JPS5811124A - Forming for porous material - Google Patents

Abstract

PURPOSE:To produce porous material simply and economically by following method in which granular material is mixed with liquid thermosetting resin so that the surfaces of grains are coated with thermosetting resin, and then heated gas is pressed into or passed through said coated material, thereby hardening the thermosetting resin in the mixture. CONSTITUTION:When a porous body is formed by adhesively connecting many granular mateial, thermosetting resin (liquid monomer or polymer hardened at three demensional cross liking mechanism by using setting reagent e.g. epoxy resin) is coated at liquid state (preferably viscosity is below 2,000cm-poise) on the granular material (e.g. expanding pearlite included in inorganic foaming material is desirable, and the mean diameter of grains is above 0.3mm. but preferably above 0.5mm. are used) so that the surface of the granular materials are covered. Then they are heated and hardened by the gas such as steam or heated air. The mixed granular materials are filled in a forming mold with air holes. Heated gas is pressed into the forming mold and then passed through the mold. This is the best process for manufacture.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for molding a porous material, and more specifically, the present invention relates to a method for molding a porous material, in particular, by mixing a granular material with a liquid thermosetting resin, coating the surface of the granular material particles with the thermosetting resin, and The present invention relates to an improved method for molding a porous material, in which heated gas is forced into or passed through a coating to cure and mold the thermosetting resin.

(Background of the Invention) Currently, there are various types of porous materials, each of which is used in an appropriate location depending on its characteristics. For example, fibers such as glass wool or rock wool combined with a binder to form a mat are used for insulation or sound-absorbing materials, while wood chips combined with cement or organic adhesives are used as construction boards, etc. Sintered metal particles or glass particles are used for P materials, etc., and sintered inorganic foam particles bonded with inorganic or organic adhesives are used for sound absorbing materials, filter media, etc.

Currently, there are two methods for bonding granules: the method of sintering the granules as described above, and the method of using adhesives, but the former is limited by the material of the granules and requires advanced manufacturing techniques. and is expensive. The latter uses water-based adhesives (cement, water glass, etc. for inorganic adhesives, various emulsion-based adhesives for organic ones), thermosetting adhesives, and must be dried. Or heat curing is required.

Many of these materials inherently have poor thermal conductivity, and forming porous materials has conventionally consumed a large amount of thermal energy and time.

(Objective of the present invention) The present invention aims to form a porous material by bonding granular materials using a thermosetting resin, using a simple device, in a short time, with low energy consumption, and at low cost. The purpose is to provide an effective molding method for obtaining materials. The gist of this method is to change the external heating method used in the conventional method, and press hot gas directly into the molding material to perform hot molding.

(Method of the present invention) That is, in the method of the present invention, when forming a porous material by bonding countless granules, a thermosetting resin is mixed with the granules, and the surface of the granules is coated with the thermosetting resin. and heat the inside of this mixed coating (meaning a mixture of the granules and a thermosetting resin that adheres to the surface of the granules and coats the granules - hereinafter simply referred to as the mixed coating). This is a method of molding a porous material in which gas is pressurized and passed through to harden and mold the thermosetting resin covering the granular particles.

Any suitable method can be used to harden the thermosetting resin by pressurizing or passing heated gas into the mixed coating, but in the present invention, in particular, molding with ventilation holes is used. A mold is used to fill the mixed coating and heated air is forced into or passed through the mold, or the mixed coating is preformed and heated air pressure is forced into the preformed body, or The method of passing is adopted as the best method. In addition, specific details will be explained in the section of embodiments of the present invention described later.

(Particles) The granules used in the present invention are not particularly limited, and various types can be used. To illustrate this, examples of the inorganic granules include gravel, inorganic foam, etc., and examples of the organic granules include synthetic resins, resin beads, foamed beads, and the like. Among these, inorganic foams have heat resistance against water vapor and are lightweight, so molded products excellent as heat insulating materials and sound absorbing materials can be obtained. Furthermore, among the inorganic foams, expanded pearlite is the most preferable material for the granules used in the present invention because foam particles with strong strength and relatively large diameters can be obtained at low cost.

Expanded pearlite is made by crushing pearlite, pinestone, obsidian, etc. and then firing it at about 900°C to 1100°C to form a hollow body with the foaming components contained in the rock.

Among these expanded ξ-lites, obsidian pearlite in particular has a relatively large particle size ranging from 0.5 mm to several diaphragms, and products with a wide range of particle sizes can be obtained, and the surface of the particles is smooth and has no pores. There are almost no particles, and the inside has a so-called peak nest structure in which primary foam particles gather, so the particles are strong.

In the present invention, these granules preferably have an average particle diameter of Q, 3 mm or more, and more preferably flo, 5 mm or more. If the average particle size Q is less than 3 mm, the resistance when pressurizing heated gas, especially water vapor, will be large and it will be difficult to mold efficiently. Further, although there is no particular limitation on the upper limit of the average particle size, particles with a large particle size of 10 in or more have a weak strength even as a porous material and are inferior in practicality.

(Thermosetting resin) In the present invention, the thermosetting resin for bonding the granules is one that is made by curing a liquid monomer or polymer into a three-dimensional crosslinked structure using a curing agent, etc. In the present invention, the thermosetting resin is coated on the surface of the granules as a liquid, preferably with a viscosity of 2000 centipoise or less, and then heated and cured with a gas such as water vapor or heated air.

The thermosetting resin used in the present invention is not particularly limited, and widely used include epoxy resin, melamine resin, unsaturated polyester resin, urea resin, phenol resin, urethane resin, furan resin, liquid polybutadiene or modified products thereof. Of these, epoxy resins and liquid polybutadiene or modified products thereof are particularly preferred because they are not adversely affected by water vapor and can produce porous materials with high strength. Further, these are generally cured using a commonly used curing agent, and the curing agent is appropriately selected depending on the type of resin used. For example, formalin is used for curing phenolic resins, urea resins, melamine resins, etc., organic and peroxides are used for unsaturated polyester resins, liquid polybutadiene or its modified products, etc., and amines are used for curing epoxy resins etc. used as an agent. Note that it is not necessary to add a curing agent to materials that harden with moisture, such as urethane resins.

The thermosetting resin is preferably used in an amount of 3 parts by weight per 100 parts by weight of the granules.
It is used in an amount of at least 5 parts by weight, more preferably at least 5 parts by weight. If the amount is less than 3 parts by weight, the bond between the granules is weak and a good product cannot be obtained. There is no particular upper limit on the amount of thermosetting resin used, but even if 100 parts by weight or more is used, no significant improvement in strength can be expected and it is disadvantageous from an economic standpoint.

(Embodiments) Further details of the embodiments of the present invention]~〈First of all,
A thermosetting resin is mixed with the granules to uniformly coat the surfaces of the granules with the thermosetting resin. A general-purpose mixer such as a pump blender or a Henschel type mixer can be used for this, but when using foam particles such as the expanded perlite mentioned above, a mixer with rotary blades like this can be used. Since there is a risk that the particles may be destroyed if a mixer is used, in the present invention, it is particularly preferable to use an oscillating type mixer in which the mixing container itself oscillates.

A heated gas such as water vapor, heated air, or inert gas is pressurized into the mixture coating thus obtained, and is passed through the mixture to harden the thermosetting resin coating the granular particles and create a porous structure. The following two methods are suitably employed to form the material. The first method is to fill a mixed coating into a mold with a large number of ventilation holes, and press a heated gas into or through the mold to cure the thermosetting resin. As a device for pressurizing heated gas, a general-purpose autoclave, retort forming machine, or foam molding machine is appropriately used, and generally heated gas is introduced from the outside and molded by maintaining it at a constant pressure for a certain period of time. In addition, as a device for passing heated gas into the mixed coating, for example, as shown in Fig. 1, a mold with a large number of ventilation holes is sandwiched between molding cans, and the heated gas is passed through the ventilation holes. is appropriate (steam forming method). However, this method of passing heated gas may be unsuitable for materials such as unsaturated polyester resins that contain a large amount of reactive volatile materials (for example, styrene monomer) because they may evaporate.

Note that the first method using this mold is particularly suitable for obtaining complex molded products.

A second method is to preform the mixed coating and pressurize heated gas into the preform. Most of the thermosetting resins used in the present invention are relatively viscous liquids, and the granules coated with them retain their own shape, so molded products with simple shapes such as flat plates and blocks are possible. In order to obtain this, it is not necessarily necessary to use a mold as in the first method; for example, a frame is set up on an iron plate, the mixed coating is poured into the frame, preformed, and the frame is attached. Tama,
Alternatively, it can be removed and placed in the above-mentioned molding can, and heated gas is introduced into the molding can to maintain the pressure, thereby molding by pressurizing the heated gas into the mixed coating.

The pressure of the heated gas used in the present invention is not particularly limited;
Curing is possible even at a pressure as low as kg/Cd gauge.

Increasing the pressure of the heated gas is effective in increasing the molding speed, but the pressure resistance of the molded can as a whole becomes a problem, so it is better to mold the can under an appropriate pressure. If you use steam, you can use either saturated steam or superheated steam.

(Effects of the present invention) When the method of the present invention is used to combine granules to form a porous material, the molding time is greatly shortened compared to the conventional method of heating from the outside. be able to. This is because in the conventional method, the mixed coating must be heated to the inside by conductive heat from the outside, whereas in the method of the present invention, the high-temperature i-body is directly press-fitted into the mixed coating. This effect is particularly noticeable when using materials that inherently have poor thermal conductivity, such as foamed particles such as expanded ξ-lite.

As described above, the method of the present invention can effectively heat-form a mixed coating in a short period of time, which not only leads to energy savings, but also allows products of consistent quality to be easily produced.

Additionally, when external heating is used as in the conventional method, volatile substances (reactive monomers, low molecular weight components, etc.) contained in the thermosetting resin evaporate, significantly worsening the working environment. On the other hand, in the method of the present invention, the thermosetting resin is reacted and cured and is carried out in a closed container, so there is almost no such inconvenience.

Next, examples of the present invention will be described, but the present invention is not limited by the following examples.

Example 1 Epoxy resin (trade name [EPOMIKvR-130Rj manufactured by Sansampata Petrochemical Co., Ltd. 20g and Hardening agent (product name: EPOM
IK VQ-5J (manufactured by Mitsui Petrochemicals, Inc.) 8 g of the formulation was mixed in a beaker to obtain a mixture in which the surfaces of expanded perlite particles were uniformly coated with the epoxy resin formulation.

Next, this mixture is added to a depth of 3Cf with a large number of slits.
The mold was filled into a mold of rL, and this mold was loaded into a polystyrene foam molding can, water vapor was introduced into the molding can, and the pressure was maintained at a pressure of 1 kg/cal-di for 2 minutes.

When the molded product was removed from the mold after being depressurized and cooled, a porous material in which pearlite particles were firmly bonded was obtained.

Example 2 Expanded pearlite (trade name: "
Fuyolite No. 1 (manufactured by Fuyolite Co., Ltd.) 11, 20 g of modified LPB face (thermosetting resin prepared by blending acrylic acid-modified liquid polybutadiene with styrene monomer and naphthenic acid co/2) and 0.0 g of curing agent (methyl ethyl ketone peroxide). 2g of the formulation was prepared in the same manner as in Example 1.

This mixture was filled into a preform mold having an iron frame with a depth of 3 cr/L placed on an iron plate, and after leveling the upper part, the iron plate was removed, and a preform was obtained without deforming the mixture.

Next, this molded body was placed on an iron plate and loaded into the same molding can as in Example 1, water vapor was introduced, and the pressure was maintained at a pressure of 0.5 kg/J gauge for 2 minutes.

After depressurizing and cooling, the molded product is taken out from the mold ・ξ
- A porous material in which light viscous was firmly bonded was obtained.

Example 3 The same mixture as in Example 1 was filled into the same mold as in Example 1, this was loaded into a molding can as shown in Fig. 1, water vapor was introduced into the upper part, and water vapor was passed through the slits of the mold. Steam was passed for a minute.

When the molded product was taken out after cooling, a porous material similar to that of Example 1 was obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a steam-passing molding method that is an embodiment of the present invention. Code 1 Molding can 2 Molding mold 3 Steam population 4 Steam outlet patent applicant Japan Petrochemical Co., Ltd. Agent Patent attorney

Claims (6)

[Claims] (1) In a method of forming a porous material by combining countless granules, a thermosetting resin is mixed with the granules, the surface of the granules is coated with the thermosetting resin, and the inside of the mixed coating is A method for molding a porous material, which comprises curing the thermosetting resin by pressurizing or passing heated gas through the material. (2) The mixed coating is filled into a mold provided with ventilation holes, and heated gas is forced into or passed through the mold to form the mixture. Method of forming porous materials. (3) A method for forming a porous material according to claim 1, characterized in that after the mixed coating is preformed, heated gas is forced into or passed through the preform. (4) The method for forming a porous material according to any one of claims 1 to 3, wherein the heated gas is water vapor. (5) The method for forming a porous material according to any one of claims 1 to 4, wherein the granules are expanded pearlite. (6) Claim 1, wherein the thermosetting resin is an epoxy resin, liquid polybutadiene, or a modified product thereof.
A method for forming a porous material according to any one of Items 5 to 5.