JPH06299500A - Neutralized paper and its production - Google Patents

Abstract

PURPOSE:To obtain neutralized paper capable of developing stable sizing proper ties. CONSTITUTION:This neutralized paper is produced by adding 0.25-0.75wt.% of an anionic emulsion type rosin sizing agent obtained by emulsifying rosin or its modified material with protective colloid consisting of a water-soluble high polymer to pulp, adding 1.0wt.% calcium carbonate as a filler to pulp and 1.0-2.0wt.% aluminum sulfate to pulp and further adding aluminum sulfate in multistages before or after adding the emulsion-type rosin size agent so that an amount of aluminum sulfate added after addition of the emulsion type rosin sizing agent may become >=50% based on total addition amount of aluminum sulfate in order to stably exhibit sizing property. Thereby, in the neutralized paper system containing the emulsion type rosin sizing agent and calcium carbonate, raw paper having stable sizing property is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a neutral paper using a rosin sizing agent and calcium carbonate as a filler and a method for producing the same, and particularly to a neutral paper using an anionic emulsion type rosin sizing agent as a sizing agent. The present invention relates to paper and a manufacturing method thereof.

[0002]

2. Description of the Related Art Rosin-based paper sizing agents have been widely used as paper sizing agents, and a sulfuric acid band has been used as an auxiliary agent. In this sizing agent, when the sulfuric acid band dissociates, it becomes acidic, so the paper sized in this system is acidic. However, in recent years, the problem of acidic paper has come to the fore, and the movement to make paper with a neutral type is increasing. Therefore, it has become widespread to bring the pH of the papermaking system closer to neutral by reducing the amount of the sulfuric acid band used. At the same time, calcium carbonate has come to be used as a filler because it is inexpensive, has excellent opacity, has little wire abrasion during papermaking, and stabilizes the storability of paper. Has begun to move to.

On the other hand, the protection of forest resources and the environment has been called for, and in the paperboard field, the recovery rate of waste paper has reached 80% or more. In addition, in addition to the problem of paper waste discarded from offices, recycled paper using recovered waste paper is booming in the field of high-quality paper. Along with that, the amount of calcium carbonate in used paper is increasing. As described above, this increase is brought about by an increase in the use of alkaline paper such as high-quality paper using calcium carbonate as a filler and an increase in the number of coated paper coated with a paint containing calcium carbonate.

When recycled paper is made from recovered waste paper containing calcium carbonate, it is necessary to adjust the pH to around 4.5 to 5 in order to effectively use the acidic size. There is a problem of need. Furthermore, since the calcium carbonate content varies depending on the type of waste paper, the papermaking pH fluctuates, and the size effect is not stable. On the other hand, when it is desired to make paper with as little sulfuric acid band as possible, the papermaking pH often becomes 6 or more, and the conventional acidic size cannot obtain a sufficient size effect. Although it is attempted to use an alkali sizing agent under such papermaking conditions, there are problems such as papermaking system stains and increased chemical costs. As described above, both the conventional acidic sizing agent and the alkaline sizing agent have a problem in neutral papermaking at a pH of about 7 using recovered waste paper.

In response to such expansion and problems of neutral papermaking, rosin-based neutral sizing agents have recently been proposed. As one example thereof, those described in JP-A Nos. 54-11305, 60-161472 and 63-120198 are known. Further, regarding the papermaking method using the rosin-based neutral papermaking sizing agent,
There is JP-A-3-220396.

[0006]

However, even if these methods are used, when calcium carbonate is actually used as a filler or the amount of calcium carbonate from the recovered raw material in the papermaking system becomes large, In many cases, sufficient size cannot be expressed. In particular, this tendency becomes remarkable when the water temperature in the papermaking system rises in the summer. Therefore, it is an object of the present inventors to provide a production method using an emulsion type rosin sizing agent and calcium carbonate as a filler.

[0007]

As a result of intensive studies to solve the above problems, the present inventors have invented the neutral paper of the present invention. That is, the neutral paper of the present invention comprises calcium carbonate as a filler, an anionic emulsion type rosin sizing agent obtained by emulsifying rosin or its modified product as a sizing agent with a protective colloid consisting of a water-soluble polymer, and a sulfuric acid band. Neutral paper, 0.25 to 0.75% by weight of the rosin sizing agent and at least 1.0% by weight or more of the calcium carbonate are added to the pulp, and 1.0 to 2. It is characterized by being made into paper by adding a 0% by weight sulfuric acid band.

Further, the method for producing neutral paper of the present invention comprises an anionic emulsion type rosin sizing agent obtained by emulsifying calcium carbonate as a filler, rosin or a modified product thereof as a sizing agent with a protective colloid composed of a water-soluble polymer, and sulfuric acid. Using a band, adding 0.25 to 0.75% by weight of the rosin sizing agent to the pulp and at least 1.0% by weight or more of the calcium carbonate in the pulp slurry, and 1.0 to the pulp. It is characterized in that a sulfuric acid band of up to 2.0% by weight is added in multiple stages and at least the amount of the sulfuric acid band added after the addition of the rosin sizing agent is 50% or more of the total amount of the sulfuric acid band added. .

Recent emulsion type rosin sizing agents are
Anionic emulsion type rosin sizing agent and JP-A-3-
A cationic emulsion type rosin sizing agent is known for the purpose of reducing the amount of band used and efficiently self-fixing on pulp fibers as disclosed in Japanese Patent No. 294596. A papermaking method using a cationic emulsion type rosin sizing agent as disclosed in JP-A-220396 is known. However, in any case, it is necessary to add more sulfuric acid bands to the papermaking system than the amount of sulfuric acid bands used in the papermaking system using a non-rosin-based sizing agent. Does not produce an effect. Regarding the function of the sulfate band in rosin-based sizing agents, several books (Pulp
and Paper) and the like, but it is said that its main function is to act as a precipitating agent, a retention aid, and also as a sizing agent. However, when calcium carbonate is used as a filler or when calcium carbonate is mixed in from waste paper, etc., the sulfuric acid band reacts with calcium carbonate, fixing the emulsion type rosin sizing agent and a complex having a hydrophobic property with the sulfuric acid band. Cannot be formed on the pulp fiber.

On the other hand, regarding the relationship between the emulsion type rosin sizing agent and the calcium carbonate in the system, the addition of calcium carbonate causes the pH in the papermaking system to become alkaline, and further the liquid temperature in the system to rise. When it comes, the rosin size begins to melt in the system, and it does not settle on the pulp fiber so that sufficient size is not obtained, and the rosin size accumulates in the system, leading to the problem of so-called "foaming".

In order to solve the above problems, it is necessary to efficiently fix the emulsion type rosin size and the sulfuric acid band on the fiber in the papermaking system. Generally, in a neutral papermaking system using calcium carbonate as a filler,
Cationic polymers such as cationized starch are used from the viewpoint of improving the retention of chemicals in the papermaking system and strengthening the strength of the product.In such a system, although the detailed mechanism is unknown, anionic emulsions are used. It was found that the rosin-type sizing agent exhibits better sizing property than the cationic emulsion-type rosin sizing agent. Second, it has been found that sufficient emulsion rosin sizing is needed to react with the fibers in the slurry. A minimum of 0.25% rosin sizing agent is required for pulp to achieve sizing, 0.75%
Even if added above, the size performance is saturated, and if added excessively, the problem of "foaming" in the system becomes remarkable.

Next, the emulsion type rosin sizing agent is fixed to the fiber, and a sufficient amount of the sulfuric acid band is necessary for the emulsion type rosin sizing agent and the sulfuric acid band to react efficiently on the fiber. In the present invention, it was found that when the amount of the sulfuric acid band added was 1.0 to 2.0% by weight based on the pulp, the size was effectively developed. When the addition amount of the sulfuric acid band is 1.0% by weight or less based on the pulp, sufficient sulfuric acid band does not exist in the system, so that sufficient size property cannot be obtained. Further, even if the addition amount of the sulfuric acid band was 2.0% by weight or more with respect to the pulp, the effect of improving the sizing property was saturated, and the sizing property tended to deteriorate rather. Furthermore, the addition of excess sulfuric acid band unnecessarily lowers the pH in the system, and causes decarboxylation of calcium carbonate in a part of the preparation process.

Furthermore, as a result of investigating the method of adding the sulfuric acid band, the present inventors added the sulfuric acid band in multiple stages before and after adding the emulsion type rosin size, and added sulfuric acid after adding the emulsion type rosin size. By adjusting the amount of the band to 50 to 100% by weight of the total amount of the sulfuric acid band added, at least 1.0 is added to the pulp.
It has been found that a sufficient paper size can be exhibited in a neutral papermaking system containing calcium carbonate in an amount of not less than wt%. By adding the band in multiple stages, the contact time between the calcium carbonate and the band can be shortened as much as possible, and the band and the emulsion type rosin size can be efficiently adsorbed to the fiber, and the size property is improved. Therefore, the sizing property can be brought out by the minimum necessary amount of the emulsion-type sizing agent and the sulfuric acid band added, and the amount of dissolved rosin or dissolved calcium in the papermaking system which causes "foaming" can be suppressed.

The ratio of the amount of sulfuric acid band added before the addition of the emulsion type rosin sizing agent and the ratio of the amount of sulfuric acid band added after the addition of the emulsion type rosin sizing agent is
It can be appropriately changed depending on the amount of calcium carbonate in the papermaking system. However, when the amount of calcium carbonate increases, it is effective to increase the ratio of the amount of sulfuric acid band added after the addition of the emulsion type rosin sizing agent. Desirably, the amount of the sulfuric acid band added after the addition of the emulsion type rosin sizing agent is 50% or more of the total amount of the sulfuric acid band added. When the amount of the sulfuric acid band added after the addition of the emulsion type rosin sizing agent is 50% or less with respect to the total amount of the added sulfuric acid band, the above-mentioned effect is not clearly exhibited.

The base paper produced in the present invention can be used as high-quality paper such as electrophotographic transfer paper, information recording base paper such as pressure-sensitive recording paper and heat-sensitive recording paper, and coated base paper. It is possible.

The pulp used in the base paper of the present invention includes NBKP, LBKP, NBSP, LBSP, GP,
Examples include TMP and waste paper pulp. In use, several of them are mixed and used at a ratio according to the purpose.

The filler used in the present invention may be a silicate (kaolin, clay, bentonite, talc, etc.), titanium dioxide, etc. in addition to calcium carbonate. In addition to the emulsion type rosin sizing agent, an alkyd resin, a styrene acrylic resin, a styrene maleic acid resin, AKD, ASA and the like can be used together as the internally added size. Although a sulfuric acid band exists in the papermaking system as a size fixing agent, cationic starch, polyacrylamide, etc. are added to fix the rosin-sized emulsion to the fiber. Furthermore, as the paper-strengthening agent (internally or externally added), starch, CMC, P
VA, polyacrylamide, melamine resin, urea resin,
Known products such as epoxidized polyamine resin and polyethyleneimine can be used.

The surface of the base paper of the present invention can be coated with various modified starches such as oxidized starch and various polyvinyl alcohols. If necessary, styrene-acrylic acid, styrene-methacrylic acid, styrene- It is also possible to use a surface sizing agent composed of a copolymer such as maleic acid or olefin-maleic acid together. At the time of coating, a size press device, a roll coater, a bar coater, a blade coater, or the like can be used.

[0019]

[Function] An emulsion type rosin sizing agent obtained by emulsifying rosin or a modified product thereof with a protective colloid composed of a water-soluble polymer is added to the pulp in an amount of 0.25% by weight to 0.75% by weight,
1. Calcium carbonate as a filler at least with respect to pulp
0% by weight, and a sulfuric acid band was added to the pulp in the range of 1.0 to 2.
0% by weight of neutral paper, further adding a sulfuric acid band before and after adding the emulsion type rosin sizing agent, and the addition amount of the sulfuric acid band added after the addition of the emulsion type rosin size is the total addition of the sulfuric acid band. A method for producing the same, which is capable of exhibiting stable sizing by controlling the amount to be 50% or more.

[0020]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples. The present invention is not limited to the examples. All parts and% in the following are by weight.

Examples 1 to 6 and Comparative Examples 1 to 5 In Examples and Comparative Examples of the present invention, the papermaking width is 5000 m.
m, machine speed 800 m / min, using Fourdrinier paper machine, freeness 3
0.7 parts of cationic starch was added to 100 parts of a 7: 3 mixture by weight of LBKP and NBKP beaten to 60 ml.
Bands and emulsion type rosin sizes were added to a pulp slurry containing 10 parts of calcium carbonate under the conditions shown in Table 1, and oxidized starch (manufactured by Nissho, MS3800) was applied to a base paper produced under such conditions with a size press. 1.2 g
/ M ² applied, basis weight 64 g / m ² , density 0.75 g / cm
^3. Paper with a finishing water content of 5.0% was manufactured.

The sizing property of the base paper of the present invention is JISP81.
According to the Cobb method described in 40, the contact time between water and paper is 3
The measurement was performed at 0 seconds.

The evaluation of bubbles during the papermaking process of the electrophotographic transfer paper of the present invention includes 122 to 12 of "Foaming Trouble and Defoaming Technology Comprehensive Technical Data" published by the Management Development Center Publishing Department.
It was carried out according to the diffuser stone method described on page 3. Specifically, 1 in a graduated cylinder with an inner diameter of 48 mm
00 ml of white water is collected, a porous stone that can send air into the white water is put in the bottom of the graduated cylinder, and air is sent to the porous stone by a pump (KP-20 type powerful pump made by Kinoshita Rika Kogyo) in the graduated cylinder. The mixture was forcibly bubbled for 5 minutes, and the volume of the bubble when the bubble reached the equilibrium point was measured and recorded.

[0024]

[Table 1]

As for the Cobb sizing degree, if the sizing degree is 30 g / m ² or less, it is considered that the sizing property is exhibited, and it is preferably 17 g / m ² or less. Regarding the foamability, it can be judged that there is no problem in actual operation if the foam volume is 80 ml or less in the above test method.

In Table 2, Examples 1 to 3 and Comparative Examples 1 to 1
Comparing 3 shows that the anionic rosin type emulsion sizing agent is effective. Furthermore, Examples 1 to 1
By comparing 3 with Examples 4 to 6, it can be seen that the size property can be improved by increasing the amount of the sulfuric acid band. However, by comparing Examples 2 and 5 with Comparative Examples 4 and 5, it can be seen that the optimum amount of the sulfuric acid band to be added is 1.0 to 2.0% by weight. On the other hand, Example 1, Example 4, Example 7 and Comparative Example 6,
By comparing Comparative Examples 7 and 8, it is necessary to use 0.25% by weight or more of the emulsion type rosin sizing agent in order to express the sizing property. By comparison, the amount of excess sizing agent "foams"
It turns out that Finally, by comparing Examples 1 to 3 with Examples 7 to 10, it is understood that the sizing property is improved by adding the sulfuric acid band in multiple stages before and after the addition of the emulsion type rosin sizing agent.

[0027]

INDUSTRIAL APPLICABILITY In the present invention, an emulsion type rosin sizing agent obtained by emulsifying a rosin or a modified product thereof with a protective colloid comprising a water-soluble polymer is used in an amount of 0.25% by weight based on pulp.
0.75% by weight, calcium carbonate as a filler is added at least 1.0% by weight with respect to the pulp, a sulfuric acid band is added with 1.0 to 2.0% by weight with respect to the pulp, and an emulsion type rosin sizing agent is further added. Sulfuric acid bands are added in multiple stages before and after addition, and the amount of sulfuric acid bands added after addition of emulsion type rosin size is 50% of the total amount of sulfuric acid bands added.
By the above, it was possible to provide a neutral paper capable of stably exhibiting size properties and a method for producing the same.

[Brief description of drawings]

FIG. 1 is a preparation flow when a sulfuric acid band is added in two stages.

FIG. 2 is a preparation flow when a sulfuric acid band is added in one step.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location D21H 17/65 7199-3B D21H 3/74

Claims (3)

[Claims] 1. A neutral paper comprising an anionic emulsion type rosin sizing agent obtained by emulsifying calcium carbonate as a filler, a rosin or a modified product thereof as a sizing agent with a protective colloid comprising a water-soluble polymer, and a sulfuric acid band. Neutral paper, the rosin sizing agent is 0.25 to 0.75% by weight with respect to the pulp, the calcium carbonate is at least 1.0% by weight or more, and the sulfuric acid band is 1.0 to with respect to the pulp. Neutral paper characterized by adding 2.0% by weight. 2. A method for producing a neutral paper, comprising using an emulsion type rosin sizing agent and a sulfuric acid band in which calcium carbonate is used as a filler, rosin or a modified product thereof is emulsified with a protective colloid consisting of a water-soluble polymer, The rosin sizing agent was added to the pulp in a pulp slurry at 0.
25 to 0.75% by weight, the calcium carbonate is at least 1.0% by weight or more, and the sulfuric acid band is added to the pulp in an amount of 1.0 to 2.0% by weight for papermaking. Manufacturing method. 3. A sulfuric acid band in multiple stages so that the amount of the sulfuric acid band added after the addition of the emulsion type rosin sizing agent according to claim 2 is 50% or more of the total amount of the sulfuric acid band added to the papermaking system. A method for producing neutral paper, which comprises adding.