JPH02279324A - Humidity conditioning foamed sheet and preparation thereof - Google Patents

Abstract

PURPOSE:To obtain a sheet excellent in moisture absorbing and release properties, antistaining properties and touch by laminating and fixing a moisture permeable closed-cell resin foamed layer to a base material such as paper or a plastic sheet. CONSTITUTION:A foam layer 1 composed of a foamed moisture permeable synthetic resin 3 such as polyurethane foam is formed to a base material 4 such as paper or a plastic sheet and, if necessary, a moisture absorbent is dispersed and embedded in said resin. The moisture permeable resin 3 is soluble in a solvent and hard to swell in water and has film forming properties and, for example, there are a vinyl alcohol resin, a vinyl acetate resin or the like. By this method, a moisture conditioning foamed sheet excellent in moisture absorbing and release properties, pleasant to feel or touch, having excellent softness and antistaining properties and also having anti-slip properties and antistatic properties is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a humidity control foam sheet and a method for manufacturing the same.

[Prior Art] Regarding interior materials for indoor rooms, stores, automobiles, ships, elevators, transportation equipment such as food, etc., issues regarding humidity control and prevention of dew condensation are considered important.

Currently, interior materials made of vinyl chloride are mainly used.

[Problem to be solved by the invention] However, although vinyl chloride does not easily get dirty and is easy to wipe off even if it gets dirty, it does not absorb moisture, so it is very prone to condensation, and its surface gloss and texture are not desirable. do not have. Although interior materials made of paper or textiles have moisture absorbing and desorbing properties, they tend to get dirty, and it is difficult to wipe away the adhered dirt.

Especially OA equipment such as computers and word processors, optical equipment such as microscopes and cameras, home appliances such as telephones, televisions, stereos, and video cameras, kitchen utensils such as cabinets, sinks, and cupboards, and office equipment such as furniture, desks, chairs, and bookshelves. , stationery such as albums, book covers, notebooks, office supplies, bags, bags, packages, etc. have traditionally not had moisture absorption or release properties, so they tend to sweat easily when used, feel stuffy, and have poor texture and texture. Cold and undesirable. It also tends to generate static electricity and is prone to flaking.

[Means for Solving the Problem] In order to achieve the above object, the inventors of the present invention have conducted intensive research, and as a result, they have developed a method of foaming a moisture-permeable synthetic resin such as polyurethane on the surface of a base material such as paper or plastic sheet. By forming a foam layer and dispersing and embedding a moisture absorbent in the resin as necessary, it has excellent moisture absorption and desorption properties, is warm to the touch, soft to the touch, has excellent stain resistance, and has excellent anti-slip properties. It was discovered that a moisture-controlling foam sheet that also prevents static electricity can be obtained. Furthermore, this foam layer is created by applying a moisture-permeable resin containing microcapsules containing a vaporizable liquid and optionally a moisture-absorbing powder to the surface of a base material such as paper or plastic sheet, and then heating and foaming it. They discovered scales that can be formed extremely easily and completed the present invention.

That is, the gist of the present invention is a humidity control foam sheet characterized by laminating and fixing a moisture permeable resin foam layer consisting of substantially closed cells on the surface of a base material such as paper or plastic sheet.

Furthermore, in the present invention, thermally expandable microcapsules formed by embedding a vaporizable liquid in a thermoplastic resin film are mixed with a moisture permeable resin and, if necessary, a moisture absorbent, and the resulting compound is applied to the surface of the above-mentioned base material. The gist of this invention is a method for producing a moisture-controlling foam sheet, which is characterized by applying a moisture-controlling foam sheet to a foam and heating and foaming it.

The moisture-permeable resin used in the present invention is not particularly limited as long as it is soluble in a solvent, does not swell easily with water, and has film-forming ability, but examples include vinyl alcohol-based resins and vinyl acetate-based resins. Resin, acrylic resin, urethane resin, amino acid resin, etc., and JIS
Film measured by Z-0208B method (film thickness 10μ
) has a moisture permeability of 1000 g/m2-2411 or more. These resins are usually used dissolved in a solvent or in the form of an emulsion, but in this case, the solid content in the solution is 10 to 50% by weight, and the solution viscosity is 10%.
It is adjusted to 0 to 7000 cps.

Next, heat-expandable microcapsules and, if necessary, a moisture absorbent and other additives are suitably added to this solution and mixed uniformly to prepare a compound.

The thermally expandable microcapsules used in the present invention are microspheres in which a vaporizable liquid is embedded in a thermoplastic resin film, and when heated to an appropriate temperature, the embedded liquid vaporizes and the pressure increases. The entire capsule expands, giving a foam with expanded volume (hereinafter abbreviated as foaming). The thermoplastic resin constituting the microcapsules preferably has a softening point of 50 to 200°C, and this type of resin includes:
Examples include homopolymers such as polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polymethylamylate, polymethylmethacrylate, polyvinyl acetate, copolymers thereof, and mixtures thereof.

As the vaporizable liquid to be embedded, lower hydrocarbons such as liquefied butane, which can be easily microencapsulated and are inexpensive, are suitable. The particle size of microcapsules before foaming is 5~
30μ, and has the property of foaming several times to several tens of times more when heated at 50 to 200°C for several minutes.

The mixing ratio of the thermally expandable microcapsules and the moisture-permeable resin described in Section 2 is in the range of 2 to 500 parts by weight, preferably 5 to 200 parts by weight, of the microcapsules per 100 parts by weight of the resin solid content in the solution. If it is less than 2 parts by weight, it will lack a soft feel after foaming, and if it is more than 500 parts by weight, the strength of the moisture permeable resin foam layer will be weak and the moisture permeability will be impaired, which is not preferable. When mixing the microcapsules, it is important to uniformly mix and disperse them using an appropriate method such as Daysilver homodisbur or paint roll.

The hygroscopic agent used in this invention is a commercially available polymeric hygroscopic agent or an inorganic hygroscopic agent, and
Any material can be used as long as it exhibits moisture absorption and desorption performance depending on the environment, and these materials can be used alone or in combination.

Preferred polymeric moisture absorbents include polyacrylate-based,
Carboxymethyl cellulose, inbutylene-maleic acid copolymer, starch-acrylic acid graft polymer, saponified vinyl acetate-acrylic acid ester copolymer, saponified vinyl acetate-unsaturated dicarboxylic acid copolymer, polyethylene oxide, etc. Examples include natural valves, leather, etc. The particle size of these polymeric hygroscopic agents is usually 20 μm or less, and the finer the particle size, the better the moisture absorption and desorption performance will be. In addition, bentonite, silica, sepiolite, calcined talc, zeolite, various other inorganic salts, and natural stone powder with adsorption properties are used as inorganic hygroscopic agents, but the finer the particle size, the larger the surface area, and the more absorbent. It is preferable because it has good moisture release performance.

The amount of these moisture absorbers added is usually in the range of 10 to 300 parts by weight per 100 parts by weight of resin solid content in the solution.

In carrying out this invention, in addition to the above-mentioned compounding agents, various pigments, weathering agents, deodorizing agents, fragrances, antifungal agents, and the like may be added as appropriate.

As a method for applying the compound prepared by mixing the various compounding ingredients as described above to a base material such as paper or plastic sheet, generally known coating methods such as gravure coating, doctor blade, and reverse roll coating may be adopted as appropriate. sell. Furthermore, for thermoplastic resins, methods such as extrusion coating can be applied without using a solvent.

Paper, woven fabric, non-woven fabric, felt, plastic sheet and film, leather, metal foil, etc. can be used for the base material.

The thickness of these base materials is usually 10 to 5000μ,
When the compound is continuously applied to a constant thickness of 10 to 100 microns on top of this and heated to a predetermined temperature, the microcapsules foam to form a moisture permeable resin foam layer with a thickness of 15 to 1000 microns. The heating temperature during foaming is appropriately selected depending on the material of the microcapsules used, but usually 50 to 200°C is used, and heating at this temperature for several minutes (for example, 1 minute at 120°C) will scatter the solvent. At the same time, foaming occurs, followed by cooling and molding is completed. In addition, the process of blowing off the solvent and the foaming process are separated, and
It can also be formed in stages. Foaming may be done by free foaming, but it is also possible to control the foaming thickness by pressing from above with a release paper in an appropriate manner.

In addition, various methods can be used to decorate the surface, such as embossing the coated surface after molding, printing various colors and patterns, and even using a pre-printed base material.

[Function] The sheet of the present invention is a moisture-controllable foam sheet in which the base material such as paper or plastic sheet is coated with a moisture-permeable resin foam, and the moisture absorption and desorption cycle is quick depending on the environment. By adding a hygroscopic agent to the foam, the dew condensation prevention effect can be further improved.

In sheets with such a structure, when the humidity is high, water vapor penetrates into the moisture permeable resin layer or into the moisture absorbent and is occluded.
Furthermore, once the sheet is dry, the stored moisture is quickly released from the surface of the sheet, and the sheet can reversibly absorb and release moisture following changes in surrounding humidity, thus exhibiting a humidity buffering effect.

As a result of this moisture absorption and release action, dew condensation phenomenon is suppressed.

Furthermore, since the resin layer is made of foam, it has a heat insulating effect and is soft and warm to the touch.

In addition, the foam is substantially composed of closed cells, and its surface is non-porous, so it does not get clogged even if dirt adheres to it.
Dirt can be easily wiped off with a dry cloth or wet cloth, so the beauty can be maintained for a long time and moisture permeability does not deteriorate.

By applying a pressure-sensitive adhesive, adhesive, etc. to the back surface of the sheet of the present invention, adhesion, etc. at the time of pasting can be easily performed. The seat of the present invention can be used indoors, stores, automobiles, ships, elevators,
Transportation equipment for food, interior materials for equipment, computers, word processors, optical equipment such as microscopes, cameras, home appliances such as telephones, televisions, stereos, video cameras, etc.
Kitchen utensils such as cabinets, sinks, and cupboards, office equipment such as furniture, desks, chairs, and bookshelves, stationery and office supplies such as albums, book covers, and notebooks, bags, bags, packages, shoe insoles, stairs, floors, etc. It can be used for a variety of purposes, such as sheets laid on floors.

[Example] Moisture-permeable urethane resin (manufactured by Toyo Rubber Industries, Ltd.: NY814)
The moisture permeability of a 20 μm thick film formed from a solution by a casting method was 4300 g/G·241+. Next, thermally expandable microcapsules (trade name: Microsphere-F-) were added to this solution per 100 parts by weight of the solid content.
50D (manufactured by Matsumoto Yushi Seiyaku KK) was added at a ratio of 50 parts by weight and mixed uniformly using a paint roll to prepare a compound. This compound is applied uniformly onto a vinyl chloride sheet (thickness 120μ) using the gravure coating method, heated and foamed at 120°C for 1 minute in a heating furnace, and then cooled to form a material that is virtually independent on the surface of the base material. A layer of moisture permeable resin foam made of air bubbles is laminated and fixed to a thickness of 50 mm.
A sheet of 0μ was obtained.

The drawing is a sectional view showing the structure of a humidity control foam sheet obtained by the above method. In the figure, (1) is a moisture-permeable urethane resin foam layer, (2) is a closed cell formed by foaming expandable microcapsules, (3) is a moisture-permeable resin made of a urethane polymer, and (4) is a vinyl chloride sheet.

When we made book covers and bags using the above sheets and put them into practical use and compared them with conventional vinyl ones, we found that the parts of the vinyl ones that were held in the hand got sweaty and felt stuffy. Ta. However, the sheets made from the sheets of the present invention did not feel stuffy and had a good texture and were easy to use.

[Effects of the Invention] Conventional materials such as vinyl chloride do not have moisture absorption and desorption properties and are prone to condensation and stuffiness, while paper and textiles are easily stained and cannot be wiped away. It can be said to be an extremely excellent sheet with excellent moisture dissipation and stain resistance, a matte texture, and a pleasant touch.

[Brief explanation of drawings]

The drawing is a cross-sectional view showing one embodiment of the humidity control foam sheet according to the present invention. (1)...Moisture permeable urethane resin foam layer (2)...
Closed cell foam (3)... Moisture permeable resin (4)... Vinyl chloride sheet

Claims (2)

[Claims] (1) A humidity control foam sheet characterized by having a moisture permeable resin foam layer consisting of substantially closed cells laminated and fixed on the surface of a base material such as paper or plastic sheet. (2) A thermally expandable microcapsule made by embedding a vaporizable liquid in a thermoplastic resin film, a moisture-permeable resin, and, if necessary, a moisture absorbent, are mixed uniformly, and the resulting compound is applied to the surface of the base material. A method for producing a moisture control foam sheet, which comprises coating the sheet and heating and foaming it.