Classification of tackifiers According to the different solubility in ABA-type block polymer thermoplastic elastomer, commonly used tackifiers can be divided into three categories.
The solubility parameter of the first type is generally low, and it is only compatible with nonpolar rubber phase and petroleum asphalt. Aliphatic and alicyclic petroleum resins, rosin and hydrogenated rosin resins, terpene resins all belong to this category, which can reduce the elasticity, modulus and bonding strength of self-adhesive modified asphalt, and give the self-adhesive modified asphalt initial adhesion and peeling strength.
Viscosity enhancers are divided into water-based and oil-based. The water-based tackifier includes water-based tackifier, water-based tackifier resin and water-based tackifier powder. Oily ones include tackified rosin resin and modified rosin resin.
As a kind of adhesive, tackifier mainly improves the initial adhesion and adhesion of products; Used in coatings to improve the adhesion with the substrate! The concept of tackifier function Although natural rubber is sticky, the adhesive strength produced by rubber alone is still insufficient for many applications.
Most commercial elastomers lack adhesion, both to themselves and to other surfaces.
Therefore, in order to increase their viscosity, resin tackifiers are needed.
A large number of adhesive and solvent systems, especially when used as contact adhesives, require the use of specific kinds of tackifying resins.
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The relative molecular weight of common tackifiers is 200 ~ 1500, which generally has a large and rigid structure.
They are thermoplastic and usually amorphous glass bodies at room temperature.
They have a wide softening point, ranging from liquids at room temperature to fragile solids with melting points as high as 90℃.
They are usually completely soluble in aliphatic hydrocarbons, aromatic hydrocarbons and many typical organic solvents.
Early typical tackifying resins used in the adhesive industry can be found in Irving.
Skiest's "manual"
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Adhesive "
In "resin"
for
Rubber-based
Annex "chapter; For the relevant American patent documents from 1976 to 200 1, please refer to the corresponding questionnaire at the back of this chapter.
From the point of view of viscosity, tensile strength, color retention and oxidation embrittlement resistance, the selection of tackifying resin will affect the quality of adhesive.
Unmodified gum and wood rosin can be converted into esters, which are sticky at first, but the aging resistance is poor after gluing.
Rosin esters stabilized by hydrogenation or polymerization are resistant to oxygen corrosion and have the best comprehensive properties when used as adhesives.
For example: Staybe 1ite.
ester
10 or forum
185 (hydrogenated rosin glyceride), Penta 1yn
H or for 1
L05 (ester of hydrogenated rosin).
The lower softening point resin has a greater viscosity increase limit effect than the lower softening point resin, but this effect can only be obtained at high concentration.
The tensile strength will decrease with the increase of tackifier concentration, and the reduction rate of different tackifiers is also different.
Styrene-butadiene rubber system Styrene-butadiene rubber system itself has poor viscosity, when enough Penta 1yn
The tackifier produces viscosity and a second phase appears in the film.
When the concentration of tackifier is 60% ~ 65%, the viscosity reaches the maximum.
However, for several different kinds of anti-crystallization soft chloroprene rubber, the relationship between softening point and viscosity of the above tackifier is not necessarily correct.
Like natural rubber, high-viscosity rubber film will lose its viscosity and two-phase characteristics when heated continuously at 93℃.