JP2000290452A - Mg-al-based hydrotalcite type particle powder, stabilizer for chlorine-containing resin and production of the same powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain Mg-Al-based hydrotalcite type particle powder having a large plate surface diameter and appropriate thickness, and suitable as a stabilizer for a chlorine-containing resin and to provide a method for producing the same. SOLUTION: This Mg-Al-based hydrotalcite type particle powder having 0.1-1.0 μm plate surface diameter and 0.02-0.08 μm thickness, containing 0.01-0.20 molar ratio of calcium based on the total number of moles of Mg and Al and exhibiting >=4 hr heat resistant time in the case of heating a resin sheet prepared by mixing 3 pt.wt. particle powder with 100 pts.wt. vinyl chloride resin at 180 deg.C, is a stabilizer for a chlorine-containing resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a large plate surface diameter,
An object of the present invention is to provide Mg-Al-based hydrotalcite-type particles having an appropriate thickness and suitable as a stabilizer for a chlorine-containing resin.

[0002]

2. Description of the Related Art As well known, there are various kinds of layered compounds other than clay minerals and the like. Among them, layered double hydroxides such as hydrotalcite are known.
(Ultra Hydroxide) has a structure in which various ions and molecules can be inserted between layers, and thus can exhibit an anion exchange function.

[0003] Generally, the structure of hydrotalcite is
Described in the journal of the Chemical Society of Japan, 1995 (8), pp. 622-628.
As mentioned, "[M²⁺ _1-xM³⁺ _x(OH)₂]_x ⁺[An⁻
_{x / n}・ YH₂O]_x ⁻  Where M²⁺Is Mg²⁺, Co²⁺, Ni²⁺, Zn
²⁺Divalent metal ions such as M³⁺Is Al³⁺, Fe
³⁺, Cr³⁺Trivalent metal ions such as An⁻Is OH
⁻, Cl⁻, CO₃ ^2-, SO₄ ^2-N-valent shades such as
On, x typically ranges from 0.2 to 0.33. Conclusion
The crystal structure is composed of a positively charged octahedral brucite unit.
It consists of a two-dimensional base layer in which
It has a laminated structure. "It is.

[0004] Hydrotalcite has been used for various applications utilizing its anion exchange function, for example, as an ion exchange material, an adsorbent, a deodorant and the like. In addition, it is used in a wide variety of applications such as resins, rubber stabilizers such as polyethylene, polypropylene, and chlorine-containing resins (typically, vinyl chloride resin), as well as paints, various catalysts, agricultural films, and inks. .

In recent years, environmental considerations have been demanded, and it is desired that catalysts and the like do not contain toxic metals. It can be said that the hydrotalcite-type particle powder which is also excellent can meet such expectations.

[0006] In particular, since among the hydrotalcite-type particles, Mg 2 ⁺ as the divalent metal ^ion, Mg-Al-based hydrotalcite-type particles having Al ³⁺ as the trivalent metal ion is stable, It is the one that has received the most attention. Examples of the hydrotalcite-type particle powder include an iron-based hydrotalcite-type particle powder (Japanese Patent Application Laid-Open No. 9-227127). However, since it has iron, it is colored when kneaded into a resin. It is difficult to say that the heat resistance is sufficient when used as a stabilizer for a chlorine-containing resin as compared with a Mg-Al-based hydrotalcite-type particle powder.

As a method for producing hydrotalcite, an aqueous metal salt solution containing a divalent metal ion and a trivalent metal ion constituting a basic layer and a carbonate aqueous solution containing a carbonate ion constituting an intermediate layer are mixed. In general, a method of controlling the temperature, pH value, and the like to obtain by coprecipitation reaction is used. In addition to the reaction under normal pressure, a method is also known in which the reaction is obtained by a hydrothermal reaction using an autoclave.

Conventionally, as a hydrotalcite type particle powder for kneading resin, a particle powder having a large plate surface diameter and an appropriate thickness has been required in consideration of dispersibility at the time of kneading resin. To produce hydrotalcite-type particles having a large plate surface diameter, special reaction conditions such as hydrothermal synthesis are required.

When hydrotalcite-type particle powder is used as a stabilizer for a resin or rubber containing chlorine such as a vinyl chloride resin, in order to obtain a resin or rubber product having excellent heat resistance, it is necessary to use a resin or rubber. It is required to be sufficiently dispersed and to have a higher ability to capture chloride ions.

[0010]

SUMMARY OF THE INVENTION Mg, which has a large plate surface diameter and an appropriate thickness, is suitable as a stabilizer for chlorine-containing resin.
-Al-based hydrotalcite-type particle powders are the most demanded at present.
g-Al-based hydrotalcite-type particles have not yet been obtained.

That is, in the conventional method using a coprecipitation reaction, hydrotalcite-type particles having a large plate surface diameter cannot be obtained, and under special reaction conditions such as hydrothermal synthesis, a large plate surface diameter cannot be obtained. Although hydrotalcite-type particle powder can be obtained, the heat resistance of a chlorine-containing resin using the particle powder as a stabilizer is not sufficient.

An object of the present invention is to obtain Mg-Al-based hydrotalcite-type particles having a large plate surface diameter and an appropriate thickness and suitable as a stabilizer for a chlorine-containing resin.

[0013]

The above technical object can be achieved by the present invention as described below.

That is, according to the present invention, the plate surface diameter is 0.1 to 1.0.
μm, the thickness is 0.02 to 0.08 μm,
The molar ratio of calcium to the total number of moles of Mg and Al
Mg-Al based hydride containing 0.01 to 0.20
Rotalcite type particle powder, which is measured by the following method.
The heat resistance time measured by the standard method is 4 hours or more.
Mg-Al based hydrotalcite-type particle powder
(Invention 1). Hydrotalcite-type particle powder in vinyl chloride resin
And additives are mixed in the following composition ratio, and the resulting mixture 5
0 g is kneaded using a hot roll, and the kneaded sheet is kneaded.
Obtained. The kneading conditions were as follows: kneading temperature 155 ° C, roll
The gap is 0.75 mm and the kneading time is 3 min. Hydrotalcite-type particle powder: 3 parts by weight, vinyl chloride resin (degree of polymerization: 1300) (trade name: TK-1300, manufactured by Shin-Etsu Chemical): 100 parts by weight, diethylhexyl phthalate (DOP, manufactured by Daihachi Chemical): 50 Parts by weight, calcium stearate (primary reagent): 2 parts by weight, zinc stearate (primary reagent): 0.4 parts by weight, 1,3 diphenyl-1,3 propanedione (primary reagent): 0.2 parts by weight, Diethyl phosphate (primary reagent): 0.5 parts by weight. The obtained kneaded sheet is subjected to pressure treatment with a hot press,
Sheet pieces (thickness 1.5 mm) were prepared. Pressurization condition is
Press temperature 160 ° C, press pressure 100kg / cm ²,
Less time 1 minute, press gap 1.5mm, processing amount 35g
is there. The obtained sheet piece (20 mm × 20 mm) is placed in air 1
Place in an 80 ° C. oven and perform heat resistance test. Sheet pieces
The time during which the entire surface turned black is defined as the heat resistance time.

The present invention also relates to the Mg-Al of the present invention 1, wherein the particle surface is coated with at least one selected from hydroxides or oxides of silicon, higher fatty acids, organic silane compounds and rosins. A hydrotalcite-based particle powder, wherein the heat resistance time of the particle powder measured by the measuring method according to the present invention 1 is 4 hours or more.
It is an Al-based hydrotalcite-type particle powder (Invention 2).

The present invention is also a chlorine-containing resin stabilizer comprising the Mg-Al-based hydrotalcite-type particles of the present invention 1 or 2.

The present invention also relates to a method of mixing an alkaline aqueous solution containing an anion, an aqueous magnesium salt solution and an aqueous aluminum salt solution, and adding the mixed solution to the mixed solution in a molar ratio of 0.01 to 0 with respect to the total mole number of Mg and Al. .20 calcium salt aqueous solution, the pH value is 10-14,
The method for producing Mg-Al-based hydrotalcite-type particles described above, wherein the powder is aged in a temperature range of 105 ° C.

The configuration of the present invention will be described in more detail as follows.

First, the Mg-Al-based hydrotalcite-type particles according to the present invention will be described.

The Mg-Al-based hydrotalcite-type particles according to the present invention are plate-like and have a plate surface diameter of 0.1 to 0.1.
1.0 μm, and the thickness is 0.02 to 0.08 μm.

When the plate surface diameter of the Mg—Al hydrotalcite-type particles according to the present invention is less than 0.1 μm,
Dispersibility upon kneading into resin is insufficient. 1.0 μm
When it exceeds, it is difficult to produce industrially. Preferably it is 0.2 to 0.8 μm.

When the thickness of the Mg-Al-based hydrotalcite-type particles according to the present invention is less than 0.02 μm,
Dispersibility upon kneading into resin is insufficient. 0.08μ
If it exceeds m, it is difficult to produce industrially. Preferably it is 0.025 to 0.075 μm.

The Mg-Al-based hydrotalcite-type particles according to the present invention contain calcium in a molar ratio of 0.01 to 0.20 with respect to the total number of moles of Mg and Al. Preferably it is 0.03-0.15.

When the calcium content of the Mg-Al hydrotalcite-type particles according to the present invention is less than 0.01 or more than 0.20 in a molar ratio to the total number of moles of Mg and Al. Cannot sufficiently increase the plate surface diameter of the Mg-Al-based hydrotalcite-type particles.

The Mg—Al-based hydrotalcite-type particle powder according to the present invention is characterized in that
The heat resistance time when a resin sheet prepared by mixing 3 parts by weight with respect to parts by weight and heated at 180 ° C. is 4 hours or more.

When the heat resistance time is less than 4 hours, the heat resistance of the chlorine-containing resin cannot be said to be sufficient when used as a stabilizer. Preferably it is 5 hours or more. The upper limit of the heat resistance time is 10 hours.

The composition formula of the Mg-Al-based hydrotalcite-type particles according to the present invention is as follows.

[0028] _{[Mg x Ca y] · Al} z · (OH) 2 ·
An ^- _p · mH ₂ O 0.2 ≦ z / (x + z) ≦ 0.6, 0.01 ≦ y / (x + z) ≦ 0.20, x + y + z = 1 p = (2 (x + y−1) + 3z) / N, A: n-valent anion, m> 0.

The Mg / Al content ratio of the Mg—Al type hydrotalcite type particles according to the present invention is expressed as Al / Al
When (Mg + Al) = z / (x + z), z /
(X + z) is 0.2 to 0.6. When z / (x + z) is less than 0.2 (Mg: Al = 4: 1) and more than 0.6 (Mg: Al = 2: 3), the single phase of the hydrotalcite-type particles is It is difficult to obtain. z / (x +
The preferred range of z) is 0.2 to 0.56.

The sum of x, y and z is 1.

The types of anions (A ⁿ⁻ ) contained in the Mg—Al hydrotalcite-type particles according to the present invention include a hydroxyl ion (OH ⁻ ) and a carbonate ion (CO ₃ ).
^2- ) and sulfate ion (SO ₄ ^2- ), and particularly preferably carbonate ion.

The Mg—Al-based hydrotalcite-type particles according to the present invention have a tabular ratio (plate diameter / thickness) of 2 to 15%.
, More is preferably 2 to 13, BET specific surface area value is preferably 8~90m ² / g, more preferably 8~70m ² / g, the powder pH value from 9.0 to 1
0.8 is preferred, and more preferably 9.0-10.5.

The Mg-Al-based hydrotalcite-type particles according to the present invention may have a surface of silicon hydroxide or silicon oxide or silicon hydroxide and silicon oxide (hereinafter referred to as “silicon oxide”), if necessary. Silicon hydroxide, etc.), higher fatty acids, organic silane compounds, and rosins. When the Mg-Al-based hydrotalcite-type particles coated with the surface coating are used as a chlorine-containing resin stabilizer, they are more uniformly dispersed in the chlorine-containing resin, and the ability to capture chloride ions is further improved. In addition, the stability and heat resistance of the resin are further improved.

The amount of silicon hydroxide or the like coated on the particle surface of the Mg—Al hydrotalcite-type particles according to the present invention is 0 in terms of SiO _{2 with} respect to the Mg-Al hydrotalcite-type particles. It is preferably 0.05 to 50% by weight, more preferably 0.05 to 45% by weight. When the coating amount of the silicon compound is less than 0.05% by weight, the effect of coating with the silicon compound cannot be obtained. If it exceeds 50% by weight, the coating effect is saturated, so that there is no point in coating more than necessary.

The coating amount of the higher fatty acid on the surface of the Mg—Al-based hydrotalcite type particles according to the present invention is M
The content is preferably 0.2 to 20.0% by weight, more preferably 0.5 to 18.0% by weight in terms of C, based on the g-Al-based hydrotalcite-type particles. If the coating amount is less than 0.2% by weight, the effect of coating with higher fatty acids cannot be obtained. If it exceeds 20.0% by weight, the coating effect is saturated, so that there is no point in coating more than necessary.

The coating amount of the organosilane compound on the surface of the Mg-Al-based hydrotalcite-type particles according to the present invention is 0.2 to 18. It is preferably 0% by weight, more preferably 0.4 to 16.5% by weight. The coating amount is 0.
If the amount is less than 2% by weight, the effect of coating with the organic silane compound cannot be obtained. If it exceeds 18.0% by weight,
Since the coating effect is saturated, there is no point in coating more than necessary.

The coating amount of the rosin on the surface of the Mg—Al-based hydrotalcite-type particles according to the present invention is as follows.
-It is preferably 0.2 to 25.0% by weight, more preferably 0.5 to 20.0% by weight in terms of C, based on the Al-based hydrotalcite-type particle powder. 0.2% by weight coating
When it is less than the above range, the effect of covering with the rosin cannot be obtained. If it exceeds 25.0% by weight, the coating effect is saturated, so that there is no point in coating more than necessary.

The Mg-Al-based hydrotalcite-type particles surface-coated with a silicon hydroxide, a higher fatty acid, an organic silane compound, and a rosin according to the present invention are not covered with the surface-coated Mg-Al hydrotalcite-type particles according to the present invention. It has a plate surface diameter, a thickness, a plate ratio, and a BET specific surface area value that are substantially the same as those of the Mg-Al-based hydrotalcite-type particles.

The Mg—Al-based hydrotalcite-type particles having a surface pH coated with a hydroxide of silicon, a higher fatty acid, an organic silane compound, or a rosin according to the present invention have a powder pH of 7.5 to 7.5. It is preferably 9.5, more preferably 7.5 to 9.0, and the powder pH value is lower than that of the Mg-Al-based hydrotalcite-type particles according to the present invention, which are not surface-coated.

When the Mg-Al-based hydrotalcite-type particles according to the present invention are used as a vinyl chloride resin stabilizer, the mixing ratio is 100 parts by weight of the vinyl chloride resin per 100 parts by weight of the Mg-Al-based hydrotalcite-type particles. 0 powder.
It is 5 to 10 parts by weight. When the mixing ratio is less than 0.5 parts by weight, the effect of improving the heat resistance of the resin cannot be expected. When the mixing ratio is more than 10 parts by weight, the effect of improving the heat resistance is saturated, so that it is meaningful to add more than necessary. Absent. Preferably it is 1 to 8 parts by weight, more preferably 1 to 6 parts by weight.

Next, a method for producing the Mg-Al-based hydrotalcite-type particles according to the present invention will be described.

The Mg-Al-based hydrotalcite-type particles according to the present invention are obtained by mixing an alkaline aqueous solution containing anions, an aqueous magnesium salt solution and an aqueous aluminum salt solution, adding an aqueous calcium salt solution to the mixed aqueous solution,
When the H value is in the temperature range of 10 to 14 and 60 to 105 ° C.,
It can be obtained by aging for 24 hours.

As the alkaline aqueous solution containing an anion in the present invention, a mixed alkaline aqueous solution of an aqueous solution containing an anion and an aqueous alkali hydroxide solution is preferable.

As the aqueous solution containing an anion, an aqueous solution of sodium carbonate, an aqueous solution of potassium carbonate, an aqueous solution of sodium hydrogen carbonate, an aqueous solution of potassium hydrogen carbonate and the like can be used, and an aqueous solution of sodium carbonate is preferred.

As the aqueous alkali hydroxide solution, an aqueous sodium hydroxide solution is preferable.

As the aqueous magnesium salt solution in the present invention, an aqueous solution of magnesium sulfate, an aqueous solution of magnesium chloride, an aqueous solution of magnesium nitrate and the like can be used, and an aqueous solution of magnesium sulfate and an aqueous solution of magnesium chloride are preferred.

As the aluminum salt aqueous solution in the present invention, an aluminum sulfate aqueous solution, an aluminum chloride aqueous solution, an aluminum nitrate aqueous solution and the like can be used, and an aluminum sulfate aqueous solution and an aluminum chloride aqueous solution are preferable.

The order of mixing the aqueous alkali solution, the aqueous magnesium salt solution and the aqueous aluminum salt solution containing the anion is not particularly limited, and the aqueous solutions may be mixed simultaneously. Preferably, an aqueous solution obtained by previously mixing an aqueous magnesium salt solution and an aqueous aluminum salt solution is added to the aqueous alkali solution containing anions.

When each aqueous solution is added, the aqueous solution may be added at one time, may be added in two or more portions, or may be added continuously.

The calcium salt aqueous solution in the present invention is added to a mixed solution of an alkaline aqueous solution containing anions, a magnesium salt aqueous solution and an aluminum salt aqueous solution.

As the calcium salt aqueous solution in the present invention, an aqueous solution of calcium chloride, an aqueous solution of calcium nitrate and the like can be used, and an aqueous solution of calcium chloride is preferred.

The amount of the calcium salt aqueous solution to be added is 0.01 to 0.20 in molar ratio to the total number of moles of Mg and Al.
And preferably 0.03 to 0.15.

In the present invention, the concentration of the magnesium salt in the reaction solution obtained by mixing the aqueous alkali solution, the aqueous magnesium salt solution, the aqueous aluminum salt solution and the aqueous calcium salt solution containing the anion is preferably 0.1 to 1.5 mol / l. It is preferably 0.1 to 1.2 mol / l, the aluminum salt is preferably 0.03 to 1.0 mol / l, more preferably 0.04 to 0.8 mol / l, and the calcium salt is 0.001 to 1.0 mol / l. To 0.2 mol / l, more preferably 0.01 to 0.15 mol / l.
1, the anion is preferably 0.05 to 1.4 mol / l, more preferably 0.06 to 1.2 mol / l, and the alkali hydroxide aqueous solution is preferably 0.5 to 8 mol / l, more preferably Is 0.8 to 6 mol / l. The ratio of the anion to aluminum in the reaction solution is preferably 0.5 to 2.0, more preferably 0.5 to 2.0.
1.5.

The temperature during the aging reaction in the present invention is 60 to
The temperature is 105 ° C, preferably 80 to 105 ° C. 6
When the temperature is lower than 0 ° C., hydrotalcite-type particle powder is generated, but hydrotalcite-type particle powder having a large plate surface diameter cannot be obtained. If the temperature exceeds 105 ° C,
A pressure vessel such as an autoclave is required, which is not economical.

In the present invention, the pH value during the ripening reaction is 10
To 14, preferably 11 to 14. If the pH value is less than 10, a hydrotalcite-type particle powder having a large plate surface diameter and an appropriate thickness cannot be obtained.

The reaction time of the aging reaction in the present invention is 2 to 2.
24 hours is preferred. When the aging time is less than 2 hours, it is difficult to obtain a hydrotalcite-type particle powder having a large plate surface diameter and an appropriate thickness. Aging beyond 24 hours is not economical.

After the completion of the aging reaction, if washing and drying are carried out by a conventional method, Mg-Al-based hydrotalcite-type particles can be obtained.

The surface coating treatment of the Mg-Al-based hydrotalcite-type particles with a hydroxide of silicon or the like is carried out by dispersing the Mg-Al-based hydrotalcite-based particles according to the present invention in an aqueous suspension obtained by dispersing the particles. , By adding a silicon compound and adjusting the temperature of the aqueous suspension to 20 to 90 ° C. and mixing and stirring, or if necessary, after mixing and stirring, p
By adjusting the H value, the particle surface of the Mg-Al-based hydrotalcite-type particles powder is coated with silicon hydroxide or silicon oxide or silicon hydroxide and silicon oxide, , Filtered, washed with water, dried and pulverized.

As the silicon compound, No. 3 water glass, sodium orthosilicate, sodium metasilicate, colloidal silica and the like can be used. Preferred is No. 3 water glass.

The addition amount of the silicon compound is 0.05 to 50.00% by weight in terms of SiO ₂ based on the Mg—Al hydrotalcite type particle powder. If the content is less than 0.05% by weight, it is difficult to coat the surface of the particles with a sufficient amount of silicon hydroxide or the like. 50.00% by weight
If it exceeds 3, the coating effect is saturated, and there is no point in adding more than necessary.

The coating of the particle surface with the higher fatty acid can be carried out by either a dry surface treatment or a wet surface treatment.
When performing dry surface treatment, a Mg-Al-based hydrotalcite-type particle powder is mixed with a Henschel mixer, a sand mill,
Put in an edge runner, a taninaka type crusher, a grinder, etc., add a higher fatty acid and dry mix.

As higher fatty acids, stearic acid, lauric acid, oleic acid and the like can be used. Preferred are stearic acid and lauric acid.

In the case of performing wet surface treatment, a higher fatty acid salt aqueous solution is added to an aqueous suspension obtained by dispersing Mg-Al-based hydrotalcite particles to adjust the water temperature to 20 to 90.
C. or by mixing and stirring, or, if necessary, by adjusting the pH value after mixing and stirring.
The particle surface of the g-Al-based hydrotalcite-type particles is coated with a higher fatty acid, and then filtered, washed with water, dried,
Smash.

As higher fatty acid salts, sodium stearate, sodium laurate benzenesulfonate, sodium oleate and the like can be used. Preferred are sodium stearate and sodium laurate benzenesulfonate.

The amount of the higher fatty acid salt or higher fatty acid added is
For Mg-Al-based hydrotalcite type particle powder, C
It is 0.2 to 20.0% by weight in conversion. If it is less than 0.2% by weight, it is difficult to coat the surface of the particles with a sufficient amount of higher fatty acid. If it exceeds 20.0% by weight, the coating effect is saturated, so that there is no point in adding more than necessary.

The coating of the particle surface with the organosilane compound is as follows:
The Mg-Al-based hydrotalcite-type particle powder is put into a Henschel mixer, a sand mill, an edge runner, a Taninaka-type pulverizer, a grinder, or the like, and an organic silane compound is added and dry-mixed.

As the organic silane compound, decyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane and the like can be used. Preferred are decyltrimethoxysilane and γ-aminopropyltriethoxysilane.

The amount of the organic silane compound added is Mg-Al
0.1% in terms of C with respect to the hydrotalcite-based particles.
2 to 18.0% by weight. If the amount is less than 0.2% by weight, it is difficult to coat a sufficient amount of the organosilane compound on the particle surface. If it exceeds 18.0% by weight, the coating effect is saturated, so that there is no point in adding more than necessary.

The surface of the particles can be coated with rosins by either a wet surface treatment or a dry surface treatment. When performing wet surface treatment, an aqueous solution of a water-soluble rosin is added to an aqueous suspension obtained by dispersing Mg-Al-based hydrotalcite particles, and the water temperature is adjusted to 20 to 90 ° C., followed by mixing and stirring. Or, if necessary, by adjusting the pH value after mixing and stirring, so that the particle surface of the Mg-Al-based hydrotalcite-type particles is coated with a rosin, and then filtered, washed with water, and dried. ,Smash.

In the case of performing the dry surface treatment, the Mg-Al-based hydrotalcite-type particles are mixed with a Henschel mixer.
Put in a sand mill, edge runner, taninaka type pulverizer, grinder, etc., add rosins and dry mix.

As rosins, water-soluble rosin can be used when performing a wet surface treatment, and natural rosin and hydrogenated rosin can be used when performing a dry surface treatment.

The amount of rosins added is 0.2 to 2 in terms of C with respect to the Mg-Al-based hydrotalcite-type particles.
5.0% by weight. If it is less than 0.2% by weight, it is difficult to coat a sufficient amount on the particle surface.
If it exceeds 25.0% by weight, the coating effect is saturated, so that there is no point in adding more than necessary.

[0073]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical embodiment of the present invention is as follows.

The plate surface diameter of the hydrotalcite-type particles is indicated by the average of the values measured from the electron micrograph.

The thickness of the particles of the hydrotalcite-type particles can be measured using an X-ray diffractometer RAD-2A (Rigaku Corporation).
(Tube: Fe, tube voltage: 40 kV, tube current: 20)
mA, goniometer: wide-angle goniometer, sampling width: 0.010 °, scanning speed: 0.5 ° / min,
(Divergence slit: 1 °, scattering slit: 1 °, light receiving slit: 0.30 mm), and the value calculated using the Scherrer equation from the diffraction peak curve of the (003) crystal plane of the hydrotalcite particles. It is a thing.

The identification of the hydrotalcite-type particle powder is X
It was performed by a line diffraction measurement. The X-ray diffraction measurement was performed using the X-ray diffractometer at a diffraction angle 2θ of 5 to 90 °.

Composition formula [Mg _x Ca _y ] · Al _z · (OH) ₂ · A ⁿ _-p · m in Mg-Al type hydrotalcite type particle powder
The indices x, y, and z in H ₂ O were determined by dissolving Mg-Al-based hydrotalcite-type particles with an acid, and measuring with a “plasma emission spectrometer SPS4000 (Seiko Instruments Inc.)”. .

Note that CO _{3 is used} as the anion (A ⁿ⁻ ).
^2- The carbonate ion content when used, and the coating amount of higher fatty acids, organic silane compounds, and rosins on the particle surface were measured using a carbon sulfur analyzer: EMIA-2.
The carbon content (% by weight) was measured and evaluated using a 200 (manufactured by HORIBA). The coating amount of higher fatty acids, organic silane compounds, and rosins on the particle surface was evaluated based on the increase in carbon content before and after the surface treatment.

The amount of Si present on the particle surface of the Mg—Al-based hydrotalcite-type particles was measured by using a fluorescent X-ray analyzer 3063M (manufactured by Rigaku Corporation) according to JIS.
The measurement was performed in accordance with K0119 “General rules for X-ray fluorescence analysis”.

The specific surface area was indicated by a value measured by the BET method.

The powder pH value was determined by weighing 5 g of a sample into a 300 ml Erlenmeyer flask, adding 100 ml of boiled pure water, heating and maintaining the boiled state for about 5 minutes, then stoppering and allowing to cool to room temperature. Then, after adding water corresponding to the weight loss, stoppering again, shaking for 1 minute, and allowing to stand for 5 minutes, the pH value of the obtained supernatant was measured according to JIS Z 8802-7, and the obtained value was measured. The powder pH value was taken.

The heat resistance time of the Mg—Al hydrotalcite-type particles in the vinyl chloride resin was evaluated by the above method.

<Production of Mg-Al-based hydrotalcite-type particle powder> The CO ₃ ^2- ion concentration was 0.875 mol.
/ Ml of sodium carbonate aqueous solution 500ml and 5.308m
ol / l sodium hydroxide aqueous solution 3 l (pH = 1
4.2) is mixed, kept at 60 ° C. and stirred in the reaction vessel. A mixed solution of 500 ml of 3.75 mol / l magnesium sulfate aqueous solution and 500 ml of 0.625 mol / l aluminum sulfate aqueous solution was added thereto,
200 ml of 0.75 mol / l calcium chloride aqueous solution
Was added to bring the total volume to 5 l. The mixture was aged at a pH of 12.5 and 95 ° C. for 18 hours while stirring in the reaction vessel to produce a white precipitate. The white precipitate was filtered, washed with water,
By drying at 0 ° C., white particle powder was obtained. As a result of identifying the white particle powder, it was confirmed that the white particle powder was hydrotalcite-type particle powder.

The obtained Mg-Al-based hydrotalcite-type particles had an average plate surface diameter of 0.40 μm and a thickness of 0.1 μm.
0605 μm and a BET specific surface area of 11.6 m ² /
g.

3 parts by weight of the above-mentioned Mg-Al-based hydrotalcite-type particles were mixed in the above composition ratio to prepare a kneaded sheet. The heat resistance time at 180 ° C. of the obtained sheet piece was 6 hours.

[0086]

An important point in the present invention is that a specific amount of an aqueous solution of a calcium salt is added in a coprecipitation reaction to obtain a Mg-Al-based hydrotalcite-type particle having a large plate surface diameter and an appropriate thickness under normal pressure. Is obtained.

Mg having a large plate surface diameter and an appropriate thickness
Although the reason why the -Al-based hydrotalcite-type particle powder can be obtained is still unknown, the present inventor has found that calcium having a large ionic radius can be added to the Mg-Al layer (brucite layer) by adding a calcium salt aqueous solution. It is thought that by penetrating into the network, distortion of the crystal structure caused by aluminum having a small ionic radius is eliminated, and crystal growth is promoted.

When the Mg-Al-based hydrotalcite-type particles according to the present invention are used for kneading a resin such as a chlorine-containing resin, the reason for the improvement in heat resistance is as follows. Is incorporated, and the hydrotalcite-type particle powder has a higher chlorine ion trapping ability, so that the ability to trap unstable chloride ions in the chlorine-containing resin is increased. It is possible to easily capture unstable chlorine ions in the chlorine-containing resin generated with it, and to suppress the decomposition of the chlorine-containing resin that progresses in a chain by chlorine ions, so that the stability of the resin is improved. thinking.

The Mg-Al-based hydrotalcite-type particles whose surface is coated with at least one selected from a higher fatty acid, an organosilane compound and a rosin, such as a hydroxide of silicon, according to the present invention are obtained by adding a chlorine-containing resin As a reason for further improving heat resistance when used in resin kneading applications such as, the present inventor has improved the dispersibility of hydrotalcite-type particle powder in resin, and uniformly dispersed in chlorine-containing resin. To, and due to the improved ability of the particle powder itself to capture unstable chloride ions in the chlorine-containing resin,
We believe that the stability and heat resistance of the resin will also be improved. It is also believed that the coating reduces the surface basicity of the Mg-Al-based hydrotalcite-type particles, thereby suppressing the decomposition of the resin and improving the stability and heat resistance of the resin.

[0090]

Next, examples and comparative examples will be described.

Examples 1 to 8 and Comparative Examples 1 to 7 Types and concentrations of magnesium compounds, types and concentrations of aluminum compounds, concentrations of sodium carbonate, concentrations of alkaline aqueous solutions, amounts of added calcium salts, concentrations of calcium salts, Except that the calcium salt addition time and the aging temperature were variously changed, Mg-A
1-type hydrotalcite-type particle powder was obtained. In Comparative Example 7, Mg-Al-based hydrotalcite-type particles were obtained using an autoclave.

Example 9 A suspension (concentration: 56.7 g / l) containing the Mg—Al-based hydrotalcite-type particles obtained in Example 1 was heated to 70 ° C., and No. 3 water glass 8.9 g was gradually added, and after the addition was completed, the mixture was aged for 60 minutes. Next, the resultant was filtered, washed with water, dried and pulverized to obtain a Mg-Al-based hydrotalcite-type particle powder whose particle surface was coated with a hydroxide of silicon or the like.

Examples 10 and 11 In the same manner as in Example 9 except that the addition amount of the Mg-Al-based hydrotalcite-type particle powder and No. 3 water glass was changed, the surface of the particles was changed to silicon hydroxide or the like. Mg-coated with
An Al-based hydrotalcite-type particle powder was obtained.

Example 12 500 g of the same Mg-Al-based hydrotalcite-type particles as obtained in Example 1 and 15 g of stearic acid were put into a Henschel mixer, and pulverized and mixed for 5 minutes. A coated Mg-Al-based hydrotalcite-type particle powder was obtained.

Examples 13 and 14 In the same manner as in Example 12, except that the addition amount of the Mg-Al-based hydrotalcite-type particles and the stearic acid was changed, the Mg-Al-based hydrotalcite-type particles whose surface was coated with stearic acid were changed. Al
A hydrotalcite-based particle powder was obtained.

Examples 15 to 19 In the same manner as in Examples 9 and 12, except that the type and amount of the surface treating agent were changed, Mg-Al-based hydrotalcites whose particle surfaces were coated with various surface treating agents were used. A site-type particle powder was obtained.

The production conditions at this time are shown in Tables 1 and 2, and various properties of the obtained Mg-Al-based hydrotalcite-type particles are shown in Tables 3 and 4.

[0098]

[Table 1]

[0099]

[Table 2]

[0100]

[Table 3]

[0101]

[Table 4]

[0102]

The Mg-Al-based hydrotalcite-type particles according to the present invention have a large plate surface diameter, an appropriate thickness, and excellent heat resistance when kneaded into a chlorine-containing resin. It is suitable as a stabilizer for chlorine-containing resins.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/524 C08K 5/524 9/06 9/06 (72) Inventor Akinori Yamamoto Naka-ku, Hiroshima-shi, Hiroshima 4-1-2, Funariminami Toda Kogyo Co., Ltd. Creative Center

Claims (4)

[Claims] 1. A sheet having a plate surface diameter of 0.1 to 1.0 μm, a thickness of 0.02 to 0.08 μm, and calcium
g and Al in a molar ratio of 0.01 to
An Mg-Al-based hydrotalcite-type particle powder containing 0.20, wherein the heat resistance time of the particle powder measured by the following measurement method is 4 hours or more.
-Al-based hydrotalcite-type particle powder. The resulting mixture 5 was prepared by mixing hydrotalcite-type particles and additives in a vinyl chloride resin at the following composition ratios.
0 g was kneaded using a hot roll to obtain a kneaded sheet. The kneading conditions are a kneading temperature of 155 ° C., a roll gap of 0.75 mm, and a kneading time of 3 minutes. Hydrotalcite-type particle powder: 3 parts by weight, vinyl chloride resin (degree of polymerization: 1300) (trade name: TK-1300, manufactured by Shin-Etsu Chemical): 100 parts by weight, diethylhexyl phthalate (DOP, manufactured by Daihachi Chemical): 50 Parts by weight, calcium stearate (primary reagent): 2 parts by weight, zinc stearate (primary reagent): 0.4 parts by weight, 1,3 diphenyl-1,3 propanedione (primary reagent): 0.2 parts by weight, Diethyl phosphate (primary reagent): 0.5 parts by weight. The obtained kneaded sheet is subjected to pressure treatment with a hot press,
A sheet piece (thickness 1.5 mm) was obtained. Pressing conditions are a pressing temperature of 160 ° C., a pressing pressure of 100 kg / cm ² , a pressing time of 1 minute, a pressing gap of 1.5 mm, and a processing amount of 35 g. The obtained sheet piece (20 mm × 20 mm) is placed in air 1
Place in an 80 ° C. oven and perform heat resistance test. The time during which the entire sheet piece turns black is defined as the heat resistance time. 2. The M according to claim 1, wherein the surface of the particles is coated with at least one selected from the group consisting of hydroxides or oxides of silicon, higher fatty acids, organosilane compounds and rosins.
A g-Al-based hydrotalcite-type particle powder, wherein a heat resistance time of the particle powder measured by the measurement method according to claim 1 is 4 hours or more. Powder. 3. Mg-Al according to claim 1 or claim 2.
Chlorine-containing resin stabilizer consisting of hydrotalcite-based particles. 4. An alkaline aqueous solution containing an anion,
A magnesium salt aqueous solution and an aluminum salt aqueous solution are mixed, and a calcium salt aqueous solution having a molar ratio of 0.01 to 0.20 with respect to the total mole number of Mg and Al is added to the mixed solution, and the pH value is 10 to 14. And aging at a temperature in the range of 60 to 105 ° C.
A method for producing Al-based hydrotalcite-type particle powder.