Using 效果颜料 for Limitless Coatings Design Possibilities

Effect pigment, UL Prospector, Ronald Lewarchik, 2016年5月: 效果颜料 provide an infinite array of colors 和 effects that enable unlimited design possibilities for 涂料. 这些效果包括灯光闪烁的错觉, 金属反射, interference sparkle 和 color variation 和 luster that changes with the viewing angle 和 light source.

它们被用于各种涂料中, 包括汽车行业, monumental 和 smaller 建筑s as well as other industrial 和 product finishing applications. Pigments may be broadly classified by their ability to reflect light: absorption, 金属和干扰.

Conventional organic 和 inorganic pigments are classified as 吸收颜料, because they absorb certain wavelengths of the incident light that strikes their surface. The sensation of color is produced by the remaining component of the reflected visible light that produces the color we observe.

例如,一个 喹吖酮红色颜料 reflects the portion of the light that produces a red color 和 absorbs the rest of the light energy. 二氧化钛 反射所有的光而不吸收,而 炭黑 吸收一切而不反射任何东西. 因为它们有吸收光线的能力, absorption pigments do not display a metallic luster or iridescence 和 are thus 一维 它们与光相互作用的能力.

金属颜料 由微小的扁平铝片组成, 青铜, 锌, 铜, silver or other metals that reflect light 和 thus create a metallic luster. 这些颜料 两个维 or 金属颜料.

获得材料数据 Interference pigments consist of various layers of, for example, a 金属氧化物 放置在 云母,一种天然矿物质. 照射在这些颜料表面的光线会发生折射, reflected 和 scattered by the layers that make up the pigment. Through a superimposition (or interference) of the reflected rays of light, 创建了一个不断变化的颜色数组, 从反射角上看到的颜色最强烈.

效果颜料 are unique in respect to how they interact with light due to their geometry which is normally a platelet with a high aspect ratio (ratio of width to height). 这取决于具体的技术, 可以创建各种各样的颜色和效果, 如干扰微光, 颜色旅行效果或金属反射.

阅读罗恩文章的其余部分,点击 在这里 前往UL勘探者.

丙烯酸树脂的基本面

丙烯酸树脂的基本面, UL Prospector, Ronald Lewarchik, 4/2016:

涂料使用 丙烯酸树脂 are the leading 聚合物 technology in the 涂料 industry. 从历史上看 醇酸 finishes have held the leading position in 涂料 for decades. 丙烯酸用于建筑涂料, product finishes for original equipment manufacture including 汽车 (OEM) 和 refinish, 以及特殊用途涂料.

丙烯酸树脂主要是以 丙烯酸酯异丁烯酸甲酯 并提供良好的耐候性, 耐水解, 外部应用的光泽和颜色保持. 由于它们的通用性和性能, acrylic 涂料 account for over 25% of all 涂料 和 global sales approaching $25 billion. Acrylic resins can be thermoplastic or thermosett 和 are used in organic solvent born, 水传播的, 粉末和辐射固化涂料

表I -非功能均聚物的Tg
表I -非功能均聚物的Tg

Three broad classes of liquid 涂料 utilizing 丙烯酸树脂 include 热塑性塑料,热固性和水性. Many 丙烯酸树脂 may also include other vinyl monomers such as 苯乙烯 or 醋酸乙烯酯 主要是为了降低成本. Acrylic monomers have a lower Tg than their analogous 异丁烯酸甲酯 monomers (for example compare the Tg for n-butyl 丙烯酸酯 versus n-butyl 异丁烯酸甲酯 see Table I 和 Table II). 如表二所示, the glass transition temperature of the monomers selected for synthesis of a resin can be selected to enhance multiple properties that may include weather resistance, 抗湿性, 氧气渗透, 灵活反应, 治疗和硬度. 除了, acrylics can be functionalized with a variety of monomers to provide improved adhesion to metal, or to react for example with aminoplast or isocyanate crosslinkers.

acrylics_table_2 
表二Tg与物理性能的关系

热塑性丙烯酸聚合物 (TPA) in general have excellent properties including exterior durability. Such resins were widely used in 汽车 OEM 和 Refinish topcoats from the 50’s to the 70’s, but their use has dramatically declined due to the high molecular weight necessary to provide properties, they require a high amount of organic solvent to enable air atomized spray application. 因此,这些涂料适用于约20%重量的固体. Thermoplastic resins typically use a high level of methyl 异丁烯酸甲酯 in their 聚合物 backbone to provide excellent hardness 和 exterior durability.

图一-聚甲基丙烯酸甲酯和聚甲基丙烯酸甲酯的结构 
图一-聚甲基丙烯酸甲酯和聚甲基丙烯酸甲酯的结构

热固性丙烯酸树脂(TSA) are designed with functional monomers to either react with themselves when exposed to heat or moisture, 或与交联剂的交联剂形成交联膜. Thermoset resins as a group are lower molecular weight 和 thus have higher application solids. 一次交联, as a class they offer films with excellent resistance to organic solvents, moisture 和 UV light 和 do not soften appreciably when exposed to moderately high temperatures as thermoplastics do.  An example of 丙烯酸单体 with functional groups that can be used to functionalize acrylic 聚合物s to provide properties such as crosslinking, self-crosslinking, improved adhesion or pigment wetting are provided in Table III.

表III -功能丙烯酸单体 
表III -功能丙烯酸单体

Being able to functionalize an 丙烯酸树脂 with a wide range of reactive moieties provides the ability to tailor the performance of the resin backbone to provide improved adhesion over a variety of substrates, improved pigment wetting 和/or the ability to provide crosslinking or self-crosslinking. 其他 丙烯酸单体 are also available to impart sulfonic acid, 或磷酸功能到丙烯酸树脂.

Being able to functionalize an 丙烯酸树脂 with a wide range of reactive moieties provides the ability to tailor the performance of the resin backbone to provide improved adhesion over a variety of substrates, improved pigment wetting 和/or the ability to provide crosslinking or self-crosslinking. 其他 丙烯酸单体 are also available to impart sulfonic acid, 或磷酸功能到丙烯酸树脂.

氨基甲酸酯功能丙烯酸 can also be made for example by reacting an isocyanate functional acrylic with hydroxypropyl carbamate. Many of the acrylics in the category of functionalized 丙烯酸树脂 are used in 汽车 OEM 和 refinish clearcoats to provide an excellent combination of mar resistance, 耐化学性和光稳定性.

 

阅读罗恩文章的其余部分,点击 在这里 前往UL勘探者.