The hottest two-component polyurethane adhesive II

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Two component polyurethane adhesive (III)

magnetic material adhesive the adhesive resin used for magnetic recording medium and its performance evaluation are shown in the table. These resins are rarely used alone. They are generally mixed and have good comprehensive properties. Generally, resin components are composed of three parts: (1) components containing hydroxyl, such as epoxy resin, acrylic resin, polyester resin, chloroacetic resin, nitrocellulose, etc; (2) Polyisocyanate components that undergo ammoniation and esterification reaction with the above resin, such as biuret type, trimer type polyisocyanate, polyol isocyanate adduct; (3) Elastomer components used for modification, such as thermoplastic polyurethane and nitrile rubber

tape adhesive is required to have the following characteristics:

(1) the magnetic coating can be well bonded to the base film; (2) The magnetic particles are well dispersed in the binder; (3) The coating has good wear resistance; (4) Moderate softness; The huge market demand (5) low friction coefficient; (6) Low electrical resistance; (7) Good drug resistance; (8) The film is not sticky after curing; (9) Wide range of coating temperature; (10) It can be stored for a long time without aging

polyurethane resin has good adhesion to many substrates, excellent wear resistance and durability, and is the main resin in magnetic coatings. Most magnetic coatings contain PU resin. Nowadays, the development trend of magnetic coatings is to simplify the formula. In some cases, the adhesive resin only includes vinyl resin and thermoplastic polyurethane

"TPU". According to the report of only one speed control method, only TPU is used in the foundation nut casting of a magnetic coating formula for a video tape recently

PU resin used for magnetic recording medium is generally a TPU resin with molecular weight of 10000, which is synthesized by the reaction of polybutylene adipate, polyhexanediol adipate, polycaprolactone or phthalic acid polyester polyol with MDI, TDI, HDI, IPDI and other polyisocyanates. The adhesive has single component and two-component types. TPU used for tape adhesive usually has the following properties:

(1) very good solubility in solvent

(2) it can well disperse magnetic particles and has good adhesion to magnetic particles and base film

(3) no adhesion in the contact layer (surface layer)

(4) it has special physical and chemical properties, such as relatively high hardness, wear resistance, elasticity and luster, and very good molecular weight a/-/D4. Distribution

formula example

pu can be used as adhesive in magnetic coating in two aspects

first, polyurethane resin (generally TPU, or the mixture of oligomer polyols such as polyester and diisocyanate) is used alone or in combination with other resins, which is dissolved in solvent as the main component of tape adhesive. Because PU adhesive is well blended with a variety of resins, magnetic particles can be well dispersed in resin solution, have excellent adhesion with various substrates, and the prepared magnetic coating has excellent wear resistance and durability, especially excellent flexibility. Therefore, Pu is included in most magnetic coating formulas

second, most magnetic coating formulations use polyisocyanate as the cross-linking component of the adhesive, that is, to form a two-component magnetic coating. The two-component magnetic coating has limited application period, but the heat resistance and durability of the magnetic recording material are better than those of the single component without crosslinking agent

here are some magnetic coating formulas

1. TPU elastomer is the main component of the resin used as adhesive. Most PU adhesives used for magnetic coating are thermoplastic polyurethane, which makes TPU have excellent mechanical strength and elastic modulus. TPU resin used for magnetic coating adhesive is not completely common with tyu resin used as shoe adhesive, etc., and generally needs special preparation. Tyu prepared from polyester containing side methyl group has good properties

tdk's patented formula is as follows:

mass fraction, so the selected fragmentation situation will be different. Fraction

co-r-fe2o3 400 lubricant 5

polyurethane resin 55 carbon black 5

epoxy resin 30 methyl ethyl ketone 500

nitrocellulose 15 methyl isobutyl ketone 250

dispersant 6 cyclohexanone 25

the deficiency of ordinary crystalline polyester liver true u on the dispersion of magnetic particles can be solved by introducing an s into the molecular chain Q3m, a c02m plasma group. One such magnetic coating formula is as follows:

r-fe2o3 100 polyisocyanate coronatel 3

polyurethane resin 25 solvent several

*pu resin formulas are: 100 parts by mass of poly (e-caprolactone) (mw200) with hoch2ch2c (SO3Na) (CH3) ch2ch2oh as the initiator; 100 parts of poly (hexanediol adipate) (mw200); Mdl24.8 copies; Catalyst dabco0.02 parts. The resin contains ionic groups, which improves the dispersibility of magnetic particles

generally, no catalyst is added to the two-component magnetic coating. However, in order to shorten the curing time and ensure certain applicability, someone has studied the formula with a small amount of catalyst:

co-r-fe2o3 400 stearic acid 4

pu resin (n-2304) 50 barium stearate 4

vinyl chloride vinyl acetate vinyl alcohol 50 methyl ethyl ketone 400

copolymer toluene 500

tertiary amine catalyst 0.2 polyisocyanate (takede E-31) 25

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