JPH05154331A - Moisture absorbing material - Google Patents

Abstract

PURPOSE: To allow a moisture-absorbent material to be easily and simply attached to a wall where dew is condensed or which is wet at room temperature with respect to the moisture-adsorbent material in the form of a self-supporting tape, web or sheet having a water-absorbing layer comprising a highly water- absorbent polymer material by providing an attachment surface comprising a pressure-sensitive adhesive. CONSTITUTION: The moisture-absorbent material is formed into a self-supporting tape, web or sheet having a water-absorbing layer comprising a highly water- absorbent polymer material (example, acrylic acid) provided by an attachment surface comprising a pressure-sensitive adhesive (example, acrylic base adhesive). Thereby a user can attach the material easily to a wall where dew is condensed or which is wet at room temperature.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to moisture absorbers. In particular, the present invention relates to a moisture absorber in the form of a self-supporting tape, web or sheet, comprising a water-absorbent layer comprising a highly water-absorbent polymeric material and a surface comprising a pressure sensitive adhesive.

[0002]

BACKGROUND OF THE INVENTION A problem that has always been a problem with windows, and especially with single-sided windows, is dew condensation. In cold weather, the inner surface of the window
Often the temperature is lower than the air inside the building. When warm, moist air comes into contact with this cold glass, the moisture condenses on it and flows down the window glass. It is unsightly and eventually rots wooden window frames and corrodes adjacent decorations. Furthermore, during cold weather, the supply water is at a much lower temperature than the air inside the building. For this reason, dew condensation occurs on a water tank for hand-washing, a pipe, a faucet, etc., especially on a water tank of pottery. This condensed water spills on the floor, creating an unsightly puddle on a non-absorbent floor such as linoleum, or creating an impregnated portion on an absorbent floor such as carpet.

Since almost nothing can be done to prevent condensation,
Attempts at solving this problem have focused on collecting water. For example, British Patent Specification No. 2045845 and US Patent Nos. 4,064,666, 4,065,884,
And 4,408,425 and the like describe various devices that are attached to the bottom of windows to collect dew. These devices generally include associated structures that include absorbent material that can be removed when saturated or saturated. However, such devices are bulky and highly visible and do not easily fit into windows of various sizes and shapes.

The water-absorbent foam strip is Spontex.
Commercially available from the company. This is placed at the bottom of the window to absorb the water flowing down the window glass and collect it in the lower frame. Due to its limited absorption capacity, this foam material must be periodically removed from the lower frame when saturated and squeezed by hand. As a result, the strip becomes distorted, twisted, improperly repositioned when dried and is rather unsightly.

European Patent Specification No. 59062 discloses a caulking material having a second non-swelling, rubbery layer laminated with a dispersion of water-absorbing polymer particles in a rubbery matrix. This material can be prepared in the form of sheets of unit size or in the form of long continuous sheets rolled up. And it is designed to swell in one direction when it comes into contact with moisture to form the voids of the cracks.

European Patent Publication No. 262230
A ribbon-shaped laminate of a high melting point polymer and a low melting point polymer, the latter low melting point polymer discloses a water absorbent composite having water absorbent particles fused to its surface. The laminate may be slit into yarns and further processed into useful articles or used as water absorbing ribbons, for example as part of a telecommunications table and protective sheath for optical fibers.

[0007] Japanese Patent Application No. 1-129087 is a water-stop tape in which absorbent polymer particles and a filler-free material are dispersed in an organic binder and applied to a paper or a film. What is used to do this is disclosed.

Canadian Patent Specification No. 1220638
It discloses a porous canopy in the form of a bag, tube or the like, for example a superabsorbent material wrapped in a cloth, which swells in contact with water and is used as a substitute for a flood protection sand bag.

[0009]

SUMMARY OF THE INVENTION According to one aspect of the present invention, a self-supporting tape, web or sheet having a highly water-absorbent polymeric material and a mounting surface containing a pressure sensitive adhesive is provided. A shaped moisture absorbent material is provided.

The present invention is a moisture absorbing material (hereinafter simply referred to as "material") that can be easily and easily attached by a user to a surface that easily condenses, such as a window, or a surface that is normally wet, such as a bathroom wall. )I will provide a. The material can absorb and retain large amounts of water and at least substantially prevent the above mentioned problems. The absorbed water is then released into the atmosphere for extended periods of time, typically hours, without the need for material removal.
The release rate depends on the ambient temperature and humidity (and the ease with which air can permeate the water-absorbing layer). The material can be removed from the surface when it becomes dirty or no longer needed and is advantageously reused.

Therefore, according to another aspect of the present invention, there is provided a method of rendering a surface moisture absorbent, comprising applying the moisture absorbent material of the present invention to the surface.

The material generally comprises a support which imparts mechanical strength to the structure, the support having a water absorbing layer on one side and an adhesive mounting surface on the other side. The material itself can absorb many times its weight in water, and generally has an absorption capacity of at least 10. This absorption capacity is
It is represented by [(saturated weight of material)-(dry weight of material)] / (dry weight of material).

Preferably the material has an absorption capacity of at least 2
It is 0, more preferably at least 50.

The water-absorbent layer generally comprises a layer of porous material forming a water-permeable matrix in which a highly water-absorbent polymeric material is dispersed or contained. Suitable porous materials include non-woven webs such as cloth, and polymer foams such as polyurethane or polyamide foams.

Polymeric materials that strongly absorb water are known. Such materials include naturally occurring materials.
For example, various gums. Alginates, pectins and gelatins (eg Rompps Chemie-Lex).
ikon 8th Edition, Volume 2, P.I. 1559/2558. These materials are generally cross-linked by methods known in the art so that they are capable of absorbing water and are not colloidal solutions.

Preferred superabsorbent polymer materials for use in the present invention are fully synthetic materials such as homopolymers of acrylic acid or methacrylic acid (or other modified acrylic acid) and one or more of acrylic acid or methacrylic acid. Of ethylenically unsaturated monomer. The carboxyl groups of these crosslinked polymers may be in the form of monovalent salts, especially in the form of alkali metal salts. Such materials are known and cross-linked polyacrylates such as those available from Allied Colloids under the trade names SALSORB and ALCOSORB, starch-acrylic acid graft copolymers such as Hoechst Ce under the trade name SANWET.
commercially available from Lanese, and saponified acid-vinyl acetate copolymers.

A suitable water-absorbing polymer is US Pat. No. 3,
983,095, 3,954,721, 4017,65
3 and 4,018,951. Such materials are used in disposable diapers and related products and in absorbent sheets for food packaging. These are disclosed, for example, in Japanese Patent Nos. 62-286725 and 63-267545.

They are known in the art as "superabsorbents" or "superabsorbent polymers". It is especially a copolymer of acrylic acid or methacrylic acid with acrylamide, methacrylamide or acrylonitrile, eg German patent specification No. 270613.
5 and are commercially available under the trade name FAVOR.

Other superabsorbent polymer materials suitable for use in the present invention are crosslinked polymers and copolymers of ethylene oxide and propylene oxide.

The highly water-absorbing polymeric material preferably has, as its monomer component, one or two carboxyl groups (or groups which can be converted into carboxyl groups, such as carboxylates, carboxylic acid amides, carboxylic acid imides or carboxylic acid groups). It is a polymer containing an α, β-unsaturated compound including an acid anhydride). Suitable α, β-unsaturated compounds include, for example, acrylic acid, methacrylic acid, acrylamide, methacrylamide, maleic anhydride, maleic acid,
There are maleamide, maleamic acid, maleimide, itaconic acid, crotonic acid, fumaric acid and mesaconic acid.

This superabsorbent material is not only a mixture of an α, β-unsaturated compound and one or more other copolymerizable monomers, but also two or more, as long as the desired water absorption performance is obtained. It may be a mixture of different types of α, β-unsaturated compounds. Suitable copolymerizable monomers include α-olefins, vinyl compounds and vinylidene compounds such as ethylene, propylene, isobutylene, 1-butylene, diisobutylene, methyl vinyl ether, styrene, vinyl acetate, acrylic esters, methacrylic esters, acrylonitrile and methacrylic acid. There is ronitrile. When the superabsorbent polymer material is a copolymer of a carboxyl-containing α, β-unsaturated monomer and a copolymerizable monomer, the material preferably contains at least 40 mol% α, β-unsaturated compound.

Preferred superabsorbent materials include polymers of acrylic acid and methacrylic acid (and other modified acrylic acids), and copolymers of α-olefin or vinyl compounds with maleic anhydride.

The superabsorbent polymer material can be prepared by a known method using a radical polymerization initiator. This material generally has a degree of polymerization range of generally 10-5000.

The water affinity of the polymeric material is determined by the basic compounds, such as alkali metals, such as sodium, potassium or alkaline earth metals, such as magnesium, calcium or barium, ammonia, or hydroxides, oxides or carbonates of monoamines. Can be further increased by reacting with. The basic compound is generally mixed with stirring with a solution of the polymeric material in a suitable solvent, preferably water. Preferred basic compounds are sodium hydroxide, potassium hydroxide and ammonia. That is because they are highly reactive and increase the water absorption durability of the product.

The polymeric material containing the α, β-unsaturated compound may then undergo a crosslinking reaction. Suitable crosslinking agents for this reaction include polyhydric epoxy compounds, polyhydric amines, polyhydric alcohols, amino alcohols, polyisocyanates and polyhydric halohydrins. Polyvalent epoxy compounds and polyvalent amines are preferred. That is because they provide the polymeric material with durability and high water absorption.

Suitable polyhydric epoxy compounds include glycerin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin triglycidyl ether, propylene glycol diglycidyl ether, polypropylene diglycidyl ether and trimethylolpropane triglycidyl. There is ether. Suitable polyamines include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and polyethyleneimine, generally with a molecular weight of less than 5000. Although optional, it is preferred to crosslink the polymeric material in the practice of the present invention.

The cross-linking reaction is generally carried out by mixing a polymeric material containing the α, β-unsaturated compound with a cross-linking agent and optionally heating or optionally adding a solvent. For example, when using a polyvalent epoxy compound or a polyvalent amine as a crosslinking agent, it is preferable to heat the reaction mixture in the presence of water. The product of the crosslinking reaction is usually dried or further heat treated. The degree of cross-linking is adjusted (by adding an appropriate amount of cross-linking agent) so that the superabsorbent polymer material obtained has the desired water absorption ratio.

Examples of preferred superabsorbent polymer materials used in the present invention are shown below.

(1) Maleic acid or related compounds (ie,
Derivatives of maleic acid such as maleic anhydride, maleamide or maleimide) and generally having 2 to 1 carbon atoms
2, preferably a copolymer containing 2 to 8 linear or branched α-olefins (for example, ethylene, propylene, butylene, isobutylene or diisobutylene) and a basic compound such as an alkali metal compound or an alkaline earth metal. A material obtained by reaction with a compound, ammonia or a monoamine, optionally crosslinked.

(2) Copolymers containing maleic acid or related compounds and vinyl or vinylidene compounds (for example, styrene, vinyl acetate, methyl vinyl ether, acrylic acid esters, methacrylic acid esters, acrylonitrile or methacrylonitrile) and basic compounds. For example, a material obtained by reacting with an alkali metal compound, an alkaline earth metal compound, ammonia or a monoamine, optionally cross-linked.

(3) optionally crosslinked with a material obtained by reacting a polymer of acrylic acid or modified acrylic acid (eg methacrylic acid) with a basic compound such as an alkali metal compound, an alkaline earth metal compound, ammonia or a monoamine. thing.

(4) A copolymer containing acrylic acid or modified acrylic acid and one or more of the vinyl or vinylidene compounds described in (2) above and a basic compound such as an alkali metal compound, an alkaline earth metal compound or ammonia. Alternatively, a material obtained by reacting with a monoamine, optionally crosslinked.

Particularly preferred are cross-linking materials obtained by reacting a copolymer containing isobutylene and maleic anhydride with sodium hydroxide, potassium hydroxide or ammonia, and polyacrylic acid and sodium hydroxide. The material used is a crosslinked polyacrylic acid. This is because it has excellent water absorption and durability.

Preferred water-absorbing polymeric materials have an absorption capacity of at least 20, preferably at least 100, based on their dry weight, as measured by the test methods described below.

Examples of suitable water-absorbing layers are: non-woven webs prepared from fibers impregnated with SALSORB or ALCOSORB commercially available from M & J Paper Company; polyurethane foam with modified starch superabsorbent. Packed with materials, Hoech
SA commercially available from st Celanese
NFOAM ™, and polypropylene and Arco
A range of non-woven webs including blends with FIBERSORB ™ super absorbent fibers, commercially available from Chemical Company.

Superabsorbent polymeric materials are usually formed as particles or fibers. Most other forms are useful as long as they provide a large surface in contact with water. The particle size distribution of the polymeric material is important. It is because particles that are too small will leach out of the porous material, and relatively large particles with a low surface area: volume ratio will form a tightly packed gel layer on the surface and prevent further water infiltration. is there. Generally, at least one dimension of the polymeric material should be small enough to ensure rapid absorption of water.

When the polymeric material is formed as particles, its average diameter is generally 10 to 1000 μm, preferably 50 to 500 μm, more preferably 50 to 300.
μm. When the polymeric material is formed as fibers, its average length is generally 50 to 1000 μm, preferably 200 to 500 μm.

The hygroscopic material of the present invention comprises a water-absorptive layer formed by a conventional double-sided tape such as 3M Type 415 (trademark).
It is manufactured by laminating it on a support such as an adhesive tape. The 3M Type 415 (trademark) adhesive tape is a polyethylene terephthalate film coated with an acrylic-based pressure-sensitive adhesive by a method well known in the tape manufacturing industry.

The adhesive mounting surface may be directly adhered to the self-supporting water-absorbent layer by means of an adhesive transfer material, but it is preferable to have adhesive on both sides and to bond one side to the water-absorbent layer, A structure in which one surface is protected by a peelable carrier sheet is preferable.

The support may be made of any of the materials commonly used in tape making, such as tissue, paper or polymer film. Carrier sheet typically has a release layer, such as poly (vinyl chloride -. Comprising a support having those containing SiO ₂ particles optionally with a layer of vinyl acetate such materials are well known in the art.

The adhesive used to bond the water-absorbent layer to the support is preferably a pressure sensitive adhesive that provides a permanent bond between the two and is not adversely affected by wet conditions. The mounting surface may include a continuous or discontinuous layer, desirably a pressure sensitive adhesive that can be firmly bonded to the glass in the wet state, but that can be peeled off from the glass when needed. The mounting surface adhesive may be any pressure sensitive adhesive known in the art, but acrylic based or modified acrylic acid based adhesives are preferred.

The hygroscopic material of the present invention is preferably in the form of a long tape or web, conveniently wound on itself or on a spool in the form of a roll. In use, the user can then simply strip the desired length of material from the roll and cut the carrier sheet, if any, prior to use. The web or tape is generally 1-5 cm wide, typically about 2.
5 cm, which is suitable for most household applications. The roll may contain any length of hygroscopic material, but is preferably at least 5 m.

Alternatively, the hygroscopic material may be formed as individual strips. Under the hand wash tank,
The hygroscopic material may be made in sheet form when a relatively large surface area has to be covered, such as a bathroom wall. The size of the sheet depends largely on the surface area to be coated, but at least A3 to A10 (ie 297 x 420 mm).
~ 26 x 37 mm), preferably A3 to A5 (ie 297)
X 420 mm to 148 x 210 mm) can be considered.

[0044]

EXAMPLES The present invention will be described below with reference to examples. M
innesota Mining & Manufact
uring Co. 3M Type 415 ™, which is a commercially available polyethylene polyethylene terephthalate film coated with acrylic-based pressure sensitive adhesive on both sides.
A series of hygroscopic tapes was prepared by laminating a double-sided adhesive tape with a water-absorbing layer containing a suitable water-absorbing polymeric material. A strip of each tape was attached to the inner wall of a beaker of known weight. It was then re-weighed and filled with sufficient distilled water to completely dip the tape. After allowing the tape to penetrate for 5 minutes, distilled water was poured out, the beaker was inverted, and the water was drained for another 5 minutes. The beaker was then carefully dried and weighed without touching the saturated tape sample. This allows the absorption capacity of the tape to be calculated. This was expressed as the ratio of the weight of absorbed water to the dry weight of the tape.

(Absorption capacity) = [(saturated tape weight)-
(Dry tape weight)] / (Dry tape weight)

Example 1 This example is based on M & J Paper Co. Various absorbent materials supplied by (they are called by their trade name)
And Minnesota as an example of unmodified foam tape
Mining and Manufacturing
Co. Commercially available from 3M Draught
Test the Extruder ™. Of the M & J materials, MJ1, MJ2 and MJ14890911 contain superabsorbent powders, the rest are standard nonwoven absorbent webs such as kitchen towels, table napkins and the like. The absorption capacity of these materials is shown in Table 1.

[0047]

The moisture-absorbing tape of the present invention, ie, MJ1, MJ2 and MJ1489091 containing superabsorbent powder.
1 shows a clear advantage over the standard absorbent web.

Example 2 This example illustrates the use of different types of absorbent materials. The material is Arc under the trade name FIBERSORB.
o Chemical Co. Is a blend of polypropylene and super absorbent fiber commercially available from Samples 1-3 shown below have different weights (8.5 x
10 ^-2 , 1.7 x 10 ^-1 and 3.4 x 10 ^-1 kgm ^-2 ) and absorbent content (25, 10 and 30% w / w respectively)
With different grades of materials. The absorbency of these materials is shown in Table 2 below.

[0050]

As expected, the absorption capacity increases with increasing amounts of absorbent material used.

Example 3 This example illustrates the use of foam-based media for superabsorbent particles. Samples 1 and 2 below are Hoechst C
Two grades of SAMFOAM absorbent material commercially available from elanese, consisting of polyurethane foam filled with 24% by weight polyacrylate modified starch. The two grades differ only in the surface treatment applied to the foam. The absorption capacity of these materials is shown in Table 3.

[0053]

* Sample 2 returned to the original weight within 48 hours when left at 20 ° C. and relative humidity of 50%.

"ALCOSORB" (Allied C
olloids), “FAVOR”, “FIBERSO”
RB ”(Arco Chemical Co.),“ S
ALSORB "(Allied Colloids),
"SAMFOAM" (Hoechst Celanes)
e) and "SANWET" (Hoechst Cela)
Nese) are all trade names.

[0056]

According to the present invention, there is provided a moisture absorbing material which can be easily and easily attached by a user to a wall which is liable to be condensed or which is normally wet.

Claims (3)

[Claims] 1. A moisture-absorbing material in the form of a self-supporting tape, web or sheet, having a water-absorbing layer comprising a highly water-absorbing polymeric material, said material comprising a pressure sensitive adhesive. Characterized by having a mounting surface. 2. The material of claim 1 including a support having a water-absorbent layer coated on one side and an adhesive mounting surface on the other side. 3. A method of rendering a surface moisture absorbent comprising applying the moisture absorbent material of claim 1 or 2 to the surface.