Shanghai Daoqin Plastics Co., Ltd.

defoamer 也叫消沫 agent, resistant agent, defoamer 实际就 is remove foam 意思, it is types tool has relatively low surface force and relatively high surface active property, can made or remove system in foam material 质. in industrial production process in generate very more has foam, heavy retardant production degree, this need add defoamer remove this has foam.

1, coating material in bubbles generate and principle

in coating material production process in, 会卷入空 gas formed bubbles, coating material in certain Raw Materials 例如: surface active property agent, dispersant and other make bubbles stability.

in coating material process in generate bubbles, this main/primary 取决于 coating material methods. 例如: coating can in coating material in 卷入空 gas, gas spray coating very easy 卷入空 gas, in versus for relatively low wet degree conditions lower or in high temperature conditions lower spray coating very easy generate bubbles.

稳泡 principle:

马兰格尼效应（ surface active property agent liquid 体回流 phenomenon, heavy force function ）

静 electrical 效应:  surface active property agent electrical function make bubbles liquid film increase thick, from stability bubbles.

2, defoamer function principle

defoamer is in foam thin formed stage/phase or rear function:

dispersion uniform defoamer 渗透进入 foam elastic property film and in film in distribution, through surface force reduce thin 层破裂.

dispersion uniform defoamer 渗透进入 foam thin and formed mono separation film, make its force reduce, easy thin 层破裂.

含 hydrophobic water pellets defoamer has mechanism. this hydrophobic water pellets to thin surface, but also in thin 层 顶端吸附 surface active property agent. thin due to surface active property agent 缺失而破裂.

3, defoamer selection and assessment methods

defoamer must can in foam surface speed but also can fast speed 渗透, make foam speed 破裂. defoamer currently commonly used types type has has machine silicon type and polypropylene (PP) acid ester type.

has machine silicon type defoamer usually is poly silicon oxygen type type. 例如: has acrylic ester can poly 二甲基 silicon oxygen and polyether modified poly 二甲基 silicon oxygen and other. has machine silicon type tool has high temperature resistance, low temperature resistance, physical properties stability, chemical inert property, very low surface force, is commonly used defoamer.

polypropylene (PP) acid type defoamer is through polymer property and molecular weight has selection property versus 容而消泡, use this category of defoamer assessment for gloss effect/influence.

future selection combined defoamer, must to system in foam generate process, system property and concentrated degree, temperature degree and viscosity and other. upper factors for defoamer selection has effect/influence.

evaluation foam control agent main/primary 考虑一 lower several 方面: speed rate; and system versus property; stability property and property ratio. is in formulation in upper factors is versus 矛盾, 例如, and system versus property defoamer its stability property is most 差; property most 差, its speed rate is most fast.

due to coating material Raw Materials and methods more property, defoamer need according to 实际 情况进行 assessment.

1, 按一定 ratio/proportion will comparison defoamer add to in, 放入于玻璃 bottle in, in 震荡仪 in 震动5 separation 钟, meanwhile 拿出观察, according to foam how much 初步确定 defoamer can force; 放置10 separation 钟/30 separation rear, again 次观察 foam high degree, comparison speed degree;

2, use sheet/plate fine degree coating liquid defoamer and system versus property （ has shrink 孔）;

3, system foam remove rear, system degree, has mixed 浊, delamination, and other phenomenon;

4, stability property: semi month rear, heavy 复1, 2, 3步实验, 并确定 defoamer long property

5, 确定添 add amount.