JPS62283164A - Surface coating material - Google Patents

Abstract

PURPOSE:A surface coating material, consisting of an organopolysilazane having a specific basic skeleton and capable of giving coats having improved heat, weather and chemical resistance, flexibility, rust preventing property, etc. CONSTITUTION:A surface coating material obtained by dehydrogenating and polymerizing an organosilazane expressed by formula I (R is H, 1-6C monofunctional hydrocarbon, 1-6C alkoxy, 1-6C alkenoxy, etc.; a>0, b<=2; 0<a+b<3), e.g. obtained by converting one or more chlorosilanes, e.g. H2SiCl2, etc., into the silazane, in the presence of a basic catalyst, preferably potassium hydride, etc., in an organic solvent e.g. ethyl ether, etc., to give an organopolysiloxane having >=1 basic skeletons expressed by formula II, directly using or dissolving the resultant organopolysilazane in an organic solvent, applying the formed solution to the surface of a synthetic resin, etc., and heating the resultant coating layer, etc, to form coats.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention C Industrial Application Field This invention relates to a surface coating material made of organopolysilazane, and more specifically, the present invention relates to a surface coating material made of organopolysilazane.
The present invention relates to a surface coating material that can form a highly hard coating with excellent heat resistance, flexibility, weather resistance, rust prevention, chemical resistance, etc.

[Prior art and its problems] Conventionally, the quality of various products has been improved by protecting the surfaces of various base materials such as various plastics, metals, and ceramic materials, and by improving their appearance.

Or in order to attach the top to the surface of various base materials,
Various coating layers have been formed on the surface of substrate materials.

However, at present, there is no surface coating material that can form a highly hard coating with excellent heat resistance, flexibility, weather resistance, rust prevention, chemical resistance, etc. Only surface coating materials have been put into practical use.

For example, thermal surface coating materials include sodium silicate and polysilicade, which can form a glassy layer by curing, but these have poor flexibility and impact resistance, and dimethylpolysiloxane, phenyl Polynoroxanes such as methylpolysiloxane and polytetrafluoroethylene have drawbacks such as poor surface hardness and poor heat resistance at temperatures above 500°C. Furthermore, conventional heat-resistant surface sealing materials have the disadvantage of causing "blisters" and cracks when heated.

Furthermore, silicone ladder polymer is known as a surface coating material having excellent heat resistance and corrosion resistance.

However, this silicone ladder polymer has many disadvantages such as being difficult to manufacture and being poorly soluble in organic solvents.

Therefore, it was proposed as a ceramic precursor (Japanese Patent Laid-Open No. 1983-
226890)) Si-N-N
-S i - If an organopolysilazane having a four-membered ring structure is used as a surface sealing material, the four-membered negative ring structure marked with # is excellent because it is thermally stable and similar to the silicone ladder polymer skeleton. ji4 maturity is expected.

JP H-141758, JP 60-1458
The silazane bonding compositions conventionally proposed in Publication No. 15 and Japanese Patent Application Laid-open No. 80-163988, etc., have a surface protection material,
It is said to be excellent as a rust-preventive coating material, and in particular, silazane bonds combine with moisture in the air to form active silanol groups, and these silanol groups are physically and chemically bonded to the surfaces of plastics and various inorganic base materials. It is said that it forms a film that is not easily peeled off because it adheres to the surface.

However, even though these silazane compounds have a 4t1 ring structure and have good curability, and the cured products have excellent adhesion and film strength.

Since the cured film is inferior in surface hardness, heat resistance, thermal shock resistance, flexibility, etc., it is not yet perfect as a surface coating material.

On the other hand, rust-preventing processing methods for metal plates such as steel plates include phosphoric acid treatment, chromate treatment, aluminum plating treatment, zinc plating treatment, etc., and chromate treatment is said to have the greatest rust-preventing power.

However, when a rust preventive film is formed on a metal surface by chromate treatment, hexavalent chromium is used, so wastewater treatment must be completed, which is extremely complicated.

[Purpose of Issue 11] This invention has been made based on the above circumstances.

That is, an object of the present invention is to provide a surface coating material that can form a highly hard film with excellent heat resistance, flexibility, weather resistance, rust prevention, chemical resistance, etc. on the surface of various base materials. The goal is to provide the following.

[Means for achieving the above objectives] The above objectives are 1! The gist of this invention to achieve
)Formula %Formula % (However, in the first formula, R is a hydrogen atom, a monovalent hydrocarbon group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and 1 carbon number.
~6 alkenoxy groups, dryalkylsilylno^ and dialkylsilyl groups having an alkyl group having 1 to 6 carbon atoms, and dialkylamino groups having an alkyl group having 1 to 6 carbon atoms. This is a surface coating material characterized by being made of organopolysilazane containing one or more organopolysilazane in one molecule.

Examples of the iin-N1 degree λ group as R in the first formula of JILT include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hequinyl group, a vinyl group,
propenyl group, butynyl group, allyl group.

Examples include phenyl group and cyclohexyl group.

+iii) Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxyno-X.

Examples include petoxy group, hekynoxy group, vinyloxy group, impropenoxy group, allyloxy group, and phenoxy group.

Examples of the trialkylsilyl group having 1 to 6 carbon atoms include trimethylsilyl group, triethylsilyl group, triprobylsilylno^, tributylsilyl group, tripentylsilyl group, trihexylsilyl group, ethyldimethylsilyl group, and diethylmethyl group. Examples include silyl group, dimethylphenylsilyl group, diethylphenylsilyl group, and the like.

carbon! Examples of the dialkylsilyl group of ¥1 to ¥6 include dimethylsilyl group, diethylsilyl group, dipropylsilyl group, dibutylsilyl group, dialkylsilyl group, dihenylsilyl group, methylethylsilyl group, ethylpropylsilyl group, etc. can be mentioned.

Examples of the dialkylamino group having an alkyl group having 1 to 6 carbon atoms include dimethylamino group, diethylamino group, dipropylamino group, dibutylamino group, dialkylamino group, dialkylamino group, methylethylamino group, and ethylpropylamino group. Examples include groups.

Among the above various H, water; JrX atom and carbon number 1-
6 lower alkylno, ( is preferred, and a hydrogen atom and a methyl group are particularly preferred.

Synthesis of polyorganosilazane a- This organopolysilazane can be produced as follows.

That is, Equation (2).

Ra Hb Si (NH) <a-a-b) N2(
2) (However, in the first formula, R is a hydrogen atom, and has 1 to 6 carbon atoms.
monovalent hydrocarbon group, aryloxy group having 1 to 6 carbon atoms, alkenoquino group having 1 to 6 carbon atoms, carbon t! Represents a dialkylsilylno^ and dialkylsilyl group having an alkyl group of il to 6, and a dialkyl7mino group having a furkyl group having 1 to 6 carbon atoms, and each of a and b is
It is a positive number that satisfies O<a, b≦2.0<a+b<3. ) is dehydrogenated using a basic catalyst.

R in the formula (2) above has the same meaning as R in the formula (1) in 11g1, and each of a and b is 0
It is a positive number satisfying <a, b≦2, Q<a+b<3.

Synthesis of m-organosilazane-1 Such organosilazanes are e.g.

H2Si Cuz, H5i C1y,
Si Oln.

CH) SiHCI, CH) SiCIJ, (CH Go)2
sicfi2, CCH3)3SiC1, C6H55iC
13, (C6H5)2SiC! ;L? , Cb
H5CH3Si C cross 2, CH2=CH3i
C≦L, CH2=CHCH2SiC 1, C
6H5Si C 7, C2H5SiC 3
, CH3 (CHI 0) Si C cross? ,
CHI(C2H50)Si C2, (CH
3) 2 Si HCl, CH3(C6Hs
0) Si Cup, (CH3)2NSi
C1x, (CHI)2 NCHIS
It can be easily synthesized by converting a mixture of one or more glorosilanes such as iHCi into silazane.

Examples of reaction solvents during synthesis include ethers such as ethyl ether, tetrahydrofuran, tetrahydropyran, and dioxane, halogenated hydrocarbons such as methylene chloride, chloroform, and carbon tetramide, hexane, heptane, octane, petroleum ether, Aliphatic iR-modified water such as ligroin and kerosene, aromatic hydrocarbons such as benzene, toluene, and xylene, and the like can be used.

Among the various reaction solvents, ethers and aromatic hydrocarbons are preferred.

After separating the ammonium chloride produced as a by-product during the synthesis of organosilazane, the reaction solvent is distilled under reduced pressure to obtain an oily or crystalline organosilazane represented by the formula tjSZ.

11 Theory Hydrogen Polymerization 11 The organosilazane represented by the above-mentioned formula 2 is produced by reacting in the presence of a basic catalyst in an organic solvent, for example, and
Tree bonded to X atom; J atom and hydrogen atom bonded to nitrogen 20 atom undergo dehydrogenation polymerization within and/or intermolecularly. As a result, when an organosilazane represented by (R5i HNH)n is used as a starting material, a polyorganosilazane represented by formula (3) or (4) can be obtained.

Φ ・ ・ (3) ・ ・ ・ (4) (In the above formulas (3) and (4), R has the same meaning as above, and x, y, z, m, and n are each Examples of the basic catalyst (which independently represents O or a positive integer) include potassium hydride, sodium hydride, and calcium hydride.

Examples include sodium amide, butyl lithium, lithium aluminum hydride, sodium methylate, sodium ethylate, potassium siliconates, sodium siliconates, and cesium siliconates. In this respect, potassium hydride and sodium amide are preferred.

Further, as the organic solvent during the dehydration X polymerization, the same solvents as those used during the synthesis of the organosilazane can be used, and among them, ethers are preferable. Preferably, ethyl ether or tetrahydrofuran is used.

The reaction temperature during the dehydrogenation polymerization is usually from room temperature to the reflux temperature of a 1 m thick melt.

When the dehydrogenation reaction is completed, no hydrogen gas is generated, so it is preferable to add an electrophilic compound to the reaction system at that point.

Examples of the electrophilic compound described in +iii include organic halides such as methyl iodide, ethyl iodide, benzyl chloride, and acyl mide; alcohols such as methyl alcohol and ethyl alcohol; organic carboxylic acids such as acetic acid and propionic acid; Examples include organic sulfonic acids such as P-)luenesulfonic acid, chlorosilanes such as trichlorosilane, boron halides such as boron trifluoride, and cyanuric chloride.

For example, by removing the reactant of the electrophilic compound and the basic catalyst by thinning the reaction system with 1iib, and by distilling the organic solvent under reduced pressure, the oily or crystalline
1) An organopolysilazane having the structure shown in the formula can be obtained.

- Organopolysilazane as a surface coating material - The organopolysilazane in this invention is used alone or together with other additives as a surface coating material to form coating layers on the surfaces of various base materials.

This polyorganosilazane is soluble in the organic solvent.

Therefore, the formation of the coating layer can be realized by dissolving the polyorganosilazane in the various solvents and applying the polyorganosilazane-containing organic solvent solution to the surface of the base material.

Also, if this organopolysilazane is in the form of an oil,
The YQ layer can also be formed by directly applying this organopolysilazane onto the surface of the base material.

The base material is not particularly limited and includes, for example, clay, resin, rubber, metal, wood, and ceramics.

In addition, this organopolysilazane is not limited to coating the surface of molded products made of the above-mentioned base materials, but can also be applied to the surfaces of woven materials such as glass fibers and carbon fibers, and to the surfaces of powders such as mica powder, silica powder, and alumina powder. A covering layer can be formed.

The concentration of organopolysilazane in the organic solvent solution cannot be specified as it varies depending on the types of the various base materials and the thickness of the coating layer to be formed, but it is usually 1. ~50% by weight is sufficient.

There are no particular restrictions on the method of applying the polyorganosilazane-containing organic solvent solution to the surface of the base material, and various methods such as brushing, dipping, and spray coating can be employed.

After applying an organic solvent solution of organopolysilazane to the surface of a base material and removing this organic solvent, or after applying an oily organopolysilazane to the surface of a base material, the silylamine and/or A cyclic silazane bond is hydrolyzed by moisture in the air at room temperature to form a silanol group or a siloxane bond. In addition, some of the silanol groups generated as described above contribute to V: youthfulness with the surface of the base material,
Some of the remaining silanol groups are gradually converted into siloxane at room temperature, or quickly converted into siloxane by heating. In addition, silylamine and silazane bonds, which are relatively difficult to hydrolyze, can be removed by heating! Easily condenses with silanol groups to form siloxane. As a result, a cured film is formed on the surface of the base material.

Here, the heating temperature is usually 50°C or higher, preferably 150°C or higher. The heating time is usually 10 minutes or more. When curing at room temperature,
A few hours is usually sufficient for the curing time.

In this way, a film made of organopolysilazane can also be formed by heating, so organopolysilazane powder is directly applied to the surface of the base material and heated. It can also be formed by so-called powder coating.

Is the coating layer made of organopolysilazane 5i2N? 4g
It is estimated that it is a polymer with a one-ring ladder-like structure, so it has high hardness, flexibility, heat resistance, thermal shock resistance, mechanical shock resistance, mosquito resistance, chemical resistance, and corrosion resistance. It has the following characteristics. In particular, when the content of (CH3Si HNH)n is, for example, 80
The cured film of organopolysilazane obtained by dehydrogenation polymerization of % or more of organopolysilazane has extremely good heat resistance, as it hardly loses 1 weight even when heated up to about 1200°C. Moreover, the above (1)
) The structure shown by the formula is finally converted to 5i02 /S by heating.
Since it is decomposed and converted to tC/5i3Ni, it exhibits excellent lI48 properties even when exposed for a long time under high temperature conditions.

Therefore, the organopolysilazane of the present invention exhibits excellent rust prevention properties when a coating layer thereof is formed on a metal surface, and is therefore suitable as a rust preventive material. Once formed, it is suitable as a surface protection material for preventing damage and imparting weather resistance. When ceramic powder with this coating layer formed on the particle surface is sintered, a consolidated IE with good mechanical impact resistance can be obtained. Since an excellent ceramic sintered body can be obtained, it is also suitable as a binding material for ceramic powder, and if a coating layer thereof is formed on the surface of fibers, it is suitable as a fiber sizing agent.

Furthermore, this organopolysilazane is also suitable as a coating material for covering various electronic components such as chip electronic components, transformers, transistors, resistors, and capacitors.

[Effects of the Invention] According to the present invention, heat resistance, flexibility, rust prevention, weather resistance, chemical resistance, thermal shock resistance, and mechanical resistance can be imparted to the surface of various base materials by curing at room temperature or by heating. It is possible to form a highly hard coating layer with excellent impact resistance. A fumed surface coating can be provided.

[Example] Next, examples and comparative examples of the present invention will be shown.

(Example 1) Excess ammonia was blown into a 20% ethyl ether solution of methyldichlorosilane at room temperature to form a silazane, and the by-produced ammonium chloride was separated out, and the ethyl ether was distilled under reduced pressure to form a viscous liquid. Yes (CH3Si HN
H)n [where n=4 to 5, hereinafter abbreviated as silazane (1). ] was obtained.

A solution of this silazane (1) +00 fi in tetrahydrofuran was subjected to dehydrogenation polymerization at room temperature with 3 parts of potassium hydride. When no hydrogen gas was generated, 30 parts of methyl iodide was added to stop the reaction. Tetrahydrofuran was removed by vacuum distillation, the residue was dissolved in hexane, and by-product potassium iodide was removed using a centrifuge to obtain a 20% hexane solution of methylpolysilazane.

This hexane solution was flow-coated onto a mild steel plate to a film thickness of 3 to 54 m, and after air-drying for 30 minutes,
It was cured for minutes to form a coating layer.

Measure the various properties of this coating layer and share the results with the first
Shown in the table.

(Example 2) The bexane solution obtained in Example 1 was flow-coated onto a mild steel plate in the same manner as in Example 1, and was cured at room temperature for one week to form a coating layer.

Measure the various properties of this coating layer and share the results with the first
Shown in the table.

(Example 3) Excess ammonia was blown into a 20% ethyl ether solution of a chlorosilane mixture having a composition of 80 mol% methyldichlorosilane and 20 mol% methyltrichlorosilane at room temperature to form a silazane, and the same procedure as in Example 1 was carried out. (CH3) 1. OHo, 8Si (NH) 1.
1 [Hereinafter abbreviated as silazane (2). ] was obtained.

Methylpolysilazane was prepared in the same manner as in Example 1 in Tier, except that 100 parts of this silazane (2) solution in tetrahydrofuran was dehydrogenated with 3 parts of potassium hydride and the reaction was stopped by adding 30 parts of methyl iodide. A 20% hexane solution was obtained. In the same manner as in Example 1, this hexane solution was flow coated onto a mild steel plate to form a coating layer.

Measure the various properties of this coating layer and share the results with the first
Shown in the table.

Example 4 20% of a chlorosilane mixture having a composition of 80 mol% methyldichlorosilane and 20 mol% trichlorane
Excess ammonia was blown into the ethyl ether solution at room temperature to form a silazane, and the same procedure as in Example 1 was carried out.
(CH3) o, s H+, o Si (NH)+,
+ [Hereinafter, abbreviated as silazane (3). ] was obtained.

Methylpolysilazane was prepared in the same manner as in Example 1, except that 100 parts of this silazane (3) solution in tetrahydrofuran was dehydrogenated with 3 parts of potassium hydride, and the reaction was stopped by adding 30 parts of methyl iodide. A 20% tetrahydrofuran solution was obtained.

In the same manner as in Example 1, this tetrahydrofuran solution was poured onto an alumina plate to form a layer having a thickness of 5 to 8 gm.

Various properties of this coating layer are measured and the results are
Shown in the table.

(Example 5) The bexane solution obtained in Example 3 was flow-coated onto a polycarbonate plate to a film thickness of 3 to 5 meters, air-dried for 30 minutes, and then cured at 80°C for 2 hours. A coating layer was formed.

Measure the various properties of this coating layer and share the results with the first
Shown in the table.

(Comparative Example 1) 40% of a silane mixture having a composition of 80 mol% methyltrichlorosilane and 20 mol% dimethyldichlorosilane.
0.2 parts of zinc octylate was added to 100 parts of a 20% xylene solution of methylpolysiloxane obtained by cohydrolyzing a 20% xylene solution with isobutanol and wood, and this was applied to a mild steel plate to a film thickness of 3 to 5 g. 30
After air drying for a minute, it was cured at 180° C. for 20 minutes to form a coating layer.

Measure the various properties of this coating layer and share the results with the first
Shown in the table.

(Comparative Example 2) A 50% toluene/isopropanol solution of methylpolysiloxane obtained by cohydrolyzing a 40% toluene solution of methyltrichlorosilane with inpropanol and wood 10
Add 0.5 parts of zinc octylate to 0 parts, and flow-coat this onto an alumina plate to a film thickness of 5 to 8 gm.
After air-drying for a minute, it was cured at 200° C. for 2 hours to form a coating layer.

Various properties of this coating layer are measured and the results are
Shown in the table.

Claims (2)

[Claims] (1) Formula (1)▲There are mathematical formulas, chemical formulas, tables, etc.▼・
...(1) (However, in the first formula, R is a hydrogen atom, a monovalent hydrocarbon group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a carbon number 1
~6 alkenoxy groups, trialkylsilyl groups and dialkylsilyl groups having an alkyl group having 1 to 6 carbon atoms,
It also represents a dialkylamino group having an alkyl group having 1 to 6 carbon atoms. ) A surface coating material comprising an organopolysilazane containing one or more basic skeletons represented by the following in one molecule. (2) The organopolysilazane has the formula (2) RaH
bSi(NH)_(_4_-_a_-_b_)_/_2
(2) (However, in the first formula, R is a hydrogen atom, carbon number 1-
6 monovalent hydrocarbon groups, alkoxy groups having 1 to 6 carbon atoms, alkenoxy groups having 1 to 6 carbon atoms, trialkylsilyl groups and dialkylsilyl groups having alkyl groups having 1 to 6 carbon atoms, and 1 to 6 carbon atoms. represents a dialkylamino group having 6 alkyl groups, a and b each represent 0<a
, b≦2, and 0<a+b<3. ) The surface coating material according to claim 1, which is a polymer obtained by dehydrogenating an organosilazane represented by the following with a basic catalyst.