JPH076122B2 - Water-degradable non-woven fabric - Google Patents

Description

TECHNICAL FIELD The present invention relates to a water-decomposable nonwoven fabric which has sufficient strength when used and easily hydrolyzes when immersed in a large amount of water.

[Conventional technology]

Conventional wet wipes such as baby wipes, wet tissues for women's physiology treatment or wet tissues for defecation treatment are made of long-fiber non-woven fabrics or non-woven fabrics in which fibers are bound with a water-insoluble binder to increase the wet strength of the product. Although it is used, when it is discarded in the flush toilet, the product remains in its original form, which may cause blockage in the sewer pipe.

Therefore, in order to temporarily make the binder insoluble in water in a nonwoven fabric using a water-soluble binder, JP-A-54-10496
What is impregnated with an aqueous solution containing a specific salt or a salt having a predetermined concentration necessary for salting-out as described in JP-A No. 3-2 is used.

As the above water-soluble binder, polyvinyl alcohol having a saponification degree of 85 to 99%, a boric acid aqueous solution as a specific salt solution that temporarily renders water insoluble, and a 7% sodium sulfate aqueous solution as a solution for salting out polyvinyl alcohol are used. There is.

[Problems to be solved by the invention]

Sodium sulfate aqueous solution, boric acid aqueous solution, etc. are used for the above water-soluble binders, and in terms of primary irritation to skin, cumulative irritation or allergy, irritation to ocular mucosa, oral toxicity, etc. There's a problem.

The present invention has been made to solve such a problem, and has sufficient strength in a wet state, but when immersed in a large amount of water, the strength is extremely reduced, and the nonwoven fabric is dispersed in a fibrous state. The purpose is to obtain.

[Means for solving problems]

The present invention relates to a water-decomposable non-woven fabric characterized in that a fiber product bonded with carrageenan alone or a mixture of carrageenan and galactomannan is impregnated with an aqueous salt solution.

Here, the fiber products referred to in the claims include natural fibers such as wood pulp, cotton, hemp, wool, silk or cotton linter; regenerated cellulose such as viscose rayon or cupra, modified cellulose such as cellulose acetate, nylon. Including sheet materials made of synthetic fibers such as polyamide fibers such as, vinyl chloride fibers such as Teviron (registered trademark), vinylidene chloride fibers, polypropylene fibers, acrylic fibers, polyvinyl alcohol fibers, etc. , Notebooks, notebooks, books, etc. or products such as insoles, blankets, felts.

〔Example〕

In the present invention, carrageenan or a mixture of carrageenan and galactomannan can be used as the binder, but carrageenan such as kappa carrageenan forms a random coil as shown in (a) of Fig. 1 when heated to about 70 ° C. To do.

Then, when cooled, the carrageenan molecule becomes (b) in FIG.
As shown in Fig. 3, a duffle helix is partially formed, and this is the junction zone of the gel. Upon further cooling, a regular arrangement is formed between the double helices as shown in FIG. 1 (c), and a stronger junction zone is formed.

Here, when a specific ion such as potassium ion is impregnated as the aqueous salt solution, the formed junction incorporates the specific ion into the structure of the double helix as shown in FIG. 2 and strengthens the structure. In this case, the concentration of the specific ion in the double helix and the concentration outside the molecule are in equilibrium.

Next, when the specific ion outside the molecule is removed by dialysis or the like, the specific ion inside the double helix flows out to the outside of the molecule, so that the strength of the double helix decreases and the carrageenan molecule swells and dissolves.

The present invention has been made by utilizing the properties of carrageenan as described above.

The water-decomposable nonwoven fabric of the present invention can be obtained by impregnating a fiber product bound with carrageenan alone or a mixture of carrageenan and galactomannan with an aqueous salt solution.

The non-woven fabric can be produced by any of the commonly used wet method and dry method. In the case of producing by these methods, after forming the web, it can be produced by spraying or coating carrageenan alone or a mixture of carrageenan and galactomannan, and in the case of a wet method, it is mixed with a fiber beating liquid during paper making. It can also be used.

The carrageenan makes the nonwoven fabric water-decomposable and is the main component of the binder of the nonwoven fabric, and examples thereof include copper carrageenan, lambda carrageenan, and iota carrageenan.

The galamtomannan is a component for reinforcing the structure of carrageenan and improving the strength of the nonwoven fabric, and 0 to 30 parts by weight is added to 10 parts by weight of carrageenan before use. In this case, if the amount exceeds 30 parts by weight, the properties of locust bean gum will appear, and the water decomposability of the non-woven fabric will be poor, such being undesirable.

The textile product used in the present invention is obtained by binding the non-woven fabric substrate with carrageenan alone or a mixture of carrageenan and galactomannan. In this case, when the temperature of the aqueous solution is lower than 60 ° C, the aqueous solution causes gelation, and if it exceeds 90 ° C, it is dangerous in working, so 60 to 90 ° C.
Is preferred.

The non-woven fabric substrate is, for example, natural fiber such as wood pulp, cotton, hemp, wool, silk or cotton linter, regenerated cellulose such as viscose rayon or cupra, modified cellulose such as cellulose acetate, polyamide fiber such as nylon, polyester. Synthetic fibers such as series fibers, vinyl chloride series fibers such as Teviron (registered trademark),
Examples thereof include vinylidene chloride fiber, polypropylene fiber, acrylic fiber, polyvinyl alcohol fiber and the like, and these may be used alone or in combination of two or more kinds.

Among these, natural fibers, regenerated cellulose and the like are preferable because they are easily decomposed by microorganisms such as Cellulomonas and Cell Vibrio bacteria.

Further, the fiber length is preferably about 1 to 50 mm, more preferably 5 mm, from the viewpoint of dispersibility when discarded in a flush toilet and wet strength of the product.

Further, the carrageenan alone or the mixture of carrageenan and galactomannan is preferably contained in the obtained nonwoven fabric in an amount of 5 to 10% by weight. In this case, if the carrageenan alone or the mixture of carrageenan and galactomannan is less than 5% by weight, the strength of the non-woven fabric may not be sufficiently obtained. All you need is strength. Again 10
When it exceeds the weight%, it is not preferable in terms of product cost.

When the amount of carrageenan alone or the mixture of carrageenan and galactomannan is about 10% by weight, the basis weight of the non-woven fabric is 100 to 200 g / m ² and the product has sufficient wet strength, but depending on the intended use of the product, it may be weighed. Is slightly different.

By impregnating the fiber product with an aqueous salt solution, the water-decomposable nonwoven fabric of the present invention can be obtained. The aqueous salt solution is mixed with carrageenan alone or a mixture of carrageenan and galactomannan in advance and then added to the nonwoven fabric substrate. You may use.

The salts used are, for example, potassium ions in water,
Those which generate ammonium ion, rubidium ion, cesium ion, calcium ion, barium ion and the like can be used. These ions are the components for strengthening the structure by impregnating the double helix composed of carrageenan molecules, but this concentration is taken into consideration in the obtained nonwoven fabric in consideration of the osmotic pressure of human body fluids. It is preferable to add it so as to be 290 m Osm / or less.

For example, in the case of potassium chloride, 1.08% by weight or less is preferable, and in the case of calcium chloride, 1.07% by weight or less is preferable.

Further, sodium ions or lithium ions having a small ionic radius are not preferable because they easily pass through between the double helices.

In addition to the above-mentioned salts, it reacts with sulfate groups present in carrageenan molecules to crosslink the molecules of galagenan, which has the effect of increasing gel strength, including calcium ions, divalent cations such as barium ions, and galactomannan. Locust bean gum, tara gum, or the like, which is one of the above, can be used.

The locust bean gum is one in which galactose side chains are bound to mannose and the main chain, but the distribution of the side chains is not uniform, and a portion having no galactose side chains and a portion having no side chains at all. is there. The galactose and the portion having no side chain associate with the double helix chain of carrageenan as shown in FIG. 3, and reinforce the gel structure as a whole.

This shows the effect of potassium chloride concentration used as an example of salts on the gelation and re-dissolution temperature of carrageenan. Fig. 4 ("Fragrance Journal", 1981, published by Fragrance Journal, 46th issue, p. 64) Citation) and FIG. 5 showing the relationship between the addition of locust bean gum and gel strength (“Fragrance Journal”, 1981, published by Fragrance Journal, 46th edition, p. 64).

From FIG. 4, it can be seen that as the concentration of potassium chloride decreases, the re-dissolution temperature of the gel decreases, that is, it easily dissolves, and finally gelation does not occur.

Also, from FIG. 5, by adding locust bean gum,
It is recognized that the gel strength is remarkably increased.

It has also been reported that tara gum has the same effect.

From the above, it is understood that the solubility of the gel of galagenan or a mixture of carrageenan and locust bean gum depends on potassium ion, ammonium ion and the like. Therefore, the non-woven fabric produced by binding fibers by these retains its form in an aqueous solution containing potassium ions, ammonium ions and the like, and when it is re-immersed in a large amount of water, it is dispersed in a fibrous form.

The nonwoven fabric of the present invention obtained as described above may be used by being impregnated with various aqueous solutions, or may be prepared by previously mixing various aqueous solutions with a nonwoven fabric base material.

As the above aqueous solution, for example, an aqueous solution of an activator such as sodium polyoxyethylene lauryl ether sulfate and polysorbate 20 (manufactured by ICI USA) is added to the wet tissue, try tissue, hand wipe since it has excellent water absorption. Cleaning cloth, diapers, pants,
Polyethylene glycol or polypropylene glycol may be added to sanitary napkins, tampons, etc. to have flexibility, and a drug having a therapeutic / preventive effect on skin diseases including antiseptics such as potassium methylparabensorbate. It can be used in surgical masks, surgical hats, surgical gloves, liners, etc. by adding an appropriate amount thereof.

Further, since the water-decomposable nonwoven fabric of the present invention disperses in a fibrous state when immersed in a large amount of water, plant fertilizer is added, as a sheet-like plant fertilizer, or as a soil improver by adding polyvinyl alcohol or the like. It can also be used.

In addition to these, by incinerating conventional textile products,
Although there was a problem of generating toxic gas, the water-decomposable nonwoven fabric of the present invention does not contain harmful substances, and since it does not have a problem of soil contamination, it can be embedded in soil and disposed of. It can be applied to various products.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the examples.

Example 1 Genu Visco CSW-1 (sodium salt of copper carrageenan, manufactured by Copenhagen Pectin), water temperature of 70 ° C, 0.5%
600 ml of aqueous solution and NBKP pulp (Miki Tokushu Paper Co., Ltd. 9 g
Was placed in a household mixer (SJ610 manufactured by Sanyo Electric Co., Ltd.), stirred, paper-made on a 20-mesh stainless net, and dried to give a nonwoven fabric weighing 151 g / m ² .

In order to measure the wet strength of the obtained non-woven fabric, this non-woven fabric was cut into strips with a width of 15 mm and a length of 50 mm, and these were used as test solutions in KCl, K ₂ SO ₄ , KH ₂ PO ₄ , CaCl ₂ , and NH ₄ Cl. , NaCl 1 each
% Aqueous solution and distilled water for 1 hour, the solution was lightly wiped with a tissue and the tensile strength was measured.

The tensile strength was measured by using a universal compression tensile tester (TCM-200 manufactured by Shinko Communication Industry Co., Ltd.) at a tensile speed of 50 mm / min and a test piece gripping interval of 20 mm. In addition, the load instruction value at the time of breaking the nonwoven fabric was defined as the tensile strength.

The results are shown in Table 1.

The sample obtained by immersing the non-woven fabric obtained above in a 1.0% potassium chloride aqueous solution has a water flow rate of 500 ml / min and a water temperature of 18 ° C.
Was re-immersed in water and the change in tensile strength with time was measured.

The results are shown in Table 2.

Comparative Example 1 A nonwoven fabric was prepared in the same manner as in Example 1 except that polyvinyl alcohol B-17 (manufactured by Denki Kagaku Kogyo Co., Ltd.) was used instead of Genu Visco CSW-1. The tensile strength when immersed for 1 hour was measured.

The results are shown in Table 1.

Comparative Example 2 A non-woven fabric was prepared in the same manner as in Example 1 except that sodium alginate (manufactured by Wako Pure Chemical Industries, Ltd.) was used in place of Gunu Visco CSW-1.
The tensile strength when immersed for a period of time was measured.

The results are shown in Table 1.

Moreover, the time-dependent change of the tensile strength when re-immersing in water was measured in the same manner as in Example 1.

The results are shown in Table 2.

As is clear from Table 1, Genu V as a carrageenan
It can be seen that the wet strength of the non-woven fabric prepared by using isco CSW-1 impregnated with the aqueous solution of potassium, calcium and ammonium salt is higher than that of the non-woven fabric impregnated with sodium salt or distilled water. Even with the same potassium salt,
The reason why the tensile strength in the case of monopotassium phosphate is smaller than that in the case of potassium chloride is because the molar concentration of ions is small, and it is considered that the same tensile strength can be obtained if the molar concentrations are made equal. To be

It can be seen from Table 2 that the non-woven fabric obtained in Example 1 remarkably decreases in strength when re-immersed in water, and finally disperses in a fibrous form. By the way, the condition under which the nonwoven fabric can be disposed of in the flush toilet is that the tensile strength of the nonwoven fabric is 50 g or less, so that the nonwoven fabric obtained in Example 1 can be sufficiently used.

Further, the non-woven fabric obtained in Comparative Example 2 does not undergo any decrease in strength even after being re-immersed in water for 24 hours. It is considered that this is because the carboxyl group existing in the molecule reacts with calcium ion to cause water-insoluble precipitation of calcium alginate.

Examples 2-6 Genu Visco CSW-1 and Genu G as Locust Bean Gum
um RL-20 (manufactured by Copenhagen Pectin Co., Ltd.) was blended to give a composition as shown in Table 3 in a weight ratio, and the water temperature was 70%.
After preparing a 0.5% aqueous solution at 0 ° C., a nonwoven fabric was prepared in the same manner as in Example 1.

The obtained non-woven fabric is 15 mm wide and 50 mm long in the same manner as in Example 1.
Was cut into strips and dipped in an aqueous potassium chloride solution for 1 hour, and the tensile strength was measured.

The results are shown in Table 3.

Next, the tensile strength of a non-woven fabric prepared by mixing Genu Visco CSW-1 and Genu Gum RL-200 at a mixing ratio (weight ratio) of 1: 1 was re-immersed in 0.1% KCl aqueous solution. The change was measured.

The results are shown in Table 4.

It can be seen from Table 3 that the addition of RL-200 increases the wet strength of the nonwoven fabric. The addition of RL-200 is preferable in terms of strength and cost of raw materials when the weight ratio with carrageenan is 1: 1. If the ratio of RL-200 to carrageenan exceeds 300% by weight, the water solubility of the nonwoven fabric is increased. It is not preferable because it makes it difficult to see

In addition, it can be seen from Table 4 that when RL-200 is added, the hydrolysis rate is somewhat faster, and it is sufficiently dispersed in a fibrous state in 1 hour.

Example 7 Genu Gel SWG (calcium salt of copper carrageenan,
A nonwoven fabric was manufactured from Copenhagen Pectin Co., Ltd.) in the same manner as in Example 1 and impregnated with an aqueous potassium chloride solution in the same manner as in Examples 2 to 6 to measure its tensile strength.

The results are shown in Table 5.

Example 8 A nonwoven fabric was produced in the same manner as in Example 1 with Genu Gel SWG and Genu Gum RL-200 at a mixing ratio (weight ratio) of 1: 1.

The tensile strength of the obtained nonwoven fabric was measured in the same manner as in Example 2 by impregnating it with an aqueous potassium chloride solution.

The results are shown in Table 5.

A sample obtained by impregnating the obtained non-woven fabric with a 0.5% aqueous solution of potassium chloride was re-immersed in water in the same manner as in Example 1, and the change in tensile strength with time was measured.

The results are shown in Table 6.

From Table 5, it can be seen that even a 0.01% aqueous solution of potassium chloride has wet strength.

In addition, it can be seen from Table 6 that when the calcium salt of copper carrageenan is used, the wet strength of the product is higher than that when the sodium salt is used, and the water degradability is not lowered.

Example 9 Wetting of a nonwoven fabric obtained by mixing a mixture of Genu Gel SWG and Genu Gum RL-200 in a weight ratio of 1: 1 in the same manner as in Example 1 and impregnating with ammonium chloride. The changes with time of the tensile strength and the tensile strength when re-immersed in flowing water were measured by the same method as in Example 1.

The results are shown in Tables 7 and 8, respectively.

Example 10 The wet tensile strength and the change with time of the tensile strength when re-immersed in flowing water were measured in the same manner as in Example 9 except that calcium chloride was used instead of ammonium chloride.

The results are shown in Table 9 and Table 10, respectively.

As can be seen from Tables 7 to 10, similar results can be obtained by using ammonium salt or calcium salt instead of potassium salt. The reason why the water decomposability is lower when calcium salts are used than when ammonium salts are used is considered to be because calcium ions are cross-linked with carrageenan molecules.

Example 11 The non-woven fabric obtained in Example 8 was cut into a 10 cm × 10 cm square and impregnated with an aqueous solution having the composition shown in Table 11 to prepare a wet tissue.

The flowability test of this wet tissue was performed by using the flush toilet equipment shown in FIG. 6 under the following measuring method and measuring conditions.

(Measurement method) Toilet bowl (JIS A 5207; C 316) (3) and the toilet bowl (3) 500m
m The low tank (1) provided above is connected with a polyvinyl chloride pipe (2) with an inner diameter of 32 mm provided with a cock (7) at the upper end, and below the toilet bowl (3) is a transparent polychlorinated product with an inner diameter of 75 mm. A vinyl pipe (4) and a transparent vinyl chloride pipe (5) with an inner diameter of 100 mm and a gradient of 1/100 are connected to the septic tank (6).

Next, sample (5 wet tissues) in the toilet bowl (3)
Then, tap water 10 in the low tank (1) is flown through the cock (7), and the flowability of the sample is observed in the pipes (4) and (5). In addition, the sample flowing at the inlet of the septic tank (6) is received in a container, and occasionally stirred lightly to examine the water decomposability in the septic tank (6).

(Measurement conditions) Flow rate: 10 / time Number of tests: 5 / time Number of tests: 50 times The results are shown in Table 12.

As can be seen from Table 12, the obtained non-woven fabric does not block the sewage pipe and is dispersed in a fibrous state in the septic tank, and it can be seen that it can be sufficiently used practically.

[Effects of the Invention] As described above, the water-decomposable nonwoven fabric of the present invention is easily hydrolyzed when immersed in a large amount of water, and since it is safe for the human body, it can be used for wet tissue, dry tissue, hand-wiping, and cleaning. By adding a sterilizing and disinfecting agent to pants, diapers and the like used in hospitals, etc., such as clothes, it can be applied to various products such as surgery, food gloves and hats.

[Brief description of drawings]

FIG. 1 is a schematic view showing the mechanism of gelation of carrageenan,
Fig. 2 is a state diagram of potassium ions incorporated in the double helix of carrageenan, Fig. 3 is a state diagram of carrageenan when locust bean gum is added, and Fig. 4 is the concentration of potassium chloride and gelation of carrageenan. Relationship between temperature and melting point, Fig. 5 shows synergistic effect of copper carrageenan and locust bean gum, and Fig. 6
The figure shows the flush toilet equipment diagram of the flowability test of the wet tissue used in Example 11.

Claims (1)

[Claims] 1. A water-decomposable non-woven fabric characterized in that a fiber product bonded with carrageenan alone or a mixture of carrageenan and galactomannan is impregnated with an aqueous salt solution.