JPS61174282A - Adhesive for anticorrosive tape - Google Patents

Abstract

PURPOSE:To provide an adhesive for an anticorrosive tape having an excellent adhesion which does not require the use of any solvent and heating at the time of using it and can be used in a wide temperature range, by mixing a liquid diene polymer having a hydroxyl group with a polyisocyanate compound and a bituminous substance. CONSTITUTION:A liquid diene polymer (A) having at its terminal a hydroxyl group and having a number-average molecular weight of about 300 - about 25,000 (e.g. butadiene homopolymer or butadiene-styrene copolymer) is mixed with a polyisocyanate compound (B) (e.g. tolylene diisocyanate) and a bituminous substance (C) (e.g. straight asphalt or tar) in such an amount as will provide 1.5-10 equivalents of the isocyanate group contained in the component (B) per equivalent of the hydroxyl group contained in the component (A), to thereby obtain a desired adhesive for an anticorrosive tape. The above-obtained adhesive exhibits an excellent adhesion by merely applying it to an anticorrosive tape made of polyethylene etc., and wrapping the tape around steel pipes etc.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an adhesive for anticorrosion tape, and more specifically, it does not require solvents, heating, etc. during use, and has a wide operating temperature range.
This invention relates to an adhesive for anticorrosive tapes that has good adhesion over a wide temperature range.

[Prior Art and Problems to be Solved by the Invention] Conventionally, corrosion prevention has been carried out by wrapping tape around the surface of steel pipes, especially underground steel pipes for water, gas, etc. pipes. Plastics such as polyethylene have been mainly used for this anticorrosion tape, and butyl rubber has been used as the adhesive. However, when using this Butylgo J as an adhesive for anticorrosion tape, Hensen. It was necessary to use it as a solution by dissolving it in an a-containing solvent such as toluene, or to use it by heating and melting it. In addition, there is room for improvement in adhesion, as the adhesion is insufficient particularly at high temperatures and peeling occurs during summer.

In order to develop an adhesive for anticorrosive tapes that eliminates the above-mentioned drawbacks, the inventors of the present invention have made extensive studies and found that a composition made by combining specific substances does not require solvents, heating, etc., and can be used as an adhesive. It was found that the present invention was successful, and the present invention was completed.

[Failure to solve the problem]

That is, the present invention is an adhesive for anticorrosive tapes comprising a liquid diene polymer containing hydroxyl groups, a polyisocyanate compound, and a bituminous substance.

In the present invention, the hydroxyl group-containing liquid diene polymer has a hydroxyl group at the molecular end and has a number average molecular weight of 300 to 2.
5000, preferably 500 to 100 (10).These liquid diene polymers include diene polymers having 4 to 12 carbon atoms, diene copolymers, and furthermore, these diene polymers having 4 to 12 carbon atoms. - and an α-olefinic addition polymerizable monomer having a carbon number of 2 to 22.

Specifically, butadiene homopolymer, isoprene homopolymer, butadiene-styrene copolymer.

Examples include butadiene-isoprene copolymer, butadiene-acrylonitrile copolymer, butadiene-2-ethylhedyl acrylate copolymer, butatsuene-n-occudecyl acrylate copolymer, and the like.

Next, the polyisocyanate is an organic compound having two or more isocyanate groups in one molecule, and has an isocyanate group reactive with the water group of the hydroxyl group-containing liquid diene polymer. Such polyisocyanate compounds are well known, and may be in the form of a prepolymer having isocyanate groups at the ends obtained by reacting a polyol with polyisocyanate-1. Examples of polyisocyanate compounds include the customary aromatic, aliphatic and cyclic ones, such as tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, liquid modified diphenylmethane diisocyanate, polymethylene polyphenylisocyanate.

Examples include xylylene diisocyanate, cyclohexyl diisocyanate, cyclohexanephenylene diisocyanate, naphthalene-1,5-diisocyanate, isopropyrhenzene-2,4-diisocyanate, and addition reaction products of polypropylene glycol and tolylene diisocyanate.

Further, the bituminous substance is not particularly limited, and examples thereof include stranded asphalt, semi-build asphalt, blown asphalt, tar, and mixtures thereof. Preferably, straight asphalt or Straight asphalt and other asphalts should be used together.

The adhesive for anticorrosion tape of the present invention consists of the above three components, and although there are no particular restrictions on the amount of the compounded components, the equivalent ratio of the isocyanate groups contained in the polyisocyanate compound to the hydroxyl groups contained in the hydroxyl group-containing liquid diene polymer is such that the isocyanate groups are the same. /hydroxyl group=1.5 to 10.0, preferably 1.5 to 6.0. When this equivalent ratio is less than 1.5, the viscosity of the adhesive becomes high and coating becomes difficult, and when it exceeds 10.0, the curing speed of the adhesive becomes slow, which is not preferred in practice.

Further, the amount of the bituminous substance blended is 30 to 1000 parts by weight, preferably 50 to 500 parts by weight, based on 100 parts by weight of the hydroxyl group-containing liquid diene polymer.

The adhesive for anticorrosion tape of the present invention basically consists of the above three components, but other additives can be added as necessary. For example, in order to improve the physical properties of the composition, 1.
4-butanediol, trimethylolpropane, ethylene glycol, ethylene oxide of bisphenol A 3
Molar adduct, N.

N-bis(2-hydroxypropyl)aniline and the like can be added. In addition, softeners such as dioctyl phthalate as viscosity modifiers; aromatic, naphthenic, and paraffinic softeners; tackifying resins to adjust adhesive strength; Fillers such as calcium, clay, and talc and various stabilizers can also be added. Here, the tackifying resin is argylphenol resin or terpene resin.

Terpene phenolic resin, xylene formaldehyde resin, rosin, hydrogenated rosin, coumaron resin.

Examples include aliphatic and aromatic petroleum resins. In addition, storage stabilizers such as hendyl chloride F, curing accelerators such as dibutyltin dilaurate, stannous octoate, and polyethylene diamine, storage stabilizers such as hendyl chloride, anti-aging agents, and antifoaming agents to improve weather resistance. A silicon compound or the like can be added as an agent.

The adhesive for anticorrosion tape of the present invention can be obtained by mixing and kneading the above raw materials. Kneading may be carried out by a commonly used method, for example using a Banbury mixer or the like at 0 to 120°C, preferably 10 to 90°C.
This can be carried out by melt-kneading at a temperature of 0.5 to 48 hours, preferably 6 to 16 hours. Preferably, after heating and stirring the hydroxyl group-containing liquid diene polymer and the bituminous material,
The adhesive for anticorrosion tape of the present invention is obtained by cooling, then adding and kneading a heated and melted polyisocyanate compound, and then cooling.

The adhesive for anticorrosion tape thus obtained is a moisture-curable prepolymer, and is thought to form a urea bond due to moisture in the air and polymerize into a cured product.

〔Effect of the invention〕

This anticorrosion tape adhesive exhibits good adhesion when wrapped around a steel pipe or the like by simply applying it to an anticorrosion tape made of polyethylene or the like without any special treatment. In this application, the adhesive of the present invention does not require the use of organic solvents such as Hensen or toluene, nor does it require heating and melting, and is excellent in workability. The obtained cured product has high adhesive strength and has strong adhesive properties over a wide temperature range from low to high temperatures.

Therefore, the adhesive for anticorrosive tapes of the present invention is extremely useful as an adhesive for anticorrosive tapes for steel pipes for gas, water, etc.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Liquid polybutadiene having a hydroxyl group at the end (manufactured by Idemitsu Petroleum Science Co., Ltd., rPoly bd R-45HTj, hydroxyl group-containing io, 79 meq/g, number average molecule i
i2800) 100g and straight asphalt (
Penetration 150/200) 452.6 g 17! Place in a separable flask, l ts* Hg, 80°C.
Dehydration was performed by heating for 1 hour. Thereafter, the mixture was cooled to 40°C, and 31.4 g of 4,4'-diphenylmethane diisocyanate heated and melted at 60°C was added, stirred vigorously, and maintained at 60°C for 1 hour. Next, after heating to 80°C and stirring for 3 hours, dibutyltin dilaurate 0.
After adding 5 g of the mixture and stirring for another 15 minutes, the mixture was cooled to obtain an adhesive for a waterproof sheet. This product was black, had a viscosity of 1200 poise/25°C, and had an isocyanate group content of 0.9% by weight.

Apply this adhesive to anti-corrosion tape and heat it to a steel plate at a temperature of 25℃.
It was cured for one week at a humidity of 60%. At this time, the 180° vinyl adhesive strength was measured. The results are shown in Table 1. Also, 4
Table 1 also shows the 180° vinyl adhesive strength at 0°C.

Comparative Example A butyl rubber adhesive (benzene content: 30% by weight) was applied onto polyethylene tape and polypropylene tape using a roll coater, dried, and the adhesive tape was pressed onto a copper plate to determine its 180' vinyl adhesive strength. was measured. The results are shown in Table 1.

Claims (2)

[Claims] (1) An adhesive for anticorrosion tape comprising a hydroxyl group-containing liquid diene polymer, a polyisocyanate compound, and a bituminous substance. (2) The adhesive according to claim 1, wherein the amount of the polyisocyanate compound is such that the isocyanate group/hydroxyl group (equivalent ratio) is 1.5 to 10.0.