JPH09208895A - Two-component solventless urethane resin coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-component solventless urethane resin coating material which exhibits a good smoothness when applied to an object. strongly adheres even to a plastic foam, and can fulfill the purpose of surface protection to the max. SOLUTION: This coating material comprises a polyisocyanate component, a polyol component, a cross-linker, and a catalyst. Higher than 50wt.% of the polyol component is a polyol or polyols having secondary hydroxyl groups. The cross-linker is diethyltoluenediamine. The catalyst is pref. a bismuth compd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-component solventless urethane-based resin coating material suitable for use for the purpose of surface protection of objects such as plastic foams, plastics moldings, metals and wood materials. It is a thing.

[0002]

2. Description of the Related Art The strength of a foam has been increased by forming a reinforcing film on the surface of the plastic foam. A urethane resin coating agent is suitable as the reinforcing film forming agent.

Japanese Examined Patent Publication (Kokoku) No. 3-67107
No. 147329), a main agent (diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate or a modified product thereof), a curing agent (mainly composed of a polymer polyol having a primary hydroxyl group), a cross-linking agent (polyamine). , Polyhydric alcohols or alkanolamines) and a catalyst (tertiary amine or organometallic compound) blended room temperature curing type high reaction polyurethane stock solution using a high pressure spraying device at 30-210 kg / c
A method of strengthening a foam protective body is shown, which is sprayed on the surface of the protective body with a discharge pressure of m ² .

Among the crosslinking agents, those specifically mentioned as polyamines are ethylenediamine, hexamethylenediamine, p-phenylenediamine, 3,3'-.
Dichloro-4,4'-diaminodiphenylmethane, 3,
3'-dimethyl-4,4'-diaminodiphenylmethane, 3,5,3 ', 5'-tetramethyl-4,4'-diaminodiphenylmethane, 3,5-diethyl-3',
5'-diisopropyldiaminodiphenylmethane, 3,
5,3 ′, 5′-tetraisopropyldiaminodiphenylmethane, which does not include polyamine as a cross-linking agent in Examples, but in Comparative Example 1, 4,4′-diamino-3,3 ′. -Using dichlorodiphenylmethane. Among the catalysts, those specifically referred to as an organometallic compound are lead octoate, lead naphthenate, tin octoate, and dibutyltin dilaurate,
An example using dibutyltin dilaurate is given in the examples.

Japanese Unexamined Patent Publication (Kokai) No. 7-179634 discloses a method of forming a reinforced coating of a polyurethane elastomer on the surface of a polystyrene foam, using a two-component reactive solventless urethane raw material as the polyurethane elastomer raw material, It is disclosed that the polystyrene foam surface is spray-applied and the maximum temperature of the polystyrene foam between the time of application and the completion of curing is in the range of 30 to 80 ° C.

This publication describes that bifunctional diamines and diols are used as the chain extender, and glycerin, sorbitol and the like are used as the crosslinking agent. The primary or secondary di- or polyamines have both functions of a chain extender and a cross-linking agent, and 3,3'dichloro-, which has heretofore been widely used as such.
There is also a description that 4,4'diaminodiphenylmethane can be used. The catalyst may be blended if necessary, but there is no further description. Examples include:
An example using MDI prepolymer as the polyisocyanate, polypropylene glycol as the polyol, and 1,4-butanediol as the chain extender is shown.

[0007]

[Problems to be Solved by the Invention] Japanese Patent Publication No. 3-67107
The method for strengthening the foamed protective body of the publication is actually adopted mainly for strengthening polystyrene foamed bodies such as fish boxes, and is considered to be effective in preventing dents and scratches,
There is still room for improvement in terms of smoothness that affects the finished appearance and adhesion to the foam, especially in terms of maintaining adhesion when impacted.

The method for forming a reinforced coating disclosed in Japanese Patent Application Laid-Open No. 7-179634 is intended to increase the adhesion to the foam by limiting the maximum temperature of the foam surface during the coating formation process. I am dissatisfied with this point and need further improvement.

Under such a background, the present invention has a good smoothness when applied to an object, has a large adhesive force even for an object such as a plastic foam, and maximizes the purpose of surface protection. It is an object of the present invention to provide a two-component solventless urethane-based resin coating material that can achieve the above.

[0010]

Means for Solving the Problems The two-component solventless urethane resin coating material of the present invention comprises a polyisocyanate component (A),
A two-component solventless urethane resin coating agent comprising a polyol component (B), a cross-linking agent (C) and a catalyst (D), wherein the amount of the polyol component (B) in excess of 50% by weight is secondary. It is characterized in that it is composed of an OH group-containing polyol and that the cross-linking agent (C) is diethyltoluenediamine. In this case, it is particularly preferable to use a bismuth compound as the catalyst (D).

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The two-component solventless urethane resin coating material of the present invention comprises a polyisocyanate component (A) and a polyol component (B).
The crosslinking agent (C) and the catalyst (D) are essential components.

<Polyisocyanate Component (A)> As the polyisocyanate component (A), various polyisocyanates used in the production of polyurethane can be used, but those mainly composed of diphenylmethane diisocyanate type polyisocyanate are particularly preferable. It is suitable.

Examples of the diphenylmethane diisocyanate type polyisocyanate include (1) diphenylmethane-4,4'-diisocyanate referred to as pure MDI, (2)
Polymethylene polyphenyl polyisocyanate referred to as crude MDI or polymeric MDI, (3) Dicyclohexylmethane-4,4′-diisocyanate referred to as hydrogenated MDI or H ₁₂ MDI, (4) Above (1) to
(3) Polyisocyanate and a modified product of one or more kinds of carbodiimide, isocyanurate, uretonimine, etc., (5) MDI polyisocyanate of (1) to (3) above, and biuret, alohanate, etc. A modified product of one or more kinds, (6) a prepolymer of the polyisocyanate of the above (1) to (3) and a hydroxypolyol (polyalkylene glycol, etc.) or a polyhydric alcohol,
(7) Polyisocyanates of the above (1) to (3), which are modified with carbodiimide, isocyanurate, uretonimine and the like and are prepolymerized with hydroxypolyol or polyhydric alcohol. Among these, (1), (4), (6) and (7), especially (4), (6) and (7) are important.

As polyisocyanates other than diphenylmethane diisocyanate type polyisocyanate,
2,4- or / and 2,6-tolylene diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, hexamethylene diisocyanate,
Isophorone diisocyanate, p-phenylene diisocyanate, transcyclohexane-1,4-diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, tetramethyl xylene diisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate -4-isocyanate Methyl octane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate and the like can be mentioned. However, even when these are used, a small proportion (50 wt% or less, usually 30 wt% or less, further 20 wt% or less) is used in combination with diphenylmethane diisocyanate-based polyisocyanate.
It is desirable to use

<Polyol component (B)> Polyol component
As (B), in the present invention, 50% by weight thereof
Of the secondary OH group-containing polyol (preferably 60% by weight or more, more preferably 70% by weight or more, especially 80% by weight or more, further 90% by weight or more). This is because the use of the secondary OH group-containing polyol is positive in terms of mechanical strength when applied to the surface of an object, adjustment of curing time, and realization of surface smoothness.

As the secondary OH group-containing polyol, polymer polyols and low-molecular polyols exemplified below are used, and polymer polyols are preferably used in a main proportion.

First, as the high molecular weight polyol, polypropylene glycol, polybutylene glycol, castor oil or a derivative thereof, a random or block copolymer of propylene oxide and butylene oxide, a random or propylene oxide end block of propylene oxide and ethylene oxide. Copolymer, random butylene oxide terminal block copolymer of butylene oxide and ethylene oxide, random or propylene oxide terminal copolymer of propylene oxide and tetrahydrofuran, random or butylene oxide terminal copolymer of butylene oxide and tetrahydrofuran Obtained by addition-polymerizing propylene oxide to a chain extender such as glycerin or trimethylolpropane Polymers obtained by addition polymerization of butylene oxide to chain extenders such as glycerin and trimethylolpropane, polymers obtained by addition polymerization of propylene oxide and butylene oxide to chain extenders such as glycerin and trimethylolpropane, as described below. Second-class O
Polymers obtained by addition-polymerizing propylene oxide to polyols other than H group-containing polyols, secondary O described below.
Examples thereof include polymers obtained by addition-polymerizing butylene oxide to polyols other than H group-containing polyols.

The low molecular weight polyols include propylene glycol, dipropylene glycol, tripropylene glycol, 2,4-pentanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,3. 2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-ethyl-1,3-hexanediol, glycerin, diglycerin, 1,2,6-hexanetriol,
Examples thereof include sorbitol, triisopropanolamine, phenyldiisopropanolamine, N, N'-bis (2-hydroxypropyl) aniline and the like.

As the polyol other than the secondary OH group-containing polyol in the polyol component (B), polymer polyols and low molecular weight polyols exemplified below are used.

First, as the polymer polyol, polyethylene glycol, polytetramethylene glycol, a copolymer of ethylene oxide and tetrahydrofuran, a polyester polyol such as a condensation type polyester polyol / lactone type polyester polyol / polycarbonate diol is used as a chain extender. Examples thereof include those using a polyol containing only primary OH groups and polybutadiene polyol.

The low molecular weight polyols include ethylene glycol, diethylene glycol, triethylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,4. -Bis (2'-
(Hydroxyethoxy) benzene, trimethylolpropane, pentaerythritol, diethanolamine, triethanolamine, phenyldiethanolamine, N,
Examples thereof include N'-di (2-hydroxyethyl) aniline.

The overall OH value of the polyol component (B) is 10 to
It is preferably in the range of 380 KOHmg / g, especially 20-350 KOHmg / g. This is because when the OH value is in such a range, the physical properties as a coating material are enhanced.

<Crosslinking Agent (C)> In the present invention, diethyltoluenediamine is used as the crosslinking agent (C). Diethyltoluenediamine is a compound represented by the following chemical formula 1.

[0025]

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Thus, in the present invention, diethyltoluenediamine is used as the cross-linking agent (C), and the intended purpose can be achieved by this, but an amount (for example, 30% by weight or less, which does not impair the gist of the present invention, (Especially less than 20% by weight)
If so, amines other than diethyltoluenediamine may be used in combination.

<Catalyst (D)> As the catalyst (D), it is particularly preferable to use a bismuth compound in the present invention.
Specific examples of bismuth compounds include bismuth acetate, bismuth oxalate, bismuth oleate, bismuth valerate, bismuth stannate, bismuth citrate, bismuth salicylate, bismuth-2-ethylhexanoate, bismuth neodecanoate, and the like. Organic acid salts, bismuth carbonate, bismuth hydrate,
Examples thereof include bismuth nitrate, bismuth oxide, and bismuth phosphate, and bismuth neodecanoate is particularly important. The bismuth compound is usually used in the form of a solution mixed with an appropriate amount of an organic acid (for example, neodecanoic acid) or the like in a liquid state or in a form of being dissolved in a polyol as a simple substance in order to make it into a liquid state.

As the catalyst (D), catalysts other than bismuth compounds such as tertiary amines, organic tin compounds and organic lead compounds can be used. However, since the effect of the bismuth-based compound is remarkably large as compared with the case where dibutyltin dilaurate is used, for example, the bismuth-based compound is used in an amount of 0.001 with respect to the entire polyol component (B) as described below even when other catalysts are used. It is preferable to use the catalyst in an amount of not less than 0.01% by weight (in particular, not less than 0.01% by weight), and to additionally use another catalyst.

<Other Compounds> The coating material of the present invention includes
In addition to the polyisocyanate component (A), the polyol component (B), the cross-linking agent (C) and the catalyst (D) described above, it is possible to add a chain extender (polyvalent amine etc.) that does not belong to the polyol component. it can. The chain extender belonging to the polyol component is classified as the above-mentioned polyol component (B) for convenience.

In addition, if necessary, a filler, a coloring agent,
A plasticizer, an oxidation stabilizer, an ultraviolet absorber, a flame retardant, an antistatic agent, a hydrolysis inhibitor, an antifungal agent, a dehydrating agent, an antifoaming agent and the like can be added.

<Coating Method> The two-component solventless urethane resin coating agent of the present invention comprises a polyisocyanate component (A)
Agent, polyol component (B) as agent B, crosslinker (C)
The catalyst (D) and the chain extender are usually blended on the side of the B agent.

The mixing ratio of the polyisocyanate component (A) and the polyol component (B) is such that the equivalent ratio of NCO / active H is
It is suitable to set 0.9 to 1.3, preferably 1.0 to 1.2. Active H means H that can react with an NCO group,
For example, H of OH group, H of NH ₂ group, H of COOH group
And so on.

The amount of the cross-linking agent (C) compounded is the polyol component.
(B) 1-40% by weight, preferably 5-30, relative to the whole
It is appropriate to set the content by weight%, and if the proportion is too small, the curing rate, smoothness, and adhesiveness will be unsatisfactory and the coating strength will tend to be lowered, while the proportion will be too large. In this case, the smoothness and the adhesiveness may be deteriorated.

Taking the case of a bismuth compound as an example, the blending amount of the catalyst (D) is based on the entire polyol component (B).
It is suitable to set 0.001 to 10% by weight, preferably 0.01 to 5% by weight, and when the ratio is too small, it becomes unsatisfactory in terms of curing rate, smoothness, adhesion and coating strength,
When the ratio is too large, the smoothness and the adhesiveness may be deteriorated.

The two-component solventless urethane type resin coating material of the present invention is used by mixing the liquids A and B immediately before use, or
The liquid and the liquid B are mixed and used at the tip of a two-headed gun, and applied to the surface of the object by a method such as coating, dipping or spraying to form a film. As a result, the surface of the object is protected. There is no particular limitation on the thickness of the coating, and any thickness from a thin film to a thick film can be used.

Examples of the object include plastic foam, plastic molded product, metal, wood material, cloth, concrete, inorganic board, and the like, and they are also applicable to semi-finished products such as shoe soles.

<Function> The smoothness of the film formed when the two-component solventless urethane-based resin coating material of the present invention is applied to an object is determined by the use of the diethyltoluenediamine used as the crosslinking agent (C) and the catalyst ( D) (particularly bismuth-based compound) is deeply involved, and if either one is omitted, shrinkage or unevenness may appear, or smoothness may be impaired. Even if diethyltoluenediamine is used as the cross-linking agent (C),
When a catalyst other than a bismuth-based compound is used as the catalyst (D), a crosslinking agent similar to that when a bismuth-based compound is used.
Since a synergistic effect with (C) cannot be achieved, it is particularly recommended to use a bismuth-based compound as the catalyst (D).

The combination of diethyltoluenediamine used as the cross-linking agent (C) and the catalyst (D) (particularly bismuth compound) is extremely advantageous in terms of adhesion to an object (particularly plastic foam). Act on. This is an anchor effect based on the appropriate cohesive action of the above-mentioned cross-linking agent (C),
This is probably because the curing rate with the catalyst (D) (particularly bismuth-based compound) cooperated.

By combining the components of the composition of the present invention together in appropriate amounts, the desired coating strength and hardness can be obtained, and the smoothness when applied to an object is good. Even an object such as a plastics foam has a high adhesion, and the object of surface protection can be maximally achieved.

[0040]

The present invention will be further described with reference to the following examples. Hereinafter, "parts" refers to parts by weight.

Example 1 <Liquid A> 61 parts of carbodiimide-modified diphenylmethane-4,4′-diisocyanate having a free NCO% of 29.0 was prepolymerized with 39 parts of polypropylene glycol having a molecular weight of 2000 at a temperature of 80 ° C. in a nitrogen stream. The reaction was carried out for 2.0 hours to obtain a prepolymer having a free NCO% of 16.4.
This was used as the polyisocyanate component (A).

<Liquid B> 62 parts and 3 parts of polypropylene glycol having a molecular weight of 2000 as the polyol component (B)
26 parts of functional modified polypropylene glycol, cross-linking agent
Liquid B was prepared by mixing 12 parts of diethyltoluenediamine as (C) and 1.0 part of a neodecanoic acid solution of bismuth neodecanoate as catalyst (D) (bismuth ratio was 16% by weight).

<Formation of coating> Using a spray device "QSP-26" manufactured by Nippon Synthetic Chemical Industry Co., Ltd., a mixture of the above liquids A and B (NCO) was applied to a flat plate made of polystyrene foam having an expansion ratio of 70 times. The equivalent ratio of / active H was 1.1) and the coating was formed.

The surface of this product was rich in impact resilience and was tough, and neither damage to the coating film due to external impact nor damage to the polystyrene foam was observed. This product had good surface smoothness and good adhesion.

Comparative Example 1 61 parts of polypropylene glycol having a molecular weight of 2000 as the polyol component (B) and 26 parts of trifunctional modified polypropylene glycol were added to 4,4 'as the crosslinking agent (C).
13 parts of diaminodiphenylmethane was dissolved by heating and added, and 1.0 part of a solution of bismuth neodecanoate as a catalyst (D) in neodecanoic acid (the proportion of bismuth was 16% by weight) was mixed to prepare a liquid B.

This solution B was mixed with the same solution A as in Example 1 (the equivalent ratio of NCO / active H was 1.1) and sprayed on the polystyrene foam in the same manner as in Example 1 to form a film.

The surface of this product was hard but brittle, and the coating was damaged by an external impact. Moreover, the surface smoothness of this product was inferior, and a concavo-convex pattern that appeared to be shrinkage of the resin appeared.

Comparative Example 2 69 parts of polypropylene glycol having a molecular weight of 2000 as the polyol component (B), 25 parts of trifunctional modified polypropylene glycol and 6 parts of 1,4-butanediol, and bismuth neodecano as the catalyst (D). 1.0 part of a neodecanoic acid solution of ate (the proportion of bismuth was 16% by weight) was mixed to prepare a solution B.

This solution B was mixed with the same solution A as in Example 1 (the equivalent ratio of NCO / active H was 1.1) and sprayed on the polystyrene foam in the same manner as in Example 1 to form a film.

The surface of this product was flexible, had tack residue, and lacked impact resilience, so it was deformed by an external impact. Further, the smoothness was poor due to foaming due to the delay in curing, and the adhesion was also poor.

Example 2 61 parts of carbodiimide-modified diphenylmethane-4,4'-diisocyanate having a free NCO% of 29.0 was mixed with a polyoxypropylene polyoxyethylene block copolymer having a molecular weight of 2400 at a temperature of 80 ° C. in a nitrogen stream (terminal poly (Oxyethylene) 39 parts was prepolymerized and reacted for 2.0 hours to obtain a prepolymer having a free NCO% of 16.4.
This was used as the polyisocyanate component (A).

This solution A was mixed with the same solution B as in Example 1 (NCO / active H equivalent ratio was 1.1), and sprayed on the polystyrene foam in the same manner as in Example 1 to form a film.

The surface of this product was rich in impact resilience and tough, and neither damage to the coating film due to external impact nor damage to the polystyrene foam was observed. This product had good surface smoothness and good adhesion.

Example 3 60 parts of carbodiimide-modified diphenylmethane-4,4'-diisocyanate having a free NCO% of 29.0 was prepolymerized with 40 parts of polypropylene glycol having a molecular weight of 3000 at a temperature of 80 ° C. in a nitrogen stream for 2.0 hours. The reaction was performed to obtain a prepolymer having a free NCO% of 16.5. This was used as the polyisocyanate component (A).

This solution A was mixed with the same solution B as in Example 1 (the equivalent ratio of NCO / active H was 1.1) and sprayed on the polystyrene foam in the same manner as in Example 1 to form a film.

The surface of this product was rich in impact resilience and tough, and neither damage to the coating film due to impact from the outside nor damage to the polystyrene foam was observed. This product had good surface smoothness and good adhesion.

Example 4 Spray device "QSP-" manufactured by Nippon Synthetic Chemical Industry Co., Ltd.
No. 26 ”, a mixture of liquid A and liquid B (NCO / active H equivalent ratio: 1.1) having the same composition as in Example 1 was sprayed onto an asbestos-cement pearlite plate having an expansion ratio of 70 to form a film. .

The surface of this product was rich in impact resilience and tough, and neither damage to the coating film due to external impact nor damage to the asbestos-cement pearlite plate was observed. This product had good surface smoothness and good adhesion.

<Various Test Results> In order to carry out a quantitative evaluation, the above coating agents of Examples 1 to 3 and Comparative Examples 1 to 3 were used to form a plate made of a polystyrene foam having an expansion ratio of 70 times as described above. The mixture of A liquid and B liquid (NCO / active H equivalent ratio: 1.1) was sprayed to form a film. Table 1 shows the hardness (JIS-A), DuPont impact test value, 60 ° specular gloss, and adhesion test results.

In Table 1, the DuPont impact test value is the hardness (500 g, notch tip diameter 1/2 inch) when an object is coated with a coating material with a thickness of 1 mm. Regarding the adhesion test, after coating the target material with a coating agent to a thickness of 1 mm, observe the surface of the adhesive part when the coating is peeled off, and a good (good) or ×
It was evaluated as (poor). In the column of the destroyed part at the time of peeling,
The “object” is material destruction of the object, and the “interface” is interface peeling.

[0061]

[Table 1] Implementation Example Comparative Example 1 2 3 1 2 Hardness 94 94 95 100 74 Dupont impact test value>1500>1500> 1500 <100 300 60 ° specular gloss 85 83 86 20 32 during the adhesion test evaluation ○ ○ ○ × × Peeling Destruction part of the object Object object Object object interface Interface ^# (with ^# tack remaining)

[0062]

EFFECTS OF THE INVENTION By using the two-component solventless urethane resin coating material of the present invention, not only the desired coating strength and hardness can be obtained, but also the smoothness when applied to an object is good and the plastics Even an object such as a foam has a high adhesion, and the object of surface protection can be achieved to the maximum extent.

Claims (4)

[Claims] 1. A two-component solventless urethane resin coating agent comprising a polyisocyanate component (A), a polyol component (B), a cross-linking agent (C) and a catalyst (D), wherein the polyol component (B) Of the secondary OH group-containing polyol, and the cross-linking agent (C) is diethyltoluenediamine. . 2. The two-component solventless urethane resin coating material according to claim 1, wherein the catalyst (D) is composed of a bismuth compound. 3. The two-component solventless urethane resin coating material according to claim 1, wherein the polyisocyanate component (A) is mainly composed of diphenylmethane diisocyanate polyisocyanate. 4. A coating agent for protecting the surface of an object.
The two-component solventless urethane resin coating material described.