环氧树脂结构胶的分类及其特性 epoxy resin adhesives

环氧树脂胶粘剂的品种很多，其分类的方法和分类的指标尚未统一。

一、按胶粘剂形态分类

无溶剂型胶粘剂、(有机)溶剂型胶粘剂、水性胶粘剂(又可分为水乳型和水溶型两种)、膏状胶粘剂、薄膜状胶粘剂(环氧胶膜)等。

二、按固化条件分类

1．冷固化胶(不加热固化胶)。又分为：

低温固化胶，固化温度<15℃；

室温固化胶，固化温度15—40℃。

2．热固化胶。又可分为：

中温固化胶，固化温度约80—120℃；

高温固化胶，固化温度>150℃。

3．其他方式固化胶，如光固化胶、潮湿面及水中固化胶、潜伏性固化胶等。

三、按胶接强度分类

1．结构胶，抗剪及抗拉强度大，而且还应有较高的不均匀扯离强度，使胶接接头在长时间内能承受振动、疲劳及冲击等载荷。同时还应具有较高的耐热性和耐候性。通常钢-钢室温抗剪强度>25MPa，抗拉强度≥33MPa。不均匀扯离强度>40kN/m。

2．次受力结构胶，能承受中等载荷。通常抗剪强度17—25MPa，不均匀扯离强度20—50kN/m。

3．非结构胶，即通用型胶粘剂。其室温强度还比较高，但随温度的升高，胶接强度下降较快。只能用于受力不大的部位。

四、按用途分类

1．通用型胶粘剂。

2．特种胶粘剂。如耐高温胶(使用温度≥150℃)、耐低温胶(可耐—50℃或更低的温度)、应变胶(粘贴应变片用)、导电胶(体积电阻率10-3～10-4Ω·cm)、密封胶(真空密封、机械密封用)、光学胶(无色透明、耐光老化、折光率与光学零件相匹配)、耐腐蚀胶、结构胶等。

五、其他分类

也可按固化剂的类型来分类，如胺固化环氧胶、酸酐固化胶等。还可分为双组分胶和单组分胶，纯环氧胶和改性环氧胶(如环氧-尼龙胶、环氧-聚硫橡胶胶、环氧-丁腈胶、环氧-聚氨酯胶、环氧-酚醛胶、有机硅环氧胶、丙烯酸环氧胶等)。

环氧类胶粘剂主要由环氧树脂和固化剂两大部分组成。为改善某些性能，满足不同用途还可以加入增韧剂、稀释剂、促进剂、偶联剂等辅助材料。由于环氧胶粘剂的粘接强度高、通用性强，曾有“万能胶”、“大力胶”之称，在航空、航天、汽车、机械、建筑、化工、轻工、电子、电器以及日常生活等领域得到广泛的应用。

There are many kinds of epoxy resin adhesives, but the classification method and index have not been unified.

1、 Classification by adhesive form

Solventless adhesive, (organic) solvent adhesive, water-based adhesive (also can be divided into water emulsion type and water-soluble type), paste adhesive, film adhesive (epoxy film), etc.

2、 Classification by curing conditions

1. Cold curing adhesive (without heating curing adhesive). It is also divided into:

Low temperature curing adhesive, curing temperature < 15 ℃;

Room temperature curing adhesive, curing temperature 15-40 ℃.

2. Heat curing adhesive. It can also be divided into:

The curing temperature is about 80-120 ℃;

High temperature curing adhesive, curing temperature > 150 ℃.

3. Other methods of curing adhesive, such as light curing adhesive, wet surface and water curing adhesive, latent curing adhesive, etc.

3、 Classification by adhesive strength

1. Structural adhesive has high shear strength and tensile strength, and also has high uneven pulling strength, so that the adhesive joint can withstand vibration, fatigue, impact and other loads in a long time. At the same time, it should have high heat resistance and weather resistance. Generally, the shear strength of steel steel at room temperature is more than 25MPa, and the tensile strength is more than 33mpa. The uneven pulling strength is more than 40 kn / m.

2. Secondary stressed structural adhesive can bear medium load. Generally, the shear strength is 17-25mpa, and the uneven pull-off strength is 20-50kn / m.

3. Non structural adhesive, i.e. general adhesive. Its room temperature strength is still relatively high, but with the increase of temperature, the bonding strength decreases rapidly. It can only be used for parts with little stress.

4、 Classification by use

1. General adhesive.

2. Special adhesive. For example, high temperature resistant adhesive (use temperature ≥ 150 ℃), low temperature resistant adhesive (can bear - 50 ℃ or lower temperature), strain adhesive (for pasting strain gauge), conductive adhesive (volume resistivity 10-3 ~ 10-4 Ω· cm), sealant (for vacuum sealing and mechanical sealing), optical adhesive (colorless transparent, light aging resistant, refractive index matching with optical parts), corrosion resistant adhesive, structural adhesive, etc.

5、 Other categories

It can also be classified according to the type of curing agent, such as amine curing epoxy adhesive, anhydride curing adhesive, etc. It can also be divided into two-component glue and one-component glue, pure epoxy glue and modified epoxy glue (such as epoxy nylon glue, epoxy polysulfide rubber glue, epoxy NBR glue, epoxy polyurethane glue, epoxy phenolic glue, silicone epoxy glue, acrylic epoxy glue, etc.).

Epoxy adhesive is mainly composed of epoxy resin and curing agent. In order to improve some properties and meet different purposes, auxiliary materials such as toughening agent, diluent, accelerant and coupling agent can also be added. Because of its high adhesive strength and versatility, epoxy adhesive has been called "all-purpose adhesive" and "energetically adhesive", and has been widely used in aviation, aerospace, automobile, machinery, construction, chemical industry, light industry, electronics, electrical appliances, daily life and other fields.