JPS62111000A - Production of improved filled 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 [Industrial Application Field] The present invention relates to a method for manufacturing a filled paper, 1 and more particularly to a method for manufacturing a filled paper having a high degree of sheet strength and water absorption dimensional stability.

The filled paper obtained by the production method of the present invention has higher paper strength and water absorption dimensional stability than conventional filled paper, and can be used for wallpaper, sound insulation paper, insulating paper, flame retardant paper, gypsum board base paper, gasket paper, etc.
It can be used for a wide range of purposes, such as backing paper for floors, vibration damping materials, sound absorbing materials, base paper for roof ink, printing paper, various paperboards, and base paper for coatings. It can be suitably used in applications where filled paper with a high proportion of filler is used, such as paper, roof ink base paper, and gasket paper.

[Conventional technology]

Various methods for producing filled paper made of water-dispersible fibers, fillers, and polymer latex have been proposed at present. For example, Tokko Sho Fj-r/4! In the publication, a water-dispersible liquid latex O0j% consisting of an inorganic filler and a rut fiber is added,
A method has been proposed in which highly filled paper is produced by converting latex particles into giant suspended particles and then using a conventional papermaking method.

[Problem that the invention seeks to solve]

However, the filled paper obtained by this method has the drawbacks of not having sufficient paper strength and also having a low filler yield. The reason for this is thought to be that not only the amount of latex used is small, but also that the effective area that acts as a binder is extremely small because the paper is made by forming latex particles into giant suspended particles.

In addition, in Special Publication No. Shoj7-Hiroshi 9610,
ot;, amount of water-dispersible fiber and 60 to qsx*
A method for producing highly filled paper is disclosed, which involves colloidally destabilizing an aqueous dispersion consisting of filler S and 30% by weight of latex to form an aqueous suspension of fibrous aggregates. . However, this method does not control the fixation of latex particles to fibers or fillers at all, so the latex does not function well as a binder, and only filled paper with inferior paper strength and dimensional stability can be obtained. do not have.

Furthermore, Japanese Patent Application Laid-Open No. 9-30-1989 Tade No. 1 discloses that a filled paper with a filler content of from 0 to 50 wt. A manufacturing method using 0.5 to 20 weight liters of latex has been disclosed, but this method also does not give any consideration to the complete control of fixing the latex to the fibers and fillers, and it is difficult to obtain any benefits. The paper strength of the filled paper used is also not sufficient.

An object of the present invention is to provide a method for producing a filled paper having far higher paper strength and superior water absorption dimensional stability than those obtained by conventionally known methods.

[Means for solving problems]

In order to achieve the above objective, we investigated the method of fixing latex to fibers and fillers in the production of filled paper, and unexpectedly identified water-dispersible fibers and fillers whose main components are glass fibers and cellulose fibers. Glass fibers, cellulose fibers and fillers are dispersed in water in the presence of an amount of cationic material, mixed with anionic polymeric latex, and colloidally destabilized to produce glass fibers, cellulose fibers and fillers uniformly coated with latex particles. It has been found that a filled paper obtained by forming a suspension of fibrous aggregates containing fibrous agglomerates, paper making, and drying has a high degree of paper strength and water absorption dimensional stability, and the present invention has been achieved based on this finding.

That is, the present invention colloidally destabilizes an aqueous slurry consisting of a water-dispersible fiber 1 filler and a polymer latex to form a fibrous aggregate suspension, which is then processed into paper and dried to produce filled paper. In the method, glass fibers, cellulose fibers and fillers are dispersed in water in the presence of Q, 3 parts by weight to 3 parts by weight of a cationic substance based on 100 parts by weight of the raw material for filling paper, and then polymer latex is added. , the production of an improved filled paper characterized in that it is colloidally destabilized to form a fibrous aggregate suspension comprising glass fibers, cellulose fibers and fillers substantially uniformly coated with a latex polymer. It is about the method.

The type of glass fiber used in the present invention is one that is usually commercially available (chopped strand, cut length: about 3 to
j 1fil, fiber diameter: about several μ to 75 μ), and the amount used is from 1 to 10 parts by weight, preferably from 3 to 7 parts by weight. Glass fiber is used to improve the water absorption dimensional stability of the filled paper. If it is used in less than 2 parts by weight, the water absorption dimensional stability of the filled paper will be extremely poor, and if it exceeds 10 parts by weight, the surface smoothness of the filled paper will be deteriorated. becomes noticeably worse, which is not desirable.

The filled paper of the present invention requires the use of cellulose fibers in addition to glass fibers. As cellulose fiber,
One or more types of chemical pulps such as unbleached kraft pulp and bleached kraft pulp, synthetic wood pulp, and recycled waste paper can be used. The proportion of cellulose fiber used is λ to 70 parts by weight per 100 parts by weight of the packed paper compounding material.
FL parts by weight, preferably S to 30 parts by weight. 21
If the amount is less than 70 parts, the paper strength of the filled paper will be extremely reduced, and if it exceeds 70 parts, the water absorption dimensional stability will be extremely reduced, which is not preferable. In addition to glass fibers and cellulose fibers, synthetic fibers such as polyester fibers and nylon fibers, rock wool, carbon fibers, and ceramic fibers can also be used as required.

Examples of fillers used in the present invention include talc, titanium oxide, silica, zinc oxide, barium sulfate, diatomaceous earth, calcium sulfate, calcium oxide, carbonized calcium, aluminum hydroxide, magnesium hydroxide, clay, and mica. It will be done. The proportion of the filler used is 20 to 90 parts by weight, preferably 20 to 5 parts by weight. -0
If it is less than 95 parts by weight, the water absorption dimensional stability will be extremely low, and if it exceeds 95 parts by weight, the paper strength will be extremely reduced, which is not preferable.

Examples of the polymer latex used in the present invention include butadiene-based copolymer latex, isoprene-based copolymer latex, and isoprene-based Latex and diene polymer latex such as chloroprene latex are preferred. But it’s a must! 1) Ethylene-vinyl acetate latex, vinyl acetate latex, acrylic latex, etc. can also be used depending on K.

The proportion of polymer latex used is 700% of the filling paper compounding raw material.
Based on parts by weight, it is from 2 to 30 parts by weight, preferably from j to 25 parts by weight. If it is less than 2 parts by weight, the paper strength and water absorption dimensional stability of the filled paper will be poor, and if it exceeds 30 parts by weight, a large amount of flocculant will be required to colloidally destabilize the water-repellent slurry, which is not preferable. .

The improved filled paper manufacturing method of the present invention involves treating the fibers and fillers with a specific amount of cationic material, then adding polymeric latex, and using glass fibers, cellulose fibers, which are almost uniformly coated with the latex polymer. , is characterized in that it forms a fibrous aggregate suspension containing a filler. When glass fibers, cellulose fibers, and fillers are hardly coated with high-molecular latex polymers, the resulting filled paper has low paper strength and water absorption dimensional stability, and
Glass fibers, which cause skin irritation (tingling) to the human body, tend to be easily detached from the filling paper, which is undesirable.

In addition, in the present invention, it is necessary to add the polymer latex after treating the fibers and filler with a cationic substance, but before adding the filler in order to preferentially attach the latex polymer only to the fibers. The addition of some latex will not detract from the invention, but if the entire amount of latex is added before adding the filler, the fibers will be less likely to be coated with the latex polymer and will have a high paper strength. Filled paper with strength and water absorption and dimensional stability cannot be obtained.

Although Vi is not particularly limited as a cationic substance, the molecule t
Cationic organic compounds such as polyamine-based polymers having a molecular weight of 20,000 to 0,000, polyamide-epichlorohydrin resins, polyethyleneimine, cationic starches, cationic emulsifiers, and cationic molecule latexes can be suitably used. The amount of cationic substance used varies depending on the type of cationic substance, the type and amount of polymer latex used, the amount of fiber mixed, etc.
filler and polymer latex) 0.3 parts by weight to 311 L per 100 parts by weight, particularly preferably 0.8 parts by weight
It is suitable to use 5 parts by weight to 2.0 parts by weight. 0#
If the amount is less than M parts, it will be difficult for the latex polymer to adhere uniformly to glass fibers, cellulose fibers, and fillers, resulting in poor paper strength and water absorption dimensional stability. The latex polymer adheres uniformly to the fibers and filler, resulting in low strength and poor water absorption dimensional stability of the filled paper, as well as the formation of a fibrous aggregate suspension, which reduces yield. A book with a low value is not desirable. To check whether the fibers and fillers are uniformly coated with latex polymer, take a part of the fibrous aggregate suspension, treat it with osmic acid, dry it at room temperature, and then observe it with a scanning electron microscope. It can be judged by this.

The manufacturing method of the present invention requires colloidal destabilization of an aqueous slurry of fibers, fillers, and polymeric latex to form a fibrous aggregate suspension. Methods for colloidal destabilization include methods using stirring or temperature changes, and methods by adding a flocculant to coagulate the latex, but the method of adding a flocculant provides more reproducible results. It is preferable.

Examples of flocculants include polyvalent inorganic electrolytes such as aluminum sulfate, alum, calcium chloride, and magnesium chloride, cationic water-soluble polymers, anionic water-soluble polymers, nonionic water-soluble polymers, cationic latex, anionic latex, etc. However, in the present invention, it is preferable to use a cationic flocculant and an anionic flocculant in combination because it provides a high filler yield.

Chemicals commonly used in the paper industry in carrying out this invention, such as cellulose derivatives, anti-aging agents, water-soluble organic dyes, water-dispersible color pigments, starch, non-ionic acrylamide copolymers, melamine-formaldehyde resins. , crosslinkable resins such as epoxy resins, paper strength agents, and sizing agents such as alkylcatenium dimer/wax emulsions and rosin may also be used as necessary.

〔Example〕

The present invention will be explained in more detail below with reference to Examples, and all parts in the Examples and Comparative Examples refer to the important parts.

Example/ 70 parts of bleached kraft pulp (softwood) was beaten with 5 parts of glass fiber (length 3 + 1111. diameter 6μ) in a beating machine, and the Canadian freeness of the pulp (JISPI/2/
) is adjusted to 300m1 VC null j.

Next, the concentration of the water slurry was reduced to 0. #%, add 0.0 parts of a polyamine-based cationic polymer (molecular weight: 10,000, cationicity: 10 meq/litre) while stirring, and then add 35 parts of Merck and 3r parts of Kei-no-shi. and continued stirring for 5 minutes. and 72 parts of medium texture styrene-butadiene latex (L1) rs3:
Asahi Kasei Co., Ltd. ■) and 3 parts of hard type styrene peptadiene/based latex (L12.3r: Asahi Kasei Co., Ltd. ■11) were added, and finally a cationic coagulant (KP/I T, manufactured by Diafloc Co., Ltd.) 0 , v part and anionic flocculant (
0.03 part of Diafloc AP4'#) was added to form a fibrous aggregate suspension. Transfer the aqueous dispersion obtained in this way to a square sheet man, add water and
．． The slurry concentration was adjusted to 1%, water was drained, wet paper was obtained, wet pressed, and then dried in a drum dryer to produce filled paper. When a portion of the aggregate suspension was taken out and observed under a scanning electron microscope, it was found that the surfaces of the glass fibers, cellulose fibers, and filler were uniformly coated with latex particles.

The paper strength and water absorption dimensional stability of the obtained filled paper were measured.

Paper strength: Filled paper /,! ; It was cut into strips with a width of cn1, and the breaking strength was measured when 2 parts were pulled at a speed of 1 minute using a tensile 9 tester.

Water absorption dimensional stability: sample (length 2 Q cm, width 3 cm
m+) was washed and immersed in water for 2 hours, and then the elongation in the longitudinal direction was measured.

The measurement results are shown in Table/.

Example 2 ~ ψ Filling of Example 2 ~ tI in the same manner as in Example/, except that the type and blending ratio of the cationic substance, the blending ratio of glass fiber, filler, and latex were changed as shown in Table 7. Paper was obtained, and the physical properties of the paper were measured in the same manner as in Example. The results are shown in Table/.

Comparative Examples/~3 Corresponding to Examples 3 and 3, except that the types and blending amounts of fibers, fillers, and latex were the same, and only the amount of cationic substances used was outside the range of the present invention. Filled paper of Comparative Example/~3 as shown in Table 7 was obtained in a similar manner,
Physical properties were measured. However, in comparative examples/2, the flocculant used to form the aggregate suspension was a cationic substance (KP).
154 T) was sufficient.

From the results in Table 1, it is clear that the filled paper obtained using a cationic substance at a level that allows the surfaces of glass fibers, cellulose fibers, and fillers to be uniformly covered with latex particles is more clearly than the filled paper shown in the comparative example. Comparative Example 1 Filled paper was obtained in the same manner as in Example except that latex was added before the filler was added. . Example of this result/
A comparison is shown in the table. Table 2: Unlike the present invention, the paper obtained by treating only the fibers with a cationic substance, adding latex, and then adding filler clearly has considerably lower paper strength and water absorption dimensional stability. I understand.

Comparative Example sNr As shown in Table 3, when the amount of K, glass fiber used is very small, the amount of pulp or filler used is very large or small, and the amount of polymer latex used is very small. Filled paper was prepared in the same manner as in Example 7, except that the amount was reduced, and its physical properties were measured. Table 3 shows the results.
Shown below. From the results in Table 3, it can be seen that the amount of glass n1 miscellaneous used was small9, when the amount of pulp used was very high, the water absorption dimensional stability of the filled paper was noticeably poor, and the amount of paper filler used was very high. It is clear that if Vi is too high or the amount of pulp used is very small, the strength of the filled paper will decrease significantly.

(Margin below) 〔Effect of the invention〕

Claims (1)

[Claims] (1) A method of producing filled paper by colloidally destabilizing an aqueous slurry consisting of glass fibers, cellulose fibers, fillers, and polymer latex to form a fibrous aggregate suspension, followed by papermaking and drying. In this step, glass fibers, cellulose fibers, and fillers are dispersed in water in the presence of 0.3 parts by weight to 3 parts by weight of a cationic substance based on 100 parts by weight of the raw materials for filling paper, and then polymer latex is added. , the production of an improved filled paper characterized in that it is colloidally destabilized to form a fibrous aggregate suspension consisting of cellulose fibers, glass fibers and fillers substantially uniformly coated with a latex polymer. Method.