JPS6221918B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a paper processing agent that prevents staining of dryer rolls and calender rolls due to adhesion of polyvinyl alcohol when polyvinyl alcohol is used for the purpose of paper processing. Improve paper size, paper surface strength,
In order to improve oil resistance, smoothness, etc., it is known to treat paper with an aqueous polyvinyl alcohol solution by means such as impregnation or coating. However, when the paper subjected to such treatment is dried by passing it between rolls in the next step, there is a problem that the dryer roll, canvas roll, and calender roll gradually become dirty, and the dirt gradually accumulates. Polyvinyl alcohol causes more staining than other paper treating agents. This dirt damages the surface properties of the paper and degrades the quality of the paper, so the roll surface must be cleaned from time to time. However, in high-speed machines, stopping the machine from time to time to clean the roll surface is so disadvantageous as to be fatal to productivity. Some things are beyond dispute. However, in order to deal with this problem, methods have been proposed in which additives such as polyhydric alcohol, paraffin emulsion, anionic surfactant, nonionic surfactant, urea, etc. are added to the polyvinyl alcohol aqueous solution, but the effect is Not necessarily enough. Moreover, these methods may, in some cases,
Disadvantages such as increasing the foaming properties of polyvinyl alcohol aqueous solutions, making polyvinyl alcohol coated paper repellent to water, making the paper more slippery, poor mechanical and chemical stability of the coating liquid, and decreasing printability. may be accompanied by However, the present inventors have conducted intensive research to solve the above-mentioned conventional problems, and as a result, when a polybasic acid partial ester salt is made to coexist in an aqueous solution containing polyvinyl alcohol as a main ingredient, it is difficult to treat the aqueous solution with a polybasic acid partial ester salt. Even if the paper is fed between the rolls,
The present invention was completed based on the discovery that stains do not occur on the roll surface for a long time, and that the inherent properties of polyvinyl alcohol paper processing agents, such as sizeability and printability, do not impair or, in fact, tend to be improved. I've reached it. As the polyvinyl alcohol in the present invention, polyvinyl alcohol with a degree of polymerization of 300 to 3000 is used, but depending on the purpose, polyvinyl alcohol with an extremely low degree of polymerization of about 50 to 300 can also be used. The degree of saponification of polyvinyl alcohol is approximately 40
A mol% to 100 mol% is used. Among these, an aqueous solution is not necessarily sufficient for those with a relatively low degree of saponification, but if used in combination with an organic solvent or an anionic surfactant, uniform dissolution is possible, so there is no particular problem in using them. The polyvinyl alcohol in the present invention also includes so-called modified polyvinyl alcohol. Examples of the modified polyvinyl alcohol include saponified copolymers of vinyl acetate and a comonomer copolymerizable with vinyl acetate. Comonomers include vinyl esters other than vinyl acetate (for example, vinyl propionate, vinyl stearate, vinyl benzoate, vinyl saturated branched fatty acids, etc.), unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, or alkyl esters thereof. , maleic acid, maleic anhydride, fumaric acid,
Unsaturated polyhydric carboxylic acids such as itaconic acid or their partial or complete esters, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, olefin sulfonic acids (e.g. ethylene sulfonic acid, allyl sulfonic acid, methalylsulfonic acid, etc.) Or the salt
Ethylene, propylene, butene, α-octene,
Examples include α-olefins such as α-dodecene and α-octadecene, and vinyl ether. The proportion of these comonomers in the copolymer is less than 30 mol %, preferably less than 20 mol %. Another group of modified polyvinyl alcohols are post-modified products of saponified homopolymers or copolymers of vinyl acetate as described above. Examples of post-modification include acetalization, urethanization, cyanoethylation, phosphoric acid esterification, sulfuric acid esterification, and sulfonic acid esterification. Next, a polybasic acid partial ester salt is a polybasic acid partial ester salt.
Some of the above carboxyl groups are esterified,
A compound that is partially in the form of a salt. As polybasic acids, unsaturated polycarboxylic acids such as maleic acid, fumaric acid, itaconic acid, glutaconic acid, methylmaleic acid, methylfumaric acid, and phthalic acid, and saturated polycarboxylic acids such as glutaric acid and succinic acid are used. It will be done. Among these, unsaturated polycarboxylic acids, especially maleic acid, fumaric acid, and itaconic acid, are important. Examples of alcohols to be esterified in partial esters of polybasic acids include saturated or unsaturated aliphatic alcohols having 1 to 18 carbon atoms, cyclohexanol, benzyl alcohol, and the like.
Among these, saturated aliphatic monohydric alcohols having 1 or more carbon atoms, and especially 3 or more carbon atoms, are particularly preferred. Examples of partial salts of polybasic acids include sodium salts, potassium salts, lithium salts, ammonium salts, amine salts, and alkanolamine salts. The blending ratio of the polybasic acid partial ester salt to polyvinyl alcohol is preferably 0.01 to 30 parts by weight per 100 parts by weight of the former.If the latter ratio is too small, the effect of preventing adhesion to the roll will be insufficient; If the latter ratio is too large, there is a disadvantage that the paper strength increasing effect becomes small. The method of mixing polyvinyl alcohol and polybasic acid partial ester salt is not particularly limited, and is arbitrary, such as adding one to an aqueous solution of the other, mixing both as powders, or mixing both as an aqueous solution. method will be adopted. The paper is treated with an aqueous solution containing polyvinyl alcohol and a polybasic acid partial ester salt. At this time, the concentration of polyvinyl alcohol in the aqueous solution is not particularly limited, but it is practical to set it to about 0.1 to 10% by weight. It should be noted that there is no particular problem in using polyvinyl alcohol together with other polymer components such as starches and polyacrylamide resins, and other additives such as latex, fillers, pigments, dyes, waterproofing agents, waterproofing agents, etc. Rust agents, antifoaming agents, surfactants, plasticizers, organic solvents, thixotropic agents, and the like may be added as appropriate. Examples of the treatment include size press coating and surface coating using a calender roll. Next, the paper processing agent of the present invention will be further explained by giving an example. Hereinafter, the term "%" refers to % by weight unless otherwise specified. Example 1 An aqueous solution was prepared consisting of polyvinyl alcohol with a degree of polymerization of 1700 and a degree of saponification of 99.9 mol%, 4% sodium salt of mono-2-ethylhexyl maleate, 0.08% water, and the remainder. Soak a 4cm x 11cm dry cloth in this aqueous solution,
It was attached to an iron roll heated to 90°C, dried for 10 minutes, and then peeled off at a speed of 2 m/min. The peel resistance was measured to be 87 g/cm as an average of 10 times, and there was almost no stain on the roll surface at the peeled area. Next, using a Dixon coater, the above aqueous solution was coated on the surface of a corrugated board liner with an outer diameter of 10 cm at a wet weight of 10 g/ ^m2 using a bar coating method.
The sample was continuously brought into contact with an iron heating roll (temperature 110°C) at a speed of 3 min/min. As shown in Table 1, almost no staining of the roll was observed even after 6 hours of continuous operation. Example 2 An experiment similar to Example 1 was carried out except that 0.2% of the sodium salt of mono-n-butyl maleate was used in place of 0.08% of the sodium salt of mono-2-ethylhexyl maleate. Control Example 1 Using only the 4% aqueous solution of polyvinyl alcohol used in Example 1 (that is, without adding the sodium salt of mono-2-ethylhexyl maleate in Example 1), an iron roll peeling test and a heated roll paper passing test were conducted. However, the results were extremely unsatisfactory. Control Examples 2 to 4 4% of the polyvinyl alcohol used in Control Example 1
Add polyoxyethylene lauryl ether (Control Example 2), polyoxyethylene nonylphenol ether (Control Example 3), and glycerin (Control Example 4) at a rate of 1% to polyvinyl alcohol to an aqueous solution. In addition, iron roll peeling tests and heated roll paper passing tests were conducted, but as shown in Table 1, satisfactory results were not necessarily obtained. The results of Examples 1 to 2 and Control Examples 1 to 4 are shown in Table 1.

[Table] Examples 3 to 6 The same experiment as in Example 1 was conducted except that the following polybasic acid partial ester salt was used in place of the 0.08% sodium salt of mono-2-ethylhexyl maleate. The results are shown in Table 2. Example 3 Sodium salt of mono-2-ethylhexyl itaconate 0.12% Example 4 Ammonium salt of monoisobutyl fumarate
0.2% Example 5 Sodium salt of mono-2-ethylhexyl succinate 0.08% Example 6 Potassium salt of mono-n-butylglutarate
0.2%

[Table] Examples 7 to 9 The same experiment as in Example 1 was conducted except that the following polyvinyl alcohol was used. The results are shown in Table 3. Example 7 Polyvinyl alcohol with a degree of polymerization of 1400 and a degree of saponification of 98.0 mol% Example 8 Monomethyl maleate obtained by saponifying 99.0 mol% of the vinyl acetate component of a monomethyl maleate-vinyl acetate copolymer with a monomethyl maleate content of 3.0% Modified polyvinyl alcohol example 9 Sodium vinyl sulfonate modified polyvinyl alcohol obtained by saponifying 99.0 mol% of the vinyl acetate component of a sodium vinyl sulfonate vinyl acetate copolymer with a sodium vinyl sulfonate content of 2.0 mol%.

【table】

Claims (1)

[Scope of Claims] 1. A paper processing agent prepared by blending a polybasic acid partial ester salt with polyvinyl alcohol. 2. The paper processing agent according to claim 1, wherein the proportion of the polybasic acid partial ester salt is 0.01 to 30 parts by weight per 100 parts by weight of polyvinyl alcohol. 3. The paper treating agent according to claim 1, wherein the polybasic acid partial ester salt is a monoalkyl maleate salt. 4. The paper treating agent according to claim 3, wherein the alkyl group of the monoalkyl maleate salt has 3 or more carbon atoms.