The influence of paraffin wax on the burning properties and quality of candles By Marc Pruesmann Sasol Wax, C.A.

Content Complexity of candle production – Types and production methods Paraffin wax as a raw material for candles – Peculiarities of paraffin wax / Production process – Primary considerations in candle production – Different paraffin waxes for different applications Quality – Quality norms / International trends Burning – Smoking - Method for measuring soot

The complexity of candle production The natural history of a candle Michael Faraday

Types of candles Classification Candle / Light Outdoor Container light Grave light

Indoor

Free standing

Others

Votiv

Container light Tealight

Free standing Jar candle

Production principles (primary) – Moulding – Dipping – Extrusion – Pressing – Filling – Drawing

Cylindrical

Non Cylindrical

Floating

Candles produced in the region Production methods – Moulding – Extrusion – Jar filling – Labor intensive rather than dependent on machinery Candle types – Emergency and household candles – Sophisticated botanicals and pantallas – Ethnic style – Pillars – Sanctuary lights and pillars (velones)

Raw materials used for candles More than 90% of candles world-wide are made of paraffin wax.

2% 1% 1% 6%

Paraffin Wax Stearic Acid Beeswax Fats 90%

Others

Paraffin wax

Requirements of paraffin waxes in the candle industry Purity / safety

Burning process

Production process

Product stability

Peculiarities of paraffin wax as a raw material Complex mixture (n-alkanes, iso-alkanes, cycloalkanes). The dependence of wax properties on temperature. Crystallization (phase change from liquid to solid). Crystallization transition while in the solid form. Additional materials may influence crystallization (additives, color, fragrance). Burning of raw materials - burning behavior as the most important criteria for use.

Typical paraffin wax production

Medium I

ME

Medium III MD

Additives

Final products

Neutral oil II NZ

De-oiling

Neutral oil I NE

Base components

SE

Hydrogenation

Spindle oil

Base paraffin waxes

Slack wax families

Special components

Example of a carbon distribution of a paraffin wax 10 9

n-alkanes 75,5%

8

iso-alkanes 24,5%

7 6 5 4 3 2 1

C44

C43

C42

C41

C40

C39

C38

C37

C36

C35

C34

C33

C32

C31

C30

C29

C28

C27

C26

C25

C24

C23

C22

C21

C20

C19

C18

0

Parameters defining a paraffin wax Standard specification – Congealing point* (“Melting point”) – Oil content* – Penetration at 25°C – Color* (Saybolt) Additional specification – Viscosity at 100°C – Penetration at 40°C Classification* – FRP 58/60 etc. – SRP 56/58 etc.

Additional demands and requirements for paraffin wax – Color index – Odor – Ash content – Aromatic polycyclic hydrocarbon content – Sulfur content – UV stability According to German RAL Quality Mark

Primary considerations in candle production Crystallization properties – Radial and middle contraction (shrinkage) – demoulding properties – sinkholes / wells – detachment from the mould / adhesion to walls – bending / change of shape

– Crystallization effects – opacity – blotting / mottling

– Appearance of bubbles

Compatibility / solubility – Migration – haze – oil retention / bleeding – surface effects

– Reaction – – – –

transition changing / fading of colors change in fragrance deterioration

– Air solubility

Primary considerations in candle production (cont.) Rheological properties – Hardness / temperature dependence – bending – storage stability

– Plasticity – – – –

shaping (milling cutter) surface (extrusion) bonding stability (drawing)

Thermodynamic properties – Phase transition – solid / liquid – stickiness / adhesion (spraying, molding)

– Burning behavior – melting – dripping

Typical paraffin waxes used for candle production Application Typical paraffin wax / data

Properties required

Molding

CP: 58 – 64°C Oil: max. 0,5% Pen (25°C): max. 18 1/10 mm

Good radial contraction, detachment from walls homogeneous crystallization

Extrusion

CP: 58 – 64°C Oil: max. 0,8% Pen (25°C): max. 20 1/10 mm

Plasticity, resistance to bending, good bonding, smooth surface

Jar filling

Complex special blend CP: 40 – 50°C Pen (25°C): > 50 1/10 mm

Low shrinkage, good wall adhesion, defined melting and burning

Powder pressing (Pillar candles)

CP: 56 – 62°C Oil: max 1% Pen (25°C): max 20 1/10 mm

Adhesion to powder drum, no lumping of powder, transport, bonding

Powder pressing (Tealights)

CP: 50 – 54°C Oil: max. 1,5% Pen (25°C): 20 – 35 1/10 mm

Adhesion to powder drum, no lumping of powder, transport, bonding

Typical paraffin waxes used for candle production (cont.) Application Typical paraffin wax / data

Properties required

Overdipping

Complex special blend, CP: 58 – 62°C Pen (25°C): 12 – 18 1/10 mm Visc. (100°C): 5 – 15 mm²/s Microcrystalline blend CP: 62 – 72°C Pen (25°C): 10 - 20 1/10 mm Visc (100°C): 5 – 10 mm²/s Microcrystalline blend CP: 60 – 64°C Visc. (100°C): 6 – 10 mm²/s

Homogeneous film and color distribution, opacity, smooth surface, adhesion to core, stability Flexibility, stability, low tackiness, smooth surface

Drawing

CP: 54 – 58°C Oil: max. 0,5% Pen (25°C): 20 - 25 1/10 mm

Flexibility, adhesion of layers, stability

Dipping

CP: 58 – 62°C Oil: max. 0,5% Pen (25°C): 18 - 22 1/10 mm

Homogeneous crystallization, adhesion of layers, stability

Wick Wax

Ornamented candles (Silicone molds)

Plasticity, fine homogeneous crystal structure, detachment from molds

Quality

Environmental impact on the candle industry Proposition 65 (USA) – Discussion about soot “Ökotest” journal (Germany) – Discussion about sulfur Lead in the wick Hazardous combustion products Lilac candle (dioxin) Candle industry Environment

Overview of current norm projects RAL Quality Mark – Germany European Norm – Based on RAL Quality Mark ASTM – USA Retailer’s standard – e.g. Ikea, Pier 1 Imports

Candle quality parameters Visible – Candle as a product – – – – –

Shape Color Size / dimensions Weight Appearance

– Burning behavior – – – – –

Dripping Uniformity Flame size and apperance Burning bowl Smoking

Non-visible – Candle as a product – Sulfur – Halogens – Heavy metals

– Burning behavior – – – –

Aldehydes Dioxin Lead etc.

Factors which influence burning behavior Consideration of burning conditions (If necessary care of flame)

Use of high quality raw materials

Optimal wax - wick constellation

Quality parameters for burning candles Flame size and appearance – Wick, hourly consumption Guttering, dripping – Resistance to dripping Development of harmful substances – Purity criteria raw materials / tests DEKRA, Ökometric Smoking – Visible yes / no

Burning

Method for measuring smoking Development objectives – A simple, uncomplicated method – Can be integrated into the existing (RAL) test specifications – Not cost intensive – A quick, easy to evaluate method which is reproducible

Range of application – Visibly smoking candle – Candle burning without visible soot emission – Candle near “smoke point” – Ideal candle

Meets quality demands Fuel flow (g/h)

Equipment for a unit measuring smoking in burning candles Wire mesh cylinder

Detector unit (closed /open) Examples soot indexing

Glass plate

Complete system for testing the burning behavior of candles Digital video – Size and shape of the flame Computer controlled scales – Hourly fuel flow – Drip loss Wire mesh cylinder and detector unit – Soot index Digital thermometer – Temperature

Burn-off curve 10 9 8

Fuel flow (g/h)

7

71 min.

77 min.

6 5 4 3 2 1 0 0

10

20

30

40

50

60

70

Duration of burning (min)

80

90

100

110

120

Current status of norm projects EU Norm project – The standard will be divided into different parts to speed up the process – the priority will be smoking behavior – then the burning behavior of (indoor) candles – all other parts e.g. outdoor candles, candleholders, labeling etc. to follow

ASTM task groups – Consumer safety – – – – – – –

candle smoking test candle fire safety candle glass container terminology labeling lead wick fire data evaluation

Summary Use of special products and complex considerations necessary. Purity, harmlessness and safety aspects gain in importance. Quality control with emphasis on burning behavior. Standard method and maximum limits necessary. Consumer assurance through customer information (quality seal). Maintain a positive image for the candle.

The complete solution Training

Patents and Publications

Machines

Fragrances

Colours

Specialized Products Paraffin Waxes

Polymers Beeswaxes

Soft Paraffin Waxes

Paraffin Waxes

Additives 35 - 40 °C

45 - 60 °C

Stearic Hard

Acid

Waxes

Fats

70 - 100 °C

Blends Burning Properties Member of Associations

Wicks

Lacquers Quality Awareness