JPH0611431B2 - Humidity control method for buildings - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of controlling humidity in a building, and more particularly to a method of controlling humidity using polyurethane foam.

(Conventional technology) With the progress of construction technology, the traditional Japanese construction method using wood as the main material has been changed to the construction method using inorganic materials such as iron and concrete as structural materials. As for interior materials, materials such as tatami mats and other natural fibers have decreased, and synthetic resins and synthetic fibers have come to be used frequently.

(Problems to be solved by the invention) As a result, the ability to absorb and release moisture, which is a major feature of wood and other natural fibers, can no longer be expected, and homes suffer from discomfort due to high humidity during the rainy season. When it is necessary, it becomes an excessively dry state and various problems occur. In addition, the increase and decrease of humidity due to climate change is great in warehouses, which is an obstacle to stored items.

In order to remove the effect of such humidity changes, the dehumidifier is operated during the rainy season and the humidifier during dry season, but a lot of energy is required and maintenance is troublesome.

(Means for Solving Problems) The present inventors have a method of using recent building materials, which has a moisture control action similar to that of natural fibers such as wood and can save energy without requiring complicated management. As a result of the investigation, the inventors have found that hydrophilic polyurethane foam is effective and arrived at the present invention.

That is, in the present invention, a prepolymer obtained by reacting a polyoxyalkylene polyol (a) having a hydroxyl value of 20 to 80 mgKOH / g containing at least 50% by weight or more of oxyethylene groups with diphenylmethane diisocyanate (b) is mixed with water. However, it is a method for controlling the humidity of a building, which comprises spraying and foaming the building.

Examples of the polyoxyalkylene polyol used in the present invention include polyhydric alcohols such as ethylene glycol, propylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1,3,6-hexanetriol, and pentaerythritol. It is an addition polymerization product of oxide or ethylene oxide and propylene oxide. Further, polymer polyols obtained by polymerizing olefins such as acrylonitrile and styrene in these polyoxyalkylene polyols can also be used.

In addition to the above, polyester polyols obtained by reacting higher fatty acid ester polyols and polycarboxylic acids with low molecular weight polyols, and OH of castor oil, dehydrated castor oil, etc.
Group-containing higher fatty acid esters can also be used. The oxyethylene group content in the polyoxyalkylene polyol is 50.
~ 90 wt% is suitable. Below this range, the hydrophilicity is low and the humidity control function of the foam is deteriorated. A hydroxyl value of 20 to 80 mgKOH / g is suitable. Above this, the number of closed cells increases in the foam and the contact area with the air decreases, so the humidity control function of the foam deteriorates.

4,4 'as diphenylmethane diisocyanate
Isomers, 2,4 'isomers, 2,2' isomers and mixtures thereof, as well as methylene bridged polyphenyl polyisocyanates known as crude diphenylmethane diisocyanates.

Further, dimers, trimers, carbodiimide-modified products of these isocyanates can also be used. When the prepolymer is produced, the reaction amount of the polyoxyalkylene polyol and diphenylmethane diisocyanate is adjusted so that the isocyanate group content of the produced prepolymer is in the range of 5 to 20% by weight.

When performing blowing foaming, it is not necessary to strictly define the mixing ratio of the prepolymer and water as in ordinary urethane foam blowing, and therefore the blowing operation can be performed extremely easily. The mixing ratio is 10 to 100 parts of water based on 100 parts by weight of the prepolymer.
Use parts by weight. If the amount of water exceeds this range, the stock solution will flow and a sprayed product of the desired thickness cannot be obtained. If it is less than this range, the foaming is incomplete and the sprayed product cannot be used.

A foam stabilizer may be used if necessary in order to improve the dispersibility of the prepolymer and water during mixing. As the foam stabilizer, an organic silicon surfactant used in ordinary foaming of urethane foam can be used. If necessary, a catalyst may be used during foaming. As the catalyst, a tertiary amine catalyst and / or an organometallic catalyst usually used for urethane foaming are used. To reduce the viscosity of other prepolymers, it is possible to use plasticizers and solvents, and for example, it is also possible to mix fillers such as calcium carbonate, silica and glass fibers, and to mix colorants and stabilizers. You can also

The sprayed raw material mixture foams in 5 to 10 seconds, and when left as it is at room temperature, it is cured to become a hydrophilic polyurethane foam.

The physical properties of the foam produced are: density 20-130kg / m ³ , tensile strength 1.0-5.0kg / cm ² , elongation 100-400%, tear strength 0.5-
It is 2.0 kg / cm, and has a significantly higher water absorption than ordinary urethane foam.

When spraying urethane foam, a low pressure spray device,
Any high pressure spraying device can be used.

When constructing on the inner surface of a building, spray it on the walls and ceiling so that the thickness after foaming is 5 to 20 mm. After spraying on the wall surface and before curing the foam, plywood, wallpaper and other interior materials can be attached as a pouch and adhered as they are. Similarly, it is also possible to adhere the carpet after spraying it on the floor surface.

When sprayed on the outer surface of the building, the outer surface of the building is covered with an exterior material so that the urethane foam constitutes the intermediate layer. Alternatively, the hydrophilic foam of the present invention may be sprayed and foamed, and then hydrophobic urethane or other synthetic resin may be sprayed to form a waterproof / protective layer.

(Operation and effect) Since the hydrophilic foam of the present invention thus constructed absorbs or releases water depending on the relative humidity of the atmosphere, the humidity in the room can be automatically adjusted, and the humidification and dehumidification can be performed. There is no need to operate the device. In addition, since the hydrophilic urethane foam has air bubbles communicating with each other, the air in the room can easily penetrate into the foam, so that moisture can be absorbed and released efficiently. Further, since this hydrophilic polyurethane foam has elasticity, it is also a great feature that the surface of the interior material can be prevented from being damaged when the article collides with it.

(Examples) Examples of the present invention will be described below.

Example 1 2500 parts of polyoxyalkylene triol containing 70% of oxyethylene group and 30% by weight of oxypropylene group using glycerin as an initiator and 1963 parts of crude diphenylmethane diisocyanate were reacted at 55 to 60 ° C. for 4 hours to give an NCO group content of 12 A weight percent prepolymer was prepared.

Using a high-pressure spray foaming machine from Toho Machine Industry Co., Ltd., the weight mixing ratio of 80 wt% methylene chloride solution of this prepolymer and water was set to 100: 60 and sprayed on the ceiling and wall of one room of a concrete house. A 10 mm hydrophilic polyurethane foam layer was formed.

Hygrometers were installed in the room where the spraying was performed and the room where it was not performed, and the humidity on a rainy day was measured. The humidity of the constructed room was 60%, but the humidity of the unconstructed room was 86%.

Example 2 80 parts by weight of polyoxyalkylene diol containing 80% by weight of oxyethylene group and 20% by weight of oxypropylene group with ethylene glycol as an initiator and 75% by weight of oxyethylene group and 25% by weight of oxypropylene group with glycerin as an initiator A mixture of 20 parts by weight of polyoxyalkylene triol containing was reacted with crude diphenylmethane diisocyanate to produce a prepolymer having an isocyanate group content of 10% by weight.

Using a Randsburg high-pressure spray foaming machine, 100 parts by weight of a 80% methylene chloride solution of this prepolymer, 64 parts by weight of water,
A mixture of 4 parts by weight of a foam stabilizer SH-190 (organic silicon surfactant manufactured by Toray Silicone Co., Ltd.) was sprayed. Construction is frontage
It was sprayed on the ceiling and both side walls of one room of a concrete house with 3.6 m, depth of 3.6 m, and height of 2.4 m. The raw material mixture finishes foaming in 1 minute, and is left at room temperature overnight as it is.
A 15 mm hydrophilic urethane foam layer was formed. The density of the foam was 1.05 kg / m ³ .

A thermometer and a hygrometer were installed in the room where the spraying was performed and the room where the spraying was not performed. When the temperature and humidity of the non-constructed room were 25 ° C and 90%, the temperature and humidity of the constructed room were 25 ° C and 60%.

Claims (1)

[Claims] 1. A prepolymer obtained by reacting a polyoxyalkylene polyol (a) having a hydroxyl value of 20 to 80 mgKOH / g containing at least 50% by weight or more oxyethylene groups with diphenylmethane diisocyanate (b) with water. A method for controlling the humidity of a building, which comprises mixing and blowing and foaming the building.