JPH0280670A - Moisture permeability controlling sheet - Google Patents

Abstract

PURPOSE:To obtain a sheet capable of controlling moisture permeability by filling interstices between fibers of a nonwoven fabric sheet having mutually bound constituent fibers in a fiber web containing half or more of ultrafine fibers with a specific binder and adhering the binder thereto. CONSTITUTION:Interstices between fibers in a mixed web of >=50wt.% finedenier chemical fibers, consisting of a polyester, polyamide, etc., and having <=15mu fiber diameter and heat-fusible fibers is heated to provide a no-binder nonwoven fabric sheet having mutually bound constituent fibers at >=0.8g/cm<3> fiber density without containing a binder are filled with a blend containing a fiber binder consisting essentially of 5-50% expandable resin or resin binder, further a catalyst having oxidative decomposing and treating function and an antimicrobial agent (e.g. antifungal agent), etc., and the binder is adhered to provide a moisture permeability control sheet regulated to 1000-3000g/m<2>.24hr moisture permeability. The resultant sheet is suitable as a moisture-permeable filter in a vegetable cabinet of a household refrigerator and capable of retaining freshness of vegetables for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sheet for controlling humidity in a vegetable compartment installed in a household electric refrigerator.

[Problems to be solved by conventional techniques and inventions] Conventionally,
The vegetable compartment of household electric refrigerators was kept tightly closed to keep vegetables fresh for a long time. However, this hermetically sealed cold storage method has the disadvantage that the moisture emanating from the fresh vegetables makes the room more humid than necessary, and excess water droplets forming on the walls of the container can easily damage the vegetables.

In recent years, the humidity in vegetable compartments and rooms has been kept at a moderate level of around 90%, and only excess water is allowed to escape through a moisture-permeable filter, thereby preventing excessive evaporation of water and preventing the formation of water droplets, which can damage vegetables. A method has been proposed to preserve freshness for a long time without causing any problems.

Normally, this moisture-permeable filter material is a thin silicone film with a thickness of 10 to 30 microns that has a fine, separate pore structure and moisture permeability. Due to its structure, it has weak strength and poor handling properties, so it is essential to use a reinforcing base material.

As the above-mentioned reinforcing base material, woven fabrics and non-woven fabrics with high porosity that do not inhibit moisture permeability are mainly used, but since they are used in high humidity environments, there are problems such as mold generation and propagation. was there.

On the other hand, the effect of adsorbing and capturing ethylene gas, which is the main substance that comes out of food and reduces its freshness, has been attracting attention, and in recent years, fresh foods using various ethylene gas adsorbing substances have been developed. Although freshness-keeping materials for products have been proposed, all of them have a short lifespan because they rely on adsorption and trapping ability, and there is a problem in that no materials have been found to maintain their effects over a long period of time.

[Means to solve problems]

The present invention was made in view of the drawbacks of the moisture permeability control filter material used in conventional refrigerator vegetable compartments, and has high strength, excellent moldability and handleability, and is resistant to the growth and growth of mold, etc. This book provides a nonwoven fabric sheet with excellent moisture permeability control, which has the added function of capturing and decomposing ethylene gas, which is emitted from food and causes the deterioration of its freshness.

That is, a binder-free web containing at least 50% of fine denier chemical fibers with a fiber diameter of 15 microns or less and having a fiber density of 0.8743 or more, in which the constituent fibers of the web are thermally bonded to each other by heat-fusible fibers. 5 to 50% (D, P, U
) The foamable resin or resin binder is the main component, and the interfiber voids are filled and fixed with a binder appropriately blended with an antibacterial agent and an ethylene gas decomposition treatment catalyst, and the moisture permeability is 1000 to 5.
The problem was solved by adjusting the speed to oou/s-hah.

In the above structure of the present invention, in order to achieve uniform and stable moisture permeability, it is necessary to use a microporous base material, including fine denier chemical fibers with a fiber diameter of 15 microns or less, and polyester base materials with side lights. Contains at least 50% or more of fiber selected from , boria 2-d, polyolefin, polyacrylic, PVA, polyvinyl chloride vinyliso/, rayon, acetate, etc., either alone or in a mixture of multiple types. However, by using a binder-free high-density nonwoven fabric sheet made of these fibers and heat-adhesive fibers, moisture permeability can be stably controlled.

The fiber diameter is 15 microns or more, the fiber density is (L89/cy
If it is less than 5, the voids generated by fiber entanglement points will become larger, making it difficult to control stable moisture permeability, which is not preferable. Furthermore, if the blending ratio of the heat-melting binder am exceeds 50 percent, the area covered by the film will increase, making it difficult to obtain a homogeneous moisture-permeable filter, which is not preferable.

The moisture permeability of the binder-free high-density nonwoven fabric using fine denier fibers obtained in this way is 5000 to 1500057.
/rI! -24 hours, and it is difficult to maintain the indoor humidity at the optimum level of about 90 percent, making it unsuitable as a moisture permeable filter material for vegetable compartments, and further requiring control of moisture permeability.

That is, 5 to 50% (D,
P, U) is applied to the base material by impregnation or coating, and the microscopic voids are filled to achieve a moisture permeability of 1000 to 1000, which is useful as a moisture permeable filter material for vegetable compartments.
800017/♂・24h.

It is possible to control the desired moisture permeability by controlling the amount of ordinary non-foamed resin applied, but it is difficult to achieve uniformity and stability.

Since reproducibility is poor, a method of forming a foamable resin film is preferred.

In addition, by using antibacterial materials (antibacterial fibers, antibacterial agents) in the fiber materials, binders, etc. used, the generation and propagation of fungi can be prevented when used in high humidity environments. It can be used cleanly.

Furthermore, a catalyst effective for oxidizing and decomposing ethylene gas generated from foods is mixed into the binder.

By applying it, the removal of ethylene gas generated in the vegetable compartment is promoted, and a great effect of preserving freshness can be obtained.

A more detailed explanation will be given below based on examples.

Example 1 A mixed web of 70% fine denier polyester fibers (Q, 8dX82) with a fiber diameter of 8 microns and 5dX38mm 80% undrawn polyester fibers having heating and rowing performance was uniformly opened by a known method. A pair of calenders were used to heat the laminated fiber web to 200°C.

By calendering with a linear pressure of 1s OKp,
A nonwoven fabric sheet with a basis weight of 150 (1/rrl), thickness α17'', and fiber density α887mm5 was obtained.

The nonwoven fabric sheet obtained in this manner was impregnated with a binder of the following composition and dried with 8o9I/I! (1,).

p, U=go%) to control moisture permeability) 1
I got it.

Binder formulation 1 Water
690 copies PVA-UF170G
4 parts (polyvinyl alcohol) Unicare Resin F780 80 parts (melamine resin 1゛・5-70%) Microsphere F80 20 parts (foaming agent T・5-70%) Courtside D 20 parts (benzimidazole fungicide) Calo2ite-200200 parts (manganese dioxide rtL-f3 material ethylene gas decomposition catalyst) T.5-30% Example 2 Polyester with antibacterial properties and fiber diameter of 12 microns +e
, lta (1,5d x 51 r, qm, Kanebo ■
By calendering a uniformly spread and stacked fiber web consisting of 70% unstretched polyester R fibers gctxas+#'jlao width in the same manner as in Example 1, the fabric weight 180 ey/
lr, thickness 0.20mm, fiber band K 0.9? /c
A nonwoven fabric sheet of ss was obtained. This non-woven fabric sheet is coated with a binder of the following composition to give a dry weight of 4.
0 Moisture permeability control sheet with Q/rT11 added 8
I got it.

Binder formulation 2 Dimethylformamide 40,000 parts Rezamitsu Cu-46 2 urethane) 10 parts Calolite-2Q O 400 parts (manganese dioxide mixture-ethylene gas decomposition catalyst) TI
A uniformly opened and laminated fiber web of S-46 width X 88 = n 80% was calendered at a linear pressure of 80 K9/Country 2 using a pair of calender rolls heated to 150°C. Eye weight 150? /d, thickness 0.20m,
A non-woven fabric base material having a fiber density of 07597 was obtained.

By impregnating this non-licious fabric base material with an acrylic binder,
Dry weight Te15 (1/i (D, p, U -10%
) was obtained.

Table 1 shows the physical property values of the moisture permeability control 7-t according to Example 1.2 and Comparative Example obtained as described above.

Table 1 Comparative Example Polyester fiber with a fiber diameter of 18 microns (adXllll
fl) 70%, undrawn polyester fiber 5d-Nl:
JIS L-1099&-1 method (calcium powder method) -> 2: Abrasion resistance during 1100 cycles of washing abrasion test using a nylon bundler in a 0.5% neutral detergent solution* 8; 4: A nonwoven fabric cut into a circle with a diameter of 3α was pasted on a flat plate on which an agar medium was fixed, and a suspension consisting of three types of mixed spores was sprayed uniformly onto the surface of the medium and nonwoven fabric sample.

After culturing at 28°C for 14 days, the degree of mold growth on the sample surface was observed.

m: No mold growth was observed on the sample surface.Mold: Active mold growth was observed on the entire surface of the sample.5 each of the nonwoven fabric sheets obtained from Example 1.2 and Comparative Example
y Weigh the sample and check the ethylene gas concentration.
The mixture is placed in a 5/5 tetra pufferfish (made of fluororesin) prepared with arcvI4, and the residual rate of ethylene gas is measured after 60 minutes using a two-way gas detection tube.

(Effects of the Invention) As shown above, the moisture permeability control sheet according to the present invention is bonded with resin to form a foamed film on a high-density nonwoven fabric sheet whose interfiber voids are filled by fused fiber bonding using fine denier fibers. It is possible to stably create a moisture-permeable filter medium with excellent reproducibility by applying a resin binder that does not contain a foaming agent or a foaming agent and further uniformly packing the material to adjust the air permeability.
iB is a moisture-permeable moisture-permeable filter for refrigerator vegetable compartments that is highly strong, has excellent friction resistance and moldability, and uses antibacterial materials. It has an anti-mold effect. Furthermore, by adding a substance that has a catalytic linearization for oxidative decomposition of ethylene gas, the invention has various effects such as promoting the grouping retention effect of foods and maintaining this effect for a long period of time.

Claims (2)

[Claims] (1) Contains at least 50% by weight of chemical fibers with a fiber diameter of 15 microns or less, the constituent fibers of the web are mutually bonded by heat-fusible fibers, and the fiber density is 0.8 g/cm^3 or more. A binder-free nonwoven fabric sheet that does not contain a binder is filled with a fiber binder whose main component is 3 to 50 percent (D.P.U.) of a foamable resin or a resin binder, and the voids between the fibers are filled and fixed, resulting in a moisture permeability of 1000%. ~800
A moisture permeability control sheet that can be adjusted to 0g/m^2/24h. (2) A moisture permeability control sheet according to claim 1, characterized in that the moisture permeability control sheet contains a catalyst having a function of oxidizing and decomposing ethylene gas, and antibacterial fibers or an antibacterial agent.