JP3408604B2 - Manufacturing method of inorganic / organic coating - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inorganic material having excellent heat resistance, hardness and adhesiveness, as well as excellent corrosion resistance, flexibility, slidability and water repellency.
The present invention relates to a method for forming a coating film having an organic hybrid structure . [0002] In order to obtain a high degree of heat resistance, abrasion resistance and corrosion resistance, organic coatings are not sufficient, and ceramic coatings are used. Conventionally, as a method of forming a ceramic coating, PVD (sputtering method, etc.),
CVD, sol-gel methods, polytitanocarbosilane-based coatings, poly (disil) silazane-based coatings, polysilazane-based coatings, polymetallosilazane-based coatings, and the like are known. On the other hand, various organic paints are known which use a fluororesin and add various fillers as necessary in order to obtain corrosion resistance, flexibility, slidability and water repellency. further,
A heat-resistant paint containing a ceramic precursor resin composed of a silicon compound such as a polycarbosilane resin, a polysilazane resin, or a polyborosiloxane resin, a fluororesin, and an inorganic filler has also been proposed (JP-A-4-16817).
Nos. 5 and 5-156176). [0004] Ceramic coatings are excellent in heat resistance, hardness, adhesion and the like, but are insufficient in flexibility, slidability and water repellency. On the other hand, fluororesin-based coatings are excellent in flexibility, slidability, water repellency and the like, and the hardness is improved by adding an inorganic filler, but the heat resistance, adhesion and the like are insufficient. [0005] Further, since the above-mentioned heat-resistant paints containing a ceramic precursor resin and a fluororesin each use a silicon compound containing an organic group, the effects on heat resistance, hardness and adhesion are not yet sufficient. In particular, since pinholes and cracks accompanying shrinkage occur due to the elimination of organic groups during baking, a sufficiently dense film cannot be obtained, and the adhesion to the substrate is also insufficient. Further, in the heat-resistant paint, it is essential to add an inorganic filler or glass fiber or the like, and although these can improve the hardness, they do not contribute to the adhesiveness at all. The properties and flexibility are reduced. The present invention solves these problems and is excellent in flexibility, slidability, water repellency as well as heat resistance, hardness and adhesion, and also excellent in corrosion resistance, electric insulation, stain resistance and the like. Was
An object of the present invention is to provide a method for producing a coating film having an inorganic / organic hybrid structure . [0007] In order to achieve the above object, the present invention mainly provides a compound represented by the following general formula (I): A coating liquid mainly composed of perhydropolysilazane having a number average molecular weight of 100 to 50,000 having a main skeleton composed of units represented by the following formula : Fluororesin powder having a particle diameter of 1 μm or less A method for producing an inorganic / organic coating, comprising applying a coating composition to which a coating is added to a substrate, followed by baking at 300 ° C. or more in air. The polysilazane used is an inorganic polysilazane (perhydropolysilazane) [for example, Japanese Examined Patent Publication No. 63-1).
6325, JP-A-1-138108, 1-138
No. 107, 4-63833, Japanese Patent Application No. 3-32016
No. 7] is preferred. The polysilazane to be used includes a polysilazane having a chain, cyclic or cross-linked structure, or a polysilazane having a plurality of these structures in a molecule at the same time. These polysilazanes can be used alone or as a mixture. Typical examples of the polysilazane used include the following, but are not limited thereto. The method for producing perhydropolysilazane is, for example,
It is reported in JP-B-63-16325. What is obtained by these methods is a mixture of polymers having various structures, but basically contains a chain portion and a cyclic portion in the molecule. Can be represented by the following chemical formula: An example of the structure of perhydropolysilazane is as follows. Embedded image [0016] [0017] [0018] [0019] [0020] [0021] [0022] [0023] [0024] [0025] [0026] When the perhydro polysilazane is mixed with the fluorine resin particles, perhydro polysilazanes usually solvent Allow to dissolve. Examples of the solvent include aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbon solvents, halogenated hydrocarbons such as halogenated methane, halogenated ethane, and halogenated benzene, aliphatic ethers, alicyclic ethers. And the like. Preferred solvents are methylene chloride, chloroform, carbon tetrachloride, bromoform, ethylene chloride, halogenated hydrocarbons such as ethylidene chloride, trichloroethane, tetrachloroethane, ethyl ether, isopropyl ether, ethyl butyl ether, butyl ether, 1,2-dioxyethane, dioxane ,
Ethers such as dimethyldioxane, tetrahydrofuran, tetrahydropyran, etc .; Hydrogen and the like. When these solvents are used, two or more solvents may be mixed in order to adjust the solubility of the fluororesin-added perhydropolysilazane and the evaporation rate of the solvent. The amount of solvent (ratio), as better workability by coating methods employing, also selected by the film thickness to be required and the average molecular weight of perhydro polysilazanes, molecular weight distribution, it is different depending on the structure, the coating composition The medium solvent can be mixed up to about 95% by weight, and preferably the solid content can be mixed in the range of 5 to 60% by weight. As the fluororesin to be used, various fluororesins can be used, but from the viewpoint of heat resistance, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PF)
A), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-hexafluoropropylene-perfluoroalkylvinyl ether copolymer (EPE), tetrafluoroethylene-ethylene copolymer (ETFE), polychloro Preferred are trifluoroethylene (PCTFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF) and the like. Particularly, PTFE is preferred. However, PTFE hardly melts even at a temperature higher than its melting point, so that the film strength alone cannot be obtained (resin properties cannot be obtained). Therefore, PFA or F
It is better to use a melting fluororesin such as EP in combination with PTFE. The size of the fluororesin particles is 1 μm or less.
However, if possible, about 0.3 μm is desirable . This is because it is advantageous to hybridize uniformly and finely. The fluororesin particles are preferably made into a dispersion and mixed with the perhydropolysilazane solution, but the dispersion medium is preferably the same as the solvent used in the perhydropolysilazane solution. Usually, xylene, toluene and the like. At this time, a commercially available dispersion can be used. For example, KD200AS (a PTFE xylene dispersion having a particle size of 0.3 μm, solid content: 30 wt%) manufactured by Kitamura Corporation. When powder is used, it is better to prepare the above-mentioned dispersion liquid in advance. At this time, a commercially available dispersant should be used. The mechanical mixing and stirring can be performed according to the pigment dispersion method. [0030] When creating a coating solution containing a perhydro polysilazane and fluororesin particles, in general
A dispersion of perhydro polysilazane solution and the fluororesin particles may be mixed. The amount of perhydro polysilazane and fluorine resin particles, can be selected widely depending on the coating application, for example, when importance is attached flexibility is total solids [total amount of perhydro polysilazane fluororesin]
As the 100 wt%, 5 to the perhydro polysilazane
The range is 30% by weight, and when importance is placed on hardness and heat resistance, the range is preferably 30 to 90% by weight. [The amount of the fluorine resin is the amount excluding the amount of perhydro polysilazanes of the solid content. In the present invention, though not essential, a suitable filler may be added as needed. Examples of the filler include fine powders of oxide-based inorganic substances such as silica, alumina, zirconia, and mica, and non-oxide-based inorganic substances such as silicon carbide and silicon nitride. Depending on the application, metal powder such as aluminum, zinc, and copper can be added. Further examples of fillers include silica silica, quartz, novacurite, diatomaceous earth, and other silica-based materials: synthetic amorphous silica: kaolinite, mica, talc, wollastonite, asbestos, calcium silicate, aluminum silicate Glass bodies such as glass powder, glass spheres, hollow glass spheres, glass flakes, foam glass spheres: boron nitride, boron carbide, aluminum nitride, aluminum carbide, silicon nitride, silicon carbide, titanium boride, nitride Non-oxide inorganic substances such as titanium and titanium carbide: calcium carbonate: metal oxides such as zinc oxide, alumina, magnesia, titanium oxide, beryllium oxide: barium sulfate, molybdenum disulfide, tungsten disulfide, carbon fluoride and other inorganic substances: Metal powders such as aluminum, bronze, lead, stainless steel, zinc, etc .: carb Black, coke, graphite, pyrolytic carbon, carbon and the like of the hollow carbon spheres and the like. These fillers can be used alone or in various shapes such as needles (including whiskers), granules, and scales.
A mixture of more than one species can be used. Further, it is desirable that the particle size of these fillers is smaller than the film thickness that can be applied at one time. The addition amount of the filler fluorine resin and peroxide
The total 1 part by weight of perhydropolysilazane ranges from 0.05 to 10 parts by weight, particularly preferred amount is in the range of 3 weight parts 0.2 parts by weight. Further, the surface of the filler may be surface-treated by coupling agent treatment, vapor deposition, plating or the like before use. The coating composition may contain various pigments, leveling agents, defoamers, antistatic agents, ultraviolet absorbers, pH adjusters, dispersants, surface modifiers, plasticizers, drying accelerators, if necessary. An anti-flow agent may be added. The coating composition of the present invention thus prepared is repeatedly applied once or twice or more on a substrate, and then baked to form a coating film. The substrate on which the coating composition is applied is not particularly limited, and may be any of metals, ceramics, plastics and the like. As a coating means as a coating, a usual coating method, that is, dipping, spin coating, roll coating, bar coating, brush coating, spray coating, flow coating or the like is used. Also, sand the base before applying,
If surface treatment is performed by degreasing, various blasts, etc., the adhesion performance of the coating composition is improved. After coating by such a method and sufficiently drying, heating and baking are performed. By this firing, the polysilazane is crosslinked, condensed, or oxidized, hydrolyzed and hardened depending on the firing atmosphere to form a ceramic coating. At the same time, the fluororesin particles are melted to form Si—O bonds or Si—N bonds. It is possible to obtain a dense film in which a ceramic portion as a main component and an organic portion made of a fluororesin are composited at a fine structure level (compared with a composite material to which an inorganic filler or the like is added). The firing temperature is equal to or higher than the melting point of the fluororesin, and
It is preferred perhydro polysilazane is a temperature sufficiently ceramization. This is usually 300 ° C. or higher, preferably about 400 ° C. The firing conditions vary depending on the molecular weight and structure of perhydro port <br/> Rishirazan. The heating rate is not particularly limited, but a gradual heating rate of 0.5 to 10 ° C./min is preferable. The present invention uses air as the firing atmosphere. Oxidation of perhydropolysilazane or hydrolysis by water vapor coexisting in the air proceeds by baking in the air. [0036] As mentioned above, the combination of perhydro Po <br/> Rishirazan fluororesin accordance with the present invention, hybrid inorganic / organic coating with a fine structure level is obtained. In particular, inorganic polysilazane (perhydropolysilazane) is particularly excellent in heat resistance, hardness, and adhesion, and a combination with a fluororesin, which is characterized by elongation, is a well-balanced composite system that compensates for each other's disadvantages. Provides properties that surpass composite coatings. When a combination of perhydropolysilazane and fluororesin is used, this is different from a so-called composite resin in which a glass filler or the like is added, and the perhydropolysilazane dissolved in xylene uniformly surrounds the fine fluororesin filler. Since the starting state is a state of morphology, it is expected that amorphous SiO ₂ / Si ₃ N ₄ and a fluororesin are compounded at a very homogeneous and fine structure level, and that the perhydropolysilazane is made into a ceramic. This is considered to be because the fluororesin softens and follows the shrinkage due to the shrinkage, so that a dense film without pinholes is easily obtained. Further, according to the present invention, it is easy to control the balance between an inorganic substance (ceramics) and an organic substance (fluororesin). As described above, since the ceramics and fluororesin-based perhydro polysilazane is complexed with a uniform and fine structure level, the ratio of the inorganic and organic can be selected from a wide ratio range, heat resistance, those had emphasis on the hardness Excellent characteristics can be realized in a wide range up to those emphasizing flexibility. Further, since perhydropolysilazane becomes an amorphous ceramic having a low coefficient of thermal expansion after firing, the film thickness limit is low alone due to the problem of matching with a metal substrate or the like, but fluororesin has a high coefficient of thermal expansion. Matching with various substrates is possible, and therefore, a thick film having a thickness of 10 to 100 μm can be easily applied to the coating composition of the present invention. Incidentally, summarized by comparing amorphous ceramic and characteristics of the fluororesin after firing of perhydro polysilazane is as follows. [0040] perhydro polysilazanes (amorphous ceramic after firing) fluororesin ───────────────────────────── hardness higher low elongation very low Extremely high heat resistance Extremely high Relatively high coefficient of thermal expansion Extremely low High adhesion Very high Bad sliding property-Extremely good Water repellency-Extremely good Ceramic yield Extremely high-Shrinkage ratio Relatively low-Thermal properties Thermosetting Heat softening, Example 1 (Case with emphasis on flexibility) The following raw materials were used. Tonen perhydropolysilazane (PHPS-1, M
30% by weight xylene solution (n ≒ 800, structure of Chemical formula 3). PTFE dispersion KD200AS manufactured by Kitamura Co., Ltd. (particle size: 0.3 μm, 30 wt% xylene solution). Asahi Glass Co., Ltd. PFA powder TW-3507 (particle diameter 7 μm). Asahi Glass Co., Ltd. resin surface modifier S-381 (70wt
% Ethyl acetate solution). First, a PFA xylene dispersion having a solid content of 30 wt% is prepared. At this time, for 100 wt% of the dispersion,
The S-381 solution is added to xylene in advance so that the addition amount of the S-381 solution becomes 3 wt%, and the mixture is stirred. PFA powder is added to this xylene solution, and a PFA xylene dispersion is prepared by using a vibration mill. next,
,, And the ratio of PHPS / PTFE / PFA is 1
5:35:50 were mixed so that (wt%), Peruhido
B and polysilazane / fluororesin-based coating solution of (solid content 30 wt% xylene solution). This coating solution was degreased 150 ×
Each substrate of 50 × 0.4 ^t _{mm made} of stainless steel (SUS304), aluminum (A5052) and copper (C1100) was applied by flowing coating, and dried at room temperature for 10 minutes. Fifteen
After prebaking at 0 ° C for 10 minutes to sufficiently evaporate the solvent, baking at 400 ° C for 1 hour (heating at 10 ° C / minute),
An inorganic / organic hybrid coating film was used. The thickness was about 10 μm. The obtained film was translucent, adhered firmly to each substrate, and no defects such as cracks were observed under a microscope. Particularly, for a copper substrate, 400 ° C.
It was found that the oxidation of copper was prevented and that the coating was a heat-resistant coating excellent in denseness and adhesion (copper was easily oxidized and an oxide film was easily peeled off). Next, the coating film hardness, flexibility (flexibility) and adhesion were evaluated according to JIS-K-6894. The results are summarized in Table 1. Table 1, composed of only a fluororesin containing no perhydro polysilazane (PTFE: PFA =
35:50) A similar coating was shown as Comparative Example 1. [Table 1] According to this, as in Comparative Example 1, a coating film made of only a fluororesin is soft and has poor adhesion.
In contrast to the inherent disadvantages of fluororesins, Example 1 revealed that a coating film having practical flexibility and excellent flexibility and adhesion was formed. Example 2 (with emphasis on heat resistance) Using the same raw materials as in Example 1,
When the ratio of PS / PTFE / PFA is 50:40:10 (wt.
And so that%), to prepare perhydro polysilazane / fluororesin-based coating solution (solid content 30 wt% xylene solution), and construction to each substrate under the same welding conditions, 10 [mu]
m of inorganic / organic hybrid membrane was obtained. The resulting membrane is
It was translucent, firmly adhered to each substrate, and no defects such as cracks were observed under a microscope. In particular, the luster of the copper was maintained in the copper substrate. Next, according to JIS-K-6894, the hardness, adhesion and heat resistance of the coating film were evaluated. The results are summarized in Table 2. Note that Table 2 shows commercially available organic silazane NC manufactured by Nissan.
Using P-200 (Mn ≒ 1200), the result of evaluation of a coating film obtained in exactly the same manner as in Example 2 is shown as Comparative Example 2. [Table 2] According to the present invention, an inorganic / organic hybrid having excellent heat resistance, hardness, adhesion, flexibility, corrosion resistance, slidability, water repellency, stain resistance, and electrical insulation. A membrane can be easily obtained.

Continuation of front page (56) References JP-A-5-156176 (JP, A) JP-A-4-168175 (JP, A) JP-A-1-138108 (JP, A) JP-A-3-32618 (JP) JP-A-62-156135 (JP, A) JP-A-2-175726 (JP, A) JP-A-4-102412 (JP, A) JP-A-4-100877 (JP, A) 63-16325 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 183/16 C09D 127/12-127/20 C08L 83/16 C08L 27/12-27/20 C01B 21 / 082 C01B 21/087 C08G 77/62

Claims (1)

(57) [Claims] [Claim 1] Mainly, general formula (I): A coating composition obtained by adding a fluororesin powder having a particle diameter of 1 μm or less to a coating liquid containing perhydropolysilazane as a main component having a number average molecular weight of 100 to 50,000 having a main skeleton composed of units represented by the following formula: After that, it is baked at 300 ° C. or more in air.
Manufacturing method of organic coating.