JP3275059B2 - Manufacturing method of easily absorbed paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of easily absorbable paper having good printability, and is used for coasters, paper tablecloths, napkins and the like.

[0002]

2. Description of the Related Art Coasters are also called cup mounts.
Used in beer halls, coffee shops, restaurants, and homes as glass mounts for beer, juice, and wine. Because these beverages are stored at low temperatures, non-sized paperboard is used to easily absorb water in order to prevent water droplets condensed on the outer wall of the glass from flowing down and soiling the table . In addition, paper tablecloths and napkins need to absorb water immediately when food or beverages are spilled, and non-sized paper has been used because poor water absorption may cause clothes and the like to become dirty.

[0003]

It is very rare that these products are supplied as blank paper, and most of them are printed with various characters and patterns such as store names, product names, advertisements, etc. for use. However, no-size, no-coat, easily water-absorbing paper generally has low surface strength and poor printability, and is particularly susceptible to picking troubles in which the paper surface partially peels off due to ink tack or dampening water during offset printing. . In order to avoid such troubles, ordinary paper is added with a sizing agent to prevent the paper surface strength from being reduced due to absorption of dampening water, and surface paper such as polyvinyl alcohol, various starches, and styrene-acrylic resin emulsions. Although a strength enhancer is applied to increase the strength, the use of a sizing agent reduces the water absorption and the desired easily water-absorbing paper cannot be obtained. Is absorbed into the paper layer without remaining on the paper surface, which not only reduces the effect of improving the surface paper strength, but also reduces the papermaking speed due to the drying capacity of the dryer because the paper absorbs a large amount of moisture. There was a problem that had to be.

[0004] As another measure for increasing the surface strength of the non-sized paper, a method is generally used in which pulp is beaten sufficiently to strengthen the entanglement of fibers, chemical bonds such as hydrogen bonds and van der Waals bonds. I have. However, when the pulp beating degree is large, drainage of water on the wire of the paper machine becomes poor, and the paper making speed is reduced. Paper obtained by combining multiple layers of paper, such as a round-mesh paper machine, is laminated with a surface layer, a middle layer, and a back layer. Further, each layer is often combined into two to three layers. Since the ratio of the pulp to the whole is small, the papermaking speed does not decrease significantly even if the beating of the surface pulp is advanced.However, in a single-layer papermaking machine, the pulp beating degree and the Is particularly large, and there is a problem that it is not always easy to obtain a paper having good water absorbency while maintaining surface strength that can withstand severe printing conditions while maintaining the productivity of the paper machine. .

[0005]

SUMMARY OF THE INVENTION The present invention provides an easily water-absorbing paper which simultaneously satisfies the water absorption property while maintaining the productivity of a paper machine, in particular, a one-paper machine, while maintaining the surface strength suitable for printing.
And one side is easily water-absorbed, but the other side is made to obtain paper with residual size. That is,
In order to improve the paper surface strength, modified starch such as oxidized starch and cationized starch, water-soluble resin such as polyvinyl alcohol, styrene / acrylic copolymer resin, styrene / maleic anhydride copolymer resin, modified alkyd An aqueous coating agent such as an emulsion of resin is coated on one or both sides of the paper, but it is necessary to take measures to keep the coating agent on the paper surface. Generally, a sizing agent is added to the slurry of the paper stock to be made. It is done by doing. However, as described above, paper with a sizing agent added inside does not become easily water-absorbing paper, and even if no-size paper is coated with a surface strength enhancer, the coating agent penetrates into the paper layer and exerts its effect. There is a problem that can not be.

As a method that can be considered as a measure to solve this problem, there is a method in which the viscosity of the coating agent solution of the surface paper strength enhancer is increased to keep the resin on the paper surface. However, this method is not only disadvantageous in terms of cost due to the large amount of resin coating, but also hardens the paper surface by being covered with a relatively large amount of resin layer, and is not necessarily effective for printability. In the manufacture of easily absorbable paper such as coasters and paper tablecloths, pulp slurry is used to suppress the penetration of the coating agent into the paper layer in order to increase the surface picking strength of the paper required for offset printing. Then, an internal sizing agent is added thereto in a conventional manner to make paper. When this paper is coated with polyvinyl alcohol, starch, modified starch, acrylic resin emulsion, etc. by a size press, and at the same time, a surfactant having a water-wetting and water-penetrating effect is added to the coating solution to coat the paper. Due to the internally added sizing agent, excessive internal penetration of the size press coat solution is suppressed and the surface strength is increased, and the action of the wet and permeable surfactant internally added to the size press coat agent causes the size of the sizing agent to be reduced. The effect is reduced and it becomes easy water absorption. If the above treatment is applied to both sides of the paper, the surface strength of the front and back surfaces of the paper is large, and all layers are easily water-absorbable.If applied to one side, the surface strength is large only on one side and water absorption on one side is difficult. A water-absorbing paper is obtained.

[0007] A rosin-based sizing agent is most commonly used as an internally added sizing agent. Maleic anhydride or fumaric acid is added to rosin by heating to obtain a maleated rosin or fumarated rosin, and an alkali is added to form a solution. Reinforced rosin sizing agents and emulsion sizing agents dispersed in water using an emulsifier. The rosin sizing agent is used in combination with aluminum sulfate as a fixing agent for pulp and a hydrophobizing agent. The synthetic sizing agent is a neutral sizing agent obtained by converting the C ₃ and C ₄ fractions obtained by thermally decomposing the raw material naphtha into oligomers of 3 to 4 mers and then reacting with maleic anhydride to carry out alkali saponification. It can be classified into alkylten dimer, alkenyl succinic anhydride and the like, and any of them can be used in the present invention.

Surfactants which are used in combination with a paper strength enhancer in paper containing an internal sizing agent to make them easily water-absorbing must have wettability and permeability to water, and include polyoxyethylene nonyl ether, Anions such as polyoxyethylene lauryl ether, sodium alkylnaphthalene sulfonate, fatty acid polyethylene glycol ester, lauryl polyoxyethylene soda sulfate, and polyethylene glycol oxynonylphenyl ether;
Various surfactants such as cations and amphoteric surfactants can be used in the present invention.

As described above, the water permeation preventing ability developed by the sizing agent internally added to the pulp slurry is added to the surface strength agent added to the surface paper strength agent coated by the size press to have a surface active agent having a wetting and penetrating effect. In order to reduce the amount by the agent, it is necessary to finely balance the type, combination and addition amount of the sizing agent and the surfactant to be used, and if this balance is broken, the surface effect is maintained but the size effect remains, or conversely Although it is easily water-absorbable, troubles such as a lack of surface strength occur. In addition, even if a coating solution containing a surfactant is applied to only one side of the paper with the intention of absorbing water on one side and water repelling on one side, the entire size of the internal sizing agent to be used, The selection of the combination, type and amount of surfactant in the press coat liquid is particularly important,
Careful decisions need to be made in lab tests each time.

[0010]

According to the present invention, a paper made by adding an internal sizing agent to a pulp slurry is used in a size press to apply a wettable and permeable surfactant together with a surface strength agent to both or one side of the paper. Coating has the effect of erasing the sizing properties of the internal sizing agent, and obtaining a paper that has a surface strength and all layers or one side of the paper are easily water-absorbing.

[0011]

EXAMPLES The present invention will be described with reference to examples. Parts and% used here are parts by weight and% by weight. Example 1 30 parts of NBKP and 70 parts of LBKP are beaten with a refiner to 500 ml with a Canadian free nest tester, reinforced rosin size 0.2 part, aluminum sulfate 8 3 parts of a 3% solution, prepared with a fourdrinier paper machine to a weight of 350 g / m ^2, and 2% polyvinyl alcohol with a saponification degree of 98% and a 0.3% polyalkylene oxide adduct solution by a size press. Was applied to both sides of the paper.
The size of the blank before the size press is 120
Seconds, the wax pick is 6A, the Steckigt size after application of the size press solution is 0 second, and the wax pick is 10 seconds.
A, and a paper having high surface paper strength and easy water absorption could be obtained.

Example 2 A paper was made with the same stock as in Example 1, and a size press coating solution having the same composition as in Example 1 was used except that the amount of the reinforced rosin added was increased to 0.3 part. It was applied on only one side to obtain a paperboard with a weighing of 600 g / m ² . Although the size-press coated surface of this paper was easily water-absorbing, it did not readily absorb water on the back surface, and single-sided and single-sided hardly water-absorbing paperboard was obtained. The wax pick on the application surface was 10 A, as in Example 1.

Reference Example Three-color printing was performed on the press-coated surfaces of the papers of Examples 1 and 2 using an offset printing machine, and punched into a circle having a diameter of 10 cm to examine the suitability of the coaster. The size-pressed surface had no picking trouble on the paper surface due to ink tack or dampening solution during printing, and the water absorption from the treated surface was good.

[0014]

EFFECTS OF THE INVENTION Coasters requiring high water absorption,
Although tablecloths, napkins, etc. often print shop names, product names, various patterns, letters, etc., even if no-size paper is coated with a surface strength enhancer, the coating agent is absorbed inside the paper layer. In addition to the fact that the paper strength enhancing effect is reduced and picking troubles are likely to occur due to offset ink or dampening solution during printing, papermaking speed is reduced due to the drying ability of the dryer when a large amount of water is absorbed. According to the above, while maintaining the productivity of the paper machine, by applying a liquid containing a surface strength agent and a wettability to water, a surfactant having permeability, on both sides of the sizing agent-containing paper, The agent stays on the paper surface to obtain an easily water-absorbing paper having surface strength. In addition, when the paper is applied to one side of the paper, a paper that absorbs water on one side and hardly absorbs water on the reverse side is obtained.

Claims (1)

(57) [Claims] 1. In the production of an easily water-absorbing paper having a surface strength excellent in printability, a sizing agent is added to a pulp slurry and both sides or one side of paper made by a conventional method are treated with a surface paper strength enhancer for water. A method for producing an easily water-absorbing paper, comprising coating a liquid containing a surfactant having excellent permeability and wettability, and then drying.