JPH02247267A - Coating compound composition - Google Patents

Abstract

PURPOSE:To obtain a coating compound composition having excellent heat resistance, corrosion resistance and high calcination residual ratio in air by dispersing and dissolving polycarbosilastyrene and an inorganic filler in an organic solvent. CONSTITUTION:100 pts.wt. polycarbosilastyrene and 10-900 pts.wt., preferably 30-300 pts.wt. inorganic filler (e.g. oxide, borate or phosphate of Mg, Ca, Ba or Ti) are dispersed or dissolved in an organic solvent (e.g. toluene or xylene) to give the aimed composition.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a novel coating composition containing polycarbosilastyrene, and more specifically, contains polycarbosilastyrene and an inorganic filler, and has heat-resistant properties. , relates to a novel coating composition with excellent corrosion resistance.

(Prior Art and its Problems) Paints containing polyorganosiloxane as a vehicle and various pigments added thereto are known as heat-resistant paints for preventing corrosion and deterioration of metal and non-metal substrates at high temperatures. This polyorganosiloxane paint has excellent heat resistance when compared with conventionally known organic polymer paints such as polyester and polyimide, but the paint film still peels off from the base material.

Furthermore, with the development of industry, 100°
There is an increasing demand for coating materials that can prevent oxidation and corrosion of metal or nonmetal substrates exposed to high temperatures exceeding C.

Japanese Patent Publication No. 59-12746 discloses that after coating a metal base material with a polycarbosilane containing carbon and silicon as skeleton components and a small amount of metal elements, 800 to 2
A method is described in which polycarbosilane is converted into silicon carbide by heating and baking at 000°C to form a ceramic coating on a metal substrate. Also, JP-A No. 55-8
No. 4370 discloses that after applying a coating composition in which ceramic or metal powder is added to a semi-inorganic compound containing polycarbosilane to a metal or non-metal substrate, the coating composition is heated to 400 to 2000'C in a non-oxidizing atmosphere. A method for obtaining a heat-resistant film by heating and baking is described.

However, in an oxidizing atmosphere such as air, the firing survival rate of this polycarbosilane at 1000°C is about 30
% (weight equivalent), a large volumetric shrinkage occurs due to thermal decomposition of polycarbosilane during heating and baking. For this reason, the adhesion of the fired film to the base material becomes insufficient. Therefore, when the film is heated and baked in an oxidizing atmosphere such as air, most of the film peels off from the base material. Furthermore, the heat resistance temperature of a partially formed film in air is about 400°C, which is not much different than the heat resistance temperature of a film made of a conventional polyorganosiloxane paint.

(Objective of the Invention) The object of the present invention is to provide a coating composition that has a high firing survival rate in air and is capable of forming a film with a high heat resistance temperature in air. The aim is to effectively prevent oxidation and corrosion of metal or non-metallic base materials.

(Means for Solving the Problems) The present invention provides a coating composition comprising 10 to 900 parts by weight of an inorganic filler dispersed or dissolved in an organic solvent based on 100 parts by weight of polycarbosilastyrene. It is related to.

As the polycarbosilastyrene in the present invention, an organosilicon polymer copolymer is used, which is composed of the carbosilane bond unit shown in (1) below and the silastyrene bond unit shown below (II), and in some cases has partially crosslinked bonds. It will be done.

(However, R1 is -H or -CH, and R2 is -CH.

or -C, H,) (However, R3 and R4 may be the same or different and each independently represent -CH, -C6H, or -H.) The organosilicon polymer copolymer The ratio of the bonding units CI) and (II) in is expressed as a molar ratio of []/(II)=
'7/3 to 3/7, and its average degree of polymerization is 1
000 or more, preferably in the range of 1,500 to 50,000.

The polycarbosilastyrene has the following formula (1) (however,
R3 represents -CH3 or -Cb Hs, and X is 0.3
-0.7, preferably 0.45-0.55, and the degree of polymerization n is in the range 10-3000. ) It can be produced by using polysilastyrene represented by the following as a raw material and subjecting it to heat treatment or ultraviolet treatment.

For example, the raw material polysilastyrene can be prepared by mixing dichlorodimethylsilane and dichloromethylphenylsilane with toluene,
It can be easily synthesized by using sodium metal as a catalyst in an inert solvent such as xylene and reacting at a temperature above its melting point.

Moreover, as polycarbosilastyrene in the present invention,
An organic compound consisting of the carbosilane bond unit of (N), the silastyrene bond unit of (II), and the metalloxane bond unit of (IV), in which at least a portion of the silicon atoms have a bond crosslinked via the metal of the metalloxane bond unit. A silicon polymer copolymer can also be used.

+M−0← −−−−(IV) (However, M represents Ti or Zr, and in some cases,
It has at least one alkoxy group or phenoxy group having 1 to 2 carbon atoms as a side chain group. ) The ratio of the bonding units (1) and (II) in the organosilicon polymer copolymer is expressed as a molar ratio of (T)/[II]=7/3 to 3/
7 and also the bonding units CI) and (II)
The sum of and the proportion of the bonding unit (IV) is expressed as a molar ratio of CI
]+(II)/(IV)=2/1 to 200/1, and the average degree of polymerization is 1000 or more, preferably 1500 to 50000.

The above-mentioned polycarbosilastyrene is M (OR) with the above-mentioned polysilastyrene (where M represents Tt or Zr, and R
represents an alkyl group or a phenyl group having 1 to 20 carbon atoms.

) as raw materials, and can be manufactured by mixing and heat-treating the mixture.

The inorganic filler in the present invention is at least one selected from the group consisting of oxides, borates, phosphates, silicates, silicides, borides, nitrides and carbides,
Examples of these are as follows.

Magnesium, calcium, barium, titanium, zirconium, chromium, manganese, iron, cobalt, nickel,
Including oxides, carbides, nitrides, silicides, borides of copper, zinc, boron, aluminum, silicon and borates, phosphates, silicates of lithium, sodium, potassium, magnesium, calcium and zinc. .

These may be used alone or in combination as necessary.

Even when the polycarbosilastyrene used in the present invention is heat-treated at IOOO'C in an air atmosphere for 10 hours or more, the weight loss is only 10 to 15% by weight. Therefore, when the coating composition of the present invention is applied to the surface of a substrate,
The resulting coating is less likely to undergo volume shrinkage or cracking due to heating, and the formed coating after heating becomes extremely dense.

Furthermore, by adding an inorganic filler, the adhesion to the substrate is stronger than that of a film formed from polycarbosilastyrene alone, and the heat resistance and flexibility are also improved.
Furthermore, the strength and surface hardness of the coating are increased.

The amount of inorganic filler added is polycarbosilastyrene 100
10 to 900 parts by weight, preferably 30 parts by weight
~300 parts by weight. If the amount of the inorganic filler added is less than 10 parts by weight, the adhesion of the coating to the substrate will decrease. Further, if the amount is more than 900 parts by weight, the adhesion of the coating to the substrate and the flexibility of the coating decrease, which is not preferable.

The coating composition of the present invention is obtained by dispersing or dissolving polycarbosilastyrene and an inorganic filler in an organic solvent.

Examples of organic solvents include toluene, xylene, n-butanol, isobutanol, butyl acetate, mineral spirit,
Solvent naphtha, ethyl cellosolve, butyl cellosolve, cellosolve acetate, etc. are used.

When using the coating composition of the present invention, the coating composition is applied to a metal substrate or a non-metal substrate such as glass, ceramic, firebrick, etc. by brush coating, roll coating, spraying, dipping, etc. , perform dry baking.

A coating amount of 20 to 100 g/rd is generally desirable.

If the coating amount is less than 20 g/rrT, pinholes are likely to occur in the coating, resulting in a decrease in corrosion resistance. On the other hand, 100 g
If the amount is more than /nf, it is not preferable because the coating tends to crack when heated at high temperatures, especially when subjected to cooling/heating cycles.

The baking temperature is preferably 150°C or higher, but if the object to be coated is placed in an environment of 150°C or higher after painting, there is no need to carry out a baking process.
If it is lower than 0°C, the strength of the coating film will be low and the hardness and impact resistance will be poor, which is not preferable.

(Example) This will be explained in more detail below with reference to Examples.

In the Examples, % and parts indicate weight % and parts by weight unless otherwise specified.

Reference Example 1 Equimolar amounts of dichlorodimethylsilane and dichloromethylphenylsilane were polymerized at 110°C in the presence of a Na-dispersed catalyst in a toluene solvent to achieve a softening point of 86-9.
Polysilastyrene at 4°C was obtained.

As a result of nuclear magnetic resonance analysis, this polysilastyrene was composed of

Reference Example 2 The polysilastyrene obtained in Reference Example 1 was heated to 1 at 420°C.
A polycarbosilastyrene (A) having a softening point of 175 to 185'C was obtained by heat treatment under reduced pressure for 5 minutes.

As a result of nuclear magnetic resonance analysis, this polycarbosilastyrene (A) was composed of +CH2-8i-)- units and (-Si-3i ← units in a ratio of 45,755. Also, the number average molecular weight was 4,500. there were.

Reference Example 3 After adding 10 g of tetrabutoxytitanium to 40 g of polysilastyrene obtained in Reference Example 1 and adding 10 d of xylene, the temperature was gradually raised in a nitrogen stream, and when the temperature exceeded 100°C, stirring was stopped. It started. The temperature was raised to 350°C over 3 hours, maintained at this temperature for 2 hours, and then allowed to cool to room temperature.
4.3 g of polycarbosilastyrene (B) was obtained.

As a result of nuclear magnetic resonance analysis, this polycarbosilastyrene (B) is composed of + CHz S 1->- units and +5i-3i ← units in a ratio of 40:60, and the sum of these and +Ti -0←unit ratio was 10:1. Further, the number average molecular weight was 3,500.

Example 1 Polycarbosilastyrene (A) 10 obtained in Reference Example 2
0 parts, 100 parts of titanium dioxide as an inorganic filler, and 100 parts of xylene were kneaded in a mixer to obtain a coating composition.

On the other hand, a stainless steel plate (SUS316L) with a thickness of 0.6 ml was degreased with acetone and air-dried as a base material.

Next, the coating composition was coated on the base material to a thickness of about 20 μm using a bar coater, and heated at 300"C in an air oven for 1 hour.
After baking for an hour, it was slowly cooled.

In order to evaluate the adhesion of this film to the base material,
After exposing the painted samples in an air oven for 2 hours at °C.
After taking it out of the oven and slowly cooling it in the air, make cross cuts at a pitch of 1 m on the film using a cutter knife, apply adhesive cellophane tape to these parts, and then peel it off quickly to see if the film peels off. When examined, no peeling of the film was observed, indicating excellent adhesion.

In addition, in order to evaluate the corrosion resistance of the coating, a painted sample was immersed in a 4% NaOH aqueous solution for 100 hours, washed with water, dried, and examined for peeling of the coating. No peeling of the coating was observed. It showed excellent corrosion resistance.

Furthermore, in order to evaluate the flexibility of the film, the painted sample was bent 180 degrees with a 5 mm RO curvature, adhesive cellophane tape was pasted on this part, and the film was examined to see if it peeled off after rapidly peeling it off. However, no peeling of the film was observed, indicating excellent flexibility.

Example 2 A coating composition was obtained in the same manner as in Example 1, except that titanium dioxide was replaced with the inorganic filler shown in Table 1.

Next, coating samples were obtained in the same manner as in Example, and the adhesion, corrosion resistance, and flexibility of the coatings were examined.

The results are shown in Table 1.

Example 3 A coating composition was obtained in the same manner as in Example 1, except that titanium dioxide was replaced with the inorganic filler shown in Table 1.

Next, a 3.0 mm thick alumina sintered plate (
A coating sample was obtained in the same manner as in Example 1, except that 96% purity was used, and the adhesion, corrosion resistance, and flexibility of the coating were examined. The results are shown in Table 1.

Examples 4 to 6 In Examples 1 to 3, the polycarbosilastyrene (B) obtained in Reference Example 3 was used, and the titanium dioxide was replaced with the inorganic filler shown in Table 1. A coating composition was obtained in the same manner as above.

Next, a coating sample was obtained in the same manner as in Example 1, and the adhesion, corrosion resistance, and flexibility of the coating were examined.

The results are shown in Table 1.

Comparative Examples 1 to 2 Coating compositions were obtained in the same manner as in Examples 1 and 4, except that no inorganic filler was added.

Next, a coating sample was obtained in the same manner as in Example 1, and the adhesion, corrosion resistance, and flexibility of the coating were examined.

The results are shown in Table 1.

Comparative Examples 3 to 4 A coating composition was obtained in the same manner as in Example 1, except that the amount of titanium dioxide added was changed to the amount shown in Table 1.

Next, a coating sample was obtained in the same manner as in Example 1, and the adhesion, corrosion resistance, and flexibility of the coating were examined.

The results are shown in Table 1.

Comparative Example 5 A coating composition was obtained in the same manner as in Example 1, except that polycarbosilastyrene was replaced with polycarbosilane (number average molecular fil 200).

Next, a coating sample was obtained in the same manner as in Example 1, and the adhesion, corrosion resistance, and flexibility of the coating were examined.

The results are shown in Table 1.

Claims (1)

[Claims] 1. A coating composition comprising 10 to 900 parts by weight of an inorganic filler dispersed or dissolved in an organic solvent based on 100 parts by weight of polycarbosilastyrene.