KR960011840B1 - Coating composition - Google Patents

Abstract

The composition comprises 35-47 wt.% complex binder solvent, 16-20 wt.% heat-resisting pigment, 0.5-2.5 wt% modified catalyst and 10-12 wt.% incohesive additive. The complex binder is prepared by reacting an inorganic binder and an organic binder in a ratio of 0.5:1 to 1:0.5. The inorganic binder is prepared by reacting colloidal silica and silane coupling agent, and the organic binder is polytitanocarbosilane or silicon banish. The coating composition is used for electrical oven, microwave oven, kitchen utensils and in-outdoor lamp requiring an incohesion, heat-resistance and corrosive-resistance.

Description

Coating composition

The present invention relates to a coating composition for forming a coating film excellent in heat resistance, non-adhesiveness and corrosion resistance which is treated where non-adhesiveness and heat resistance such as an electric oven, microwave oven, kitchen support and the like are required.

Conventional non-adhesive heat resistant paints are known as silicone heat resistant paints and Teflon paints. Silicone heat resistant paints have limited heat resistance of about 300-350 ° C. due to the nature of silicone resins, resulting in high heat resistance, adhesion and corrosion resistance. Unexpectedly, the Teflon-based paint having excellent non-adhesive property was limited to a stable use temperature of 300 ° C. or lower, and thus non-adhesiveness at high temperature could not be expected.

According to Japanese Patent JK 57-209962, in order to compensate for the defects of the aforementioned Teflon coating and the enamel coating, which is excellent in heat resistance and non-adhesiveness, 7 parts of alpha-alumina or silica as a layer agent is added to 80 parts of aqueous sodium silicate solution. It is known to prepare an inorganic paint by mixing and adding 15 parts of zinc oxide, monobasic phosphate as a curing agent, and then adding the same amount to 2 times the amount of Teflon paint (ethylene tetrachloride).

In addition, the above-mentioned patent document treats the prepared inorganic heat-resistant paint on the surface of the substrate so as to have a coating film thickness of 30-50 μm, and then dried at 400 ° C., the inorganic heat-resistant paint sinks underneath and acts as a bottom coat, and Teflon floats up to form an inorganic paint. It is said that it can make use of heat resistance and non-tackiness of Tef paint.

However, the aforementioned patent uses organic tetrafluoroethylene resin coating material, so even if the inorganic heat-resistant paint acts as a bottom underneath, the heat resistance will be up to 400 ° C or less, so that heat resistance, corrosion resistance and non-adhesiveness at high temperatures can be expected. There is no.

SUMMARY OF THE INVENTION An object of the present invention is to provide a coating composition which solves the problems shown in the enamel coating film and the Teflon coating film described above and forms a stable coating film even at a high temperature of 400 ° C or higher.

According to the present invention, a coating composition comprising an inorganic binder having a siloxane structure and an organic-inorganic composite binder composed of an organic binder as a main component and a solvent, a heat-resistant pigment, a modified catalyst, a heat-resistant catalyst, and a non-tacky additive as other components is described above. The object of the invention is achieved.

One embodiment of the present invention is 35-47% by weight of an inorganic-inorganic composite binder prepared by combining an inorganic binder having a siloxane structure and an organic binder prepared by reacting colloidal silica with a coupling agent in a weight ratio of 0.5: 1 to 1: 0.5, It consists of a film composition which consists of 20-36 weight% of solvents, 16-20 weight% of heat-resistant pigments, 0.5-2.5 weight% of a modified catalyst, and 10-12 weight% of non-adhesive additives for heat-resistant reinforcement.

In the coating composition of the present invention, the inorganic binder having a siloxane structure is mixed with colloidal silica in a weight ratio of 3: 1-1: 2 with a silane coupling agent in the presence of an organic solvent such as an alcohol solvent or an aromatic hydrocarbon solvent. It is made by reaction. The colloidal silica used at this time is advantageous to obtain more excellent heat resistance and coating film stability using acidic colloidal silica having a SiO ₂ content of 20-30%.

As a silane coupling agent used for preparation of an inorganic binder, it selects from methyltrimethoxysilane, tetraethoxysilane, and methyltriethoxysilane which form a silanol compound easily. When the colloidal silica and the silane coupling agent are synthesized at room temperature, an exothermic reaction occurs, followed by continuous hydrolysis and dehydration condensation reactions, and water and methanol are produced to obtain an inorganic binder having a siloxane structure. The solvent is mixed to obtain an inorganic binder mixture.

The inorganic binder mixture thus prepared can be used as a suitable inorganic binder for heat and corrosion resistant paints.

In the present invention, the organic binder is blended to impart flexibility, flexibility, and corrosion resistance to the above-described inorganic binder. As the organic binder, pure silicon varnish (SiO ₂ content: 50-60%) or varnish of poly titano carbosilane ( Hometown content: 40-50%).

The organic binder and the inorganic binder are blended in a weight ratio of 0.5: 1-1: 0.5, and reacted at room temperature in the presence of a silane coupling agent and an organic titanate-based catalyst to obtain an organic-inorganic complex binder used in the present invention.

When the mixing ratio of the organic binder and the inorganic binder is out of the above range and the inorganic binder is large, the flexibility and the corrosion resistance are decreased, and when the organic binder is large, the heat resistance and the wear resistance are reduced.

The organic-inorganic composite binder described above is included 35-47% based on the total weight of the coating composition of the present invention, the heat resistance is lowered at 35% or less, and the adhesion is lowered at 47% or more.

The composition of the present invention contains 20-30% of an alcohol or an aromatic solvent as a solvent in order to facilitate the mixing and viscosity control of the inorganic binder and the organic binder described above. As the alcohol solvent used in the present invention, methanol, ethanol, isopropanol, and the like are used. As the aromatic solvent, xylene, toluene, butyl cellosolve, etc. are used, and these solvents may be used in a mixture state.

In addition, the composition of the present invention includes a catalyst for promoting the reaction to bond the inorganic binder and the organic binder at room temperature, such a catalyst comprises a 0.5 to 2.5% by weight of a titanate-based catalyst and a silane coupling agent. When the titanate-based catalyst and silane coupling agent were used, the adhesion and impact properties were poor when the amount thereof was 0.5% or less, and the flexural properties were poor when the amount was 2.5% or more. The range of 0.5-2.5 wt% showed the best physical properties. .

Tetrabutyl titanate or tetraisopropyl titanate is used as a tinate catalyst, and gamma methacryloxy propyl trimethoxysilane or gamma glycidoxy propyl ethoxysilane is used as a silane coupling agent.

As other additives used in the composition of the present invention, 16-20% by weight of inorganic pigment black pigment and low melting point glass frit, a heat-resistant reinforcing agent, and 10-12% by weight of a non-stick filler or anti-settling agent for imparting adhesion do.

Since the reaction which occurs when preparing the coating composition of the present invention described above occurs at room temperature, the organic-inorganic composite binder is prepared by mixing all the components at the same time.

The coating composition of the present invention described above is treated in a substrate by a conventional coating method such as spray coating, the solvent is volatilized and dried at 350 ° C.-370 ° C. to form a high temperature heat resistant coating film.

According to the present invention described above, since the organic-inorganic composite binder is not only excellent in heat resistance, but also excellent in adhesion to the base, when the base is treated, it forms a stable coating film even at 400 ° C or higher.

Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1-4

Preparation of Film Composition

In preparing the coating composition, the components described in each Example in Table 1 were used according to the amount of use thereof. The colloidal silica is mixed with a coupling agent in the presence of an alcoholic solvent and an aromatic solvent, and the resultant mixture is reacted at room temperature by adding an organic binder, a catalyst and a silane coupling agent, and then a reaction product such as a pigment, a non-tacky filler, and a glass frit. The additives are mixed to obtain a liquid coating composition.

Test Example

The coating composition prepared in Example was subjected to air spray coating so that the thickness of the coating film was 30 ± 5 μm on a 6 cm × 15 cm × 0.5 T stainless steel specimen which had been degreased, followed by volatilization of a solvent on the coating film for 20 minutes at 370 ° C. The physical properties of the next coating film were measured.

The physical properties of the measured coating film are shown in Table 2.

① PTFE: Polytetrafluoroethylene

② Silane coupling agent: gamma methacryloxypropyl trimethoxysilane

(Note) Adhesion 1) After drying at 370 ° C. for 20 minutes, the coating film was cross-cut by 1 mm × 1 mm and then tested using (cellophane tape).

2) The same adhesion test was carried out after holding at 550 × 8 hours.

Heat resistance 1) Measured by repeating the process of water-cooling after maintaining for 1 hour in an oven at 450 ℃.

2) Repeatedly measured three times the process of water cooling after holding for 1 hour in an oven at 550 ℃.

Non-tackiness 1) Test by dropping chicken oil and cooking oil drops after drying at 370 ℃ × 20 minutes.

2) After keeping at 550 ℃ for 1 hour, drop the chicken oil and cooking oil drop and test.

Corrosion resistance 1) 240 hours of saline spraying after drying at 370 ° C for 20 minutes.

2) Tested with salt spray for 240 hours after holding at 550 ° C for 8 hours.

Claims (4)

Organic-inorganic composite binder prepared by reacting an inorganic binder having a siloxane structure prepared by reacting colloidal silica with a silane coupling agent and an organic binder selected from polytitano carbosilane and silicone varnish at a weight ratio of 0.5: 1 to 1: 0.5 Heat-resistant film composition comprising -47% by weight, solvent 20-36% by weight, heat-resistant pigment 16-20% by weight, modified catalyst 0.5-2.5% by weight, heat-resistant reinforcing non-adhesive additive 10-12% by weight. The coating composition according to claim 1, wherein the colloidal silica is acidic colloidal silica having a solid content of 20-30% by weight and the silane coupling agent is selected from methyltrimethoxysilane, tetraethoxysilane and methyltriethoxysilane. . The coating composition according to claim 1, wherein the organic-inorganic composite binder is a reaction product produced by a reaction between an organic binder and an inorganic binder having a siloxane structure in the presence of a silane coupling agent and a titanate-based catalyst. The coating composition of claim 1 wherein the organic binder is selected from polytitanocarbosilane and silicone varnish with a solid content of 40-45%.