Two component polyurethane adhesive IV

2022-06-22
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Two component polyurethane adhesive (IV)

2. radiation curable modified PU adhesive

some patents have reported radiation curable magnetic coatings. The modified PU adhesive containing unsaturated bonds is coated into a thin layer on the base film, which is suitable for electron beam radiation curing. In most cases, the adhesive resin is composed of acrylic modified polyurethane resin, and sometimes multi-functional crosslinking agent is added. TPU resin is generally polyester type, and a small amount of it uses polyether as raw material

a magnetic coating formula that can be cured by electron beam is:

co-r-fe2o3 80 pentaerythritol acrylate 5

acrylic modified PU resin 15 methyl ethyl ketone 200

wherein the preparation formula of acrylic modified PU resin is:

ppg-10251000 2-hydroxyethyl methacrylate 65

n- (2-hydroxy-1-propyl) Diethanolamine 163 hmdi 590

3. PU adhesives for other types of tapes

BASF company of Germany and other companies researched and improved the added value of products to prepare lotion PU adhesives for magnetic coatings, including the preparation formula of a PU lotion adhesive

pba polyester mw1000 210 tetrahydrofuran 1760

1, 4-butanediol 23.1 organotin 1

trimethylolpropane 1.34 mercaptopropionic acid 55.2

epikele 828-diacrylate 207.2 triethylamine 60.6

mdl 312.5 acetone 31

the preparation method is as follows: polyester, small molecular glycol, trialcohol, epoxy acrylate and MDI are heated and reacted in tetrahydrofuran, and the catalyst is added dropwise, followed by mercaptopropionic acid Acetone mixture of triethylamine is dispersed in water after 45min, and the solvent is evaporated to obtain concave lotion adhesive

add 1.5% silicone oil to the above lotion and mix it evenly. Add it to the ammonia water dispersion of r-Fe2O3 and mix it evenly. Apply it on the P-based film due to its technical advantages. Dry it and get the magnetic recording tape. Some people use polyurethane adhesive to apply a layer of coating on the back of the magnetic coated tape to improve the wear resistance of the tape and obtain a good friction coefficient. The coating consists of PU adhesive and non-magnetic powder. A coating for this purpose is composed of polyurethane resin (nippo-ran2301), polyisocyanate (coronatel), calcium carbonate powder and methyl ethyl ketone

ink adhesive

polyurethane resin has excellent flexibility, adhesion and dispersion to pigments. It can be used as an adhesive for photographic intaglio and plate printing inks on plastic or metal surfaces

it is essentially different from PU resins used in other fields. PU for inks should have the following requirements: (1) the most basic is solubility. Considering the compatibility with pigments and other resins and the volatility of inks to solvents, alcohol is a mixed solvent; (2) The dry resin surface is not sticky; (3) The viscosity of PU adhesive made of PU resin dissolved in mixed solvents should be low, and its strength should be high after film formation

(4) the adhesive should have good adhesion to the substrate with smooth surface. Long fiber reinforced mixed fiber is an ideal material, so crystalline TPU resin can not be used generally

PU resin used for ink adhesives is generally prepared from polyester or polyether polyols, alicyclic diisocyanates and diamine/diol chain extenders, with a molecular weight of tens of thousands. In order to dissolve in alcohol and improve the film strength, adhesion with plastics or other substrates and dispersion of pigments, urea bonds are generally introduced into PU resin to form polyurethane urea resin (PUU). The polyurethane adhesive used for printing ink is mainly composed of single component

a patent of Nippon ink chemical industry Co., Ltd. of Japan gives a method for manufacturing PU ink adhesive I: a prepolymer solution with a solid content of 80% is prepared by reacting polybutylene terephthalate glycol with methyl ethyl ketone. 1350 parts of the prepolymer solution react with 68 parts of Isophorone diamine PD and 12.9 parts of Diisobutylamine in 1470 parts of methyl ethyl ketone at 40 ℃ for 1 hour to obtain a PUU solution with a solid content of about 40%, The molecular weight of PUU is 19200. This solution is treated with 77 parts of 75% HDI/P adduct (NCO content 12%) at 80 ℃ for 3h, and then mixed with methyl ethyl ketone and isopropanol. The viscosity of the 30% concentration resin solution adhesive is 1050 MPa · s at 25 ℃. An ink composition contains 30 parts of PU adhesive, 30 parts of titanium dioxide pigment, 10 parts of isopropanol and 30 parts of methyl ethyl ketone. It is printed on PE, PP and PET films, and the adhesive strip stripping test is carried out. It is found that the printing layer of the ink has a retention value of ≥ 90%. When mixed with polyisocyanate crosslinking agent, this ink has a long service life. For example, when 3% crosslinking agent is added, the viscosity increase rate is less than 10% after 40 bar storage for 24h

a PU resin for ink adhesive (color developing agent) developed by Sanyo Chemical Co., Ltd. of Japan is prepared from PBA polyester (mw1500), IPDI, IPDA and diethanolamine. Its softening point is 120 ℃, a and 100% modulus is 3 MPa. Due to the introduction of urea bond and amino group, the intermolecular hydrogen bond force is greatly increased, and the cohesion strength of the resin and the adhesion to the film are improved. The plastic film printing ink prepared by 30 parts of the resin, 50 parts of titanium dioxide and several parts of mixed solvent has good printing effect on PP, pet and nylon films, and the printing layer is resistant to heat, grease and adhesion

it is also composed of poly (adipic acid) - (3-methyl-1,5-pentanediol) ester glycol 0.5mol, poly (tetrahydrofuran ether glycol) (mw2000) 0.5mol, hwmdl2.5mol and ipdll When 5mol of PUU resin is used as ink adhesive, the pigment can be more evenly dispersed in the ink and have better adhesion to the substrate

polyurethane ink is a high-grade ink. Although it has a wide range of applications, it is generally used as a special ink

a typical example is that polyamide ink is widely used in domestic plastic film printing ink. This general-purpose ink has good printing performance, and the tape stripping test is also qualified. However, if the printing surface is subject to subsequent composite processing, that is, transparent plastic film is used to cover the printing surface to protect the printing layer, and laminated film for composite flexible packaging is manufactured, it is found that the composite fastness is greatly reduced compared with the unprinted plastic film. The reason is that the polyurethane adhesive used in the composite process of flexible packaging composite film has an impact on the ink layer. In the stripping test of composite film, the ink layer is easy to peel off from the plastic base film, while the ink layer is firmly combined with the adhesive layer, and the adhesive layer is basically not damaged. The ideal peeling failure is that a small part of the ink layer is peeled off and the adhesive layer is damaged. Therefore, special reverse printing inks, such as polyurethane ink, chlorosulfonated polyethylene ink and chlorinated polypropylene ink, should be used for this reverse printing occasion. From the perspective of resin preparation, PU ink can be easily prepared on a small scale as long as isophorone diisocyanate, isophorone diamine and other raw materials can be obtained, while the preparation of chlorinated polypropylene resin requires chlorination process, which may cause environmental pollution and have certain risks. It is said that some high-performance inks and ink resins need to be imported

crumb glue

the properties of recycled boards such as particleboard are mainly related to the crumbs and the adhesives used, and more depend on the properties of adhesives. Compared with the recycled board made of PF,.Uf and other adhesives, the recycled board made of adhesives and wood chips has better performance

German roffael et al. Compared the water absorption of particleboard bonded with MDI adhesive, up adhesive and PP adhesive under different relative humidity (nu) at 20 ℃, and found that the Particleboard Made with MDL adhesive has lower water absorption under high RH environment. German roffael has some advantages when using coarse MDL as particleboard adhesive compared with PF adhesive through experiments, such as the density of the board made with coarse MDI can be reduced by 10%-15%, But it still has higher strength and shorter pressing time. Deppe pointed out that under the production conditions of using trialdehyde adhesive, particleboard with different adhesives at 20 ℃ has strict requirements on the moisture content of raw materials. The comparison of water absorption under different relative humidity, even if the moisture ratio is more than 0.5%, may cause cracks in the board, which is caused by excessive steam pressure during heating and molding. This problem does not exist when PU adhesive is used. He also reported that the particleboard bonded with isocyanate adhesive has similar weather resistance to the PP board. The test shows that using coarse MDI with the mass of sawdust of 5% ~ 6% as the adhesive can produce satisfactory performance, while using conventional adhesive requires 10%, which reduces the cost difference between PP adhesive and isocyanate adhesive. As for the broken materials of crop straw and flax straw, generally speaking, the properties of the boards made by using PP or up adhesive are not satisfactory, while the coarse MDI adhesive is more appropriate

sachs respectively used coarse MDI and commercially available PF resin as adhesives to make particleboard samples. The amount of adhesive was the same, the amount of paraffin was 1%, the molding temperature was 170 ℃, and the thickness of particleboard was 16mm. The properties of the two kinds of boards were compared

through practice, MDI series adhesives (including coarse MDI, i.e. papl) are more suitable as wood processing adhesives and adhesives than TDI series. Sachs manufactured three-layer test particleboard with the same amount of these two types of adhesives

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