JPH02158673A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain a coating composition composed of a specific polyurethane, a fluororesin and silicone diamine in a specific proportion which is suitable for coating rubber products and synthetic resin products, because it has excellent abrasion properties on the coating surface and high adhesion between the coating film and the substrate. CONSTITUTION:The objective composition is composed of (A) 100 pts.wt. of polyurethane in which polyol, triethanolamine, and polyisocyanate wherein the molar ratio of the polyol to the triethanolamine is 1:(0.05 to 2.0) and the molar ratio of OH:NCO is 1:(1.5 to 7), (B) 2 to 100 pts.wt. of a fluororesin, (C) a silicone diamine at a molar ratio of (0.7 to 1.3):1 NH2 to NCO.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a coating composition for coating rubber products, synthetic resin products, etc.

[Conventional technology] Conventionally, natural rubber (NH), styrene-butadiene copolymer rubber (SBR), butadiene rubber (BR), isobutylene-isoprene copolymer rubber (IIR), chloroprene rubber (CR), acrylonitrile-butadiene copolymer rubber (NBR), isoprene For surface coating of synthetic rubber such as rubber (IR), ethylene-propylene-diene copolymer rubber (EPDM), ethylene-propylene copolymer rubber (EPM), cotton, rayon, ABS, PS''!, nylon-based, epoxy Resin-based paints such as acrylic, acrylic, and acrylic-ethylene copolymer, or rubber-based paints such as BR, CR, and SBR are used. [Problem to be solved by the invention] The above-mentioned conventional resin-based paints and rubber-based paints have problems in that they have poor adhesion to coated objects such as rubber, synthetic resins, fibers, etc., and the resulting paint films have poor abrasion resistance. An object of the present invention is to provide a coating composition that provides a coating film with excellent abrasion resistance and good adhesion to the object to be coated. [Means to solve the problem]

In order to achieve the above object, the coating composition of the present invention comprises a polyol, triethanolamine and polyisocyanate, the molar ratio of polyol:triethanolamine is 1:0.05-2.0, and the hydroxyl group (- OH)
: The molar ratio of isocyanate groups (-NCO) is 11.5 to
7, 2 to 100 parts by weight of fluororesin per 100 parts by weight of the same polyurethane, and silicone diamine with amino groups (-NH2) and isocyanate groups (-N
CO) in an amount such that the molar ratio is from 0.7 to t3xi. [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 sucrose. Examples include compounds such as The above polyoxypropylene glycol has a number average molecular weight of 8
A value in the range of 00 to 6000 is preferred. 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 incyanate groups, such as 2,4-)lylene diisocyanate (TDI), 65/35 (ratio of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, the same applies hereinafter) ) Tolylene diisocyanate, 80/20
) lylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), dianisidine diisocyanate, tridene diisocyanate, hexamethylene diisocyanate, mexylene diisocyanate,
1,5-naphthalene diisocyanate (NDI), water i4,4'-diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, hydrogenated 2,4-1-lylene diisocyanate, hydrogenated 65/35 tolylene diisocyanate, hydrogenated 80/20 tri 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:
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 groups in the polyol and triethanolamine to isocyanate groups in the polyisocyanate is ZtS~7, and the isocyanate groups are blended in excess with respect to the hydroxyl groups. 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 diamine, for example, those having the following structures can be used. In the above formula, n represents an integer of 1 to 20. This silicone diamine has a function as a curing agent for the polyurethane, and the molar ratio of amino groups in the silicone diamine to isocyanate groups in the polyurethane is 0.7.
-1.31. When this molar ratio is less than 0.7 or more than 1.3, the adhesion of the resulting coating film to the object to be coated decreases. 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, to 100 parts by weight of this polyurethane, 2 to 100 parts by weight of fluororesin and silicone diamine were added in an amount such that the molar ratio of amino group/isocyanate group was 0.7 to 1.3, and a solvent was further added for coating. Adjust to the desired viscosity. In this case, part of the fluororesin is molybdenum disulfide,
Glass fiber, carbon fiber, polyethylene, silicon oxide,
It can also be replaced with calcium carbonate, magnesium carbonate, clay, etc. [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. It is presumed that the adhesion to the object to be coated is improved due to the properties of the polyurethane having a specific structure, which is composed of ethanolamine and polyisocyanate and has an incyanate group or an amino group that is cured with silicone diamine. [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 a vulcanized product as shown below. That is, the vulcanizate contains parts by weight of EPDMiOO (hereinafter simply referred to as parts), 70 parts of carbon black, 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: Taper type rotary abrader (manufactured by Toyo Seiki Seisakusho Co., Ltd.) Test conditions: Wear wheel: H-22, load: 1 kg, abrasion rotation speed: 60 rpm, sample size: loomm x 100 + nm, number of abrasions: 10.00 times. Polyol (PO), triethanolamine (TEA), polyisocyanate (PI) shown in Table 1 below
) 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 Table 2 PPG 2000: Polyoxypropylene glycol with a number average molecular weight of 2000 TG 3000: Triethylene glycol with a number average molecular weight of 3000 TG 1000: Triethylene glycol with a number average molecular weight of 1000 TG 2000 F Triethylene glycol with a number average molecular weight of 2000 MDI: 4.4'-diphenylmethane diisocyanate NDIl, 5-naphthalene diisocyanate XDI: Xylylene diisocyanate IPDI: Isophorone diisocyanate Next, the above A coating composition was obtained by blending predetermined amounts of fluororesin and silicone diamine shown in Table 2 below with respect to 100 parts by weight of solid content of polyurethane. 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. The abbreviations in Table-2 represent the following meanings. #: Polytetrafluoroethylene *: Represents the type of silicone diamine and the molar ratio of amino groups in the silicone diamine/isocyanate groups in the polyurethane. (a): n in the general formula of the silicone diamine is 2,
Silicone diamine +b+ having an amine equivalent of 500 and an average molecular weight of 1000; n in the general formula of the silicone diamine is 2, a silicone diamine having an amine equivalent of 1850 and an average molecular weight of 3700 (cl: n in the general formula of the silicone diamine is 2, amine silicone diamine having an equivalent weight of 2200 and an average molecular weight of 4400 (d+: n in the general formula of the silicone diamine is 3; silicone diamine (e) having an amine equivalent of 520 and an average molecular weight of 1040; n in the general formula of the silicone diamine is 3;
Silicone diamine (f) having an amine equivalent of 1760 and an average molecular weight of 3520: n in the general formula of the silicone diamine is 3,
Silicone diamine with an amine equivalent of 2150 and an average molecular weight of 4300 (GL: n in the general formula of the silicone diamine is 4, silicone diamine with an amine equivalent of 950 and an average molecular weight of 1900 (HL: n in the general formula of the silicone diamine is 4, Silicone diamine (1) having an amine equivalent of 1020 and an average molecular weight of 2040: n in the general formula of the silicone diamine is 4,
Silicone diamine with an amine equivalent of 2100 and an average molecular weight of 4200 (jl: n in the general formula of the silicone diamine is IO, and an amine equivalent of 630 and a silicone diamine with an average molecular weight of 1260 (kl: n in the general formula of the silicone diamine is 10°) Silicone diamine (1) having an amine equivalent of 810 and an average molecular weight of 1620; n in the general formula of the silicone diamine is 10
, a silicone diamine with an amine equivalent of 1210 and an average molecular weight of 2420.The wear amount is expressed in mg/1000 times. Next, as a comparative example, a coating composition as shown in Table 3 was prepared, and applied to the object to be coated in the same manner as in Example 1-12 above.
After drying, an abrasion test was conducted. The results are also shown in Table 3. The meanings of the abbreviations in Table 3 above are the same as those in Table 2 above. As can be seen from Table 2 above, the paint compositions of each example had abrasion loss of 8.0% even after 1000 abrasion tests.
The amount is extremely small, ranging from 4 to 11.3 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 presumed to be based on the characteristics of the fluororesin having a small coefficient of friction. 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 having isocyanate groups or amino groups cured with silicone diamine. On the other hand, as can be seen from Table 3, the paint compositions of each comparative example had a large abrasion loss of 943.9 to 3951.6 mg.
Poor wear resistance. As mentioned above, since the coating composition of the present invention has excellent abrasion resistance and adhesion, it is suitably used for automobile weather strips, glass runs, adhesive tapes, and the like. [Effects of the Invention] The coating composition of the present invention has the following effects: the resulting coating film surface has very good abrasion resistance, and the adhesion between the coating film and the object to be coated is excellent.

Claims (1)

[Claims] 1. Consisting of polyol, triethanolamine and polyisocyanate, the molar ratio of polyol:triethanolamine is 1:0.05-2.0, and the hydroxyl group (
-OH): molar ratio of isocyanate group (-NCO) is 1
:1.5 to 7 polyurethane and the same polyurethane 1
A paint comprising 2 to 100 parts by weight of a fluororesin per 00 parts by weight, and silicone diamine in an amount such that the molar ratio of amino groups (-NH_2):isocyanate groups (-NCO) is 0.7 to 1.3:1. Composition.