JPS5940863B2 - Manufacturing method of sealing material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a sealing material, and more particularly to a method for manufacturing a flexible urethane foam sealing material mainly consisting of closed cells and having excellent airtightness and waterproof properties.

Traditionally, flexible urethane foam sealants aimed at airtightness and waterproofing include (1) soft urethane foam impregnated with a bituminous or rubber waterproofing agent;
) Polyurethane foam Open-cell foam made by adding various hydrophobic materials such as bituminous and animal and vegetable oils to the foaming raw material compound, (
3) All products are based on open-cell urethane foam, such as urethane foam with fine cells.

(1) is made by impregnating open-cell flexible urethane foam with a solution or dispersion of a waterproofing agent and drying it, which increases the bulk specific gravity and requires an impregnation and drying process, which makes the operation cumbersome and reduces productivity. Not only is the temperature low, but there is also a risk of air pollution, harm to the human body, and fire due to the solvent, and there are many problems such as staining the mating substrate when using this product and being temperature sensitive. Moreover, airtightness and waterproof properties are only achieved when the urethane foam is compressed.

(2) and (3) are open-cell flexible urethane foams themselves, and most of the foaming raw materials used are combinations of known raw materials, and hydrophobic materials are selected to make the cells finer. This provides airtightness and waterproofness for the first time.
Many polyhydroxyl compounds that react with isocyanate compounds to form polymers have been known for a long time, including polyester polyols, polyether polyols, castor oil derivatives, tall oil derivatives, and their hydroxyl group compounds.
Hydrocarbons such as bituminous and castor oil are also known as hydrophobic materials added to the foaming raw material. All of the above-mentioned airtight and waterproof flexible urethane foam sealants are open-cell flexible urethane foams consisting of an aggregate of communicating fine cells, and all of them can be formed into foam at normal pressure.

The production of urethane foam at normal pressure is completed through the processes of mechanical mixing of raw materials, injection into a mold, foaming, open cell formation, and curing, and the following behavior is observed to occur during this process.

(a) Normal reaction Mixing → foaming → deaeration to open cells → curing (
b) Abnormal reaction Mixing → foaming degassing collapse → hardening (c
)〃 Mixing → Foaming → Deaeration and collapse - → Curing (d) Abnormal reaction Mixing → Foaming → Shrinkage → Curing The behavior necessary for manufacturing flexible urethane foam is shown in (a), and normal open-cell property. A urethane foam is obtained.

In both cases (b) and (c), no foam is formed and the resin is turned into a resin by curing, resulting in non-uniform and discontinuous macroscopic bubbles. In (d), the diffusion equilibrium between the gas inside the bubbles generated by the reaction and the atmosphere is not established, and the pressure inside the bubbles is lower than the atmospheric pressure, so the urethane foam contracts due to the pressure difference, and in a reduced pressure atmosphere. Foam can be produced by foaming under normal pressure, but even if foamed under normal pressure, the bubbles shrink, resulting in a lumpy, high-density cured resin product. The present invention focuses on the behavior of foaming and curing during the generation of such soft urethane foam, and
The present invention relates to an airtight and waterproof soft urethane sealing material mainly composed of closed cells obtained by a urethane foaming process that shrinks due to the method d).

That is, in the present invention, in the process immediately before the start of shrinkage after foaming, an abnormal reaction is caused in which the foam shrinks and cannot become a soft urethane foam if it is left as it is.
Either promptly remove the skin to promote gas diffusion equilibrium inside and outside the cells, or (2) partially destroy the cell walls forming closed cells by mechanical compression using a roll press or the like immediately before shrinkage after foaming. This invention relates to a method for manufacturing a soft urethane sealant mainly consisting of closed cells by preventing the shrinkage of the cells, and the produced urethane foam sealant exhibits excellent airtightness and waterproofness due to the presence of closed cells. . The cell pore diameter of the foam is generally different in size, and the shape of each cell is also not constant, but it was confirmed that the air permeability of the foam corresponds to this, and that the finer the cells, the lower the air permeability. In order to impart excellent waterproof properties to open-cell soft or semi-rigid polyurethane foam sealants, the air permeability at a thickness of 107 nm must be 10 cc/c! 1
．． In other words, the essential condition is that the cell pore diameter is small, but the soft polyurethane foam sealing material mainly composed of closed cells obtained by the present invention has an air permeability of 20 cc at a thickness of 1071 tm. /
Cil. /Sec or less, it was found that sufficiently satisfactory waterproof properties could be obtained.

A visual comparison of the surface observation of the foam material revealed that the open-cell polyurethane foam sealing material with excellent waterproof properties has finer surface cells than the polyurethane foam sealing material mainly composed of closed cells obtained by the present invention. It is observed that it has a dense appearance and the number of cells per inch reaches 80 to 100, and when observed using a microscope,
In the case of the product of the present invention, the cell wall on the surface of the foam material remained, and it was observed that some of the cell wall was locally destroyed and pinholes or cracking occurred. It was observed that the polyurethane foam sealant had excellent open cell properties, but had relatively large cell pore diameters, with the number of cells per inch being around 50. Polyols used as main components in the present invention include polyester polyols, basic organic acids such as adipic acid, phthalic acid, and succinic acid, and polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, and trimethylolpropane. or a mixture thereof; polyether polyols, such as poly(oxypropylene ether) polyol, poly(oxyethylene ゜propylene ether) polyol; acrylic polyol; hydroxyl group-containing oil derivatives, such as castor oil derivatives, tall oil derivatives ; and other hydroxyl group-containing compounds, but are not limited thereto.

From the viewpoint of hydrophobicity and water repellency, consideration should be given to using poly(oxyethylene propylene ether) polyols in which the proportion of oxypropylene moieties is higher than the proportion of oxyethylene moieties, and the use of polyols produced from long fatty acid chains. is necessary. As an isocyanate compound, commonly used tolylene diisocyanate (TD
I), 4,4'-diphenylmethane diisocyanate (
MDI) can be used alone or in combination.
To obtain an open-cell polyurethane foam sealant with excellent waterproof properties, use polymethylene polyphenylene isocyanate such as MDI alone or TDI in addition to it.
It is preferable to mix 20% by weight or less of
The major difference in the polyurethane foam sealing material of the present invention, which mainly consists of closed cells, is that sufficient waterproofness can be obtained even with TDl alone. Hydrophobic components added to the foaming feedstock used in the present invention include bituminous materials such as asphalt, solid, semisolid, liquid hydrocarbon compounds and/or similar hydrocarbon compounds.

However, it is not limited to this. If the foam does not contain any hydrophobic component as a constituent component, even if it is foamed, the cells will collapse and become punctured, or the foam will become open cells.

That is, in order to form closed cells, the hydrophobic component is an indispensable component. However, the blended amount is 40 weight of polyol? If the temperature exceeds that level, stable closed cells cannot be obtained. Therefore, in the present invention, the hydrophobic component is an essential component, but its amount should be 40% by weight of the polyol. According to the present invention, by reducing the amount of the hydrophobic component to 40% by weight or less of the polyol, there is no need to particularly heat the hydrophobic component, and the temperature is stable even at a low temperature of 40°C or lower, especially around 30°C. Closed cells can be obtained. Examples of the blowing agent that forms the foam include water and trichloromonofluoromethane (CC'3F). but,
It is not limited to this. Examples of the catalyst include, but are not limited to, tertiary amines, such as DABCOl organotin compounds, such as tin catalyst T-9 (manufactured by Yoshitomi Pharmaceutical Co., Ltd.) dibutyltin dilaurate. Examples of the cell stabilizer which is an optional component include, but are not limited to, silicone stabilizers.

Foam is manufactured by adding bituminous and/or hydrophobic components to the main raw material, polyol or polyisocyanate compound.
Alternatively, a hydrocarbon compound similar to this is dissolved or dispersed, and this is stirred under heating to prepare a mixed solution containing a polyol or a polyisocyanate compound.

If other main raw materials, a blowing agent, a catalyst, and if necessary, a blowing aid, a surfactant, etc. are added to the thus obtained mixed liquid containing the first main raw material and mixed vigorously, the reaction will immediately begin, resulting in a foaming reaction and a polymerization reaction. occurs and a polyurethane polymer consisting of closed cells is obtained. The above-mentioned hydrophobic component is added to a mixture of a polyol and a polyisocyanate compound to prepare a mixed solution, and a blowing agent, a catalyst, and if necessary, a blowing aid, a surfactant, etc. can also be added thereto.

The above compound is injected into a mold lined with kraft paper and foamed, and just before the start of shrinkage, the lining paper is removed and the outer skin is removed (to promote gas diffusion equilibrium inside and outside the cell, or by machine such as a roll press). 30-50% depending on compression
By compressing the cell wall forming closed cells, the minimum number of cells sufficient to prevent the shrinkage of the foam is destroyed, resulting in pinholes or cracking in the cell wall, and it is 10 m77! Air permeability in thickness is 20cc/C
A soft polyurethane foam sealing material consisting mainly of closed cells with a volume of 7 l/Sec or less is obtained. The minimum amount of cells that must be destroyed to prevent shrinkage of the foam varies depending on the size of the foam, etc., but is usually between 1 and 40 (!). If the foam is relatively small, it is necessary to use a relatively low value in the above range, and if the foam is relatively large, it is necessary to use a relatively high value in the above range. Example 1 100 parts by weight of polyether triol TG3OO7 (manufactured by Dainippon Ink Co., Ltd.) whose main material is polypropylene glycol and 30 parts by weight of a hydrocarbon whose main material is asphalt at about 30°C
Parts by weight, 0.5 parts by weight each of amine catalyst DABCO・33LV (manufactured by Sankyo Air Products Co., Ltd.) and tin catalyst T-9 (manufactured by Ketomi Pharmaceutical Co., Ltd.), 4 parts by weight of water, silicone-based stabilizer (Nippon Unica Co., Ltd.) A blend was prepared by adding 32 parts by weight of isocyanate compound TD and 1 part by weight of the isocyanate compound TD.

This mixture was used in a cubic mold with a width of 30cm, a height of 30CTL, and a length of 30cm7rL, each lined with release paper or kraft paper, and a width of 30CT lined with release paper or kraft paper! The mixture was poured into a mold with L1 height of 30 cr and IL1 length of 2 m, and left at room temperature to foam. Example
2 Foaming was carried out under exactly the same conditions as in Example 1, except that 10% of the polyether triol in Example 1 was replaced with Diol MP-600 (manufactured by Dainippon Ink Co., Ltd.).

The following tests were conducted on both the foams of Example 1 and Example 2, and the same results were obtained in both cases.

(1) If you take it out of the mold and leave it as is, it will shrink.

Once something is left unattended after shrinking, it will not return to its original state no matter how much it is compressed. (2) If the product from which the release paper has been removed will be left alone, it will shrink, but if you compress it by 30% and destroy part of the cell wall before the shrinkage starts, the compressed product will return to its original shape.

(3) The foamed product in a cubic mold with 30 CTIL on each side will shrink slightly after the kraft paper is removed, but approximately 2
Leave it for 4 hours and it will return to its original shape.

However, if a long object with a length of 2 m is left without the kraft paper, it will shrink considerably and will not recover. After being compressed by 30% compression just before the start of contraction, it can be restored to its original shape and can maintain its original shape even after 24 hours. This is because, unlike release paper, when the kraft paper is removed, the skin of the foam is peeled off at the same time and part of the cell wall is destroyed, which prevents shrinkage of the foam in the case of a small sample such as a cube with 30 CTL on each side. This is thought to be because the minimum amount of cells sufficient to obtain the amount was destroyed. However, in the case of a 2 m long product, even if the outer skin of the foam is peeled off and a portion of the cell wall is destroyed, the minimum amount of cell destruction required to prevent the foam from shrinking cannot be reached. Therefore, in the case of a 2 m long product, it is thought that it was necessary to compress the foam by 30% just before the start of shrinkage to destroy the minimum amount of cells sufficient to prevent the foam from shrinking. Note that even if a 2m long object is still attached to the kraft paper, it will return to its original shape as long as it is compressed by 30%.

(4) Foamed in a cubic mold of 30 CTrL on each side, with the surface film removed by cutting, it will shrink slightly, but will return to its original shape if left for about 24 hours.

However, the 2 m long object was compressed immediately before the start of shrinkage (3001), and was restored to its original shape after compression. This reason is also considered to be the same as stated in (3). Next, an airtight/waterproof test was conducted on the sealing material mainly composed of closed cells of the present invention.

In conducting this test, the following comparative samples were also prepared and compared with the products of the present invention. Comparative Example 1 A commercially available soft urethane foam SL manufactured by Inoue MTP Co., Ltd. with a bulk specific gravity of 40 k9/M3 was impregnated with a petroleum-based bituminous solution containing asphalt as a main component, and the bulk specific gravity after drying was 140 kg/M.
I made a product that is 3.

Comparative Example 2 Commercially available soft urethane foam RS-40 manufactured by Inoue MTP
was used as is.

This sample is an open cell foam with the exact same composition as in Example 2 except that the hydrocarbons were omitted, but with different proportions. The above (
4) The form of Example 1 from which the surface film was removed by cutting a small sample of 30 CfIL on each side, 2 of (3) above.
The foam of Example 2 which was compressed by βO% with a long piece of kraft paper attached, the foam impregnated with bituminous material of Comparative Example 1, and the foam containing no bituminous material of Comparative Example 2 were sliced. Thickness 3mm, 10mm and 20m7
! I made an L sheet.

A 3-thick sheet is 30C! A bag was made by fixing the four corners of the sample on each side of RL to a frame with a hollow part, and the water depth was 100 m.
Waterproofness was evaluated by pouring water to the bottom and observing the state of water leakage and wetness on the bottom surface. thickness 10
The ventilation resistance of the 5 mm sheet was measured according to JIS-L-1004 by the Francil type method of woven fabric air permeability test.

Thickness 20m77! This sheet is further cut to form a rectangular parallelepiped A with a height of 20 mm x width of 20 mm x length of 100 mm and a height of 407 mm! After obtaining a rectangular parallelepiped B measuring Lm x width 20 mm x length 100 mm, a water pressure test was conducted using the water pressure test apparatus shown in the figure.

The apparatus shown in the figure has a container 1 having a rectangular opening 4 with a height of 10 mm and a width of 100711 m, a water pressure pump 2, a pressure gauge 3, and a test sample storage part with a height of 10 mm, a width of 20 mm, and a length of 100 mm. It consists of a test sample storage device 5.
If the test sample 6 is a rectangular parallelepiped A, it is 1 in the height direction.
/2, and in the case of rectangular parallelepiped B, it is compressed to 1/4 in the height direction, and the rectangular parallelepiped A or B is placed in the test sample storage device 5.
After fitting it into the container, fill the container 1 with water and turn on the water pressure pump 2.
The water pressure resistance was read using a pressure gauge 3. These results are shown in Table-1.

Table 1 shows that the sealing material mainly composed of closed cells of the present invention has significantly improved airtightness compared to conventional open-cell flexible urethane foams that are commercially available for the purpose of airtightness and waterproofing, and is waterproof when compressed. It can be seen that the performance has also been significantly improved.

[Brief explanation of drawings]

The figure is a schematic diagram of a water pressure test device used in Examples and Comparative Examples of the present invention. 1... Container, 2... Water pressure pump, 3.
...Pressure gauge, 4...Opening, 5...
... Test sample storage device, 6 ... Test sample.

Claims (1)

[Claims] 1 Main ingredients are polyol and isocyanate compound,
In addition, as a hydrophobic component, bituminous and/or similar hydrocarbon compounds with a temperature of 40°C or less are added to the polyol.
0% by weight or less, and a blowing agent and a catalyst are foamed, and immediately before the resulting foam begins to shrink, the skin of the foam is peeled off or the foam is mechanically
By compressing 0%, 1-40% of the cells of the foam are destroyed and the air permeability at 10mm thickness is 20cc/cm.
A method for producing a sealant, characterized by obtaining a sealant mainly consisting of closed cells with a cell diameter of ^2/sec or less.