モンモリロナイト

外観

灰白色の粉末

定義

本品は、複合ケイ酸アルミニウムマグネシウムからなる粘土鉱物である。

溶解性

水またはエタノールにほとんど溶けない。

解説

モンモリロン石とも呼ぶ粘土鉱物の一種で水により膨潤する性質(原体積の7～10倍)が特徴。ベントナイトの主要構成鉱物である。スメクタイトsmectiteとも呼ばれる。化学成分X0.66Y6Z8O20(OH)4･2H2O,X：1/2Ca,Na,Y：Al,Mg,Fe3＋，Z：Si,Alで示され多種類の種がこれに属する。単斜晶系に属する層状構造の微細葉片状結晶。電子顕微鏡下に薄板状の形態が明らかにされるが，通常は粘土状または塊状集合体をなす。

用途

鋳物砂型の結合剤、窯業原料

化粧品の成分用途

不透明化剤、非活性剤系分散剤、親水性増粘剤、乳化安定剤、吸着剤、研磨.スクラブ剤、増量剤

化学的特性

Bentonite is a light yellow, creamy, pale brown or gray to black powder or granules.

使用

bentonite (bentonite clay) is used to regulate the viscosity and suspension properties of a cosmetic formulation. It also acts as an overall formula stabilizer. Bentonite’s water-absorption capabilities allow it to form a gelatinous mass. Considered a noncomedogenic raw material, bentonite is a colloidal aluminum silicate clay.

定義

A type of clay that is used as an adsorbent in making paper. The gelatinous suspension it forms with water is used to bind together the sand for making iron castings. Chemically bentonite is an aluminosilicate of variable composition.

調製方法

Bentonite is a native, colloidal, hydrated aluminum silicate, found in regions of Canada and the USA. The mined ore is processed to remove grit and nonswelling materials so that it is suitable for pharmaceutical applications.

一般的な説明

Bentonite is comprised primarily of the smectite group (montmorillonite) of clay minerals. It is widely used in various industrial applications such as clarification of edible and mineral oils, paints, cosmetics, and pharmaceuticals. It is also used as an adsorbent for the elimination of pollutants from wastewater.
The swelling property of bentonite is used to produce viscous water suspensions for bonding, plasticizing, and suspending applications. The presence of a large surface area of bentonite is due to the colloidal dispersion of the particles is the main reason for its application as an insecticide carrier, an emulsifier, and an emulsion stabilizer.

応用例（製薬）

Bentonite is a naturally occurring hydrated aluminum silicate used primarily in the formulation of suspensions, gels, and sols, for topical pharmaceutical applications. It is also used to suspend powders in aqueous preparations and to prepare cream bases containing oil-in-water emulsifying agents.
Bentonite may also be used in oral pharmaceutical preparations, cosmetics, and food products. In oral preparations, bentonite, and other similar silicate clays, can be used to adsorb cationic drugs and so retard their release. Adsorbents are also used to mask the taste of certain drugs.
Bentonite has been investigated as a diagnostic agent for magnetic resonance imaging.
Therapeutically, bentonite has been investigated as an adsorbent for lithium poisoning.

农业用途

Bentonite, also known as montmorillonite, volcanic clay, soap clay and amargosite, is a soft, plastic, lightcolored, porous rock consisting largely of colloidal silica. Composed essentially of clay minerals, it swells extensively when wet. Bentonite belongs chiefly to the montmorillonite group and has two varieties: (a) sodium bentonite, with a high swelling capacity in water, and (b) calcium bentonite, with negligible swelling capacity.
Bentonite is used variously as a suspending aid, a gelatinous slurry to extinguish fire, a paint thickener, and as a sealant for earthen pots. Bentonite is also widely used in metallurgy, soap manufacture, and in petroleum refining because of its high decolorizing power and strong adsorbing capacity.

安全性プロファイル

Poison by intravenous route causing blood clotting. Questionable carcinogen with experimental tumorigenic data.

安全性

Bentonite is mainly used in topical pharmaceutical formulations but has also been used in oral pharmaceutical preparations, food products, and cosmetics.
Following oral administration, bentonite is not absorbed from the gastrointestinal tract. Bentonite is generally regarded as a nontoxic and nonirritant material.
LD₅₀ (rat, IV): 0.035 g/kg

職業ばく露

This material is used as Fuller’s earth; as a mineral, natural, or synthetic fiber; as an emulsifier for oils; as a base for plasters; in cosmetics, in polishes and abrasives; as a food additive and others. Bentonites are aluminate silicate and can contain crystalline silica. The content varies widely from less than 1% to about 24% .

貯蔵

Bentonite is hygroscopic, and sorption of atmospheric water should be avoided.
Aqueous bentonite suspensions may be sterilized by autoclaving. The solid material may be sterilized by maintaining it at 1708℃ for 1 hour after drying at 1008℃.
Bentonite should be stored in an airtight container in a cool, dry place.

輸送方法

Bentonite is not cited in the DOT Performance- Oriented Packaging Standards.

不和合性

Aqueous bentonite suspensions retain their viscosity above pH 6, but are precipitated by acids. Acid-washed bentonite does not have suspending properties. The addition of alkaline materials, such as magnesium oxide, increases gel formation.
Addition of significant amounts of alcohol to aqueous preparations will precipitate bentonite, primarily by dehydration of the lattice structure.
Bentonite particles are negatively charged and flocculation occurs when electrolytes or positively charged suspensions are added. Bentonite is thus said to be incompatible with strong electrolytes, although this effect is sometimes used beneficially to clarify turbid liquids.
The antimicrobial efficacy of cationic preservatives may be reduced in aqueous bentonite suspensions, but nonionic and anionic preservatives are unaffected.
Bentonite is incompatible with acriflavine hydrochloride.

廃棄物の処理

Land fill disposal.

規制状況(Regulatory Status)

Accepted in Europe as a food additive in certain applications. Included in the FDA Inactive Ingredients Database (oral capsules, tablets and suspensions, topical suspensions, controlled release transdermal films and vaginal suppositories). Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.