JPS59187697A - Filler fixing agent for paper - 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 filler fixing agent for paper, and more specifically to a filler fixing agent for paper that has a high filler retention performance and is made of modified polyvinyl alcohol having a silyl group in the molecule (hereinafter, modified polyvinyl alcohol is abbreviated as PVA). 9 Regarding filler fixing agents Fillers such as aluminum hydroxide, clay, talc, kaolin, calcium carbonate, and titanium oxide have traditionally been used in paper manufacturing for the purpose of improving various properties of paper such as improving paper opacity. ing. Since these fillers generally have poor fixation to cellulose fibers, water-soluble polymeric substances such as polyacrylamide and polyethyleneimine, inorganic salts such as sulfuric acid clay, and polyaluminum chloride have traditionally been used as filler flocculants. . However, in recent years, there has been a trend to replace cellulose fibrous materials with cheaper fillers due to a worldwide shortage of high-quality raw wood for valves, resource conservation issues, and lower manufacturing costs. There is currently a need for good filler fixing agents.

In view of the above-mentioned current situation, the present inventors conducted intensive research on filler fixing agents that can produce paper with a very high filler content.
When VA is used as a filler adhesion agent, the filler retention is significantly higher and it is possible to produce papers with high filler content while maintaining most of the paper's stiffness, wet strength, tensile strength and other physical properties. They discovered this and completed the present invention.

The present invention will be explained in more detail below.

Modified P containing a silyl group in the molecule used in the present invention
VA may be of any type as long as it contains silicon in the molecule, but the silyl group contained in the molecule may be an acyloxyl group, or a reactive substituent such as a silanol group which is a hydrolyzate thereof, or a salt thereof. Those having the following are particularly preferably used.

Methods for producing such modified PVA include: (1) introducing a silyl group into PVA or modified polyvinyl acetate containing a carboxyl group or a hydroxyl group by post-modification using a silylating agent; (2) a method of introducing a silyl group into PVA or modified polyvinyl acetate containing a carboxyl group or a hydroxyl group by post-modification; Method of saponifying a copolymer with an unsaturated monomer ■ A method of saponifying a polyvinyl ester having a silyl group at the terminal obtained by polymerizing a vinyl ester in the presence of a mercaptan having a silyl group. .

In the method of post-modifying PVA or modified polyvinyl acetate using a silylating agent, for example, the silylating agent is added to an organic solvent that does not react with the silylating agent, such as benzene, toluene, xylene, hexane, heftane, ether, or acetone. Dissolve the powdered PVA or the above-mentioned modified polyvinyl acetate in the solution with stirring, and let it cool at room temperature to
The silylating agent and P at a temperature in the range of the boiling point of the silylating agent.
Silicon-containing modified PVA by reacting VA or the above-mentioned modified polyvinyl acetate, or by further saponifying vinyl acetate units with an alkali catalyst etc.
can be obtained. Examples of silylating agents used in post-modification include organohalogensilanes such as trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, vinyltrichlorosilane, diphenyldichlorosilane, and triethylfluorosilane, trimethylacetoxysilane, and dimethyldiacetoxysilane. organosilicon esters such as silane, trimethylmethoxysilane,
Examples include organoalkoxysilanes such as dimethyldimethoxysilane, orcassilanols such as trimethylsilanol and diethylsilanediol, aminoalkylsilanes such as N-aminoethylaminoprobyltrimethoxysilane, and organosilicon isocyanates such as trimethylsilicon isocyanate. The rate of introduction of the silylating agent, that is, the degree of modification, can be arbitrarily adjusted by adjusting the amount of the silylating agent used and the reaction time. The polymerization degree and saponification degree of the obtained silyl group-containing modified PVA are determined by the P used.
The degree of polymerization and saponification of VA or the degree of polymerization and saponification reaction of the above-mentioned modified polyvinyl acetate can be adjusted as desired.

In addition, in a method of saponifying a copolymer of a vinyl ester and an olefinically unsaturated monomer containing a silyl group, for example, the vinyl ester and the olefinically unsaturated monomer containing a silyl group are radical-initiated in alcohol. A silyl group-containing modified PVA can be obtained by copolymerizing the copolymer using a copolymer and then saponifying the copolymer by adding an alkali or acid catalyst to an alcohol solution of the copolymer. Vinyl esters used in the above method include vinyl acetate, vinyl propionate, vinyl formate, etc., but vinyl acetate is preferred from an economical standpoint. Examples of the silyl group-containing olefinically unsaturated monomer used in the above method include vinylsilanes represented by the following formula (I) and (meth)acrylamide-alkylsilanes represented by (IF).

m 0H3=CH-(OIli2)n Si (R2)
3-m (I) Ir n! m 11 [Here, n is 0 to 4. m is 0 to 2, W is an alkyl group having 1 to 5 carbon atoms (methyl, ethyl, etc.), W is 1 to 4 carbon atoms
0 alkoxyl group or acyloxyl group (here, the alkoxyl group or acyloxyl group may have an oxygen-containing substituent) t is a hydrogen atom or a methyl group,
W represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and V represents a fullylene group having 1 to 5 carbon atoms or a divalent organic residue in which chain carbon atoms are bonded to each other via oxygen or nitrogen. Note that when two R1's exist in the same monomer, W may be the same or different. Furthermore, when two or more π exist in the same monomer, t may be the same or different.

Specific examples of vinylsilanes represented by formula (I) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, vinyltriacetoxysilane, allyltrimethoxysilane, allyltriacetoxysilane, Hinylmethyldimethoxysilane, Hinyldimethylmethoxysilane, Hinylmethyldiethoxysilane, Vinyldimethylethoxysilane, Vinylmethyldiacetoxysilane, Vinyldimethylacetoxysilane, Vinylisobutyldimethoxysilane, Vinyltriisopropoxysilane, Vinyltributoxysilane , vinyltrihexyloxysilane, vinylmethoxydihexyloxysilane, vinyldimethoxyoctyloxysilane, vinylditoxyoctyloxysilane, vinyltrioctyloxysilane, vinylmethoxydioleyloxysilane, vinyldimethoxylauryloxysilane, vinylmethoxydio Examples include polyoxysilane, vinyldimethoxyoctyloxysilane, and polyethylene glycolized vinylsilane represented by the general formula % (where m is the same as above and X represents 1 to 20). Further, as a specific example of the (meth)acrylamide-alkylsilane represented by the formula (n), for example, 6
-(meth)acrylamide-propyltrimethoxysilane, 3-(meth)acrylamidopropyltriethoxysilane, 3-(meth)acrylamide-propyltri(β-methoxyethoxy)silane, 2-(meth)acrylamide-2 -Methylpropyltrimethoxysilane, 2
-(meth)acrylamido-2-methylethyltrimethoxysilane, N (2(meth)acrylamido-ethyl)-aminopropyltrimethoxysilane, 6-(meth)
Acrylamide-propyltriacetoxysilane, 2-
(meth)acrylamide-ethyltrimethoxysilane,
1-(meth)acrylamido-methyltrimethoxysilane, 6-(meth)acrylamido-propylmethyldimethoxysilane, 3-(meth)acrylamido-pyrudimethylmethoxysilane, 3-(N-methyl=(meth)
Acrylamide)-propyltrimethoxysilane, 6-
((meth)acrylamide-methoxy)-3-hydroxypropyltrimethoxysilane, 3-((meth)acrylamide-methoxy)-propyltrimethoxysilane, dimethyl-6-(meth)acrylamide-propyl-
5-(1-rimethoxysilyl)-propylammonium chloride, dimethyl-2-(meth)acrylamide-
Examples include 2-methylpropyl-3-(trimethoxysilyl)propylammonium chloride.

In addition, in producing the modified PVA used in the present invention, the above-mentioned 2.
Other unsaturated monomers copolymerizable with the monomers other than the components, such as styrene, alkyl vinyl ether, vinyl versatate, (meth)acrylamide, ethylene,
Olefins such as propylene, α-hexene, α-octene, unsaturated acids such as (meth)acrylic acid, crotonic acid, (anhydrous) maleic acid, fumaric acid, and itaconic acid, and their alkyl esters, alkali salts, and 2-acdylamides. -2
- Sulfonic acid-containing monowaxes such as methylpropanesulfonic acid and their alkali salts, tritrimethyl-3-(1-(meth)acrylamidopropyl)ammonium chloride,
It is also possible to have a cationic monomer such as 1-vinyl-2-methylimitazole and its quaternized product present in a small proportion.

In addition, in a method of saponifying a polyvinyl ester having a silyl group at the terminal obtained by polymerizing a vinyl ester in the presence of a mercaptan having a silyl group, for example, when vinyl ester is polymerized using a radical initiator, silyl A mercaptan having a silyl group is added to the polymerization system all at once, in parts, or continuously, so that the mercaptan having a silyl group is present in the polymerization system, and by chain transfer to the mercaptan, a polyvinyl ester having a silyl group at the end is mainly formed. Thereafter, a modified PVA having a silyl group can be obtained by saponifying the polyvinyl ester by adding an alkaline or acidic catalyst to the alcohol solution of the polyvinyl ester.

As the mercaptan having a silyl group used in this method, 6-(trimethoxysilyl)-propylmercaptan, 3-()ethoxysilyl)-propylmercaptan, etc. can be used. In producing modified PVAfe by this method, it is also possible to include a small proportion of an unsaturated monomer copolymerizable with the vinyl ester used in method (2).

In the above-mentioned six production methods of modified PVA containing a silyl group in the molecule used in the present invention, bi-,
- A method for saponifying a copolymer of a polyester and an olefinically unsaturated monomer containing a silyl group, and a polyvinyl having a silyl group at the end obtained by polymerizing a vinyl ester in the presence of a mercaptan having a silyl group. A method of saponifying an ester is preferably used in terms of ease of industrial production and homogeneity of the resulting modified PVA.

Modified PV containing silyl group used in the present invention
The content of silyl groups in A, the degree of saponification, or the degree of polymerization are appropriately selected depending on the purpose and are not particularly limited. The effect of the silyl group is exhibited even at a relatively small content, and the monomer unit containing the silyl group is usually selected from the range of 0.01 to 10 mol%, preferably 0.1 to 2.5 mol%. The saponification degree is usually preferably in the range of 70 to 100 mol%. Further, the degree of polymerization is usually selected from the range of 10 to 6,000.

When dissolving the above-mentioned modified PVA used in the present invention in water, the modified ffA is usually dispersed in water. Depending on the case, an alkali such as sodium hydroxide is added, and a homogeneous aqueous solution is prepared by heating while stirring. Obtainable.

The fixing agent of the present invention is usually used as a water bath solution, and is added to an aqueous slurry containing a fibrous material mainly composed of cellulose fibers and a filler in a predetermined ratio. The amount of the fixing agent used in the present invention is 0.01 to 10% by weight, preferably 0.1 to 5% by weight based on the total dry weight of the cellulose fibrous material and filler. Further, conventionally known flocculants such as aluminum sulfate, aluminum chloride, aluminum hydroxide, sodium aluminate, polyethyleneimine, and cationic starch can also be used in combination. The filler to which the fixing agent of the present invention can be applied may be any filler that is normally used as a filler for paper manufacturing, such as clay, talc, kaolinite,
Examples include calcium carbonate, aluminum hydroxide, silicon oxide, calcium silicate, titanium oxide, or a mixture of two or more thereof. The particle size of the filler used is preferably 0.01 to 50 microns.

The cellulosic fibrous material to which the fixing agent of the present invention can be applied is mainly composed of cellulose fibers, and has a UP solubility of 50 to 600 in terms of Canadian standard water resistance (abbreviated as 0.8, F).
- is preferred, but in addition to the cellulose fibers, inorganic fibers such as glass fibers and rock wool fibers, organic synthetic fibers such as nylon, polyester, and polypropylene can also be used in combination.

In the present invention, there is no particular restriction on the blending ratio of the fibrous material mainly composed of cellulose fibers and the filler, but the weight ratio is usually 9.
5-5: 5-96 preferably 90-10: 10-9
It is selected from the range 0 and used.

According to the present invention, relatively expensive cellulose fibers can be replaced with inexpensive fillers, which is not only economically advantageous, but also has a high yield rate, so less filler flows into wastewater, which is an extremely significant advantage in terms of pollution prevention. is obtained.

Although the reason why the fixing agent of the present invention exhibits the above-mentioned remarkable effects is not fully elucidated, the modified PV having a silyl group in the molecule used in the present invention
Since the silyl group in A has high reactivity with inorganic substances and hydroxyl groups in cellulose, it is presumed that it aggregates the filler to some extent and reacts with cellulose fibers to exert the above-mentioned effect. The invention will be explained in more detail, but the invention is not limited thereto. In the examples, unless otherwise specified, "%" and "1 part" represent reference values.

Example 1 Vinyl) rimethoxysilane and acetic acid chloride,! : f) Modified PVA having a silyl group in the molecule by saponifying the copolymer and containing 1 mol% of silyl groups as vinyl silane units, a degree of saponification of vinyl acetate units of 99.5 mol%, and a degree of polymerization of 2000. I got it. This modified PVA is converted into modified PV
An aqueous solution of modified PVA was prepared by using water containing 2.5% sodium hydroxide based on A.

Next, 40 parts of wood pulp N-BKP (UP solution variation 0 S
, F, 430ml) and 60 parts of talc with a particle size of 0.1 to 10 microns (hereinafter microns will be abbreviated as μ) to prepare an aqueous slurry with a solid content concentration of 4%, and the above-mentioned denaturation slurry was prepared while stirring. A PVA water bath solution was gradually added to the solid content of the aqueous slurry to give a solid content of 1%, and the mixture was further stirred for 10 minutes. Using the aqueous slurry thus prepared, paper was made using a standard sheet machine in the same manner as a normal paper making method to give a paper weight of 130 yA, followed by dehydration and drying to obtain paper. The obtained paper was heated to 20℃
The sample was left for 48 hours in a constant temperature and humidity chamber at a constant temperature of 65%, and was used as a sample for measuring various physical properties. Table 1 shows the measurement results of various physical properties.

It can be seen from Example 1 that the fixing agent of the present invention has a high fixing rate and can yield paper with high strength.

Comparative Example 1 An anionic polyacrylamide polymer flocculant (molecular weight approximately 60
The same procedure as in Example 1 was carried out except that 0.5 parts of aluminum sulfate and 2 parts of aluminum sulfate were used. The results are shown in Table 1.

Examples 2 to 4 The same procedure as in Example 1 was carried out except that modified PVA as shown below was used instead of the modified PVA used in Example 1. The results are shown in Table 1.

Example 2: Contains 0.3 mol% of silyl groups obtained by saponifying a copolymer of vinyltriacetoxysilane and vinyl acetate as vinyl silane units, and the degree of saponification of vinyl acetate units is 99.0 mol%. Aqueous solution of modified PVA with a degree of polymerization of '2000.

Example 3 Contains 0.2 mol% of silyl groups obtained by saponifying a copolymer of dimethyl-2-acrylamido-2-methylpropyl-6-dorimethoxysilylbrobylammonium chloride and vinyl acetate as acrylamide units. , a water bath liquid of modified PVA with a degree of saponification of vinyl acetate units of 96 mol% and a degree of polymerization of 1750.

Example 4: Contains 2 mol% of silyl group units obtained by saponifying a modified polyvinyl acetate having a silyl group at the end obtained by polymerizing vinyl acetate in the presence of 6-trimethoxysilylpropylmerkabutane, 10% of modified PVA with vinyl acetate unit saponification degree of 99.0 mol% and polymerization degree of 50
Aqueous solution.

Table 1 1) Fixation rate; (ash content (%) in measurement sample / ash content (%) in raw material) Xi00 Example 5 Wood pulp N-BKP (UP solution degree 08.F, 43
0.4) 40 parts each of talc and clay with a particle size of 0.1 to 10μ to 20 parts, solid content concentration 4%
Example 1
The aqueous solution of modified PVA used in the above was gradually added so that the solid content was 6% based on the solid content of the aqueous slurry, and the mixture was further stirred for 10 minutes.

Example 1 Using the aqueous slurry prepared in this way
A sample paper was obtained in the same manner as above. Table 2 shows various physical property values measured in the same manner as in Example 1.

Comparative Example 2 Same as Example 5 except that 0.5 part of the anionic polyacrylamide polymer flocculant used in Comparative Example 1 and 2 parts of aluminum sulfate were used instead of the modified PVA aqueous solution used in Example 5. went. The results are also shown in Table 2.

Table 2 Patent applicant: RiRashi Co., Ltd. Agent: Patent Attorney Ken Honda

Claims (5)

[Claims] (1) A paper filler fixing agent made of modified polyvinyl alcohol having a silyl group in the molecule. (2) Claims characterized in that the modified polyvinyl alcohol having a silyl group in the molecule is a saponified product of a copolymer of a vinyl ester and an olefinically unsaturated monopolymers having a silyl group in the molecule. The filler fixing agent for paper according to item 1. (3) The filler fixing agent for paper according to claim 2, wherein the olefinically unsaturated monomer having a silyl group in the molecule is vinylalkoxysilane. (4) The filler fixing agent for paper according to claim 2, wherein the olefinically unsaturated monomer having a silyl group in the molecule is (meth)acrylamide-alkylalkoxysilane. (5) The scope of claims in which the modified polyvinyl alcohol having a silyl group in the molecule is a saponified product of a polyvinyl ester having a silyl group at the end obtained by pinning a vinyl ester in the presence of a mercaptan having a silyl group. The filler fixing agent for paper according to item 1.