JPH08879B2 - Water resistant composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a water resistant composition comprising a specific modified polyvinyl alcohol.

B. Conventional Technology Conventionally, polyvinyl alcohol (hereinafter, polyvinyl alcohol may be abbreviated as PVA) has been widely used as various binders, adhesives, or surface-treating glues. It is known to have excellent performance while allowing the following. However, since PVA is water-soluble, it has a drawback that it is poor in water resistance, particularly when it is dried at a low temperature, and various methods have been studied to improve this drawback.

For example, a method of cross-linking PVA with glyoxal, glutaraldehyde, dialdehyde starch or the like, or a method of cross-linking with alkali metal tetraborate or the like is known. However, in order to make PVA sufficiently water resistant by the former method, it is necessary to perform heat treatment at a high temperature of 100 ° C or higher, especially at 120 ° C or higher for a long time. It is also known to use strongly acidic conditions, but there is a problem that the viscosity stability of the PVA aqueous solution is poor and gelation occurs during use. In addition, the latter method has the drawback that the water resistance obtained is insufficient and the viscosity stability of the PVA aqueous solution is poor.

Further, as a method for making a dialysis membrane in a laboratory, a chitosan compound and PVA obtained by dissolving chitosan having a high degree of polymerization in an acetic acid acid aqueous solution, or a dilute combination of the chitosan compound, PVA and glutaraldehyde is used. After forming a film from the solution, it is immersed in a strong alkaline aqueous solution to convert the ammonium notation in the chitosan-based compound that has been ammoniumated by acetic acid to amino notation to make the chitosan-based compound itself insoluble in water and PVA. There is also proposed a method of obtaining a film insoluble in cold water by highly saponifying ss. However, the conventionally used chitosan-based compound has a molecular weight of several hundred thousand [the viscosity of a 1% aqueous solution measured by a Brutsk field viscometer (hereinafter abbreviated as B-type viscometer) at 20 ° C. is 500 centipoise (hereinafter centipoise (abbreviated as cp) equivalent to or more than)] has a drawback that when used in combination with an aqueous solution of PVA, the viscosity becomes extremely high, it cannot be handled unless it is a dilute solution, and it becomes water-insoluble unless treated with an alkali. However, there is a problem that it cannot be used for industrial purposes.

C. Problems to be Solved by the Invention An object of the present invention is to provide a specific modified PVA which is extremely excellent in water resistance not only to cold water but also to hot water even when dried or heat-treated at a relatively low temperature. To provide a composition.

D. Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, saponified a modified polyvinyl ester having an alkoxysilane group on the side chain to obtain a saponification degree of 70 mol. % Or more of modified polyvinyl alcohol (A), 1% by weight aqueous solution
Chitosan compound (B) having a viscosity of 70 centipoise or less at 20 ° C and a content of amino groups (including those in which amino groups are converted into ammonium groups by an acid) per glucose unit of 40 mol% or more and one molecule A polyhydric aldehyde containing two or more aldehyde groups or a mixed aqueous solution of a water-soluble metal salt (C), and a weight mixing ratio [(A) / (B)] of the (A) component and the (B) component. Is 99/1 ~
10/90, weight blending ratio of component (C) {[(A) +
The present invention has been completed by finding a water resistant composition having (B)] / (C)} of 100/1 to 100/20.

The modified PVA (A) used in the present invention is obtained by saponifying a modified polyvinyl ester having an alkoxysilane group in its side chain. The modified PVA of the present invention is particularly preferably one in which the alkoxysilane group of the side chain of the modified polyvinyl ester as the raw material is hydrolyzed during the saponification reaction to be converted into a silanol group or a salt thereof.

Examples of the method for producing the modified PVA include a method of saponifying a modified polyvinyl ester having a side chain having an alkoxysilane group, which is a copolymer of a vinyl ester and an olefinic unsaturated monomer containing an alkoxysilane group.

The olefinic unsaturated monomer containing an alkoxysilane group used in the above-mentioned production method is at least 1
There is no particular limitation as long as it has one alkoxysilane group, and specific examples thereof include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris- (β-methoxyethoxy) silane, and allyltrimethoxysilane. , Vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, vinylisobutyldimethoxysilane, vinyltriisopropoxysilane,
Vinyltributoxysilane, vinyltrihexyloxysilane, vinylmethoxydihexyloxysilane, vinyldimethoxyoctyloxysilane, vinylmethoxydioctyloxysilane, vinyltrioctyloxysilane, vinylmethoxydilauryloxysilane, vinyldimethoxylauryloxysilane, Vinylmethoxydioleyloxysilane, vinyldimethoxyoleyloxysilane, 3- (meth) acrylamido-propyltrimethoxysilane, 3
-(Meth) acrylamide-propyltriethoxysilane, 3- (meth) acrylamide-propyltri (β-
Methoxyethoxy) silane, 2- (meth) acrylamido-2-methylpropyltrimethoxysilane, 2- (meth) acrylamido-2-methylethyltrimethoxysilane, N- (2- (meth) acrylamido-ethyl)-
Aminopropyltrimethoxysilane, 2- (meth) acrylamide-ethyltrimethoxysilane, 1- (meth)
Acrylamide-methyltrimethoxysilane, 3- (meth) acrylamide-propylmethyldimethoxysilane, 3- (meth) acrylamide-propyldimethylmethoxysilane, 3- (N-methyl- (meth) acrylamide) -propyltrimethoxysilane, etc. Can be mentioned.

When the modified polyvinyl ester is produced by the above method, a small amount of other unsaturated monomer may be copolymerized in addition to the vinyl ester and the alkoxysilane group-containing olefinic unsaturated monomer during the polymerization. . Such unsaturated monomers include styrene, alkyl vinyl ether, vinyl versatate, (meth) acrylamide, ethylene, propylene, α-hexene, olefins such as α-octenoic acid, (meth) acrylic acid, crotonic acid, (anhydrous ) Unsaturated acids such as maleic acid, fumaric acid and itaconic acid, and their alkyl esters, alkali salts, 2-
Acrylamide-2-methylpropanesulfonic acid and other sulfonic acid-containing monomers and their alkali salts, trimethyl-
2- (1- (meth) acrylamide-1,1-dimethylethyl) ammonium chloride, trimethyl-3- (1-
(Meth) acrylamidopropyl) ammonium chloride, 1-vinyl-2-methylimidazole and its 1
To cationic monomers such as quaternary compounds.

The content of the alkoxysilane group in the modified polyvinyl ester used in the present invention, the saponification degree of the modified PVA, and the polymerization degree of the modified PVA are not particularly limited. The content of the alkoxysilane group in the modified polyvinyl ester is effective even in a relatively small amount, and the content of the monomer unit containing the alkoxysilane group is usually 0.01 to 10 mol%, preferably 0.1 to 5 mol. It is selected from the range of%. The saponification degree of the modified PVA is 70 mol% or more. The degree of polymerization of the modified PVA is usually selected from the range of 10 to 3000.

Examples of the chitosan compound (B) used in the present invention include those containing 40 mol or more of amino groups per glucose unit, or those in which some or all of these amino groups are converted to ammonium groups by an acid. used. As the degree of polymerization of the chitosan compound, the viscosity of a 1% by weight aqueous solution at 20 ° C. (hereinafter, the aqueous solution viscosity of the chitosan compound means the viscosity measured by a B-type viscometer in an aqueous solution or an acidic hydroxide solution). ) Is 70 cp or less, and a low degree of polymerization that is subjected to a special depolymerization treatment is necessary, 1 to 30 cp is more preferable, and 1 to 10 cp is particularly preferable.

The above-mentioned chitosan compound used in the present invention is, for example, chitin as a raw material, which is then deacetylated into chitosan by a usual method of alkali treatment in a heterogeneous system to give chitosan, and further alkali treatment or acid treatment or peroxide. Depolymerization to a high degree by treatment, or deacetylation and depolymerization by homogeneous treatment in a solvent of chitin by alkali treatment,
In some cases, it can be produced by further performing an acid treatment or a peroxide treatment. Of the above-mentioned chitosan compounds, when the amino group is not converted to an ammonium salt, it is generally insoluble in water, so it dissolves in water in the presence of an acid to the extent that some or all of these amino groups become ammonium salts. However, when the amino group is converted into an ammonium salt or when the amino group content is 40 to 60% produced by the above-mentioned homogeneous system,
It can be dissolved in water as it is. The acid used for the above-mentioned dissolution is not particularly limited, but usually acetic acid, formic acid,
Citric acid, fumaric acid, maleic acid, sulfamic acid, hydrochloric acid, phosphoric acid, sulfuric acid and the like are used.

Specific examples of the polyvalent aldehyde (C) containing two or more aldehyde groups in one molecule used in the present invention include polyvalent aldehydes such as glyoxal, glutaraldehyde, and dialdehyde starch. Among the above-mentioned aldehyde compounds, glyoxal is preferably used from the viewpoint of ease of use of the obtained composition (odorless, viscosity stability, etc.) and water resistance effect.

As the water-soluble metal salt (C) used in the present invention,
Examples thereof include chlorides or sulfates such as aluminum, iron, copper, zinc, tin, titanium, nickel, Agnesium, vanadium, chromium and zircon. Among the above-mentioned metal salts, aluminum chloride, aluminum sulfate, potassium salt,
Ammonium alum and the like are preferably used from the viewpoint of water resistance.

In the water resistant composition of the present invention, the weight ratio of the modified PVA (A) and the chitosan compound (B) is [(A) /
(B)] is 99/1 to 10/90, preferably 95/5 to 50/5
It is 0, more preferably 90/10 to 60/40. Further, the polymerization compounding ratio {[(A) + (B)] / (C)} of the polyvalent aldehyde or the water-soluble metal salt (C) is 100/1 to 100/20. If (A) / (B) exceeds 99/1, there is no water resistance effect, and if it is less than 10/90, the strength of the obtained coating film decreases.

Further, when {[(A) + (B)] / (C)} exceeds 100/1, the water resistance effect is low, and when it is less than 100/20, the viscosity stability of the water resistant composition of the present invention is stable. The sex becomes worse.

The water resistant composition of the present invention comprises the modified PVA (A) as described above,
A chitosan compound (B) having a viscosity of 70 cp or less and a polyvalent aldehyde or a water-soluble metal salt (C) of a 1 wt% aqueous solution are essential components, and water is used as a solvent. Various alcohol ketones, dimethylformamide, dimethylsulfoxide and the like can be used in combination with water as the solvent of the present invention. Furthermore, various defoaming agents, various dispersants, nonionic or anionic surfactants,
Additives such as silane coupling agents or pH adjusters; cellulose derivatives such as carboxymethyl cellulose, hydroxyethyl cellulose, poly (meth) acrylic acid, polyhydroxy (meth) acrylate or its copolymers, (meth) acryl such as polyacrylamide -Based polymers, water-soluble resins such as polyvinylpyrrolidone or copolymers thereof; acrylic polymers and copolymers, ethylene-vinyl acetate copolymers, vinyl ester-based polymers and copolymers, styrene-butadiene copolymers, etc. The aqueous dispersion of can be added as appropriate.

The water-resistant composition of the present invention makes use of film-forming property, film strength or water resistance, and is an adhesive for inorganic substances or organic substances,
It is effectively used as a vehicle for paints, a treatment agent for inorganic materials or organic materials (surface coating agents, etc.), and also for applications where water-soluble resins have been conventionally used such as films and sheets. In particular, the modified PV in the water resistant composition of the present invention
Since A has a high reactivity with an inorganic substance and a high water resistance, the water resistant composition of the present invention is preferably used as an adhesive, a binder or a treating agent for a material containing an inorganic pigment and the like.

E. Action and effect of the invention The reason why the water-resistant composition of the present invention is excellent in film-forming property, film strength, and water resistance is not fully understood, but in the water-resistant composition of the present invention. Modified PV used
The vinyl ester unit or vinyl alcohol unit in A exerts film-forming properties, and the modified PVA has extremely high compatibility with chitosan compounds, especially low-viscosity chitosan compounds, and is compatible at the molecular level. However, when dried to form a film, it is presumed that high film strength and water resistance are exhibited because crosslinking between the two is easily caused by the polyvalent aldehyde or the water-soluble metal salt.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In the examples, "%" and "parts" are based on weight unless otherwise specified.

Example 1 A saponification degree of a vinyl acetate unit obtained by saponifying a copolymer of vinyl trimethoxysilane and vinyl acetate (vinyl trimethoxysilane unit content: 0.3 mol%) of 98.5 mol%, a polymerization degree of 1300 A modified PVA of 10% of this modified PVA
To 100 parts of an aqueous solution, 1.5 parts of a chitosan compound having an amino group content of 100 mol% per glucose unit converted to an ammonium salt with acetic acid having a viscosity of 5 cp at 20 ° C. of a 1% aqueous solution was added and dissolved to give 40% An aqueous solution of the water resistant composition was prepared by adding 1 part of glyoxal. ((A) /
(B) = 87/13, [(A) + (B)] / (C) = 100/3.
Five). This solution was cast and dried at 50 ° C. to prepare a sheet. The obtained sheet-like material was insoluble in hot water (40 ° C) and hot water (95 ° C), and maintained a tight film state.

Examples 2 to 6 The procedure of Example 1 was repeated, except that the weight ratio of the modified PVA used in Example 1 to the chitosan compound was changed as shown in Table 1. The results are shown together in Table 1.

Comparative Example 1 The procedure of Example 1 was repeated except that the chitosan compound used in Example 1 was not used. First result together
Shown in the table.

Comparative Example 2 The procedure of Example 1 was repeated, except that glyoxal was not used. The results are shown together in Table 1.

Comparative Example 3 PVA having a polymerization degree of 1750 and a saponification degree of 98.5 mol% (Kuraray Poval PVA-117) was used, and the same procedure as in Example 1 was performed except that no chitosan compound was used. The results are shown together in Table 1.

Comparative Example 4 The procedure of Example 1 was repeated except that the modified PVA used in Example 1 was replaced with the PVA-117 used in Comparative Example 3 and no glyoxal was used. The results are shown together in Table 1.

Comparative Examples 5 to 6 Comparative Example 5 was carried out in the same manner as in Example 1 except that the weight ratio (A) / (B) of the modified PVA and the chitosan compound used in Example 1 was changed as shown in Table 1. First result together
Shown in the table.

Comparative Example 7 Instead of the modified PVA and chitosan compound used in Example 1, PVA-117 used in Comparative Example 3 and a 1% aqueous solution at 20 ° C.
The same procedure as in Example 1 was carried out except that a chitosan compound having a viscosity of 700 cp was used. In this case, the solution had a very high viscosity and a gel form. The results are shown together in Table 1.

As shown in Table 1, it can be seen that the water resistant composition of the present invention has remarkably excellent water resistance even when dried at a relatively low temperature of 50 ° C.

Example 7 Saponification degree of vinyl acetate unit of 88 mol obtained by saponifying a copolymer of 3-methacrylamido-propyltriethoxysilane and vinyl acetate (content of methacrylamide silane unit: 0.5 mol%). %, Modified PVA with a degree of polymerization of 500
Chitosan 30 with 70 parts and a 1% aqueous solution with a viscosity of 25 cp at 20 ° C and an amino group content of 99 mol% per glucose unit
A part was dissolved in an aqueous solution to which an appropriate amount of citric acid was added to prepare a 10% aqueous solution. The pH of this solution was 4.7. To this solution, add a 10% aqueous solution of aluminum sulfate [(A) +
(B)] / (C) was added to 100/5 to prepare an aqueous solution of the water resistant composition of the present invention. Cast this aqueous solution
A sheet was obtained by drying at 50 ° C. This sheet is 40
It was insoluble in warm water at ℃ and maintained a tight film.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kouji Takano, 1621 Sakata, Kurashiki, Okayama Prefecture, Kuraray Co., Ltd. (72) Inventor, Junnosuke Yamauchi, 1621 Sasakazu, Kurashiki, Okayama, (72) Inventor, Kuraray Co., Ltd. Takuji Okaya 1621 Sakata, Kurashiki City, Okayama Prefecture Kuraray Co., Ltd. (56) References JP-A-61-211357 (JP, A)

Claims (1)

[Claims] 1. A modified polyvinyl alcohol (A) having a saponification degree of 70 mol% or more obtained by saponifying a modified polyvinyl ester having an alkoxysilane group in its side chain, and a viscosity of an aqueous 1% by weight solution at 20 ° C. of 70 centipoise or less, and Chitosan compound (B) having a content of amino groups (including those in which an amino group is converted to an ammonium group by an acid) per glucose unit of 40 mol% or more and 2 in one molecule
It is composed of a mixed aqueous solution of a polyhydric aldehyde containing one or more aldehyde groups or a water-soluble metal salt (C), and the weight mixing ratio [(A) / (B)] of the (A) component and the (B) component is 99.
From 1 to 10/90, the blending ratio by weight of the component (C) {[(A) +
(B)] / (C)} is 100/1 to 100/20.