JP3190301B2 - Primer for non-aqueous porous inorganic substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a primer for a non-aqueous porous inorganic base material. More specifically, a specific silyl group-containing vinyl polymer or a ketone bonded to a hydrolyzable group
Amines having at least one iodine-containing group in the molecule and
Beauty a composition comprising an organic tin compound for non-aqueous-porous inorganic substrate primer based a hardening catalyst.

[0002]

2. Description of the Related Art In recent years, a wide range of inorganic plate-like products for residential use has been developed from a cement extruded plate having a dense surface to a porous ALC.

In general, inorganic base materials such as inorganic plate-like materials have characteristics such as extremely high water absorption and strong alkalinity as compared with plastic base materials and the like. A method of coating and adjusting them and then performing a top coating is employed.

[0004] Among the primers used as described above, epoxy primers have relatively favorable properties.

[0005]

However, in the case of the epoxy-based primer, even those having a dense surface among inorganic base materials, the anchor effect to the base material is not sufficient and the adhesion is poor. Porous materials such as ALC are required to have low shrinkage or elasticity due to their fragile surface, but epoxy-based primers have the drawback that they are hard and cannot be said to have low shrinkage. are doing.

In addition, primer coating is performed not only on a factory line but also on site, and is sometimes used at a low temperature of about 5 ° C. in winter. Therefore, the development of a primer having good low-temperature curability instead of an epoxy-based primer is desired.

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the problems in the epoxy primer, and as a result, have completed the present invention.

That is, the present invention provides: (A) at least a silicon-containing group in which the main chain is substantially composed of a vinyl polymer chain and whose terminal and / or side chain is bonded to a hydrolyzable group in one molecule. One silyl group-containing vinyl polymer (provided that the main chain is substantially a vinyl polymer
Consisting of body chains, hydrolysable on terminal and / or side chains
At least one silicon-containing group per molecule bonded to the group
Containing a silyl group having a glass transition point (Tg) of 10 ° C. or less.
Vinyl-based polymer and polymer whose main chain is substantially vinyl-based
Consisting of a chain, with a hydrolyzable group at the terminal and / or side chain
At least one silicon-containing group bonded to a molecule
Containing a silyl group having a glass transition point (Tg) of 30 ° C. or higher.
And (B) at least one silicon-containing group bonded to a hydrolyzable group per molecule.
The present invention relates to a primer for a non-aqueous porous inorganic base material, which is based on a composition comprising an amine having a number of components and (C) an organotin compound as a curing catalyst.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As one component of a composition serving as a base of a primer of the present invention, a main chain is substantially composed of a vinyl polymer chain, and a terminal and / or a side chain is bonded to a hydrolyzable group. Group-containing vinyl polymer having at least one silicon-containing group (hereinafter also referred to as a hydrolyzable silyl group) in one molecule (provided that the main chain is substantially a vinyl-based polymer).
Consisting of polymer chains with terminal and / or side chains
At least one silicon-containing group bonded to a decomposable group in one molecule;
Silyl having one glass transition point (Tg) of 10 ° C or less
Group-containing vinyl polymer and the main chain is substantially vinyl-based
Consists of united chains and hydrolyzes to terminal and / or side chains
At least one silicon-containing group bonded to a functional group in one molecule.
Silyl groups having a glass transition point (Tg) of 30 ° C or higher
(Excluding the case of having a vinyl polymer) .

The phrase that the main chain of the silyl group-containing vinyl polymer is substantially composed of a vinyl polymer chain means that the main chain is composed of a vinyl monomer unit such as a segment having a urethane bond or a siloxane bond in the main chain. Segments other than the segment, which means that the silyl group-containing vinyl polymer may be contained in a range that does not substantially impair the properties as a vinyl polymer, generally the atom of the atom constituting the main chain Even if a segment other than the segment comprising the vinyl monomer unit is contained in the range of about 50 atomic% or less, the characteristics as the vinyl polymer are not substantially impaired. As described above, since the main chain is substantially composed of a vinyl polymer, the primer is excellent in durability and chemical resistance. Moreover, acrylic urethane on the application of the primer, the effect that adhesion is extremely good between the plies M a is example if the topcoat paint such as acrylic silicone or a liquid acrylic is painted.

The silicon-containing group bonded to the hydrolyzable group is a group containing a group capable of decomposing a group (X) bonded to a silicon atom (Si) into SiOH and XH by hydrolysis. Since such a group is contained in the silyl group-containing vinyl polymer, there is a feature that a silanol group is generated as long as water is present, and a siloxane bond can be generated.

The term "having at least one hydrolyzable silyl group in one molecule at the terminal and / or side chain of the silyl group-containing vinyl polymer" means that the polymer has a main chain terminal or side chain. Has at least one, preferably two or more hydrolyzable silyl groups per molecule.
Since it has at least one hydrolyzable silyl group per molecule, it has a high molecular weight or gels in the presence of moisture, generates a chemically stable siloxane bond, and improves the chemical resistance of the cured product. In addition, since the hydrolyzable silyl group has a good affinity for the inorganic base material and causes a crosslinking reaction due to the presence of moisture, the coating film has good adhesion to the inorganic base material, and the base material has a water absorbing property. Even if it is, the effect of not being adversely affected by the moisture and causing blistering or peeling is obtained.

The molecular weight of one hydrolyzable silyl group present in the silyl group-containing vinyl polymer is about 1,000 to 20,000 in terms of chemical resistance and adhesion. Is preferred.

The molecular weight of the silyl group-containing vinyl polymer is not particularly limited, and is usually from 2,000 to 30,0.
About 00, preferably 3,000 to 25,000
Some are used.

The glass transition point (Tg) of the polymer is not particularly limited. For example, when the Tg is lowered to 10 ° C. or less, the polymer has a characteristic of low shrinkage, and the Tg is lowered. When the temperature is as high as 30 ° C. or more, characteristics such as improvement of chemical resistance, water resistance, and reinforcing property of the base material arise.

The above-mentioned silyl group-containing vinyl polymer is obtained, for example, by copolymerization of a vinyl monomer and a hydrolyzable silyl group-containing monomer (hereinafter also referred to as a silyl group-containing monomer). The polymer may be polymerized so as to include a segment formed by a urethane bond or a siloxane bond in a part of the side chain.

The vinyl monomer is not particularly limited, and specific examples thereof include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl ( (Meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, polycarboxylic acid (maleic acid, fumaric acid, itaconic acid, etc.) and carbon number 1 Esters of unsaturated carboxylic acids such as diesters or half-esters with up to 20 linear or branched alcohols; styrene, α-methylstyrene, chlorostyrene, styrenesulfonic acid, 4-hydroxystyrene, vinyltoluene, etc. Aromatic hydrocarbon-based vinyl compounds; vinyl esters and allyl compounds such as vinyl acetate, vinyl propionate and diallyl phthalate; vinyl compounds containing nitrile groups such as (meth) acrylonitrile; vinyl compounds containing epoxy groups such as glycidyl (meth) acrylate; Amino group-containing vinyl compounds such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, vinylpyridine and aminoethyl vinyl ether; (meth) acrylamide, itaconic diamide, α-ethylacrylamide, methacrylamide, crotonamide, and maleic Acid diamide, fumaric acid diamide, N-vinylpyrrolidone, N-butoxymethyl (meth) acrylamide, N, N-dimethylacrylamide, N-methylacrylamide, acrylo Amide group-containing vinyl compounds such as rumorpholine; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl vinyl ether, N-methylol (meth) acrylamide, Alonix 5700 (Toa Gosei Chemical Industry Co., Ltd. )), Pla
ccel FA-1, Placel FA-4, Pl
hydroxyl-containing vinyl compounds such as accel FM-1 and Placel FM-4 (manufactured by Daicel Chemical Industries, Ltd.); (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, and salts thereof (alkali metal salts, ammonium salts) , Amine salts, etc.), unsaturated carboxylic acids such as maleic anhydride, acid anhydrides or salts thereof; vinyl methyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene, butadiene, isoprene, maleimide, N-vinylimidazole, vinyl sulfone And other vinyl compounds such as acids.

For example, when producing a silyl group-containing vinyl polymer having a low Tg such as 10 ° C. or lower, vinyl monomers such as butyl acrylate and 2-ethylhexyl (meth) acrylate are used. It is sufficient to use many vinyl monomers having a low Tg of the homopolymer, and when producing a high Tg having a Tg of 30 ° C. or more, the homopolymer such as methyl methacrylate, ethyl methacrylate, and styrene may be used. What is necessary is just to use many vinyl monomers with high Tg of a polymer.

The silyl group-containing monomer is not particularly limited, but specific examples thereof include, for example,

[0020]

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[0021]

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And the like.

The method for producing a silyl group-containing vinyl polymer from the silyl group-containing monomer and the vinyl monomer is not particularly limited.
No. 5, No. 57-36109, No. 58-157
No. 810, the solution polymerization using an azo radical initiator such as azobisisobutyronitrile facilitates handling of the initiator, and the polymerization reaction mixture is used as it is. Most preferred in terms of availability.

In the above production, n-dodecyl mercaptan, t-dodecyl mercaptan, n-butyl mercaptan, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, if necessary,
γ-mercaptopropylmethyldimethoxysilane, γ-
Mercaptopropylmethyldiethoxysilane, (CH ₃
O) ₃ Si—S—S—Si (OCH ₃ ) ₃ , (CH ₃ O) ₃
It is possible to adjust the molecular weight using a chain transfer agent such as _{Si-S 8 -S-Si (} OCH 3) 3.

In particular, when a chain transfer agent having a hydrolyzable silyl group in the molecule, for example, γ-mercaptopropyltrimethoxysilane, a hydrolyzable silyl group can be introduced into the terminal of the silyl group-containing vinyl polymer. .

Examples of the polymerization solvent include hydrocarbons (toluene, xylene, n-hexane, cyclohexane, etc.),
Acetates (eg, ethyl acetate, butyl acetate), alcohols (eg, methanol, ethanol, isopropanol, n-butanol), ethers (eg, ethyl cellosolve, butyl cellosolve, cellosolve acetate), ketones (methyl ethyl ketone, ethyl acetoacetate, acetylacetone) And non-reactive solvents such as diacetone alcohol, methyl isobutyl ketone, and acetone.

[0027] Other components of the underlying composition of the primer of the present invention, an organic tin compound which is a curing catalyst for the silyl group-containing vinyl polymer is used. The organic scan
To use's compound, the curing of the silyl group-containing vinyl polymer is promoted as compared to not using. In particular, even at a low temperature such as about 5 ° C. in winter, the curing is promoted, the crosslinking is easily formed, and the remarkable effect that the physical properties as a primer are rapidly exhibited is obtained.

[0028] Examples of the organic tin compounds, for example dibutyltin dilaurate, dibutyltin maleate, dioctyltin dilaurate, dioctyltin maleate, etc. tin octylate and the like. this
Al may be used alone or in combination of two or more.

In the present invention, the silyl group-containing vinyl polymer , the organotin compound as a curing catalyst and
A silicon-containing group bonded to a hydrolyzable group
The base composition of the primer of the invention is prepared from at least one amine .

[0030] Silyl group-containing vinyl in the composition
Polymers and curing catalystsIs an organotin compoundMixing ratio with
IsOrganotin compoundsAlso depends on the type of
Is not specified, but hydrolyzable silyl group-containing vinyl
Usually 0.0 for 100 parts (by weight, the same applies hereinafter)
It is about 1 to 20 parts, preferably about 0.01 to 10 parts.

Further, the vinyl polymer containing a silyl group is
and a silyl group-containing vinyl polymer having a Tg of not more than
When prepared to contain a silyl group-containing vinyl polymer having a Tg of 10 ° C. or lower, particularly when applied to a porous inorganic base material such as ALC. Is preferable for improving characteristics such as low shrinkage, and a silyl group-containing vinyl polymer having a Tg of 30 ° C. or more is effective for improving reinforcing properties and water resistance, and is therefore preferable.

In this case, the use ratio of the silyl group-containing vinyl polymer having a Tg of 10 ° C. or lower to the silyl group-containing vinyl polymer having a Tg of 30 ° C. or higher is preferably about 1/9 to 8/2 by weight ratio.

Tg can be calculated by the following Fox equation.

[0034]

(Equation 1)

(In the formula, Tgi represents the Tg of the i component, and mi represents the weight fraction of the i component.) The vinyl polymer containing a silyl group , the organotin compound as a curing catalyst , and
Minimize silicon-containing groups bonded to water-decomposable groups in the molecule
There is no particular limitation on the method for preparing a composition comprising an amine having one compound, and these may be prepared by mixing them according to a conventional method. At this time, if necessary, hydrocarbons such as toluene and xylene; acetates such as butyl acetate; alcohols such as methanol and isopropanol; other ethers; and solvents such as ketones may be used.

The above composition may or may not contain a dehydrating agent. However, a dehydrating agent is blended in order to ensure stability that does not cause a problem even when used repeatedly and long-term stability. More preferred.

Specific examples of such a dehydrating agent include, for example, methyl orthoformate, ethyl orthoformate, methyl orthoacetate, ethyl orthoacetate, methyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane,
Hydrolyzable ester compounds such as vinyltrimethoxysilane, methyl silicate, and ethyl silicate are exemplified.

In the above description, the hydrolyzable ester compound is added at the time of preparing the composition. However, it may be added before the polymerization of the silyl group-containing vinyl polymer and also used as a solvent. And may be added when the primer of the present invention is prepared using this composition.

In the above composition, 1
Amines having a silicon-containing group attached to at least one hydrolyzable group in the molecule (hereinafter also referred to as a silyl group-containing amine) of one or more is Ru is the additional inclusion. In order to contain the silyl group-containing amines, there can be obtained effects adhesiveness is remarkably improved even when for example the primers of the present invention is applied to an inorganic substrate having a dense surface as cement extruded board .

Specific examples of the silyl group-containing amine include, for example, γ-aminopropyltriethoxysilane,
a silane coupling agent such as γ-aminopropyltrimethoxysilane and N-β-aminoethyl-γ-aminopropyltrimethoxysilane; a silane coupling agent containing the amino group and ethylene oxide, butylene oxide,
Epichlorohydrin, epoxidized soybean oil, Epicort 828, Epicort 100 manufactured by Yuka Shell Epoxy Co., Ltd.
And a reaction product with an epoxy group-containing compound such as 1.

The amount of the silyl group-containing amine to be used is 1 to 100 parts of the silyl group-containing vinyl polymer.
About 500 parts are preferable, and about 5 to 200 parts is more preferable.

When the silyl group-containing amine is used in combination with the silyl group-containing vinyl polymer, when an alkyl alcohol having 1 to 4 carbon atoms is added, the composition in a container may be used repeatedly or for a long time. It is effective in stabilizing and preventing thickening and curing during storage. Specific examples of the alkyl alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol and sec-butanol. The amount of the alkyl alcohol to be used is preferably about 1 to 200 parts, more preferably about 5 to 100 parts, per 100 parts of the silyl group-containing amine.

In the above description, the silyl group-containing amine is blended at the time of preparing the composition, but it goes without saying that it may be blended at the time of preparing the primer of the present invention.

The composition used in the present invention prepared as described above generally has a resin concentration and a solution viscosity or a diluent viscosity suitable for a usual coating method, for example, brush coating or spray coating.

The primer of the present invention may be composed of only the above-mentioned composition. However, depending on the use, additives such as various pigments, dyes, anti-settling agents, leveling agents and the like; nitrocellulose, cellulose acetate butyrate, etc. Cellulose; alkyd resin, acrylic resin, vinyl chloride resin,
It may be prepared by adding a resin such as chlorinated propylene resin, chlorinated rubber and polyvinyl butyral. In particular, the addition of a pigment is effective in discriminating a portion coated with a primer.

For example, when the primer of the present invention is used as a primer for ALC, Tg is 10 ° C.
The ratio of the following silyl group-containing vinyl polymer and the silyl group-containing polymer having a Tg of 30 ° C. or more is 1/9 to 8/2 by weight ratio.
A primer blended to a certain degree is used as a base resin, and a primer such as a pigment colored with titanium oxide or the like is preferred from the viewpoint of improving the balance between low shrinkage, water resistance, and substrate reinforcement. When used as a primer for a cement extruded board, a silyl group-containing vinyl polymer 1
5 parts to 200 parts of a silyl group-containing amine are added to 00 parts, and the alkyl alcohol having 1 to 4 carbon atoms is added to
A primer prepared by adding 100 parts and coloring with titanium oxide or the like is preferred from the viewpoints of good adhesion to a substrate and good stability of viscosity during storage.

The primer of the present invention thus prepared generally has a resin solid content concentration suitable for a general coating method such as brush coating or spray coating, and a property of having a solution viscosity or a diluent viscosity. However, since these characteristics also vary depending on the type, amount, use, and the like of the components to be contained, it goes without saying that the characteristics may be out of the above range.

As described above, the primer of the present invention is coated on a porous inorganic substrate, and the water absorption of the porous inorganic substrate can be adjusted.

Since the primer of the present invention is based on a silyl group-containing vinyl polymer, the hydrolyzable silyl groups present in the polymer are hydrolyzed by moisture to form SiOH groups, and the porous inorganic substrate Because a strong bond is generated by reacting with the SiOH group present on the surface,
For example, the adhesiveness is good even for a dense material such as a cement extruded plate. In addition, since the hydrolysis of the hydrolyzable silyl group and the subsequent formation of siloxane bonds occur even at a low temperature such as about 5 ° C. in winter, for example, it cannot be used at a low temperature in a conventional epoxy primer. Is eliminated. Furthermore, since the main chain of the silyl group-containing vinyl polymer is composed of a soft main chain as compared to the epoxy resin, which is a vinyl polymer chain, even if it is applied to a porous and fragile surface such as ALC, the epoxy resin may be used. There is no problem such as in the case of a primer.

Specific examples of the porous inorganic substrate include:
For example, concrete, mortar, ALC, cellular concrete, brick, tile, slate, calcium silicate board, ceramics, tile, stone, wood chip cement board, cement extruded board, slag, gypsum cement board and the like can be mentioned.

The coating method of the primer of the present invention is not particularly limited, and the amount of the coating varies depending on the density, water absorption, etc. of the surface of the porous inorganic base material to be coated, the composition of the primer and the like, and cannot be specified unconditionally. However, for a substrate having a dense surface such as a cement extrusion molded plate, the solid content is generally about 10 to 100 g / m ² , and for a substrate having a porous surface such as ALC, the solid content is generally 50 to 200 g / m ^2.
It is about.

As described above, the porous inorganic base material coated with the primer of the present invention has excellent chemical resistance, reinforcing property, water resistance or adhesion to a topcoat material, and has excellent long-term durability. It can be suitably used as a material.

Next, the primer of the present invention will be described based on examples.

Synthesis Examples 1 to 3 360 g of xylene was charged into a reactor equipped with a stirrer, thermometer, nitrogen inlet tube, dropping funnel and cooling tube.
Heated. After that, 295 g of butyl acrylate,
579 g of methyl methacrylate, 117 g of γ-methacryloxypropyltrimethoxysilane, acrylamide 9
g and a solution of 8.5 g of azobisisobutyronitrile were continuously added to the reactor over 3 hours. After the addition of the monomer is completed, separately prepared azobisisobutyronitrile 2
g and a solution of 140 g of toluene were further added over 1 hour, and after 1 hour, polymerization was carried out to obtain a solution of a silyl group-containing vinyl resin (a-1).

The obtained resin solution has a nonvolatile concentration of 63%.
Met. The number average molecular weight of the resin measured by GPC was 15,000. PW of silyl group-containing vinyl resin
Titanium oxide (CR-90 manufactured by Ishihara Sangyo Co., Ltd.) was dispersed so as to have a C5% and a paint solid content concentration of 50% to prepare a white enamel. Dispersion was performed for 2 hours with a paint shaker using glass beads.

On the other hand, two kinds of hydrolyzable silyl group-containing vinyl resins were used in the same manner as in the above (Synthesis Example 1) except that the proportions of the monomer and azobisisobutyronitrile were changed as shown in Table 1. The solutions of (a-2) and (a-3) were obtained to prepare white enamel.

[0057]

[Table 1]

Synthesis Example 4 100 g of xylene, 80 g of methanol, and 56 g of Epicoat 828 (bisphenol A type epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd.) were placed in a reactor equipped with a stirrer, thermometer, nitrogen introduction tube, and cooling tube. , A1100 (γ-aminopropyltriethoxysilane manufactured by Nippon Unicar Co., Ltd.) 6
4 g were charged and reacted at room temperature for 30 minutes and then at 70 ° C. for 2 hours to obtain a silyl group-containing amine solution (a-4). (A-4) shows a reaction solution containing methanol or xylene.

When the obtained reaction product was analyzed by infrared spectroscopy, the absorption of the epoxy group at 910 cm ^-1 had disappeared.

Reference Examples 1 to 4 and Comparative Example 1 Dioctyltin maleate is described in Table 2 in 10 parts of the white enamel obtained in Synthesis Examples 1 to 3 on a mortar plate prepared using standard sand of JIS R5201. And the commercially available epoxy-based primer were each coated so that the thickness after drying became about 10 μm, and immediately cured at 5 ° C. Two hours later, the coated sample was completely immersed in water, stored at 5 ° C. for one day, and visually observed for any change in appearance. Table 2 shows the results.

[0061]

Reference Examples 5 to 9 and Comparative Example 2 An ALC plate (manufactured by Nippon Test Panel Industry Co., Ltd.)
The primers shown in Table 3 were applied to a thickness of about 10 μm after drying, allowed to stand at room temperature for 7 days, and then completely immersed in water. Was visually observed, and the number of cycles in which an abnormality occurred and the weight change rate after 5 cycles were measured. Table 3 shows the results.

The freeze-thaw test was performed at -20 ° C. for 3 hours for 60 hours.
The cycle was performed at 3 ° C. for 3 hours.

[0064]

[0065] Examples 1-2, Reference Examples 10-11 and Comparative Example 3 Extrusion cement board (Co. Nozawa trade name ASRock)
The primer having the composition shown in Table 4 has a thickness of about 1 after drying.
It was applied so as to be 0 μm, and allowed to stand at room temperature for 7 days. Then, the sample was completely immersed in water. The number of cycles in which these occurred was determined. At the end of 50 cycles, an adhesion test was performed. Table 4 shows the results.

A1120 in Table 4 is N-β-aminoethyl-γ-aminopropyltrimethoxysilane. In addition, the adhesion was evaluated by a cellophane tape peeling method using a 1 mm goban.

[0067]

[0068]

When the primer of the present invention is used, the disadvantage of using a conventional epoxy primer is A.
When applied to a porous and fragile surface such as LC, the coating film tends to crack and has poor durability, and insufficient adhesion to dense surfaces such as extruded cement plates. And the disadvantage that it cannot be used at low temperatures can be eliminated.

Claims (5)

(57) [Claims] 1. Silyl having a main chain substantially consisting of a vinyl polymer chain and having at least one silicon-containing group bonded to a hydrolyzable group at a terminal and / or a side chain per molecule. Group-containing vinyl polymer (provided that the main chain is substantially
Consisting of a vinyl polymer chain at the terminal and / or side
A silicon-containing group bonded to a hydrolyzable group in a chain in one molecule
Has at least one glass transition point (Tg) of 10 ° C or less
The lower silyl group-containing vinyl polymer and the main chain are substantially
Consisting of vinyl polymer chains, terminal and / or side chains
A silicon-containing group bonded to a hydrolyzable group
Has at least one glass transition point (Tg) of 30 ° C or higher
Excluding the case with a silyl group-containing vinyl polymer
A) a non-aqueous porous inorganic group based on a composition comprising (B) an amine having at least one silicon-containing group bonded to a hydrolyzable group in a molecule and (C) an organotin compound as a curing catalyst. Primer for materials. 2. A primer according to claim 1 Symbol mounting comprises an alkyl alcohol having 1 to 4 carbon atoms. 3. A primer according to claim 1 or 2 wherein a pigment. 4. A primer according to claim 1, 2 or 3, wherein the porous inorganic substrate is ALC. 5. The primer of claim 1, 2 or 3, wherein the porous inorganic substrate is a cement extruded board.