Since 1970s, the application of "a href=" to "//m.pmae.cn/news/list.aspx? Classid=101112107101" > PU adhesive < /a > in shoe making has been very successful. It has become one of the most important adhesives for shoes because of its strong bonding to many kinds of shoe materials.

According to information, [1] is still solvent PU adhesive in 80% of Western Europe and North America. With the increasing environmental protection, the benzene free solvent series (most of which is PU adhesive).

Gradually replace benzene series adhesive.

In recent years, European [2] has removed the series of solvents that do not contain "three benzene" from the list of toxic release substances (TRI) and VOC, which is called "green" solvent. The PU adhesive with its solvent is less stressed by environmental protection.

So up to now, this type of adhesive still plays a very important role in the shoe industry.

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< p > this research work is to synthesize thermoplastic PU elastomers by melting method, and further to prepare adhesive.

Compared with the solution synthesis method, the viscosity value of the product is lower than that of the solution method. Compared with the continuous solution process, it has the characteristics of low equipment investment, simple and mature process control, and convenient replacement of the formula, and has formed the industrial production capacity.

Benzene is not included here, including solvents such as benzene, toluene, xylene and halogenated aromatic hydrocarbons.

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< p > < strong > 1 synthesis (production) part < /strong > < /p >

< p > < strong > 1.1 raw material < /strong > /p >

< p > two phenyl methane diisocyanate (MDI) industrial grade import > /p >

< p > polyhydroxy polyester (PCTA) industrial grade Shandong < /p >

< p > acetone, butanone, ethyl acetate, industrial grade < /p >.

< p > hindered amine light stabilizer industrial grade import > /p >

< p > < strong > 1.2, production and testing equipment < /strong > < /p >

< p > quick mixer speed 300-500 revolutions / minutes, stirring device can lift, capacity 30-50 litres homemade < /p >.

< p > aluminum alloy die surface four fluoride treatment homemade < /p >

< p > 0.5 ton reactor, stirring speed 60-70 revolutions / min. the anchor stirred pulp made in China is < /p >.

< p > 2 ton reactor, stirring speed 60-70 revolutions / min. the anchor stirred pulp made in China is < /p >.

< p > the inside of the polymerizing furnace is a shelf structure, a nitrogen heating zone and a constant temperature heating control device made by oneself. < /p >

< p > knife length 60 cm wide 10 cm homemade < /p >.

< p > broken plastic machine general plastic crusher made in China < /p >

< p > 200 litre oil drum heater, Wuxi Huaneng Electric Heating Equipment Factory < /p >

< p > tensile machine XLL-50 Guangzhou material testing machine factory < /p >

< p > rotary viscometer NDJ-1 type Shanghai balance instrument factory < /p >

< p > < strong > 1.3PU < /strong > a href= //m.pmae.cn/news/list.aspx Classid=101112107108 > > strong > adhesive < /strong > < /a > < > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >

< p > heating and melting of MDI at constant temperature 50 degrees C and constant temperature 60 degree heating and melting of MDI into a stirred tank, stirring at full speed until the viscosity rises violently. Later, the reactants are quickly poured into the aluminum mold plate and sent into the furnace after nitrogen gas. At constant temperature 110-115 degrees, the heat preservation is gathered for 2.5-4 hours. After being taken out, the ambient temperature waits for 20-30 minutes, and the heat is cut into strips. After being naturally cooled, it is sent to the crusher and crushed into granular.

According to the requirement of 12-16% solid content, the reaction kettle with light stabilizer is put into the reactor, dissolved at room temperature, viscosity adjusted, and packed in barrels.

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< p > < strong > 1.4, the determination of bonding splines and bonding strength < /strong > < /p >

The spline can be used to wipe oil or other dirt in a solvent such as acetone, a href= "//m.pmae.cn/news/list.aspx Classid=101112107102" > butanone < /a > or ethyl acetate, etc. the thermoplastic rubber (TPR), rubber, ethylene vinyl acetate copolymer (EVA) material is processed by the corresponding treatment agent (homemade), and then evenly coated with two times on each substrate. After the first time, the rubber is dried at about 60 degrees Celsius for 6-8 minutes. After drying second times, the material is dried for 5 minutes at 60-70 degrees Celsius. After being taken out, it is tightly bonded with a little pressure and stored for 24 hours, according to the standard of GB/T532-1997 (determination of the bonding strength between vulcanized rubber or thermoplastic rubber and fabric). < p > PVC, PU material

You can test the result.

In order to further strengthen heat resistance and permanent strength, 3-5% curing agent (homemade) can be properly added to make it a two liquid adhesive, but the two liquid adhesive should be used in 4-6 hours.

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< p > < strong > 2 results and discussion < /strong > < /p >

< p > < strong > 2.1 the selection of polyisocyanates < /strong > /p >

< p > compared with other types of polyisocyanates, due to the low volatility and toxicity of MDI, and the presence of benzene in the chain, the weak physical stability and poor light stability can be added to < a href= "//m.pmae.cn/" > light stabilizer < /a > fill, which is suitable for the synthesis of thermoplastic PU elastomers.

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< p > < strong > 2.2 the selection of polyhydroxyl polyester < /strong > < /p >

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< p > polyether polyols with polyisocyanate react with polyisocyanate to form polyether type, polyester type and thioether type. The properties of PU elastomers synthesized by their physical and mechanical properties are suitable for polyester. When the molecular weight is between 2160-4680, the molecular weight changes little. However, when the molecular weight is between 1180-2160, the mechanical properties of PU elastomers synthesized by polyester are obviously changed with the increase of molecular weight of polyester, and the molecular weight of polyester diols is about 2000, which is the most suitable [3].

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