JP2003003003A - Insect-controlling polystyrene foam insulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polystyrene foam insulator in which a chemical effective for control of insects or the like but safe for men and beasts is dispersed with concentration uniform and effective to the inside, and the chemical effects can be permanently preserved. SOLUTION: A sodium borate aqueous solution is thermoregulated to an enough temperature to cause at least partial prefoaming of polystyrene beads at the following process. At least partial prefoaming of the polystyrene beads is caused by fluidly introducing the beads into a vessel while the thermoregulated sodium borate aqueous solution is sprayed. Water content is removed from the prefoamed polystyrene beads by evaporation, and sodium borate is solidly stuck to the minutely uneven surface of the plystyrene beads. The complete foaming is established by introducing the sodium borate-carried and prefoamed polystyrene beads into the mold and by heating it. A foamed polystyrene block is molded with making the surface tacky and integratedly fusing it by small pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulating material based on expanded polystyrene, and particularly to a biocidal activity against insects, molds, fungi, etc. by a drug which does not adversely affect the human body and the environment.
In particular, the present invention relates to a method for producing an insect control expanded polystyrene heat insulating material which is endowed with termite control properties and which can effectively retain its biocidal properties for a long period of time.

[0002]

2. Description of the Related Art It is possible that wood and other wood-based structures are attacked by termites, ordinary ants, and other harmful insects, and in extreme cases even the risk of building collapse. well known. Research has been conducted to protect against such harmful insects. In addition, recently used building insulation materials protect these harmful insects from severe external climatic conditions, especially cold temperatures, and provide a convenient environment for the activity and reproduction of harmful insects throughout the year. It is also known to exist.

Accordingly, chemicals have been developed for external coating of buildings or foundations to prevent the ingress of harmful insects into buildings, many of which are human or otherwise. Most of them are banned because they pose a danger to pets such as dogs and cats.

[0004] For example, creosote has been used for preserving and preserving wood for a long time, but it cannot be used for housing because it has been certified as a carcinogen. Also, a solution of chromium copper arsenate (CCA) is used in the process of infiltrating it into wood under high pressure, but its insecticidal and fungicidal properties are very strong, and its handling requires special strict care. And

US Pat. No. 2,186,134 (Chapman) describes a preservative composition comprising an aqueous solution of a halogenated phenol and an alkali metal borate salt, such as fiberboard, paper insulation and the like. Application to quality building materials is disclosed.

Recently, expanded polystyrene has been widely used as a heat insulating material for buildings. For example, a core material of expanded polystyrene (hereinafter, may be abbreviated as “EPS”) is sandwich-bonded between two skin layers (for example, a wooden board, a metal plate, etc.) with an appropriate adhesive. Used as a composite structure panel. The thickness of the EPS core material is usually several cm to several tens cm. Examples of the wood-based skin layer include hard boards, particle boards, chip boards, oriented strand boards, and plywood. To make the panel a bearing wall, the thickness of each wood skin layer would be on the order of 1 cm. In some cases, the skin layer may be bonded to only one side and used as a heat insulating material. The size of these insulation panels may be of any convenient size, for example 4 x 8 feet (about 1.2
X 2.4 m) or about 1 x 2 m. EPS insulation panels exhibit high insulation performance. Eliminate drafts through building roofs, walls, and floors.

However, EPS insulation panels are often susceptible to insects (eg termites), molds and fungi. For example, a termite makes a food passage hole in a wood-based skin layer and further penetrates to the inside of the EPS core layer to invade and form a nest therein. As described above, the environment inside the EPS insulation panel core layer is shielded from extreme heat during the summer and from the cold during the winter, and is non-toxic. Therefore, it is suitable for constant growth and proliferation. The application of conventional drugs has various problems as described above. Furthermore, EPS
Is hydrophobic (non-hydrophilic), it is difficult to firmly attach a drug in the form of an aqueous solution to EPS foam by a spraying method or a dipping method. There is a problem that it is difficult to distribute the medicine, and even if the medicine adheres to the surface portion to some extent, it easily falls off, and further it is difficult to remove water that has penetrated into the inside and dry it.

[0008]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an EPS insulating material with a drug effective for controlling insects, etc. but safe for humans and animals to the inside. It is an object of the present invention to provide a method capable of efficiently, easily and cost-effectively producing an EPS insulating material which can be uniformly distributed in an effective concentration and can retain its drug effect substantially permanently.

Other objects, advantages and features of the invention will be apparent from the further description below.

[0010]

Thus, the present invention provides: (a) preparing a hot aqueous solution of biocidal sodium borate, the temperature of which is at least when contacted with polystyrene beads in the next step (b). Adjusting to a temperature sufficient to cause partial pre-expansion of the polystyrene beads; (b) fluidizing the polystyrene beads into the container,
The polystyrene bead stream is spray sprayed with the hot, temperature-adjusted aqueous sodium borate solution to at least partially pre-expand the polystyrene beads; (c) treated with an aqueous sodium borate solution and at least partially pre-expanded. The polystyrene beads thus prepared are then sent to another air-permeable container to substantially evaporate and remove moisture by ventilation and / or heating, and at the moisture removal temperature, pre-expansion of polystyrene beads is promoted to be completed and pre-expanded. Sodium borate is adhered to the surface of the polystyrene beads showing finer irregularities in a solid state; (d) Sodium borate-supported pre-expanded polystyrene beads from step (c) are stored; (e) Sodium borate-supported pre-expanded polystyrene beads are stored. Introduce into the mold, heat with steam, and polish (1) Forming a single expanded polystyrene block by making the len beads complete foaming and making their surfaces tacky, and also fused together by slight pressure; (f) cooling the molded block. Solidifying; and a method for producing a polystyrene foam heat insulating material, comprising:

Suitable borates for the purposes of the present invention include sodium metaborate (NaBO ₂ ), sodium tetraborate (Na ₂ B ₄ O ₇ ), sodium pentaborate (Na ₂ B ₅ O ₈ ),
Sodium hexaborate (Na ₂ B ₆ O ₁₀ ), sodium octaborate (Na ₂ B ₈ O ₁₃ ), sodium diborate (Na ₄ B
₂ O ₅ ), and hydrates thereof, as well as those selected from the group consisting of mixtures thereof. Also included in the definition of borate is a borate ester that exhibits an action equivalent to that described above. Borate can noteworthy as appropriate for the particular invention among these are chemical analysis composition, sodium oxide (Na ₂ O) 14.7%; boron oxide (B ₂
O ₃₎ 67.1%; a crystal water (H ₂ O) eight sodium borate tetrahydrate is _{18.2% (Na 2 B 8 O} 13 · 4H 2 O), of this compound piercing insects It has the effect of preventing many substances, and exhibits appropriate solubility under the temperature conditions adopted in the present invention.

The aqueous sodium borate solution used in the present invention has a solubility of sodium borate, a sodium borate concentration required in the final expanded polystyrene insulation (eg, at least 250 by weight polystyrene).
0 ppm, preferably 3000-6000 ppm), and considering factors such as pre-expansion of polystyrene in the next step, etc., below the boiling point of water, eg 50-90 ° C, preferably 55-70 ° C, typically 60 It is around ℃. The sodium borate aqueous solution is preferably stirred well so that no solid content remains.

In the method of the present invention, polystyrene beads are generally adhered with an aqueous sodium borate solution and pre-expanded almost at the same time (beads are expanded to rice grains or wheat grains), and therefore, generally, It is supplied to the vicinity of the top of a vertical cylindrical container through a hopper. The warm or hot aqueous sodium borate solution is sprayed onto the polystyrene beads flowing in the cylindrical container. Depending on the temperature of the aqueous solution (eg, 60 ° C.), the polystyrene bead particles undergo pre-expansion (but not complete expansion), at least in part, and preferably entirely, causing wrinkles, or even wrinkles on the surface of each particle. To develop fine irregularities (craters). By generating such wrinkles or fine irregularities on the bead surface, the aqueous solution of sodium borate can be favorably held on each bead surface.

Since the polystyrene beads thus pre-expanded and having a large amount of sodium borate aqueous solution on the surface are in a wet state, they are then sent to a dryer, where the pre-expanded polystyrene beads are blown and / or heated to remove them. Water is substantially evaporated off and pre-expansion of the non-pre-expanded beads is completed, and sodium borate is attached in a solid state to the surface of the polystyrene beads having fine irregularities by the pre-expansion. This phenomenon is an important feature that characterizes the present invention.

Next, the sodium borate-supported and dried pre-expanded polystyrene beads are temporarily stored in a storage tank. This storage is preferable because sodium borate is attached to the fine irregularities of the polystyrene beads in a more stable and firm state within the storage time.

Finally, from this storage tank, sodium borate-supported and dried pre-expanded polystyrene beads were introduced into a mold for molding and heated by steam,
While fully expanding the pre-expanded polystyrene beads,
The surfaces are made tacky, and are also fused together by slight pressure to form a block.
Then it is cooled, solidified and removed from the mould. The molding size is arbitrary, but for example, 4 feet in height (about 1.2
m), width 8 feet (about 2.4 m), thickness 5 inches (about 0.127 m), and larger molding size can be used, if necessary, slicing or other cutting of the molding A heat insulating material having a desired size can be obtained by processing.

In the method of the present invention, since pre-expanded polystyrene beads carrying sodium borate on each surface portion are supplied to the molding process, the sodium borate migrates deeply from the surface portion of the beads to the inside of the beads during molding. Instead they remain on or near the surface of the individual beads. Therefore, when observing the cross section of the molded product on an enlarged scale, sodium borate is deposited in a layered form or a substantially continuous film form near the fusion boundary surface (grain boundary) of each EPS in any part of the cross section. It is observed that it exists. Therefore, sodium borate is present in the same concentration distribution on average from the surface to the inside or the center of the molded product. That is, sodium borate is not unevenly distributed only on the surface portion or near the surface. Therefore, even if a block molding product having a large size (for example, a large thickness) is manufactured by the method of the present invention and sliced into an appropriate thickness suitable for the purpose of use as a heat insulating material, the slice heat insulating material is Any part of the whole
The same sodium borate concentration distribution (and therefore the same efficacy) will be exhibited.

The distribution state of sodium borate in the EPS block-molded product can be known by the following test method. An alcoholic solution of curcumin (eg 10%), which acts as an extractant, is atomized into a fine mist and sprayed onto the surface or cut surface of the block and dried. Then, a solution prepared by dissolving 6.0 g of salicylic acid in 20 ml of concentrated hydrochloric acid was diluted with ethanol to 100 ml, sprayed finely onto the surface in the same manner and left for several minutes to observe discoloration. Where red color is seen, it indicates the presence of sodium borate. This test method can also be used for quantitative analysis (for example, colorimetric absorption spectrometry) by modifying the procedure. According to this test method, the surface of the EPS block molded product manufactured by the method of the present invention or a cross section at an arbitrary position is almost circular (as viewed in cross section).
A deep red color appears in the form of a layer or a thin film along or around the outer peripheral edge (fusion grain boundary) of each EPS (when viewed as a whole, in a repeating annular pattern corresponding to each EPS). , It was found to extend uniformly over the entire surface and cross section of the EPS block molded product. The reason for this uniform distribution is that the pre-expansion of polystyrene beads in step (b) of the method of the present invention causes countless minute irregularities or wrinkles (or craters) on the surface of each bead, and into them, The spray-supplied sodium borate aqueous solution is retained, and in the subsequent drying step (c) and storage step (d), solid (powder) form of sodium borate is deposited between the wrinkles (craters) to further strengthen and In the foam-molding step (e), the beads are further fully foamed to become fully foamed, become sticky on the surface, and are taken into the melted portion of the EPS, which have been stably fused, and are integrated with each other. It is believed to be held embedded in the surface area of the foam.

As described above, in the EPS block molded product according to the method of the present invention, sodium borate is firmly held in a state of being embedded in the EPS fusion-solidified region (grain boundary), so that it can be easily detached. Without doing so, you will stay there forever. Therefore, it will last forever without compromising its efficacy. Further, as described above, since sodium borate is distributed throughout the heat insulating material, even if the surface portion of the heat insulating material is damaged, pests etc. will invade from the damaged portion toward the inside of the heat insulating material. , Or nesting or inhabiting is effectively prevented. On the other hand, by the conventional dipping method or spraying method,
When the chemical solution is applied to the EPS block, it is difficult for the chemical solution to penetrate into the inside of the block due to the strong hydrophobicity of polystyrene, and the chemical is weakly adhered to the surface of the block and its vicinity and easily distributed. It was difficult to distribute the drug to the center of the block. Therefore, when the surface portion of the heat insulating material produced by such a chemical application method according to the conventional method is damaged, pests or the like enter from the portion,
there is a possibility.

The EPS heat insulating material produced by the method of the present invention can be used as a building outer peripheral wall heat insulating material, an inner wall heat insulating material, a floor heat insulating material, a base heat insulating material, a slab under heat insulating material, and the like. Those having properties such as dimensions, density, heat insulation performance, compression resistance, etc., which are compatible with the above can be designed as desired.

The EPS insulation material according to the present invention can be used as it is or after being processed into a composite structure panel. The composite structure panel includes, for example, a metal plate, a plastic plate, and a wood-based plate having a skin layer.
The heat insulating material layer may be used as a core and a skin layer may be laminated and bonded to one or both surfaces of the core with an adhesive, for example. As the wood-based board skin layer, for example, hard board, particle board, chip board, oriented strand board,
There are plywood, etc.

[0022]

EXAMPLES The present invention will be described below with reference to examples, but it is clear that the present invention is not intended to limit the present invention and is intended only to facilitate understanding of the present invention.

[0023] Example 1 eight borate disodium tetrahydrate _{(Na 2 B 8 O 13 ·} 4H
₂ O) (1.0 kg) was added to hot water (3.6 liters) at 68 ° C., and the mixture was thoroughly stirred to completely dissolve it. Polystyrene beads were placed in a hopper, and dropped and fed at a rate of 250 kg / hour from an inlet near the top of the vertical cylindrical mixing container, and the sodium borate aqueous solution (about 6
(0 + 5 ° C) was sprayed at a rate of 77 ml / min.
Most of the beads discharged from the bottom of the mixing container were pre-expanded to the extent of rice grains, and the surface was wet with the sodium borate solution. The pre-expanded beads treated in this manner are ventilated, introduced into a warm dryer and dried, and solid (powdered) sodium borate enters, deposits and is retained in the fine craters on the surface of the dried beads. Is recognized as
The beads that had not been pre-expanded in the previous mixer also completed pre-expansion. The dried sodium borate-supported pre-expanded beads were stored in a storage tank for half a day and allowed to undergo conditioning.

Steam heated mold (internal dimensions 4 ft x 8 ft x 5 in; 1.2 mx 2.4 mx
0.127 m), carrying sodium borate from the above storage tank,
Pre-expanded polystyrene beads were charged to cause complete expansion of the beads, and their surfaces were made tacky by heat to fuse the fully expanded beads together to form a block. Thereafter, cooling water was caused to flow through the outer wall of the mold to sufficiently solidify the block-shaped molded product, and the block-shaped molded product was taken out from the mold. When the distribution state of sodium borate on the surface and the cut surface of the sample cut out from the EPS molded product was examined by a test method using the curcumin-containing extract and the ethanolic salicylic acid acid solution color former, It was observed that the entire surface (from the surface portion to the central portion of the block) was deposited as a layer or a thin film embedded in the EPS fusion grain boundary. Further, the sodium borate content analyzed by the colorimetric absorption spectrometry for the above-mentioned quantitative analysis of sodium borate was determined to be 4468 ppm based on the weight of the EPS molded product.

Example 2 (Termite termite protection test) From the EPS molded article obtained in Example 1, a length of 6 inches (15c)
m), width 6 inches (15 cm), thickness 4.5 inches (1
A sample (1.5 cm) was cut out (Sample I).
As a comparative control, a sample of EPS having the same size containing no sodium borate was used (control). The termites used in the test are generally Eastern underground termites (eastern).
Subretranean termites called Reticulitermus flavipes collar (Ret)
iculterms flavipes Kolla
It was collected from a colony of a wild pine tree trunk of r), which grows naturally.

Approximately 5.6 wet sand / vermiculite mixture as a medium for termites in a 5 gallon (18.6 L) metal can.
kg (water 1.67kg, vermiculite 0.363k
g and 3.58 kg of sand; the volume ratio of vermiculite to sand was 1: 1) and heat-sterilized brick was placed at the end as an EPS sample support. Thereafter, 1.0 g of termites (the number of surviving termites = about 690) was released onto the above medium, and then the sample I was covered thereon with one edge of a brick support. We regularly observed the habitation of termites. The activity of termites gradually slowed down, the number of corpses increased in a few days, and one week later, all termites were dead.

The control was tested using the same equipment and operation as above, with no change in activity after one week, and at the edges of the untreated EPS sample in contact with the wet sand / vermiculite mixture medium. Several holes were made by termites.

Example 3 (water immersion test: chemical retention) The EPS molded article obtained in Example 1 obtained in Example 1 was 3 inches in length (7.5 cm), 3 inches in width (7.5 cm), and thick. A 2 inch (5 cm) sample was cut out. A weight was attached to this, immersed in water at 25 ° C. for 1 week, taken out, dried and cut, and the state of leaching loss of sodium borate was inspected by the above color development test method on the cut surface that appeared. However, although the color of red was slightly weaker near the outer surface that was in contact with water during immersion, it showed exactly the same color development state as the unimpregnated comparative control sample from immediately below the outer surface of the sample to the inside. It was

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Claims (10)

[Claims] 1. When (a) a hot aqueous solution of biocidal sodium borate is prepared and the temperature of the aqueous sodium borate solution is brought into contact with polystyrene beads in the next step (b), at least partial pre-expansion of polystyrene beads occurs. (B) while introducing polystyrene beads into the container by fluidization,
The polystyrene bead stream is spray sprayed with the hot, temperature-adjusted aqueous sodium borate solution to at least partially pre-expand the polystyrene beads; (c) treated with an aqueous sodium borate solution and at least partially pre-expanded. The polystyrene beads thus prepared are then sent to another air-permeable container to substantially evaporate and remove moisture by ventilation and / or heating, and at the moisture removal temperature, pre-expansion of polystyrene beads is promoted to be completed and pre-expanded. Sodium borate is adhered to the surface of the polystyrene beads showing finer irregularities in a solid state; (d) Sodium borate-supported pre-expanded polystyrene beads from step (c) are stored; (e) Sodium borate-supported pre-expanded polystyrene beads are stored. Introduce into the mold, heat with steam, and polish (1) Forming a single expanded polystyrene block by making the len beads complete foaming and making their surfaces tacky, and also fused together by slight pressure; (f) cooling the molded block. Solidifying; an insect control polystyrene foam insulation made by a method comprising: 2. The insect control polystyrene foam insulation according to claim 1, wherein the controlled temperature of the aqueous sodium borate solution in step (a) is in the range of 50 to 90 ° C., preferably 55 to 70 ° C. 3. Sodium borate is sodium metaborate (NaBO ₂ ), sodium tetraborate (Na ₂ B ₄ O ₇ ), sodium pentaborate (Na ₂ B ₅ O ₈ ), sodium hexaborate (Na ₂ B ₆ O). ₁₀ ), sodium octaborate (Na ₂ B
_8. The insect control polystyrene foam insulation of claim 1 selected from the group consisting of ₈ O ₁₃ ), sodium diborate (Na ₄ B ₂ O ₅ ), and hydrates thereof, and mixtures thereof. 4. The insect control polystyrene foam insulation according to claim 3, wherein the sodium borate is sodium octaborate tetrahydrate. 5. The insect control polystyrene foam insulation according to claim 1, wherein the concentration of sodium borate in the product polystyrene foam insulation is at least 2500 ppm based on the weight of polystyrene. 6. The concentration of sodium borate in the product polystyrene foam insulation is 300 based on the weight of polystyrene.
The insect control polystyrene foam heat insulating material according to claim 6, which is in the range of 0 to 6000 ppm. 7. The insect control polystyrene according to claim 1, further comprising (f) subjecting the obtained molded block to a slicing process and / or another cutting process to obtain a predetermined size. Foam insulation. 8. The steel according to any one of claims 1 to 7, wherein sodium borate is deposited in the form of a layer or a thin film on the fusion grain boundaries between the expanded polystyrene beads and in the vicinity thereof over the entire expanded polystyrene heat insulating material. One insect control foam polystyrene insulation. 9. A composite insulation comprising the insect control polystyrene foam insulation of claim 8. 10. The composite heat insulating material according to claim 8, which is in the form of a panel in which a metal plate, a plastic plate or a wood-based plate is attached to one or both sides of the insect control polystyrene foam layer.