JPH11117187A - Drying board and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a drying board strong, hard and excellent in shock resistance by blending a paper-making fiber, zeolite powder, and heat-meltable adhesive substance for a paper-making slurry and internally adding an adhesive to the slurry or impregnating the resultant paper with the adhesive. SOLUTION: This board is obtained by the steps: adding a fixer such as a polyacrylamide-based polymer coagulant to a slurry mixture comprising 13 to 40 pts.wt. of paper-making fiber such as wood pulp, 50 to 85 pts.wt. of zeolite powder with a mean particle diameter of 0.5 to 20 μm and mean pore diameter of 2 to 20 Å, and 2 to 10 pts.wt. of heat-meltable adhesive substance such as a heat-adhesive fiber with a lower melting point; subjecting it to a paper-making process and next dehydration process so as to form substrate paper; and wetly impregnating the substrate paper with 3 to 20 wt.% of adhesives based on the weight of the substrate paper, or by the alternative steps: internally adding 3 to 20 wt.% of the adhesives to the slurry mixture based on the resultant substrate paper; and subjecting it to a fixing treatment and paper-making process. A moisture-permeable material is applied onto at least one side of the resultant drying board or the board is subjected to a cutting or punching process and enveloped in a moisture-permeable material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drying board having a moisture absorbing property and a method for producing the same. More specifically, the present invention relates to a plate-shaped drying board which is filled in a hermetically sealed package such as a pharmaceutical product, a food, a microfilm or the like, and is durable, hard and excellent in impact resistance as a support, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, silica gel, silica-alumina gel, calcium chloride, calcium oxide, anhydrous calcium sulfate, activated alumina, zeolite, and the like have been used as desiccants in hermetically sealed packaging of foods and the like that have been kept out of contact with the outside air. Paper, cloth,
What is included in a bag of nonwoven fabric, moisture permeable resin film, etc.
It has been enclosed and used together with the package.

[0003] However, when used for packaging pharmaceutical tablets and the like, there is no filling space due to the packaging form, and it is desired to increase the bending strength of the package. There has been a demand for an excellent drying material. It is a well-known fact that calcium chloride and the like, which are widely used, have problems such as generation of chlorine and deliquescent, which impair the quality of the packaged object.

In order to solve these problems, it has been disclosed in Japanese Patent Application Laid-Open No. 50-4049 that it is possible to produce a plate-like or column-shaped molded product using a clay mineral as a binder in zeolite powder.
4, JP-A-55-104913, JP-A-61-15
No. 5216 and JP-A-2-290220. Further, although not limited to the form, an extrusion molding method of a material containing rehydratable alumina and zeolite is disclosed in
JP-A-162342 and JP-A-6-39235 propose a drying material in which a molded body obtained by compression-molding zeolite and rehydratable alumina is covered with a moisture-permeable sheet. According to the proposal, the thickness is 0.5 to 15 mm
It is very difficult to obtain a thin plate having an excellent impact resistance.

On the other hand, JP-A-54-101910 discloses that
A method for producing a paper-like desiccant obtained by mixing pulp with silica gel powder having an average particle diameter of 3 to 30 μm is disclosed. Further, Japanese Patent Application Laid-Open No. 7-109673 discloses that an artificial zeolite is used in an amount of 30 to 30 μm for fibers. Although a functional fiber material mixed or adhered at 80% by weight has been proposed, it cannot be said that the support intended by the present invention is a durable, hard and excellent impact-resistant drying material.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above-mentioned disadvantages. In other words, a sheet-shaped drying material is not obtained by the extrusion molding method or the compression molding method described above, but a zeolite powder high-content paper is manufactured by a papermaking method, which is harmless in hygiene, has excellent moisture absorption performance, and is durable as a support. An object of the present invention is to provide a drying board that is hard and does not break easily and proposes a method for manufacturing the same.

[0007]

Means for Solving the Problems As a result of earnest studies, the present inventors have established a drying board and a method for producing the same, which have solved these disadvantages.

That is, papermaking fibers are mixed with zeolite powder and a heat-fusible substance to make a paper, and if necessary, an adhesive is internally added or impregnated. By heat treatment after papermaking, the zeolite powder is thermally fused to the fiber surface, entangled part or between the fibers, and in addition, the adhesive strength is increased to reduce the occurrence of powder drop by increasing the paper interlayer strength, and cutting and punching The suitability was improved.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The papermaking fibers used in the present invention include softwood unbleached kraft pulp (NUKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), and hardwood bleached kraft pulp (LBK).
P), softwood bleached sulphite pulp (NBSP), thermomechanical pulp (TMP) or other wood pulp alone or as a mixture, and non-wood pulp such as hemp, bamboo, straw, kenaf pulp or cationized pulp; Modified pulp such as mercerized pulp, microfibrillated pulp,
Synthetic fibers such as rayon, vinylon, nylon, acrylic and polyester, and inorganic fibers such as glass fiber and rock wool may be used alone or in combination as needed. The increase or decrease of the papermaking fiber depends on the amount of the zeolite powder used, but is 13 to 40 parts by weight.
It is preferable to use 12 parts by weight instead of crimped synthetic fibers because a low-density base paper can be obtained.

The zeolite powder used in the present invention means natural clinoptilolite, natural mordenite, A-type zeolite, X-type zeolite, Y-type zeolite, Pc-type zeolite, etc. as long as they have excellent moisture absorption performance. Even if it is a synthetic product, it is not particularly limited, and these powders can be used alone or in combination of several kinds. Further, in addition to zeolite, silica gel, alumina gel, silica-alumina gel, calcium oxide, activated alumina, activated clay, allophane, etc. having moisture absorption performance may be used in combination.

The size of the pores existing on the surface of the zeolite powder greatly affects the moisture absorption characteristics. The average pore diameter of the zeolite powder used in the present invention is 2 to 20 °. Powders having an average pore diameter of 20 ° or less have a relative humidity of 5 to 5.
Since it exhibits excellent hygroscopicity in the low humidity region of 40% RH, it is most suitable for pharmaceuticals, microfilms, candy, rice crackers, seasoned laver, etc. which need to be stored in the low humidity region.

The amount of the zeolite powder used is preferably 50 to 85 parts by weight. If it is less than 50 parts by weight, the amount of moisture absorption decreases,
If the amount is more than 85 parts by weight, the bending strength as a support is insufficient, and powder drop is increased, which is not preferable.

[0013] The finer the particle size, the larger the surface area is preferable.
The average particle diameter is preferably 0.5 to 20 [mu] m since the roughness of the paper increases and the amount of powder falling increases.

In the present invention, a heat-fusible substance is used in combination with the above-mentioned mixture of papermaking fiber and zeolite powder. The heat-fusible substance is a low melting point obtained by compounding polyolefin fibers such as polyethylene, synthetic pulp, and polypropylene, and microfibrillated fibers thereof, hot water-soluble fibers such as polyvinyl alcohol fibers, polypropylene, polyethylene, and polyester. In addition to heat-adhesive fibers, thermoplastic elastomers, ionomers, modified ionomers, vinyl acetate copolymerized polyolefins, low-density olefins, low-molecular-weight polyolefins, stearic acid, calcium stearate, zinc stearate, ethylene bisstearate amide, A mixture of polyolefins and wax emulsions and dispersions, such as carnauba wax, microcrystalline wax and beeswax, alone or mixed
Although it is used in an amount of 10 to 10 parts by weight, it is particularly preferable to use a material having a melting point of 140 ° C. or less, which can be heat-sealed during the drying step in papermaking.

The heat-fusible substance can fuse powder between entangled portions of fibers or between fibers, improve the strength between paper layers, and greatly reduce powder dropping. In addition, polyolefin and wax reduce the frictional resistance of the blade at the time of cutting, so that it is easy to cut and the abrasion of the blade is also improved. If the amount is less than 2 parts by weight, these effects are not exhibited. If the amount is more than 10 parts by weight, it is unfavorable because in a drying step after papermaking, it is fused to a drier and production becomes difficult.

In the present invention, the base paper may be internally added or impregnated with an adhesive as necessary. As an adhesive to be used, a synthetic rubber latex such as SBR or MBR, an acrylic emulsion, an ethylene-vinyl acetate emulsion, a copolymer emulsion thereof, casein, starch, polyvinyl alcohol, or the like is used in an appropriate combination. When the adhesive is internally added, the adhesive is added to a slurry obtained by mixing the above-described base paper material, and the adhesive is fixed on the fibers together with the zeolite powder using a fixing agent.

As the fixing agent, one or more polymer flocculants such as polyacrylamides, aluminum salts such as aluminum sulfate, and known fixing agents for papermaking such as polyethyleneimine can be appropriately used.

When the adhesive is impregnated, either a wet impregnation method or a dry impregnation method is used. The wet impregnation method is a method in which a mixed material of a base paper is once made, a wet paper web is placed on a wire, moisture is squeezed out, and simultaneously an impregnation liquid is impregnated inside the paper. In the dry impregnation method, after drying the base paper,
This is a method of impregnating with an off-machine impregnating machine. In order to obtain a drying board having good air permeability and moisture permeability, a wet impregnation method is desirable. The amount of the adhesive used is preferably 3 to 20% based on the weight of the base paper. If it is less than 3%, the board has poor flexibility, and if it is more than 20%, the amount of moisture absorbed is undesirably reduced.

In the present invention, usually, an adhesive and a fixing agent are internally added to a slurry in which a zeolite powder and a heat-fusible substance are mixed with papermaking fibers, and a known conventional fourdrinier or circular net papermaking machine is used. The paper is machined to obtain a drying board having a thickness of 0.5 to 4.5 mm. In order to further increase the moisture absorption, several sheets may be bonded to each other with an adhesive to obtain a desired thickness.

The drying board thus obtained is:
After laminating one or both sides with a moisture-permeable material, it can be cut or punched into a desired size or shape. In addition, when one side extremely dislikes powder dropping from the cross section, the drying board is cut or punched into a desired size and shape, and then packaged and included in a moisture-permeable material. The processed product subjected to these treatments is usually 130 to 1
After heat treatment at 70 ° C. for about 2 hours, it is stored in a moisture-proof closed container until immediately before use.

The moisture-permeable material used in the present invention is paper,
Any material having excellent moisture permeability and air permeability, such as cloth, nonwoven fabric, and resin film, can be used. Further, a material having heat sealability, a resin film such as polyethylene or polypropylene having perforated holes, and a shrink wrapped film made of a shrinkable PVC film having good air permeability can be used. Whether to coat or include the moisture-permeable material is determined appropriately according to the amount of powder that should be allowed in the use situation. In addition, the moisture-permeable material may be enclosed in a bag or a tray using a single packaging material or a composite packaging material of a moisture-permeable material and a moisture-impermeable material, and it is necessary to select a moisture-permeable material that does not impair moisture absorption.

[0022]

EXAMPLE 1 Softwood Kraft Pulp (NBKP) 25 parts by weight, heat-fusible substance (trade name "TJ04CN", manufactured by Teijin Limited) 5
Parts by weight and 70 parts by weight of zeolite (trade name: "Silton B", manufactured by Mizusawa Chemical Industry Co., Ltd.), and a uniform slurry obtained by defibration has a sulfuric acid band of 5% based on the solid content.
After adding and stirring, a polymer anionic coagulant (trade name “Hi Holder 351”, manufactured by Kurita Kogyo Co., Ltd.) was added to 0.1%.
002%, and the basis weight of 1000
g / m ² of drying board was obtained.

Example 2 25 parts by weight of softwood kraft pulp (NBKP), 5 parts by weight of a heat-fusible substance ("TJ04CN") and 70 parts by weight of zeolite ("Silton B") were mixed and defibrated. The homogeneous slurry was internally mixed with 15% of adhesive (trade name "Polylac 750", manufactured by Mitsui Toatsu Chemicals, Inc.) based on the weight of the base paper. After stirring, 0.002% of a polymer anionic coagulant (“High Holder 351”) was further added,
A drying board having a basis weight of 1150 g / m ² was obtained using a fourdrinier paper machine in a conventional manner.

EXAMPLE 3 15 parts by weight of softwood kraft pulp (NBKP), 10 parts by weight of a heat-fusible substance ("TJ04CN") and 75 parts by weight of zeolite ("Silton B") were mixed and defibrated. In a uniform slurry, add 7 sulfuric acid bands to the solids.
% Was added, the web further polymeric anionic flocculant after stirring was added ( "high Holder 351") 0.002%, a basis weight of 1000 g / m ² (oven-dry basis) in Fourdrinier conventional manner Was paper-formed, wet-impregnated with an adhesive (“Polylac 750”) by 15% based on the weight of the base paper, and then heated and dried to obtain a drying board of 1150 g / m ² .

Example 4 On both sides of the drying board obtained in Example 1, a basis weight of 30 g was applied.
/ M ^2, a heat-fusible nonwoven fabric (trade name “Elves”, manufactured by Unitika Ltd.) is hot-press bonded and has a basis weight of 1060 g / m ^2.
Was obtained.

Example 5 The drying board obtained in Example 1 was vertically guillotineed by 3c.
After cutting the m × horizontal 6 cm, it was sealed in a bag of moisture permeability material having a basis weight of 50 g / m ² ( "ELEVES").

Comparative Example 1 55 parts by weight of softwood kraft pulp (NBKP), 5 parts by weight of a heat-fusible substance ("TJ04CN") and 40 parts by weight of zeolite ("Silton B") were mixed and defibrated. In a uniform slurry, add 5 sulfuric acid bands to the solids.
%, And after stirring, 0.002% of a high-molecular anionic coagulant (“Hi Holder 351”) was further added, and a drying machine having a basis weight of 1000 g / m ² was obtained using a Fourdrinier paper machine in a conventional manner.

COMPARATIVE EXAMPLE 2 12 parts by weight of softwood kraft pulp (NBKP), 1 part by weight of a heat-fusible substance ("TJ04CN") and 87 parts by weight of zeolite ("Silton B") were mixed and defibrated. Internally add and mix so that the uniform slurry contains 2% of adhesive (“Polylac 750”) based on the weight of the base paper,
7% of a sulfuric acid band was added to the solid content, and after stirring, 0.002% of a polymer anionic coagulant (“Hi Holder 351”) was further added.
A drying board of 00 g / m ² was obtained.

Comparative Example 3 15 parts by weight of softwood kraft pulp (NBKP), 15 parts by weight of a heat-fusible substance ("TJ04CN") and 70 parts by weight of zeolite ("Silton B") were mixed and defibrated. The homogeneous slurry is internally mixed so that the adhesive (“Polylac 750”) is contained in an amount of 25% based on the weight of the base paper, and a sulfuric acid band is added in an amount of 8% based on the solid content. Flocculant ("High Holder 351")
0.002%, and the basis weight of 1
A 150 g / m ² drying board was obtained.

Table 1 shows the evaluation results of each paper obtained in the above Examples and Comparative Examples. In addition, the evaluation result was performed about the following items. (1) Dropping of powder at the time of cutting Ten dried boards were piled up, and the end face after cutting with a guillotine was rubbed with a finger, and evaluated by four levels based on the amount of powder attached to the finger. 3 or more is appropriate. 4: Almost no adhesion. 3: There is some adhesion, but not so much as to fall off. 2: It comes off with adhesion. 1: It becomes pure white and falls off.

(2) State of end face at the time of cutting Ten dried boards were piled up, the state of the cut face after cutting with a guillotine was observed, and four-stage evaluation was performed. 3 or more is appropriate. 4: Sharp and clean cut surface 3: Does not reach sharpness, but there is no crushing etc. 2: Some crushing or crushing is observed 1: Crushing or crushing is observed

(3) Cellophane tape peeling (falling state from the surface ) Cellophane tape having a size of 18 mm x 30 mm is adhered to the surface of each dry board, and is peeled after pressing with a constant load, and the amount of powder transferred to the cellophane tape is measured. Observation and a five-step evaluation were performed. 3
The above is appropriate. 5: No transfer to cellotape at all 4: Transfer to cellotape within 3 pieces 3: Transfer to cellotape within 3 to 10 2: Transfer to cellotape within 10 to 20 1: Transfer to cellotape 1: Transfer to cellotape Countless arose

(4) Moisture Absorption Performance Each paper was heat-treated at 130 ° C. for 2 hours (weight W1 after treatment).
g), the amount of moisture absorption (%) when seasoning (weight W2 g) for 4 hours in an environment of 40 ° C. and 40% RH was measured, and a 4-step evaluation was performed. 3 or more is appropriate. In addition, it is calculated by the amount of moisture absorption (%) = (W2−W1) / W2 × 100. 4: Moisture absorption 15% or more 3: Moisture absorption 12% to less than 15% 2: Moisture absorption 10% to less than 12% 1: Moisture absorption less than 10%

[0034]

[Table 1]

Table 1 shows the following. (1) From Examples 1 to 4, by using a heat-fusible substance and an adhesive and adjusting the content, powder loss is prevented without extremely reducing the amount of absorbed moisture, and a sharp cut surface is obtained. Can be This is also evident from Comparative Example 3, which has a large amount of adhesive.

(2) In Example 4, by bonding the heat-fusible nonwoven fabric to the surface, the falling off of the powder from the surface can be greatly improved without reducing the moisture absorption.

(4) Even if the package is made of a moisture-permeable material in the fifth embodiment, the amount of absorbed moisture is not significantly affected, and powder fall can be prevented at the same time.

[0038]

As described above, according to the drying board of the present invention, the following remarkable effects are exhibited.

(1) Powder cutting can be reduced as much as possible at the time of cutting or punching and its use.

(2) A sharp cut surface can be obtained and the wear of the blade can be reduced as much as possible at the time of cutting or punching and its use.

(3) By the papermaking method, a drying board of any size, shape and thickness with excellent moisture absorption can be easily manufactured, and a strong support having impact resistance is provided by the presence of the papermaking fibers. it can.

Taking advantage of the above characteristics, the drying board obtained in the present invention can be used as a desiccant for foods such as rice crackers, cookies, candy and laver, pharmaceuticals, and electronic parts.

Claims (7)

[Claims] 1. A drying board comprising 13 to 40 parts by weight of papermaking fiber, 50 to 85 parts by weight of zeolite powder and 2 to 10 parts by weight of a heat-fusible substance. 2. A base paper comprising 13 to 40 parts by weight of papermaking fiber, 50 to 85 parts by weight of a zeolite powder and 2 to 10 parts by weight of a heat-fusible substance, and an adhesive is added to the base paper at 3 to 40 parts by weight. 20%
A drying board, characterized in that it is included. 3. The zeolite powder has an average particle size of 0.5 to 0.5.
The drying board according to claim 1, wherein the drying board has a diameter of 20 μm and an average pore diameter of 2 to 20 °. 4. A drying board according to claim 1, wherein a moisture-permeable material is bonded to at least one surface of the drying board. 5. A drying board obtained by cutting or punching the drying board according to claim 1 into an arbitrary shape and enclosing the drying board in a moisture-permeable material. 6. A mixed slurry comprising 13 to 40 parts by weight of fiber for papermaking, 50 to 85 parts by weight of zeolite powder and 2 to 10 parts by weight of a heat-fusible substance, is coated with an adhesive at a ratio of 3 to the weight of the base paper.
What is claimed is: 1. A method for producing a drying board, comprising internally adding 〜20%, fixing and drying the paper. 7. A fixing agent is added to a mixed slurry composed of 13 to 40 parts by weight of papermaking fiber, 50 to 85 parts by weight of zeolite powder and 2 to 10 parts by weight of a heat-fusible substance, and adheres to a paper web dewatered. A method for producing a board for drying, characterized in that the agent is wet-impregnated with 3 to 20% of the weight of the base paper and then dried.