° C. for 1 hour, and then 180 ° C. for 1 hour. The thickness of the coating film was 10 μm and the pencil hardness was 2H.

“Comparative Example 3”
A coating film having a thickness of 10 μm was obtained from a PBVE ₁ solution consisting only of PBVE ₁ and solvent PFD under the same conditions as in Example 18. The cast film had a pencil hardness of 2B.
"Example 19"
A solution having the same composition as Solution D was prepared except that the solvent was not PFD but a PFBA / PFHE (weight ratio 95/5) mixed solvent. To 30 g of this solution, 0.11 g of γ-aminopropylmethyldiethoxysilane was added, and the same test as in Example 17 was performed. The same results as in Example 17 were obtained for the tape peel test, melt flow resistance, and dissolution resistance.

  The organosol or composition of the present invention is particularly useful as a coating agent. For example, this organosol can be used for applications such as antireflection coatings and hard coatings, and this composition can be used for antireflection coatings that take advantage of the low refractive index of fluorine-containing polymers, optical fiber manufacturing materials, low dielectric constants of fluorine-containing polymers. It is useful for various applications such as electronic materials that make good use of the rate.

Claims (5)

  An organosol in which inorganic fine particles treated with a fluorine-containing surface treatment agent are dispersed in an aprotic fluorine-containing solvent.   An organosol in which inorganic fine particles treated with a fluorine-containing surface treatment agent are dispersed in a mixed solvent of an aprotic fluorine-containing solvent and a protic fluorine-containing solvent.   A coating agent comprising the organosol according to claim 1 or 2.   A composition comprising a fluoropolymer dissolved in the organosol according to claim 1 or 2. A coating agent comprising the composition according to claim 4.