JPH0291172A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain the title composition improved in adhesion to rubber, fiber or the like and giving a coating film improved in abrasion resistance by mixing a specified urethane prepolymer with a hydroxylic curing agent, a fluorocarbon resin, a silicon oil, a halogenating agent and a solvent. CONSTITUTION:An NCO-containing urethane prepolymer (A) is obtained by reacting a polyol (e.g., polyoxypropylene glycol of a number-average MW of 800-6000) with a caster oil polyol and a polyisocyanate (e.g., 4,4'-diphenylmethane diisocyanate) at 50-130 deg.C for 60-360min in a nitrogen gas. 100 pts.wt. component A is mixed with a hydroxylic curing agent (B) in a molar ratio (NCO/OH) (wherein NCO is the NCO groups of component A and OH is the OH groups of component B) of 0.7-1.3, 2-100 pts.wt. fluorocarbon resin (C) (e.g., polytetrafluoroethylene), 5-100 pts.wt. silicone oil (D) (e.g., dimethylsilicone oil), 0.002-20 pts.wt. halogenating agent (E) (e.g., trichloroisocyanuric acid) and 10-90 pts.wt., per 100 pts.wt. obtained composition, solvent (F).

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. [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 Rubber and cotton such as (NBR), isoprene rubber (IR), ethylene-propylene-diene copolymer rubber (EPDM), and ethylene-propylene copolymer rubber (EPM),
For surface coatings such as rayon and ABSSPS, resin-based paints such as nylon, epoxy, acrylic, and acrylic-ethylene copolymer, 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 objects coated with rubber, synthetic resins, fibers, etc., so the paints may peel off from the objects being coated, or the paint may not be coated properly. There was a problem that the abrasion resistance of the coated film was poor. 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 objects to be coated. [Means for Solving the Problems] In order to achieve the above object, the coating composition of the present invention contains a hydroxyl group based on 100 parts by weight of a urethane prepolymer comprising a polyol, a castor oil polyol, and a polyisocyanate and having an isocyanate group. The molar ratio of isocyanate groups to hydroxyl groups (-NC
O/-OH) is 0.7 to 1.3, 2 to 100 parts by weight of fluororesin, 5 to 100 parts by weight of silicone oil, and 0.002 to 20 parts by weight of halogenating agent. means are adopted. [Detailed Description of Means] First, the urethane prepolymer 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), and propylene oxide adduct of sucrose. Examples include compounds such as The above polyoxypropylene glycol has a number average molecular weight of 80
The range of 0 to 6000 is preferable. Polyisocyanate is a compound having multiple isocyanate 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, 80/2
0 tolylene diisocyanate, 4. 4'-Diphenylmethane diisocyanate (MDI), dianisidine diisocyanate, tridene diisocyanate, hexamethylene diisocyanate, metaxylene diisocyanate, 1,5-naphthalene diisocyanate (NDI),
(IPDI ), 4.4',
4"-) liphenylmethane triisocyanate, tris(p-isocyanate phenyl) thiophosphate, etc. are used. Next, the components to be added to the above urethane prepolymer will be explained. The curing agent has a hydroxyl group, and the above urethane It cures prepolymers, such as ethylene glycol, propylene glycol, butanediol, bentanediol, hexanediol, heptanediol, octanediol, diethylene glycol, triethylene glycol, dithioglycol, dipropylene glycol, neopentyl glycol, 2- Ethyl-S'-n-butyl-1,3-propanediol, 2,2,4-trimethyl-1,3-bentanediol, triethanolamine, glycerin, trimethylolpropane, etc. are used. The amount used is such that the molar ratio (-NCO/-OH) of the isocyanate group (-NCO) in the urethane prepolymer to the hydroxyl group (-OH) in the curing agent is 0.7 to
The amount is 1.3. Wear resistance decreases both when the molar ratio is less than 0.7 and when it exceeds 1.3. 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 based on 100 parts by weight of the urethane prepolymer. If it is less than 2 parts by weight, the resulting coating film will have poor abrasion resistance, 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 the silicone oil is 5 to 100 parts by weight based on 100 parts by weight of the urethane prepolymer. If the amount is less than 5 parts by weight, the wear resistance cannot be improved. Furthermore, even if the amount exceeds 100 parts by weight, the effect of improving wear resistance remains the same, but the adhesion deteriorates on the contrary. As a halogenating agent, N-promsuccinimide (N
Acid imide halogen compounds such as BS, N-bromphthalimide, isocyanuric acid halides such as trichloroisocyanuric acid (TCIA) and dichloroisocyanuric acid, halogenated hydantoins such as dichlorodimethylhydantoin, and alkyl hypohalides are used. The above-mentioned alkyl hypohalides are normal, secondary or tertiary alkyl hypohalides, particularly stable tertiary alkyl chlorides and bromides, such as tertiary butyl hypochloride (t-BHC), tertiary butyl hypohalides, Preferred are butylhypobromide, tertiary amylhypobromide, and the like, and halogen-substituted alkylhypochlorides such as dichloro, trichloro, or fluoromethylhypochloride can also be used. The halo and dunning agent are the urethane prepolymer 100
2 to 20 parts by weight of O, OO are arranged per part by weight. If the blending ratio is less than 2 parts by weight of O, OO, the degree of chlorination 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. Solvents that may be used as desired include benzene, toluene, xylene, ethylbenzene, ethylene chloride, dimethylformamide (DMF), dimethyl sulfoxide, methyl ethyl ketone, atocene, methyl isopropyl ketone, methyl isobutyl ketone, methyl acetate, ethyl acetate, and acetic acid. Isopropyl, n-butyl acetate, isobutyl acetate, anisole, tetrahydrofuran, methylene chloride, 1.1.1-)lychloroethane, n-hexane, cyclohexane, 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, castor oil polyol, polyisocyanate and necessary solvent are appropriately selected and mixed,
This was heated in dry nitrogen gas at 50-130°C and 60-360°C.
A urethane prepolymer having isocyanate groups is prepared by reacting for minutes. Next, the curing agent was added to 100 parts of this urethane prepolymer so that the molar ratio of isocyanate groups (-NCO) to hydroxyl groups (-OH) (-NCO/-01-1) was 0.
．． 7 to 1.3, 2 to 100 parts by weight of fluororesin, 5 to 100 parts by weight of silicone oil, and 0.002 to 20 parts by weight of halogenating agent were added, and a solvent was further added and passed through coating. Adjust to viscosity. 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 material to be coated is halogenated, and is made of polyol, castor oil polyol, and polyisocyanate, and is produced by the reaction of a urethane prepolymer having isocyanate groups with a curing agent. Due to the properties of the polyurethane having a specific structure having incyanate groups or hydroxyl groups, Improves adhesion to objects. [Examples 1 to 16 and Comparative Examples 1 to 101 Below, examples embodying the present invention will be described in comparison with comparative examples. First, the object to be coated is a vulcanized product as shown below. That is, the vulcanizate contained 100 parts by weight of BPDM (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: Taper type rotary abrasor (manufactured by Toyo Seiki Seisakusho Co., Ltd.) Test conditions: Wear wheel: H-22, load + 1 kg Wear rotation speed: 60 rpm Affected sample size: 100 mm x 100 mm Number of times of wear: Too many times Example 2 In Examples 1 to 16, each coating composition was applied to an object to be coated and dried in the same manner as in Example 1, and then subjected to the same abrasion resistance test as in Example 1. (Example 1) First, a urethane prepolymer was manufactured as follows. PPG2000 (weight average molecular weight 2000) 100
parts, castor oil polyol (hydroxyl value 80) 100 parts, M
75 parts of DI and 140 parts of trichlorethylene were mixed and reacted in dry nitrogen at 80° C. for 3 hours to obtain a urethane prepolymer. Next, for 100 parts of this urethane prepolymer, 1.
18 parts of 4-butanediol, 10 parts of fluororesin, dimethyl silicone oil [Kinematic viscosity: 10,000 centistokes (
A coating composition was obtained by mixing 10 parts of CsL)) and 1 part of TCIA. Applying this coating composition to the vulcanizate as the object to be coated,
It was dried at 80°C for 20 minutes. Regarding this, a wear resistance test was conducted. The results are shown in Table 1 below. (Example 2) In Example 1 above, the amount of MDI used was 100 parts, and 18 parts of 1,4-butanediol was replaced with 21.6 parts of ethylene glycol. A composition was obtained. (Example 3) Same as Example 1 except that the amount of MDI used was 125 parts and 1,6-hexanediol was 47.2 parts instead of 18 parts of 1,4-butanediol. A coating composition was obtained in the same manner. (Example 4) In Example 1, 10 parts of dimethyl silicone oil (kinematic viscosity 10,000 centistokes (Cst)) was replaced with dimethyl silicone oil (kinematic viscosity 60,000 Cst).
) A coating composition was obtained in the same manner as in Example 1 except that the amount was changed to 15 parts. (Example 5) Example 1 was repeated except that 2 parts of dimethyl silicone oil (kinematic viscosity 100,000 C5t) was used instead of 10 parts of dimethyl silicone oil (kinematic viscosity 100,000 Cst) in Example 1. A coating composition was obtained in the same manner. (Example 6) In Example 1, 100 parts of PPG2000 (weight average molecular weight 2000) and 100 parts of castor oil polyol (hydroxyl value 80) were replaced with 50 parts of PPG2000 (weight average molecular weight 2000) and castor oil polyol (
A coating composition was obtained in the same manner as in Example 1 except that the hydroxyl value was 80) and 150 parts. (Example 7) In the above Example 1, 150 parts of PPG2000 (weight average molecular weight 2000) and castor oil polyol (
A coating composition was obtained in the same manner as in Example 1 except that the hydroxyl value was 80) and 50 parts. (Example 8) A coating composition was obtained in the same manner as in Example 1, except that 80 parts of castor oil polyol (hydroxyl value 8G) was used instead of 100 parts of castor oil polyol (hydroxyl value 80) in Example 1. . (Example 9) A coating composition was obtained in the same manner as in Example 1, except that 70 parts of castor oil polyol (hydroxyl value 92) was used instead of 100 parts of castor oil polyol (hydroxyl value 80) in Example 1. . (Example 10) In Example 1, 100 parts of PPG2000 (weight average molecular weight 2000), 100 parts of castor oil polyol (hydroxyl value 80), 75 parts of MD I, and 140 parts of trichlorethylene were replaced with propylene oxide addition of glycerin. body (weight average molecular weight 3000) 150 parts,
Castor oil polyol (hydroxyl value 80) 150 parts, TD1
Except for using 104 parts and 200 parts of trichlorethylene.
A coating composition was obtained in the same manner as in Example 1. (Example 11) In Example 1, instead of 100 parts of PPG2000 (weight average molecular weight 2000), 100 parts of castor oil polyol (hydroxyl value 80), 75 parts of MD I, and 140 parts of trichlorethylene, trimethylolpropane was used. Propylene oxide adduct (weight average molecular weight 3000
) 250 parts, castor oil polyol (hydroxyl value 86) 50
A coating composition was obtained in the same manner as in Example 1, except that 1150 parts of MD, 225 parts of trichlorethylene were used. (Example 12) A coating composition was obtained in the same manner as in Example 1 except that 1 part of TCIA was changed to 0.002 parts. (Example 13) A coating composition was obtained in the same manner as in Example 1 except that 1 part of TCIA was changed to 0.1 part. (Example 14) A coating composition was obtained in the same manner as in Example 1 except that 1 part of TCIA was changed to 20 parts. (Example 15) In Example 1, t-BHC was used instead of TCIA.
A coating composition was obtained in the same manner as in Example 1 except that . (Example 16) A coating composition was obtained in the same manner as in Example 1 except that NBSI was used instead of TCIA. In addition, as a comparative example, the following coating compositions were used as f) H
JL, a test piece was prepared using it, and the abrasion resistance test was conducted on the test piece. The results are shown in Table 2 below. (Comparative Example 1) 100 parts of liquid polybutadiene (trade name: Idemitsu Seal AB-700W, manufactured by Idemitsu Petrochemical Industries, Ltd.) and parts of MDIIO were mixed to prepare a paint. This paint was applied to the object to be coated and cured at room temperature to prepare a test piece. (Comparative Example 2) Liquid polybutadiene (trade name Idemitsu Seal AB-100 manufactured by Idemitsu Petrochemical Industries Co., Ltd.) l 0 parts, MDI
The IO parts were mixed to prepare a paint. This paint was applied to the object to be coated and cured at room temperature to prepare a test piece. (Comparative Example 3) A 70% methanol solution of N-methoxymethylated nylon (trade name: Torezin M-20, manufactured by Teikoku Kagaku Sangyo Co., Ltd.) was applied to the coated object and cured at room temperature to prepare a test piece. (Comparative Example 4) Epoxy 4! (100 parts of fat (trade name Araldite PZ820 manufactured by Nippon Ciba Geigy Co., Ltd.), polyaminoamide (trade name Hardener H2 manufactured by Nippon Ciba Geigy Co., Ltd.)
) were mixed to prepare a paint. This paint was applied to the object to be coated and cured at room temperature to prepare a test piece. (Comparative Example 5) 100 parts of epoxy resin (trade name: Araldite GY250, manufactured by Nippon Ciba Geigy Co., Ltd.), polyaminoamide (
Product name Hardener H2)3 manufactured by Nippon Ciba Geigy Co., Ltd.
0 parts were mixed to prepare a paint. This paint was applied to the object to be coated and cured at room temperature to prepare a test piece. (Comparative Example 6) As a paint, a 74% toluene solution of chloroprene rubber (trade name: Bond G2, manufactured by Konishi Co., Ltd.) was applied to the object to be coated, and cured at room temperature to prepare a test piece. (Comparative Example 7) SBR (trade name: Diabond 5010, manufactured by Nogawa Chemical Co., Ltd.) was applied to the coated object and cured at room temperature to prepare a test piece. (Comparative Example 8) As a paint, an acrylic resin emulsion with a non-volatile content of 70% (trade name Diabond DA manufactured by Nogawa Chemical Co., Ltd.) was used.
-830A) was applied to the object to be coated and cured at room temperature to prepare a test piece. (Comparative Example 9) As a paint, an acrylic-ethylene modified emulsion (manufactured by Sunstar Chemical Co., Ltd., trade name: Penguin Cemen 1-138) with a non-volatile content of 55% was applied to the object, cured at room temperature, and a test piece was prepared. Created. (Comparative Example 10) As a paint, a polyurethane paint (trade name: Diabond DA700E, manufactured by Nogawagamical Co., Ltd.) was applied to the object to be coated and cured at room temperature to prepare a test piece. Table 2 Table 1 As can be seen from Table 1 above, the paint compositions of each example had an abrasion loss of 3.3% even after 1000 abrasion tests.
2-4. Onag and extremely small amounts. The reason why the coating compositions of each example exhibit such excellent wear resistance is presumed to be based on the lubricity of silicone oil, the low coefficient of friction characteristic of fluororesin, and the like. In addition, in the coating compositions of each example, the halogenating agent halogenates the object to be coated, and the curing agent reacts with a urethane prepolymer having an incyanate group consisting of a predetermined amount of polyol, castor oil polyol, and polyisocyanate. Based on the properties of the obtained polyurethane having isocyanate groups or hydroxyl groups, it exhibits excellent adhesion to the vulcanized rubber to be coated. On the other hand, as can be seen from Table 2, the paint compositions of each comparative example had a low abrasion loss of 482~b and had poor abrasion resistance.

【Effect of the invention】

The coating composition of the present invention has the effect that the resulting coating film has very good abrasion resistance and also has excellent adhesion to the object to be coated.

Claims (1)

[Claims] 1. For 100 parts by weight of a urethane prepolymer having isocyanate groups, which is made of polyol, castor oil polyol, and polyisocyanate, a curing agent containing hydroxyl groups is added at a molar ratio of isocyanate groups to hydroxyl groups (-NCO/-OH) of 0. 7 to 1.3, 2 to 100 parts by weight of fluororesin, and 5 to 1 part of silicone oil.
A coating composition containing 0.00 parts by weight and 0.002 to 20 parts by weight of a halogenating agent.