JPS608028B2 - paint composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating composition based on a urethane polymer.

More particularly, the present invention relates to coating compositions suitable for application to ethylene-propylene vulcanizates and olefinic thermoplastic rubbers. Ethylene-propylene vulcanized rubber and olefin thermoplastic rubber are natural rubber (N
R), styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR), isobutylene-isopropylene copolymer rubber (11R), polychloroprene rubber (C
R), acrylonitrile-butadiene copolymer rubber (NB
Compared to synthetic rubbers such as R) and polysoprene rubber (IR), it exhibits superior performance in terms of weather resistance, aging resistance, ozone resistance, etc., and also has a wide operating temperature range of -50°C to 15,000°C. It is a rubber material with excellent characteristics such as, and is now used in many fields.

However, since these rubber materials do not contain unsaturated bonds or polar groups in their main chains, even if a paint is applied, the resulting coating film is likely to peel off, making it extremely difficult to paint these rubber materials.

A number of countermeasures have already been attempted to address these drawbacks.

For example, '1' Polish the surface with a wire brush, sandpaper, etc. [2] Irradiate with ultraviolet rays [3- Soak in concentrated sulfuric acid, ■ Treat with a mixed solution of organic monocarboxylic acid and phosphoric acid, {5' Aldehyde '6' Painting a mixture of chlorinated polypropylene and ethylenediamine, '7} Treating with chlorinated isocyanates, [
These methods include oxidizing the surface by exposing it to 8 liters of ozone, treating it with a side alkyl hypohalite, and treating it with an epoxy resin modified with a monopolymerized fatty acid, an amine curing agent, and an organic solvent. However, in these conventional processing methods, ■ there is a tendency for uneven polishing to occur, ■ there are hygiene problems due to the generation of dust, ■ it causes deterioration of the vulcanizate, ■ there is danger in handling the processing agent, and ■ There are disadvantages such as requiring a special treatment agent, ■The treatment process is complicated, and ■The equipment is expensive, and even if such treatment is applied, the adhesion of the paint is not necessarily sufficient. I couldn't say that it was. The present inventors have been researching paints for the above-mentioned rubber materials, and found that they have developed a paint composition that has sufficient adhesion to the surface of the rubber materials without impairing the flexibility and flexibility that are the characteristics of these rubber materials. Look at it, take it out,
The present invention has now been completed.

That is, the present invention provides polyhydroxypolybutadiene (a) which has been hydrogenated by 98% or more, and one or more types of polyether or polyester diols (b-) and a diisocyanate {c}. The present invention provides a coating composition characterized in that the main component is a urethane polymer having terminal isocyanate groups or hydroxyl groups obtained by reacting a urethane prepolymer having isocyanate groups with a low-molecular-weight diol.

To explain the present invention in detail below, firstly, ``the 98% or more hydrogenated polyhydroxypolybutadiene used in the coating composition of the present invention means at least one polyhydroxypolybutadiene per molecule, preferably from 1.8 to 1. It is a polybutadiene polymer with 5.0 hydroxyl groups, and the average molecular weight is usually 500-5.
0,000, preferably 1,000 to 20,000, and various known methods can be adopted as the manufacturing method, although it is not specified. For example, in the polymerization of butadiene, hydrogen peroxide, cyclohexanone peroxide, methyl ethyl ketone peroxide, azobis-based compounds having functional groups, such as 8'-azobis(muciano)-n-
Propanol, 6,6-azobis(6-cyano)-n-
Radical polymerization may be carried out in a catalyst such as alcohol, ketone, or ester using a radical polymerization initiator containing a hydroxyl group such as pentanol, or radical polymerization may be carried out using a radical polymerization initiator such as aliphatic azodicarboxylic acid or its ester. There is also a method in which polyhydroxyptadiene is obtained by similarly polymerizing and then reducing the carboxyl group or ester moiety.

Alternatively, anionic polymerization may be performed using an alkali metal such as sodium or lithium or a polymer of an alkali metal and a polycyclic aromatic compound as a catalyst, followed by functionalization with alkylene oxide, epichlorohydrin, or the like.

Specifically, the catalyst used for anionic polymerization is a lithium body such as naphthalene rust, anthracene complex, biphenyl rust, 1,4-dialkali metal butane, 1,5-dialkali metal pentane, 1,10-dialkali metal, etc. Metal decane, 1,4-dialkali metal, 1,1,
Mention may be made of dialkali metal hydrocarbons such as 4,4-tetraphenylbutane. Furthermore, in order to smoothly proceed with such anionic polymerization, hexane, heptane, benzene,
Hydrocarbon solvents such as toluene, xylene, and cyclohexane are used.

However, when an alkali metal is used as a catalyst, it is preferable to use the above solvent together with a Lewis base such as diethyl ether, dipropyl ether, ethyl propyl ether, or ethyl butyl ether. Polyhydroxybutadiene can be obtained by reacting the Bing polymer thus obtained with an epoxy compound according to a conventional method, and then treating it with a protic acid such as hydrochloric acid, sulfuric acid, or acetic acid.

Epoxy compounds used here include ethylene oxide, propylene oxide, butylene oxide,
Monoepoxy compounds such as cyclohexene oxide, styrene oxide, phenylglycidyl ether: glycidyl ether of bisphenol A, vinylcyclohexene diepoxide, butadiene diepoxide, dicyclobentadiene diepoxide, limonene diepoxide, bisepoxide of ethylene glycol Polyepoxy compounds such as: haloepoxy compounds such as epichlorohydrin, epibromohydrin, and methylepichlorohydrin can be used.

More preferred are polyepoxy compounds and haloepoxy compounds. In the case of a monoepoxy compound, the amount used is preferably an equimolar ratio, particularly 2 or more molar ratio, to the polymer.

At this time, it is considered that the epoxy compound is bonded to both ends of the living polymer in a ring-opened manner, and the hydrogen atoms of the ring-opened hydroxy groups are bonded to each other while being substituted with an alkali metal. On the other hand, when using a polyepoxy compound or a haloepoxy compound, it is selected appropriately depending on the use of the obtained polymer, that is, the molecular weight and number of hydroxyl groups of the polymer, but usually 0.5 to
A molar ratio of 2.0, preferably 0.6 to 1.0 is used.

At this time, after the epoxy is ring-opened, living polymers are mainly bonded to each other to obtain a polymer in which several molecules are bonded via an epoxy compound having a hydroxyl group substituted with an alkali metal.

Polyhydroxy and polybutadiene can also be obtained by reducing a high molecular weight polybutadiene polymer by ozonolysis or other methods, and reducing an oxygen-containing polymer. Regarding the microstructure of the obtained polyhydroxypolybutadiene, polymers having various ratios of 1.2-bonds and 1.4-bonds can be obtained depending on the manufacturing method. For example, the microstructure of polyhydroxypolybutadiene produced using a radical polymerization method has 5 to 30% cis-1,4 bonds and 5 trans-1,4 bonds.
0 to 80%, 1.2 bonds account for 15 to 30%, and usually 1
・It has a microstructure with many 4 bonds. Further, in the anionic polymerization method, polyhydroxypolybutadiene having many 1,4-bonds can be obtained by selecting the type of catalyst and solvent used. The hydrogenated polyhydroxypolybutadiene used in the composition of the present invention is obtained by hydrogenating the double bonds in the main chain and/or side chains of the polyhydroxypolybutadiene produced in this manner while retaining the hydroxyl groups. obtained by doing. As the hydrogenation catalyst, nickel, cobalt, chromium, copper, palladium, platinum, rhodium, osmium, ruthenium, rhenium, etc. are generally used, with nickel and ruthenium being preferred. These various metal catalysts are used as the metal itself, as a heterogeneous catalyst supported on a carrier, or as a homogeneous catalyst in which the metal is a soluble salt. The above carriers include carbon, alumina,
Silica, alumina/silica, diatomite, barium carbonate, calcium carbonate, etc. are used.

The amount of the metal supported on this tin-coated carrier is usually 0.01 to 5.
% by weight, preferably from 0.2 to 15% by weight. Although polyhydroxypolybutadiene can be reacted as it is with hydrogen using the above-mentioned metal as a catalyst, a better hydrogenation reaction can be carried out by using a solvent. As this solvent, aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, alcohols, or mixed solvents thereof can be used. The amount of the above-mentioned catalyst used in hydrogenation varies depending on the type of tactile plant, hydrogenation method, etc., but for example, when carrying out suspension polymerization using a ruthenium catalyst, the ratio of ruthenium to polyhydroxypolybutadiene is is used in a range of 0.01 to 1.0% by weight.

The reaction temperature is preferably 20 to 150°C. If the reaction temperature becomes high, the hydrogenation rate can be increased, but this is not preferable because the cleavage of hydroxyl groups becomes non-negligible.
The hydrogen used may be used at normal pressure, in a flow system or at high pressure, and the hydrogenation reaction may be carried out in any reaction form such as a fixed bed suspension system. Under the above-mentioned hydrogenation conditions, the double bonds in the main chain and/or side chain in polyhydroxyvriptadiene are hydrogenated. It is necessary that the bonds are almost completely hydrogenated, with 98% of the double bonds in the polymer before hydrogenation.
It is necessary to hydrogenate the hydrogenation to preferably 99% or more, more preferably until substantially no double bonds remain.

The polyether-based or polyester-based diol in the composition of the present invention includes polypropylene oxide glycol, polytetramethylene oxide glycol, polyethylene-butylene adipate, polyethylene adipate,
It is a diol exemplified by polybutylene adipate, polyethylene adipate, etc., and diisocyanate is
The diisocyanate is exemplified by toluene diisocyanate, 4,4'-phenyl diisocyanate, 4,4-phenylmethane diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, xylene diisocyanate, and the like.

Moreover, low molecular diols are diols exemplified by ethylene glycol, propylene glycol, butylene glycol, bentanediol, hexanediol, octanediol, diethylene glycol, triethylene glycol, neobentyl glycol, dipropylene glycol, and the like. The coating composition of the present invention comprises polyhydroxypolybutadiene 'a} as described above, polyether-based or polyester-based diol [b}, and diisocyanate [C
1 as a raw material, for example in dry nitrogen gas, 80
℃ for 3 hours to produce a urethane prepolymer having an isocyanate group at the end. Further, an organic solvent, for example, is added to this urethane prepolymer, a low molecular weight diol is added thereto, and the mixture is reacted in, for example, dry nitrogen gas. , 80
oo, a urethane polymer having an isocyanate group or a hydroxyl group at the end is synthesized by carrying out a chain extension reaction for 2 minutes, and the urethane polymer thus obtained is the main component.

Therefore, the composition of the present invention is used by adding conventional additives such as pigments, dyes, anti-aging agents, inorganic fillers, etc. to the urethane polymer. The coating composition of the present invention has very good adhesion to ethylene-propylene vulcanized rubber and olefin thermoplastic rubber. In addition, since this paint composition is a one-component urethane, dry nitrogen gas,
Long-term storage is possible if stored in dry air at 20 qo or less. The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

The ethylene-propylene rubber vulcanizate used in the examples was prepared as follows.

A rubber compound containing 10 parts of ethylene-propylene turbo polymer, 5 parts of carbon black, 3 parts of mineral oil, 5 parts of zinc white, 1 part of stearic acid, 2 parts of vulcanization accelerator, and 1.5 parts of sulfur was added to 16,000 parts. The ethylene-propylene-turbulima vulcanizate was obtained by carrying out zero sulfurization on three ships for the first time.

Example 1 20 parts of polyhydroxybutadiene (molecular weight approximately 2000) with double bonds hydrogenated to 98% or more, polypropylene oxide glycol (molecular weight approximately 2000)
574 parts, polyethylene adibate (molecular weight approximately 2000
), 56 parts of 4,4-diphenylmethane diisocyanate, and 168 parts of trichlorethylene were mixed in dry nitrogen at 80°C for 3 hours to synthesize a urethane prepolymer.

In addition to this urethane prepolymer, 1 as a chain extender is added.
14 parts of 16-hexanediol and 1,322 parts of dimethylformamide were added and reacted at 80°C for 20 minutes in dry nitrogen to obtain a urethane polymer solution. A coating composition was prepared by adding 1 part of carbon black to 100 parts of this urethane polymer solution. This coating composition was applied to the rubber calosulfate prepared as described above and cured at 100°C for 18 minutes.

As a result of the Goban eye peeling test with Sellotape,
No separation was allowed. Example 2 Polyhydroxybutadiene (molecular weight approximately 2000) as in Example 1 10 parts, polypropylene oxide glycol (molecular weight approximately 1000) 48 parts, polypropylene oxide glycol (molecular weight approximately 2000) 540 parts, 4.4 parts
- Urethane prepolymer obtained by reacting 80 parts of diphenylmethane diisocyanate and 192 parts of trichlorethylene in the same manner as in Example 1, 10 parts of 1,6-hexanediol, and 110 parts of dimethylformamide. was added, and the reaction was carried out in the same manner as in Example 1 to obtain a urethane polymer solution.

10 parts of this polymer solution and 15 parts of carbon black were added to obtain a coating composition. This coating composition was applied to the rubber vulcanizate prepared as described above, and the procedure was repeated in the same manner as in Example 1. A chick test was conducted using cellophane tape, and no chicks were observed.

Example 3 The same polyhydroxybutadiene as in Example 1 (molecular weight approximately 2000) 40 anchor parts, polytetramethylene oxide glycol (molecular weight approximately 2000) 572 parts, polypropylene oxide glycol (molecular weight approximately 2000) 116 base parts,
130 parts of 4,4-diphenylmethane diisocyanate and 343 parts of trichlorethylene were reacted in the same manner as in Example 1 to obtain a urethane prepolymer solution.

This urethane prepolymer was made into a urethane polymer solution in the same manner as in Example 1, and 10 parts of this polymer solution and 20 parts of Bokaku Moko carbon black were added to prepare a coating composition. This composition was applied to the rubber vulcanizate prepared as described above, and a peeling test was performed using Sellotape in the same manner as in Example 1. As a result, no peeling chicks were observed.

The coating composition of the present invention exhibits surprising adhesion when used as a coating material for ethylene-propylene vulcanized rubber or olefin thermoplastic rubber, and can be used as a coating composition for these rubber materials, which were conventionally difficult to coat. , showing ground-breaking applicability.

Claims (1)

[Claims] 1 98% or more hydrogenated polyhydroxypolybutadiene (a), one or more polyether or polyester diols (b), and diisocyanate (
The main component is a urethane polymer having an isocyanate group or a hydroxyl group at the end obtained by reacting a urethane prepolymer having an isocyanate group at the end obtained by reacting with c) with a low molecular diol. Paint composition.