General Introduction

Hydrotalcite(Layered double hydroxidesof Mg/Al and carbonate type)Hydrotalcite
Hydrotalcite is a kind of naturally yielded clay mineral. The typical chemical composition is acarbonic acid type, and the composition is Mg6Al2(OH)16CO3･4(H2O). TODA KOGYO artificiallysynthesizes hydrotalcite.
Hydrotalcite is generally represented layered double hydroxides (LDH) of Mg/Al and carbonate type.
Anions such as chloride ion (Cl-) are adsorbed by ion exchange with carbonate ion (CO32-) between
Mg/Al type layers. In addition, the contained carbonate ion (CO32-) absorbs infrared rays and exert aheat storage and heat retention effect. Hydrotalcite also have other functions such as water adsorption
or an acid adsorbent for rubber containing halogen.

TODA KOGYO’s hydrotalcite has been used for the following applications by taking the features.
 Environmentally friendly lead-free materials for polyvinyl chloride stabilizers.
 Heat retaining agent for agricultural polyolefin film.
 Ion trap materials for semiconductor encapsulants.
 Anion adsorbent for water treatment.

Our long-cultivated wet synthesis technologies enable us to design theoptimum particle shape and control the composition for various applications.

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Crystal structure of hydrotalcite
Typical composition：Mg6Al2(OH)16CO3 ･4H2O

Positive charge layer

Negative charge layer

Positive charge layer

Characteristic

Application

・Exchangeable with various anions
・Variable Mg/Al ratio (1.5≦Mg/Al≦4.0)
・Dehydration by heating, porousization
by decarboxylation
3Adsorbent
Catalyst carrier, etc.

3

Hydrotalcite manufactured by TODA KOGYO

Averageparticle size
BET specificsurface area

Large particles

Middle particles

Small particlesnm30020060212～14

13～15

40～45

m /gTransmission
electron microscopeElectronmicrograph
image

500nm

500nm

500nm

“Particle size control technology” + “Features of hydrotalcite”⇒ Expansion to various applications
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Functions and applications of hydrotalcite
Ⅰ. Intercalation of various anions
・ PVC stabilizer (non-toxic : lead substitute)・ Various anion absorbents

Ⅱ. Colorless additives by combination of colorless metals
・ Heat retaining agent for agricultural PO film
(Far infrared absorption capability + Transparency)
・ Transparent resin additives (Acid acceptor, filler, etc.)

Ⅲ. Combination of various metals (divalent or trivalent)
・ Immobilization of functional metals (Ni, Cu, Fe · · ·)for catalyst applications

Ⅳ. Reversible changes in hydroxide and oxideby heating/hydration
・ Humidity controlled by moisture control, absolutely dry function5

Ⅰ. Intercalation of various anions
PVC stabilizer
It’s used as the additive which improves durability for ultraviolet rays or heat.

Hydrotalcite captures chlorine desorbed due to deterioration.

CH2OH－CO32-CH

Mg2+ or Al3+H2O

ClDesorption

Cl-CO32Intercalation

Accelerated degradation test of vinyl chloride resin. *Comparison of appearance change depending on heat time at 190℃
Heat time (min.)0204060

Without hydrotalcite

80100120140160180―――With hydrotalcite⇒ It can be seen that the deterioration is significantly suppressed by addition of hydrotalcite.

6Ⅰ. Intercalation of various anions
Chlorine capture for semiconductor encapsulants
A semiconductor encapsulant is one of the materials that make up asemiconductor package to protect a semiconductor from light, heat,humidity, dust, and shock. It consists of resin materials such as epoxy andsilicone, curing agents, fillers, and additives.
One of the additives is an anion adsorbent, and hydrotalcite is used as itsmaterial. Hydrotalcite captures chlorine ions contained in the resin material
and prevents disconnection of the wiring circuit.

 High chlorine capture ability.
Chlorine adsorption performance evaluation（Pressure Cooker Test）

 Fine particle design for fine wiring.

100

Hydrotalcite(Chlorine ion capture)

Encapsulant

Cl-ClCl-

Residual chlorine%）
Residualrate of （chloride(%)

Semiconductor chip image

Cl-Cl-Cl-

90
80706050403020100BlankBlank
Wiring damage caused bychlorine ions

IC chip

CurrentproductDevelopmentsample* Bisphenol epoxy resin + amine-based curing agent 100%，Hydrotalcite 2.0 %* Pressure cooker test : sample/ion-exchanged water = 5.0g/50ml, 120℃＊24hr

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Ⅱ. Colorless additives by combination of colorless metals
Heat retaining agent for agricultural PO film
Hydrotalcite is used in agricultural polyolefin film as an additive that can impart high far infrared absorption
capability without impairing transparency.

 Refractive index control.
 High infrared absorption capability.
About 1400cm-1 absorption band of hydrotalcite absorb heat ray radiation from the ground and plants.

Heatray(b) PO film with hydrotalcite
VisiblelightVisible
light0.5

Absorption of heat
ray radiation

0.4

Absorbance
吸光度(Abs)(a) PO film without hydrotalcite

Heatray

ハイドロタルサイト
Hydrotalcite

0.3
0.2
0.1
0

Transparent but no heat retention⇒ The temperature drops at night.

Transparent and heat retaining⇒ The temperature does not drop
even at night.

850080011001400-1) -1)
Wave 波数(cmnumber (cm1700

Absorbance of hydrotalcite

2000

Ⅲ. Combination of various metals
Catalyst for steam reforming
Hydrotalcite can immobilize various metals. Therefore, it is used as a carrier in catalyst applications. In steam
reforming catalyst applications, it is possible to provide highly active and durable catalysts without using preciousmetals. The nano-Ni catalyst produced by our unique synthesis technologies make this possible.

 High dispersion with single nano size nickel.
 High catalytic activity.

General Ni catalyst

TODA KOGYO’s Ni catalyst(BET：37.6 m2/g)(BET：2.8 m2/g)

Ni metal
Ni metal

Ni metal

Ni metal

Carrier

Carrier

50nm

Particle surface image

50nm

9Particle surface image

【Contact】
TOKYO OFFICE
Shiba Mita Mori Building 6F, 5-13-15 Shiba
Minato-ku,Tokyo 108-0014, Japan
TEL. +81-3-5439-6040 FAX. +81-3-5439-6045

https://www.todakogyo.co.jp/english/

webmaster@todakogyo.co.jp

The information presented in this document may be changed without notice.

Ver. Mar. 2022