Definizione di adesivo

Conoscenza adesiva Sostanze naturali o sintetiche, organiche o inorganiche che possono collegare tra loro due o più parti o materiali attraverso gli effetti di adesione di interfaccia e coesione di sostanze, denominate collettivamente adesivi) Chiamato anche adesivo, comunemente chiamato colla.

① Adhesion (adhesion): refers to the state where two surfaces are held together by chemical, physical, or both forces

② L'adesivo deve prima aderire alla superficie dell'aderente. Ciò è dovuto all'adesione tra le due fasi, che è derivata dalla forza di legame secondaria o primaria.

Coesione: Cioè, lo stato di ciascuna particella in una singola sostanza è combinato dalla valenza primaria (inclusa la valenza ionica, covalente, coordinazione, metallo, ecc.) E secondaria (inclusa van der Waals, legame idrogeno). La forza coesiva dell'adesivo è correlata a fattori come la forza intermolecolare, la massa molecolare relativa, il grado di reticolazione, la cristallizzazione e l'entanglement molecolare.

Requisiti dell'adesivo Conoscenza dell'adesivo

① Indipendentemente dallo stato, dovrebbe essere liquido durante il rivestimento

② La superficie dell'aderente può essere completamente stesa e completamente bagnata

③ Must be able to transform the liquid into a solid or gel state in some way to form a tough and stable glue layer

④ It should have a certain strength after curing. Able to connect reliably, transfer stress and resist damage

⑤ Can withstand temperatures above 0 ° C and withstand a certain period of time

Classification of adhesives

Classified by appearance: solvent-based emulsion type (aqueous); paste or paste; solid type; film type.

According to the curing method: water-based evaporation type, solvent evaporation type, hot melt type, chemical reaction type, pressure sensitive type.

Basic composition of adhesive

The basic composition of adhesives: the components of adhesives include base materials, curing agents, solvents, plasticizers, fillers, coupling agents, crosslinking agents, accelerators, tougheners, tackifiers, thickeners, diluents, Anti-aging agent, polymerization inhibitor, flame retardant, initiator, photosensitizer, defoamer, preservative, stabilizer, complexing agent, emulsifier.

Type of base material: The base material is the main component of the adhesive, the main agent or the main polymer, and plays an adhesive role. According to the chemical composition, the sources of the base material are inorganic compounds and organic compounds. Organic compounds are polymer binders for polymer synthesis.

① Common organic compounds: thermosetting synthetic resins: phenolic resin, epoxy resin, amino resin, polyurethane resin, unsaturated polyester and acrylic resin

② Thermoplastic synthetic resin: rubber base material, natural polymer material, water-based latex, base material

③ Rubber base adhesive

Selection principle of adhesive base material: According to the application object, application occasion and application performance of the adhesive. At the same time, the molecular structure of the molecular base is closely related to the adhesion properties.

① The polarity of polymer materials is related

② Crystallization of polymer materials

③ Molecular weight of polymer materials

Curing agent (hardening agent): The raw material in the ground state undergoes chemical reactions to undergo polymerization, polycondensation, or cross-linking reactions to change into linear polymers or network polymers. It is a substance that has mechanical strength and stability.

The role of solvents:

① Polymerization reaction medium: moderate reaction and easy temperature control

② Dissolving base material: preparing solvent-based adhesive knowledge

③ Thinner: Dilute the adhesive to a certain viscosity, which is good for wetting and coating.

④ Adjust the volatilization rate of the adhesive

⑤ Prevent gel, used to increase storage stability

⑥ Surface cleaning agent before bonding

⑦ Direct bonding, some plastics

⑧ Reduce costs and increase benefits