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SC formulations 水悬浮剂. Suspension Concentrates 海利尔 农药 论坛 (第十届山东省农药信息交流会) 英国禾大公司 www.Croda.com. SC 水悬浮剂. 描述:固体颗粒悬浮于水中 Description: Solid particles suspended in water 常见问题 Issues 悬浮物质与水之间存在密度差 Density difference between suspended matter and water 如果原药密度大于 1 克 / 毫升将形成沉淀 - PowerPoint PPT Presentation
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SC formulations 水悬浮剂
Suspension Concentrates
海利尔农药论坛(第十届山东省农药信息交流会)
英国禾大公司 www.Croda.com
SC 水悬浮剂描述:固体颗粒悬浮于水中
Description: Solid particles suspended in water 常见问题 Issues
• 悬浮物质与水之间存在密度差 Density difference between suspended matter and water
• 如果原药密度大于 1 克 / 毫升将形成沉淀 Will form sediment if density is >1
• 如果原药密度大于 1 克 / 毫升将漂浮 Will float if density is <1
• 根据斯托克斯定律:较小的粒径是必须的 Stokes law: small particles are required
• 怎样获得较小的粒径 How to obtain small particles?
• 怎样保持粒子的悬浮稳定性 How to keep the particles suspended?• 结晶增长 Crystal growth
Formulation breakdown processes 制剂被破坏的过程
Reversible 可逆的
Irreversible 不可逆的
膏化沉淀
絮凝
相转化 聚结 奥氏熟化
Ca.i. small
小粒径
Oswald ripening 奥氏熟化• A.I. has limited water solubility
• 原药在水中有一定的溶解度• Solubility of small particle is higher than solubility of large particle
• 较小粒经的溶解度大于较大粒经的溶解度
Ca.i. large
大粒径
Ca.i. small 小粒经 >> Ca.i. large 大粒径
How to prevent Oswald ripening 怎样预防奥氏熟化的发生
较窄的粒径分布范围 Narrow particle size distribution
还有其他的诀窍 There are other tricks: Very limited amount of diluted oil in aqueous phase
将一定量的油稀释到水相中
To make an SC 水悬浮剂制备• Preparation of small particles 小粒子的
制备• Preventing flocculation• Preventing sedimentation
To make an SC 水悬浮剂制备• Preparation of small particles 小粒子的制备
• Small suspended particles are prepared by milling process 通过砂磨设备获得较小粒径
• Processing conditions are important 生产工艺条件很重要
To make an SC 水悬浮剂制备• Preparation of small particles 小粒子的
制备
Milling 砂磨
Wetting -> Dispersion -> stabilization润湿 —分散 —稳定性
Issue during milling process砂磨过程中出现的问题
• During milling process fresh surface is generated> 砂磨过程中新的粒子表面产生• Fresh surface is generally of non-polar nature en will
cluster together rapidly> 新产生的非极性的表面通常是的自然对开很容易迅速聚集• This could lead to increased viscosity and even mill
blockage> 这可能导致粘度增加甚至阻碍砂磨进程• To overcome mill blockage a wetting agent is
needed> 为了克服这一问题所以润湿剂的加入是非常必要的
To make an SC 水悬浮剂制备• Preparation of small particles• Preventing flocculation 絮凝的预防• Preventing sedimentation
How to prevent flocculation? 怎样预防絮凝的产生• Use of dispersants 分散剂的使用
• Dispersant should be firmly locked on substrate
• Anchoring 锚固作用• Dispersant types: 分散剂种类
• Anionic 阴离子 Electrostatic stabilisation 静电稳定作用• CaDDBS / NaDDBS (十二烷基苯磺酸钙 /钠)• Fosfate esters (磷酸酯类)
• Non ionic 非离子 Steric stabilisation 空间位阻稳定作用• Alcohol etoxylates (乙氧基醇醚类)• Polymeric dispersants (高分子表面活性剂)
• Mix of the two Electrosteric stabilisation 混合静电 / 空间位阻
• Naphtalene condensate sulfonates ( 萘磺酸盐甲醛缩合物 )• Lignin sulfonates (木质素磺酸盐类)
Electrostatic Stabilization静电排斥作用
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h
G
hGmax
Electrostatic静电学
Electrosteric静电空间
G
h
G
h
2Mh
G h
2p
Monomer 单体 -Polymer 高分子
Steric Stabilization 空间位阻作用
• 空间位阻是由于非离子表里面活性剂和 / 或高分子表面活性剂提供的 Steric barriers are produced by adsorption of nonionic surfactants and/or polymeric surfactant
• 由于链的不利交叉排斥和熵值作用对重大交叠的影响Repulsion is due to unfavourable mixing of the chains and entropic effects on significant overlap
Functions of surfactants表面活性剂的功能
• Wet 润湿• Disperse 分散
Functions of surfactants表面活性剂的功能
• Wet 润湿作用• Dynamic molecules to wet surface during
milling stage 在砂磨期间动态分子润湿新鲜的表面• Smaller molecules 分子量较小• Negative regarding stability 对稳定性有负面影响
• Disperse 分散作用• Larger molecules to stabilise suspended
particles 大分子对粒子提供稳定的悬浮支撑作用• Act slow 作用进程缓慢
Size does matter 分子大小关系
Dispersed Phase 分散内相
CONVENTIONAL DISPERSANT 常规分散剂
POLYMERIC DISPERSANT 高分子分散剂
Dispersed Phase 分散内相
2Mh
G h
2p
Monomer 单体 -Polymer 高分子
Steric Stabilization 空间位阻作用
• 空间位阻是由于非离子表里面活性剂和 / 或高分子表面活性剂提供的 Steric barriers are produced by adsorption of nonionic surfactants and/or polymeric surfactant
• 由于链的不利混合排斥和熵值作用对重大交叠的影响Repulsion is due to unfavourable mixing of the chains and entropic effects on significant overlap
Rheology profile wetting agent vs. polymeric
dispersant 润湿剂与高分子分散剂流变性特征对比
Wetting agent 润湿剂
Polymeric dispersant高分子分散剂
• No shear effect polymeric dispersant flow curve: suspension is properly stabilized 高分子分散剂在剪切作用下的流变曲线无影响:悬浮液相对稳定 • Wetting agent flow curve increases hugely at low shear: insufficient stabilisation 润湿剂在低剪切作用下的流变曲线明显增大:不够稳定• If wetting agent is required, use at low possible concentration!如果润湿剂是必须添加的,尽可能在最低添加量下使用
To make an SC 水悬浮剂制备• Preparation of oil droplets in water• Preventing coalescence• Preventing sedimentation 沉淀的预防
Stokes law 斯托克斯定律
Vs = velocity of settling /creaming 粒子沉降速度, cm/s;
η = viscosity 水悬浮剂粘度, Pa.S;
g = gravity 重力加速度, cm/s;
r = radius of sphere 分散介质粒子直径, cm;
Δδ = density difference sphere & continuous phase 分散粒子的密度与水的密度差
Vs=--------------------9η
2gr2Δδ
Stokes law 斯托克斯定律
Vs=--------------------9η
2gr2Δδ
No sedimentation if density of suspended matter and water phase are equal如果悬浮介质和水相之间没有密度差,沉淀问题就不可能发生
固相 / 液相密度差 =0
Stokes law 斯托克斯定律
Vs=--------------------9η
2gr2Δδ
•The smaller the particle size, the lesser sedimentation•粒径越小沉淀越慢•Note this a square function•值得注意的是称将速度与粒径的平方正相关•10 times the particle size is 100 times faster sedimentation•10倍的粒径大小差异将导致 100倍的沉降速度差别
粒径大小
Stokes law 斯托克斯定律
Vs=--------------------9η
2gr2Δδ
•Increased viscosity will reduce sedimentation
•提高粘度有利于减少沉降•However viscosity cannot be increased infinitely
•然而粘度不可能被无限制的增加•Need of shear thinning rheology modifier
•需要使界面内剪切力变小的流体改性物•Xanthan or Kelzan Gum provides this effect
•黄原胶可以提供这种作用
体系粘度
Rheology profile Kelzan gum黄原胶的流变学特征
Brookfield viscosity (room temp)
0
5000
10000
15000
20000
25000
0,1 1 10 100
spindle rate (rpm)
visc
. (m
P.s
)
Kelzan 0,3%
Kelzan 0,5%
粘度
转速
SC 水悬浮剂• General formula: 一般配方组成 成份 用量
• Suspended phase 分散相 40%• Dispersant 分散剂 4%• Wetting agent 润湿剂 0.5%• Glycerine 防冻剂 5.2%• Anti foam 消泡剂 0.1%• Preservative 防腐剂 0.1%• Kelzan gum 增稠剂 0.1%• Water 水 50%
• Issue: long term stability and emulsion stability upon dilution
问题:经时稳定性和乳液的稀释稳定性
Croda SC recommendation英国禾大公司在水悬浮剂方面的核心产品Dispersants: 分散剂
Atlox 4913 羧酸盐枝接物Atlox Metasperse 100L 羧酸盐修饰物Atlox Metasperse 500L 羧酸盐修饰物
Co dispersant/wetting agent:助分散剂 / 润湿剂Atlas G-5000 高分子嵌段共聚物Atlas G-5002L 高分子前段共聚物Atlox 4894 高分子前段共聚物
Traditional wetting agent: 传统润湿剂Synperonic A7 聚氧乙烯醇醚
Further guidelines 使用说明• Dispersant level 10% of dispersed phase 分散剂的用量通常是分散内相的 10%
30 % dispersed phase 30% 的分散内向3% total surfactants 需要 3% 的总的分散剂
Ratio dispersant/co-dispersant: 2:1 分散剂和助分散剂的比例为 2 : 1
• 2% Atlox 4913 分散剂• 1% Atlox 4894 助分散剂
With traditional wetting agent: 配以传统的润湿剂• 2% Atlox 4913 分散剂• 1% Atlas G-5002L 助分散剂• Minimum amount Synperonic A7 最小量的润湿剂
With traditional wetting agent传统的润湿剂用量的确定• Optimum approach:最理想的途径——三元复配组合
12 3
4 5 67 8 9 10
11 12 13 14 1516 17 18 19 20 21
22 23 24 25 26 27 2829 30 31 32 33 34 35 36 37
38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56
57 58 59 60 61 62 63 64 65 66 67
Dispersant 分散剂
Co-dispersant 助分散剂Wetting agent 润湿剂
Performance criteria: 评估标准•Milling efficiency 砂磨的效率•Storage stability 储存稳定性
Crystal growth; part II 结晶增长
Particle Size Distribution
0.01 0.1 1 10 100 1000 3000
Particle Size (µm)
0
1 2
3
4 5
6
7
Vol
ume
(%)
20477-89-1a 2.5% SC 4913 fridge 7 days, 24 August 2007 10:49:0220477-89-1b 2nd repeat 2.5% SC with 4913 oven 7 days, 24 August 2007 10:05:50
Particle Size Distribution
0.01 0.1 1 10 100 1000 3000
Particle Size (µm)
0 1 2 3 4 5 6 7 8
Vol
ume
(%)
20477-89-2a 2.5% SC 4913+A3 fridge 7 days, 24 August 2007 14:20:2320477-89-2b repeat 2.5% SC 4913 + A3 oven 7 days, 24 August 2007 10:12:12
PolymericDispersant高分子分散剂
Polymeric plus monomeric Dispersant高分子 /单体分散剂
Crystal growth; part II 结晶增长• Effect of surfactant micelles 表面活性剂胶体束的作用
油滴 oil droplets
固体颗粒solid
particles
Crystal growth; part II 结晶增长• Avoid micelle forming surfactants
避免使用产生胶体束的表面活性剂• Monomeric surfactants form relatively easy
micelles
单体表面活性剂相对容易形成胶体束• Polymeric surfactants do not form micelles
高分子表面活性剂不会形成胶体束