JPH0211680A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain a coating composition improved in abrasion resistance of coating film and adhesion on substrate by mixing a polyurethane obtained from a polyol, triethanolamine and a polyisocyanate with a fluorocarbon resin and a silicone oil in a specified ratio. CONSTITUTION:A polyurethane of a polyol to triethanolamine molar ratio of 1:(0.05-2.0) and a hydroxyl group to isocyanate group molar ratio of 1:(1.5-7) is obtained from a polyol such as polyoxypropylene glycol, triethanolamine and a polyisocyanate such as 2,4-tolylene diisocyanate. 100 pts.wt. this polyurethane is mixed with 2-100 pts.wt. fluorocarbon resin such as polytetrafluoroethylene and 5-200 pts.wt. silicone oil such as dimethylsilicone oil.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a coating composition suitable for coating rubber products, synthetic resin products, etc.

[Prior art] Conventionally, natural rubber (NR), styrene-butadiene copolymer rubber (SBR), butadiene rubber (BR), isobutylene-isoprene copolymer rubber (IIR), chloroprene rubber (CR), acrylonitrile-butadiene copolymer rubber (NBR), isoprene rubber (IR), ethylene-propylene-diene copolymer rubber (EPDM), ethylene-propylene copolymer rubber (EPT), and other synthetic rubbers, cotton, rayon, ABS, PS, etc., are coated with nylon. Resin-based paints such as epoxy-based, acrylic-based, acrylic-ethylene copolymer-based paints, or rubber-based paints such as BR, CR, and SBR are used.

[Problems to be Solved by the Invention] The conventional resin-based paints and rubber-based paints described above have poor adhesion to coated objects such as rubber, synthetic resins, and fibers, and the abrasion resistance of the resulting paint films is poor. There was a problem that it was inferior.

An object of the present invention is to solve the above-mentioned problems and provide a coating composition that provides a coating film with excellent abrasion resistance and good adhesion to the object to be coated.

[Means for Solving the Problems] In order to achieve the above object, the coating composition of the present invention comprises a polyol, triethanolamine and polyisocyanate, and the molar ratio of polyol:triethanolamine is l:o, 05 to 0. 2.0, and the molar ratio of hydroxyl group: isocyanate group is 1 = 1.5 to 7, and fluororesin 2 to 100 parts by weight of the same polyurethane.
100 parts by weight and 5 to 200 parts by weight of silicone oil.

[Detailed Description of Means] First, the polyurethane used in the present invention will be described.

Polyols include polyoxypropylene glycol (PPG), propylene oxide adduct of glycerin, propylene oxide adduct of trimethylolpropane, propylene oxide adduct of pentaerythritol, triethylene glycol (TG), addition of propylene oxide to shio tang. Examples include compounds such as

The polyoxypropylene glycol preferably has a number average molecular weight in the range of 800 to 6,000.

The amine is triethanolamine, and a crosslinking reaction occurs with monoethanolamine and jetanolamine.
It is unsuitable because polyurethane gels.

Polyisocyanate is a compound having a plurality of isocyanate groups, such as 2,4-)lylene diisocyanate (TD I), 65/35 (ratio of 2,4-lylene diisocyanate and 2,6-1-lylene diisocyanate, Same below) Tolylene diisocyanate, 80
/20) lylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), dianisidine diisocyanate, tridene diisocyanate, hexamethylene diisocyanate, metaxylene diisocyanate, l5-naphthalene diisocyanate (NDI)
), hydrogenated 4,4'-diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, hydrogenated 2,4-)lylene diisocyanate, hydrogenated 65/35 tolylene diisocyanate, hydrogenated 80/20 tolylene diisocyanate,
Isophorone diisocyanate) (IPDI), 4.4
', 4''-triphenylmethane triisocyanate, tris(p-isocyanate phenyl) thiophosphate, etc. are used.

The molar ratio of the polyol:triethanolamine is 1:
It is 0.05 to 2.0. If this ratio is less than 0.05 or more than 2.0, the adhesion of the resulting coating film to the object to be coated will be greatly reduced.

Further, the molar ratio of hydroxyl group (-OH) in the polyol to isocyanate group (-NCO) in the polyisocyanate is t:t, S~7, and the isocyanate group is blended in excess with respect to the hydroxyl group.

When this ratio is less than 1.5 or more than 7, the adhesion of the resulting coating film to the object to be coated decreases, and may not adhere properly.

As the fluororesin, polytetrafluoroethylene, polychlorotrifluoroethylene, trifluoroethylene, vinylidene fluoride, etc. are used. The blending ratio of this fluororesin is in the range of 2 to 100 parts by weight per 100 parts by weight of the polyurethane. If the proportion is less than 2 parts by weight, the abrasion resistance will not improve, and if it exceeds 100 parts by weight, it will be difficult to apply the coating composition.

As the silicone oil, dimethyl silicone oil, methyl chloride silicone oil, methyl hydrogen silicone oil, methylphenyl silicone oil, fluorosilicone oil, etc. are used. The blending ratio of this silicone oil is 5 parts by weight based on 100 parts by weight of the polyurethane.
~200 parts by weight. If the blending ratio is less than 5 parts by weight, it is impossible to improve the abrasion resistance, and even if it is blended in an amount exceeding 200 parts by weight, the effect of improving the abrasion resistance does not change, but instead the adhesion deteriorates. .

In the present invention, a solvent is used if necessary. The same solvents include benzene, toluene, xylene, ethylbenzene, trichloroethylene, ethylene chloride, dimethylformamide (DMF), dimethyl sulfoxide, methyl ethyl ketone, atocene, methyl isopropyl ketone, methyl isobutyl ketone, methyl acetate, ethyl acetate, isopropyl acetate. , n-butyl acetate, isobutyl acetate, anisole, tetrahydrofuran, and the like.

The blending ratio of this solvent is 10 parts by weight in 100 parts by weight of the coating composition.
A range of 90 parts by weight is preferred. If the blending ratio is less than 10 parts by weight, the solid content will be relatively high and the viscosity of the coating composition will increase, making coating work difficult and likely resulting in a decrease in adhesion; if it exceeds 90 parts by weight, On the contrary, the proportion of solids becomes low and the film thickness of the coating composition becomes thin, which is not preferable as a coating material.

The coating composition of the present invention is prepared, for example, as follows. First, the polyol, triethanolamine, polyisocyanate, and a necessary solvent are appropriately selected and mixed, and the mixture is reacted at 80° C. for 3 hours in dry nitrogen gas to prepare a polyurethane having isocyanate groups.

Next, 2 to 100 parts by weight of fluorine sealant and 5 to 200 parts by weight of silicone oil are added to 100 parts by weight of this polyurethane.
Parts by weight are added, and a solvent is added to adjust the viscosity for application. In this case, a part of the fluororesin may be replaced with molybdenum disulfide, glass fiber, carbon fiber, polyethylene, silicon oxide, calcium carbonate, magnesium carbonate, clay, or the like.

[Function] By adopting the above means, the coating composition improves the abrasion resistance of the resulting coating film due to the characteristics such as the lubricity of the silicone oil and the low coefficient of friction of the fluororesin, and also improves the abrasion resistance of the resulting coating film. The properties of the polyurethane, which is composed of ethanolamine and polyisocyanate and has a specific structure having isocyanate groups, improve the adhesion to the coated object.

[Examples 1 to 12 and Comparative Examples 1 to 6] Examples embodying the present invention will be described below in comparison with comparative examples.

First, the object to be coated is the following vulcanizate.

That is, the vulcanizate contained 100 parts by weight of EPDM (hereinafter simply referred to as "parts"), 70 parts of carbon blank, 35 parts of mineral oil, 7 parts of zinc oxide, 2 parts of stearic acid, 2 parts of vulcanization accelerator, and 1 part of sulfur.
．． A composition consisting of 5 parts was vulcanized at 160°C for 30 minutes.

In addition, the wear resistance test was conducted by the following method, and the wear resistance was evaluated based on the amount of wear loss.

That is, Test machine: Tipper type rotary abrasor (manufactured by Toyo Seiki Seisakusho Co., Ltd.) Test conditions: Wear wheel, H-22, load 11 kg Wear rotation speed: 60 rpm Sample size i 100 mm x 100 mm Number of wear, 1000 times Next, the following table - Polyol (PO), triethanolamine (TEA), polyisocyanate (PI) shown in 1
were mixed in trichlorethylene and reacted at 80° C. for 3 hours in a nitrogen gas atmosphere to synthesize polyurethane. The obtained polyurethane had a solid content of 83% and a trichlorethylene content of 17%.

Table-1 The abbreviations in Table-1 represent the following meanings.

PPG 3000: Polyoxypropylene glycol with a number average molecular weight of 3000 PPG 1000: Polyoxypropylene glycol with a number average molecular weight of 11000 PPG 2000: Polyoxypropylene glycol with a number average molecular weight of 2000 TG 3000: Triethylene glycol TG 1000 with a number average molecular weight of 113000: Triethylene glycol with a number average molecular weight of 1000 TG 2000: Triethylene glycol with a number average molecular weight of 2000 MDI: 4,4'-diphenylmethane diisocyanate ND (: 1.5-naphthalene diisocyanate XDI:
Xylylene diisocyanate IPDI: Isophorone diisocyanate Next, predetermined amounts of fluororesin and silicone oil shown in Table 2 below were blended with 100 parts by weight of the solid content of the polyurethane to obtain a coating composition.

This coating composition was applied to the object to be coated, dried at 80° C. for 20 minutes, and then subjected to the abrasion resistance test. The results are also shown in Table-2.

back The abbreviations in Table-2 represent the following meanings.

#: Polytetrafluoroethylene DMSi Nidimethyl silicone oil - Viscosity 10,000 centistokes (cSt) *: Degree 60,000 C3t *: Viscosity 100,000 cSt Further, the amount of wear is expressed in mg/1000 times.

In addition, as a comparative example, a coating composition as shown in Table 3 was prepared, applied to the object to be coated in the same manner, dried, and then subjected to an abrasion resistance test.The results are also shown in Table 3 above. The meanings of the abbreviations are as follows.

#: Same as the above--2 fluororesin.

; Same as the silicone oil in Table 2 above.

*: Same as the above-2 silicone oil.

*: Same as silicone oil in Table 2 above.

As can be seen from Table 2 above, the paint compositions of each example showed abrasion loss of 3.3% even after 1000 abrasion tests.
The amount is extremely small, ranging from 1 to 5.8 mg.

The reason why the coating compositions of each example exhibit such excellent wear resistance without impairing the material properties of the object to be coated is due to the lubricity of silicone oil and the low friction coefficient of fluororesin. It is presumed that this is based on the following.

Further, the coating composition of each example contained a predetermined amount of polyol,
It is composed of triethanolamine and polyisocyanate, and exhibits excellent adhesion to the vulcanized rubber to be coated due to the properties of polyurethane containing isocyanate groups.

On the other hand, as can be seen from Table 3, the paint compositions of each comparative example had a large abrasion loss of 251.7 to 3951.6 mg.
Poor wear resistance.

[Effects of the Invention] The coating composition of the present invention has excellent effects in that the resulting coating film has good abrasion resistance and good adhesion to the object to be coated.

Claims (1)

[Claims] 1. Consisting of polyol, triethanolamine and polyisocyanate, with a polyol:triethanolamine molar ratio of 1:0.05 to 2.0, and a hydroxyl group:
A polyurethane having a molar ratio of isocyanate groups of 1:1.5 to 7, 2 to 100 parts by weight of a fluororesin to 100 parts by weight of the polyurethane, and 5 to 200 parts by weight of a silicone oil.
A coating composition consisting of parts by weight.