PVCsuspendingpolymerization

PVC additives made by Kuraray

Specialities forpolymerization
processes
Kuraray has a long history in the development of polyvinyl alcohol (PVA orPVOH) based suspending agents especially for the needs of PVC manufacturers. In these applications polyvinyl alcohol is used as a protective colloid forthe polymerisation of PVC: vinyl chloride monomer is suspended in water bymeans of stirring in combination with a suspending agent to allow the polymerisation reaction to proceed. The physical properties of the resulting PVC,
including size, shape of the grains and bulk density, are directly related to thegrain forming process during polymerisation. Kuraray’s primary and secondary
suspending agents allow precise control of the grain formation and its resulting structure and morphology. Furthermore, the surface active performancecan be widely optimised by selecting an appropriate combination of Kuraray’ssuspending agents. This diversity enables the PVC manufacturer to produce avery versatile range of PVC resins, varying in morphology and K value according to the intended end application.

Kuraray suspending agents

Easy handling –precise control
Kuraray’s polyvinyl alcohol based primary suspending agents(L-series) enable accurate control of the grain size distribution of the PVC resin. A high degree of uniformity from grain
to grain as well as a narrow grain size distribution is required
to avoid the formation of a coarse fraction that could give rise
to fisheyes or other defects, and also make VCM (Vinyl Chloride Monomer) removal difficult.
PVC grains must be able to absorb a variety of compounding
additives including plasticizers, lubricants and stabilisers toname just a few. For this purpose PVC resin must have somedegree of porosity that can be measured using cold plasticizer absorption (CPA).
Porosity in PVC grains is created by a complex series of interrelated steps in the formation and growth of a sub-microscopic structure within each droplet. It also depends on theunique nature of the VCM / PVC system. Kuraray’s secondary
suspending agents (LM-series) improve the porosity of systems.
In addition to the porosity, the control of bulk density (BD)or apparent density (AD), which mainly depends on porosity,
grain shape and grain size, is critical to the PVC processor,
who is concerned with charge size, cycle times in high speed
mixers, output rates, motor torque and degree of gel formation in extruders.
Kuraray’s secondary suspending agents (LM-series) are solidgrades, which are self-dispersible in cold water. LM-series canbe charged directly into the reactor as a dispersion.

Specialty polyvinyl alcohol

Supporting the versatilityof PVC products
Thanks to the diversity of Kuraray’s primary and secondary
suspending agents the PVC manufacturerer can produce a
versatile range of PVC polymers which vary in morphology
and K-value, according to the intended end application. Our
expertise in the development of primary and secondary suspending agents enables us to support our customers in processing rigid or flexible formulations as well as low K-value
formulations.
Rigid formulations are used to produce PVC articles of low
flexibility and good impact resistance for example rigid pipe,
guttering and decorative siding in house construction. Flexible formulations are used to produce PVC articles of highflexibility for cable covering, hoses and medical tubing applications. Low K-value formulations are ideal for injection
moulding processes, conduit fittings, and electrical plugs.
Furthermore they can be applied in blow moulding of bottles
and other containers.

Adding value toyour products –worldwide
Kuraray Poval™, Exceval™, Elvanol™ and Mowiflex™ are the trademarks for polyvinyl alcohols
made by Kuraray. Their key characteristics — outstanding film-forming properties and high binding strength — add real value to your products. Our polymers are water-soluble, highly reactive,crosslinkable and foamable. They have high pigment binding capacity, protective colloid characteristics and thickening effects. The physical and chemical properties of Kuraray Poval™ makeit ideal for a wide variety of applications, ranging from adhesives through paper and ceramics
to packaging films. Many of our polymers are food contact-approved and thus suitable for foodapplications. Ecologically Kuraray Poval™ is advantageous due to its biodegradability and the factthat combustion does not generate residues. It is available in various particle sizes from granules
to fine powders.
Kuraray produces its wide range of Kuraray Poval™ grades in Japan, Singapore, Germany and theUSA. Kuraray’s global production and service network make us your partner of choice for innovative high-quality PVOH resins.
Kuraray – Here to Innovate.

Headquarters
Kuraray Co., Ltd.
Tokiwabashi Tower
2-6-4, Otemachi
Chiyoda-ku
Tokyo, Japan 100-0004
Phone: +81 3 67 01 1000
infopoval.jp@kuraray.com

Kuraray Poval™
product portfolio
Please contact your local
Kuraray office to discuss theright Kuraray product foryour needs.

Kuraray America, Inc.
2625 Bay Area Blvd.,
Suite 600 Houston, TX77058
United States of America
Phone: +1 800 423 9762

Kuraray Asia Pacific Pte., Ltd.
250 North Bridge Road
#10-01/02 Raffles City Tower
Singapore 179101
Phone: +65 6337 4123

info.kuraray-poval@kuraray.com

infopoval.sg@kuraray.com

Kuraray Europe GmbH
Philipp-Reis-Str. 465795 Hattersheim am Main,
Germany
Phone: +49 69 305 85 351

Kuraray China Co., Ltd.
Unit 2207, 2 Grand Gateway
3 Hongqiao Road, Xuhui District,
Shanghai 200030, China
Phone: +86 21 6119 8111

info.eu-poval@kuraray.com

infopoval.cn@kuraray.com

09_2021