JPH0459837A - Resin composition for rubber coating - Google Patents

Abstract

PURPOSE:To obtain the title composition consisting essentially of a terminal isocyanate urethane prepolymer and a specific compound, capable of providing soft and tough cured film and strongly adhering on rubber surfaces. CONSTITUTION:The objective composition containing (A) a terminal isocyanate urethane prepolymer obtained from a polyol (preferably being polypropylene glycol having 200-4000 molecular weight), and stoichiometrically excess polyisocyanate (preferably diphenylmethane-4,4'-diisocyanate) and (B) a compound expressed by the formula ((n) is 2-4), preferably at a weight ratio of A:B of 1:0.005 to 1:0.1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a resin composition for coatings applied to rubber surfaces.

[Prior Art] Because rubber has excellent elastic properties, it is widely used as a cushioning material, typified by fenders used in ports. However, rubber usually has a black color and is poor in aesthetics, and its weather resistance is poor and its surface deteriorates when exposed outdoors, causing problems such as contaminating ships and the like that come into contact with it. In order to compensate for these problems, a paint that can be applied to the rubber surface has been desired, but one that can withstand practical use has not yet been developed.

[Problems to be Solved by the Invention] Flexibility that can sufficiently follow the movement of rubber and strong adhesion to the rubber surface are the most important characteristics imposed on a resin composition for rubber coatings, and the present invention solves these problems. The present invention provides a composition exhibiting such properties.

[Means for Solving the Problems] As a result of intensive studies in view of these points, the present inventors have found that:
We have arrived at the present invention. That is, the present invention is a resin composition for a rubber coating comprising (A) a terminal isocyanate urethane prepolymer made from a polyol and a stoichiometrically excess polyisocyanate, and (B) a compound of the general formula as essential components.

Component (B) in the present invention includes terephthalyl chloride, isophthalyl chloride, phthalyl chloride, 1,2゜4-benzenetricarboxylic acid trichloride, 1,2゜3-benzenetricarboxylic acid trichloride, 1,3゜5-
Benzenetricarboxylic acid trichloride, 1,2°3,4-benzendetracarboxylic acid tetrachloride, and the like can be used. Among these, preferred is terephthalyl chloride.

The raw material polyol for the urethane prepolymer (A) in the present invention includes polymer polyols such as polyether polyols, polyester polyols, polymer polyols, polybutadiene polyols, and polyether polyols including mixtures of two or more thereof. is a low-molecular polyol (trifunctional polyol such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol; at least two such as amines (alkanolamines such as triethanolamine; aliphatic polyamines such as ethylenethiamine; aromatic polyamines such as tolylene diamine, methylene dianiline, polymethylene polyphenyl amine, etc.); Alkylene oxide (alkylene oxide having 2 to 4 carbon atoms, e.g. ethylene oxide, propylene oxide, butylene oxide, etc.) adducts of compounds having an active hydrogen atom, ring-opening polymers of alkylene oxides (ring-opening polymerization of tetrahydrofuran, polyhydrolysis) polyester polyols include polycarboxylic acids (aliphatic polycarboxylic acids such as adipic acid, maleic acid, dimerized sulfuric acid, aromatic polycarboxylic acids such as phthalic acid) and polyols (such as those mentioned above). Polyester polyols, lactone polyesters (such as polycaprolactone polyols) obtained by condensation with low molecular weight polyols or polyether polyols such as (acrylonitrile and/or styrene, etc.); polyether polyols include those obtained by polymerizing butadiene with a hydroxyl group-containing radical initiator, and those obtained by polymerizing butadiene with an anionic polymerization catalyst such as sodium or lithium. Examples include those obtained by adding a compound that becomes a hydroxyl group, such as ethyleneoxy r, to an active end polymer obtained by polymerizing butadiene.
' Among these polymer polyols, polyether polyols are preferred, and polypropylene glycol is particularly preferred.

The molecular weight of high molecular weight polyol is usually 200~e o oo
, preferably 200 to 4000. Molecular weight is 5oo
If a polymer polyol larger than O is used, the resin strength after curing will be weakened, making it impossible to obtain a tough paint film.

The (average) functional group number of the polyol is usually 1.8 to 4, preferably 2 to 3, particularly preferably 2 to 2.5.

In the present invention, the polyisocyanates used as raw materials for the prepolymer of component (A) include aromatic polyinsyanates, such as 2,4-)lylene diisocyanate, 2,8-tolylene diisocyanate, and 2,4-
Tolylene diisocyanate and 2. mixtures with tolylene diisocyanate; 1.3-bis(phenylmethyl)benzene-4,4',4'-triisocyanate, etc.; aliphatic polyisocyanates; common aliphatic polyisocyanates such as hexamethylene diinocyanate;
Aroaliphatic polyisocyanates such as xylylene diisocyanate; cycloaliphatic polyisocyanates such as isophorone diisocyanate, cyclohexane! , 4-
Examples include diisocyanate, 1,4-methylenebis(cyclohexyl isocyanate), and mixtures of two or more thereof. Among these, aromatic polyisocyanates are preferred, and diphenylmethane-4,4'-diisocyanate is particularly preferred.

The prepolymer (A) in the present invention is obtained by reacting the above-mentioned polyol and polyisocyanate in a proportion that produces an incyanate-terminated prepolymer (a proportion that produces a stoichiometric excess of incyanate),
The equivalent ratio (NGO10H ratio) is usually 7 to 0.9, preferably 5 to 2.

Urethane prepolymer (A) is usually obtained by reacting the above polyol and polyisocyanate at 70 to 110°C for 1 to 20 hours. The incyanate group content of the urethane prepolymer is usually 5 to 20% by weight, preferably 7 to 12% by weight.

The ratio of component (A) and component (B) is usually l:o by weight.
, oos to 1:0.2, preferably 1:0.00
5-1: 0.1.

In the present invention, in addition to components (A) and (B), a crosslinking agent, a catalyst, and an additive may be added as necessary.

In addition to the above-mentioned low-molecular-weight polyol, 4゜4' can be used as a crosslinking agent.
-methylenebis(2-chloroaniline), 4. ．． Aromatic polyamines such as 4m methylenebis(2,3-dichloroaniline) and 3.5=diamino-4-chloro-methyl-benzoate can be used. Among these, aromatic polyamines are preferred, and 4.4 is particularly preferred.
'-methylenebis(2-chloroaniline). The ratio of the prepolymer of component (A) to the crosslinking agent is usually 1:0 to 1:1.5 in equivalent ratio, preferably 1:0 to 1:0.
．． It is 9.

Catalysts include amine catalysts such as triethylamine, triethylenediamine, N,N'-dimethylpiperazine and N-ethylmorpholine; acid catalysts such as octylic acid, adipic acid and azelaic acid; metal catalysts such as dibutyltin dilaurate, dibutyltin malate,
Examples include stannath octoate, bismuth chloride, lead octylate, and ferric acetylacetonate; and combination systems of two or more of these. Among these, metal catalysts are preferred, and dibutyl tin malate is particularly preferred.

Additives include reinforcing agents (carbon black, white carbon, colloidal silica, etc.), inorganic fillers (calcium carbonate, barium sulfate, talc, clay, silica powder, etc.), and plasticizers (dibutyl phthalate, dioctyl phthalate, chlorinated normal). (paraffin, etc.), diluents (petroleum resin, xylene resin, etc.), solvents (toluene, xylene, methyl ethyl ketone, ethyl acetate, etc.), anti-aging agents, flame retardants, and colorants.

Rubbers to which the composition of the present invention can be applied include, for example, natural rubber, poly, imbutylene rubber, styrene butadiene rubber, polybutadiene rubber, butyl rubber, chloroprene rubber, polyurethane rubber, and the like.

The amount of the composition of the present invention used is usually 20 to 300 grams per m'' of rubber surface area, preferably 50 to 300 grams.

In the present invention, the order of application is completely arbitrary as long as components (A) and (B) are essential components.

(A), (B) and optional components added as necessary are mixed in advance and applied simultaneously to the rubber surface, (B) or (B) diluted with a solvent is first applied to the rubber surface, Any method may be used, such as sequential coating in which (A) or a mixture of (A) and optional components added as necessary are applied. Furthermore, the application method is not limited and can be arbitrarily selected from dipping, brushing, roller coating, spraying, and the like.

After application, component (A) in the present invention reacts with moisture in the atmosphere or with the moisture in the atmosphere and an optionally added crosslinking agent to form a flexible and tough film.

[Action] The exact mechanism of action of component (B) is unknown, but by acting on the unsaturated bonds of rubber molecules and increasing the polarity of the surface, it increases the interaction between the rubber and urethane resin interface, and improves the rubber/paint film. It is estimated that this contributes to improving the adhesion between the parts.

[Example] The present invention will be further explained below with reference to Production Examples and Examples, but the present invention is not limited thereto. The parts described below indicate parts by weight.

Production Example 1 In a 4-bottle flask equipped with a stirring bar and a thermometer, a number average molecular weight of 3000. 725 parts of polypropylene glycol having a functional group number of 2 was added, and 1 g of 3 intestines was added under reduced pressure.
It was heated to 10°C and dehydrated for 1 hour. Next, 275 parts of diphenylmethane-4,4'-diisocyanate was added and reacted at 100° C. for 3 hours under a nitrogen stream to obtain prepolymer [A 11]. The isocyanate content of prepolymer [A1] was 7.2%.

Production Example 2 550 parts of polypropylene glycol with a number average molecular weight of 20 Gol functional group number 2 and a multi-year average molecular weight of 10,001 were placed in a four-bottle flask equipped with a stirring bar and a thermometer.
85 parts of polypropylene glycol having a functional group number of 3 was added, and the mixture was heated to 0° C. under a reduced pressure of 3 mHg for dehydration for 1 hour. Next, 275 parts of diphenylmethane-4,4'-diisocyanate was added and reacted at 100° C. for 5 hours under a nitrogen stream to obtain prepolymer [A2]. The isocyanate content of prepolymer [A2] was 3.8%.

Production Example 3 Prepolymer [50 parts each of A and [A2]
of ethyl acetate to obtain prepolymer solutions [B1 and [B11].

Production Example 4 5 parts of terephthalyl chloride was dissolved in 100 parts of ethyl acetate to obtain a treatment liquid [C].

Example 1 - Production of composition 1 part of terephthalyl chloride was added to 100 parts of prepolymer [A 1] and thoroughly stirred and mixed to obtain composition [AI']. To 100 parts of prepolymer [A23], 1 part of phthalyl chloride was added and thoroughly stirred and mixed to obtain composition [A2'] - 50 parts each of compositions [A1'] and [A2']
It was dissolved in 0 parts of ethyl acetate to obtain composition solutions CB1''] and [B2'].

Example 2 Film strength measurement test Prepolymer [Aho], [A2] and composition [AI'
] and [A2'] were each flowed to a thickness of 1 mm on a Teflon plate set horizontally, and kept in a constant temperature and humidity chamber set at 20°C and relative humidity of 80°C for 7 days to form a moisture-curing sheet. I got it. The tensile properties of the sheet were measured based on JIS K2SO3 (vulcanized rubber physical testing method). The results are shown in Table 1, which shows that it is tough and flexible, and has physical properties suitable for use as a rubber coating.

Table-I Example 3 - Adhesion test A A-1. After degreasing the surfaces of natural rubber and chloroprene sheets with a thickness of 2-■ with acetone, 0.002 g/cm of treatment liquid [C] was applied to each with a brush. 2 coats were applied and air-dried at room temperature. Prepolymer solution [B11] was applied to each treated surface of natural rubber and chloroprene using a 4111L applicator, and after air-drying at room temperature, it was kept in a constant temperature and humidity chamber set at 20°C and 80% relative humidity for 7 days to cure. After that, hardened skin training 2
25 base meshes with an interval of m layers were made and a peel test was conducted using cellophane tape.

A-2, prepolymer solution [B1] replaced with [B11,
A similar test was conducted.

Example 4 - Adhesion test B B-1, after degreasing the surfaces of natural rubber and chloroprene sheets with a thickness of 2-1 with acetone, a composition solution [B1
'] was applied with a 4NIL applicator, air-dried at room temperature, kept in a constant temperature and humidity chamber set at 20°C and 60% relative humidity for 7 days, and then cured. Eyes 254I1 were prepared and a peel test was conducted using cellophane tape.

A similar test was conducted by replacing B-20 composition solution [B1'l with [B2'].

Comparative Example I Comparative Adhesion Test C C-1, Composition solution [BI'l was mixed with prepolymer solution [B
In place of Example 11, a test similar to Example 4 was conducted.

C-20 composition solution [B1'] and prepolymer solution [B
2], a similar test was conducted.

The test results of Example 3.4 and Comparative Example I are shown in Table-2 and Table-3.

Table-2 Examples note) Upper row; natural rubber, Lower tier; Chloroprene Table-3 Comparative example [Effect of the invention]

Claims (1)

[Claims] 1. (A) a terminal isocyanate urethane prepolymer made from a polyol and a stoichiometric excess of polyisocyanate, and (B) a general formula ▲ There are numerical formulas, chemical formulas, tables, etc. ▼ ( I ) ( A resin composition for a rubber coating comprising as an essential component a compound represented by the formula (wherein n is any one of 2, 3, and 4). 2. The composition according to claim 1, wherein the polyol is a polyether polyol. 3. The composition according to claim 1 or 2, wherein the isocyanate component of the terminal isocyanate urethane prepolymer is diphenylmethane-4,4'-diisocyanate. 4. The composition according to any one of claims 1 to 3, wherein (B) is terephthalyl chloride. 5. The weight ratio of component (A) and component (B) is 1:0.005
The composition according to any one of claims 1 to 4, wherein ˜:0.1.