JP2536466B2 - Siliceous paste - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to siliceous pastes. The paste of the present invention is composed of microparticles of a liquid-containing gel of silicic acid or colloidal silica, and is suitably used as a wallpaper adhesive, an adhesive for corrugated corrugators, and the like.

[0002]

2. Description of the Related Art Pasts of organic polymer materials such as carboxymethyl cellulose, starch and polyvinyl alcohol have been known, but siliceous pastes have not been known.

[0003]

The paste of an organic polymer substance is used as an adhesive between various materials, but it is essentially insufficient in water resistance and flame retardancy. It is an object of the present invention to provide an inorganic paste having a property of exhibiting an adhesive force or a bonding force and having essentially high water resistance and flame retardancy.

[0004]

The paste according to the present invention is made of Si
Consists of particles with a particle size of 300 microns or less produced by crushing siliceous jelly having an O ₂ content of 1 to 60% by weight, and a liquid interposed between these particles in an amount sufficient to prevent the binding of these particles. . This paste is usually about 50 cps ~
It has a viscosity of 1 million cps and exhibits thixotropic properties.

The particles that make up the paste of the present invention are:
It can be confirmed by observation with an optical microscope and a liquid phase sedimentation method. Larger particles are suitable for observation by optical microscopy, and smaller particles are suitable for observation by liquid phase sedimentation. The observation by the liquid phase sedimentation method can be preferably carried out by introducing the paste into water, subjecting the water to ultrasonic waves to sufficiently disperse the constituent particles of the paste in water, and then measuring.

Immediately after production of the paste, the size of the particles constituting the paste is about 300 microns or less, usually
Although it is about 1 to 100 microns, when the paste is left to stand after manufacturing, observing the paste with an optical microscope reveals that the crushed particles are aggregated with their grain boundaries in contact with each other.
Particles larger than micron may be present in the paste. The paste of the present invention may be a mixture of such particle groups.

The liquid which is present between the particles in the paste and prevents the particles from binding to each other is preferably the same as the liquid medium of jelly. Usually, this liquid
A small amount of liquid released from the jelly is sufficient when crushing into particles having a size of 300 microns or less, but a small amount of liquid added before or during the crushing of the jelly may be used. Strictly speaking, the particles produced by crushing cannot be said to have the same composition as the jelly before crushing because the amount of liquid released during crushing is removed from the jelly, but this released liquid is Since the amount of is small, it is substantially the same as the jelly before crushing. Like the jelly before crushing,
Particles generated by crushing do not absorb liquid,
Therefore, the particles are non-swelling, but have the property of releasing the liquid inside by drying.

The jelly used to make the pastes of the present invention is readily obtained by known methods from various solutions or sols containing SiO ₂ . The medium of this solution or sol may be water, an organic solvent or a mixture thereof, but a preferred jelly is obtained from a solution in water. A siliceous aqueous jelly which is a preferred example is various acids or salts in an aqueous solution of a water-soluble silicate such as water glass, for example, sulfuric acid, hydrochloric acid,
Nitric acid, acetic acid, citric acid, sodium chloride, a method of adding magnesium sulfate or the like, a method of gelling an aqueous solution of silicic acid or an oligomer thereof obtained by decationizing an aqueous solution of a water-soluble silicate such as water glass, or further The silica sol can be obtained by a known method such as gelation.

The jelly preferably contains 1 to 60% by weight of SiO ₂ . The acid, salt or base added during the preparation of the jelly may be contained in the jelly as it is, but may be removed from the jelly by washing the jelly with water. And, as long as the object of the present invention is achieved, the jelly may contain optional components such as pigments.

The paste of the present invention is obtained by crushing a jelly as described above by applying a physical external force sufficient to cause destruction of the jelly. This crush is 300
It must be able to be subdivided into jelly particles of submicron size. The crushing that results in such subdivision is
For example, it can be carried out by applying strong stirring such as a homogenizer to the jelly at room temperature. This vigorous stirring is continued until the obtained paste has the above viscosity.

As long as the object of the present invention is achieved, the paste of the present invention may contain arbitrary components such as water and a surfactant, in addition to the above-mentioned finely divided jelly particles. The content of such an optional component is a method of mixing the paste and the optional component, a method of crushing the jelly after adding the optional component to the jelly before crushing in the crushing step of the jelly, or during crushing of the jelly. Can be carried out by the method of adding this optional component to.

The thixotropic properties of the paste of the present invention can be maintained for several minutes to several months after its production. And the higher the SiO ₂ concentration in the jelly,
Further, the smaller the SiO ₂ particle size before the jelly preparation, the shorter the fluidity retention time of the obtained paste tends to be.

[0013]

The paste of the present invention cannot be obtained by applying a gentle external force such as normal stirring or applying ultrasonic vibration to the jelly as described above. Further, even if a large amount of liquid, for example, water is added to the above jelly and the mixture is stirred by a homogenizer, the paste of the present invention cannot be obtained. However, it is surprising that the paste of the present invention can be obtained by directly adding the homogenizer stirring to the jelly as described above.

Probably, since the jelly is an elastic body, when the external force applied only causes the jelly to elastically deform, the paste of the present invention cannot be obtained, and a strong external force enough to crush the jelly is obtained. It is believed that the paste of the present invention is obtained when is added and when this crushing results in particle fragmentation. Maintaining the fluidity of this paste, in which the subdivided particles do not combine and return to the jelly again, for example, an aqueous jelly consisting of a siloxane bond having a three-dimensional network structure containing water is used as described above. When crushing occurs, some of the water taken up inside the jelly is released, and the water intervenes around the particles generated by this crushing so as to prevent the recombination of these particles, It is considered that this is because the relative movement is possible. When the aggregates are formed when the paste is left to stand, the apparent fluidity of the paste is lost, but it does not return to the jelly before subdivision, and when the paste is stirred again, the fluidity of the paste is reduced. It is considered that the recovery is also due to the presence of water in the grain boundaries of the fragmented particles.

However, 300 particles are produced by the above crushing.
When it is larger than micron, it does not have the above-mentioned properties of the paste of the present invention. In addition, the paste of the present invention can be obtained by crushing such jelly both when the SiO ₂ concentration of the crushed jelly is 1% by weight or less and when it is 60% by weight or more. I can't.

[0016]

【Example】

(A) Preparation of jelly Jellies G ₁ , G ₂ , G ₃ and G ₄ were prepared as follows. G ₁ : An aqueous solution of silicic acid and its oligomer (SiO ₂ concentration 3.6% by weight, pH about 3) obtained by decationizing a commercially available aqueous solution of sodium water glass is left as it is at room temperature.

G ₂ : Commercially available alkaline aqueous silica sol (Si
By adding sulfuric acid (O ₂ concentration 30% by weight), pH 6.5, Si
A sol having an O ₂ content of 28.5% by weight is prepared and left at room temperature. G ₃ : Commercially available alkaline aqueous silica sol (SiO ₂ concentration 50 weight
%) With sulfuric acid to form a sol having a pH of 6.5 and a SiO ₂ content of 48% by weight, and allowed to stand at room temperature.

G ₄ : Sulfuric acid is added to a commercially available JIS No. 3 water glass to obtain a jelly having a SiO ₂ content of 10% by weight. (B) Preparation of paste By using a homogenizer to crush each of the jellies G _{1 to} G ₄ prepared in (a) under the conditions shown in Table 1, paste Nos. 1 to 1 shown in Table 1 Got 14.

(C) Viscosity measurement The paste Nos. 1 to 14 obtained above were measured with a B-type viscometer at a spindle speed of 0.6 rpm and a temperature of 23 ° C., and the viscosity observed in Table 1 was observed. Was done. (D) Measurement of particle size To the paste No. 2 obtained above, 10 weight times of pure water was added, gently stirred, and then ultrasonically vibrated for 5 minutes to sufficiently disperse. The particle size of this dispersion was measured using an optical microscope and a centrifugal sedimentation measuring instrument.
The particle size was 300 microns. Large particles were measured by an optical microscope, and small particles were measured by a centrifugal sedimentation method.

Table 1 Paste Jelly Homogenizer Conditions Viscosity No. No. Rotational speed (rpm) Crushing time (min) (cps) 1 G ₁ 3000 5 650000 2 G ₁ 5000 5 740000 3 G ₁ 5000 10 630000 4 G ₁ 10000 5 870000 5 G ₂ 3000 5 430 6 G ₂ 5000 5 410 7 G ₂ 5000 10 300 8 G ₂ 10000 5 210 9 G ₃ 3000 5 1300 10 G ₃ 5000 5 580 11 G ₃ 5000 10 380 12 G ₃ 10000 5 60 13 G ₄ 5000 5 30000 14 G ₄ 10000 10 100000 The pastes Nos. 1 to 14 gradually lost their fluidity when stored at room temperature under airtightness, but showed fluidity again by stirring.

The above No. 2 paste is applied to wood free paper,
On top of that, another piece of high quality paper is stuck and crimped
After drying at 100 ° C. for 10 minutes, a well-bonded laminated paper was obtained.

[0022]

According to the present invention, by subdividing the siliceous jelly, a siliceous paste having a thixotropic property can be obtained very easily. This paste is used for applications where carboxymethyl cellulose (CMC) or silica sol is used, such as thickener, adhesive, dispersant, emulsifier, stabilizer, coating agent, adhesive, sealant, friction increasing agent, fluidizing agent. It can be used in a wide range of applications such as agents.

Continuation of front page (56) References JP-A-60-108314 (JP, A)

Claims (1)

(57) [Claims] 1. Particles having a particle size of 300 μm or less produced by crushing a siliceous jelly having a SiO ₂ content of 1 to 60% by weight, and an intervening amount between these particles in an amount sufficient to prevent the binding of these particles. A siliceous paste consisting of a liquid to be treated.