JPS6133944B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved method for insulating houses, etc. using the urea-formaldehyde resin foam (hereinafter abbreviated as "UF foam"), and particularly relates to an improved method for reducing formaldehyde odor. UF foam has been attracting attention in recent years as a residential insulation material in the energy-saving era because it is inexpensive, combustible, and can be foamed on-site. UF foam is usually constructed using an on-site foaming method, but formaldehyde is released during the drying process of the foam after construction, and its toxicity to the human body has become a problem. Although the amount of formaldehyde generated above can be suppressed to some extent by changing the formulation of the UF foam or the foaming conditions, the suppression effect is still insufficient with this method. The present inventors have discovered that in the insulation construction method for houses, etc.
Various methods have been studied to reduce the amount of free formaldehyde released indoors, but when a material with low moisture permeability such as PVC cloth is used as an interior surface finishing material, the release We learned that almost no formaldehyde is emitted, whereas in the case of fiber-finished walls, almost all of the formaldehyde generated is emitted into the room. Therefore, as a result of intensive study on improving the insulation method to reduce the formaldehyde emitted indoors when finishing fiber walls, we found that by incorporating a synthetic resin emulsion into the fiber wall material, we were able to improve the construction of fiber walls. Since a synthetic resin film is formed afterwards, formaldehyde, which is generated over a long period of time after the UF foam is installed and is dried, can be prevented from being released indoors. The present invention was completed by discovering that the concentration of free formaldehyde can be significantly reduced. That is, the present invention is a method for insulating houses, etc. using UF foam, which is characterized in that the inner walls are finished with fiber walls, and the fiber wall material contains a synthetic resin emulsion. The insulation method using UF foam is carried out as follows. Using an aqueous solution of urea/formaldehyde initial condensate (hereinafter referred to as "resin liquid") and a curing liquid as raw materials, air is first added using a foaming gun for UF foam commercially available from Schiaum Chemie in West Germany and BIP in the UK. The hardening liquid is foamed by blowing into it.
A wet UF foam obtained by spraying and mixing a resin liquid from a spray nozzle is injected or sprayed into the space to be insulated. After construction, the foam is usually left to harden and dry. For example, the resin liquid is manufactured in the following manner. Add water to urea and formalin as needed, and react at 80 to 95°C near neutrality. Once the reaction has progressed to a certain extent, the pH is adjusted to continue the reaction, and at the end of the reaction, a small amount of urea is added to reduce unreacted formaldehyde. Dilute with water as necessary to adjust solids content. In addition,
Modified products in which part of the urea is replaced with phenol, melamine, etc. can also be used. As the curing liquid, an aqueous solution containing a curing agent, a foaming agent, and an auxiliary agent is used. Examples of curing agents include acidic substances such as phosphoric acid, sulfuric acid, acetic acid, and P-toluenesulfonic acid; examples of blowing agents include alkylaryl sulfonates, higher alcohols, sulfuric ester salts,
Examples of auxiliary agents include polyethylene glycol, polypropylene glycol, polyvinyl alcohol, etc. as hydrophilicity imparting agents, and salts such as calcium and magnesium as water quality conditioners. Materials used for interior walls include gypsum board, wood wool cement board, pulp cement board, asbestos slate, asbestos silica board, wood, plywood, fiberboard, particle board, gypsum plaster, plaster, mortar, etc. . As the fibrous material, various grades of commercially available products are used, and there are those whose main components are cotton fibers, filamentous fibers, and organic granules, and those which contain organic substances and other inorganic substances. Fiber wall materials are usually installed using troweling or spraying methods. Synthetic resin emulsions that can be incorporated into fiber wall materials include SBR latex, NR latex, and CR.
Latex, synthetic rubber latex such as NBR latex and MBR latex, vinyl acetate copolymer emulsion, polyvinyl chloride emulsion, acrylic ester copolymer emulsion, polybutylene emulsion, polyepoxide emulsion, polyurethane emulsion and other known materials. are used alone or in combination of two or more. The amount of synthetic resin emulsion to be added must be such that a film of the synthetic resin can be formed after the fiber wall is constructed. Normally, a solid content of about 5 to 50% by weight relative to the fiber wall material is appropriate. There are two methods of installing UF foam: injection method and spraying method. For example, the injection method is a method used for wall insulation renovation work in existing homes. A hole is drilled into a hollow wall from the inside wall of the home, and wet UF foam continuously released from a foaming gun is press-fitted into the hole. This is a way to block the problem. The spraying method is also called the cheesecloth construction method, and is a method used, for example, in the wall insulation work of newly built homes, and involves spraying wet UF foam from a foaming gun onto the space covered with cheesecloth. The order of the construction of the fiber wall material and the construction of the UF foam may be whichever comes first, and there is no particular restriction on the time for leaving the material after construction. The heat insulation method of the present invention is particularly useful for heat insulating homes, but it can also be used for buildings other than homes such as factories, buildings, hospitals, schools, shops, and various warehouses. In residential applications, it is suitable for thermal renovation work on existing homes and insulation work on newly built homes, but it is particularly suitable for insulation renovation work on existing homes. In addition to walls, it can also be used to insulate areas such as ceilings, attics, and under floors. According to the method of the present invention, the amount of formaldehyde generated over time after insulation construction can be significantly reduced without changing the formulation of the UF foam itself, the construction method, etc., and the concentration is low enough to not cause harm to the human body. This has an extremely significant effect on the improvement of insulation construction methods for houses, etc. using UF foam. The present invention will be explained below using examples. "Parts" in the examples represent "parts by weight." Example 1 An 8-tatami-sized one-room house with windows measuring 1.73 m x 1.15 m on both north and south sides was used as an experimental house.
Ceiling height 2.4m from floor, wall area approximately 30m ² , interior volume approximately 30m ² , large wall structure (hollow thickness 105mm). Tatami floor,
Interior 9mm gypsum board, exterior cement mortar,
Decorative gypsum board for ceiling, 100mm thick glass wool. The resin liquid and curing liquid of UF foam were prepared as follows. Preparation of resin liquid: 36.7 parts of urea, 75.4 parts of 37% formalin, 30 parts of water, and 0.3 part of 24% aqueous ammonia were reacted at around 90° C. for 30 minutes to 1 hour while stirring and mixing. 40
% formic acid was added to adjust the pH to 4 to 5, and after further reaction for 1 hour, the pH was adjusted to 8 with 20% caustic soda. After adding 4.2 parts of urea and reacting at 65° C. for 30 minutes, the resulting reaction product was immediately cooled and diluted with the same volume of water to obtain a resin liquid. Preparation of hardening liquid: After stirring and mixing 13.4 parts of 85% phosphoric acid, 8.3 parts of sodium branched dodecylbenzenesulfonate, and 3.2 parts of a stabilizer, the mixture was diluted with water to a volume ratio of 10 to obtain a hardening liquid. 60 cm in length and width on the interior plaster board of the above experimental house.
UF foam injection holes with a diameter of 18 mm were drilled at intervals. Next, the above resin liquid and curing liquid were loaded into the tank of a foaming machine and introduced into a foaming gun for UF foam commercially available from BIP in the UK at a volume ratio of 1:1, and at the same time air was blown into the foaming gun. It was injected through a flexible nozzle connected to the Resin liquid and curing liquid flow rate each 2.5/min, liquid temperature 22 to 29°C, foaming gun back pressure 3.2 Kg/cm ² G. After filling the injection hole with water-based putty using a metal spatula, the non-volatile content of 50% is applied to a commercially available fiber wall material (trade name "Urabune").
A material prepared by mixing SBR latex in an amount of 20% by weight was applied with a metal trowel at a rate of 220 g per 1 m ² of plasterboard. Stored in the center of the room for a month (temperature 6-14℃)
The results of measuring the formaldehyde concentration over the period are as follows, and the value was extremely small. Moreover, almost no odor was detected. Formaldehyde concentration was measured by spectrophotometry using acetylacetone (detection limit 0.1 ppm).

[Table] By the way, the environmentally acceptable concentration of formaldehyde is
It is 2ppm. Example 2 The same procedure as in Example 1 was carried out except that the amount of SBR latex with a non-volatile content of 50% was changed from 20% to 40%, and the following results were obtained. In addition, there was almost no odor.

[Table] Example 3 In Example 1, instead of the SBR latex with a non-volatile content of 50%, an acrylic emulsion mainly composed of butyl acrylate with a non-volatile content of 45% was used at a weight ratio of 25%.
The process was carried out in exactly the same manner except that the mixed materials were used.
I got the following results. Moreover, there was almost no odor.

[Table] In addition, NR latex, CR latex, NBR latex, MBR latex, vinyl acetate copolymer emulsion, polyvinyl chloride emulsion, and polybutylene emulsion in fiber wall materials were tested using the same test method as in Examples 1 and 2. , polyepoxide emulsion, polyurethane emulsion, etc. were applied and tested, and almost the same results as Examples 1 to 3 were obtained. Comparative Example Example 1 was carried out in exactly the same manner as in Example 1, except that the mixing of SBR latex into the fiber wall material was omitted. The results were as follows: The odor was significant.

【table】

Claims (1)

[Claims] 1. A method for insulating houses, etc. using urea-formaldehyde resin foam, characterized in that the inner walls are finished with fiber walls and a synthetic resin emulsion is contained in the fiber wall material.