A toilet rim block is a substance in the shape of a block that is used in
flush toilet
A flush toilet (also known as a flushing toilet, water closet (WC) – see also toilet names) is a toilet that disposes of human waste (principally urine and feces) by using the force of water to ''flush'' it through a drainpipe to another loca ...
s, which slowly dissolves in water. The blocks usually come in a small holder that is attached over the rim of a toilet and hangs down into the bowl, so as the toilet gets flushed, the water passes through the holder coming into contact with the block. With "liquid rims", however, liquid is held in a small bottle above—and connected to—the holder that slowly releases into the bottom of the holder (which is beneath the toilet rim), and so coming into contact with the water when the toilet is flushed.
However, the blocks also come ''loose'', for placement directly ''in-cistern'' (and therefore usable with
squat toilet
A squat toilet (or squatting toilet) is a toilet used by squatting, rather than sitting. This means that the defecation posture used is to place one foot on each side of the toilet drain or hole and to squat over it. There are several types of ...
s that lack the same sort of rim), although these tend to be slightly different in composition, so as to dissolve slower, due to the constant contact with water. These may also contain a
colorant A colourant/colour additive (British spelling) or colorant/color additive (American spelling) is a substance that is added or applied in order to change the colour of a material or surface. Colourants can be used for many purposes including printi ...
(typically blue or green) which shows up in the pan or bowl water.
Composition and action
Toilet rim blocks are marketed as
disinfectant
A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than s ...
s and
deodorizers, while allegedly also helping to prevent the buildup of
limescale
Limescale is a hard, chalky deposit, consisting mainly of calcium carbonate (CaCO3). It often builds up inside kettles, boilers, and pipework, especially that for hot water. It is also often found as a similar deposit on the inner surfaces of ol ...
in the toilet bowl.
The composition of toilet blocks can vary, but they may contain (among other components):
borax
Borax is a salt (chemistry), salt (ionic compound), a hydration (chemistry), hydrated borate of sodium, with chemical formula often written . It is a colorless crystalline solid, that dissolves in water to make a base (chemistry), basic aqueo ...
(an ingredient of many detergents),
hydroxyethylcellulose (a
gelling agent
A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state, although the liquid phase may still dif ...
),
troclosene sodium (a disinfectant),
sodium dodecylbenzenesulfonate (a
surfactant
Surfactants are chemical compounds that decrease the surface tension between two liquids, between a gas and a liquid, or interfacial tension between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, fo ...
),
sodium percarbonate
Sodium percarbonate is a chemical substance with formula . It is an adduct of sodium carbonate ("soda ash" or "washing soda") and hydrogen peroxide (that is, a perhydrate) whose formula is more properly written as 2 · 3 . I ...
(a form of oxygen
bleach),
sodium carbonate ("washing soda"), and various perfumes like, e.g.,
limonene
Limonene is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the oil of citrus fruit peels. The -isomer, occurring more commonly in nature as the fragrance of oranges, is a flavoring ...
,
butylphenyl methylpropional, and
linalool
Linalool () refers to two enantiomers of a naturally occurring terpene alcohol found in many flowers and spice plants. Linalool has multiple commercial applications, the majority of which are based on its pleasant scent (floral, with a touch o ...
.
/ref>
As in the closely related urinal deodorizer block
Urinal deodorizer blocks (commonly known as urinal cakes, urinal cookies, urinal biscuits (piscuits), urinal donuts, toilet lollies, trough lollies, urinal mints, urinal pucks, hockey pucks, toilet pucks, or urinal peons (pee-ons) are small disinf ...
s, some of the ingredients have irritating effects when applied to skin, eyes, or when swallowed. Their ecotoxicity is rated to be harmful to aquatic organisms and these chemicals may have long-term adverse effects for an aquatic environment.
See also
* Household chemicals
Household chemicals are non-food chemicals that are commonly found and used in and around the average household. They are a type of consumer goods, designed particularly to assist cleaning, house and yard maintenance, cooking, pest control and ge ...
* Ecological footprint
The ecological footprint is a method promoted by the Global Footprint Network to measure human demand on natural capital, i.e. the quantity of nature it takes to support people or an economy. It tracks this demand through an ecological accounti ...
* List of health articles
References
{{reflist
Hygiene
Cleaning products
Toilets