JPH01168A - Silicon alkoxide coating agent - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a silicon alkoxide coating agent used, for example, on a painted surface where a coating film with weather resistance and hardness is required.

[Background technology]

Silicon alkoxide coating agents are weather resistant and can produce highly hard coatings, so they can be applied to the surface of substrates made of chemically weak materials such as plastic, wood, and cement to protect them. things are being done. In this silicon alkoxide coating agent, silicon alkoxide undergoes hydrolysis and condensation, resulting in Mw and M
Unless w/Mn falls within a certain range, a uniform, high-quality coating film cannot be obtained. Here, Mw is the weight average molecular weight, and Mn is the number average molecular weight.

Silicon alkoxide coating agents include one-component type silicon alkoxide coating agents that are prepared by adding catalysts and curing agents to silicon alkoxide in advance and are stored in a ready-to-use state, as well as monomers, catalysts, and curing agents. There is a two-component type that has two parts. −
The liquid type contains only N when used, but it has poor storage stability and can only be stored in a cool, dark place for about one month. On the other hand, for the two-component type, for example, when using, mix an appropriate amount of liquid B containing a curing agent and catalyst with liquid A, which has silicon alkoxide as the main ingredient, to achieve the desired Mw or Mw/Mn. Therefore, it is storage stable, but it takes a considerable amount of time (this is called the "aging time") for Mw and Mw/Mn to reach the desired values after mixing the B solution with the A solution. ) and the workability is very poor. In this case, if you try to shorten the aging time and increase the amount of catalyst mixed, etc., the speed of the condensation reaction will be too fast and the Mw/Mn
There has been a problem in that the time during which is maintained at a desired value (this is referred to as "life") becomes short. Furthermore, since the amount used for building materials is large and therefore the amount stored is large, there is also the problem that it is difficult to store it in a cool, dark place.

[Purpose of the invention]

In view of these circumstances, this invention has good storage stability when not in use, short maturing time when in use, and
Moreover, the purpose is to provide a silicon alkoxide coating agent with a long life.

[Disclosure of the invention]

In order to achieve such an object, the present invention provides a silicon alkoxide coating agent in which a catalyst and a curing agent are added to silicon alkoxide. weight average molecular weight) is 200 to 400,
Liquid A adjusted so that Mw/Mn (number average molecular weight) is 1.0 to 1.2, and a catalyst and curing agent that are added to this liquid A at the time of use to prepare a coating agent. The gist of the invention is a silicon alkoxide-based coating agent characterized in that it is formed in combination with liquid B containing at least a curing agent.

The present invention will be explained in detail below.

As silicon alkoxide, the general formula is R7Si (
OR' ) 4-, , where n=o ~3. R is an alkyl group having 1 to 4 carbon atoms (epoxy group, amino group).

may contain acrylic groups, etc.), R' has 1 to 1 carbon atoms
4 alkyl group] as a main component and filled with an inorganic substance such as Tie as a filler. For example, as a SiO□ component, Si (OR' ) 4 or silica sol 30 to 200 parts by weight (solid content in the case of silica sol) (either silica sol or water-dispersed silica sol), R3i (OR'
) 3 is 100 parts by weight, RzSiQ component is R2S i (OR' ) z
It is preferable to mix 13 to 50 parts by weight of the following. For this combination, 5 to 10
It becomes easier to obtain a coating film suitable for use as a building material with a thickness of approximately μm (it is possible to increase the thickness to approximately 20 to 40 μm if pigments are added). Furthermore, surfactants, thickeners, colorants, etc. may be added depending on the purpose.

Liquid A is a prepolymer obtained by adding and mixing a diluting alcohol, a curing agent (water), and a catalyst to the silicon alkoxide (since the main chain is composed of siloxane bonds, hereinafter referred to as "siloxane prepolymer"). ”)
It is formed by il.

Siloxane prepolymer has Mw (weight average molecular weight)
is 200~400. The Mw/Mn (number average molecular weight) is adjusted to be 1.0 to 1.2.

Solution A prepared in this manner can be stored at room temperature for several months or more if kept tightly capped. When Mw is less than 200, storage stability is achieved, but it takes too long to ripen during use. 40
If it exceeds 0, storage stability may decrease or life may be shortened (
Otherwise, the desired high hardness coating film cannot be obtained.

Moreover, when Mw/Mn exceeds 1.2, storage stability decreases.

In liquid A, 80% or more, preferably 90% or more of the terminal ends of the siloxane prepolymer are preferably alkoxides. In other words, by converting the terminals of the siloxane prepolymer into alkoxide and eliminating residual moisture, GoSi -OR+H! O→ESi-OH+ROH"1a
st-OR+1lO-si=→=st-0-Si:
+ ROH Mi Si -OH+IIo-Si ox → Ra5i-
It is preferable to prevent the three reactions 0-3i+11□0 from occurring to improve storage stability. 80
% or less, the reaction may proceed during storage and result in polymerization, or the hardness of the coating film may not be sufficient after painting. Then, the end of the siloxane prepolymer is prepared as described above, and at the time of use, liquid B is added to quickly cause the above three reactions to quickly obtain the desired coating agent. And make it possible to have a long life.

Mw, Mw/Mn, and the ratio of the alkoxide at the terminal of the siloxane prepolymer are controlled by controlling the amounts of water as a curing agent and the amount of the catalyst added, but among these, water has a strong influence. The amount of water added is preferably 1 wt% or more and 12 wt% or less based on the silicon alkoxide.

When it is less than 1 wt%, storage stability is good, but the ripening time becomes long. - On the other hand, if it exceeds 12 wt%, problems will arise in storage stability.

Examples of catalysts include sulfuric acid, hydrochloric acid, and nitric acid.

Phosphoric acid, perchloric acid, formic acid, acetic acid, propionic acid.

At least one type of acidic catalyst is used, such as a dilute solution of an inorganic acid and/or an organic acid using oxalic acid, citric acid, malonic acid, trichloroacetic acid, etc. alone or in combination.

When using an acidic catalyst, the amount contained in liquid A and liquid B is 50 ppm to 5 ppm based on the silicon alkoxide.
000ppm, more preferably 50ppm to IQOOp
It is pm. If it is less than 50 ppm, the aging time will be very long. Sooo.

If it exceeds ppm, storage stability and life tend to be adversely affected. In addition, the above 50 to 5000p
When using an acidic catalyst in the pm range, it is preferable to add at least 20 wt % or more of water as a curing agent to the solid content of the coating liquid; otherwise, there is a tendency that sufficient film-forming properties cannot be obtained.

As the diluted solution, lower alcohols such as methanol and ethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, acetic ester, etc. are used alone or in combination.

When using, add liquid B to liquid A and adjust the Mw to 400~
1600, more preferably 500-1600, Mw/M
n is 1.1 to 1.8, more preferably 1.2 to 1.8
Prepare so that The B liquid consists of at least a curing agent such as water, and a catalyst, a solvent, etc. are added as necessary.

When Mw is less than 400, cracks tend to occur during film formation, making it difficult to overcoat, and furthermore, peeling tends to occur.

On the other hand, if it exceeds 1600, the gloss and transparency may decrease, or the hardness of the coating film may decrease, and it becomes difficult to recoat. When M W /M n is less than 1.1, the coating film tends to crack or peel easily. When M w /Mn exceeds 1.8, the gloss, transparency and hardness of the coating film tend to be insufficient.

Note that the values of Mw and M w / M n above exclude the prepolymer bonded to the filler when the coating agent contains the filler.

Liquid B consists of at least a hardening agent such as water.・Catalysts and solvents are added as necessary.・In this case, the amount of water added as a hardening agent is 30% of the solid content of the coating agent. ~200 wt%, preferably
It is in the range of 40 to 170 wt%. The solid content here refers to the content that ultimately remains as a coating film. Addition amount is 30-
If it is less than t%, the ends of the siloxane prepolymer remain alkoxide, making it difficult to polymerize, and when a coating film is formed, there is a tendency for film forming properties to deteriorate and cracks to occur. On the other hand, if it exceeds 200 wt%, polymerization tends to proceed too much and the life tends to be shortened.

In addition to the above catalysts, the following catalysts may be used for liquids A and B. For example, (Cs H
s) RMeXa-,1 (hereinafter referred to as "cyclopentadiene catalyst") can be used. in particular,
Examples include dicyclopentadienyl zirconium dichloride and dicyclopentadienyl titanium dichloride. The amount of this catalyst added is 130% based on silicon alkoxide.
ppm to 13,000 ppm or less, especially 400 to 7,000
ppm is preferred. Below 130 ppm, there is almost no catalytic effect. If it exceeds 13,000 ppm, no increase in the catalytic effect can be expected and the life tends to be shortened. Even if an acidic catalyst and a cyclopentadiene catalyst are used together, the appropriate value of the amount added does not change.

Moreover, aminosilane can also be used as a catalyst.

The amount of aminosilane added is 1100 pp to 110 pp to silicon alkoxide, regardless of the amount of acidic catalyst added.
000 ppm or less, particularly preferably 200 to 7000 ppm. When the amount added is less than 1100 pp, there is almost no catalytic effect. If it exceeds 110,000 pp, the life of the liquid tends to be shortened and the hardness of the coating film tends to decrease.

As aminosilane, γ-aminopropyltriethoxysilane (HJ(CHz)*5i(OCJs)3),
N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (HzN(CHz) zNH(CHz)
:+Si (OCHt) z), N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane (H
J(CHz) tNH(CHz)ssicJ(OC11
3) z), etc.

Furthermore, the following catalysts can also be used.

Metal salts of inorganic acids, metal salts of organic acids, quaternary ammonium salts of inorganic acids, quaternary ammonium salts of organic acids, amine salts of inorganic acids, and amine salts of organic acids can be used as catalysts. In this case, the type of acid is hydrochloric acid, nitric acid, phosphoric acid,
Examples include formic acid, acetic acid, propionic acid, etc., and metal types include Pb, Fe, Co, Mn, Zn, etc. Types of amines include trimethylamine and triethylamine.

Examples include n-butylamine. Moreover, metathesis salts of the above-mentioned salts can also be used as catalysts. The amount added is preferably in the range of 50 to 15,000 ppm based on the silicon alkoxide. If it is less than 50 ppm, the catalytic action is too small and there is little point in adding it, and if it exceeds 15,000 ppm, not only is no increase in the catalytic action seen, but there is also a tendency for the life to be shortened and the hardness of the coating film to be lowered. - Organotin compounds can also be used as catalysts. For example, dibutyltin methoxide, dibutyltin dilaurate,
Examples include dibutyltin dioctate. The amount added is preferably in the range of 50 to 15,000 ppm based on the silicon alkoxide. If it is less than 50 ppm, the catalytic effect is too small and there is little point in adding it, and if it exceeds 15,000 ppm, not only will there be no increase in the catalytic effect, but there will also be a tendency for the life to be shortened and the coating hardness to decrease. When a plurality of each of the above catalysts is used in combination, it is desirable to use each catalyst in a preferable addition amount range when used alone.

The above preparation is preferably carried out at a temperature of 80°C or lower.

The silicon alkoxide coating agent prepared in this way is applied to the object to be coated and heated.
A coating film can be formed on the surface of an object to be coated.

The heating conditions are preferably 50 to 200°C; below 50°C, it is difficult to cure, and above 200"C, it tends to be easily cranked. The coating method is not particularly limited, but spray painting, roll coating, etc. Examples include painting, flow coater painting, and dip painting.

Next, Examples and Comparative Examples will be explained.

A silicon alkoxide as a main ingredient and a solvent were blended in the following proportions.

Methyltrimethoxysilane
100 weight 1 part tetramethoxysilane
20 heavy 1
Part IPA-shi! J*Zo 1L (OSCAL1432.5i
Ot30'ri 1 0 5 parts by weight DimethyB dimethoxysilane 3
0 heavy fi part isopropanol (IPA)
100 parts by weight)
IPA-silica sol is manufactured by Catalyst Kasei.

This silicon alkoxide was blended with the types of catalysts shown in Table 1 and water in the amounts shown in the table to prepare Solution A. In addition, the formulation was performed under an atmosphere of 25° C. with stirring at 10Q Orpm or 500 rpm+n for 10 to 30 minutes.

After storing this At& in a sealed state for more than one week at 25°C, changes in liquid viscosity and gelling molecular weight were observed.

We also looked at the state of the alkoxide at the end of the siloxane prepolymer. The results are shown in Table 1.

The molecular weight is determined by GPC (gel permeation chromatography).
The condition of the alkoxide at the end of the prepolymer is determined by FT (Fourier transform) -1R.
(manufactured by JEOL Ltd.), FT (Fourier transform)-NMR (
(manufactured by JEOL Ltd.).

Next, add the amount of water and catalyst shown in Table 1 to A.
In addition to the liquid, a coating liquid was prepared.

The mixture was stirred at 11,000 rpm for 10 minutes in an atmosphere of 25°C.

During this preparation, the Mw coating liquid should be 400 or more, M
Time until w/Mn becomes 1.1 or more (aging time), Mw is 400 or more, Mw/Mn is 1
After ゜2 or more, Mw becomes 1600, M w /
Measure the time (life) until Mn exceeds 1.8,
The results are shown in Table 1. In Table 1, E of the catalyst is hydrochloric acid, G is dicyclopentadienylzirconium dichloride, T is dicyclopentadienyltitanium dichloride, and N is N-(β-aminoethyl)-r-aminopropyltrimethoxysilane. , Z is (Ct Hs)z
Z r C11, GA is ammonium formate, D is dibutyltin dilaurate, and γ is T-aminopropyltriethoxysilane.

As shown in Table 1, the products of each Example had better storage stability, shorter maturation time, and longer life than those of the Comparative Examples.

Furthermore, by adding water and catalyst to liquid A, Mw is 400, M
State until w/M n becomes 1.1 (first state)
coating liquid, Mw is 400 or more, Mw/M n
After becoming 1.1 or more, Mw becomes 1600, Mw/M
The coating liquid in the state until n reaches 1.8 (second state), the coating η in the state where Mw /Mn exceeds 1.8 (third state), and the base Spray coat onto an alumina substrate measuring 1Qcm square and 1cm thick, let it set for 2 minutes at room temperature, heat it in a drying oven at 130°C for 20 minutes, and apply a 10cm thick coating for each coat. A membrane was obtained. The film forming properties and the state of the coating film were examined at that time, and the results are shown in Table 2. In the case of overcoating, the same conditions were applied.

JTSA5403 asbestos slate flexible board (
A flexible board with a thickness of 6fl, 12ao x 18cm) was prepared, and in the case of the example shown in Table 4, a coating film with a thickness of 10 μm was formed in the same manner as above, and the flexible board on which the coating film was formed was immersed in hot water at 60'C. We then investigated the occurrence of the crank. Tested. The results are shown in Table 4. Note that a primer layer having a thickness of 5 μm was previously formed on this plate as a primer layer. As the material for forming the primer layer, a silicon-modified urethane material (manufactured by Next Summer Silicone Co., Ltd.) was used.

Further, Table 3 shows the hardness of the coating film obtained from the coating liquid in each state (first to third states) in each of the above examples and some of the comparative examples. In addition, the hardness is JIS K
Pencil hardness according to -5400.

Table 3 (Part 1) Table 3 (Part 2) Table 3 (Part 3) As shown in Table 4 and Table 2, all of the examples were coated in the second state, that is, the aging time was It maintains a good gloss from the time it is applied until the end of its life, and it does not peel off even after multiple coats.

There was no crack. As shown in Table 4, it can also be seen that it has excellent water resistance. In addition, in Table 2, 2
What is written as 2 coats and 2 bakes means that the process of painting and baking is performed.

〔Effect of the invention〕

Since the silicon alkoxide coating agent according to the present invention has the above-mentioned structure, it has good storage stability when not in use and is suitable for large-scale storage such as for building materials, and has a long aging time when in use. It has a short and long life, and a glossy and highly hard coating film can be stably obtained.

Agent: Takehiko Matsumoto, Patent Attorney: Hikoyumi Matsumoto, JE Publication (Spontaneous, September 2, 1988, Tokuro Kada No. 153891, No. 2, Name of Invention: Silicon alkoxide-based coating agent 3.1 Person who makes the gong 1) ■Conspiracy with Cows■ Patent Applicant Office
1048 Oaza Kadoma, Kadoma City, Osaka Name (583) Matsushita Electric Works Co., Ltd. Representative f Masato Fujii 4, no agent crPl [t18bZ-113891 No. 6, Specification subject to amendment 7, Contents of amendment ■ On page 15, line 12 of the specification, "tetramethoxysilane" is corrected to "tetraethoxysilane."

■ On the second line of page 16 of the specification, the phrase “1 round” has been replaced with “1 lap”.
"Weekly," he corrected.

Claims (5)

[Claims] (1) In a silicon alkoxide-based coating agent in which a catalyst and a curing agent are added to silicon alkoxide, the Mw (weight average molecular weight) of the siloxane prepolymer is 20.
0-400, Mw/Mn (number average molecular weight) 1.0-1
．． 2, and Liquid B, which is added to this A liquid to prepare a coating agent at the time of use, and contains at least a curing agent of a catalyst and a curing agent. A silicon alkoxide coating agent characterized by: (2) Preparation of coating agent with Mw of 400 to 160
0. The silicon alkoxide coating agent according to claim 1, which is coated so that Mw/Mn is 1.1 to 1.8. (3) The silicon alkoxide coating agent according to claim 1 or 2, wherein 80% or more of the terminal ends of the siloxane prepolymer are alkoxide. (4) Any of claims 1 to 3, wherein the curing agent added to liquid A is water, and the amount added is in the range of 30 to 200 wt% based on the solid content of the coating agent. The silicon alkoxide coating agent described in Crab. (5) As a catalyst (C_5H_5)_nMeX_4_-
_n [However, C_5H_5 is cyclopentadiene, M
e is an element in the 4th to 6th period of Group IV of the periodic table, X is a halogen element, and n is 1 to 3. ], aminosilane, inorganic acid,
Organic acids, metal salts of inorganic acids, metal salts of organic acids, quaternary ammonium salts of inorganic acids, quaternary ammonium salts of organic acids,
The silicon alkoxide coating agent according to any one of claims 1 to 4, wherein at least one of the group consisting of an amine salt of an inorganic acid, an amine salt of an organic acid, and an organic tin compound is used.