JPH04122731A - Fine polyorganosilsesquioxane particle and its production - Google Patents

Abstract

PURPOSE:To facilitate the formation of the title particle excellent in abrasion resistance, water repellency and lubricity by forming a surface part comprising perfluoro-alkylenesilsesquioxane units around a core comprising polymethylsilsesquioxane units. CONSTITUTION:Methyltrialkoxysilane or its partial hydrolyzate is hydrolyzed in an aqueous alkali solution to form a core comprising polymethylsilsesquioxane units. A perfluoroalkyl-trialkoxysilane is added to the aqueous medium in which the cores are dispersed and hydrolyzed. In this way, a surface part comprising perfluoroalkylsilsesquioxane units is formed around the cores to obtain polyorganosilsesquioxane particles. When combined with a water repellent, an oil repellent or the like, the obtained particles can be used as a nonadhesive coating material, a cosmetic material, an additive to a polishing agent or the like.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a polyorganosolsesquioxane having a core portion consisting of polymethylsilsesquioxane units and a surface layer portion consisting of perfluoroalkylsilsesquioxane units. This invention relates to fine particles and their manufacturing method.

[Prior art and problems to be solved by the invention] Fine powders consisting of polymethylsilsesquioxane units have been known (Japanese Patent Publications No. 40-16917, No. 56-3).
No. 9808, Special Publication No. 2-22767, Japanese Unexamined Patent Publication No. 63-7
No. 7940, No. 63-295637), which has good fluidity, water repellency, and excellent compatibility with organic resins, so it can be used as a filler for organic resins, a water repellent, a moisture absorption inhibitor for powdered extinguishing agents, It is useful as a cosmetic additive, etc.

It is also known that the surface of such polymethylsilsesquioxane fine powder is treated with an organofunctional silane or the like to impart various functions (Japanese Patent Laid-Open No. 10185-1985).
No. 7, Japanese Unexamined Patent Publication No. 1-268609). In this case, these known surface treatment methods include adding polymethylsilsesquioxane fine powder to a surface treatment agent and adsorbing it, and pulverizing a mixture of polymethylsilsesquioxane fine powder and surface treatment agent. A method in which polymethylsilsesquioxane fine particles are added to an organic solvent solution of a surface treatment agent, a method in which polymethylsilsesquioxane fine particles are dispersed in an organic solvent solution, and then a surface treatment agent is added to the surface treatment agent. In addition, an adsorption method is employed, whereby functional groups are fixed on the surface of the polymethylsilsesquioxane fine powder.

However, in these methods, a surface treatment agent is simply applied to the inert surface of the polymethylsilsesquioxane fine powder, and reactive groups 1 in the surface treatment agent, such as alkoxy Although the silyl group is adsorbed, it is difficult to form a chemical bond between the two. Therefore, since the surface treatment agent remains adsorbed to the polymethylsilsesquioxane fine powder, it is susceptible to various deterioration conditions, such as extraction conditions due to contact with organic solvents, chemicals, and organic polymers. There is a risk that the surface treatment layer will fall off under conditions such as friction caused by contact with other solid objects.

On the other hand, as a solution to the problem of the surface treatment layer falling off, it has been proposed to use polyorganosolsesquioxane fine powder in which the hydrocarbon bonded to the silicon atom has 6 or less carbon atoms (particularly Kaihei 1-217039
Publication No.). However, in this proposal, although it is essentially impossible for organic functional groups to fall off, as the number of substituents bonded to silicon atoms increases, the crosslinking density in the fine powder decreases. The problem is that the strength of the body decreases.

The present invention was made in view of the above circumstances, and the surface layer is chemically bonded to the core of polymethylsilsesquioxane fine particles.
The object of the present invention is to provide polyorganosolsesquioxane fine particles whose surface layer part does not easily fall off, have high strength, have a low energy surface, and have excellent fluidity, dispersibility, and durability, and a method for producing the same.

[Means and effects for solving the problem] The present inventor has conducted intensive research in order to achieve the above-mentioned object and to obtain particles with particularly excellent particle properties and an excellent low-energy surface possessed by perfluoroalkyl groups. As a result, methyltrialkoxysilane or its partially hydrolyzed fasteners were treated with ammonia,
It is hydrolyzed in an alkaline aqueous solution of amines or alkali metal hydroxides to form true spherical cores of polymethylsilsesquioxane fine particles, and the perfluoroalkyl trialkoxy immediately remains in a state where the surface activity remains. It was discovered that by adding silane and performing hydrolytic condensation, a surface layer consisting of perfluoroalkylsilsesquioxane units chemically bonded to the core was formed, and the fine particles obtained in this way were The core part consists of polymethylsilsesquioxane units, and the surface part consists of perfluoroalkylsilsesquioxane units, and as mentioned above, the core part and the surface part are chemically bonded, so the surface part It is difficult for the fluoroalkylsilyl group to fall off from the core, so the properties of the perfluoroalkylsilsesquioxane in the surface layer are effectively exhibited, and it has excellent low-energy surface performance, water repellency, oil repellency, lubricity, It was discovered that it has excellent effects in non-adhesiveness, dispersibility, fluidity, etc., and is highly durable, which led to the creation of the present invention.

Therefore, the present invention provides polyorganosolsesquioxane fine particles having a core part made of polymethylsilsesquioxane units and a surface part made of perfluoroalkylsilsesquioxane units, and methyltrialkoxysilane or a portion thereof. After hydrolyzing the hydrolyzed fastener in an alkaline aqueous solution to form a core made of polymethylsilsesquioxane units, perfluoroalkyltrialkoxysilane is added to the aqueous medium in which this core is dispersed and hydrated. Provided is a method for producing polyorganosolsesquioxane fine particles, which comprises performing decomposition and condensation to form a surface layer portion made of perfluoroalkylsilsesquioxane units on the core portion.

The present invention will be explained in more detail below.

As described above, the polyorganosolsesquioxane fine particles of the present invention have a core portion consisting of polymethylsilsesquioxane units (CH, 5i02 units) and a surface layer portion consisting of perfluoroalkylsilsesquioxane units. It is. In this case, the perfluoroalkylsilsesquioxane unit is a R'CH, CH25iO unit (Rf is a perfluoroalkyl group, particularly preferably a perfluoroalkyl group having 4 to 10 carbon atoms). It is preferable that

The polyorganosolsesquioxane fine particles can have a substantially true spherical shape, but of course they can also have an ellipsoidal shape, and the average particle diameter is usually 0.05.
~20 voices.

When obtaining such polyorganosolsesquioxane fine particles, the first step is to form the core of the polymethylsilsesquioxane fine particles. As a method for forming this, known methods for producing polymethylsilsesquioxane fine particles can be adopted, but in particular, a method in which methyltrialkoxysilane or its partially hydrolyzed condensate is hydrolyzed in an aqueous alkaline solution is adopted. be done.

In this case, examples of the raw material methyltrialkoxysilane and its partially hydrolyzed condensates include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, and their partially hydrolyzed condensates. However, it is preferable to use methyltrimethoxysilane or a partially hydrolyzed condensate thereof in terms of availability and production efficiency.

On the other hand, alkali acts as a catalyst for the hydrolytic condensation reaction of alkoxysilyl groups, including monomethylamine, dimethylamine, monoethylamine, diethylamine, monoethanolamine, jetanolamine,
Amines such as ethylenediamine, ammonia and sodium hydroxide.

Examples include alkali metal hydroxides such as potassium hydroxide. The amount of these catalysts should be at least an amount sufficient to neutralize the trace amount of SiCQ or hydrogen chloride remaining in the raw material methyltrialkoxysilane, and since it must be removed eventually, the necessary minimum amount is sufficient. Although it is preferable to use a limited amount, if the amount is too small, gelation tends to occur, and the hydrolytic condensation reaction of the alkoxysilyl group is difficult to proceed, so that the desired product may not be obtained. For this reason, the amount of alkali is appropriately selected from the above points. For example, in the case of ammonia, it is 0.1 to 1
．． 5 mol, and in the case of potassium hydroxide, a range of 0.01 to 0.1 mol is preferable. Also.

The theoretical amount of water in the alkaline aqueous solution is 2 moles of water per mole of alkoxysilyl groups in the raw material methyltrialkoxysilanes, but the alcohol produced by the hydrolysis reaction inhibits the hydrolytic condensation reaction of the alkoxysilyl groups. Therefore, it is usually preferable to use a large excess of water within a range that does not adversely affect subsequent steps.

The hydrolysis and condensation reactions for forming the core of polymethylsilsesquioxane fine particles are carried out by adding methyltrialkoxysilane or a partially hydrolyzed condensate thereof dropwise to the above aqueous alkali solution under stirring, followed by an aging reaction under stirring. It is preferable to achieve this by performing the following steps, but in this case, the above-mentioned dropping time is usually 0.5 to 5 hours, particularly 1 to 3 hours,
The aging time after dropping is usually 0.5 to 3 hours, especially 1 to 3 hours.
It is 2 hours. Further, the reaction temperature, especially the temperature during ripening, is preferably -10 to 50°C, more preferably 0 to 30°C. If the ripening time is too long or the temperature during ripening is too high, the active silanol groups will disappear from the surface of the core part of the fine particles of the obtained polymethylsilsesquioxane, and in the second step There are cases where the surface layer to be formed cannot chemically bond with the core.

Next, in the present invention, after the fine particle core of polymethylsilsesquioxane is formed as described above in the first step, the hydrolytic condensation reaction of perfluoroalkyltrialkoxysilane is performed in the second step. A surface layer of perfluoroalkylsilsesquioxane is formed on the surface of the fine particle core.

In this case, the formation of this surface layer requires a strong bond between the fine particle core and the surface layer through siloxane bonds, so that the active silanol groups on the surface of the fine particle core disappear. It is necessary to carry out a second stage reaction. Therefore, in the second stage of the surface layer formation reaction, the perfluoroalkyltrialkoxysilane is added to the aqueous alkali dispersion of polymethylsilsesquioxane in the state of fine particle nuclei, with active silanol present on the surface, under stirring. It is preferable to add the mixture dropwise to cause a hydrolytic condensation reaction.

The perfluoroalkyltrialkoxysilane used is R'CH2CH25i(OR)3 (in the formula, R/ represents a perfluoroalkyl group and R represents an alkyl group, and in particular Rf represents a perfluoroalkyl group having 4 to 10 carbon atoms. (R is preferably a methyl group or an ethyl group.) are effectively used. Such perfluoroalkyltrialkoxysilanes include CF3CF2CF2CF2
C2H45i(OCH,).

CF3CF2CF2CF2C2H,5i(OC2H5)
31CF3 CF2 CF2 CF2 CF2 CF2
C2H4S l(OCH3)31CF3CF2CF2
CF2CF2CF2C2H4Si (OC2H9) 3°C
F=CF 2CF 2CF 2CF 2CF 2CF
2CF 2CzH4S i(OCH3)3゜CF3CF
2CF2CF2CF2CF2CF2CF2C2H45i
(○C2H,).

CF, CF2CF2CF2CF2CF2CF2CF2C
F2CF2C2H4Si (ocH3)3 TCF3
CF2 CF2 CF2 CF2 CF2 CF2 C
F2 CF2 CF2 C2"4 Sl("2 Hs
) i + etc. are exemplified.

The amount of perfluoroalkyltrialkoxysilane used is
CH, Si of each material varies depending on the use of the final target product.
O! The weight ratio of perfluoroalkylsilsesquioxane units to units is preferably in the range of 3:1 to 50:1; if the ratio exceeds this, the strength of the obtained particles may become weak; If the ratio is smaller, the low energy performance of the perfluoroalkyl group may not be sufficiently exhibited.

When perfluoroalkyltrialkoxysilane is added dropwise to an alkaline aqueous dispersion of polymethylsilsesquioxane, perfluoroalkyltrialkoxysilane may be added dropwise as is, but for the purpose of achieving more uniformity, It is preferred that perfluoroalkyltrialkoxysilane is dissolved in a solvent that dissolves in both fluoroalkyltrialkoxysilane and water, and then added dropwise. Examples of such solvents include methanol, ethanol, isopropanol, acetone, and methyl ethyl ketone.

The dropping time of the perfluoroalkyltrialkoxysilane is usually 5 minutes to 5 hours, especially 15 minutes to 3 hours, and the dropping temperature can be -10 to 50°C, especially 0 to 30°C. After that, the desired product can be obtained by stirring for 5 to 10 hours, but in order to obtain high-performance particles with lower energy, it is preferable to complete the hydrolysis-condensation reaction as much as possible. After dripping 7
Preferably, heating is carried out at a temperature range of 0 to 100°C for 1 to 10 hours. Furthermore, it is effective in completing the reaction to remove the by-product alcohols or the diluting solvent during the perfluoroalkyltrialkoxysilane dropwise addition from the system during the heating and aging step.

When the reaction is carried out as described above, as the reaction progresses, the generated polyorganosolsesquioxane fine particles precipitate from the reaction solution and float on the surface, so they are collected and washed with water. However, if necessary, the target polyorganosolsesquioxane fine particles can be obtained by washing with an organic solvent such as methanol, ethanol, acetone, etc. and drying. In this case, the surfaces of these fine particles are covered with perfluoroalkyl groups, so they have almost no agglomeration, and therefore primary particles with little aggregation can be obtained even in the step after drying, but if necessary, Crushing can also be carried out using a jet mill or the like.

〔Effect of the invention〕

As explained above, according to the method of the present invention, a polyorganosolsesquioxane having a double structure of a core part made of methylpolysilsesquioxane units and a surface part made of perfluoroalkylsilsesquioxane units Fine particles can be obtained efficiently with simple operations, and the core and surface layer of these fine particles are strongly bonded by chemical bonds.

The surface layer is prevented from falling off, and it has excellent durability and can withstand extraction conditions due to dyeing with organic substances or abrasion conditions due to contact with solid substances.

In addition, since the particles have a low energy surface, they have excellent water repellency, oil repellency, lubricity, non-adhesiveness, dispersibility, and fluidity.

Therefore, the polyorganosolsesquioxane fine particles of the present invention can be used as a non-adhesive coating agent (specifically, a coating agent for heat-sensitive recording films, a backing agent for magnetic tape, etc.) in combination with a water/oil repellent agent or a binder resin. It is useful as a coating agent, an anti-staining paint, an anti-sticking paint, a paper coating agent, a car coating agent, etc.), a cosmetic material, a polishing agent additive, a negatively charged toner additive for electrophotography, etc. be.

EXAMPLES Hereinafter, the present invention will be specifically explained by showing examples and comparative examples, but the present invention is not limited to the following examples.

[Example 1] 550 g of water and 50 g of 28% ammonia water were placed in a glass IQ reactor equipped with a stirring blade, a thermometer, a dropping funnel, and a reflux condenser, and the temperature was maintained while stirring at a rotation speed of 150 rpm. was maintained at 20°C. To this, 136 g of methyltrimethoxysilane was added dropwise through a dropping funnel over a period of 1.5 hours, and the mixture was further aged for 1 hour to obtain fine particles of polymethylsilsesquioxane. Next, 28.4 g of CF, (CF2), CH2CH2Si(O
A mixture of CH3) and 40 g of methanol was added dropwise through the dropping funnel over 30 minutes, and the mixture was further aged for 1 hour. During this period, the number of revolutions was 150 rpm, and the temperature was 20
It was kept at ℃. Next, while maintaining the stirring rotation speed at 150 rpm, heating was carried out using an oil bath, methanol was distilled off through an ester adapter until the internal temperature reached 90°C, and an aging reaction was further carried out at 90°C for 3 hours. The generated fine particles were separated floating on the upper layer of the aqueous solution, so they were collected, washed three times with ion-exchanged water, twice with methanol, and finally once with acetone, and air-dried to form white fine particles 86. ．．
4g was obtained.

When these fine particles were observed under an electron microscope, it was confirmed that most of the particles were independent and spherical. In addition, 1 particle size measuring device (Coulter Electron
Coulter Counter manufactured by ics INC.
When the particle size distribution was examined using Model TA-n), the average particle size was 2.1 μs. Further, FTIR analysis confirmed that the surface layer was a perfluoroalkylsilyl group.

These fine particles were formed into tablets using a tablet molding machine for preparing infrared absorption spectrum samples, and when a droplet of ion-exchanged water was placed on the surface of the particles and the contact angle was measured, a value of 148° was obtained. Also, 15g of oleic acid in a 25mQ transparent glass bottle.
When 1 g of fine particles were added, shaken vigorously, and left to stand, the fine particles completely phase separated from the oleic acid and floated on the upper layer of oleic acid, indicating that these particles exhibited excellent oil repellency. confirmed.

[Examples 2 to 4] Using the raw materials shown in Table 1 and using the same method as in Example 1, a polyorganoid having a core portion of polymethylsilsesquioxane and a surface layer of perfluoroalkylsilsesquioxane was prepared. Solsesquioxane fine particles were obtained.

Further, the contact angle with water and the wettability with oleic acid of the obtained fine particles were measured in the same manner as in Example 1.

The results are shown in Table-2.

[Comparative example]

CF, (CF, ), CH2CH25i (○CH,
).

A mixture of 30 g of methanol and 30 g of methanol was added dropwise thereto, and methanol was removed by heating to 90° C. with stirring to obtain perfluoroalkylsilane-treated fine particles.

The contact angle with water and the wettability with oleic acid were examined in the same manner as in Example 1 for the obtained fine particles and the fine particles obtained by washing them with acetone and drying them. The results are shown in Table-2.

Claims (1)

[Scope of Claims] 1. Polyorganosolsesquioxane fine particles having a core portion consisting of polymethylsilsesquioxane units and a surface layer portion consisting of perfluoroalkylsilsesquioxane units. 2. After hydrolyzing methyltrialkoxysilane or its partially hydrolyzed condensate in an alkaline aqueous solution to form a core consisting of polymethylsilsesquioxane units,
The method is characterized in that a perfluoroalkyltrialkoxysilane is added to an aqueous medium in which the core is dispersed, and hydrolytic condensation is carried out to form a surface layer composed of perfluoroalkylsilsesquioxane units on the core. A method for producing polyorganosolsesquioxane fine particles.