JPH04462B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an asphalt foam previously proposed by the applicant, and in particular to a method for producing porous asphalt board from its cutting waste and poorly formed products.

Conventionally, urethane foam with open cells is impregnated with molten asphalt or asphalt emulsion to provide the water repellency and gradual restoring force required for joint materials as joint materials for houses, vehicles, and civil engineering works. It is widely used (hereinafter, a product with the water repellency of asphalt and the resilience of foam will be referred to as asphalt foam). However, conventional asphalt foam has the problem of not being able to obtain uniform quality due to so-called uneven impregnation, and when repeatedly compressed, the asphalt attached to the cell walls of the foam is gradually lost due to impregnation, resulting in poor quality. There was a problem with the decrease in

Therefore, the applicant has previously proposed a method for producing asphalt foam that does not cause quality unevenness or quality deterioration. This production method is characterized by adding and mixing a urethane prepolymer obtained by reacting a polyether polyol with an ethylene oxide content of 15% or more with an organic isocyanate to an aqueous asphalt emulsion and foaming the mixture. be.

In this case, when the aqueous asphalt emulsion and urethane prepolymer are mixed and stirred, the urethane prepolymer undergoes a polymerization reaction and polyurethane linkage grows, and the water in the asphalt emulsion and the free isocyanate groups in the urethane prepolymer are It reacts as shown below to generate carbon dioxide gas, resulting in a foaming effect.

-N=C=O+H ₂ O→-NH ₂ +CO ₂ Then, asphalt particles are uniformly dispersed throughout by the foaming action of the carbon dioxide gas generated above and the mechanical mixing operation by stirring, resulting in uniform quality. Moreover, since the asphalt itself constitutes the foam base, the asphalt does not separate from the foam base and cause quality deterioration as in the past, and has excellent durability. In addition, in the above production method, the reason why a urethane prepolymer obtained from a polyether polyol having an ethylene oxide content of 15% or more is used is because the asphalt component is added as an aqueous emulsion as described above. This is because the urethane prepolymer described above is required to have good affinity with water, and the above-mentioned urethane prepolymer satisfies this requirement.

When the applicant began research on the manufacturing method according to the above invention, his main interest was in asphalt foam as a joint material. However, as a result of various studies conducted on the asphalt foam obtained by the above-mentioned manufacturing method, it was found that this asphalt foam has a cellular structure with a large amount of asphalt component, and has excellent sound absorption and sound insulation properties. It was found that there were. Therefore, the asphalt foam obtained by the above-mentioned manufacturing method can be suitably used as an automobile floor material or a dash panel, and research in this field is currently being actively continued.

By the way, when the asphalt foam obtained by the above manufacturing method is used for specific purposes such as joint material or flooring material for automobiles, the asphalt foam that has been foam-molded into a large block is generally used in a suitable manner. It is used by slicing it into thick sheets, and in some cases, it is further cut into various shapes or punched. For this reason, a large amount of processing waste is generated before the final product is made, and there are also products with poor surface properties such as the epithelium and hypodermis of asphalt foam blocks.
There is a considerable amount of defective products that cannot be made into finished products, such as defective products that occur during foam molding. For this reason, methods for effectively utilizing these cut scraps, defective products, etc. have been brought up as an issue for consideration.

The present invention has been made in view of the above-mentioned circumstances, and it manufactures porous asphalt boards using asphalt foam processing waste and defective products from foam molding produced by the method proposed by the previous applicant as raw materials. The present invention provides a method.

That is, the first invention of the present application is characterized in that the asphalt foam produced by the method previously proposed by the applicant is cut into pieces, and the pieces are spread almost flat, compressed, and heated to form a plate shape. That is.

In addition, the second invention of the present application is to form a board by adding an appropriate amount of polyurethane prepolymer and a catalyst as necessary to the above-mentioned shredded asphalt foam, and then spreading it substantially flat, compressing and heating it. It is characterized by being molded into a shape.

As mentioned above, the great advantage of the present invention is that cut scraps of asphalt foam and defective molded products can be used as raw materials. Of course, this is also possible.

When carrying out the present invention, first, the above-mentioned asphalt foam is pulverized using a pulverizer or the like. This yields asphalt foam strips with a diameter of approximately 2 mm to 20 mm. The shape of the pieces may be any shape, such as a square or a circle, and a normal pulverization method yields irregularly shaped pieces having a mixture of these shapes.

In the first invention of the present application, the strips of asphalt foam are spread as they are to a predetermined thickness, and are compressed and heated to form a plate. The compression ratio at this time can be set arbitrarily depending on the density and hardness of the target board, but from the viewpoint of formability, it is necessary to compress the board so that the final thickness is 1/2 or less.
Moreover, it is generally desirable that the heating temperature be about 120°C to 270°C.

When compressed and heated, the strips of asphalt foam become interconnected and integrated.
An asphalt board formed into a plate shape is obtained. This is thought to be because the asphalt foam has high viscoelasticity, and the asphalt contained integrally in the foam acts as a linking agent. In this respect, the invention differs from conventional manufacturing methods for manufacturing so-called chip slabs from strips of flexible polyurethane foam. That is, when manufacturing a chip slab, since the urethane foam itself does not have viscoelasticity, it cannot be integrated unless a small amount of polyurethane prepolymer is added and mixed and compressed while blowing steam.

On the other hand, the second invention of the present application uses a polyurethane prepolymer and, if necessary, a catalyst added to the asphalt foam strips as a binder,
The purpose is to manufacture a more strongly integrated asphalt board. Although a binder is used in this way, there is no need to blow in steam as in conventional chip slab manufacturing methods. That is, since some of the water used as the asphalt emulsion remains unreacted in the asphalt foam,
The added polyurethane prepolymer can react with this unreacted water and act as a binder.

In addition, in both the first invention and the second invention, the asphalt foam produced as described above is porous due to the original asphalt foam, and therefore has excellent sound absorption and sound insulation properties. It can be suitably used as building materials such as floor materials and wall materials, or as floor materials and joint materials for automobiles. Further, according to the present invention, asphalt boards having a desired hardness, ranging from soft to hard, can be manufactured depending on the intended use.

Examples of the present invention will be described below.

Example 1 (First invention) (1) Production of asphalt foam 50 parts by weight of blown asphalt, 50 parts by weight of water, and 0.3 parts by weight of sodium alkyl sulfate as a surfactant were mixed in a homogenizer (mixing and dispersing machine).
The mixture was uniformly mixed and dispersed to obtain an aqueous asphalt emulsion.

Apart from this, ethylene oxide content 60
% polyether polyol (molecular weight 3000, 3
(functional) and tolylene diisocyanate were reacted at 85° C. for 4 hours with stirring to obtain a urethane prepolymer containing 9.5% of free isocyanate groups.

Next, 30 parts by weight of the above urethane prepolymer was mixed with 100 parts by weight of the aqueous asphalt emulsion obtained above, foamed, and the specific gravity
Obtained an asphalt form of 0.15.

(2) Manufacture of asphalt board The asphalt foam obtained as described above is crushed into pieces by a crusher, and asphalt board is manufactured from the pieces of the asphalt foam using the equipment shown in the attached drawings. I did it.

In the figure, reference numerals 1 and 2 are endless belts constituting a double conveyor, which are disposed through the oven 3. The asphalt foam strips 11 are continuously supplied onto the endless belt 1, and are made into a predetermined thickness with a doctor blade 4 and fed between the endless belts 1 and 2.
It is introduced into an oven 3 maintained at a temperature of approximately 170°C. The strip of asphalt foam 11 is heated during its passage through the oven 3 and at the same time is compressed by compression rolls 5,6. The plate-shaped asphalt board 12 thus obtained is continuously conveyed to a predetermined position by a conveyor belt 7, cut into a desired size, and loaded onto a cart 8. In this way, asphalt boards 13 with a thickness of 3 mm and a specific gravity of 0.45 could be manufactured continuously.

Example 2 (Second invention) Strip of asphalt foam used in Example 1
Polyurethane prepolymer 15 to 100 parts by weight
parts by weight and 0.2 parts by weight of dibutyltin dilaurate were added and mixed. When this was supplied to the apparatus shown in the attached drawing in the same manner as in Example 1, an asphalt foam with a specific gravity of 0.38 could be produced.

As described in detail above, according to the present invention, it is possible to remove the asphalt foam produced by the method proposed by the previous applicant, which is porous and has excellent sound absorbing and sound insulating properties, even from processed and cut waste and defective products during foam molding. It is possible to produce asphalt boards that are asphalt boards, and to make effective use of processed cutting waste and defective molded products.

[Brief explanation of drawings]

The accompanying drawings are explanatory diagrams showing an example of an apparatus for carrying out the present invention. 1, 2...Endless belt, 3...Oven, 4...Doctor blade, 5, 6...Press roll, 7...Transport belt, 8...Dolly.

Claims (1)

[Claims] 1. Asphalt foam is produced by adding and mixing a urethane prepolymer obtained by reacting a polyether polyol with an ethylene oxide content of 15% or more with an organic isocyanate into an aqueous asphalt emulsion and foaming the mixture. 1. A method for manufacturing an asphalt board, which comprises cutting the asphalt foam into pieces, and then forming the pieces into a plate shape by spreading the asphalt foam substantially flat, compressing and heating it. 2. An asphalt foam is obtained by adding and mixing a urethane prepolymer obtained by reacting a polyether polyol with an ethylene oxide content of 15% or more with an organic isocyanate into an aqueous asphalt emulsion and foaming the asphalt foam. A method for manufacturing an asphalt board, which comprises cutting it into pieces, adding an appropriate amount of polyurethane prepolymer and, if necessary, a catalyst, and then forming the asphalt board into a plate shape by spreading the pieces substantially flat, compressing and heating them. .