JPS62299598A - Surface sizing agent of 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 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a paper sizing agent. For more details,
This invention relates to a paper sizing agent that provides high sizing and surface strength regardless of whether the base paper contains aluminum salt or is strained.

[Conventional technology]

In the field of paper manufacturing, advanced paper making technology and sizing technology are required due to the recent deterioration of the raw wood situation and tightening of wastewater regulations. That is, despite the tendency for pulp quality to deteriorate due to the deterioration of the raw wood situation, there is a need to maintain or improve the specified strength for paper manufacturing. Furthermore, along with the tendency for neutral paper making to suppress aluminum salts, which is exposed due to stricter wastewater regulations, there is a demand for imparting a high degree of sizing to improve writability and printability even in this neutral paper making. To be more specific, stricter wastewater regulations have increased the recycling rate of papermaking water, and at the same time, there has been a strong desire to increase the amount of cheap calcium carbonate used as a filler. There is a growing trend to reduce the amount of aluminum sulfate used and make paper with neutrality, and it has become necessary to provide high sizing even in this neutral papermaking.

In this regard, in the internal addition method in which various additives are added during the paper making process, the amount of additives that are fixed is usually around 60%, and the amount of additives that are fixed is 100% and does not exhibit the paper quality improvement function. Not only is its usage efficiency low (but there are also limits to how much paper quality can be improved).

Conventionally, in order to solve the above problems, a sizing agent consisting of an aqueous dispersion of a water-soluble polymer compound and petroleum resin latex or maleic acid polymer has been applied to improve surface strength and sizing. . Here, water-soluble polymers are those used primarily for the purpose of improving surface strength, and include modified starch, polyvinyl alcohol, carboxymethyl cellulose, polyacrylamide-based polymers, petroleum resin-based latex, and maleic acid-based polymers. is used for the purpose of increasing size.

[Problem that the invention seeks to solve]

However, the above-mentioned petroleum resin-based latex used for the purpose of improving sizing is mainly composed of an alkali salt of a modified petroleum resin obtained by adding an unsaturated carboxylic acid to petroleum resin, and the other above-mentioned maleic acid-based latex is It is an alkaline salt of a copolymer whose main components are an esterified product of maleic acid and an α-olefin hydrocarbon such as styrene, propylene or isobutylene. In this way, all of these are alkali salts of carboxylic acids, so if the base paper to be surface sized contains aluminum salts, the applied surface sizing agent will contain an alkali salt of the carboxylic acid. The aluminum salts in the paper react with each other and exert a size effect, but if aluminum sulfate is not used at all in the paper-making process, or if the paper is made in a neutral state using a small amount of aluminum sulfate, Surface sizing agents containing these alkali salts of carboxylic acids exhibit little sizing effect.

Furthermore, these petroleum resin-based latexes and maleic acid-based polymers have the disadvantage that when used as an aqueous dispersion with the above-mentioned water-soluble polymer compound, the surface strength improving effect of the water-soluble polymer compound is reduced. There is.

Thus, there has been no known surface sizing agent that can provide high surface strength and sizing regardless of the presence of aluminum salt in the paper, and there has been a strong demand for the development of such a surface sizing agent.

In addition, an aqueous dispersion of a polymer latex and a water-soluble polymer compound in which the proportion of ethylenically unsaturated carboxylic acid in the total copolymer component is limited is known as a solution to the above problem (Japanese Patent Application Laid-Open No. 1983-1989). 66197), but the size is still insufficient.

[Means for solving problems]

As a result of intensive research to solve the above-mentioned problems, the present inventors have developed an aqueous mixture of a polymer latex obtained by copolymerization under specific conditions and a water-soluble polymer compound in a specific ratio. We have discovered that a surface sizing agent that satisfies this need.

That is, in the present invention, the proportion of the fluorine-containing ethylene monomer component in the total copolymer component is 3 to 50% by weight, and the solid weight ratio of the polymer latex to the water-soluble polymer compound is 1:9.
This is a paper surface sizing agent consisting of an aqueous dispersion having a ratio of 9 to 50:50.

The fluorine-containing ethylene monomer component in the present invention is 3 to 50
Polymer latex in terms of weight percent refers to 3 to 50 weight percent of polymer components such as SBR latex, MBR latex, MSBR latex, ethylene-vinyl acetate copolymer latex, and acrylic copolymer latex containing fluorine-containing ethylene. This is a latex substituted with monomers.

Here, the fluorine-containing ethylene monomer component refers to hexafluorobutyl (meth)acrylate, pentadecafluorooctyl (meth)acrylate, N-(n-propyl)-
N-(β-acryloxyloethyl)-perfluorooctane sulfonamide, hexafluorobutyl (meth)acrylate, heptadecafluorooctylethyl (meth)acrylate, hexafluoropropyl (meth)acrylate, hexafluorobutoxy (meth)acrylate , 2-hexafluorobutoxyethyl (meth)acrylate, 5-hexafluorobutoxyethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate,
A polymerizable vinyl-based polymer containing dodecafluorohebutyl (meth)acrylate, hexadecafluorononyl (meth)acrylate, and fluorine, which may be used alone or in combination of two or more. You can also do that. If these fluorine-containing ethylene monomer components are less than 3% by weight of the total polymer latex components, the sizing degree of the surface-sized paper will be insufficiently improved, and the fluorine-containing ethylene monomer components will not be sufficient. If it exceeds 50% by weight, water and oil repellency will be imparted to the surface-sized paper, making it unfavorable for printability, and when the surface-sized paper is used as a coated base paper, repellency of the coating color may occur. It occurs and is not desirable.

The preferred amount of the fluorine-containing ethylene monomer component is 5 to 40% by weight based on the total polymer latex component.

In addition to the above-mentioned fluorine-containing ethylene-based monomer component, the polymer latex used in the present invention includes, for example, styrene and butadiene in the case where the constituent components of SBR latex are replaced, and styrene and butadiene which are substituted with the constituent components of MBR latex. methyl methacrylate and butadiene if M
When replacing the constituent components of SBR latex, methyl methacrylate, styrene and butadiene,
If the constituent components of the ethylene-vinyl acetate copolymer latex are replaced, ethylene and vinyl acetate are used as the main monomers, and if the constituent components of the acrylic copolymer latex are replaced, the main monomers are acrylic ester. In addition to the main monomer and the fluorine-containing ethylene monomer component of each polymer latex, one or more selected from the following monomers is used as a high-order copolymer. It is used as a coalescing component and may modify the respective polymer latexes. In other words, the higher-order copolymerized monomers include conjugated diolefins such as butadiene, isoprene, and chloroprene, and aromatic compounds such as styrene and methylstyrene. group vinyl compounds, methacrylic esters such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate, acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, acrylonitrile, and methacrylonitrile. Ethylene-based nitrile compounds such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide,
These include hydrophilic monomers such as N-butoxymethylacrylamide, glycidyl acrylate, and glycidyl methacrylate. However, these are just examples, and any monomer copolymerizable with the main monomer of the polymer latex can be used.

The water-soluble polymer compounds used in the present invention include oxidized starch, modified starch such as enzymatically decomposed starch, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, and acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, and acrylonitrile. , a copolymer of one or two vinyl monomers such as styrene and an acrylamide monomer, and an acrylamide-based polymer such as an acrylamide homopolymer. can also be used in combination of two or more types. Note that it is desirable to use modified starch in combination with other water-soluble polymer compounds.

In the present invention, the preparation of the aqueous mixture from the polymer latex and the water-soluble polymer compound is carried out in order to avoid difficulty in recovering waste paper and to obtain surface sized paper with an appropriate degree of sizing. The water-soluble polymer compound is mixed in a solid weight ratio of 1:99 to 50:50, preferably 2:98 to 1 (h90).The blending ratio of polymer latex is 50111% (solid content) If it exceeds 1% by weight, it becomes extremely difficult to recover waste paper.On the other hand, if the proportion is less than 1% by weight, it becomes impossible to obtain an appropriate size.

The sizing agent comprising an aqueous dispersion of a polymer latex and a water-soluble polymer compound according to the present invention is used in the sizing/pressing process of the papermaking process, and is usually
It has a solids concentration of ~20% by weight, preferably 3~10% by weight, and is size-pressed into base paper in the form of an aqueous dispersion. The amount of application at that time is usually 0.5 to 2.5 solid g/n
(It is said to be about (one side).

The aqueous dispersion of the sizing agent according to the present invention can be obtained, for example, by dispersing the polymer latex of the present invention and a water-soluble polymer compound in pressurized and heated water (for example, JP-A-51 -Refer to Publication No. 62890, etc.),
According to another method, a polymer latex can be obtained by dispersing in water a finely ground polymer latex using surface activity rules or a water-soluble polymer compound such as polyvinyl alcohol. The size of the polymer latex particles in the aqueous dispersion is not limited, but may be generally 0.01 to 50 microns, preferably 0.05 to 2 microns.

〔Example〕

Examples are shown below to explain the present invention in more detail, but the present invention is not limited in any way by these Examples.

Note that the following percentages are based on weight unless otherwise specified.

Example 1 60% styrene, 24.5% butadiene, N-(n
-Propyl'') -N-(β-acryloxyethyl)-barfluorooctanesulfonamide 1.4χ, acrylic acid 1.5χ Fluorine-containing SBR latex with solid content of 50%; methyl methacrylate 62%, butadiene 25%
, heptadecafluorooctylethyl acrylate 10
%, Itacon #1. Fluorine-containing MBR Latinx with a solid content of 50% consisting of Ox; fluorine-containing with a solid content of 50% consisting of 30% styrene, 30% methyl methacrylate, 20% butadiene, 18.5% tetrafluoropropyl acrylate, and 1°5x acrylic acid. MSBR latex: ethylene 2
Fluorine-containing ethylene-vinyl acetate copolymer latex with a solid content of 50%, consisting of 0% vinyl acetate, 60% vinyl acetate, and 20% trifluoroethyl acrylate; 25% styrene, 10% methyl methacrylate, 43% butyl acrylate, octafluoro Propyl acrylate 15%, methacrylic acid-
Each polymer latex, a fluorine-containing acrylic copolymer latex with a solid content of 45%, consisting of 2% β-hydroxyethyl, 2% methacrylic acid, and 3% acrylamide, was produced by a known method and diluted with city water. 5 of the solid content lO%
A polymer latex dilution of the seeds was obtained.

On the other hand, 900 parts of city water was added to 100 parts of oxidized corn starch to obtain a 10% by weight starch paste paste which was heated and boiled. Furthermore, with a 10% by weight aqueous solution of fully saponified polyvinyl alcohol with a degree of polymerization of 1700 and a Pulckfield viscometer, the
Liquid viscosity measured at °C is 10% by weight of 160 centiboise
An aqueous polyacrylamide solution was obtained.

As shown in Table 1, the above 5 types of polymer latex and 3 types of water-soluble polymer compounds with a solid content of 10% by weight are blended together, and city water is added to the solid content. Sample of 5% by weight aqueous dispersion (sample 11kll ~
6) was obtained. A sizeless neutral paper base paper made by adding the following filler (Note 2) to the subcontracted pulp (Note 1) is immersed in each sample of these aqueous dispersions, and immediately squeezed, and the excess aqueous mixture is removed using a roll. , rotary drum dryer (110℃
, 3 minutes). For comparison, a commercially available fluorine-free acrylic copolymer latex with a solid content of 45% was obtained by the same manufacturing method as that used in the production of the fluorine-containing acrylic copolymer latex, except that octafluoropropyl acrylate was not used. Comparative samples were prepared by blending petroleum resin-based latex and a commercially available maleic acid-based polymer surface sizing agent with a water-soluble polymer compound as shown in Table 1.
．． 8 and 9, surface sizing was performed under the same conditions as when using Samples 1 to 6 of the present invention. Furthermore, for comparison, the surface size of an aqueous dispersion (sample m1o) in which the ratio of the polymer latex of the present invention to the water-soluble polymer compound exceeds 50,750 in terms of solid weight ratio and the amount of polymer latex is increased is as follows. Examples are also shown in the same table. These surface-sized papers were seasoned for 24 hours in a thermostatic chamber with a humidity of 65x and a temperature of 20°C, and then used for sizing, surface strength, and waste paper recovery tests. The conditions for making the sizeless neutral paper base paper used are as follows.

Note 1. Bulb; LBKP:NBXP-50:50 (weight) blended bar, each with a beating degree of 430cc.

Note 2. Filler: Kaolin clay 2ro for paper making has an ash content of 9.0
It was χ. Note that aluminum sulfate is not added.
Moreover, the basis weight was 65 g/-.

The sizing amount of the paper on which each sample of the aqueous dispersion was surface sized was 2.0 solid g (both sides)/rd. Table 2 shows the measurement results of the sizing degree, surface strength, and difficulty of recovering waste paper for these surface sized papers. The sizing was measured according to the Steckigt sizing test method specified in the JIS standard (P-8122), and the surface strength was R1.
Relative comparisons were made using a 10-point scale (1 point being the worst and 10 points being the best) using a printing suitability tester (manufactured by Mei Seisakusho). In addition, the difficulty level of waste paper collection is as follows:
JIS (P-8
209) It was put into a standard standard disintegrator and disintegrated for 15 minutes, and then a part of it was used to make paper using a square sheet machine, and after drying, it was visually observed.

Table 2 As is clear from the results shown in Table 2, when surface sizing was performed on base paper containing no aluminum salts, the surface sizing according to the present invention It can be seen that a higher degree of size and higher surface strength can be obtained while the waste paper is easily recovered compared to the conventional technology shown in .9). Furthermore, as shown in the test results of the surface size paper of the comparative example (sample m1Q), the blending ratio of polymer latex to water-soluble polymer compound exceeds the 50:50 (solid weight ratio) of the present invention. It is clear that if the amount of water increases, it will be difficult to recover the water.

Example 2 In place of the sizeless neutral base paper in Example 1, aluminum sulfate was added at 3.0x to the valve, and the amount of filler added was changed to 18%/pulp, and the ash content in the paper was changed from Example 1. The sample was exactly the same as Example 1 except that size-free acidic base paper was used (Nal ~ 10).
Surface size paper was obtained under the following conditions and the same performance evaluation was performed. The results are shown in Table 3.

Table 3 As is clear from Table 3, for the acidic paper containing aluminum salt, the surface size paper of Sample Fish 7 and 8 of the comparison example was the same as that of Example 1 without Fluminiram salt. It can be seen that although this is an improvement compared to when surface sizing is applied to rough paper, the surface strength is decreased. In other words, as is clear from the comparison of Examples 1 and 2, the performance of conventional sizing agents is greatly influenced by whether or not the base paper contains aluminum salts, and even when the base paper contains aluminum salts, Surface strength improvement is insufficient. In addition, 11&L9 paper surface-sized with a composition consisting of fluorine-free acrylic copolymer latex and polyvinyl alcohol has favorable results in terms of strength and waste paper recovery, but has a low degree of sizing. It is clear that when using a sizing agent, high sizing and surface strength can be obtained, and waste paper recovery is easy, regardless of whether or not the base paper contains aluminum salt. be.

Example 3 Styrene to methyl methacrylate to hydroxyethyl methacrylate to itaconic acid in a weight ratio of 12:40:2:1
and N-(n-propyl)-N-(β-
acryloxyethyl)-perfluorooctyl sulfonic acid amide (ho, 99:1.97:3.9)
0:10.80: 20.70: 30.60:
A latex with a ratio of 40.50: 50.40: 60 was produced, a surface sizing test was conducted in the same manner as in Example 1, and a coating color solution was prepared to examine repellency of the coating solution when used as a coated base paper. The coating was applied using a metering bar coater, and the presence or absence of repellency was observed.

5. The composition of the coating liquid for surface sizing is 2 parts of latex, 33 parts of starch, 15 parts of polyacrylamide, and 50 parts of water using 10% solution of each. The coating color is clay (υW-90) 80 parts, heavy calcium carbonate (Sankyo Seifunyaku Niscalon NO-1500)
10 parts, light calcium carbonate (Okutama Kogyo Tama Pearl T
P-222H3) 10 parts, casein 8 parts, and SBR latex (Mitsui Toatsu Chemical Co., Ltd. Polylac 755) 12 solid parts, with a solid content of 40% and a viscosity of 105 centiboise at 25°C.

As is clear from Table 4, when the amount of fluorine-containing ethylene monomer in the latex is less than 3%, the degree of sizing is low;
If it exceeds 0%, coating color repellency will occur,
If a latex with a fluorine-containing ethylene monomer content of 3% or more and 50% or less is used, it will be an excellent surface sizing agent with high sizing and surface strength and no repelling of the coating color. it is obvious.

Claims (1)

[Claims] A surface sizing agent consisting of a polymer latex containing a fluorine-containing ethylene monomer as a copolymer component and an aqueous dispersion of a water-soluble polymer compound, wherein all of the fluorine-containing ethylene monomer in the polymer latex is The proportion in the copolymer component is 3 to 50% by weight, and the ratio of the polymer latex to the water-soluble polymer compound is 1:9 in terms of solid weight ratio.
A paper surface sizing agent characterized in that the ratio is 9 to 50:50.