WO1997000301A1

WO1997000301A1 - Dew condensation preventive material

Info

Publication number: WO1997000301A1
Application number: PCT/JP1996/001634
Authority: WO
Inventors: Mitsuru Akashi; Takamasa Harada; Toshiaki Nonaka; Ikuo Imaizumi
Original assignee: Hoechst Industry Limited
Priority date: 1995-06-16
Filing date: 1996-06-14
Publication date: 1997-01-03
Also published as: JPH093439A

Abstract

A material for effectively preventing dew condensation on, for example, the surface of the interior wall of a building when, for example, it is placed between the interior and exterior walls or composited with wall paper or gas-permeable base material. The preventive material comprises a heat-sensitive and highly water-absorbent polymer which reversibly absorbs and releases moisture with a temperature change and mainly comprises a polymer of N-vinylisobutyramide or derivatives thereof.

Description

Description Dew condensation prevention material Technical field

TECHNICAL FIELD The present invention relates to a dew condensation preventing material, and more particularly, to a material suitably used as a building material or the like. For example, the material is placed between an outer wall and an inner wall or is combined with wallpaper to form dew condensation on a surface such as an inner wall. And a material that effectively prevents More specifically, it is preferably used as a dew-prevention material in places where dew condensation is likely to occur, such as ceilings, closets, attics, backs of evening baths, flower arrangements, basements, air conditioners, toilets, bathrooms, and refrigeration. is there. Background art

In recent years, building materials, especially concrete and mortar materials, have been widely used for the outer walls and floors of buildings due to their excellent mechanical strength. However, unlike concrete and concrete materials, unlike wood, etc., they have poor moisture absorption and desorption properties, and the problem of dew condensation has arisen based on the difference between the outside temperature of the building and the room temperature. In other words, the humid and warm air in the room is cooled near the inner wall by the outside air temperature and falls below the dew point, forming water droplets and condensing. Therefore, there have been problems such as mold and mite tending to occur on the inner wall.

On the other hand, for the purpose of isolating the outside and indoor temperatures of the building, heat insulating materials such as glass rolls are placed between the outer and inner walls. It is also widely used in buildings that use timber and timber. In summer, it is to reduce the influence of outside air, and in winter, it is to improve indoor heating efficiency.

However, even with such a heat insulating material, there is a problem of dew condensation. There is a problem that the heat insulation effect is significantly reduced when moisture is condensed, and there is no escape of moisture after dew condensation.Therefore, there is a problem that once the dew condensation forms, it is practically difficult to recover the heat insulating function. Was.

Therefore, it has been proposed to use a water-absorbing polymer as a dew condensation preventing material. For example, Japanese Unexamined Patent Publication (Kokai) No. 6-16403 proposes a dew condensation preventing sheet using acrylic acid or an alkali metal salt of acrylic acid. However, such a material has a small water absorption capacity of, for example, 5 to 25 times, has poor absorption of a large amount of dew water, and is quickly saturated, and once saturated, can exhibit a further dew condensation preventing effect. There was no problem. Also, when the absorbed moisture becomes saturated, the polymer becomes more likely to fall off from the wall material as a substrate to which the polymer is attached, or the absorbed moisture causes the weight of the wallpaper or the like to increase. There were also problems such as the adhesive strength between the wallpaper and the wall being reduced and the wall being easily peeled off.

Also, Japanese Patent Application Laid-Open No. 6-158032 discloses an acrylic synthetic resin emulsion, a vinyl acetate synthetic resin emulsion, or a copolymer emulsion of both of them and a fluorine synthetic resin emulsion. Coating agents containing silicone-based synthetic resin emulsions as main components have been proposed.

However, the water absorption of such materials is up to about 30 times, which means that they have poor anti-fungal properties, use a large amount of fungicides in combination, and lack safety, and furthermore, have a long-term usability. The problem was scarce.

In addition, there was also a problem that the function of absorbing and releasing water, that is, the function of adjusting the water content was insufficient, resulting in poor antifungal properties. In addition, fluoroplastic synthetic resin emulsion or silicone synthetic resin emulsion is used, and lacks transparency due to poor compatibility with acrylic synthetic resin emulsion-vinyl acetate synthetic resin emulsion. When used on a surface or the like, there are problems such as impairing the appearance, non-uniform dew condensation prevention characteristics, and high cost.

The present invention has been made in view of the conventional problems, and a specific heat-sensitive superabsorbent polymer has an excellent water absorption ratio, specifically, a value of 1 to several 100 times. Sensitive to changes in temperature, remarkably affected by humidity, reversible absorption and release of moisture It was found to be used as a dew-prevention material, which is preferably used as a building material.

That is, the present invention provides a material that is placed between, for example, an outer wall and an inner wall, or that is compounded with a wallpaper or a permeable base material, and that effectively prevents dew condensation on a surface such as an inner wall of a building. The purpose is. Disclosure of the invention

The present invention is a dew condensation preventing material characterized by using a heat-sensitive highly water-absorbing polymer that reversibly absorbs and releases moisture with a change in temperature as a main component of the dew condensation preventing material. Hereinafter, the present invention will be described by dividing into components and the like.

(Heat-sensitive superabsorbent polymer)

In the present invention, it is an essential requirement that the heat-sensitive superabsorbent polymer be used as a main component of the dew condensation preventing material. Here, the heat-sensitive superabsorbent polymer exhibits a water-regulating function, and takes in and absorbs a large amount of water into the polymer at low temperatures, and releases the taken water at high temperatures. It is defined as a polymer material bridge having a function. Specific examples of the heat-sensitive superabsorbent polymer include, for example, a polymer containing N-vinylacylamide as a monomer component or a derivative thereof as a main component, and in particular, N-vinylacylamide as N-vinyl. Homopolymers of isobutylamide and copolymers (copolymers) containing N-vinylisobutylamide as a monomer component are preferred.

It is also preferable that the heat-sensitive superabsorbent polymer is mainly composed of a co-polymer of N-vinylybutylamide and N-vinylacetamide. This is because such a polymer can freely change the temperature at which water is absorbed and released by selecting the ratio of co-loading units.

Further, the poly (N-vinyl isobutyl amide) or a derivative thereof, a copolymer of N-vinyl isobutyl amide and N-vinyl acetate amide, and the like are cross-linked using a divinyl compound. Is preferred. This is because such a polymer can be applied to a nonwoven fabric or the like. In addition, the divinylated compound is defined as a compound having two or more double ties which can be superimposed in a molecule. Specifically, N, N-methylenebisacrylamide, N.N- Preferred is at least one of the group consisting of methylene-bis-N-vinylacetamide, N, N-butylene-bis-N-vinylacetamide and derivatives thereof.

In addition, when used alone, even a polymer that does not exhibit heat sensitivity can be suitably used in the present invention if it is a polymer that exhibits heat sensitivity by adding an auxiliary agent such as a salt. Can be used. For example, a polymer in which a certain amount of sodium chloride, sodium sulfate, or the like is added to polyvinyl acetate, which does not exhibit heat sensitivity by itself, also exhibits a predetermined heat sensitivity, and its use is expanded. It is suitable for the present invention.

Next, the water absorption capacity of the heat-sensitive superabsorbent polymer will be described. The water absorption capacity of the specific heat-sensitive superabsorbent polymer in the present invention is preferably in the range of 1 to several 100 times. If it is less than 1 time, sufficient dew condensation prevention effect may not be obtained.On the other hand, if it exceeds 100 times, the change in thickness or length will become large when it is made into a sheet or the like. This is because the mechanical strength may be reduced. Further, from the viewpoint of further improving the balance, the water absorption ratio of the specific heat-sensitive superabsorbent polymer is optimally in the range of 5 to 50 times.

Examples of a method for synthesizing these heat-sensitive superabsorbent polymers will be described later in Examples 1 and 2.

Next, components other than the main components in the dew condensation preventing material of the present invention will be described. That is, polymers that can be preferably used in combination with a specific heat-sensitive superabsorbent polymer include polymers superposed from acrylic monomers, such as methyl acrylate, ethyl acrylate, and acrylamide. , Methyl methacrylate, etc., or other than acrylic monomers, but not vinyl acetate, vinyl chloride-vinyl acetate copolymer, cellulose nitrate, vinyl chloride, polyamide, polyvinyl formal, polyvinyl butyral, Inoxy resin, polyester resin, and crosslinkable phenol resin, epoxy resin and the like. In particular, acrylic materials are the most suitable in that they can easily change the glass sizing transition point of the anti-condensation material of the present invention, and have good compatibility. is there. Further, addition of a flame retardant, an antioxidant, an ultraviolet absorber, a colorant, an inorganic filler, an organic filler, metal particles, etc. is also suitable for the application. In particular, it is preferable to add a flame retardant such as a halogen-based or phosphorus-based flame retardant to a base used for building materials in order to prevent the building from spreading. It is also preferable to add an anti-condensation agent to materials utilizing the hydration reaction of cement such as concrete and mortar, and such a platform will only prevent condensation and improve the mechanical strength of concrete and mortar. This is suitable because it can be used as a wall material.

Further, in order to strengthen the anti-fungal property, it is also preferable to add a fungicide, a deodorant, an antibacterial agent and the like. Specific examples of the fungicide include isophthalate, pyridine, chlorine, organic thio, organic arsenic, silver, copper and other metal ion-containing substances.

According to the present invention, in order to obtain the same fungicidal effect, the amount of the fungicide, deodorant, antibacterial and the like can be reduced as much as possible. There is also an advantage that safety is improved.

(Breathable substrate)

In the present invention, it is also preferable to form a composite with a heat-sensitive superabsorbent polymer such as poly (N-vinylisobutylamide) and a gas-permeable base material. This is because there are advantages such as adding other functions such as new thermal properties and facilitating handling.

Here, as the air-permeable material, specifically, a method conforming to the JISL-109B method, preferably having an air permeability of 10 seconds or less, more preferably an air permeability of〗 seconds or less Sex. When the air permeability is less than or equal to 0 seconds, there is rapid air circulation, and when the air permeability is 1 second or less, the air circulation is better, which is suitable for the present invention. Further, as the air-permeable base material, a sheet-like fibrous base material is preferable from the viewpoints of handleability, ease of compounding, and the like, and examples thereof include woven fabric, nonwoven fabric, paper, and knitted fabric. In particular, nonwoven fabrics made from various fibers are the most suitable in terms of strength and the like. Furthermore, as a constituent material of the air-permeable base material, a hydrophilic fiber, a hydrophobic fiber or an intermediate thereof can be used. However, when a hydrophilic fiber is used, poly (N-vinyl isobutylamide) or the like can be used. The heat-sensitive water-absorbing polymer has higher adhesion than the water-absorbing polymer. On the other hand, the use of a hydrophobic fiber has the advantage that the risk of deterioration in insulation and the like is reduced.

Specifically, as the hydrophilic fiber, wood pulp, cotton, wool, rayon, acetate, vinylon, and the like are preferable, and as the hydrophobic fiber, polyester, acrylic, nylon, polyethylene, polypropylene, polyvinyl chloride, and the like are used. And the like, and for these purposes, these mixed textiles are used.

The method of compounding the air-permeable base material with the heat-sensitive superabsorbent polymer is not particularly limited. For example, printing, spraying, and impregnation of the heat-sensitive superabsorbent polymer on the air-permeable base material It is also preferable to laminate the coating, the coating, or the both in the form of a film. Further, it is preferable that the polymer or monomer thus adhered is dried or polymerized by a known means. This is because the adhesion between the air-permeable base material and the heat-sensitive superabsorbent polymer is improved.

For example, it is possible to polymerize using heat, light, electron beam, ultraviolet ray and the like, and it is also preferable to add a polymerization initiator and other additives such as a polymerization accelerator, if necessary. This is because polymers with a controlled molecular weight are available.

Next, the composite ratio of the air-permeable base material and the heat-sensitive superabsorbent polymer will be described. That is, in the dew condensation preventing material of the present invention, it is preferable that the heat-sensitive superabsorbent polymer is compounded into 100 to 500 parts by weight with respect to 100 parts by weight of the permeable base material. . If the amount of the heat-sensitive superabsorbent polymer is less than 10 parts by weight, the water absorption of the anti-condensation inhibitor may decrease or become non-uniform, while if it exceeds 500 parts by weight, handleability may increase. This is because there is a possibility that the air permeability may decrease. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a drawing showing the time response characteristics of the thermal sensitivity of NVIB polymer. FIG. 2 is a drawing showing a change in light transmittance with respect to a change in the temperature of NVIB polymer.

FIG. 3 is a diagram showing a change in light transmittance of the NVIB-NVA co-support body with respect to a temperature change. FIG. 4 is a drawing showing a change in the degree of gel swelling of the crosslinked product of NVIB-NVA copolymer with a change in temperature. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described specifically with reference to examples. However, the present invention is not limited to these examples.

(Example 1)

A Synthesis of poly (N-vinylisobutylamide) (NV I B)

NVIB polymer was synthesized by the following synthesis method.

0C ₃ H ₇

H +

_{1) CH3CHO + CHaCHzCHzOH + NH 2} C0CH (CH 3) 2 - CH3-CH + H 2 0

NHC0CH (CH _3):

NHC0CHCCH ₃ ) ₂ NHC0CH (CH ₃ ): 3) CH ₂ = CH (CH ₂ -CH)-

NHC0CH (CU ₂ NHC0CH (CH _{: j} )

Characterization of B N V I B polymer

1) Thermal response time response test

Water was poured into a container, into which NVIB polymer was placed, and further subjected to a cycle test every 12 hours in an oven at a temperature of 20 ° C and 40 ° C. The gel swelling of the NVIB polymer was examined by measuring the volume change. As a result, as shown in Fig. 1, at a temperature of 20 ° C, the gel swelling increased as the standing time increased due to the absorption of moisture, but at 40 ° C, this tendency was not observed. The time sensitivity of the polymer to heat was confirmed.

2) Thermal sensitivity test

Pour water into the container, put the NV IB polymer in it, place it in the oven, leave the NV IB polymer in the oven, and raise the temperature by 1 ° C from 5 ° C to 40 ° C. The light transmittance when the polymer was in equilibrium at each temperature was examined. Thereafter, the same experiment was performed while cooling the temperature from 40 ° C to 5 ° C. Here, the light transmittance of the NVIB polymer was measured using a photodiode. As a result, as shown in FIG. 2, a sharp change in light transmittance was observed around 25 ° C., and the thermal responsiveness of the NVIB polymer was confirmed.

When the light transmittance is 0%, it indicates that no water is present in the polymer. On the other hand, when the light transmittance is 100%, the maximum amount of water that can be contained in the polymer is indicated. Indicates that is present.

C Evaluation of dew condensation prevention characteristics

Immerse in the above-mentioned NV IB aqueous solution using a polypropylene nonwoven fabric as a breathable substrate. After immersion, the mixture was squeezed with a transient roller so that an appropriate amount of aqueous solution remained on the substrate. Then, it was dried in an oven at 120 ° C. for 1 hour to obtain a desired dew condensation preventing sheet (100 parts by weight of a breathable base material, 50 parts by weight of NV IB).

Then, the sheet was allowed to stand in an oven at 10 ° C., 90% RH and 5 hours, and an experiment for confirming dew condensation was performed using the sheet. As a result, dew condensation water was sufficiently absorbed, and no water droplets were observed on the sheet surface, and it was confirmed that the sheet sufficiently functions as a dew condensation prevention sheet. After that, the temperature around the sheet was raised to 25 ° C., and the sheet was allowed to stand for 1 hour. Then, a recovery experiment was performed to observe the appearance of the sheet. As a result, it was confirmed that the state returned to the initial state before the dew condensation experiment with the release of water. In addition, the same experiment was repeated 10 times, and it was confirmed that dew water was absorbed and released with good reproducibility.

(Examples 2 to 4)

A NV I B-NV A

First, N-vinylacetamide (NVA) was obtained by the following method.

0C ₃ H ₇

H +

1) CH3CHO CH:, CH ₂ CH _z 0H NH ₂ C0CH:-CH ₃ -CH + H ₂ 0

NHCOCH;

2) CH3-CH CH- ^ CH + CsHvOH

NHCOCH, NHCOCH: Next, from the NVIB monomer and the NVA monomer Solution polymerization was carried out using azobisisobutyronitrile (AI BN) as a platform initiator to obtain a NV 〖B-NVA copolymer.

The weight ratios of the charged NVIB monomer and NVA monomer were changed to 80/20 (Example 2), 60/40 (Example 3), and 50/50 (Example 4), and they were co-mounted.

Characterization of BNVIB-NVA copolymer

A heat sensitivity test was performed in the same manner as in Example 1, and the heat sensitivity of the NVIB-NVA co-support body was confirmed. In addition, as shown in FIG. 3, there was a tendency that the point at which the light transmittance changed was lower as the weight ratio of NVIB was larger.

C Evaluation of dew condensation prevention characteristics

As in Example 1, a dew condensation prevention confirmation experiment and a recovery experiment were performed. However, a temperature condition of 50 ° C. was used in the recovery experiment. As a result, it was confirmed that all the samples sufficiently absorbed dew condensation water, exhibited excellent dew condensation prevention properties, had excellent water release at high temperatures, and exhibited reproducibility with good reproducibility.

(Examples 5 and 6)

Preparation of crosslinked products of A NV I B polymer and NV I B-NVA co-base

From the NV IB monomer (100 parts by weight) and the crosslinking agent N, N-methylenebisacrylamide (BisA) (5 parts by weight) prepared in Example 1, azobisisobutyro was used as a polymerization initiator. Using nitrile (AIBN), a cross-linked body of the NV IB stack was solution-polymerized (Example 5).

Similarly, NV IB monomer (80 parts by weight) synthesized in Example 1, NVA monomer (20 parts by weight) synthesized in Example 2, and N.N-methylenebisacrylamide (B is A) (5% by weight), a solution of a crosslinked product of NVIB-NVA copolymer was prepared using azopisoisobutyronitrile (AIBN) as a polymerization initiator (Example 6).

Characterization of crosslinked products of B NV I B polymer and NV I B-NV A copolymer

A heat sensitivity test was conducted in the same manner as in Example 1 to confirm the heat sensitivity of the crosslinked polymer of each of the NV IB stack and the NV IB-NVA copolymer. However, in this example, the heat sensitivity was confirmed by elevating the temperature in the oven by 5 ° C. and examining the gel expansion degree (fold) and the volume change.

As shown in FIG. 4, in particular, the crosslinked product of the NVIB-NVA copolymer (80/20 parts by weight) has a large change in water absorption around 50 ° C., resulting in heat sensitivity. You can see that.

C Evaluation of dew condensation prevention characteristics

As in Example 1, a dew condensation prevention confirmation experiment and a recovery experiment were performed. However, the crosslinked polymer of the NVIB polymer and the NVIB_NVA copolymer is coated by a printing method to prevent dew condensation (100 parts by weight of the breathable base material, 50 parts by weight of the crosslinked body). I got In the recovery experiment, a temperature condition of 50 ° C was used.

As a result, it was confirmed that all the samples sufficiently absorbed the dew condensation water, exhibited excellent dew condensation prevention properties, had excellent water release at high temperatures, and exhibited reproducibility with good reproducibility. Industrial applicability

According to the present invention, water can be absorbed in the range of 5 to several hundred times, and excellent dew condensation prevention effect is obtained.Even if water is absorbed, water is released when the temperature rises, and long-term use is possible. It has become possible to provide a dew condensation preventing material that is highly durable and durable.

In addition, such anti-condensation material can be provided as a composite material with a wallpaper or a breathable base material, and can provide a material that has improved handleability and functionality and that effectively prevents dew condensation on the inner wall of a building or the like. became.

Furthermore, it has become possible to provide an anti-condensation material exhibiting excellent moisture absorption / desorption characteristics and good reproducibility.

Claims

The scope of the claims

1. An anti-condensation material characterized by using a heat-sensitive super-absorbent polymer as a main component of the anti-condensation material, which reversibly absorbs and releases moisture as the temperature changes.

2. The anti-condensation material according to claim 1, wherein the heat-sensitive superabsorbent polymer is used in combination with a gas-permeable base material.

3. The condensation according to claim 1, wherein the heat-sensitive superabsorbent polymer is a polymer containing N-vinylacylamide as a monomer component or a derivative thereof as a main component. Prevention material.

4. The heat-sensitive superabsorbent polymer is mainly composed of poly (N-vinylisobutylamide) or a copolymer of N-vinylisobutylamide and N-vinylacetamide. The dew condensation preventing material according to any one of claims 1 to 3, which is characterized by the following.

5. The dew condensation preventing material according to any one of claims 1 to 4, wherein the heat-sensitive superabsorbent polymer is cross-linked using a divinylated platform.

6. The divinylated product is a member of the group consisting of N.N-methylenebisacrylamide, N, N-methylene-bis-N-vinylacetamide, N, N-butylene-bis-N-vinylacetamide and derivatives thereof. 6. The anti-condensation material according to claim 5, wherein at least one of them is used.

7. The heat-sensitive superabsorbent polymer, 100 to 500 parts by weight of the air-permeable base material, 100 to 500 parts by weight of a plurality of units, characterized in that the multiple units The dew condensation preventing material according to any one of the above items.