JPS5915110B2 - Inorganic rigid foam and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inorganic foam-like article, and more particularly to a dry, rigid foam composed of lamellae of the mineral vermiculite and having a cellular structure or texture.

The gist of the first invention is to use dry rigid foam having a cellular structure.
), and the walls of the cells in the cellular structure of this foam, i.e., the cells, are formed of lamellae of vermiculite that are adhered to each other by mutual attraction, and The lamella of is 0.5
It consists in a dry, rigid foam composed of lamellae of vermiculite, characterized by platelets with a thickness of less than a micron.

Vermiculite is a type of phyllosilicate mineral (i.e., a mineral with a layered structure).

After vermiculite is swollen by the action of an aqueous salt solution, it is formed into extremely thin lamellae (l) by mechanical action.
amella) or can be divided into convex platelets,
That is, it can be delaminated.

Other phyllosilicate minerals, such as hydrobiotite or chlorinated vermiculite, can also undergo exfoliation in the same or similar manner, since their majority consists of vermiculite layers.

Minerals containing these vermiculite layers also form lamellae (hereinafter sometimes simply referred to as lamellae) and are therefore included within the scope of the present invention.

It is preferred to use lamellae of vermiculite itself for forming the foam-like dry rigid articles of the present invention.

According to a preferred embodiment of the invention, the walls in the cellular structure of the rigid foam of the invention are composed of individual vermiculite lamellae that overlap and adhere together by mutual attraction. is preferred.

The cellular structure in the foam-like rigid foam of the present invention is
It extends continuously and substantially uniformly in all directions throughout the foam formed.

Since the overlapping vermiculite lamellae in the structure form the boundary walls of each cell in the cellular structure, the individual lamellae in the structure as a whole are It extends at all different angles and exists in all possible orientations.

In this respect, the rigid foams of the present invention can therefore be distinguished from the known thermally delaminated vermiculite granules produced conventionally.

As conventionally known vermiculite granules delaminated by heating, low-density vermiculite granules are manufactured, but in this case, before the heating delamination treatment, the vermiculite granules were composed of individual independent particles. Inside each individual vermiculite granule, the layers of vermiculite are subjected to forces that cause them to separate from each other during heat treatment.
These layers remain substantially parallel to each other, and since the structure in such a state exists only locally within each granule of vermiculite, the structure between each granule of vermiculite However, it has not expanded to the point where it exhibits a continuous delaminated structure.

Such known low density vermiculite foams are not included within the scope of the present invention.

The individual vermiculite lamellae (lamellae may also be referred to as platelets or flakes) forming the rigid foam of the present invention are preferably less than 0.051 IXn,
In particular, the lamella has a thickness of less than 0.005 μm (corresponding to the smallest three-dimensional dimension of the lamella), and a length that is at least 100 times larger, preferably 100 times larger than the dimension dimension in the thickness direction. Or have a dimension in the width direction.

The density of the rigid foam of the present invention is in the range of 0.59 firJ2 or less, usually 0.15 g/TLl or less,
Especially for lightweight foams, the density should be set to 0.01V-
It can be made reasonably low.

The density of the foam of the invention can be determined in several ways, for example by introducing different amounts of gas into the suspension of vermiculite lamellae used during its manufacture or by varying the solids content in the suspension. By doing so, it can be varied.

The solids content in suspensions of vermiculite lamellae when producing low-density foams is 5-20 w/w%
is suitable, but the solids content can be increased to 30% w/w or more when production of higher density foams is desired.

To produce the rigid foams of the present invention, generally a suspension of vermiculite lamellae of the desired symmension dimensions dispersed in a liquid medium, preferably an aqueous liquid medium, is prepared; contains gas to form bubbles (froth
) and removing the liquid medium from the foam.

The gist of the second invention is to generate gas in the presence of a surfactant to form bubbles in a suspension of vermiculite lamellae dispersed in a liquid medium; A method for producing a dry rigid foam of vermiculite lamellae by removing a liquid medium from a suspension of vermiculite lamellae, characterized in that:

Swelling and delamination of vermiculite by chemical means to obtain an aqueous suspension of vermiculite lamellae is described in several publications, such as British Patent No. 1,016,3.
No. 85, No. 1,076,786 and No. 1,119
, No. 305, “Mi cron” 7.247
(1976) (Balmeister and Byrne), and these operations can be applied to the process of the present invention.

However, in order to produce the foam of the present invention, a surfactant or a foaming agent is first added to a suspension of vermiculite lamellae, and then a gas is blown into the suspension to create foam (fr).
oth) is preferably formed.

"One bubble here" means the expanded foam (foa) of the entire suspension.
m difference shall be included.

The surfactant or foaming agent is preferably one that can penetrate into the internal structure of the vermiculite mineral, swell the vermiculite mineral, and cause delamination.

In particular, it is preferable to use cationic organic salts that undergo ion exchange with the cations present in the layer of vermiculite.

Particularly preferred cationic surfactants are those with hydrocarbon-substituted ammonium groups.

For example, 1 to 4 hydrogen atoms of an ammonium cation,
It may be substituted with an alkyl group, an aryl group, an alicyclic group or a heterocyclic group.

Examples of preferred cationic organic salts include the following.

n-butylammonium chloride, isobutylammonium chloride, isoamylammonium chloride, cetylpyridinium bromide, -fzf-trimethylammonium)゛romite,
2-ethylhexylammonium chloride, dodecylammonium chloride, lysine monohydrochloride, ornithine type polypeptides.

Other foaming agents or foaming surfactants may also be used as additives to suspensions of vermiculite lamellae, as adjuvants for other swellings, e.g. alkali metal chlorides, or as cationic salts, e.g. long-chain Can be used in combination with aliphatic alcohols (e.g. dicetyl alcohol), alkyl sulfate salts (e.g. nilauryl sulfate sodium salt), N-acyl sarcosinates and long chain aliphatic amine oxides (e.g. nioleyldimethylamine N-oxide) .

Another type of foaming agent which is advantageously used as an additive to suspensions of vermiculite lamellae is protein-type foaming agents, such as water-soluble proteins such as albumin or gelatin, or hydrolyzed soy protein and hydrolyzed Surfactants in the form of water-solubilized protein derivatives such as blood or feather proteins.

The liquid medium contained in the suspension of vermiculite lamellae, when it is aqueous, may contain water-miscible organic liquids, such as lower alcohols or acetone.

Alternatively, foam may be produced in a non-aqueous medium using suitably modified vermiculite as described in GB 1.076,786.

Does the step of generating gas in suspension in the method of the present invention involve generating or releasing gas or vapor in the suspension of vermiculite lamellae? It is done by

Preferred gases or vapors are those that are substantially inert to the aqueous suspension, such as air, nitrogen, argon, carbon dioxide, hydrocarbons, chlorinated carbons, fluorinated carbons, and chlorinated carbons.

It is more expedient to introduce the gas by mechanically trapping it in the suspension, for example by rapid stirring or bubbling of the suspension.

Alternatively, the suspension can be heated rapidly and the bubbles created by the introduction or generation of gas by the vaporization of water in the liquid or by the release of gases dissolved in the feedstock.

As used herein, "rigid foam" is a two-phase dispersion in which gas is dispersed in the form of bubbles in a solid phase composed of vermiculite lamellae, and the solid phase is substantially continuous. Vermiculite with a cell-like structure.

Small amounts of organic material may be present in this foam matrix;
Although it may be added intentionally or present inadvertently, such organic matter is not the source of the adhesive forces that maintain its cellular structure.

However, such organic substances may also have properties that usefully modify the properties of the cellular structure consisting of vermiculite lamellae.

In the method of the invention, when water is removed from an aqueous dispersion of vermiculite lamellae, the lamellae are brought together into a coherent film.
form a film).

Therefore, most or all of the mechanical strength of the walls of the cells of the cellular structure of the present invention comes from the adhesion of the vermiculite lamellae to each other when water is removed.

The foam obtained by the method of the invention is not brittle, i.e. it deforms (d) without collapsing when subjected to pressure.
eform) L/Uru.

The vermiculite rigid foam of the present invention is a useful heat-resistant insulation material that can be injected as a foam filler for cavities and voids, or used as a cladding for the exterior of objects such as woodwork or steelwork, and any In both cases, the vermiculite rigid foam of the invention can act inter alia as a fire-resistant layer.

The rigid vermiculite foam of the present invention may be manufactured as a slab material for subsequent processing or further lamination.

Sand inch structures in which vermiculite rigid foams according to the invention are optionally sandwiched between sheets of, for example, plywood, paper, asbestos, mica, plastic, or between sheets of vermiculite, make useful decorative structural panels and The rigid vermiculite foam of the invention can also be sandwiched between sheets of plasterboard or thermosetting resins, such as melamine resins.

These above-mentioned structures result in architectural fire-resistant and/or acoustical panels, which can be maintained without decomposition at temperatures of about 1000°C.

The vermiculite rigid foam sheets of the present invention can be applied as facings to polyurethane foam panels by conventional lamination techniques to improve the fire resistance of the polyurethane foam core.

The foam produced in the course of the method of the invention, i.e. the vermiculite lamellar suspension into which gas has been introduced but which has not yet been subjected to a drying step to remove the liquid medium, can be used to form already formed vermiculite structures, e.g. It is convenient to join together two sheets or slabs of foam in the dry state, so that several sheets can be joined together to create larger structures.

Similarly, it is also possible to bond vermiculite granules exfoliated by heating together by means of the foam,
In this way, a composite material can be formed in which the rigid foam of the present invention is interposed in the form of a binder that connects the vermiculite granules exfoliated by heating.

For certain applications, the vermiculite of the present invention
Lamellar rigid foams may require water-resistant treatment, for example water stabilization treatment with ammonia (see Japanese Patent Application No. 1983-39092).

The invention will be illustrated by the following examples.

Example 1 Vermiculite ore from South Africa (Mandova 1
(known as Micron variety) was refluxed in a saturated saline solution 51 for 30 minutes.

Excess saline was decanted and the vermiculite was washed in 54 g of distilled water.

Next, this solid vermiculite was washed with a Buchner P.
Washed 5 times with 5 portions of distilled water.

The wet cake of vermiculite thus obtained was returned to the reflux vessel used above and refluxed for 2 hours with a solution of 1.25 mol of butylammonium chloride made up to 51% with distilled water.

After this reflux treatment, the above-mentioned washing treatment with water was carried out again, during which the vermiculite was removed by about 60% of its initial volume.
It quickly expanded to double its size.

- After standing overnight, the supernatant was decanted and the swollen vermiculite of about 61 was divided into about 31 portions, and each portion was made up to 41 with distilled water in a large beaker.

The suspension of vermiculite thus obtained in the beaker is then mixed by inserting a rotary vane mixer into the beaker.
Shear was applied for one hour with rotation at 6+50 orpm.

The suspension was maintained near room temperature by spraying cold water onto the outer wall of the beaker.

During this shear treatment, air is trapped in the suspension of vermiculite lamellae and bubbles (frots) are formed on the surface of the suspension.
h) occurred.

When the suspension was allowed to stand for 30 minutes, the height of the foam increased and about 600 ml of foam was immediately removed from the suspension in the round beaker.

The foam was placed in a mold and dried at 60° C. in a well-ventilated oven.

0, 08 j! generated in this way! /rfLl
The dried rigid foam of vermiculite lamellae with a density of .

The foam conformed to the shape of the mold and had a skin of vermiculite on the surface.

When the suspension of vermiculite lamellae remaining in the beaker was again stirred at high speed for 60 minutes and then allowed to stand for 30 minutes, new bubbles were generated.

This operation was repeated several times, thereby obtaining several batches of foam from the same suspension.

These are combined together, transferred to a mold and dried in a ventilated oven as above to form o, o s g7vti and cells (small air chambers c) made from vermiculite lamellae.
ell) A solid foam with an average diameter of 0.7 mrn was obtained.

Example 2 Vermiculite ore from North Africa
The pulverized product of eA4) was refluxed in a saturated saline solution for 30 minutes, and thoroughly washed several times with distilled water.

Next, the vermiculite particles were treated in an aqueous n-butylammonium chloride solution under reflux conditions for 2 hours, and then thoroughly washed with distilled water.

During this second washing, which conveniently lasts from several minutes to several hours, the vermiculite particles
It swells significantly reaching approximately 6 times the initial wet volume.

The swollen particles were used as a sample of expanded vermiculite.

Water was removed from the above aqueous suspension of swollen vermiculite by filtration to adjust the solid content of vermiculite to 10% solids to liquid water 90 parts (weight ratio).

This prepared suspension was mechanically kneaded for 10 minutes in a high shear mixer (manufactured by Greav 63) with blades rotatable at 6,500 rpm.

During this operation, air was trapped in the suspension and a bubble several inches high formed on the suspension when the rotor was stopped and the suspension was allowed to stand for 5 minutes.

This foam was immediately removed with a knife and applied onto a tray.

The tray was placed in a well-passed oven at approximately 60°C and the water was removed from the foam by evaporation.

This water removal was optionally aided by a blower or suction device inside the furnace.

When the above foam is dry, add it to 0.1 g/ml.
It could be removed from the tray as a solid cellular structured vermiculite lamellar foam with a density of:

Example 3 Vermiculite Zonolite4 used in Example 2
A sample of 4 was processed as in Example 2 and the suspension was
Kneaded for a minute.

The density of the foam obtained in the dry layer is 0.035 g/Tn
1, and the average cell diameter was 0.5 mm.

Example 4 South African vermiculite was swollen as described in the first part of Example 1.

The solid content of the swollen vermiculite suspension is 20w/w.
%, then stir until homogeneous, 20.00
The sample was passed once through a mill (rotor-in-stator type mill) rotating at an rpm.

Air was metered into the suspension at a rate of 101/min before entering the shear zone of the mill.

The entire suspension turns into a thick foam, and when left overnight,
It separated into a lower liquid layer containing relatively large sized vermiculite particles and an upper layer of bubbles of wet vermiculite lamellar suspension.

The foam, which was found to be stable in wet conditions for several weeks, was collected and dried in a full-mesh mold in a well-ventilated 80° C. oven.

A vermiculite lamellar foam slab having dimensions of 12 inches x 12 inches x 2 inches is obtained;
This product was found to have the following characteristics.

Density 0.12g/rule Compressive strength 0.11MNm ”-2
Thermal conductivity 0.060Wm-'K"
Example 5 3 kg of American vermiculite was swollen in the same manner as described in the first part of Example 2.Closed cell rate 12% Average cell diameter 1.5.

The swollen vermiculite was then divided into nine batches and each batch was milled in the Greaves mill for 45 minutes to create a suspension of delaminated vermiculite.

These nine batches were then combined to give a suspension of 50
The thick particles of vermiculite were removed by passing it through a ltm sieve.

The sieved suspension thus obtained contained approximately 5 wt% solids.

This was placed in a large heated tray to evaporate the water from the suspension and increase its solids content to 20 parts.

Air was then incorporated into the thick suspension using a cooking mixer with a whisk attachment.

The volume of the suspension almost doubled and the entire suspension gave rise to a moist foam containing small air bubbles.

Spread this foam on a heated tray and let it dry overnight.
A board-shaped foam constructed of vermiculite lamellae was obtained having dimensions of 6 feet by 4 feet by 1/4 inch.

This dried foam had the following properties:

Density 0.12g/yd Compressive strength 0.30 MNm-2 Thermal conductivity
0.060 Wm-1 to 1 independent cell rate 4
1% Cell average diameter 0.2 mrn Example 6 3 kg of South African vermiculite was swollen as described in the first part of Example 1.

After the swelling was completed, the supernatant water was decanted and the swollen vermiculite was kneaded in 750 ml portions for 10 minutes using a household juicer.

A thick but pourable suspension is obtained, which
% (w/w) solids content.

This suspension was foamed in the cooking mixer of Example 5.

The wet foam obtained as above was then heated to 90°C.
Dry in the oven overnight and measure 24 inches x 12 inches x
A 1/4 inch slab was obtained.

Several of these slabs were laminated with the wet foam sandwiched between them to form thick slabs measuring 12 inches by 12 inches by 72 inches and dried in an oven.

The measured physical properties of this thick slab were as follows.

Density 0.0797m1゜ Compressive strength 0.05 MNm-2 Thermal conductivity
0.048Wm K-independent cell rate 6% Average cell diameter 0.5 mrn Example 7 Non-foamed suspension of American vermiculite (2
0% w/w solids content) was made as in Example 5.

In this case the suspension was not bubbled with air, but was placed in an oven at 140° C. for 3 hours to rapidly generate water vapor.

This resulted in a dry vermiculite lamellar foam with a density of 0.109/1 rLl.

Example 8 A suspension of 170 g of South African vermiculite was prepared by the method of Example 5.

The solids content was adjusted to 13% w/w and then placed in a pressurizable aerosol container.

A mixture of 18 g dichlorodifluoromethane and 12 g dichlorotetrafluoroethane was forced into the aerosol container under pressure and mixed with the vermiculite paste contained therein.

When the spray nozzle of the aerosol container was activated, a moist foam of a suspension of vermiculite lamellae was ejected and this foam was applied to the tray.

This was dried in air for 24 hours. The thus obtained rigid foam of vermiculite lamellae has extremely fine pore sizes (average diameter of cells = 350 μm) and
．． It was found to have a density of 059/TILl.

Example 9 Vermiculite from South Africa (Man dova 1
water (41), manganese dichloride tetrahydrate (13 (Bi')) and concentrated hydrochloric acid (0,251
No. 111) was refluxed for 10 hours.

This was washed with water and then brought to a total volume of 2M with water.

Hydrochloric acid (751 rLl of IN solution) and hydrogen peroxide (30
After adding % solution 2A) and heating at 60° C. for 2 hours with stirring, the vermiculite expanded to the extent that it absorbed most of the liquid present.

The mixture was then cooled, filtered, washed with water, and made up to 101 with water.

The resulting suspension was divided equally into four batches, each of which was placed in 51 containers using the Greaves H5 Series.
Shearing force treatment was performed for 1 hour using a mixer (MarkllI) at 6500 rl)''.

The combined suspension was then diluted to 1M with water and fractionated through a sieve with an opening of 50 μm to obtain a suspension of vermiculite lamellae containing 2.9 wt % solids.

All water added for dilution was removed by distillation.

The solids concentration of the suspension was then brought to 20 wt% by applying heat to evaporate the water, and the mixture was cooled to combine the protein surfactant with cerol.

N1cerol trademark) was added at a concentration of 10vol% based on the weight of vermiculite solids, the mixture was divided into several portions and mixed with a cooking mixer.
Got bubbles.

The rigid foam of vermiculite lamella dried in a 90°C oven with good ventilation was 0.1g/1rLl.
It had a density of

Example 10 When South African vermiculite (lky) was refluxed in a 20% w/w lithium chloride solution for 2 hours, rinsed well in a Buchner furnace, and then placed in distilled water overnight, the mineral was found to have a higher concentration than the initial vermiculite mineral. An 8-fold volume expansion occurred.

This expanded vermiculite and water (Vermiculite 1
0% w/w) was kneaded for 1 hour.

Large vermiculite particles were removed by filtration through a 50 μm sieve, and the concentration of the suspension was reduced to 2 by evaporation of water.
Adjusted to 0% w/w.

A protein surfactant (commercial product N1cerol) was added at a concentration of 10vol 1% based on the weight of vermiculite,
The mixture was divided into several portions and mixed with a cooking blender to obtain foam.

The rigid foam of vermiculite lamella obtained by drying the foam in a well-ventilated oven at 90°C weighs 0.1 g/
It had a density of Ttl.

Example 11 Similar to Example 4, a dry foam of vermiculite lamellae was made using vermiculite from North America, but this one had an average cell size of 3.00 m's and a density of 0.
．． 01 g/Tll.

Example 12 A wet foam sample of the vermiculite lamellar suspension made in Example 6 was blended with heat expanded vermiculite granules.

In the resulting blend, the wet foam accounted for 34% of the total volume and the granules accounted for 66% of the total volume.

This blend was dried in an oven at 90°C.

The resulting composite structure had a density of 0.229/rul and a compressive strength of 0.12 MNm-2.

Example 13 A foam slab of dimensions 627nr/L x 135im x 4mm cut from a slab of vermiculite lamellar foam with a density of 0.1297ml made in Example 5 was placed in a heating oven at 1000°C for 10 minutes. .

Upon removal from the furnace, the slab appeared to have undergone no apparent deformation due to ignition.

The dimensions after heating were 617 x m x 134 m x 4 mm, but the density was reduced to Olo 9 g/TLl and its compressive strength was 0.22 MN m-''.

The above results indicate that the foam-like rigid article of the present invention can withstand heat well and therefore can be used as a fire-resistant material.The reason for this is that the foam-like rigid article of the present invention can be compressed even under high heat. This is because it has good dimensional stability without almost losing strength.

Claims (1)

[Claims] 1. A dry, hard foam having a cellular structure;
The cell walls of the cellular structure of this foam are formed by lamellae of vermiculite that are adhered to each other by mutual attraction, and the lamellae of vermiculite are platelets with a thickness of less than 0.5 microns. A dry, rigid foam composed of vermiculite lamellae. 2. A rigid foam according to claim 1, wherein the walls of the cellular chambers in the cellular structure are composed of individual vermiculite lamellae that adhere to each other and overlap due to mutual attraction. 3. The foamed sail according to claim 1 or 2, wherein the thickness of the vermiculite lamella is 0.05 μm or less. 4. The length or width of the vermiculite lamella is at least 100 times the thickness thereof. A rigid foam according to claim 1, 2 or 3 having dimensions. 5. The rigid foam according to claim 1, 2, 3 or 4, wherein the vermiculite lamella has a length or width dimension that is at least 1000 times the thickness of the vermiculite lamella. 6. A rigid foam according to any one of claims 1 to 5, which is formed into a continuous and substantially uniform sheet, slab or foam. Rigid foam according to any one of claims 1 to 6, having a density of 10.5 g/yrtl or less. 8. The rigid foam according to claim 7, having a density of 0.15.9/ml or less. 9. Formation of vermiculite lamellae, characterized in that in the presence of a surfactant gas is generated in a suspension of vermiculite lamellae dispersed in a liquid medium to form bubbles, and then the liquid medium is removed. Preparation of dry rigid foams of vermiculite lamellae by removal of the liquid medium from the suspension.