JPS6183690A - Surface treating agent for porous inorganic material - 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 The present invention relates to a surface treatment agent for porous inorganic materials such as cement-based, silicate-based, and gypsum-based materials. More specifically, the present invention relates to a surface treatment agent for porous inorganic materials having excellent performance, which is characterized by being made of a specific polyvinyl alcohol polymer containing a reactive silicon group at the end.

Traditionally, urethane resins, epoxy resins, and chloride resins have been used to protect the surface of porous inorganic materials and to improve adhesion with top coat paints and between porous inorganic materials. Organic solvent-based surface treatment agents such as vinyl/L/resin type surface treatment agents and water-based emulsion type surface treatment agents are used.

(While the invention C1 is trying to solve four points, organic solvent-based surface treatment agents use organic solvents, so there are safety and health problems, and in strongly alkaline porous materials, the resin decomposes or changes in quality for a long period of time.) There were drawbacks such as difficulty in maintaining peeling resistance over a long period of time.

Furthermore, although water-based emulsion type surface treatment agents have the advantage of not using any organic solvents, they have the disadvantage that the emulsion resin is decomposed or altered by the alkaline components in the inorganic materials, resulting in extremely low peel resistance from the inorganic materials. there were.

In addition, when trying to protect the surface of porous inorganic materials with rough and brittle surfaces or bond them to other materials, conventional surface treatment agents do not penetrate sufficiently into the inorganic materials, so In many cases, the layer cannot be consolidated, or conversely, the amount of surface treatment agent remaining on the surface is small because it penetrates too much into the inorganic material, resulting in insufficient surface protection and Adhesion with the product was insufficient.

Cum excretion gourmet first fu-Sen JJL! As a result of intensive studies to overcome the above-mentioned drawbacks, the inventors of the present invention found that a polyvinyl alcohol-based compound having a reactive silicon group at its terminal (hereinafter sometimes abbreviated as silicon-terminated PVA) When a surface treatment agent is used, the surface treatment agent has excellent alkali resistance, water resistance, and surface protection ability for inorganic materials, has a high waterproofing and water-stopping effect on inorganic materials, and has excellent contact with pond materials. The present invention has been completed based on the discovery that the following can be obtained.

As the silicon-terminated PVA used in the present invention, the following CD
It includes all PVA-based polymers containing a reactive silicon group obtained by hydrolyzing a silyl group represented by the formula.

-S' i -(Run [However, R1 is a hydrocarbon group having 1 to 20 carbon atoms, more preferably a hydrocarbon group having 1 to 10 carbon atoms, R21-1:
y an alkoxy group, phenoxy group, alkylphenoxy group, or acyloxy group having a prime number of 1 to 20, (herein, the alkoxy group, phenoxy group, alkylphenoxy group, or acyloxy group iieg-containing substituent may be present).

), n is an integer from 1 to 3. ] In this case, n is preferably 3 or 2, and 3 is particularly preferred because of the high reactivity of the silicon group.

By hydrolyzing the above-mentioned silyl group with only alkali, acid, or water, alkoxy, acyloxy, phenoxy, and alkylphenoxy groups can be relatively easily converted to OH group, OM (M is an alkali metal, ammonium group, etc.) This results in a reactive silicon group. Although there are no particular restrictions on the bond between the PVA main chain and the silicon group, it is desirable that the bond be a group that is difficult to decompose by hydrolysis or heating.

The silicon-terminated PVA of the present invention has vinyl alcohol units (-
This includes all water-soluble polymers H containing CH2-CH-). Note that the term "water-soluble" as used in the present invention includes not only those that completely dissolve in water but also those that are water-dispersible and can be dispersed in water although they contain some insoluble matter. However, in order to exhibit the effects of the present invention more efficiently, it is desirable to use a polymer containing 50 mol% or more of vinyl alcohol units.

There are no particular restrictions on component units other than vinyl alcohol units. Examples include vinyl ester units, olefin units such as ethylene and propylene, vinyl units such as acrylic acid, methacrylic acid, or salts thereof, amides, and ethers.

Various degrees of polymerization can be used for the silicon-terminated PVA of the present invention. However, porosity; the improvement in surface strength due to penetration into the material is a polymerization degree of 1000 or less, [the limiting viscosity of the aqueous solution [η] is n1il = 17 at 3o0C, and the polymerization degree determined by the Sakurada formula (Sakurada formula: preferred However, if the degree of polymerization is too low, the efficiency of crosslinking will decrease, which is undesirable, and the degree of polymerization 2 is preferably 50 or more.

The method for producing the silicon-terminated PVA of the present invention is not limited as long as it can yield PVA in which a silicon group obtained by hydrolyzing a silyl group is introduced at the end of the molecule.

For example, vinyl esters such as vinyl acetate are radically polymerized in the coexistence of a thiol compound containing a silyl group that provides the silicon group of the present invention by hydrolysis, and a polyvinyl ester such as polyvinyl acetate having a silyl group at the terminal end is obtained. l
/, saponifying the vinyl ester unit and simultaneously saponifying the vinyl ester unit! Polyvinyl esters such as polyvinyl acetate obtained by hydrolyzing J/L4 or radical polymerization of vinyl diZ-thyl compounds such as vinyl acetate in the coexistence of 1000 acetic acid.
As seen in K., PVA having an H8 group at the end is subjected to an addition reaction with a vinyl monomer having a silyl group, such as vinyltrimethoxysilane, γ-methacryloxyfuroyltrimethoxysilane, etc., to form a methoxysilyl group. It can also be produced by hydrolysis to form a reactive silicon group.

The former manufacturing method is particularly preferred because it is simple, but
) In order to efficiently introduce groups, it is necessary to
It is desirable to keep the concentration of the thiol compound containing 7 groups relative to the vinyl ester monomer as constant as possible. Since the chain transfer constant of the thiol compound is large,
For example, the thiol compound and the vinyl ester monomer ta
If the thiol compound is combined and subjected to batch polymerization without post-adding the thiol compound, the thiol compound will be rapidly consumed and run out, and as the polymerization system progresses, a large amount of polyvinyl ester that does not contain a silyl group at the end will be produced as a by-product. Therefore, PVA obtained by saponifying this is not preferable because it cannot be replaced by PVA L in which a large amount of PVA which does not have a silicon group at the end is mixed.

Therefore, PV with efficiently introduced reactive silicon groups at the end
In order to obtain A, it is preferable to replenish the silica/I/group-containing thiol compound consumed during polymerization by post-addition and to maintain the C degree e relative to the vinyl ester monomer constant.

Furthermore, a method in which a certain amount of the thiol compound and vinyl ester are continuously supplied to the polymerization tank using a continuous polymerization method and the polymerization bath solution is continuously and continuously removed can also maintain the thiol concentration in the polymerization system at a constant level. This is preferable because it allows efficient introduction of a cylindrical (IJ) group at the terminal.

As for the thiol compound having a group at the terminal, HS group and (R')! -n (R is a hydrocarbon group having 1 to 20 carbon atoms, more preferably a hydrocarbon group having 1 to 10 carbon atoms, R2 is an alkoxy group having 1 to 20 carbon atoms, a phenoxy group, an alkylpheno group) ), n is an integer of 1 to 3].

For example, 3-( )rimethoxysilyl)-probilme
Le Kabutan, 3-(1-Reet Ki
)propylmercaptan, 2-(dimethoxysilyl)ethylmercaptan, 3-(dimethoxy-methylsilyl)-propylmercaptan, 3-(
Monomethquine-dimethylsilyl)-propylmercaf”
Tan et al.

Polymerization of vinyl esters is carried out using conventional radical polymerization initiators. During polymerization, a suitable solvent can be used for the purpose of lowering the viscosity of the polymerization system. Polymerization temperature and time can be selected as appropriate. After the completion of polymerization, the residual unpolymerized vinyl ester monomer is separated and removed, and the obtained polyvinyl ester having a terminal nisilyl group is saponified by a conventional method. is preferred.

The degree of saponification at the vinylester/I/illi position can be controlled by appropriately selecting saponification conditions such as the amount of catalyst, saponification time, and temperature.

During this saponification reaction or when dissolving or dispersing the obtained polymer in water, the R
2 is mostly hydrolyzed, iS i -(R2)n (R')3-n iS i -(OM). (M is hydrogen, an alkali metal, an ammonium group, etc.), and PVA having a reactive silicon group at the terminal of the present invention can be obtained.

During the polymerization of vinyl ester, copolymerizable unsaturated monomers are copolymerized and saponified to form silicon-terminated silicon P.
A VA copolymer can be obtained. For example, ethylene
Olefins such as propylene, butylene, α-hexene,
Unsaturated acids such as (meth)acrylic acid, crotonic acid, (anhydrous)maleic acid, fumaric acid, and itaconic acid, and their alkali esters, alkali 4, (meth)acrylamide,
Sulfonic acid-containing monomers such as N,N,-dimethylacrylamide, alkyl vinyl ether, 2-acrylamide-2 to methylpropane-nurphonic acid and their a/rekali salts, trimethyl-2-(l-(meth)acrylamide-1)
, 1-dimethylethyl) ammonium chloride and the like.

Furthermore, it is also possible to copolymerize a small amount of a silyl group-containing unsaturated monomer such as vinyltrimethoxysilane or arifletriethoxysilane4, but in this case it is preferable to keep the amount within a range that does not impede the gist of the present invention. In the method of copolymerizing a silyl group-containing unsaturated monomer and introducing a silyl group into the main chain, the introduction of silyl groups is carried out randomly, so the content of silyl groups intermolecularly increases. Due to non-uniformity, a polymer component having a larger amount of silicon groups introduced than the average introduction amount is produced as saponified PVA. As a result, PVA containing a large number of silicon groups at its terminal ends and main chain also generates many reactive crosslinks between the silicon groups, making it insoluble in water. This has the disadvantage that it is necessary to add an alkali compound such as sodium hydroxide that decomposes the bonds formed by the reaction between silicon groups, so the number of silyl groups introduced by copolymerization must be small enough to not become insoluble in water. preferable.

A major feature of the PVA of the present invention having silicon groups only at the terminals is that it can be dissolved only in water, which is significantly different from those in which a silicon group component is introduced into the molecular chain by copolymerization. The difference between the two can be considered as follows. In the silicon-terminated PVA of the present invention, the reaction is mainly between the reactive silicon groups and the hydroxyl groups of PVA, and there is little reaction between the silicon groups, so the crosslinks due to the silicon groups are relatively easily decomposed and dissolved in water. It is thought that the silicon groups in the copolymer have the disadvantage of being difficult to dissolve in water, since there are many reactions between the silicon groups and they are difficult to decompose even in water.

In addition, it is thought that PVA, which contains many reactive silicon groups in its molecules, increases the reaction of the silicon groups with ions or oxides and hydrates of AJ, CaSMg, Si, etc. in inorganic materials. However, the P near the surface of the inorganic material
``V'A reacts quickly, which impairs its penetration into the inorganic material, which is undesirable.

The advantage of introducing a silicon group at the end is that the silicon group introduction site can be made uniform, and it is possible to uniformly introduce silicon groups into the molecule.
Since it does not contain A, it has the characteristics of moderate permeability into the inorganic material and easy formation of a film on the inorganic surface.

Examples of porous inorganic materials to which the surface treatment agent of the present invention is applied include cement-based, calcium silicate-based, stone-based sand, and
The main components are inorganic materials such as lightweight concrete, pre-cast concrete, ALC, mortar, cement board, and calcium silicate. Boards, pulp cement boards, wood wool cement boards, gypsum boards, hardboards, plasterboards, gypsum plasters, dolomite plasters, hard plasters, sand, clay plasters, etc. The silicon-terminated PVA of the present invention can be used after being dispersed in water. A uniform aqueous solution can be obtained by heating the mixture while stirring.

The surface treatment agent for porous inorganic materials of the present invention can be prepared by dissolving silicon-terminated PVA in water, but in this case, the concentration of silicon-terminated PVA cannot be finely adjusted in consideration of workability. 1-30% by weight, preferably 5-20%
Used within the range of % by weight.

Pigments, dyes, synthetic resin emulsions, and the like may be added to the surface treatment agent as required. The above-mentioned synthetic resin emulsions include emulsions of vinyl acetate alone or copolymers with ethylene, acrylic esters, vinyl chloride, etc., homopolymer emulsions of acrylic esters and vinyl chloride, and styrene-butadiene copolymer emulsions. Various types can be used.

The inorganic material can be coated by any of the usual methods such as brushing, spraying, roller coating, and dipping. The applied soybean has a dry solid content of 0.5 to 300 fj
/rrL2 is preferred, and although room temperature is sufficient for drying, heating drying is also possible.

(E1 action and - day present invention is a surface treatment agent for porous inorganic materials made of PVA having a specific reactive silicon group at the terminal, and has appropriate permeability into the inorganic material and reactivity of the silicon group at the terminal. As a result, it has excellent alkali resistance, water resistance, and adhesive properties, and has unique effects such as surface protection and waterproofing of porous inorganic materials, and excellent adhesion with other materials and between porous inorganic materials. Moreover, since the surface treatment agent is water-based, there is no problem in terms of safety and hygiene, and its use as an industrial material is extremely high.

The surface treatment agent for porous inorganic materials of the present invention has alkali resistance, iI! lt water-based, surface protection, waterproof, contact! Although the reason for the excellent properties, etc., has not been fully elucidated, it is thought to be due to the unique reactivity of the terminal silicon group of the present invention. That is, the silicon-terminated PVA of the present invention moderately penetrates into the porous inorganic material, and the terminal silicon groups are present in the inorganic material.
, Mg, Si, and other ions and their oxides or their hydrates to form strong bonds, and the hydroxyl groups of vinyl alcohol or the terminal silicon groups are bonded to each other, and the PVA aqueous solution When forming a film by drying, it has the property of easily reacting even under alkaline conditions to form a cross-linked product. This is thought to be due to the formation of a thick film.

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited by these examples. In addition, in the examples, F%J and "part J represent oysters'9 weight basis unless otherwise stated1. (a) Example of preparation of silicon-terminated PVA] Stirrer, thermometer, nitrogen gas introduction pipe In a reaction vessel equipped with a reflux condenser and a thiol compound addition device, 2,400 parts of vinyl monoacetate and 500 parts of methano-A were charged, and after replacing the system with nitrogen (without stirring), the internal temperature was lowered. The temperature was raised to 60°C.To this thread, 2.4 parts of 3-()!Jmethoxysilyl)propylmercaptan was added (referred to as the initial addition of thiol), and further 2.2'-azobisisobutylene was added. 0.87 parts of lonitrile in methanol/L/100
Polymerization was started by adding the solution dissolved in 1 part. 3-()rimethoxysilyl) continuously for 3 hours after the start of polymerization
80 parts of a methanol solution containing 27 parts of probilmercaf (hereinafter referred to as post-addition of thiol) was added. After continuing the polymerization for 3 hours, the polymerization was stopped.

At this point, the solid content concentration in the system was 40.9% (polymerization rate 51.0%).

After expelling unreacted vinyl acetate by introducing methanol vapor, a 40% methanol solution of polyvinyl acetate having a silyl group at the end was obtained.

While stirring the methanol solution of this polymer at 40°C,
A methanol solution containing 5 mol % of sodium hydroxide dissolved in vinyl acetate units was added to this solution to carry out a saponification reaction. The resulting white gel is crushed, thoroughly washed with methanol, and then dried to form PVA with silicon groups at the ends.
I got it. The obtained PVA had a polymerization degree of 216 (calculated using Sakurada's formula) and a saponification degree of vinyl acetate units of 99.2 mol%.

Examples 2 to 5 Type of silyl group-containing thiol, initial amount of thiol added,
Various degrees of polymerization,
PVA having a silicon group at the end of the degree of saponification was obtained. Table 1 summarizes the name of the thiol used, the initial addition amount of thiol, the subsequent addition amount of thiol, the degree of polymerization, and the degree of saponification of the obtained PVA.

Comparative Examples 1 to 5 Comparative examples 1 to 5 were prepared in the same manner as in Example 1, except that 2-nuricafotethanol was used in place of 3-(trimethoxysilyl)fluoroylmercabutane in Example, which did not have a silicon group at the end. PVA was obtained.Table 1 shows the amount of 2-mercaptoethanol used and the degree of polymerization and saponification of PVA.

1 Comparative Example 5i Same as above lO,03□′0.3
4 11710 99.0 (b) Application test on porous inorganic materials Example 6 A 5% aqueous solution of silicon-terminated PVA obtained in Example 1 was prepared, and an asbestos slate plate with a surface pH of 1O and an asbestos slate plate with a surface pH of] Apply it to the mortar plate in Step 2 so that the dry solid content is 50y/rrL, and put cotton cloth on top of it as a reinforcing agent.
Dry at room temperature for several days. After that, cut the ffA film on the asbestos slate with a knife to the width of α, immerse it in water at room temperature for 3 days, and peel it off with an autoclave (Shimadzu IM-100 model) at an angle of 9.
The water-resistant adhesive strength was measured at 0° and a tensile speed of 500 wm/min, and the results shown in Table 2 were obtained.

Example 7 to 0 Using the silicon-terminated PVA obtained in Examples 2 to 5, water-resistant adhesion tests to asbestos slate boards and mortar boards were carried out in the same manner as in Example 6. The results are shown in Table 2.

Comparative Example 6-]0 Using the PVA obtained in Comparative Examples 1-5, tests for water-resistant adhesion to a high-height slate board and a mortar board were carried out in the same manner as in Example 6. The results are shown in Table 2.

Comparative Example 11 Using a vinyl acetate polymer emulsion containing 8% of unmodified PV polymer as a protective colloid with a degree of saponification of 88 mol% and a 4% aqueous solution having a viscosity of 23 cp at 20°C, Example 6
Water resistant adhesive strength was measured in the same manner as above. Table 2 shows the results.
Shown below.

Table 2 shows that the surface treatment agent of the present invention has extremely high water adhesion even under alkaline conditions, and is excellent in peel resistance, water resistance, and alkali resistance.

Example 11 A mortar of cement: sand: water, 10:30:8.8 was poured into a plywood formwork, left as it was for one day, then removed from the mold, and placed in KIO at a constant temperature and humidity of 20°C and 65% RH. I cured it for a day. A weak layer (latance) was formed on the surface of this mortar. 5 of silicon-terminated PVA obtained in Example 1
% aqueous solution was adjusted and applied to mortar with laitance so that the dry solid content was 17m and left for 2 days. Next, this mortar substrate was broken and a cross-section Mi K I2 aqueous solution was applied.

Since the PVA portion that had penetrated into the mortar was colored by I2, the degree of penetration of the silicon-terminated PVA into the mortar was measured using a stereoscopic microscope. The results are shown in Table 3.

Next, using a washability abrasion test bag machine (Toyo Seikishi), the wear area of 40 x 380 periods was measured using a washability abrasion test bag machine (Toyo Seiki) using the same method on the laitance mortar coated with PVA using the same method. A wear resistance test was conducted by rubbing the material twice and measuring the wear amount. The results are shown in Table 3.

A mortar of cement: sand: water, -+O: 20:6.5 was applied to the mortar containing the laitance coated with PVA, and the mixture was placed in a room at 20°C and 65% RH and in water at 20°C for 7 days. After standing, the bending strength was measured and the adhesion between the mortar base material and the mortar finish layer was examined. The results are shown in Table 3.

Example 12 Using the silicon-terminated PVA obtained in Example 3, a surface treatment test on mortar containing laitance was conducted in the same manner as in Example 1. The results are shown in Table 3.

Comparative Examples 12 to 14 Using the PVA obtained in Comparative Examples 1.4.5, a surface treatment test on mortar containing reitan and silver was conducted in the same manner as in Example 1. The results are shown in Table 3. Table 3 From Table 3, it can be seen that the surface treatment agent made of silicon-terminated PVA of the present invention has appropriate permeability to mortar with laitance, excellent wear resistance, and It can be seen that the adhesion properties when dry and when wet are extremely excellent.

Example 13 A 5% aqueous solution of the silicon-terminated PVA obtained in Example 2 was placed on a foam light concrete plate (hereinafter abbreviated as A and LC) to a dry solid content of 20%. /rat,
It was left indoors for 2 hours. After that, the solid content concentration 5 is applied to the applied surface.
After applying a 0% vinyl acetate resin emulsion in a wet coating amount of about 120y, the sample was left indoors to dry for 7 days.

After this test piece was exposed outdoors for 6 months starting in spring, cuts were made in the shape of base marks on the coated surface using a cutter knife, adhesive tape was attached and then peeled off, and each boundary between the base material, surface treatment agent, and top coat was removed. The adhesion was measured. The results and the test results of Sonoya are shown in Table 4.

Examples 14 to I6 Trials similar to those in Example 13 were conducted using a surface treatment agent made of silicon-terminated PVA and an inorganic material as shown in Table 4. The results are shown in Table 4.

Comparative Examples 5 and 16 Tests similar to those in Example 13 were conducted using surface treatment agents and inorganic materials consisting of PVA with silicon terminals and no 7 as shown in Table 4. The results are shown in Table 4.

From Table 4, it is clear that the surface treatment agent made of silicon-terminated PVA of the present invention has excellent adhesion to inorganic materials and top coats, and has excellent water resistance and alkali resistance.

Claims (3)

[Claims] (1) A surface treatment agent for porous inorganic materials characterized by being made of a polyvinyl alcohol-based polymer containing a reactive silicon group obtained by hydrolyzing a silyl group represented by the following formula [I] at the molecular end. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] [However, R^1 is a hydrocarbon group with 1 to 20 carbon atoms, R^
2 is an alkoxy group, phenoxy group, alkylphenoxy group, or acyloxy group having 1 to 20 carbon atoms (here, the alkoxy group, phenoxy group, alkylphenoxy group, and acyloxy group may have an oxygen-containing substituent. )
n is an integer of 3 to 1. ] (2) The surface treatment agent for porous inorganic materials according to claim 1, wherein the polyvinyl alcohol-based polymer containing a reactive silicon group at the terminal has a degree of polymerization of 50 or more. (3) The surface treatment agent for porous inorganic materials according to claim 1, wherein n of the silyl group of the formula [I] is 2 or more.