JP2739799B2 - Unbleached kraft paper for heavy sack base paper and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a method of manufacturing the same processed by heavy bag unbleached kraft paper for base paper used and the heavy bags bag making factory, if described in further detail, the contents after printing and bag making TECHNICAL FIELD The present invention relates to unbleached kraft paper for heavy sack base paper which hardly causes so-called heavy sack sliding trouble which occurs when loading or transporting a bag filled with articles, and a method for producing the same.

[0002]

2. Description of the Related Art In the powder manufacturing industries such as the milling industry, the sugar industry, and the chemicals manufacturing industry, a powder product is filled in a heavy bag made of unbleached kraft paper, and this is filled with several layers. They are also stacked and stored, or stacked on a pallet, loaded, transported by a forklift, loaded on a truck, and shipped. When the heavy bags filled with the powder products are stacked in this way, if the surfaces of the bags are slippery, the stacked bags slide down and the efficiency of the transfer operation is greatly reduced. If the bag is broken by the impact of the drop, the powder product filled in the heavy bag is scattered and cannot be collected, resulting in a large loss. Sliding falls are likely to occur when a forklift or truck makes a curve or suddenly stops, and if there is a person at the place where the forklift or truck is dropped, it may be a fatal accident. The problem of slippage of heavy bags is a very serious problem that leads not only to a decrease in productivity but also to a major accident, and is a quality issue for not only users of heavy bags but also bag makers and paper makers. Therefore, there is a strong demand for a non-slip heavy sack base paper which maintains the bag making workability and the quality after bag making.

[0003] However, unbleached kraft paper used as a heavy sack base paper has very many opportunities to become slippery due to physical surface friction and chemical component adhesion in printing, bag making and transporting processes. For example, in a bag making factory that manufactures heavy bags from unbleached kraft paper, the base paper is printed on its surface with a product name, etc., and then sent to a bag making machine to be folded, glued, cut, and bottomed. It is made into a heavy bag after processing such as pasting and sewing, but in the printing and processing, many rolls are arranged to change the running direction of the base paper unwound from winding, and as a result, the surface of the base paper is It is rubbed and becomes slippery. In addition, ordinary printing inks contain polyethylene etc. for the purpose of smoothing the printed surface after drying and protecting the printed surface.In the case of oil-based inks, the vehicle penetrates the paper. It becomes slippery.
In the heavy bag transporting process, the transport operation has been automated due to the spread of unloading conveyors such as roller conveyors and palletizers. As a result, the continuous heavy bag flow has occurred, and the chances of the surface of the bag being rubbed are increasing.

[0004] In order to make the surface of base paper used for heavy bags less slippery, the papermaking industry has conventionally applied or sprayed a commercial anti-slip agent on the base paper surface using a size press or a spray nozzle during the drying process in the base paper manufacturing stage. Various methods have been attempted. As a commercially available anti-slip agent, a colloidal silica-based inorganic substance, a styrene-acrylic polymer paste, or the like is mainly used. Also, in the bag making industry, there are many cases where one color of ink is mainly used for applying an anti-slip agent in a multicolor printing machine.
Further, an anti-slip agent is applied to the bag surface after the bag making.

[0005]

However, in the method of applying or spraying the anti-slip agent on the surface of the base paper in the drying step in the base paper manufacturing stage, the dirt on the dryer section is remarkable, and the anti-slipping agent adheres and accumulates on the paper making canvas or the dryer cylinder. There is a disadvantage that the commercial value of the base paper is lost if the stains that have been altered by heat are transferred to the base paper. In addition, since paper machines produce a very large variety of papers, if the anti-slip agent contamination generated during the production of heavy sack base paper mixes with high-quality varieties such as base paper for tape and paper for food use, papermaking As a result, credit will be lost. Further, in the case of a product in which a slip preventive agent is applied to one side of a base paper, there is a problem that it is completely meaningless if a bag maker manufactures the slip preventive agent coated surface inside the bag.

[0006] In addition, when printing on base paper, a method of applying an anti-slip agent with a printing machine involves applying the anti-slip agent in a very short time before and after ink transfer, so that it is not possible to apply the anti-slip agent on the most slippery printing surface. It can be applied only to the outside of the picture printing section or the back of the bag. Furthermore, the method of applying an anti-slip agent to the bag surface after bag making is inefficient because it is an operation for each bag.

Accordingly, an object of the present invention is to produce a heavy bag which is not slippery even when stacked after being filled with a powdered product, without applying an anti-slip agent to the surface of the base paper in a papermaking or bag making stage. Unbleached kraft paper for heavy bag base paper
And to provide a method for producing it.

[0008]

Means for Solving the Problems The present inventors have studied the above-mentioned problems of the prior art from the viewpoint of colloid chemistry and made intensive studies. As a result, the present inventors have found that a specific amount of hydrated silicate for papermaking having a specific particle size distribution can be obtained. Heavy bags made from unbleached kraft paper, which is internally added to the raw material of unbleached kraft paper as a filler,
It has been found that the powder product is less slippery when filled and stacked, and the present invention has been completed.

That is , the non-bleached kraft for heavy bag base paper of the present invention
Paper has a small particle ratio in the particle size range of 1 to 30 μm.
Is 80% by weight or more and the particle ratio is 70 μm or more.
0.4% by weight or less, and the average particle size is 5 to 10 μm.
m of filler made of paper hydrated silicate in the range of
0.2 to 3% by weight per pulp
Things. Furthermore, in the method for producing unbleached kraft paper for heavy sack base paper of the present invention, the ratio of particles having a particle size of 1 to 30 μm is at least 80% by weight, and the ratio of particles having a particle size of 70 μm or more is 0.4% by weight or less. A filler made of a hydrated silicate for papermaking having an average particle diameter in the range of 5 to 10 μm is internally added to the papermaking raw material of unbleached kraft paper in an amount of 0.2 to 3% by weight based on the dry pulp. It is characterized by the following.

The unbleached kraft paper thus obtained has a sliding inclination angle of 30 ° or more by JISP8147 at the base paper stage mainly due to the physical abrasion resistance of the internal filler, and even after printing and bag-making. As a result of the internal filler absorbing and retaining oil component stains transferred and attached from the ink and processing steps and preventing the stains from adhering to the cellulose surface, the slip inclination angle can be maintained at 25 degrees or more.

The slip angle after printing and bag making is affected by various factors such as the printing area, the type of ink, the type of processing machine, and the maintenance state of the processing machine. It has been empirically found that a trouble occurs. If the slip inclination angle can be kept at 25 degrees or more, no slip trouble occurs.

In the present invention, the mechanism by which the slip angle of the base paper is improved requires a consideration of surface chemistry. However, the improvement of the shear resistance by preventing the intermolecular cohesion on the base paper surface from decreasing and the improvement of the filler itself are required. It is considered that this is due to the improvement in the frictional resistance of the steel. That is, due to the surface area of the filler particles and the lipophilicity of the surface, the effect of preventing the suction force at the molecular level acting between the surfaces of the base paper from being reduced by dirt of the molecular film level, and the small indentation formed when the base paper surfaces come into contact with each other It is considered that the effect of increasing the frictional resistance of the filler itself depending on the portion provides resistance to the slip phenomenon.

In general, the slip angle of paper varies depending on the type of pulp used, fillers, chemicals added, and the surface properties of the paper.
In the case of the present invention, the type of filler to be added has the largest effect, and other factors are smaller than that. That is, in the present invention, the proportion of particles having a particle diameter of 1 to 30 μm is at least 80% by weight, the proportion of particles having a particle diameter of 70 μm or more is 0.4% by weight or less, preferably 0.05% by weight or less, and A filler made of a hydrated silicate for papermaking having an average particle size in the range of 5 to 10 μm is used. Particle size 1-3
When the particle ratio in the range of 0 μm is less than 80% by weight and the particle ratio of particles having a particle diameter of 70 μm or more is more than 0.4% by weight, the number of particles involved in anti-slip is remarkably reduced. Must be economical.

The hydrated silicate for papermaking having such a particle size distribution can be produced by reacting sodium silicate with a mineral acid and salts in an aqueous solution. This manufacturing method is described in, for example, Japanese Patent Publication No. 1-60183.

The filler is added in an amount of 0.2 to 3% by weight based on the absolutely dry pulp in the raw material of unbleached kraft paper. If the addition ratio exceeds 3% by weight, there is no significant effect on the increase of the slip inclination angle of the paper, so that the cost is increased and the strength of the obtained heavy sack base paper is reduced. Further, when the addition ratio is 0.1.
If it is less than 2% by weight, the desired effect of improving the inclination angle cannot be obtained.

The place where the filler is added to the papermaking raw material is not particularly limited, and other internal chemicals may be added to unbleached pulp raw material, oxygen-bleached pulp, waste paper raw material or white water after ordinary beating. Can be added in the same manner as described above. In consideration of the yield to paper, it is preferable to add a filler made of hydrated silicate for papermaking after neutralizing the pulp surface charge by adding a cationic retention aid such as a sulfate band to the papermaking raw material.

[0017]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples below, but the present invention is of course not limited thereto. In Examples and Comparative Examples,%
All parts and parts are by weight and parts by weight. The “slip inclination angle” in Examples and Comparative Examples is JISP81.
According to the tilt method specified in 47, the same sample was measured 10 times continuously, and the value after 10 times was defined as the slip tilt angle. The particle size distribution of the hydrated silicate was measured by a small-pore passage method (commonly called a Coulter counter method).

Example 1 As softwood, 50 parts of Douglas fir, 35 parts of domestic pine,
15 parts of Japanese cedar cypress are mixed to produce unbleached kraft pulp with a kappa value of 40, and the freeness is 58 with a refiner.
0c. s. f. (Canadian Standard Freeness), 0.2% of synthetic sizing agent, 1.0% of sulfuric acid band and 0.2% of acrylamide were added, and hydrated silicate for papermaking (particle ratio of 1 to 30 μm was 95%). %, Particles having a particle diameter of 70 μm or more, 0.1%, average particle diameter of 10 μm, produced by the method described in Japanese Patent Publication No. 1-60183) as a filler at a ratio of 2% based on absolutely dry pulp. And
Paper was used. Next, using the stock, a bell form former III type paper machine (manufactured by Mitsubishi Heavy Industries, Ltd.) is used to make a paper at a speed of 600 m / min. Production of unbleached kraft paper for ² heavy bag base paper, 1,010mm width x 6,000m
Four long windings were made. The slip inclination angle of this base paper was 32 degrees. This winding was subjected to printing and bag processing in a bag making factory, and used as an outer layer of a three-layer bag of 456 mm × 790 mm. The sliding inclination angle between the papers on the bag surface was 28 degrees. The bag was filled with 25 kg of sugar by a sugar company to produce a product, but no slipping trouble occurred.

Comparative Example 1 An unbleached kraft paper having a basis weight of 84 g / m ² was produced in the same manner as in Example 1 except that the hydrated silicate for papermaking was not added as a filler. Winding 4 of the same size
Created a book. The slip angle of this base paper was 25 degrees. This winding was used for printing and bag processing in the same manner as in Example 1. The sliding inclination angle between the papers on the bag surface was 20 degrees. A sugar company pointed out that there was no slip-fall problem, but it was slippery and difficult to handle.

Example 2 As softwood, 30 parts of Douglas fir, 35 parts of domestic pine,
Unbleached kraft pulp having a kappa number of 40 was manufactured by mixing 15 parts of Japanese cedar cypress, and 20 parts of deinked waste paper was further mixed with the pulp to obtain a freeness of 560 c. s. f.
After adjusting to 0.2% of synthetic sizing agent, 1.0% of sulfuric acid band
% And acrylamide 0.2% were added, and the same hydrated silicate for papermaking as in Example 1 was added as a filler at a ratio of 1% based on the absolutely dried pulp to obtain a paper stock. Then, base <br/> Le form foamer III type paper machine using this paper stock (manufactured by Mitsubishi Heavy Industries, Ltd.)
To produce unbleached kraft paper for heavy sack base paper having a basis weight of 84 g / m ^{2 and} a width of 1,110 mm ×
Two rolls of 6,000 m length were made. The slip inclination angle of this base paper was 31 degrees. This winding is printed and bag-processed in a bag making factory to make a 456 mm × 790 mm 2
Used for outer layer of layer bag. The sliding inclination angle between the papers on the bag surface was 27 degrees. This bag is made of resin 25 by a chemical company.
The product was filled with kg, but no sliding trouble occurred.

Comparative Example 2 Unbleached kraft paper having a basis weight of 90 g / m ² was prepared in the same manner as in Example 2 except that the hydrated silicate for papermaking was not added as a filler. Winding 2 of the same size
Created a book. The slip angle of this base paper was 24 degrees. This winding was used for printing and bag processing in the same manner as in Example 2. The slip angle of the paper on the surface of the bag was 18 degrees. A chemical company was pointed out that a sudden brake caused a slip and fall when transporting a forklift. Table 1 summarizes the above Examples and Comparative Examples.

[0022]

[0023]

As can be seen from the above description, according to the present invention, a hydrated silicate for papermaking having a specific particle size distribution is internally added to a papermaking raw material of unbleached kraft paper at a predetermined ratio to form a paper. The unbleached kraft paper for sack base paper can have a sliding inclination angle of 30 degrees or more at the base paper stage, and can maintain a sliding inclination angle after bag making of 25 degrees or more.

As a result, it is possible to prevent a slip-down accident which may occur when stacking and transporting the heavy bag products filled with the powder in the bags, and to safely transport the heavy bag products in the warehouse. The process can be performed smoothly, and the step of applying an anti-slip agent to the base paper or bag surface, which was conventionally performed during papermaking or bag making, can be omitted, greatly simplifying the base paper manufacturing process or bag making process. This has the effect that the conversion can be performed.

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Kenzo Kiyota 2-1-1 Hirosuehiro, Kure-shi, Hiroshima Oji Paper Co., Ltd. Kure Mill (56) References JP 1-60183 (JP, B2) Publication No. 56-18712 (JP, B2) Minoru Yoneya, Atsushi Nakanishi, Setsuzo Ota, “Printing Paper”, 2nd revised edition, Printing Society of Japan, September, 1972, p. 26-29

Claims (2)

(57) [Claims] 1. The method according to claim 1, wherein the proportion of particles having a particle diameter in the range of 1 to 30 μm is small.
At least 80% by weight and particle size of 70μm or more
Is 0.4% by weight or less and the average particle size is 5 to 1
A filler consisting of hydrated silicate for papermaking in the range of 0 μm,
0.2 to 3% by weight per bone dry pulp
Unbleached kraft paper for base paper. 2. The proportion of particles having a particle diameter of 1 to 30 μm is at least 80% by weight, the proportion of particles having a particle diameter of 70 μm or more is 0.4% by weight or less, and the average particle diameter is 5 to 1%.
A filler consisting of hydrated silicate for papermaking in the range of 0 μm,
0.2 ~ per dry pulp in unbleached kraft paper
A method for producing unbleached kraft paper for heavy sack base paper, comprising internally adding 3% by weight of paper.