JPS61152741A - Production of asphalt foam - Google Patents

Abstract

PURPOSE:To produce an asphalt foam free from stickiness, and having excellent processability, by impregnating an asphalt emulsion to a foamed sheet having open cell structure, applying a plastic emulsion solution to the surface and drying the product with heat. CONSTITUTION:The objective asphalt foam can be produced by impregnating (A) an asphalt emulsion produced by stirring and dispersing 1pt.wt. of asphalt mechanically in 0.3-2pts.wt. of water using cationic or anionic surfactant, etc. in (B) a foamed sheet having a thickness of 5-30mm and having open cell structure, preferably a urethane foam sheet, optionally drying the impregnated emulsion, applying (C) a plastic emulsion solution, e.g. polyvinyl chloride emulsion, acrylic resin emulsion, etc., to the surface of the sheet preferably by a transfer roll and driving the product with heat.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for producing asphalt foam, and particularly to an improved method for obtaining an asphalt foam with excellent workability.

[Technical background of the invention]

Urethane foam with open cells is impregnated with molten asphalt, giving it water repellency and slow restoring power, and has been widely used as a joint material. Asphalt foam has the resilience of

Furthermore, it has been revealed that the above-mentioned asphalt foam not only has properties suitable for joint material, but also has excellent sound absorbing and sound insulating properties, as well as earthquake proofing properties.

Therefore, in recent years, it has been effectively used in applications that take advantage of its sound and earthquake insulation properties, such as automotive flooring materials.

[Problems with background technology]

However, in the conventional asphalt foam mentioned above, since the asphalt is simply attached to the cell walls of the foam by impregnation, for example, during punching, the asphalt oozes out to the surface and becomes sticky, and other materials There were problems such as staining and deterioration of workability.

Furthermore, since the viscosity changes when the heating temperature conditions of the molten asphalt differ, there is a problem that uniform impregnation is not achieved.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and provides an efficient manufacturing method capable of obtaining an asphalt foam with good workability and no stickiness due to asphalt oozing.

[Summary of the invention]

The method for producing asphalt foam according to the present invention is characterized by impregnating a foam sheet with open cells with an appropriate amount of asphalt emulsion, then applying and impregnating the surface with a plastic emulsion solution, and then heating and drying. be.

Note that after impregnation with the asphalt emulsion, if necessary, the plastic emulsion solution may be applied after drying.

As the foam sheet with open cells used in the present invention, a urethane foam sheet is most suitable; however, any foam sheet other than urethane foam may be used as long as it is an open cell foam. may be arbitrary, but generally one of 5+u+ to 30 mm is used.

The asphalt emulsion in the present invention may be one obtained by a known emulsification technique, such as mechanically stirring and dispersing asphalt in water using a cationic or anionic surfactant. In this case, the asphalt may be either natural asphalt, straight asphalt obtained as a residue from distillation of asphalt-based crude oil, or blown asphalt obtained by oxidative polymerization by introducing heated air into this asphalt. Although the ratio of asphalt to water is not particularly limited, it is preferably 0.3 to 2.0 parts by weight of water to 1 part by weight of asphalt, and 0.3 to 2.0 parts by weight of water.
If it is less than 3 parts by weight, it will be difficult to obtain a uniform emulsion, and if it exceeds 2.0 parts by weight, the viscosity will increase and impregnating properties will decrease, resulting in so-called uneven impregnation.

The plastic emulsion solution in the present invention includes polyvinyl chloride resin and acrylic resin.

A material made of polyurethane resin or the like, which is generally commercially available, can be used.

In carrying out the present invention, the asphalt emulsion described above is first impregnated into the foam sheet having open cells. As a method of impregnation, a dipping method using a bathtub, a spray method, a transfer method, etc. can be used. In any case,
Since the asphalt emulsion is adjusted to a stable and desirable viscosity, it is possible to uniformly impregnate the entire surface without causing uneven impregnation.

Next, the plastic emulsion solution described above is applied to the surface of the sheet, either directly or after drying. As a coating method, a spray method, a transfer method, or any other arbitrary method can be used. However, it is preferable that the plastic emulsion solution is impregnated from the surface to some extent, and from this point of view, a method using a transfer roll is preferable.Subsequently, by drying this, the desired 6 asphalt foam can be obtained.

The asphalt foam produced in this manner has a structure in which the surface is covered with a hardened layer of plastic emulsion solution, thereby preventing asphalt from seeping out. Therefore, the situation of stickiness and contamination of other materials is avoided,
In addition, good workability can be obtained even when punching several sheets stacked one on top of the other.

[Embodiments of the invention]

An embodiment of the present invention will be described below.

Example (L) Preparation of asphalt emulsion 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 uniformly mixed and dispersed using a homogenizer (mixing and dispersing machine) to form aqueous asphalt. I got an emulsion.

(2) Production of asphalt foam Using the asphalt emulsion prepared as described above, asphalt foam was produced as follows by the method shown in the attached drawings.

That is, in the figure, l is a dipping tank, and the dipping tank is filled with the asphalt emulsion 2. A pair of dipping rolls 31 and 32 are arranged in the asphalt emulsion 2, and the upper end of the dipping tank l A squeezing roll 41 v 42 is arranged in the section. The foam sheet to be impregnated has a density of 0.016 g/cm” and a thickness of 10 m @
17) A flexible polyurethane foam sheet IO was used, which was continuously fed from a supply roll through dip rolls 3 K, 3 x and squeeze rolls 41 + 42.

During this time, the asphalt emulsion is impregnated with the impregnating roll, while the excess asphalt emulsion is removed with the squeezing roll. In this way, the wet density of the polyurethane foam 10 is 0.28 g/cm.
The amount of asphalt emulsion impregnated was adjusted so that

Subsequently, the polyurethane foam 10' impregnated with asphalt emulsion is transferred to a pair of transfer rolls 51 + 5.
2 to impregnate the surface of the polyurethane foam 10' with the acrylic emulsion 7 stored in the supply tanks 61 + 62. Furthermore, this was continuously introduced into a drying oven 8 and dried and hardened to form an asphalt foam, which was then wound into a roll to form a product.

The asphalt foam obtained in the above example had characteristics as an asphalt foam, such as slow recovery speed and excellent sound absorbing and sound insulating properties. Furthermore, even when several sheets of this material were stacked and punched, no asphalt oozed out, and the material had good workability.

〔Effect of the invention〕

As detailed above, according to the present invention, an asphalt foam with good workability that prevents asphalt from seeping out during processing can be obtained, and in addition, excellent flame retardance can be imparted to the asphalt foam. etc., S remarkable effects can be obtained.

[Brief explanation of the drawing]

The accompanying drawings are explanatory diagrams showing an example of an apparatus for carrying out the method for manufacturing asphalt foam according to the present invention. 1... Impregnation 411.2... Asphalt emulsion, 3□, 32... Impregnation roll, 41.42... Squeezing roll, 51 r 52... Transfer roll, 81 +
62... Supply tank, 7... Acrylic emulsion solution, 8... Heating oven

Claims (2)

[Claims] (1) A method for producing an asphalt foam, which comprises impregnating a foam sheet with open cells in an appropriate amount with an asphalt emulsion, then applying and impregnating the surface with a plastic emulsion solution, and then heating and drying. (2) After impregnating the foam sheet with an appropriate amount of asphalt emulsion, a step of drying the foam sheet is added before applying the plastic emulsion solution to the surface. 1) The method for producing asphalt foam as described in section 1).