CN1084541A - A kind of method that improves rubber and Bond Strength and resistance to boiling water thereof - Google Patents

Abstract

The present invention uses epoxy resin/phenolic-formal film two-step method to improve the bonding strength and boiling water resistance between metal and rubber. After grinding, degreasing and cleaning the metal surface, first coat a layer of epoxy resin, and then stick it immediately. Apply phenolic-formal film and bond with rubber, the bonding strength can reach 60-90kg/cm ² , and the retention rate can reach 100% after boiling in water for 7 days, which can meet the requirements of long-lasting bonding of rubber and metal under high temperature and humidity need.

Description

This invention relates to improvements in bonding techniques.

Because the polarity of rubber and metal surface is very different, so its bonding is more difficult, the existing adhesives are phenolic, epoxy, polyurethane, acrylic esters with rubber properties, Japanese patent 75-35935 and Japanese publication 73-48531 published phenolic -Acetal glue is also an adhesive that can be used for bonding metal and rubber, but none of them can meet the requirements of working in a high-temperature and high-humidity environment and have a large bonding strength.

The purpose of the present invention is to solve the above-mentioned difficulties, and propose a bonding method that satisfies the high-temperature and high-humidity environment and has relatively high tensile shear strength, and an improved adhesive.

The present invention is realized in the following way: first coat epoxy glue on the metal surface, then coat or paste a layer of phenolic-acetal film, then bond with rubber, and then pressurize and heat to cure. Pressurize at 0.8-3kg/cm ² , heat at 155-180°C, heat-preserve and cure for 10-30 minutes.

Common grades of epoxy glue can be used, and it is best to use modified ones. Its basic components are (weight ratio. W): E-44 epoxy resin: 100; curing agent: 20-40; polysulfide rubber: 20-30 Accelerator: 6~10; The basic components of phenolic resin-formal are (W): phenolic resin: 50~125;

Bonding metal and rubber through the above process can significantly improve the boiling water resistance (temperature resistance), and the tensile shear strength has little effect. Using modified epoxy and ordinary grades of phenolic-formal can make the tensile shear strength reach 60 ～90kg/cm ² , the strength remains above 95% after 7 days of boiling water (tensile shear strength test: according to the standard of HG4-853-76 of the Ministry of Chemical Industry), and the service life of the bonding method in the prior art is increased by 1 to 5 times . The method of the invention is simple and has obvious effects in use, can be used for bonding various metals and rubbers, especially synthetic rubbers, and can maintain strength under high temperature and high humidity.

Below by embodiment the present invention will be further described:

Typical ratio of modified epoxy A (weight ratio):

Ordinary epoxy A' (such as E-44 grade): 100,

Polyene polyamine: 45～55

Polysulfide rubber 20～30 DMP-30 6～10

Inorganic filler 20～40

The inorganic filler is quartz powder, calcium carbonate powder or metal oxide.

Phenolic-formal glue B is prepared according to the following ingredients and preparation methods: phenolic resin and polyvinyl formal are mixed in a weight ratio of 50-125:100, dissolved in toluene/ethanol mixed solvent, and the solvent is volatilized, and the width is about 2cm. Adhesive films with a thickness of 0.5-1.0mm can also be selected from similar FSC-3 grades or Japanese Redux-Film C.

Example 1: Comparison of the bonding between steel and neoprene: After the metal surface is roughened with sandpaper and cleaned with acetone, a thin layer of modified epoxy resin Al is applied, and a layer of B glue is immediately attached, and then polished and removed. Grease and neoprene after cleaning are combined, pressurized at 1.5kg/cm ² , cured at 160°C for 20 minutes, and the bonding strength is compared as follows:

Rubber species Uncooked shear strength (kg/cm ² ) Shear strength after boiling for 150h (kg/cm ² ) Epoxy resin A 30 twenty two Agricultural Machinery No. I Glue (Epoxy Glue) twenty four 14 B glue (similar to FSC-3) 28 Automatic fall off XY－401 (Neoprene Adhesive) 17 Automatic fall off Agricultural Machinery No. I Rubber + B 48 (The rubber interface layer falls off) 30 A+B (this invention) 78 (rubber body broken) 75 (rubber body broken)

Example 2: Using the process of the present invention, pressurize at 1.0kg/cm ² , cure at 170°C for 10 minutes, and compare the strength of bonding steel-styrene-butadiene rubber: Rubber Uncooked shear strength (kg/cm ² ) Shear strength after boiling for 150h (kg/cm ² ) Epoxy A 25 18 B glue (similar to FSC-3) twenty one Automatic fall off A+B (this invention) 56 (rubber body broken) 58 (rubber body broken)

Example 3: The present invention is bonded with styrene-butadiene rubber-lead, pressurized at 2.0kg/cm ² , kept at 155°C for 15 minutes, and compared with A and B glues as follows:

Rubber Uncooked shear strength (kg/cm ² ) Shear strength after boiling for 150h (kg/cm ² ) Epoxy A 28 20 B glue twenty four Automatic fall off A+B invention 62 (rubber body broken) 60 (rubber body broken)

Example 4: The present invention is bonded to nitrile-steel, pressurized at 1.5kg/cm ² , kept at 175°C for 15 minutes, and compared with glues A and B: Glue Uncooked shear strength (kg/cm ² ) Shear strength after boiling for 150h (kg/cm ² ) Epoxy A 37 26 B glue (FSC-3) 43 Automatic fall off Epoxy (A) and polymerized phenol-formal prefabricated liquid sinking glue (similar to E4) 40 36 J-28 (phenolic-nitrile adhesive) 64 (Nitrile rubber body break) 30 Agricultural Machinery No. I Rubber + B 62 (rubber body broken) 48 (rubber surface peeling off) A+B (this invention) 85－95 (Nitrile rubber complete body break) 90-100 (rubber body broken)

Example 5: The effect of bonding stainless steel according to the present invention is similar to the results obtained in the above examples. The invention is used for the bonding of stainless steel and nitrile rubber in engineering asphalt conveyor belts of Yangzi Ethylene Company. Polish the surface of the stainless steel with sandpaper, clean it with acetone, apply epoxy resin (A), and immediately paste the phenolic-formal film (B). After waxing, grinding, and cleaning the surface with acetone, the NBR is glued together and pressurized. 2kg/cm ² , heated to 170°C and kept for 10 minutes, then cooled to room temperature. After nine months of continuous operation of the conveyor belt, the adhesive interface has not fallen off. However, under the same conditions, the conveyor belt bonded with Redux-Film C glue (similar to B) made in Japan, the interface will fall off after one month of operation, and it can last for 3-6 months at most after repairing.

Commonly used adhesive grades refer to "Chemical Product Application Manual", Shanghai Science and Technology Press (1990), "Practical Adhesive Handbook", Shanghai Science and Technology Literature Publishing House", (1987), "Chemical Product Handbook", Chemical Industry Press Society (1985).

Claims (4)

1, a kind of method that improves rubber and Bond Strength and resistance to boiling water thereof is characterized in that earlier coating epoxy glue in the metallic surface, pastes one deck phenolic aldehyde-formal glued membrane again, then with rubber adhesion, after pressurization, heating cure.

2, by the described method of claim 1, it is characterized in that the 0.8～3kg/cm that pressurizes ², heat 155～180 ℃, heat preservation solidification 10～30min.

3,, it is characterized in that epoxy glue constitutes (W) with following proportioning by claim 1 or 2 described methods: E-44 Resins, epoxy, amine curing agent 45～55, thiorubber 20～30, DMP-30,6～10, and mineral filler 20-40.

4,, it is characterized in that phenolic aldehyde-formal constitutes (W) with following proportioning: resol by claim 1 or 2 described methods: 50～125, vinyl-formal resin: 100.