JPH03118813A - Production of paperlike material made of regeneration type ion exchange fiber - Google Patents

Abstract

PURPOSE:To obtain paperlike material made of regeneration type ion exchange fiber without impairing an original ion exchange function by making the mixture of regeneration type ion exchange fiber material and a thermally adhesive fibrous binder into sheets while utilizing pure water and heat-treating the sheets. CONSTITUTION:Unregenerated cellulose-based fiber of an alkali type such as K and Na wherein a carboxylic group is introduced thereinto is regenerated by strong acid. On the other hand, unregenerated cellulosebased fiber of an inorganic salt type such as Br wherein an amino group is introduced is regenerated by strong base. These both are mixed and this mixture is made into sheets. At this time, a thermally adhesive fibrous binder constituted of composite fiber is added which has organic synthetic fiber of high m.p. as a core component and organic synthetic fiber of low m.p. as a sheath component. Then the sheets are shaped and worked into a paper shape and dried. Thereby the paperlike material in which regenerated fiber is mixed and incorporated obtained from the unregenerated type cation exchange fiber material and unregenerated type anion exchange fiber material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a recycled ion-exchange paper-like material suitable for use as a filter medium for air purification, etc., containing salts as solid or solution fine particles.

(Prior Art) It is generally known that paper-like materials made of ion-exchange fibers can be used for air purification filtration, etc. (Japanese Patent Laid-Open No. 68-24091
1, 6B-90541). However, there is no known method for industrially advantageously producing paper-like materials made of recycled ion-exchange fibers.

(Problems to be Solved by the Invention) When using paper-like ion-exchange fibers for the above-mentioned purposes, it is necessary to regenerate the cation-type ion-exchange fibers into H-type and the anion-exchange fibers into OH-type. Cation type ion exchange la pongee is usually shipped in Na type (unregenerated type) for its stability. In order to convert this into H type, it is necessary to use a strong acid such as hydrochloric acid to replace Na in the ion exchange functional group with H in the acid. Similarly, anion type ion exchange, am, is usually CI type (unregenerated type) in product packaging. In order to make this into an OH type, it is necessary to use a strong base such as caustic soda to replace 01 in the ion exchange functional group with the OH possessed by the base.

If these operations are performed after the paper is made, it is technically difficult to spread the chemicals evenly over the fibers in the paper-like material.
Regeneration cannot be performed sufficiently.

Not only that, but it is nearly impossible to completely remove the chemicals after treatment. Therefore, with this method, a paper-like material having the original ion exchange function cannot be obtained. Furthermore, when paper is made from pre-regenerated ion-exchange fiber materials using ordinary industrial water, the ion-exchange function often deteriorates during the process and the paper becomes unusable.

Furthermore, if the paper-like material of ion exchange fibers contains both unregenerated cation exchange fibers and anion exchange fibers, it is impossible to recycle the paper after papermaking. That is, in this case, when the cation exchange fiber is regenerated by acid, the exchange capacity of the anion exchange fiber is lost. Conversely, when anion exchange fibers are regenerated with a base, the exchange ability of the cation exchange fibers is lost.

An object of the present invention is to provide an industrially advantageous method for producing paper-like materials of recycled ion-exchange fibers from unrecycled ion-exchange fiber materials. The present inventors have discovered that the above-mentioned problems can be solved by regenerating unregenerated ion-exchanged vA fibers in advance.
We have discovered that this problem can be solved by paper-making the recycled fibers obtained using a specific method.

(Means for Solving the Problems) The present invention provides a method for making paper using a recycled ion exchange fiber material and a thermal adhesive fiber binder using pure water, and a method for making paper using a recycled ion exchange fiber material and a recycled anion exchange fiber material. This invention relates to a method of making paper using a heat-adhesive la pongee-like binder and pure water, and then heat-treating it.

The ion-exchange fiber material used in the present invention is a cellulose-based, polystyrene-based, vinylon-based, phenol-based, nitrile-based, etc. fiber into which a functional group imparting an ion-exchange function is introduced, and various materials are known in the art. It is.

Typical examples of the cation exchange group include a carboxylic acid group which is a weak acid group, a sulfonic acid group which is a strong acid, and a quaternary aelectronic group.

In the present invention, the unregenerated type refers to cation exchange groups such as Li, K, Na, Ca, Sr, Ba, etc.
7) 7 /l/ Refers to potash or alkaline earth metal salt type, and in anion exchange groups CI, Sr
Refers to inorganic salt types such as halogens. Moreover, the regenerated type refers to the H type in the case of a cation exchange group, and the OH type in the case of an anion exchange group. The unregenerated anion exchange fiber is regenerated by a known method using a strong acid such as hydrochloric acid or nitric acid. The regeneration treatment of unregenerated anion exchange fibers is carried out by a known method using a strong base such as caustic soda.

The recycled ion-exchange fibers obtained through the recycling process are cut as necessary during papermaking. If the fibers are too long, uneven strength tends to occur due to fiber orientation.

Also, if it is too short, it may cause dust to be generated when the paper material is removed. Therefore, the appropriate length is 8 m to 101 m.

The diameter of the ion exchange fiber used in the present invention 1ζ is usually 1 μm and 100 μm.

When producing a paper-like product made of recycled ion-exchange fibers in which cation-exchange fibers and anion-exchange fibers are mixed, unregenerated cation-exchange fibers and anion-exchange aUa are each recycled in advance, and then the two are mixed. Paper is made. In the present invention, a thermoadhesive fibrous binder is added to the recycled ion exchange fiber material used for paper making. An example of this heat-adhesive fibrous binder is a composite fiber in which a core component is organic synthetic a pongee having a relatively high melting point, and a sheath component is an organic synthetic fiber having a relatively low melting point.

Further, in the present invention, natural fibers, organic synthetic fibers, inorganic fibers, etc. that do not have ion-exchangeable functional groups are added to the recycled ion-exchange fiber material used for paper making, as necessary. For example, adding fibers with a smaller diameter than recycled ion-exchange fiber materials can improve the ability to capture microparticles in the air when the resulting paper-like material is used as a filter material for air purification. I can do it. As a material added for this purpose, glass! A pongee is preferred because it can be easily produced with a submicron diameter and has good strength, rigidity, and workability. The diameter of the fibers added for this purpose is 0.
1 to 10μ is desirable.

In the present invention, paper making is basically carried out in accordance with a wet synthetic fiber paper manufacturing method. That is, aI# material adjusted to an appropriate length is dispersed in water, and heat-adhesive Ji5Il##i is partially adhered through filtration collection, drying, and heat treatment, and a paper-like material of a predetermined thickness is formed. This is a method of manufacturing.

The pure water used in the production method of the present invention is ion exchanged,
It is manufactured by methods such as distillation and membrane separation.

The most economical method for obtaining pure water is the ion exchange method. In this case, pure water has a cation exchange resin phase,
It is obtained by effectively bringing the decarboxylation phase into contact with the anion exchange resin phase. According to the gist of the present invention, it is desirable that the pure water that comes into contact with the fibers during papermaking does not substantially contain ionic substances. However, industrially, water quality may deteriorate due to ion elution or contamination from fibers, the environment, equipment walls, etc. As a countermeasure, for example, a constant water quality can be maintained by introducing an ionic substance trapping material such as an ion exchange resin or an adsorbent into the production line.

Even so, in some cases, ionic components may be adsorbed to the regenerated ion-exchange fiber, resulting in a loss of its performance. The loss is as low as possible, for example 6%
It is desirable to keep it to a moderate level.

The ability of the filter made of the paper-like material of the present invention to clean fluids such as air is hardly impaired even if about 5% of the functional groups in the ion exchange fibers in the filter are saturated.

The quality of the pure water used in the production method of the present invention is preferably such that the upper limit permissible ion concentration of the water that actually comes into contact with the ion-exchange fibers during paper making is determined by calculation, and the water quality is such that this water quality can be maintained.

The upper limit permissible ion concentration of papermaking water can be determined as follows. Upper limit permissible ion concentration - (amount of ion exchange fibers in the dispersion liquid) x (total exchange capacity per unit amount of ion exchange fibers) x (0,05) / (amount of dispersion liquid) Dispersion liquid and fibers in the paper machine The quality of the water supply may be determined so that the ion concentration with each moderating additive added is 1ζ below the upper limit allowable ion concentration.

Specific examples of these water quality determinations will be explained by examples. The pure water used in the present invention also includes water containing ions at the above level.

In carrying out this manufacturing method, it is necessary to wash the paper machine used with pure water used for water supply. Possible cleaning methods include chemical cleaning followed by cleaning using pure water, water flushing with pure water, and the like. Additionally, the quality of pure water in use must be constantly monitored using an electrical conductivity meter, silica meter, etc. If the water quality approaches the upper limit concentration, it is necessary to take appropriate measures such as treating the dispersion again with an ion exchange device or diluting the ion concentration by adding highly purified water.

In the paper making method of the present invention, firstly, a paper having an adjusted length of m,
Add ion-exchange fibers, a heat-adhesive thin binder, and other pongee as necessary and disperse. It is necessary to thoroughly wash the regenerated fiber with the above-mentioned pure water so that no chemicals used during regeneration remain. Similarly, it is important to confirm that ionic substances are not attached to fibers other than ion exchange fibers, additives, etc. Here, if ionic substances are attached, it is necessary to perform thorough cleaning as well.

When dispersing the fibers, it is effective to use an organic dispersant or the like to obtain a paper-like material with good texture.

For example, nonionic surfactants are used.

Polyoxyethylene derivatives are currently readily available as nonionic surfactants.

The fiber material sufficiently dispersed in the dispersion liquid is collected by filtration (paper making) by a known method, shaped and processed into a paper shape, and dried. If the drying temperature rises too high, the ion exchange fibers may begin to decompose and change in quality.

For this reason, it is desirable to heat chopsticks using a method that uses precisely controlled electric heat, or a method that uses a heating medium such as steam that has a constant temperature. Desirable drying temperature is 100℃~1
The temperature is 80°C.

Although the material of the paper machine used in this manufacturing method does not matter, it is necessary that the material be sufficiently anti-corrosive. This is because metal corrosion product ions may inhibit the function of ion exchange mM. Possible countermeasures include using stainless steel, lining with resin, glass, wax, etc.

(Effects of the Present Invention) According to the present invention, a paper-like material made of recycled ion exchange fibers can be obtained without impairing the original ion exchange function.

Further, according to the present invention, both recycled *, i
A paper-like material containing a mixture of l@ can be obtained.

The regenerated ion-exchange fiber paper obtained by the method of the present invention is used for various purposes, but especially those containing both cationic and anionic regenerated ion-exchange fibers contain salts as solid or solution fine particles. It is suitable as an air purification material.

(Examples) The present invention will be specifically explained with reference to the following examples, but the present invention is not limited thereto.

Example 1 Production of Paper-like Material Containing Regenerated Both Anionic and Cationic Fibers A paper-like material made of ion-exchange fibers was produced using a round-mesh and single-mesh combination paper machine. The types and amounts of fibers used are as follows.

Regenerated anion type ion exchange am 8.54 Regenerated cation type ion exchange a fiber 8.5# Heat adhesive fibrous binder (polyvinyl alcohol type) 0.7# Glass fiber m 2.8# These fibers and some amount A dispersant (nonionic type) and a sticky agent (polymer type) were added, and 2 m of pure water Iζ was dispersed. Thereafter, paper making was performed while diluting this liquid 5 times with pure water. The paper content was approximately 180 Si/m2.

Here, since the exchange capacity of the ion exchange fiber is approximately 4 mol/# for both anions and cations, the maximum allowable ion concentration is (4 mol/#)X (8,5+8.51)X (0,
05)/(2X5L)-1,4x l Q mol/
It becomes L. The electrical conductivity of this water quality is considered to be about 10 μS/3.

For water supply, the maximum working pressure cuff 5kg f is specified in JIS B8228r Boiler Supply Water and Boiler Water Quality.
/ s2 deionized water of the same quality as the feed water of a once-through boiler was used. The electrical conductivity of this water supply is approximately 0.8μ5yc
It is x.

Drying was performed at 120° C. using a dryer using steam as a heat source. Furthermore, the electrical conductivity of the dispersion liquid is approximately 7 μS at the end of paper making.
/ts, and it was revealed that the upper limit permissible ion concentration was not exceeded.

When the total exchange capacity of the ion-exchange fiber used as a raw material and the completed paper-like material was measured by exchange of NaCl, it was found that the exchange capacity was preserved as shown below.

Anion fiber, before paper making 4.2 meq15
1 cationic fiber, before paper making 8.9 m697
9 Paper-like anion exchange capacity 4.1 meq1
51 Paper-like material cation exchange capacity 8.7 meq
/y8

Claims (2)

[Claims] (1) A method for producing a paper-like product in which a recycled ion-exchange fiber material and a heat-adhesive fibrous binder are made into paper using pure water and then heat-treated. (2) The method according to claim (1), wherein the recycled cation exchange fiber material, the recycled anion exchange fiber, and the heat-adhesive fibrous binder are made into paper using pure water and then heat treated.