JPH0676577B2 - Adhesive for ethylene-propylene-diene rubber - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an adhesive for ethylene-propylene-diene rubber adhesive (EPDM), and more specifically to an adhesive strength, particularly 180
The present invention relates to an EPDM adhesive having improved peel strength.

[Problems to be Solved by Prior Art and Invention]

Conventionally, various excellent adhesives have been known as adhesives for natural rubber and synthetic rubber, but no good adhesive has been found among the adhesives using EPDM as an adherend. is the current situation.

Under such circumstances, a prepolymer obtained by reacting a hydroxyl group-containing liquid diene polymer with a polyisocyanate compound is known as a relatively good adhesive for EPDM.

However, this adhesive is not yet satisfactory in 180 ° peel strength, and its improvement is desired.

The present inventors have conducted intensive studies to solve the above-mentioned drawbacks of the conventional adhesives and develop an adhesive for EPDM having a remarkably improved 180 ° peel strength.

[Means for solving problems]

As a result, they have found that the object can be achieved by using a hydroxyl group-containing liquid diene polymer, a polyisocyanate compound and a specific polyol, and mixing and reacting the polyisocyanate compound in an excessive ratio.

The present invention has been completed based on such findings. That is, the present invention provides a prepolymer obtained by mixing a hydroxyl group-containing liquid diene polymer, a liquid poly (oxytetramethylene) glycol and a polyisocyanate compound at a ratio of isocyanate group / hydroxyl group (molar ratio) of 1.5 or more and reacting them. An adhesive for EPDM containing a polymer as a main component is provided.

The hydroxyl group-containing liquid diene polymer used in the present invention is a liquid diene polymer having a molecular chain, preferably a hydroxyl group at the terminal of the molecular chain, and a number average molecular weight of 300 to 25,000, preferably 500 to 10,000. These liquid diene-based polymers are C4-12 diene polymers, diene copolymers, and copolymers of these diene monomers and C2-22 α-olefin addition polymerizable monomers. and so on. The hydroxyl group content is 0.1 to 10 meq / g, preferably 0.3 to 5.0 meq / g. Specific examples thereof include butadiene homopolymer, isoprene homopolymer, butadiene-styrene copolymer, butadiene-isoprene copolymer, butadiene-acrylonitrile copolymer, butadiene-2-ethylhexyl acrylate copolymer, butadiene-n-octadecyl acrylate copolymer and the like.
These liquid diene polymers can be produced, for example, by reacting a conjugated diene monomer in a liquid reaction medium in the presence of hydrogen peroxide with heating.

Then, liquid poly (oxytetramethylene) glycol (PTMG) is usually one represented by _{HOCH 2 -CH 2 -CH 2 -CH 2} -O n H, wherein n is 5 to 50 integer, Preferably, it represents an integer of 10 to 45. This PTMG can be produced by ring-opening polymerization of tetrahydrofuran with a strong acid catalyst. It can also be produced using dichlorobutene and 1,4-butanediol as raw materials.

On the other hand, the polyisocyanate compound is an organic compound containing two or more isocyanate groups in one molecule, and the hydroxyl group-containing liquid diene polymer and the active hydrogen-containing functional group of liquid poly (oxytetramethylene) glycol. It has a reactive isocyanate group for the group. Examples of the polyisocyanate compound include ordinary aromatic, aliphatic and alicyclic compounds,
For example, tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate (MDI), liquid modified diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, xylylene diisocyanate, cyclohexyl diisocyanate, cyclohexanephenylene diisocyanate, naphthalene-1,5-diisocyanate, isopropylbenzene-2, 4-diisocyanate, polypropylene glycol and tolylene diisocyanate addition reaction products,
Especially MDI, liquid diphenylmethane diisocyanate,
Tolylene diisocyanate and the like are preferable.

In the present invention, the above-mentioned hydroxyl group-containing liquid diene polymer, PT
The mixing ratio of MG and the polyisocyanate compound is such that the polyisocyanate compound is in an excessive amount, that is, the isocyanate group (NC) in the polyisocyanate compound relative to the total amount of the hydroxyl group-containing liquid diene polymer and the hydroxyl group (OH) in PTMG.
O) ratio NCO / OH (molar ratio) is 1.5 or more, preferably 1.7 to 2
It is 5 (molar ratio), most preferably 2 to 15 (molar ratio). If the NCO / OH (molar ratio) is less than 1.5, the resulting prepolymer cures instantly, which makes it unsuitable for use as an adhesive. The mixing ratio of the hydroxyl group-containing liquid diene polymer and PTMG is not particularly limited,
Usually, PTMG is 5 to 100 parts by weight, preferably 10 to 90 parts by weight, based on 100 parts by weight of the hydroxyl group-containing liquid diene polymer.

In the present invention, these components may be mixed and reacted in an appropriate order to obtain a prepolymer. The production procedure will be described in detail. (I) Hydroxyl group-containing liquid diene polymer and PT
To obtain a prepolymer by reacting an excess amount of polyisocyanate compound with a mixture with MG, (II) reacting an excess amount of polyisocyanate compound with a hydroxyl group-containing liquid diene polymer into a prepolymer, which is reacted with PTMG To obtain a desired prepolymer, or (III) PTMG is reacted with an excess amount of a polyisocyanate compound to form a prepolymer, and a hydroxyl group-containing liquid diene polymer is reacted therewith to obtain a desired prepolymer. Can raise the procedure. The excess polyisocyanate compound here is, as described above, the liquid diene polymer and PTMG containing NCO groups and hydroxyl groups in the polyisocyanate compound.
It means the amount in which the molar ratio of the total OH groups (NCO / OH) is 1.5 or more. Further, in the process of producing this prepolymer, various kinds of additive components can be added if necessary. For example, inorganic fillers such as silica, mica, talc, clay, graphite, carbon black, pebble, calcium carbonate, slate powder, feldspar, silicic acid, and white luster can be added.

In addition, a plasticizer such as dioctyl phthalate may be added as a viscosity modifier, or a softener such as aroma, naphthene, or paraffin oil may be added. In addition, alkylphenol resin, terpene resin, Tackifying resins such as terpene phenolic resins, xylene formaldehyde resins, rosins, hydrogenated rosins, coumarone resins, aliphatic and aromatic petroleum resins can also be added. Further, a curing accelerator such as dibutyltin dilaurate, stannous octoate, or polyethylenediamine may be added. Furthermore, a silicon compound or the like can be added as a defoaming agent. In order to improve weather resistance, for example, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole; 2-5-di-tert-aluminohydroquinone; distearylthiopropio Antiaging agents such as nates can also be added.

Since the raw material components as described above are used and the polyisocyanate compound is used in an excessive amount, the product mainly contains a polypolymer having an isocyanate group (NCO) at the terminal or a polyisocyanate compound which has not reacted with this prepolymer. It has become.

The prepolymer constituting the adhesive for EPDM of the present invention thus obtained has a number average molecular weight of 2000 to 9000, preferably 4000 to 8000. Further, the adhesive of the present invention has a moisture curability.

The adhesive of the present invention is very suitably used for adhesion of EPDM, wherein EPDM is ethylene and propylene with a small amount of a diene, such as hexadiene, dicyclopentadiene, ethylidene norbornene, etc., placed in a hydrocarbon solvent, and Ziegler It is obtained by polymerizing with a catalyst or the like.

The adherends to which the adhesive of the present invention is applied are both EP
Of course, in the case of DM, if at least one is EPDM, the other is rubber other than EPDM, various synthetic resins (polyvinyl chloride, polypropylene, polystyrene, polycarbonate, polybutylene terephthalate, etc.), paper, wood,
There are various materials such as cloth, metal, mortar and concrete.

To perform the bonding using the adhesive for EPDM of the present invention, the adhesive is applied to one or both surfaces of the adherend as described above by a means such as coating or spraying, and then the adherends are adhered to each other. May be laminated and an appropriate curing treatment may be performed.

〔Example〕

 Next, the present invention will be described in more detail with reference to examples.

Production Example 1 Liquid hydroxyl-containing liquid polybutadiene (number average molecular weight 280
0, hydroxyl content 0.79 meq / g, trade name: R45HT, 100 parts by weight of Idemitsu Oko Co., Ltd. and 85 parts by weight of liquid poly (oxytetramethylene) glycol (number average molecular weight 2000, DuPont Japan) Put in a container, at 25 ℃
Stir for 30 minutes, then heat the mixture at 80 ° C. for 3 hours. Thereafter, 110 parts by weight of diphenylmethane diisocyanate as a polyisocyanate compound was added to this mixture to set the NCO group / OH group (molar ratio) of the reaction system to 11,
The reaction was carried out at 25 ° C for 3 hours.

As a result, a prepolymer having a viscosity of 500 poise / 25 ° C. and a free NCO group of 5.4% by weight was obtained.

Production Example 2 100 parts by weight of liquid polybutadiene having terminal hydroxyl groups (the same as in Production Example 1) was heated at 80 ° C. for 3 hours, and 85 parts by weight of diphenylmethane diisocyanate (the same as in Production Example 1) was added as a polyisocyanate compound. And 25 ℃
Was reacted for 1.5 hours. Then, liquid poly (oxytetramethylene) glycol (the same as in Production Example 1) 110
By adding 1 part by weight, the mixture was reacted at 25 ° C for 1.5 hours to obtain a propolymer having a viscosity of 450 poise / 25 ° C and a free NCO group of 5.4% by weight.

Production Example 3 100 parts by weight of liquid polybutadiene containing terminal hydroxyl groups (the same as in Production Example 1) was heated at 80 ° C. for 3 hours, and 30 parts by weight of diphenylmethane diisocyanate (the same as in Production Example 1) was added as a polyisocyanate compound. And 25 ℃
React for 1.5 hours at a viscosity of 300 poise / 25 ℃, free NCO
A prepolymer of 5.0% by weight of base was obtained.

Examples 1 and 2 and Comparative Example Each of the prepolymers obtained in Production Example was treated with EPDM (trade name: JSR
EP, manufactured by Japan Synthetic Rubber Co., Ltd.) to a thickness of 0.5 mm, and then laminated with cotton canvas, and then at room temperature (around 25 ° C) for 1
Moisture hardening treatment is performed for 1 week in accordance with JIS K 6854.
The 80 ° peel strength was measured.

The results are shown in the table.

[Advantages of the Invention] When the adhesive of the present invention is applied when EPDM is used as an adherend, the adhesive strength (180
Peel strength) can be increased.

Therefore, the adhesive of the present invention is effectively used as an excellent adhesive in various fields using EPDM.

Claims (2)

[Claims] 1. A hydroxyl group-containing liquid diene polymer, a liquid poly (oxytetramethylene) glycol and a polyisocyanate compound are used as isocyanate groups / hydroxy groups (molar ratio).
Is an adhesive for ethylene-propylene-diene rubber, which is mainly composed of a prepolymer obtained by mixing and reacting at a ratio of 1.5 or more. 2. A liquid poly (oxytetramethylene) glycol having a general formula of HOCH ₂ —CH ₂ —CH ₂ —CH ₂ —O _n H [wherein n represents an integer of 5 to 50]. ] The adhesive agent of Claim 1 represented by these.