JPH0386774A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain a coating composition which provides good adhesion between a substrate and a coating film and is excellent in the abrasion resistance of a coating film surface by incorporating a halogenating agent and a silicone diol each in a specified amount into a specified polyurethane. CONSTITUTION:100 pts.wt. polyurethane which is prepared from a polyol (e.g. polyoxypropylene glycol), triethanolamine, and a polyisocyanate (e.g. tolylene diisocyanate) and in which the molar ratio of polyol to triethanolamine is 1:(0.05 to 2.0) and the molar ratio of OH to NCO is 1:(1.5 to 7), is mixed with 0.002-20 pts.wt. halogenating agent (e.g. isocyanuric trichloride) and a silicone diol [preferably a compound of the formula (wherein n is 1 to 20), having a hydroxyl number of 10 to 450 and an average molecular weight of 500 to 11,200] in an amount sufficient to provide a molar ratio of NCO to OH of 0.7 to 1.3, thus giving a coating composition. This composition provides good adhesion between a substrate, such as rubber, synthetic resin or fiber, and a coating film and is excellent in the abrasion resistance of a coating film surface.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a coating composition used for coating rubber products, synthetic resin products, etc. It is b. [Prior art 1] In general, natural rubber (NR), styrene-butadiene copolymer rubber (SDR), butadiene rubber (BR), isoprene-isobutylene copolymer rubber (IIRE), chloroprene rubber (CR), acrylonitrile-butadiene copolymer rubber ( NBR), isoprene rubber (IR), ethylene-
Rubbers such as propylene-diene copolymer rubber (EPDM), ethylene-propylene copolymer rubber (EPM), acrylonitrile-butadiene-styrene copolymer resin (ABS)
resin), synthetic resins such as polystyrene (PS), cotton,
For coatings such as rayon, resin-based paints such as nylon, epoxy resin, acrylic resin, and acrylic-ethylene resin, and rubber-based paints such as BR, CR, and SDR are used (
For example, Japanese Patent Application Laid-Open No. 1-131290). [Problems to be Solved by the Invention] However, the above-mentioned conventional paints have low adhesion between the coating material and the coating material such as rubber, synthetic resin, fibers, etc., and the paint itself does not have wear resistance. However, there was a problem in that the coating film surface lacked abrasion resistance. An object of the present invention is to provide a coating composition that has good adhesion between the coated object and the coating film and has excellent abrasion resistance on the coating surface. [Means for Solving the Problems] In order to solve the above problems, the present invention uses polyols,
It consists of triethanol ξ and polyisocyanate, and the molar ratio of polyol/triethanol ξ is 110.
．． 05 to 2.0, and the molar ratio of hydroxyl group (-OH)/isocyanate group (-NGO) is 1/1.5.
~7 to 100 parts by weight of polyurethane, 0.002 to 20 parts by weight of the halogenating agent, and silicone diol containing incyanate groups (-NCO)/hydroxyl groups (-0
A method is adopted in which the molar ratio of H") is blended in an amount of 0.7 to 1.3. [Detailed explanation of the method] First, polyurethane will be explained. As polyols, polyoxypropylene glycol, polyoxypropylene glycol, A propylene oxide adduct of glycerin, a propylene oxide adduct of pentaerythritol, a compound obtained by adding propylene oxide to C!sugar, etc. can be used.The above polyoxypropylene glycol has a number average molecular weight in the range of 800 to 6,000. The amine is triethanolamine, and monoethanolamine and diethanolamine cause a crosslinking reaction.
It is unsuitable because polyurethane gels. Polyisocyanate is a compound having a plurality of isocyanate groups, and examples of aromatic polyisocyanates include tolylene diisocyanate (TDI), 1,5-naphthalene diisocyanate (NDI), xylylene diisocyanate (XDI), and 4,4'-diphenylmethane. 4.4'-methylenebis(cyclohexyl isocyanate) (H -MDI), hexahydroxylylene diisocyanate, and 1,6-hexamethylene diisocyanate as the aliphatic polyisocyanate. The molar ratio of the polyol/polyol to triethanolamine is 110.05 to 2.0. This ratio is 0.
If it is less than 0.05 or more than 2.0, the adhesion between the coating film and the object to be coated will decrease. Further, the molar ratio of hydroxyl group (-OH) in the polyol/isocyanate group (-NCO) in the polyisocyanate is 1/1.5 to 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 between the coating film and the object to be coated decreases, and adhesion may not occur. The polyurethane base is produced, for example, by mixing the polyol, polyol, triethanolamine, and polyisocyanate, and reacting the mixture at 80° C. for 3 hours in a nitrogen gas atmosphere. Next, as a halogenating agent, for example, t-butylhypochloride (t-BHC) is used as an alkylhypohalide.
), sodium hypochlorite, calicum hypochlorite as hypohalites, N-bromosuccinimide (NBSI), isocyanuric trichloride (TCIA), dichloride as compounds having -CONX- bond in the molecule Examples include isocyanuric m (DicIA), antimony fluoride, and a mixed solution consisting of sulfur fluoride and bromine. Compounds are preferred. The blending ratio of this halogenating agent is as follows:
The range is 2 to 20 parts by weight of O,OO relative to 0 parts by weight. If the blending ratio is less than 2 parts by weight of O or OO, the degree of halogenation is small, so that there is little improvement in adhesion, and if it exceeds 20 parts by weight, the stability of the coating composition deteriorates. Next, silicone diol is a compound having functions as a curing agent and a chain extender for the polyurethane, and is represented by the following general formula. CH3CH3 5i -(CH2)nOH CH3 However, n is 1 to 20. Hydroxyl number is 10-450,
The average molecular weight is 500-11200"t'. The blending ratio of this silicone diol is such that the molar ratio of isocyanate groups in the polyurethane/hydroxyl groups in the silicone diol is 0.7 to 1.3 with respect to 100 parts by weight of the polyurethane. If this amount is less than 0.7 or more than 1.3, the adhesion of the coating film to the object to be coated will decrease.The coating composition of the present invention may optionally contain a solvent, a fluororesin, etc. Examples of the solvent include n-hexane, n-heptane, and n-octane as aliphatic hydrocarbons, cyclohexane and cyclooctane as alicyclic hydrocarbons, and benzene, ethylbenzene, and aromatic hydrocarbons. toluene, xylene,
Ketones include acetone, methyl ethyl ketone, ethyl propyl ketone, and methyl butyl ketone; ethers include tetrahydrofuran; acetic esters include methyl acetate, ethyl acetate, and isopropyl acetate; halogenated hydrocarbons include methylene chloride; 1,1. -1-Trichloroethane, trichloroethylene, dimethylsulfoxide (DMSO), dimethylformamide, etc. can be used. These solvents can be used alone or as a mixed solvent of two or more. The blending ratio of this solvent is 3 in 100ffi of the coating composition.
A wide range of 95 parts by weight may be used. If the same proportion is less than 3 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 leading to a decrease in adhesion; if it exceeds 95 parts by weight, the opposite will occur. As the solid content decreases, the film thickness of the coating composition becomes thinner, and adhesion tends to decrease. Further, as the fluororesin, polytetrafluoroethylene, trifluoroethylene, vinylidene fluoride, etc. can be used. The blending ratio is 10% of the polyurethane mentioned above.
A range of 2 to 100 parts by weight is suitable for 0 parts by weight. If it is less than 2 parts by weight, the improvement in abrasion resistance will be small, and if it exceeds 100 parts by weight, it will be difficult to apply the coating composition. In the coating composition of the present invention, the halogenating agent is contained in an amount of 0.002 to 20 parts by weight, and the silicone diol is contained in a molar ratio of isocyanate groups/hydroxyl groups of 0.7 to 1.3 with respect to 100 parts by weight of the polyurethane. It is obtained by blending according to a conventional method.

[Operation] By adopting the above means, the halogenating agent in the coating composition halogenates the object to be coated, thereby increasing the intermolecular force between the coating film and the object to be coated, thereby improving adhesion. At the same time, it is presumed that the silicone diol hardens the polyurethane, increases its molecular weight, increases the rigidity of the polyurethane, and lowers the coefficient of friction of the coating surface, thereby improving wear resistance. [Examples 1 to 12 and Comparative Examples 1 to 51] Examples embodying the present invention will be described below in comparison with comparative examples. In addition, in each of the following, parts by weight are abbreviated as parts. First, polyol (PO), triethanolane (TEA), and polyisocyanate (PI) shown in Table 1 below are used.
) 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%. Abbreviations in Table 1 other than those mentioned above have the following meanings. 1”PG 3000: Polypropylene glycol with a number average molecular weight of 3000 PPG 1000: Polypropylene glycol with a number average molecular weight of 1too0 PPG 2000: Polypropylene glycol with a number average molecular weight of 12000 TG 3000: Triethylene glycol with a number average molecular weight of 3000 TG 1000: Number average molecular weight 13000 Triethylene glycol TG 2000: Triethylene glycol with a number average molecular weight of 1i3000 Next, halogenating agents and silicone diols shown in Tables 2 and 3 below are blended with 100 parts of the solid content of the above polyurethane to make a paint. A composition was obtained.This coating composition was applied to the following coated object to prepare a test piece.Coating object: 00 parts of EPDMI, 70 parts of carbon black
Vulcanized rubber obtained by vulcanizing a rubber compound containing 35 parts of mineral oil, 7 parts of zinc white, 2 parts of stearic acid, 2 parts of vulcanization accelerator, and 1.5 parts of sulfur at 160°C for 30 minutes. Regarding this test piece, an abrasion resistance test was conducted to measure the abrasion loss under the following test conditions. The results are also shown in Tables 2 and 3. Test machine: Tipper type rotary abrader (manufactured by Toyo Seiki Seisakusho Co., Ltd.) Test conditions: Wear wheel: H-22, load: 1 kg
Wear rotation speed: 60 rpm Sample size: 100III 11 x 1001 IIaI Wear rotation: 1000 times ■~■ in the polyurethane column in Table-2 and Table-3 correspond to ■~■ in Table-1 above Represents polyurethane,
Silicone diol represents the following meaning. (a): Hydroxyl value 112, average molecular weight 1000~
): Hydroxyl number 62, average molecular weight 1800 (C):
Hydroxyl number: 35, average molecular weight: 3200 (d): Hydroxyl number: 20, average molecular weight: 5600 As seen from Tables 2 and 3 above, the abrasion loss of Examples 1 to 12 was 5.
．． The wear resistance is very low at 2 to 9.8 towns/1000 times, and it has excellent wear resistance. On the other hand, when the blending ratio of the halogenating agent is too low (Comparative Example 1)
, 3) has a wear loss of 1873.3 to 1945.0 m.
g/1000 times, and when the blending ratio of the halogenating agent is excessive (Comparative Example 2.4), the coating composition gels, and when the halogenating agent and silicone diol are not blended (Comparative Example 5) ) has a wear loss of 2438.6m.
g/1000 times, which is very large. The reason why the coating composition of the present invention exhibits the above-mentioned excellent abrasion resistance is that the halogenating agent in the coating composition halogenates the vulcanized rubber, which is the object to be coated, so that the coating film and vulcanization This is thought to be because the intermolecular force between the polyurethane and the rubber increases, improving adhesion, and the silicone diol hardens the polyurethane, increasing the rigidity of the polyurethane and lowering the coefficient of friction on the surface of the coating film. [Effects of the Invention] The coating composition of the present invention has the advantage that the adhesion between the object to be coated and the coating film is good, and the abrasion resistance of the coating film surface is excellent.

Claims (1)

[Claims] 1. Consists of polyol, triethanolamine, and polyisocyanate, with a polyol/triethanolamine molar ratio of 1/0.05 to 2.0, and a hydroxyl group (
-OH)/isocyanate group (-NCO) molar ratio is 1
/1.5 to 7 for 100 parts by weight of polyurethane,
A coating composition comprising 0.002 to 20 parts by weight of a halogenating agent and a silicone diol in an amount such that the molar ratio of isocyanate groups (-NCO) to hydroxyl groups (-OH) is 0.7 to 1.3.