JPH03217A - Moisture absorbable and desorbable sheet and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain sheet, which has excellent moisture absorption and desorption characteristics, the hand feeling of which are warm, the surface of which is smooth and which is excellent in antifouling properties, by a method wherein moisture permeable synthetic resin such as moisture permeable polyurethane resin or the like is mixed with wood powder and, after that, shaped into a form of sheet. CONSTITUTION:Moisture permeable resin 1, which is solvent-soluble, hard to be swollen by water and has film-forming properties, such as moisture permeable polyurethane resin is used normally under the state being dissolved in organic solvent or may be used in the form of emulsion. Compound is prepared by uniformly mixing said solution with wood powder 3 and other proper additive, when necessary. The compound is continuously applied by a certain thickness on base material such as releasing paper or the like and, after that, heated up to the predetermined temperature in order to be dried. Next, after cooling, sheet is peeled off the base material and taken up in the form of roll.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a moisture absorbing and releasing sheet that can be used in various fields as an interior material and a surface material for equipment to prevent dew condensation, and a method for manufacturing the same.

[Conventional technology]

Wood-like interior materials, OA equipment, optical equipment, home appliances, kitchenware, furniture, office equipment, stationery, office supplies, crafts,
BACKGROUND ART Sheets and decorative boards made of soft or hard synthetic resins such as vinyl chloride resin, acrylic resin, phenol resin, and melamine resin are often used as surface materials for stairs, floors, etc., or as decorative materials. Furthermore, as natural materials, decorative boards made of thin plates of wood, cork, etc. or powder thereof formed into a plate shape, decorative sheets made of paper, cloth, etc. are used.

In addition, by adding a polymeric hygroscopic agent made of a super absorbent resin into a vinyl chloride resin and forming it into a sheet, and dispersing and embedding the fine powder of the polymeric hygroscopic agent in the sheet-like vinyl chloride resin layer, Attempts have also been made to impart hygroscopic properties to vinyl chloride resin sheets.

[Problem that the invention seeks to solve]

Among the above-mentioned conventional surface materials and decorative materials, synthetic resin decorative boards and decorative sheets have surfaces that are hard to stain and are easy to wipe off even if they become dirty, but because they do not have moisture absorption and release properties, they are prone to condensation and stuffiness. Depending on the use, the surface gloss, texture, etc. may not be completely satisfactory. In addition, soft synthetic resin sheets containing plasticizers, such as soft vinyl chloride resin sheets,
During use, the plasticizer is liberated and the sheet hardens and deteriorates.

Decorative sheets made of paper or cloth have moisture absorbing and desorbing properties, but they are easily stained and it is difficult to wipe off the adhered stains. Boards and sheets made of wood or cork have a nice texture and excellent moisture absorption and desorption properties, but they stain easily, are difficult to wipe away, and are expensive.

Furthermore, in the case of vinyl chloride resin sheets in which a polymeric moisture absorbent is dispersed and embedded, the moisture absorbent exposed on the sheet surface absorbs moisture well;
Since the moisture absorbent buried inside the resin layer is covered with non-moisture permeable vinyl chloride resin, its moisture absorption ability is significantly inhibited, and for the same reason, the moisture absorbed by this agent is difficult to dissipate. , sufficient moisture absorption and desorption properties cannot be expected.

Therefore, the present invention has excellent moisture absorption and desorption properties and antifouling properties, and prevents dew condensation.
To provide a moisture-absorbing and releasing sheet that has an effect of preventing stuffiness and has an excellent texture, and a method for producing the same.

[Means for solving problems]

In order to achieve the above object, the present inventors have conducted extensive research and found that by mixing wood flour with a moisture-permeable synthetic resin such as a moisture-permeable polyurethane resin and forming it into a sheet, it has excellent moisture absorption and release properties. It was discovered that a sheet with a warm texture and touch, a smooth surface, and excellent stain resistance could be obtained, and the present invention was completed.

That is, the gist of the present invention is a moisture-absorbing and desorbing sheet formed by embedding wood flour in a moisture-permeable resin layer.

Still another aspect of the present invention is to uniformly mix a moisture-permeable synthetic resin and wood flour, and uniformly apply the resulting compound to the surface of a base material.
The gist of the method is to provide a method for producing a moisture absorbing and desorbing sheet according to claim 1, wherein the sheet is formed into a sheet by peeling it off from the base material after heating and drying.

The moisture-permeable resin used in the present invention is not particularly limited as long as it is soluble in solvents, does not easily swell with water, and has film-forming ability, but known moisture-permeable polyurethane resins are preferably used. In addition, for example, vinyl alcohol resin, vinyl acetate resin, acrylic resin,
Amino acid resins and the like can be used. These moisture-permeable resins have a moisture permeability of 1000g/m'・2 for a film (film thickness 10μ) measured by JIS Z-0208B method.
Those having 4H or more are preferable.

The wood flour used in the present invention is not particularly limited by the type of wood, but powders from coniferous trees such as fir, toga, and cedar, which have a low oil content and are excellent in hygroscopicity and aromatic properties, are preferable. Further, cork powder etc. can also be used. These wood flours are used by pulverizing wood or the like into finer particles than 10 meshes, preferably finer than 20 meshes.

If it is coarser than 10 meshes, it will be difficult to apply it continuously during sheet forming, which will be described later.

To produce the moisture-absorbing and desorbing sheet of the present invention, the moisture-permeable resin is usually dissolved in an organic solvent, but it may be in the form of an emulsion. The solid content in these solutions or emulsions is 10 to 50% by weight, and the solution viscosity is 100 to 50%.
It is adjusted so that it becomes 00CPS. Next, the wood flour and other additives as required are appropriately added to this solution and mixed uniformly to prepare a compound.

The mixing ratio of the above-mentioned wood flour and moisture-permeable resin is preferably 10 to 500 parts by weight of wood flour per 100 parts by weight of resin solid content in the solution. If it exceeds 500 parts by weight, it is not suitable because it will not have sufficient fluidity to be coated on a base material such as release paper during sheet forming.

Moreover, if it is less than 10 parts by weight, it is inappropriate because the moisture absorption and release performance and dew condensation prevention performance of the sheet deteriorate.

When mixing this wood flour, it is important to use an appropriate method such as a dissolver, a homodisper, or a paint roll to uniformly mix and disperse the wood powder.

The compound has fluidity and the viscosity range in which it can be uniformly coated on the substrate is 50,000 CPS (2
5°C) or lower is appropriate.

Further, when powder of a polymeric moisture absorbent such as isobutylene-maleic acid copolymer or polyacrylic acid salts or an inorganic moisture absorbent such as bentonite or zeolite is added, the moisture absorption and desorption performance is further increased.

In carrying out this invention, in addition to the above-mentioned ingredients, various dyes, pigments, weathering agents, deodorizing agents, fragrances, antifungal agents, flame retardants, matting agents, and other fillers may be added as necessary. It can be added as appropriate.

It is also possible to add a thermally decomposable or microcapsule type foaming agent to the above compound to foam the coating film on the substrate after coating the substrate.

Known coating methods such as gravure coating, doctor blade coach ink, reverse roll coating, and extrusion coating can be used to mix the various compounding ingredients as described above and apply the prepared compound to a base material such as release paper. Recruit as appropriate.

In some cases, instead of using a solution or emulsion of a moisture-permeable resin, a moisture-permeable thermoplastic resin and wood flour may be used and formed into a sheet using an extruder.

The compound is continuously coated to a certain thickness on a base material such as release paper, and dried by heating to a certain temperature. The thickness of the coating after drying is 50 to 5000μ, especially 100 to 100μ.
0μ is preferred. The drying temperature is usually 40 to 200°C, and the solvent evaporates by heating at this temperature for several minutes. After cooling, the sheet is peeled off from the base material and wound into a roll.

Various methods can be used to decorate the surface of the sheet, such as embossing the coated surface after drying or printing various colors and patterns. Further, by applying an adhesive or a pressure-sensitive adhesive to the back side of the peeled sheet and pasting a release paper or the like on it, a sheet that can be easily adhered during pasting work can be obtained.

[Effect]

The sheet of the present invention is a moisture-absorbing and desorbing sheet composed of a moisture-permeable urethane resin, wood flour, filler, etc., and it quickly absorbs and desorbs moisture in response to changes in humidity, and when used as an interior material or a surface material for equipment. , is extremely effective in preventing condensation.

That is, when the moisture-absorbing and desorbing sheet of the present invention is used by pasting it on a wall or the surface of equipment, when the humidity is high, water vapor penetrates into the interior of the sheet through the moisture-permeable resin layer and temporarily absorbs the wood powder inside. occluded. When it becomes dry, the previously absorbed moisture passes through the moisture-permeable resin layer and quickly evaporates from the sheet surface, allowing moisture absorption and desorption to closely follow the changes in environmental humidity. As a result of this breathing action, condensation on the sheet surface is suppressed.

Furthermore, since it is filled with wood flour, it has heat insulating properties, further increasing its dew condensation prevention effect.

In addition, since the moisture absorbing and releasing sheet of the present invention has the surface of the wood flour covered with a moisture permeable resin, the surface is non-porous and does not get clogged even if dirt adheres to it. Since dirt can be easily wiped off, the natural texture unique to wood flour can be maintained for a long time, and moisture permeability does not decrease. Furthermore, since the sheet has hygroscopic properties, it also has an antistatic effect.

The sheet of the present invention can be used indoors in houses, stores, offices, etc.
Transportation equipment such as elevators, automobiles, railway vehicles, and ships, interior materials for equipment, OA equipment such as computers, word processors, etc.
Optical equipment such as cameras and microscopes, home appliances such as telephones, televisions, stereos, and videos, kitchen utensils such as cabinets, sinks, and cupboards, furniture such as chests, desks, chairs, and bookshelves, office equipment, albums, and book covers. It can be applied to a wide variety of fields, including stationery and office supplies such as notebooks, daily necessities such as bags, packages, and cosmetic cases, crafts, and surface materials for stairs and floors.

〔Example〕

Example 1 Moisture-permeable urethane resin (manufactured by Toyo Rubber Industries, Ltd.: NY8
14) Using the knife coater method, coat the solution to a thickness of 20 μm.
A film was created and its moisture permeability was determined according to
When measured by the 8B method, it was 4300 g/m''24H.

Next, 80 mesh of wood flour was added to this solution at a ratio of 100 parts by weight of wood flour per 100 parts by weight of solids in the solution,
A compound was prepared by uniformly mixing using a paint roll. This compound was applied uniformly onto a release paper using the knife coating method, heated and dried in a heating oven at 70°C for 2 minutes, and after cooling, the sheet was peeled off from the release paper to create a moisture-permeable compound containing wood flour. A sheet with a thickness of 260 μm consisting of a urethane resin layer was obtained.

FIG. 1 is a sectional view showing the structure of the moisture absorbing and releasing sheet of the present invention obtained by the above method. In the drawing, (1)
(2) is a moisture-permeable urethane resin, and (2) is wood flour.

When the above-mentioned sheet and a vinyl chloride resin sheet were attached to the surface of a cosmetic case, the vinyl chloride sheet had a glossy surface, lacked a soft texture, and was cold to the touch. Also, if you hold it as a listener for a long time, sweat will adhere to it.

On the other hand, the sheet to which the sheet of the present invention was attached had the feel and warmth of natural wood, and had an extremely superior texture compared to the vinyl chloride sheet.

Furthermore, since the sheet of the present invention has moisture absorption and desorption properties, it did not sweat or feel stuffy even when held in the hand for a long time.

Furthermore, since the sheet of the present invention does not have a base material, it is flexible,
In particular, when moisture-permeable urethane resin is used as the moisture-permeable resin,
It is highly flexible and stretchable, and when attached to the surface of an item,
It is easy to attach parts of corners, etc., and can be attached neatly.

Furthermore, when a book cover was made using the moisture absorbing and desorbing sheet of the present invention, a book cover that was comfortable to the touch and had a high quality texture was obtained.

[Effects of the Invention] The moisture absorbing and desorbing sheet of the present invention has a natural texture unique to wood flour, and has excellent moisture absorbing and desorbing properties due to the wood flour and moisture permeable resin.
It is extremely effective in preventing condensation and has a soft, warm texture. It also has excellent stain resistance, flexibility and stretchability, and can be applied to a wide variety of uses that require moisture absorption and desorption properties and stain resistance.

Moreover, the manufacturing process is simple and can be manufactured at low cost.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of the moisture absorbing and releasing sheet of the present invention. (1) Moisture-permeable resin, (2) Wood flour. Patent applicant: Toyo Rubber Industries Co., Ltd. Agent: Yoshiyuki Koyama, patent attorney

Claims (2)

[Claims] (1) A moisture-absorbing and desorbing sheet made by embedding wood powder in a moisture-permeable resin layer. (2) A solution or emulsion of moisture-permeable synthetic resin and wood flour are uniformly mixed, the resulting compound is uniformly applied to the surface of the base material, and after heating and drying, it is peeled off from the base material and formed into a sheet. The method for producing a moisture absorbing and releasing sheet according to claim 1.