JPS58171457A - Coating agent for porous inorganic material - Google Patents

Abstract

PURPOSE:To provide the titled coating agent having excellent adhesivity to the top-coating paint and the finishing agent, and having excellent peeling resistance, water resistance, etc., and suitable for the coating of light-weight concrete, etc., by using a synthetic resin emulsion containing a silicon-containing modified polyvinyl alcohol as an emulsifier. CONSTITUTION:The objective coating agent is prepared by adding (A) 0.1- 20pts.wt. of an emulsifier comprising a silicon-containing modified polyvinyl alcohol obtained by mixing (i) an organic solvent inert to a silylating agent (e.g. benzene), (ii) a silylating agent (e.g. trimethylchlorosilane) and (iii) a modified polyvinyl acetate, to (B) 100pts.wt. of an ethylenic unsaturated monomer (e.g. vinyl acetate). EFFECT:Excellent alkali resistance and efflorescence resistance.

Description

Detailed Description of the Invention The present invention relates to a coating material having excellent adhesion to porous inorganic materials such as cement-based, calcium silicate-based, and gypsum-based materials. Related to coating agents for porous inorganic materials made of synthetic resin emulsions containing polyvinyl alcohol (hereinafter polyvinyl alcohol is abbreviated as PTA). For the purpose of improving adhesion with finishing agents, organic solvent-based coating materials such as urethane resin, Evo medium resin, vinyl chloride resin, vinyl acetate polymer emulsion, acrylic acid ester emulsion, and copolymerization of these are used. Aqueous emulsion shore WNI covering agents such as coalesced emulsions have been used. However, organic solution 1llII! Since coating materials use organic solvents, there are health and safety issues, and in highly alkaline porous building materials, it is important to maintain adhesive strength and peeling resistance over a long period of time due to decomposition or deterioration of the resin. There were drawbacks such as. Furthermore, although water-based emulsion type coating materials have the advantage of not using any organic solvents, they have the disadvantage of low adhesive strength and peeling resistance due to poor alkali resistance, soap resistance, and water resistance.

The inventors of the present invention have worked hard to overcome the above drawbacks! As a result, a synthetic resin emulsion obtained by post-emulsifying an ethylenically unsaturated monomer and a combined polymer in the presence of modified PVA containing silicon in the molecule can be used as a porous inorganic material. Impregnation.

The present inventors have discovered that when applied, it has high water resistance and alkali resistance, and has excellent adhesion to inorganic materials and top ah paints or finishing agents used for the inorganic materials.

Porous inorganic materials to which the coating material of the present invention is applied are those whose main components are cement-based, calcium silicate-based, gypsum-based, etc., and examples include lightweight concrete, precast concrete, lightweight concrete, etc. Aerated concrete) (ALC), mortar, asbestos cement board, calcium silicate board, pulp cement board, wood wool cement board 1 gypsum board, hardboard, plasterboard, gypsum plaster,
Examples include dolomite plaster, hard plaster, etc. The modified PVA containing silicon in the molecule used in the present invention can be produced, for example, by the following method.

017 A method for introducing silicon into modified polyvinyl acetate containing a carboxyl group or a hydroxyl group by post-modification using a silylating agent. Examples include methods for converting 'In the method of post-modifying PVA or unmodified vinyl acetate using a silylating agent, for example, an organic solvent that does not react with the silylating agent, such as benzene, toluene, xylene, hexane 1, heptane, ether or achitone, etc. Dissolve the silylating agent,
Powdered PVA or the above-mentioned modified polyvinyl acetate is suspended in a solution with stirring, and the silylation sub-base is reacted with PVA or the above-mentioned modified polyvinyl acetate at a temperature ranging from room temperature to the boiling point of the silylation agent. Silicon-containing modified PVA can be obtained by saponifying the vinyl acetate potential by oxidation or by further saponifying the vinyl acetate potential with an alkali catalyst etc. The silylation agents used in such post-modification include silane, trimethylchlorosilane, dimethyl Organohalogen silanes such as dichlorosilane, methyltrichlorosilane, vinyltrichlorosilane, diphenyldichlorosilane, and triethylfluorosilane; organosilicon esters such as trimethylacetoxysilane and dimethyldiacetoxysilane; trimethylmethoxysilane and dimethyldimethoxysilane; organoalkoxysilane,
Examples include trimethylsilanol, diethylsilanediol, a cape organosilanol, aminoalkylsilanes such as N-aminoethylaminopropyltrimethoxysilane, and organosilicon isocyanate bases such as trimethylsilicon isocyanate. The rate of introduction of the silylating agent, that is, the rate of modification, can be arbitrarily adjusted depending on the amount of the silylating agent used and the reaction time. Further, the degree of polymerization and saponification of the obtained silicon-containing modified PTA□ can be arbitrarily adjusted by the degree of polymerization and saponification of the PVA used, or the degree of polymerization and saponification of the above-mentioned modified polyvinyl acetate.

In addition, in a method for saponifying a copolymer of a vinyl ester and a silicon-containing olefinic unsaturated monomer, for example, 1, for example, ``vinyl ester and a silicon-containing olefinic unsaturated monomer are mixed in alcohol with a radical initiator. A silicon-containing modified PVA can be obtained by copolymerizing the scissors copolymer using the above-mentioned polymer, and then adding an alkali or acid catalyst to the alcohol solution of the core copolymer to saponify the scissors copolymer. Vinyl esters used in such a method include vinyl acetate, vinyl propionate, vinyl formate, etc., but vinyl acetate is preferred from an economic standpoint. On the other hand, the silicon-containing olefinically unsaturated monomer used in such a method is expressed by the following formula (1
) or (II) (
Meth)acrylamide-alkylsilanes may be mentioned.

1,000-CuS-CM・(CuS)n-81-(R2), 4
(1) υ (where n is θ~4, m is O~2%, R1 is hydrogen,
・Logen, a lower alkyl group, an allyl group, or a lower alkyl group having an allyl group, R1 is an alkoxyl group, an acyloxyl group (here, the alkoxyl group or acyloxyl group may have an oxygen-containing substituent) or hydroxyl group R8 is hydrogen or methyl group n4 is lower alkyl group,
R5 represents an alkylene group or a divalent organic residue in which chain carbon atoms are bonded to each other via oxygen) 0 As a specific example of the vinylsilane represented by formula (1), for example, tt-1'vinyltrimethoxy Silane, vinylt/' ethoxysilane, vinyltris-(β-methoxyethoxy)silane, vinyltriacetoxysilane, allyltrimethoxysilane, allyltriacetoxysilane,
Vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinylmethyljethoxysilane, vinyldimethylethoxysilane, vinylmethyldiacetoxysilane, vinyldimethylacetoxysilane, vinylisobutyldimethoxysilane, vinylmethoxydibutoxysilane,
Vinyldimethoxybutoxysilane, vinyltributoxysilane, vinyldimethoxydihexyloxysilane, vinyldimethoxyhexyloxysilane, vinyltrihexyloxysilane, vinylditoxyoctyloxysilane, vinyldimethoxyoctyloxysilane, vinyltrioctyloxysilane, Vinylmethoxydibutoxysilane, vinylmethoxydibutoxysilane, vinylmethoxydioleyloxysilane, vinyldimethoxyoctyloxysilane, represented by the general formula % (where m is the same as above and represents 1 to 2o) Examples include polyethylene glycol derivatives of vinylmethoxysilane. Also, expressed by the formula (fl) (
Specific examples of meth)acrylamide-alkylsilane include 3-(meth)acrylamide-propyltrimethoxysilane, 3-(meth)acrylamide-propyltriethoxysilane, and 3-(meth)acrylamide-propyltriethoxysilane.
Propyltri(β-methoxyethoxy)silane, 2-(
meth)acrylamide-ethyltrimethoxysilane, 1
-(meth)acrylamide-methyltrimethoxysilane, 2-(methacrylamide-2-methylpropyltrimethoxysilane, 2-(meth)acrylamide-2-
Methylglobiltriethoxysilane, 2-(meth)acrylido-isopropyltrimethoxysilane, N-(
2-(#')acrylamido-ethyl)-azunoprobyltrimethoxysilane, 3-(meth)acrylamide-
Propyltriacetoxine, 3-(meth)acrylamide-propylisobutyldimethoxysilane, 2-(
meth)acrylamide (-propyl-dimethylmethoxysilane, 2-(meth)acrylamide-ethyldimethylmethoxysilane, 3-(meth)acrylamide-propylbenzyljethoxysilane, 3-(N-methyl-(meth)acrylide) )-propyltrimethoxysilane and the like.

The alcohol used in producing the modified PTA used in the present invention includes lower alcohols such as methanol and ethanol, but methanol is preferred from an economical standpoint.

Polymerization can be carried out either batchwise or continuously, but in the case of a batchwise method, the copolymerization reactivity ratio (rttrs)
Therefore, one or both of the monomers is added continuously as the polymerization progresses, and the conditions are adjusted so that the concentration ratio of the monomers in the polymerization reaction solution is always constant throughout the polymerization period. It is preferable. How to calculate the amount added in this caseQ
-For example, RoJ, Hanna is an Industr
lml and EngineeringChem
istry, Vol, 49.42.208-209
(1957). Similarly, in the case of multi-column continuous copolymerization, it is preferable to add monomers to each group so that the monomer concentration ratio in each column is constant. As a polymerization initiator, 2,2'-azobisinbutyronitrile, benzoyl peroxide, 90yl peroxide,
Known radical polymerization initiators such as acetyl peroxide can be used. The polymerization reaction temperature is usually selected from the range of 50°C to the boiling point of the polymerization system.
In addition to the components, other unsaturations copolymerizable with the monomers, such as t-styrene, alkyl vinyl ether, vinyl versatate, (meth)acrylate, ethylene, propylene, 2-hexene, 2- Olefins such as octene, (meth)acrylic acid, crotonic acid, (anhydrous) maleic acid, hepmaric acid, unsaturated acids such as itaconic acid, and their alkyl esters, alkali salts, 2-acrylamido-2-methylpropanesulfone Sulfonic acid va-containing substances such as acids and their alkali salts, trimethyl-3-(1-
A small proportion of cationic monomers such as acrylamide-1,1-dimethylpropyl) ammonium chloride, trimethyl-3-(1-acrylamidopropyl) ammonium chloride, 1-vinyl-2-methylimidazole and its quaternized products. The amount of silicon-containing polymerizable monomer units in the copolymer may be appropriately selected depending on the purpose, but is usually selected from the range of 0.1 to 5 mol. Further, the degree of polymerization of the copolymer can be arbitrarily adjusted by adjusting the amount of alcohol used as a solvent. After the copolymerization is completed, if vinyl ester remains in the reaction solution, it must be removed by distillation or the like.

If the silicon-containing polymerizable monomer remains, it may be removed separately from the vinyl ester, or if it is left in a small amount, it will not interfere with the general purpose.

The copolymer thus obtained is then saponified. The saponification reaction is usually carried out using the copolymer as an alcohol solution.
It is advantageous to carry out the reaction after the alcoholysis. Not only anhydrous alcohols but also alcohols containing a small amount of water can be used depending on the purpose. In addition, examples of the resaponification catalyst in which Nalcol may optionally contain an organic solvent such as methyl acetate or ethyl acetate include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, sodium methylate, potassium methylate, etc. An alkaline catalyst such as alcoholade or ammonia is used;
! ! Acid catalysts such as sulfuric acid and the like can also be used. Among these catalysts, alkali catalysts are advantageous in that they have a fast saponification reaction rate, and among them, sodium hydroxide is economically advantageous from an industrial perspective.

The saponification temperature is usually selected from the range of 10 to 50°C.

The vinyl ester units are partially or highly saponified and converted into vinyl alcohol units by the saponification reaction, and this conversion rate can be set to any value depending on the intended use of the modified Pvm.

Furthermore, the vinyl alkoxysilane units are also partially saponified to a high degree and converted into vinyl silanol units or their alkali salts or their intercondensates.

The synthetic resin emulsion used in the present invention can be obtained by emulsion polymerizing ethylenically unsaturated monomers in the presence of modified PVA containing silicon in the molecule as described above, or by post-processing the synthetic resin in the presence of the modified PVA. The essential condition is that it is obtained by emulsification, and the modified PVA is simply added to the synthetic resin emulsion obtained by the later method.
The effect of the present invention cannot be sufficiently obtained by simply adding .

As mentioned above, when carrying out emulsion polymerization of an ethylenically unsaturated compound, the ethylenically unsaturated compound is added temporarily or continuously in the presence of water, a polymerization initiator, and modified PVA containing silicon in the molecule. Any conventional emulsion polymerization method such as heating and stirring can be carried out. At this time, other known emulsion stabilizers such as ordinary unmodified PVA, nonionic Surfactants, anionic surfactants, cationic surfactants, cellulose 11 conductors (carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, etc.), etc. can also be used in combination as appropriate.

In addition, various additives and regulators used in ordinary emulsion polymerization can also be used as appropriate.
The amount of O used is usually appropriately selected from the range of 0.1 to 20 parts by weight per 100 parts by weight of the ethylenically unsaturated monomer. are vinyl esters such as vinyl acetate, vinyl propionate, and vinyl versatate, which is a higher aliphatic vinyl ester, methyl (meth)acrylate,
(meth)acrylic esters such as ethyl (meth)acrylate, butyl (meth)acrylate, and octyl (meth)acrylate, or vinyl chloride, vinylidene chloride, (lfi)acrylonitrile, styrene, ethylene,
Propylene, (meth)acrylamide, N-methylol-(meth)acrylamide, maleic acid diester, fumaric acid diester, itaconic acid diester, butadiene, isoprene and the like can be used alone or as a mixture thereof.

Examples of the emulsion polymerization initiator include initiators used in ordinary emulsion polymerization, such as hydrogen peroxide, ammonium persulfate, and
A known redox system is employed using a known peroxide such as oxide, or a combination of these and a reducing agent such as sodium bisulfite, sodium pyrosulfite, or sodium formaldehyde sulfoxylate. The initiator is an olefinically unsaturated compound 10
It is used in an amount ratio of 0.01 to 5 parts by weight to 0 parts by weight.

The temperature at which emulsion polymerization is carried out may be 30 to 100°C, preferably 40 to 90°C.On the other hand, in the case where a synthetic resin is obtained by post-emulsifying a synthetic resin, silicon is added in the molecule as described above. Modified PVA containing
A method in which the modified PVA is dissolved in an organic solvent that is insoluble in water and has a relatively low boiling point, added with a synthetic resin solution, stirred and emulsified, and then the organic solvent is distilled off.
Any conventional post-emulsification method can be carried out, such as a method in which a thermoplastic synthetic resin is added to water containing a thermoplastic synthetic resin, emulsified by stirring or kneading at a high temperature above the softening point of the thermoplastic synthetic resin, and then cooled. At this time, it is possible to appropriately use other known emulsion stabilizers and the like together with the above-mentioned modified PVA containing silicon in the molecule. When obtaining a synthetic resin emulsion by the post-emulsification method, the amount of the modified PVA used is usually 0.1 to 20j1 per 10011 parts of the synthetic resin.
1. The synthetic resin used in the above method can be selected from a range of parts by weight, and may include the above-mentioned ethylenically unsaturated monomers alone or copolymers.

The coating material of the present invention can be obtained by various methods as described above. Although it is based on a synthetic resin emulsion containing silicon-containing modified PVA, the synthetic resin emulsion must contain 1! Coloring agents such as ordinary unmodified PVA, cellulose derivatives, plasticizers, pigments, and dyes may also be added to the coating material.
Used in the range of ~50 (weight), preferably 10 to 30. The coating method for inorganic building materials can be general coating methods such as spraying, spraying, roller coating, and dipping. The coating amount is preferably 10 to 300 f/r/, and drying at room temperature is sufficient, but there is no problem in drying by heating.

Building materials treated with the coating agent of the present invention have extremely good adhesion with top coats and finishing agents, and are extremely useful as industrial materials with excellent peeling resistance, water resistance, alkali resistance, and efflorescence resistance. It has high utility value.

Although the details of the reason why the coating material of the present invention exhibits the excellent performance as described above are unknown, it is presumed as follows. That is, the silicon substituent in the modified PVA containing silicon in the molecule used in the present invention easily reacts with AJ, Ca, MP, 81 fathom ions and their oxides or hydrates in inorganic building materials. In addition to forming strong bonds, the silicon capping substituents in the modified PVA also have the property of easily reacting to form a crosslinked product even under alkaline conditions when the modified PVA aqueous solution forms a film by drying. tl-, it does not penetrate into inorganic building materials indefinitely and remains in the surface layer of inorganic materials, forming a strong film with excellent water resistance even under alkaline conditions, thereby strengthening the surface layer of inorganic building materials. It is thought that peeling resistance, water resistance, efflux resistance, and adhesion to top coatings or finishing agents are significantly improved.

The present invention will be specifically explained below with reference to examples, but these examples are not meant to limit the invention in the same way. still,%
Unless otherwise specified, all parts or units are by weight.

Example 1 A copolymer of vinyltrimethoxysilane and vinyl acetate was obtained by saponifying the copolymer, containing 0.25 molar silicon as vinylsilane units, and having a degree of saponification of vinyl acetate units of 8.
Stable emulsion of silicon-containing modified PVA with a viscosity of 7.5 molar and 4-aqueous solution at 20°C (according to a Brookfield viscometer, hereinafter the same) is 30 centiboise (hereinafter centiboise is described as 6p). Emulsion polymerization of vinyl acetate as an agent was carried out as follows.

That is, 8s of the modified PVA and 85 parts of water were placed in a separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, and the mixture was stirred and heated to dissolve the modified PVA, and then cooled. Add vinyl acetate lOs, and while stirring, bring the internal temperature of the flask to 6.
The temperature was raised to 0°C. While nitrogen gas was introduced into the flask to replace the system with nitrogen, an aqueous hydrogen peroxide solution and an aqueous solution of pyrosulfite (IJ) were added as polymerization initiators to initiate polymerization. Initial polymerization was carried out for 30 minutes, and the remaining 40 parts of vinyl acetate was added dropwise over 2 hours, followed by 70°C.
After aging for 1 hour, cool. The resulting emulsion had a resin content of 40° and a viscosity at 30°C (Brookfield viscometer, rotational speed 2°r, I) of 31.0
00 centipoise (hereinafter, centipoise is abbreviated as ep).

This emulsion is dibutyl 7 as a plasticizer for 100s.
After adding 10 parts of tallate, a dry film of 2 parts was formed on a mortar plate with a surface layer of 12 and an asbestos slate plate with a surface layer of 10.
00/J (-q ichromator), and a cotton cloth was placed thereon as a reinforcing agent and air-dried for 3 days to form a film. Cut this film into a width of 1 with a cutter knife.
Cut the crn, temperature 20℃, relative humidity 65R.
) After controlling the humidity for 3 days in a constant temperature room in step 1, and then further at 20℃
After being immersed in water for 3 days, the peel strength was measured using an autograph at an angle of 90°. The results are shown in Table 1.

Example 2 A copolymer of vinyltriacetoxysilane and vinyl acetate was obtained by saponifying a copolymer of vinyl acetate, containing silicon as a vinylsilane unit and containing C03 mole, and saponifying the vinyl acetate unit f'
;The viscosity of a 91 mol 14% aqueous solution at 20°C is 27c
Emulsion polymerization of vinyl acetate was carried out as follows using silicon-containing modified PVA as emulsion stabilizer.

That is, in a separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, the above modified PvA8s and water 92
s was added, stirred and heated to dissolve the modified PVA, and then cooled. After adding and dissolving 0.185 parts of potassium persulfate, 18 parts of vinyl acetate was added, and while stirring, nitrogen gas was introduced into the flask to replace the makuuchi with nitrogen, and the internal temperature was raised to 64-65°C. After 20 minutes of initial polymerization, 32 parts of vinyl acetate was added dropwise over 2.5 hours, and the mixture was aged at 70° C. for 1 hour, and then cooled. The resulting emulsion had a resin content of 38 grams,
The viscosity at 30°C was 29,000 cp. Using this emulsion, the peel strength against mortar and asbestos slate plates was measured in the same manner as in Example 1. The results are number 1! ! ! Shown below.

Comparative Example 1 Saponification degree 88 Soruchi, 4 in place of modified PVA in Example 2
The resin content was 39.511 in the same manner as in Example 2 except that PVA with a viscosity of 22.5 ep at 20°C of the aqueous solution was used.
An emulsion with a viscosity of 20,000 Cp at 30°C was obtained. Using this emulsion, the adhesive strength to mortar and asbestos slate plates was measured in the same manner as in Example 1. The results are also shown in Table 1.

Example 3 A copolymer of vinyldimethylethoxysilane and vinyl acetate was obtained by saponifying the copolymer, containing 1 mole of silicon as a vinylsilane unit, and having a saponification degree of vinyl acetate units of 87.
Viscosity of a 5 molar, 4 molar aqueous solution at 20°C6. Sep
An ethylene-vinyl acetate emulsion copolymerization method was carried out as follows using silicon-containing modified PvA as an emulsion stabilizer.

That is, 6 parts of the modified PVA and 100 parts of distilled water were placed in a pressure-resistant reaction tank equipped with a stirrer, a temperature detection end, and a liquid charging device, and the modified PVA was dissolved by stirring and raising the temperature. After cooling, 120 parts of vinyl acetate was added to the system while stirring,
Further, ethylene gas was introduced to adjust the pressure of the system to 45 kF/-, and the temperature inside the system was raised to 60°C. At a temperature of 60"C, an aqueous hydrogen peroxide solution and an aqueous sodium pyrosulfite solution were added and emulsion polymerized for 3 hours. After the polymerization was completed, the... was adjusted to 6.0 with an ammonia aqueous solution. The obtained ethylene-vinyl acetate copolymer emulsion was The ethylene unit was 45.2 molar, the resin content was 49.5 h, and the viscosity at 30''C was 5 scp. Adhesive strength to mortar and asbestos slate board was measured in the same manner as in Example 1.

The results are also shown in Table 1.

Comparative Example 2 In place of the modified PVA of Example 3, saponification degree of 88 mol IG
, PV with a viscosity of 45 cp at 20°C in an aqueous solution of 41 m
The resin content was 50 Is in the same manner as in Example 5 except that A was used.
An emulsion was obtained with a viscosity of 79 el at 3.0°C. Using this emulsion, the adhesive strength to a mortar board and an asbestos slate board was measured in the same manner as in Example 1.
It was measured with The results are also shown in Table 1.

Table 1 1) Adhesive strength after drying the film and conditioning the humidity at 20°C and 65% RH for 3 days. The adhesive strength is Autograph (manufactured by Takasugi Seisakusho,
The test piece of 1]11 was measured at a tensile speed of 50011III10K at an angle of 90° using an IM-100 model.

2) After the film was dried, it was immersed in water at 20°C for 3 days, and immediately after being taken out, it was measured using an autograph in the same manner as in 1).

From Table 1, it can be seen that the coating material of the present invention has a high water-resistant adhesive strength even to alkaline porous inorganic building materials.

Example 4 A copolymer of vinyltriethoxysilane and vinyl acetate was obtained by saponifying the copolymer, containing 0.25 silicon as vinyl silane units, and having a degree of saponification of vinyl acetate units of 87.
Mol'II, 41G, viscosity at 20'CK of aqueous solution 6
．． Vinyl acetate-ethyl acrylate system copolymerization was carried out as follows using silicon-containing modified PVA as Sep as an emulsion stabilizer.
carried out.

That is, 450 parts of the above-mentioned modified PVA aqueous solution, 10 parts of ethyl acrylate, and 50 parts of vinyl acetate were charged into a reaction tank equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, and the mixture was uniformly emulsified. Thereafter, 41 parts of ammonium persulfate (6 hours) and 60 parts of sodium bisulfite (10 hours) were added, and the temperature in the system was raised to 60° C. to initiate polymerization. Warm! i Ethyl acrylate 55 while continuing polymerization at 60℃
Emulsion polymerization was carried out for 3 hours while adding dropwise a mixture of 275 parts of vinyl acetate and 275 parts of 2-ammonium persulfate aqueous solution. After dropping, the temperature was raised to 70°C and aged for 30 minutes.
Room! 5. Cool down to 1.5 liters and rinse with ion ammonia aqueous solution.
Adjusted to OK. The resulting nine copolymer emulsion had a resin content of 40% and a viscosity at 30'C of 100 ep. This emulsion was applied to a calcium silicate plate (Siical plate) so that the coating amount was 100 f/d, and the plate was left indoors for 2 hours. Thereafter, a vinyl acetate resin emulsion with a solid content concentration of 4091 was applied using a roller brush at a wet coating rate of about 120 f/m, and then left indoors for 7 days. After exposing this test piece outdoors for 6 months, the painted surface was cross-cut with a cutter knife.
Next, adhesion at each interface between the base material, the coating material, and the top coat film was examined using gummed tape at the cut portion. The results are shown in Table 2.

Comparative Example 3 In place of modified PVAK in Example 4, saponification degree of 88 mol.
5. Viscosity of aqueous solution at 20°C. ．． 3 (P of !p
Emulsion polymerization was carried out in the same manner as in Example 4, except that VA was used, and the adhesiveness of the obtained emulsion was measured in the same manner as in Example 4. The results are shown in Table 2. 3) Evaluation criteria ◎; Paint film does not peel off and has good adhesion ○;
Partially peeled off.
Judgment was made by observing the state of the coating film after immersion for one day.

Alkali resistance: KI test pieces in saturated lime water before outdoor exposure
Judgment was made by observing the state of the coating film after immersion for 0 days.

Q;I! No changes in condition such as blistering or discoloration of II were observed.

○; Discoloration of l is visible○ x; Severe discoloration and blistering.

Example 5 Cement: sand: gravel = 1:3:3, cement/water ratio 6
5 pieces of concrete 1 were poured into a plywood formwork, cured in a greenhouse for one day at a relative humidity of 85-95% and a temperature of 20'C, removed from the mold, and then submerged in water at 20'C for 6 days. I took care of myself. Next, the ethylene-vinyl acetate copolymer emulsion obtained in Example 3 was applied to the surface of this concrete that was in contact with the plywood formwork so that the dry solid content was 65 f/-, and after being left for day and night, A mortar with a cement/water ratio of 1:3 and a cement/water ratio of 60 was poured, and the mixture was cured in a greenhouse for one day under the above conditions, and then heated indoors (25°C, 60-7011°C).
RH) or in water at 20° C. for 7 days, the bending strength was measured and the adhesion between the concrete and the mortar finish layer was investigated. The results are shown in Table 13.

Comparative Example 4 Bending strength was measured in the same manner as in Example 5 except that the ethylene-vinyl acetate copolymer emulsion obtained in Comparative Example 2 was used instead of the emulsion in Example 5. The results are also shown in Table 3.

Table 3 5) Bending strength was measured using an Amsler type tensile tester using a bending test method using the joint between cement and mortar as a fulcrum.

It can be seen from Table 3 that the coating material of the present invention has significantly superior dry adhesive strength and wet water-resistant adhesive strength.

Example 6 Modified P containing silicon in the molecule used in Example 1
Add 100 g of vinyl nine acetate polymer resin obtained by a one-solution polymerization method to 18 parts of water containing 0 parts of VAl, and use a pressure kneader to
After kneading at 70° C. for 20 minutes, 120 parts of water was gradually added to the mixture while vigorously stirring it, and the mixture was cooled to obtain a post-emulsion emulsion (solid content: 44%) of vinyl acetate polymer.

Using this emulsion, the adhesion between concrete and the mortar finish layer was examined in the same manner as in Example 5. The bending strength after 7 days of indoor curing and underwater curing was 27, respectively.
．． 519/d, 23.6 kp/-O Patent Applicant Ri Co., Ltd. Rare Representative Patent Attorney Tate Honda

Claims (1)

[Scope of Claims] (1) A coating agent for porous inorganic materials comprising a synthetic resin emulsion containing modified polyvinyl alcohol containing silicon in the molecule as an emulsifier. (2) The synthetic resin emulsion containing modified polyvinyl alcohol containing silicon in the molecule as an emulsifier is obtained by emulsion polymerization of ethylenically unsaturated monomers in the presence of the modified polyvinyl alcohol, Claim 1
Coating agent for porous inorganic materials as described in Section 0 (8) The synthetic resin emulsion containing modified polyvinyl alcohol containing silicon in the molecule as an emulsifier is obtained by post-emulsifying the synthetic resin in the presence of the modified polyvinyl alcohol. A coating agent for porous inorganic materials according to claim 1. (phrase) A patent claim in which modified polyvinyl alcohol containing silicon in the molecule is a modified polyvinyl alcohol obtained by saponifying a vinyl ester, an ethylenically unsaturated monomer containing silicon in the molecule, and a zero copolymer. Coating agent for porous inorganic materials according to item 1. (5) The ethylenically unsaturated monomer is one or two selected from the group consisting of vinyl acetate, ethylene, and (meth)acrylic acid ester. Claim 2 which is the above mixed proboscis
Coating agent for porous inorganic materials described in Section 0