JPH03180596A - Water-soluble paper giving little dissolution residue - Google Patents

Abstract

PURPOSE:To obtain the subject paper useful as a packaging paper for bathing agent, paper for divided package of fertilizer, etc., sanitary goods, etc., in high peelability and water-removability by using CMC having a specific substitution degree as a paper-making raw material, disintegrating and beating the CMC in an aqueous solution of aluminum sulfate having a specific concentration and subjecting to paper-making process. CONSTITUTION:The objective paper is produced by using CMC having a substitution degree of >=0.5 as a paper-making raw material, disintegrating and beating the CMC in an aqueous solution containing 0.3-2.5 pts.wt. of aluminum sulfate based on 1 pt.wt. of the CMC and forming a paper sheet from the dispersion.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for producing water-soluble paper with little dissolution residue.

Specifically, carboxymethylcellulose (hereinafter abbreviated as CMC-H) with a specific degree of substitution (hereinafter abbreviated as DS) is used as a papermaking raw material, and CMC-H and a specific ratio of aluminum sulfate (hereinafter A1□ (SO)) are used.

Alternatively, the present invention relates to a method for producing water-soluble paper with less dissolved residue by paper-making after beating.

(Prior art) After CMC-H is used as a papermaking raw material alone or mixed with other raw materials such as pulp to make paper, CMC-H is converted into carboxymethylcellulose alkali metal salt (hereinafter referred to as CMC-H) using an alkali metal hydroxide or an alkali metal carbonate. The method for producing water-soluble paper with alkali metal salts (abbreviated as alkali metal salts) is a well-known fact. (Special Public Interest Publication 40-908.43-12
(See 14) (Problems to be solved by the invention) - Although numerically CMC-H is considered to be water-insoluble, DS
As the temperature increases, hydrophilicity increases and swelling occurs.
It becomes sticky and water-retentive. Such properties become stronger in CMC-H which has been converted into CM to such an extent that it leaves only a small amount of dissolved residue when dissolved in water when it becomes an alkali metal salt.

On the other hand, when making paper, if the paper rope section and press section are not odor-absorbed, the strength of the wet paper paper will be weak and the transition will not be smooth. It also gets rough.

Therefore, when attempting to produce water-soluble paper by using CMC-H, which has been converted into CM to a degree that leaves a small amount of dissolved residue when dissolved in water when it becomes an alkali metal salt, using the method of the prior art described above, as a papermaking raw material, the CMC-H Due to its water retention and adhesive properties, it has poor peelability and dewatering properties in the paper rope section and press section, making it impossible to make paper. For example, when trying to make paper from CMC-H with a DS of 0.65, the wet paper does not transfer smoothly from the web to the blanket, and even if it does, as dehydration progresses, the transfer between the blankets becomes difficult, and finally will no longer migrate and papermaking will no longer be possible. In addition, CMC-H adheres to the blanket, causing serious stains and making cleaning difficult.

(Means for Solving the Problems) As a result of intensive research, the present inventors used CMC-H, which has been converted into CM to a degree that leaves little dissolved residue when dissolved in water when it becomes an alkali metal salt, as a papermaking raw material. It has been found that by disintegrating or beating CMC-H in an aqueous solution containing CMC-H and a specific ratio of A1□(SO4)i, problems with peelability and dehydration in the sieving rope section and press section can be eliminated. This led to the present invention. That is, in the present invention, CMC-H with a DS of 0.5 or more is used as a papermaking raw material, and the weight ratio with CMC-H is in the range of 0.3 to 2.5 (7) (7) A 12 (S O
-]-(7) This is a method for producing water-soluble paper with less dissolved residue by disintegrating or beating CMC-H in an aqueous solution and then paper-making. The present invention will be explained in detail below.

It is believed that when CMC-H is brought into contact with A 1 , fSO41, in an aqueous solution, CMC-H becomes CMC-Al. In fact, if you keep it in contact for a long time, CMC-
It seems that it is becoming A l. Therefore, when CMC-H is used as a papermaking raw material, Alx(SO4)= is generally not used. However, like the present invention,
As long as it is disintegrated or beaten in an aqueous solution with A1□ (S of 0.13) within a specific range, it is possible to produce water-soluble paper with little dissolution residue without any problems.

In order to carry out the present invention, it is necessary to convert CM into a CM to the extent that there is a small amount of dissolved residue when dissolved in water when it becomes an alkali metal salt.
It is necessary to use C-H as a papermaking raw material. Unless the CMC-alkali metal salt has a DS of 0.5 or more, it will dissolve in water and become cloudy and opaque instead of becoming transparent. In order to obtain a water-soluble paper with a small amount of dissolved residue, which is the object of the present invention, a DS of 0.5 or more is required.

Next A l lTS O4) a (7) Although the amount is A
l, the weight ratio of lS 041 and CMC-H is 0.3
It needs to be in the range of ~2.5. AI! (S.O.
4) If the weight ratio of s and CMC-H is less than 0.3, hydrophilicity cannot be suppressed and papermaking properties cannot be improved in any way;
When the weight ratio of H(7) is 2.5 or more, the releasability in the skid rope part and the press part becomes better, but CMC-H becomes CMC-Al and becomes water-insoluble, resulting in the desired water-solubility with less dissolved residue. Can't get paper, so A
If the weight ratio of 1 i (S 04) and CMC-H (7) is not in the range of 0.3 to 2.5, it will be uneven (Example) Examples of the present invention will be shown below. It is not limited to these in any way.

Examples 1 to 3j15 and Comparative Examples 1 to 3 2000 ml of water was put into a disintegrator, and the amount of A shown in the table was added to it.
1 lTS 04) Dissolve 3. After dissolution C, MC-
1.12 g of absolute dry amount of H (DS=0.63) was added and disintegrated. This disintegrated stock was made into paper using a sheet machine to obtain CMC- paper with a basis weight (3Q g/,!). This paper was soaked in a 5% by weight Nag COs aqueous solution, dehydrated, and dried to form water-soluble paper. The results are shown in the table.

Margins below As can be seen from the results, in Comparative Example 1, the wet paper could not be peeled off from the papermaking net, making it impossible to make paper. Further, in Comparative Example 2, although the wet paper was somehow able to be peeled off from the screen, it could not be peeled off from the filter paper after pressing, and paper making was also impossible. Furthermore, in Comparative Example 3, although it was possible to peel it off from the sieve or filter paper, the resulting paper had poor water solubility and had a large amount of dissolved residue. In contrast, Examples 1 to 3 had good releasability from the sieve and filter paper, and even when they became water-soluble papers, there was almost no dissolution residue.

(Effects of the Invention) According to the present invention, CMC-H with a DS of 0°5 or more is used as a papermaking raw material, and A 1 a (SO By disintegrating or beating CMC-H in an aqueous solution with an amount of 1, and then paper-making, the problem of CMC-H's adhesiveness and water retention improves the peelability and dewatering properties of the paper rope and press parts. It is possible to easily make paper and obtain water-soluble paper with less dissolved residue.The water-soluble paper with less dissolved residue obtained in this way can be used as packaging paper for bath additives, fertilizers, and pesticides. It can be used as wrapping paper for wrapping paper, sanitary products, and toilet cleaning products.

Claims (1)

[Claims] Paper is made by using carboxymethylcellulose with a degree of substitution of 0.5 or more as a papermaking raw material, and after carboxymethylcellulose is difficult to dissolve or beaten in an aqueous solution containing aluminum sulfate in a weight ratio of 0.3 to 2.5. A method for producing water-soluble paper with little dissolution residue.