Modes of action
An examination of emulsifiers offered for cold processing shows they fall into distinct groups. Those for w/o emulsions tend to be polyglyceryl esters; for o/w emulsions there is a predominance of alkoxylated alcohols and phosphorous compounds; there is a group of silicone-based emulsifiers; and a number based on polymer chemistry. Most emulsifying systems work by reducing surface tension but it is also possible to make stable emulsions using polymers that hold the internal phase droplets in suspension. An example of these is the Rheosol range from Rheolab Laboratories, which are based on acrylate or polyacrylate polymers and are supplied pre-dispersed in oils or esters to which the aqueous phase can be added with rapid stirring. Anionic and cationic versions are available, they do not require a neutralisation step and other oil phase ingredients may also be added.
Simulgel INS 100 [INCI: Hydroxyethyl acrylate/sodium acryloydimethyl taurate copolymer, isohexadecane, polysorbate 60] from Seppic is described as a thickening and emulsifying agent in liquid form that requires no pre-dispersion or neutralisation. It emulsifies all types of oil phases without heating to form cream gels with a fresh texture that melts on contact with the skin leaving a feeling of velvety softness. Also from Seppic, Sepimax ZEN [INCI: Polyacrylate crosspolymer-6] forms electrolyte tolerant gels that can incorporate 20% oil phase and remain stable.
The Jeesperse CPW range from Jeen is based on sodium polyacrylate in combination with polyethylene or other cosmetic ingredients. The Jeesperse is added to the aqueous phase with stirring, then the oil phase added and a stable emulsion is formed. The results are said to have a luxurious skin feel for gel-type emulsions and the CPW-2 grade has been used to prepare sunscreen gels containing 10% mixed UV absorbers to give SPF15.
The emulsifying polymer Cosmedia SP [INCI: Sodium polyacrylate] from Cognis is said to enable formulators to achieve very stable emulsions that are easy to spread and feel light and silky on the skin. It is compatible with a range of different oil phases including vegetable and silicone oils and with polar solvents such as ethanol. Oil is trapped in gel pores, leading to high emulsion stability, and it may be used to prepare low viscosity sprays and lotions, but is also suitable for thicker, richer cream formulations.
Submica M [INCI: Mica] from Sensient Technologies can be used to formulate very stable surfactant-free w/o emulsions containing up to 30% of aqueous phase dispersed in non-polar oils. Also based on mica, Submica E from the same company is added to the water phase to form an opaque cream-like gel with a good feel on the skin. Its particles are small platelets that have different polarities on the two big faces (negatively charged) and the four small faces (positively charged). In water these particles get organised due to electrostatic forces and build a house of cards structure that increases the viscosity of the aqueous phase. Droplets of oil can be trapped within the Submica E house of cards structure and it is possible to emulsify up to 20% oils.
Formulation guidance
Croda recently published a comprehensive guide to cold processing entitled Blue: a practical pathway to Green. It starts with a method for comparing the energy requirements of conventional hot processing to those needed for cold mixing, showing that savings could be as high as 80%. It describes hybrid emulsifiers that consist of more than one ingredient, such as the Versaflex and PolaSperse mixtures; it describes anionic surfactants from the Crodafos and Crodasinic ranges; amphoterics like Crodateric CAB 30 and Crodateric CAS 50; and a number of sugar esters. Also described are the well known Span and Tween non-ionic emulsifiers and numerous ethoxylated triglycerides, fatty alcohols and sorbitol as well as various cationic materials suitable for processing hair conditioning products. The principal functions and properties of each of these materials are listed together with suggested applications. Other ingredients suitable for cold processing are shown and the brochure contains numerous formulations that illustrate the types of products suitable for manufacture using cold processing technology.
วิธีการดำเนินการการตรวจสอบสำหรับประมวลผลเย็น emulsifiers แสดงจะตกอยู่ในกลุ่มที่แตกต่างกัน ผู้การเดิม emulsions มัก polyglyceryl esters สำหรับ o/w emulsions มีความเด่นของ alkoxylated alcohols และสาร phosphorous มีกลุ่มของซิลิโคนตาม emulsifiers และตัวเลขตามเคมีพอลิเมอร์ สุดสกัดระบบทำงาน โดยการลดแรงตึงผิว แต่ก็ยังสามารถทำการใช้โพลิเมอร์ที่หยดระยะภายในระงับ emulsions มั่นคง ตัวอย่างเหล่านี้มีตั้งแต่ Rheosol Rheolab ห้องปฏิบัติการ ซึ่งขึ้นอยู่กับโพลิเมอร์ acrylate หรือ polyacrylate และให้กระจายล่วงหน้าในน้ำมันหรือ esters ที่ระยะอควีสามารถเพิ่มกับกวนอย่างรวดเร็ว รุ่นย้อม และ cationic มี พวกเขาไม่ต้อง neutralisation ขั้นตอน และยังสามารถเพิ่มส่วนผสมอื่น ๆ น้ำมันระยะSimulgel อิน 100 [INCI: Hydroxyethyl acrylate/โซเดียม acryloydimethyl taurate โคพอลิเมอร์ isohexadecane, polysorbate 60] จาก Seppic ได้อธิบายไว้เป็นตัวหนาและตัวแทนในแบบฟอร์มสภาพคล่องที่ไม่กระจายตัวก่อนหรือ neutralisation สกัด มัน emulsifies น้ำมันระยะโดยฟอร์มครีมเจมีเนื้อสดที่ละลายบนติดต่อกับผิวที่ออกจากความรู้สึกของความนุ่มนวล velvety ความร้อนทุกชนิด นอกจากนี้จาก Seppic, Sepimax เซน [INCI: Polyacrylate crosspolymer-6] น้ำมันระยะฟอร์มอิเล็กโทรทนกับเจที่สามารถรวม 20% และยังคงมีเสถียรภาพThe Jeesperse CPW range from Jeen is based on sodium polyacrylate in combination with polyethylene or other cosmetic ingredients. The Jeesperse is added to the aqueous phase with stirring, then the oil phase added and a stable emulsion is formed. The results are said to have a luxurious skin feel for gel-type emulsions and the CPW-2 grade has been used to prepare sunscreen gels containing 10% mixed UV absorbers to give SPF15.The emulsifying polymer Cosmedia SP [INCI: Sodium polyacrylate] from Cognis is said to enable formulators to achieve very stable emulsions that are easy to spread and feel light and silky on the skin. It is compatible with a range of different oil phases including vegetable and silicone oils and with polar solvents such as ethanol. Oil is trapped in gel pores, leading to high emulsion stability, and it may be used to prepare low viscosity sprays and lotions, but is also suitable for thicker, richer cream formulations.Submica M [INCI: Mica] from Sensient Technologies can be used to formulate very stable surfactant-free w/o emulsions containing up to 30% of aqueous phase dispersed in non-polar oils. Also based on mica, Submica E from the same company is added to the water phase to form an opaque cream-like gel with a good feel on the skin. Its particles are small platelets that have different polarities on the two big faces (negatively charged) and the four small faces (positively charged). In water these particles get organised due to electrostatic forces and build a house of cards structure that increases the viscosity of the aqueous phase. Droplets of oil can be trapped within the Submica E house of cards structure and it is possible to emulsify up to 20% oils.Formulation guidanceCroda recently published a comprehensive guide to cold processing entitled Blue: a practical pathway to Green. It starts with a method for comparing the energy requirements of conventional hot processing to those needed for cold mixing, showing that savings could be as high as 80%. It describes hybrid emulsifiers that consist of more than one ingredient, such as the Versaflex and PolaSperse mixtures; it describes anionic surfactants from the Crodafos and Crodasinic ranges; amphoterics like Crodateric CAB 30 and Crodateric CAS 50; and a number of sugar esters. Also described are the well known Span and Tween non-ionic emulsifiers and numerous ethoxylated triglycerides, fatty alcohols and sorbitol as well as various cationic materials suitable for processing hair conditioning products. The principal functions and properties of each of these materials are listed together with suggested applications. Other ingredients suitable for cold processing are shown and the brochure contains numerous formulations that illustrate the types of products suitable for manufacture using cold processing technology.
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