JPH0369384B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention is an inorganic aqueous slurry composition that has excellent long-term storage stability, controlled thixotropy, and good workability. This invention relates to a binder for inorganic compositions that provides crack-free inorganic coatings with excellent chemical resistance and boiling water resistance. The inorganic composition according to the present invention is used as a coating agent or a filler. [Prior Art] Conventionally, a reaction product of a partially hydrolyzed silane compound and colloidal silica is used as a binder.
Inorganic compositions containing inorganic powders such as silica, alumina, and zirconia are well known, and as silane compounds, they have the following general formula RSi(OR') ₃ (wherein, R is -CH ₃ or

[Purpose of the invention]

The object of the present invention is to improve the above-mentioned drawbacks and provide a new inorganic composition binder that takes advantage of the excellent heat resistance and chemical resistance of these inorganic compositions. [Structure of the Invention] The present invention provides that the above-mentioned silane A or B has the general formula R″ ₂ Si(OR′) ₂ (wherein R′ represents −CH ₃ or −C ₂ H ₅ , and R″ represents _-CH3 ), a silane compound represented by
For example, (CH ₃ ) ₂ Si(OCH ₃ ) ₂ (hereinafter referred to as silane C)
This is based on the discovery that the above-mentioned drawbacks of conventional products can be solved by mixing them in a specific ratio. Here, the disadvantages that occur when Silane C is used alone are: (1) The heat-cured film becomes too soft. (2) Heat curing takes a long time. It has been found that these drawbacks can be solved by using the above-mentioned silane A or B in combination. In the present invention, the mixing ratio of silane A or silane B and silane C is preferably in the range of 9:1 to 1:9 by weight. This is not preferable because it causes defects. [Example] The present invention will be explained in more detail below with reference to Examples. Example 1 A mixture of silane A and silane C (composition ratio shown in Table 1 below) was added to 30 g of pure water in which 3 g of acetic acid was dissolved.
g was added thereto and reacted at room temperature for 5 to 15 minutes to obtain a partially hydrolyzed silane compound. Next, a 250% aqueous solution of colloidal silica (containing 21wt% as SiO ₂ ) was added to this.
g was added and reacted at room temperature for 5 to 30 minutes to obtain an inorganic composition binder. In addition, the average particle size is about 20μ
400g of silica powder, 100g of silica powder of about 10μm
g and 100 g of alumina powder (average particle size of about 5 μm) were added together with 50 g of methanol, and the mixture was allowed to stand for 2 to 4 days to obtain inorganic slurry compositions Nos. 1 to 7. We evaluated the stability of the slurry, the curing speed of the coating film (coating approximately 2 mm thick on a steel plate, drying at room temperature for 12 hours, and curing at 160°C), heat resistance, and appearance observation (presence of cracks, etc.). I went. The results are shown in Table 1. Example 2 Inorganic slurry compositions Nos. 8 to 13 were obtained in the same manner as in Example 1 except that Silane B was used in place of Silane A in Example 1. The stability, curability, and cured coating properties of this slurry were evaluated, and the results are shown in Table 2. As is clear from Examples 1 and 2, the partially hydrolyzed silanes were mixtures of silane A/silane C and silane B/silane C in a weight ratio of 9/9.
By using one having a ratio of 1 to 1/9, an inorganic composition binder with well-balanced properties and an inorganic slurry composition using the same can be obtained. Example 3 An inorganic binder composition that is a reaction product of the hydrolysis product of the silane A/silane B mixture (1/1 weight ratio) used in inorganic slurry composition No. 4 of Example 1 and colloidal silica. When we coated an iron plate with only the material (without powders such as silica and alumina), a transparent, uniform, continuous film was formed. When this is heated at 160℃ for 20 minutes to harden it,
Even when heated to 600℃, the coating did not crack, peel, or discolor, and a coating with excellent heat resistance was obtained. Further, this film did not peel or crack even after being immersed in boiling water for 1 hour, and maintained its water repellency. Moreover, no change occurred even when immersed in organic solvents such as tricrene, alcohol, and gasoline for one week at room temperature, and the material had excellent heat resistance, boiling water resistance, and chemical resistance.

【table】

[Table] Yes, × indicates loss of water repellency.

Claims (1)

[Scope of Claims] 1. In a slurry composition based on water or a mixture of water and lower alcohol, which is made by using a reaction product of a partially hydrolyzed silane compound and colloidal silica as a binder and adding an inorganic powder to this, as a silane compound. The following general formula RSi(OR') ₃ (in the formula, R represents -CH ₃ or [formula], and R' represents -CH ₃ or -C ₂ H ₅ )
and the following general formula R″ ₂ Si(OR′) ₂ (wherein R′ represents −CH ₃ or −C ₂ H ₅ and R″ represents −CH ₃ ). 9 compounds:
An inorganic composition binder characterized in that it is used by mixing at a ratio of 1 to 1:9 (weight ratio).