JPH0211679A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain a coating composition which is improved in abrasion resistance of coating film and adhesion to substrate by mixing a urethane prepolymer obtained from a polyol and a polyisocyanate with a curing agent, a fluorocarbon resin, a silicone oil and a halogenating agent in a specified ratio. CONSTITUTION:A polyol such as polyoxypropylene glycol is reacted with a polyisocyanate such as 2,4-tolylene diisocyanate to obtain an isocyanate urethane prepolymer. A coating composition is obtained by mixing 100 pts.wt. this urethane prepolymer with a hydroxylic curing agent, such as ethylene glycol, in an amount to give a molar ratio of the isocyanate groups to the hydroxyl groups (-NCO/-OH) of 0.7-1.3, 2-100 pts.wt. fluorocarbon resin such as polytetrafluoroethylene, at least 2 pts.wt. silicone oil such as dimethylsilicone and 0.002-20 pts.wt. halogenating agent such as t-butyl hypochlorite. 10-90 pts.wt. solvent such as benzene is optionally added to 100 pts.wt. coating composition in the above mixing.

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-
Synthetic rubber such as propylene copolymer rubber (EPT), cotton,
Surface coatings such as Racon, ABS, PS, etc. are nylon-based,
Epoxy-based, acrylic-based, acrylic-ethylene copolymer-based resin 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 adherends 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 to provide a coating composition that provides a coating film with excellent abrasion resistance and good adhesion to adherends.

[Means for Solving the Problems] In order to achieve the above object, the coating composition of the present invention contains a curing agent containing a hydroxyl group per 1 part of 100ffi of a urethane prepolymer made of a polyol and a polyisocyanate and having an isocyanate group. The molar ratio of isocyanate groups to hydroxyl groups (-NCO/-OH) is 0.
7 to 1.3, 2 to 100 parts by weight of fluororesin,
At least 2 parts by weight of silicone oil and 0.0 parts by weight of halogenating agent.
002 to 20 parts by weight is 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 sig sugar. Examples include added compounds. The above polyoxypropylene glycol has a number average molecular weight of 8
A value in the range of 00 to 6000 is preferred.

Polyisocyanate is a compound having a plurality of isocyanate groups, such as 2,4-1-lylene diisocyanate (TDI), a ratio of 65/35 (2,4-lylene diisocyanate and 2,6-)lylene diisocyanate, and 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), hydrogenated 4,4'-diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, hydrogenated 2,4-tolylene 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.

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 2 parts by weight or more based on 100 parts by weight of the urethane prepolymer. If the amount is less than 2 parts by weight, the wear resistance cannot be improved.

Further, the upper limit thereof is not particularly limited, but is preferably 1 million parts by weight or less, and more preferably 100,000 parts by weight or less.

Even if it is blended in an amount exceeding 1 million parts by weight, the effect of improving wear resistance remains unchanged, but on the contrary, the adhesion deteriorates.

The curing agent has a hydroxyl group and cures the urethane prepolymer, such as ethylene glycol, propylene glycol, butanediol, bentanediol, hexanediol, heptanediol, octanediol, diethylene glycol, triethylene glycol, dithioglycol. , dipropylene glycol, neopentyl glycol, 2-ethyl-2-n-7
'Tyl-1,3-propanediol, 2,2,4-trimethyl-1,3-bentanediol, triethanolamine, glycerin, trimethylolpropane, etc. are used. The amount of the curing agent used is such that the no molar ratio (-NGO/-OH) of isocyanate groups (-NGO) in the urethane prepolymer to hydroxyl groups (-OH) in the curing agent is 0.
．． The amount is 7 to 1.3. Wear resistance decreases both when the molar ratio is less than 0.7 and when it exceeds 1.3.

Examples of halogenating agents include t-butylhypochloride (t-BHC) as an alkylhypohalide, sodium hypochlorite and potassium hypochlorite as hypohalites, and 100NX-bonds ( X is a halogen atom) as a compound having N-bromosuccinimide (
Among these, alkyl hypohalides, Hypochlorite or a compound having a -CONX- bond in the molecule is preferred.

The blending ratio of this halogenating agent is in the range of 0.002 to 20 parts by weight based on 100 parts by weight of the urethane prepolymer. If the proportion is less than 0.002 parts by weight, the degree of halogenation will be small and the adhesion of the coating will not improve much.
If it exceeds 20 parts by weight, the stability of the coating composition will deteriorate.

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. Examples include isopropyl, n-butyl acetate, isobutyl acetate, anisole, tetrahydrofuran, methylene chloride, 1,1,1-trichloroethane, n-hexane, and cyclohexane.

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, polyisocyanate, and necessary solvent are appropriately selected and mixed, and the mixture is reacted in dry nitrogen gas at 50 to 130°C for 60 to 360 minutes to prepare a urethane prepolymer having isocyanate groups.

Next, with respect to 100 parts by weight of this urethane prepolymer, a curing agent was added such that the molar ratio of isocyanate groups (-NCO) to hydroxyl groups (-OH) (-NCo/-OH) was 0.
7 to 1.3, 2 to 100 parts by weight of fluororesin, 2 parts by weight or more of silicone oil, 0.002 parts by weight of halogenating agent.
~20 parts by weight is added, and a solvent is further added to adjust the viscosity to a level suitable for coating.

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 adhesion to the object to be coated is improved due to the properties of polyurethane with a specific structure containing isocyanate groups or hydroxyl groups, which is made of polyol and polyisocyanate and is produced by the reaction between a horsetail-tanpre polymer having isocyanate groups and a curing agent.

[Examples 1-12 and Comparative Examples 1-10] 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 contained 100 parts by weight of EPDM (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, Testing machine: Taper type rotary abrenosaur (manufactured by Toyo Seiki Seisakusho Co., Ltd.) Test conditions: Wear wheel: H-22, Load: 1 kg Abrasion rotation speed: 60 rpm Usual sample size: 100n+mX100mm Abrasion count: 1000 times (Example) 1) First, a urethane prepolymer was produced as follows.

PPG2000 (weight average molecular weight 2000) 200
1, 75 parts of MD I, 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.
A coating composition was obtained by mixing 16.2 parts of 4-butanediol, 10 parts of a fluororesin, 10 parts of dimethyl silicone oil (having a kinematic viscosity of 10,000 centistokes (Cst) 3), and 91 parts of TCIAO.

Applying this coating composition to the vulcanizate as the object to be coated,
It was dried at 80''C for 20 minutes.A wear resistance test was conducted on this.The results are shown in Table 1 below.

(Example 2) A coating composition was obtained in the same manner as in Example 1 except that the amount of MDI used in Example 1 was changed to 100 parts.

Applying this coating composition to the object to be coated in the same manner as in Example 1,
Dry. Regarding this, a wear resistance test was conducted. The results are shown in Table 1 below.

(Example 3) A coating composition was obtained in the same manner as in Example 1 except that the amount of MDI used was 125 parts.

Applying this coating composition to the object to be coated in the same manner as in Example 1,
Dry. Regarding this, a wear resistance test was conducted. The results are shown in Table 1 below.

(Example 4) The same procedure as in Example 1 was carried out, except that 151 parts of dimethyl silicone oil (dynamic viscosity: 60,000 C5t) was used instead of 10 parts of dimethyl silicone oil (kinematic viscosity: 10,000 C5t) in Example 1. A coating composition was obtained.

Applying this coating composition to the object to be coated in the same manner as in Example 1,
Dry. Regarding this, a wear resistance test was conducted. The results are shown in Table 1 below.

(Example 5) In Example 1, except that 20 parts of dimethyl silicone oil (kinematic viscosity 100,000 Cst) was used instead of 20 parts of dimethyl silicone oil (kinematic viscosity 100,000 Cst). A coating composition was obtained in the same manner.

Applying this coating composition to the object to be coated in the same manner as in Example 1,
Dry. Regarding this, a wear resistance test was conducted. The results are shown in Table 1 below.

(Example 6) A coating composition was obtained in the same manner as in Example 1 except that 1-BHC was used in place of TCIA.

Applying this coating composition to the object to be coated in the same manner as in Example 1,
Dry. Regarding this, a wear resistance test was conducted. The results are shown in Table 1 below. ~ (Example 7) A coating composition was obtained in the same manner as in Example 1 except that NB51 was used in place of TCIA.

Applying this coating composition to the object to be coated in the same manner as in Example 1,
Dry. Regarding this, a wear resistance test was conducted. The results are shown in Table 1 below.

(Example 8) A coating composition was obtained in the same manner as in Example 1 except that the amount of TCIA used in Example 1 was changed to 0.002 parts instead of 0.1 part.

Applying this coating composition to the object to be coated in the same manner as in Example 1,
Dry. Regarding this, a wear resistance test was conducted. The results are shown in Table 1 below.

(Example 9) A coating composition was obtained in the same manner as in Example 1 except that the amount of TCIA used in Example 1 was changed to 1 part instead of 0.1 part.

Applying this coating composition to the object to be coated in the same manner as in Example 1,
Dry. Regarding this, a wear resistance test was conducted. The results are shown in Table 1 below.

(Example 10) A coating composition was obtained in the same manner as in Example 1, except that the amount of TCIA used in Example 1 was changed to 20 parts instead of 0.1 part.

Applying this coating composition to the object to be coated in the same manner as in Example 1,
Dry. Regarding this, a wear resistance test was conducted. The results are shown in Table 1 below.

(Example 11) In Example 1, 100 parts of PPG2000 (weight average molecular weight 2000), 175 parts of MD, 140 parts of trichlorethylene, 16.2 parts of 1.4-butanediol
300 parts of a propylene oxide adduct of glycerin (M weight average molecular weight approximately 3000), TD1104
A coating composition was obtained in the same manner as in Example 1, except that 200 parts of trichlorethylene and 20.5 parts of ethylene glycol were used.

Applying this coating composition to the object to be coated in the same manner as in Example 1,
Dry. Regarding this, a wear resistance test was conducted. The results are shown in Table 1 below.

(Example 12) In Example 1, 100 parts of PPG2000 (weight average molecular weight 2000), 75 parts of MD I, 140 parts of trichlorethylene, 16.
In place of 2 parts, 300 parts of a propylene oxide adduct of trimethylolpropane (weight average molecular weight: 3000), 1150 parts of MD, 225 parts of trichlorethylene, 1.
A coating composition was obtained in the same manner as in Example 1 except that 27 parts of 4-butanediol was used.

Applying this coating composition to the object to be coated in the same manner as in Example 1,
Dry. Regarding this, a wear resistance test was conducted. The results are shown in Table 1 below.

In addition, the following coating composition was used as a comparative example.

(Comparative Example 1) 100 parts of liquid polybutadiene (trade name: Idemitsu Seal AB-700W, manufactured by Idemitsu Petrochemical Industries Co., Ltd.), MD I 1
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. This test piece was subjected to the abrasion resistance test described above. The results are shown in Table 2 below.

(Comparative Example 2) 100 parts of liquid polybutadiene (trade name: Idemitsu Seal AB-100, manufactured by Idemitsu Petrochemical Industries, Ltd.) and part 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. This test piece was subjected to the abrasion resistance test described above. The results are shown in Table-2 below.
Shown below.

(Comparative Example 3) A 0% methanosif solution of N-methoxymethylated nylon (trade name: Torezin M-20, manufactured by Teikoku Kagaku Sangyo Co., Ltd.) was applied to the object to be coated and cured at room temperature to prepare a test piece. This test piece was subjected to the abrasion resistance test described above. The results are shown in Table 2 below.

(Comparative Example 4) 100 parts of epoxy resin (trade name: Araldite PZ820, manufactured by Nippon Ciba Geigy Co., Ltd.), polyaminoamide (
Product name Hardener H2) 1 manufactured by Nippon Ciba Geigy Co., Ltd.
00 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. This test piece was subjected to the abrasion resistance test described above. The results are shown in Table 2 below.

(Comparative Example 5) 100 parts of epoxy resin (trade name Araldite GY250, manufactured by Nippon Ciba Geigy Co., Ltd.), polyaminoamide (trade name Hardener Hz, manufactured by Nippon Ciba Geigy Co., Ltd.)
30 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. This test piece was subjected to the abrasion resistance test described above. The results are shown in Table 2 below.

(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. This test piece was subjected to the abrasion resistance test described above. The results are shown in Table 2 below.

(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. This test piece was subjected to the abrasion resistance test described above. The results are shown in Table 2 below.

(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. This test piece was subjected to the abrasion resistance test described above. The results are shown in Table 2 below.

(Comparative Example 9) As a paint, an acrylic-ethylene modified emulsion (manufactured by Sunstar Chemical Co., Ltd., trade name: Penguin Semen 138) with a non-volatile content of 55% was applied to the object to be coated and cured at room temperature to prepare a test piece. did.

This test piece was subjected to the abrasion resistance test described above.

The results are shown in Table 2 below.

(Comparative Example 10) As a paint, a polyurethane paint (trade name: Diabond DA700E, manufactured by Nogawa Chemical Co., Ltd.) was applied to the object to be coated and cured at room temperature to prepare a test piece. This test piece was subjected to the abrasion test described above. The results are shown in Table 2 below.

Table 1 Table 2 As can be seen from Table 1 above, the paint compositions of each example had an abrasion loss of 3.0% even after 1000 abrasion tests.
The amount is extremely small, ranging from 0 to 5.7 mg.

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 of fluororesin, etc.

In addition, the coating composition of each example has isocyanate groups or hydroxyl groups obtained by reacting a urethane prepolymer, which is made of a predetermined amount of polyol and polyisocyanate and has isocyanate groups, with a curing agent and the action of a halogenating agent. Due to the properties of polyurethane, it exhibits excellent adhesion to the vulcanized rubber that is coated.

On the other hand, as can be seen from Table 2, when the coating compositions of each comparative example were used, the abrasion loss was as large as 482 to 2290 mg, and the abrasion resistance was poor.

[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 adherends.

Claims (1)

[Claims] 1. For 100 parts by weight of a urethane prepolymer made of polyol and polyisocyanate and having isocyanate groups, 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. A coating composition comprising 2 to 100 parts by weight of a fluororesin, 2 parts by weight or more of silicone oil, and 0.002 to 20 parts by weight of a halogenating agent.