JPS5839171B2 - Method for manufacturing porous material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a porous material having continuous pores and having high abrasion resistance and elasticity.

Conventionally, porous materials are produced by foaming during molding, but other methods include extracting the filler from a molded product containing the filler using water, an aqueous mineral acid solution, or other appropriate solvent to obtain a porous material. are generally known, but each has the following problems.

In other words, in the former case, the type and amount of blowing agent and resin used,
Although it is possible to adjust the pore size, porosity, and strength of elasticity by changing the molding conditions, etc., it is difficult to disperse a foaming agent with a constant particle size into the molded product, and it is difficult to heat it during foaming. However, there is a problem in that it is difficult to obtain pores with a constant pore size or completely continuous pores due to the difficulty of uniform heat conduction in order to achieve uniform foaming. There was a problem in that it was difficult to obtain a homogeneous porous body because it was difficult to uniformly disperse the filler therein.

The present invention uses micro hollow spheres 20 with a particle size of 50 to 1000 μm to produce a porous material having a certain number of continuous pores.
The present invention relates to a manufacturing method in which a porous material is obtained by blending ~90 parts by weight with 10 to 80 parts by weight of a synthetic or natural elastomer and then molding to destroy microscopic hollow spheres contained in the molded product. Explain in detail.

The most distinctive feature of the present invention is the use of microscopic hollow spheres.

That is, usable micro hollow spheres include glass micro balloons, glass micro balloons, and micro hollow carbon spheres of 50 to 1000 microns.

In this case, micro hollow spheres of 50μ or less have the problem of being difficult to break during the pressurization process described later, and those of 100μ or more are easy to break during the kneading stage before the pressurization process, resulting in a problem of decreased porosity. So I don't like it.

Synthetic or natural elastomers that are kneaded with these micro hollow spheres and used for molding include thermoplastic urethane resins, thermosetting urethane resins, ethylene vinyl acetate copolymers,
There are chloroprene rubber, styrene butene rubber, phtadiene rubber, butyl rubber, imprene rubber, natural rubber, nitrile rubber, ethylene propylene rubber, liquid chloroprene, liquid nitrile rubber, etc., and these rubbers may be used alone or in combination.

These elastomers can be appropriately selected and used as long as they are in a liquid state, a latex state, or a state that allows them to be added without destroying the hollow microspheres at the flow rate during mixing.

The mixing ratio of micro hollow spheres and elastomer can be determined according to the final porosity required, and the ratio is 1:1 to 3:1 (weight ratio), and the porosity is approximately 40 to 70%. You can get something.

In addition, vulcanization accelerators and crosslinking agents necessary for molding, and natural rubber itself has high strength, making it easy to reinforce and process, while synthetic rubber itself has extremely low strength. For reinforcing purposes, fillers such as lightweight calcium carbonate and silica are selected as appropriate and added at the same time as the microscopic hollow spheres are mixed.

Next, depending on the purpose, the uniformly dispersed product is molded into a rod or plate shape by vulcanization, extraction, injection, or other methods using pressure that does not destroy the microscopic hollow spheres.

Next, in order to form continuous pores, the microscopic hollow spheres are crushed by applying pressure with a roll or the like, but in this case, it is preferable to apply pressure in stages rather than all at once.

In other words, at the beginning of the pressurization, the sheet is passed between rolls that are about 30% of its thickness, and then passed between rolls that are gradually narrowed, thereby destroying the micro hollow spheres step by step, thereby preventing the application of sudden stress, and forming the sheet. There is no physical destruction or deformation of objects.

Incidentally, in order to make the formation of continuous pores more advantageous, a solvent such as toluene or xylene may be added.

The manufacturing method of the present invention is characterized in that pores are obtained by destroying micro hollow spheres, so that pores with a pore size suitable for the purpose can be obtained, and the destroyed micro hollow spheres remain in the molded product. Therefore, it acts as a reinforcing agent and, as a result, significantly contributes to improving wear resistance and bending resistance.

The embodiments of the present invention will be described in detail above.

In addition, "Example Middle" indicates parts by weight.

Example 1 100 parts of Parablene DN4806 (manufactured by Nippon Polyurethane ■, thermoplastic ether type polyurethane), glass microballoon IGIOI (manufactured by Emerson & Cuming, micro hollow spheres of borosilicate glass, average particle size 65μ, bulk specific gravity 0.194g/ cc) and 5 parts of dimethylformamide to lower the viscosity in a small Nigu, and add 1
Heat to 50-160°C and knead.

After kneading for 30 minutes, a sheet with a thickness of 5 mm is made using an extruder (in this case, the pressure is kept to about 50 kg/i).

Next, the glass microballoons contained in the sheet are destroyed by applying pressure in stages between 30% of the sheet thickness and 95 mm rolls, resulting in a porous material with an average pore diameter of 50 μm and a porosity of 43 μm. Obtained.

In addition, the usage ratio of glass microballoon and polyurethane (
When the same treatment was carried out at a weight ratio of 2:1.3:1, porous materials with porosity of 55φ and 68φ were obtained, respectively.

Example 2 Shirasu balloons were blended with liquid chloroprene under the following conditions.

LCR-X-050 (manufactured by Denki Kagaku Kogyo ■'100 parts liquid chloroprene) Tetraethylenepentamine (crosslinking agent) 8 parts Zn0
5 parts Mg0
5 parts Shira
part 650μ) The above mixture was vulcanized in a mold at 50°C for 7 days to give a thickness of 3 mounds,
A sheet of 200 x 200 mm was created.

Next, this sheet was passed between rolls with a thickness of 30 to 95 mm in stages (this pressure was applied) to destroy the Shirasu balloon, and a porous material with continuous pores with a porosity of 55 was obtained. Obtained.

When the porous material of this example was used as a stamp ink occluding body, it had excellent ink retention properties and the ink transferred well and evenly to the batten.

As explained above, the porosity of the present invention can be freely adjusted depending on the particle size and bulk specific gravity of the micro hollow spheres used, and the pores are formed simply by applying pressure. Since the microscopic hollow spheres remain, the strength is significantly improved compared to conventional porous materials, and it can be used in a wide range of applications, including the nibs of various writing instruments, stamp materials, cosmetics, and filter media.

Claims (1)

[Claims] 1. 10 to 80 parts by weight of synthetic leather or natural elastomer is blended with 20 to 90 parts by weight of microscopic hollow spheres such as glass balloons and glass microballoons with a particle size of 50 to 1000μ, and then the contained microscopic hollow spheres are destroyed. A method for producing a porous material, characterized by: