JPS5869764A - Admixing agent for cement - 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 cement admixture, and more specifically, a modified polyvinyl alcohol having a cationic group in the molecule.
A quick review of cement admixtures.

Traditionally, polymer emulsion. Latex or polyvinyl alcohol (hereinafter referred to as polyvinyl alcohol)
It is abbreviated as VA. ) Methods of improving the mechanical properties of cement by mixing water-soluble polymers such as methylcellulose into cement are widely used. Among these methods, polymer emulsions or latexes are aqueous liquids and are complicated to handle.

Moreover, the abrasion resistance is not sufficiently improved, and although % and PVA % menal cellulose can be handled in powder form, the effect is small.

The purpose of the present invention is to solve these drawbacks, and by mixing modified PVA containing a cationic group in one molecule with cement (mortar or concrete), mechanical properties such as bending, compression, and abrasion resistance can be improved. The present inventors have discovered that they can provide a seven-mention composition that not only has excellent mechanical strength, but also has dramatically improved adhesion to adherends, and also has excellent water resistance, weather resistance, alkali resistance, etc.

That is, one aspect of the present invention is a cement admixture made of modified PVA containing a cationic group in its molecule.

The present invention will be explained in more detail below. The cationic groups contained in the modified PVA used in the present invention are primary amines,
Secondary aban, tertiary amine, quaternary ammonium salt, pyridine, pyridinium, imidazole, imidazolinium,
It refers to chemical structural units such as sulfonium and phosphonium that dissociate in aqueous solution and become positively charged. Conventionally reported methods for producing cation-modified PVA include a method in which vinyl pyridine and vinyl acetate are copolymerized and then saponified;
A method in which vinyl phthalimide or N-vinylsuccinimide and vinyl acetate are copolymerized and then silicified, and the imide group is further decomposed with an alkali or hydrazine. A method in which PVA is converted into aminoacetal or aminobenzacetal under an acid catalyst. PVA with alkoxydimethylamine, glycidyltrimethylammonium hydrochloride or 3
- Method of reacting chloro-2-hydroxypropyltrimethylammonium dioate, PVA with acrylic 7)
A method is known in which a diamino group is introduced by Hofmann decomposition after adding a micole with '.

Cation-modified PVA synthesized by these methods can also be used in the cement admixture of the present invention, but the above-mentioned method for producing cation-modified PVA requires various difficult problems in the cationization process itself to be implemented industrially. be.

On the other hand, the following general formulas (1), (II), (II
Modified PVA containing the copolymerized units shown in I) or (IV) not only exhibits cationic activity, but also has a stable and easy industrial method for introducing cationic groups and obtaining a desired degree of saponification. Possible OR5 and R6 are hydrogen atoms or alkyl groups (which may contain substituents), X is an anion, and A is a group that connects the nitrogen atom in B and the nitrogen atom of the amide group, respectively. ) (Here, R7, ♂, ♂ mean a hydrogen atom, a lower alkyl group or a phenyl group, R10 means an alkyl group (which may contain a substituent), and X means an anion.) ♂, ♂ are 9 represents a hydrogen atom, 9 represents an alkyl group (which may contain a substituent), X represents an anion, and %D represents an aliphatic group connecting the nitrogen atom in B and the oxygen atom of the ether group. ) The production of modified PVA containing copolymerized units represented by the above general formulas (1) to (IV) is carried out using vinyl esters, especially vinyl acetate, and the following formulas (a) to (d) Co-N-A-B "NO♂" CH2=CH CH2-CH-0-D-B (d)
(Here, R1-R3, R7-R10, X-1A%B,
The meaning of D is the same as above. ) in the presence of a radical polymerization initiator, and then an alkali or acid catalyst is applied to the alcohol solution of the copolymer to form the vinyl ester in the copolymer. It is effectively and easily produced by partially or highly saponifying the unit to form a vinyl alcohol unit depending on the purpose. In the monomer represented by the general formula (a), R1 and R2 are hydrogen atoms or Although it is a lower alkyl group,
Generally, a hydrogen atom or a methyl group is preferable, and a hydrogen atom is more preferable since the polymerization rate in the copolymerization reaction with vinyl acetate is high. R3 also represents hydrogen, ♂ represents a hydrogen atom or an alkyl group which may contain a substituent, and X- represents an anion. ♂, R5, and ♂ are all preferably methyl groups for normal purposes, but for special purposes, lower alkyl groups such as ethyl groups and propyl groups, or methylol groups for the purpose of imparting reactivity, or increasing the density of cationic groups. An alkyl group containing a substituent such as an azenoalkyl group is also used for the purpose of X is a halogen atom such as chlorine, oxaline, iodine, or CM! 10808 or CIIaCgH4SOs are preferred, but chlorine atoms are particularly preferred from the economic, safety, and physical properties of modified PVA. When B is in the form of a quaternary ammonium salt, the effects of the present invention can be exhibited even with primary to tertiary amines, which are preferable for ease of handling in the production of modified PVA. The group that connects the nitrogen atom in the amino group B and the mass atom of the amide group can be any group that contains a stable bond, but usually a linear or branched aliphatic group is used. Among the monomers represented by the above general formula (a) that can be used, the following are specific examples of monomers in the form of tertiary amines.

N-(2-dimethylaminoethyl)acrylamide, N
-(2-dimethylaminoether)methacrylamide, N
-(3-dimethylaminepropyl)acrylamide, N
-(3-diethylaminopropyl)acrylamide, N
-(3-diethylaminopropyl)methacrylamide,
N-(3-diethylaminepropyl)methacrylamide, N-(1,1-dimethyl-3-dimethylaminopropyl)acrylamide, N-(l,1-dimethyl-3-diethylaminopropyl)methacrylamide, N-(1 ，
1-diethyl-3-dimethylaminobutyl)acrylamide, N-(1-methyl-1,3-diphenyl-3-1
diethylaminopropyl) methacrylamide, N-(3
-dimethylaminoethyl)acrylamide, N-(3-
methylethylaminopropyl) methacrylamide, N-
Methyl-N-(3-dimethylaminopropyl)acrylabad, N-(2,2-dimethyl-3-dimethylaminopropyl)acrylamide, N-(2,2-dimethyl-
3-dimethylaminopropyl) methacrylamide s N
-(2,2-dimethyl-3-dimethylaminopropyl)
Crotonic acid amide, N-(3,3-dimethyl-4-dimethylaminobutyl)acrylamide, N-(3,3-dimethyl-4-dimethylaminobutyl)methacrylamide, N-(3,3-dimethyl-4- dimethylaminobutyl) crotonic acid amide.

Among the monomers represented by the above general formula (a), those in the form of quaternary ammonium can be easily obtained by quaternizing the above-mentioned tertiary amine deafening monomer with the following known quaternizing agent. can be obtained. dialkyl sulfate, e.g. dimethyl sulfate,
Diethyl sulfate, dipropyl sulfate, Cl-04-esters of alkyl or arylsulfonic acids, 91. methyl-, ethyl-, propyl- or butyl esters such as methanesulfonic acid, hensensulfonic acid or toluenesulfonic acid, henzyl% N, [benzyl chloride or benzyl bromide] alkyl,
Examples include methyl chloride, methyl bromide, methyl iodide, ethyl chloride, ethyl bromide, or ethyl iodide.

The following four types of monomers among the above-mentioned examples of the monomers represented by the general formula (A) are N-(1,1-dumenal-3-dimethylaminoglovir)acrylamide CHa trimethyl- (3-acrylamido-3,3-dimethylpropyl)ammonium chloride? H8 CH2=CH-C0N)(-C-CH2CHzN (C
f(a)sαruH3 N-(3-diethylaminoprobyl) methacrylamide? H3 GHz-C-CONHCH2CHzCH2N(CHa)
2-trimethyl-(3-methacrylamido-propyl)ammonium chloride? H3- 0M2-C-CONHcH2eHtCHxN (CHs
) and α are excellent in producing the modified PVA of the present invention from the viewpoints of polymerization rate, stability of the amide group, and economy during monomer production.

In addition, examples of the monomer shown in (b) above include 1
-vinylimidazole, 1-vinyl-2-methylimidazole, 1-vinyl-2-ethylimidazole, 1-vinyl-2-phenylimitasol, 1-vinyl-2,4
, 5-trimethylimidazole and the like. Further, the monomer represented by the above general formula () and ) can be easily obtained by quaternizing the monomer represented by the above general formula (b) with the above-mentioned quaternizing agent.

Examples of the monomer represented by the above general formula (2) include dimethylaminoethyl vinyl ether, dimethylaminopropyl vinyl ether, and a quaternized chain thereof such as vinyloxyethylamine.

Furthermore, modified PVA in which the cationic group is a copolymerized unit represented by the following general formula (V) or (Vl) is also effective for the present invention.

11 +CH2-C-) (y) R12R13 R" (Here, R11, R12, R13 are hydrogen atoms or lower alkyl groups, R14 is an alkyl group, and X- is an anion.) Although it was more difficult than expected to incorporate vinylamine copolymerized units into the molecule, and no effective method was known yet, the present inventors discovered that vinyl esters, especially vinyl acetate and N-
Vinylacetamide, N-vinyl-N-methylacetand or N-vinyl-N-methylformamide, or methyl-N-vinylcarbamate, ethyl-N-
vinylcarba/-), t@rt-f-N-vinylcarbamate, methyl-N-impropenylcarbamate, ethyl-N-4-impropenylcarbamate), ta
By copolymerizing an unsaturated carbamate compound such as rt-methyl-N-isopropenyl carbamate in the presence of a radical polymerization initiator, and then hydrolyzing the copolymer, N-vinylalkylamide can be obtained. It has been shown that the amide group in the unit or the carbamate group in the carbamate group-containing monomer unit can be hydrolyzed to form a vinylamine unit, and thus modified PVA containing any amount of vinylamine units can be produced. We have also found that

The amount of cationic groups in the cationic group-modified PVA used as the cement admixture of the present invention, the saponification degree or the modified PV
The degree of polymerization of A is appropriately selected depending on the purpose and is not particularly limited, but for many purposes, the degree of polymerization of the cationic group is 0.01 to 0.01.
10 mol, particularly preferably 0.1 to 3 mol, degree of saponification 50 to 100 mol, particularly preferably 68 to 100
Mol%, degree of polymerization is 100 to 4000, particularly preferably 5
Selected from the range of 00 to 2500.

In the present invention, the amount of modified PVA added is preferably from 0.01 to 30% by weight, particularly from 0.05 to 10% by weight, based on the amount of 70% by weight. If the amount is as small as 0.01% by weight, it is virtually the same as not adding it, and no effect can be seen;
This is because the fluidity of cement tends to deteriorate in children over 100%, and there is no need to add such a large amount. As for the addition method, it is convenient to use a fine powder of cationic group-modified PVA from the viewpoint of workability, but a method of adding an aqueous solution can also be used.

Although the modified PVA of the present invention exhibits high effectiveness even when used alone, other admixtures such as polymeric emulsion/or latex, PVA.

It is also possible to use modified PVA or cellulose derivatives in combination, and good results can be obtained depending on the purpose.

Hereinafter, the present invention will be explained with reference to examples.
C means parts by weight or weight % unless otherwise specified.

Example 1 and Comparative Example 1.2 A copolymer of trimethyl-(3-acrylamido-3,3-dimethylpropyl)ammonium chloride and vinyl acetate was saponified to form trimethyl-(3-acrylamido-3,3-dimethylpropyl) as a cation group.
A cationic group-modified PvA containing 2 mol of -acrylamide-3,3-dimethylpropyl)ammonium chloride units and a saponification degree of vinyl acetate units of 92 mol-1 and a polymerization degree of 1800 was obtained. 0.5 parts of fine powder is added to 100 parts of Portland cement and 300 parts of Toyoura standard sand, and the mortar has a 70-value of 1.
Add 65 parts of water and knead to make it 70, JIS-R5
The strength was measured after molding according to ``Physical Test Methods for 201R Cement'' under standard conditions (20''CA65%RH) for 4 weeks.In addition, the mortar after mixing with Ml was molded in accordance with the 20-minute theory on a mortar board ( A cement-sand ratio of 1:2 was cured for 4 weeks. A slate board was immediately attached to a 40x40IIJ) to a thickness of 3u. After 4 weeks of standard conditions, a curing gun and measuring jig were attached. The adhesive strength was determined in g1 using an autobluff at a tensile speed of 1 m/min.The I$IIJ determination results are shown in Table 1. The results of the definition performed in the same manner as in Example 1 are also shown in Table 1. In the composition of the present invention (implementation fill) using cationic group-modified PVA, compared to each comparative example,
Table 1 Examples 2 to 10 Instead of the cationic group-modified PVA1C of Example 1, a copolymer of vinyl acetate and various comonomers was obtained by saponifying it.

Except for using the cationic group-modified Pv membrane shown in Table 2,
Physical properties of the cement mortar composition were measured in the same manner as in IA Example 1. The results are shown in Table 3. Mortar containing cationic group-modified PVA has extremely excellent strength and adhesive strength.

Table 2 below (Note 1) A methanol solution of a copolymer of t@rt-butyl-N-vinylcarnocoumate and vinyl acetate was acid saponified using sulfuric acid as a catalyst to decompose the carno(mate group and produce vinylamine units). Obtained PVA containing 90 (Note 2)
A copolymer of N-vinylacetamide and vinyl acetate was saponified using an alkali catalyst, and an aqueous solution of the saponified product was treated with caustic soda at 100°C to decompose the amide group and contain vinylamine units to obtain 9-PVA. Ta.

No. 3#I

Claims (1)

[Scope of Claims] 1) A cement admixture comprising modified polyvinyl alcohol containing a cationic group in the molecule. 2) The admixture for cement according to claim 1, wherein the modified polyvinyl alcohol containing a cationic group in the molecule is a modified polyvinyl alcohol containing a copolymerized unit represented by the following general formula (1). ♂ Table 3 R4, Hll, and R6 each represent a hydrogen atom or an alkyl group (which may contain a substituent), X represents an anion, and A represents a group that connects the nitrogen atom in B with the nitrogen atom of the amide group. . 3) The admixture for cement according to claim 1, wherein the modified polyvinyl alcohol containing a cationic group in the molecule is a modified polyvinyl alcohol containing a copolymerized unit represented by the following general formula (1) or (II). . (-CH2-CH-)- (Here, R', R', and ♂ are hydrogen atoms, lower alkyl groups, or phenyl groups, R10 is an alkyl group (which may contain a substituent), and X is an anion. 4) The blend for cement according to claim 1, wherein the modified polyvinyl alcohol containing a cationic group in the molecule is a modified polyvinyl alcohol containing a copolymerized unit represented by the following general formula (W). agent. R5 and R6 are hydrogen atoms or alkyl groups (substituents t-t
%X is an anion, D is a nitrogen atom in B and i
! ll each means an aliphatic group connecting elementary atoms. ) 5) The blend for cement according to claim 1, wherein the modified polyvinyl alcohol containing a cationic group in the molecule is a modified polyvinyl alcohol containing a copolymerized unit represented by the following general formula (V) or (Vl). agent. 11 "R14R" (where R", R", ♂ are hydrogen atoms or lower alkyl groups, R14 is an alkyl group (which may contain substituents)
, X each represent an anion. )