JPH10130575A - Coating material for stripping concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating material for stripping concrete capable of manifesting an excellent stripping effect and water resisting properties by coating the coating material on the member to be brought into contact with the concrete by adding a metal catalyst to a polyphenylene polyisocyanate having a specific composition to be a specified concentration. SOLUTION: The coating material comprises (A) a polyphenylene polyisocyanate of formula I [(n) is 0 or a positive integer] with (B) an added metal catalyst of 0.5-500ppm in terms of the metal with the proviso that the component A includes 20-60wt.% diphenylmethanediisocyanate which is the one of formula I having the (n) of 0 and includes <=8wt.% diphenylmethane-2,4'- diisocyanate of formula II in the diphenylmethanediisocyanate. The component B is preferably a salt formed out of a metal having 1-3 valet electric charges and an organic aid or an organic chelate compound, e.g. cobalt naphthenate or lead octylate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane concrete release coating having excellent release effect and water resistance and excellent diversion divergence. More specifically, the present invention relates to a polyphenylene polyisocyanate (hereinafter abbreviated as polymeric MDI) which reacts with an active hydrogen component. N = 0) diphenylmethane diisocyanate (hereinafter abbreviated as MDI) contained in the component
Is 20 to 60% by weight, and the diphenylmethane-2,4'-diisocyanate (hereinafter referred to as 2,4'M
DI) is 8% by weight or less, and a metal catalyst is added in an amount of 0.5 to 500 ppm in terms of metal to improve the reactivity with active hydrogen.
And a paint for peeling concrete.

[0002]

2. Description of the Related Art Conventionally, as a release agent applied to a concrete form, a mineral oil, a saponified animal or vegetable oil or a saponified animal or vegetable oil, a metal soap of a higher fatty acid, a mineral oil in which paraffin or the like is dissolved, etc. Oil-based release agent, and a water-soluble release agent made into a self-emulsifying type by adding a surfactant to the oil-based release agent, etc., but in the case of oiliness, fire danger, pollution,
If there is a problem in the work environment, if water-soluble,
There is a drawback that the release agent flows out due to rainfall or the like, and a sufficient release effect cannot be obtained. In addition, both oily and water-soluble require re-application of a release agent every time the mold is released and diverted. Therefore, a method of applying a synthetic resin paint to solve the problem of re-application of the release agent has been considered,
The paint alone does not provide a sufficient peeling effect and a concrete finished surface. Therefore, a method of blending a specific high-boiling compound into a synthetic resin paint has been adopted. Polyurethane resins are used as coating resins from the viewpoint of durability. A wood plywood is usually used for the concrete formwork, and an application device such as a roll coater or a knife coater is used as an application method.

[0003] Polyurethane resin applied to wood plywood is
It is manufactured by reacting isocyanate and polyol having active hydrogen, polyamine, a mixture of polyol and polyamine, or water and the like. Generally, polymeric MDI is used as isocyanate of polyurethane resin for concrete peeling paint. .

[0004]

The reactivity between polymeric MDI and a compound containing active hydrogen has a great effect on the residence time of a portion in front of a coater and the curability after application when a paint is applied to wood plywood. If the reactivity is too fast, the curing proceeds in the area in front of the coater, gelling occurs, and eventually the coating becomes impossible. If the reactivity is too slow, the curing after application becomes insufficient, and when the products are stacked, a so-called blocking phenomenon occurs in which the plywoods adhere to each other. Therefore, the development of a coating resin that has a low initial gelation and a high curing speed after application has been desired.

Conventionally, methods for controlling the above-mentioned reactivity include a reaction temperature, such as a raw material temperature and a molding temperature, and a method of adding a catalyst. In fact, it is inevitable to use the method described above.
However, when a catalyst is added to polymeric MDI, there is a problem that the polymeric MDI itself is polymerized and gelled, or reacts with moisture in the air to deactivate NCO groups. It is added to the hydrogen compound side. However, when a catalyst is added to the active hydrogen compound side, the problem arises that the catalyst is deactivated due to hydrolysis by water in the active hydrogen compound.

As a method for solving these problems, a tertiary amine compound is known as a catalyst for promoting the formation of urethane bonds as a reaction control by adding a catalyst. There is a problem that the MDI itself polymerizes and gels. Further, even when the amount of addition is reduced to such an extent that gelation does not occur, there remain problems such as no effect on reactivity and generation of odor.

As another method of controlling the reaction, JP-A-7-25977 discloses a polyisocyanate composition obtained by adding a cyclic carbonate compound and / or an alkyl carbonate compound and an alkali metal salt to polymeric MDI. Although a method for producing a rigid polyurethane foam using the same is described, in this method, when a carbonate compound is used in combination with a metal salt, a part thereof is decomposed by reaction heat and carbon dioxide gas is generated, so that a foaming agent is used. Practical problems have arisen, such as the necessity of adjusting the formulation such as the amount.

On the other hand, JP-A-7-80820 discloses that
A polyurethane-based concrete release coating characterized in that the gelling time at 10 ° C. is adjusted within 10 minutes is disclosed. The adjustment method is performed by adding a catalyst, heating an active hydrogen compound component, and an isocyanate component. However, there is no clear description on the addition method of the catalyst and the like. ], The catalyst is added to the active hydrogen compound side. As described above, the addition of a catalyst to the active hydrogen compound has a disadvantage that the catalyst is deactivated by hydrolysis or the like of water in the active hydrogen compound, and there is a problem that heating further promotes deactivation. . Further, there is no specific description about 2,4′MDI.

[0009] Japanese Patent Publication No. 3-76381 discloses a method in which an isocyanate compound and an active hydrogen compound are mixed with each other in accordance with JIS.
A method for producing a urethane resin-coated concrete form wood board using a fast-curing urethane resin liquid having a gel time of 30 minutes or less and a non-adhesive plastic film in accordance with the gel time measurement method specified in K-6840. It has been disclosed. However, there is no description about the adjustment of the gel time, and only the addition of the catalyst to the active hydrogen compound is described in [Examples]. However, in this method, a plastic film must be used, and there is a problem that the workability is poor and the work is substantially troublesome.

Japanese Patent Publication No. 7-2931 discloses that the average number of isocyanate groups is 2.7 or more and the viscosity is 400 mPa · s.
There is a concrete release paint using an organic polyisocyanate of / 25 ° C. or higher, and only the addition of a catalyst to an active hydrogen compound is described in [Examples], but this cannot control the reactivity. There are problems such as.

Japanese Patent Publication No. 5-59944 discloses a polyurethane-based concrete mold comprising, as an essential component, a mixed polyol of polymeric MDI and an amine polyol alone or a polyoxyalkylene polyol, and having a gelling time adjusted within 10 minutes. There is a description relating to a release coating, and in [Means for Solving the Problems] in [Detailed Description of the Invention], it is described that the catalyst should be preliminarily mixed with the polyol component, and [Example] Although only the addition of a catalyst to an active hydrogen compound is described, it still falls within the category of a conventional method by reaction control, and has not yet solved the above-mentioned problems, and it is completely insufficient. I have to say. Therefore, it has been desired to develop more stable catalyst types and addition methods that do not react with the raw materials and do not deactivate the catalyst itself.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above problems, and as a result, have found that Polymeric M
The MDI contained in the DI component is 20 to 60% by weight, the 2,4′MDI in the MDI has a composition of 8% by weight or less, and the metal catalyst is 0.5 to 500% in terms of metal.
It has been found that when ppm is added, the reactivity with a compound having active hydrogen can be improved without deactivating the NCO group, thereby completing the present invention. According to the method of the present invention, it is possible to use the compound in a conventional compound formulation without changing the compound formulation. Further, the method of the present invention
The content of 2,4′MDI in DI is reduced, and the addition of a catalyst to the isocyanate side is also used. The catalyst is not deactivated, the storage stability is good, and the initial gelation is reduced. It is characterized by being slow and fast after application.

That is, the present invention is as follows (1) to (4). (1) Paint the surface of the member in contact with concrete,
It is a paint for improving the separation from concrete,
The polyisocyanate is a polyisocyanate in which a metal catalyst is added to the polyphenylene polyisocyanate represented by the general formula (1) [formula 3] in an amount of 0.5 to 500 ppm in terms of metal, and the polyphenylene polyisocyanate has the general formula ( 1) 20 to 60% by weight of diphenylmethane diisocyanate of n = 0 contained in 1), and 8% by weight of diphenylmethane-2,4'-diisocyanate represented by the formula (2) in the diphenylmethane diisocyanate. A concrete peeling paint characterized by using the following.

Embedded image (In the formula, n represents 0 or a positive integer.)

Embedded image (2) The concrete peeling paint according to (1), wherein the metal catalyst is a salt composed of a metal having 1 to 3 charges and an organic acid or an organic chelate compound. (3) The metal catalyst is a metal consisting of lead, zinc, tin, iron, cobalt, bismuth, copper, manganese, calcium, potassium, sodium, zirconium, magnesium, lithium or nickel, and naphthenic acid, octylic acid, neodecanoic acid, etc. The concrete peeling paint according to (2), which is a salt comprising an organic chelate compound such as a fatty acid or acetylacetone. (4) The metal catalyst is cobalt naphthenate, cobalt octylate, lead naphthenate, lead octylate, lead neodecanoate, zinc naphthenate, zinc octylate, tin naphthenate,
The concrete peeling paint according to (3), which is tin octylate, dibutyltin dilaurate, dibutyltin dioctate, iron naphthenate, iron octylate, copper naphthenate, bismuth neodecanoate or iron acetylacetone.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The polymeric MDI represented by the following general formula (1) used in the present invention has an MDI of 20 to 60.
% By weight and contained in MDI of the following formula (2)
The 2,4′MDI represented by the following formula is not more than 8% by weight. If the MDI content in the polymeric MDI exceeds 60% by weight, storage stability problems such as MDI precipitation occur. On the other hand, if it is less than 20% by weight, the viscosity of the polymeric MDI increases, and the workability deteriorates. Therefore, the MDI content in the polymeric MDI is preferably 20 to 60% by weight, more preferably 25 to 55% by weight.
% By weight is good. On the other hand, when the content of 2,4′MDI in the MDI exceeds 8% by weight, the reactivity becomes slow, which adversely affects the curability. Therefore, 2,4'MD in MDI
I is preferably 8% by weight or less, more preferably 5% by weight or less.

Embedded image (In the formula, n represents 0 or a positive integer.)

Embedded image

Specific examples of the metal catalyst used in the present invention include, for example, cobalt naphthenate, cobalt octylate, lead naphthenate, lead octylate, lead neodecanoate, manganese naphthenate, manganese octylate, naphthenate Zinc acid, zinc octylate, calcium naphthenate, calcium octylate, tin naphthenate, tin octylate, dibutyltin dilaurate, dibutyltin dioctate,
Potassium naphthenate, potassium octylate, zirconium naphthenate, zirconium octylate, iron naphthenate, iron octylate, magnesium naphthenate, lithium naphthenate, copper naphthenate, nickel octylate, bismuth neodecanoate, acetylacetone aluminum, acetylacetone chromium, Acetylacetone cobalt, acetylacetone copper, acetylacetone iron, acetylacetone nickel, acetylacetone vanadyl, acetylacetone zinc, acetylacetone indium, acetylacetone calcium, acetylacetone magnesium, acetylacetone manganese, acetylacetone yttrium, acetylacetone cerium, acetylacetone strontium, acetylacetonepalladium, acetylacetonebarium, a Tylacetone molybdenyl, acetylacetone lanthanum, acetylacetone zirconium, acetylacetone tin, acetylacetone titanium, and more preferably cobalt naphthenate, cobalt octylate, lead naphthenate, lead octylate, lead neodecanoate, zinc naphthenate, zinc octylate , Tin naphthenate, tin octylate, dibutyltin dilaurate, dibutyltin dioctate, iron naphthenate, iron octylate, copper naphthenate, bismuth neodecanoate, and iron acetylacetone are preferred. The metal catalyst is used in an amount of 0.5 to 500 ppm in terms of metal with respect to polymeric MDI. 500
If the amount exceeds ppm, the polymeric MDI itself polymerizes and gels, or reacts with moisture in the air, etc.
The problem of deactivation of the CO group occurs. When the amount is less than 0.5 ppm, the effect of the catalyst is small, and there is no difference in reactivity as compared with the case where no catalyst is used. Therefore, Polymeric MD
The amount of the metal catalyst used for I is 0.5 to 500 in metal conversion.
ppm is better, and more preferably 1 to 200 ppm. The metal catalyst may be directly added to the catalyst itself.However, since the amount of addition is very small, phthalate esters such as dimethyl phthalate, dibutyl phthalate and dioctyl phthalate, dioctyl adipate, diisobutyl adipate,
Diluted in dibasic acid esters such as diisodecyl adipate, phosphates such as tricresyl phosphate, chlorinated paraffins, plasticizers such as polyoxypropylene and polyoxyethylene, and organic solvents such as toluene, xylene and mineral spirits You may add it.

[0016]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. Parts in Examples are parts by weight unless otherwise specified. The raw materials used in the examples are as follows. Table 1 shows the composition of the polymeric MDI.

As the curing agent which is an active hydrogen compound, polypropylene ether glycol (Mitsui Toatsu Chemical Co., Ltd.)
A mixture of 84 parts / 11 parts / 5 parts by weight of dioctyl phthalate (manufactured by Kyowa Yuka Co., Ltd .: DOP) / calcium carbonate (whiten B manufactured by Shiraishi Calcium Co., Ltd.) was used. Reactivity measurement method 25 parts of polymeric MDI adjusted to 25 ° C.
After adding 100 parts of a curing agent whose temperature was adjusted to ° C and mixing and stirring, the arrival time up to 100,000 cps was measured with a B-type viscometer B8M (manufactured by Tokyo Keiki Co., Ltd.).

Example 1 Cobalt naphthenate (Naptex Co8%, manufactured by Nippon Chemical Industry Co., Ltd .: 8%) was added to 70 parts of polymeric MDI (Cosmonate M-23, manufactured by Mitsui Toatsu Chemicals, Inc.) in terms of metal.
0 ppm was added and mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 2, the time to reach 100,000 cps was short and good.

Example 2 70 parts of polymeric MDI (Cosmonate M-24, manufactured by Mitsui Toatsu Chemicals Co., Ltd.) was added with 20 ppm in terms of metal of cobalt octylate (Nikka Chemical Industries, Ltd., Nikka Octix Co, 12%). Was added and mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 2, the time to reach 100,000 cps was short and good.

Example 3 Lead of naphthenate (Naptex Pb 24%, manufactured by Nippon Kagaku Sangyo Co., Ltd.) was added to 70 parts of polymeric MDI (Cosmonate M-23, manufactured by Mitsui Toatsu Chemicals, Inc.) at 1 p in terms of metal.
pm was added and mixed and stirred. The resulting polymeric MD
I had good storage stability without deactivating the NCO group. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 2, 100,000 cp was obtained.
The s arrival time was short and good.

Example 4 70 parts of polymeric MDI (Cosmonate M-23, manufactured by Mitsui Toatsu Chemicals, Inc.) were converted to lead octylate (Nikka Octix Pb, 17% DOP) in terms of metal in terms of metal. 1 ppm was added and mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 2, the time to reach 100,000 cps was short and good.

Example 5 To 70 parts of polymeric MDI (Cosmonate M-24, manufactured by Mitsui Toatsu Chemicals, Inc.) was added 1 ppm of lead neodecanoate (Minico P-30, manufactured by Active Materials Chemical Co., Ltd.) in terms of metal. And mixed and stirred. The resulting polymeric MDI is NC
The storage stability was good without deactivation of the O group.
As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 2, the time to reach 100,000 cps was short and good.

Example 6 Zinc naphthenate (Naphtex Zn8%, manufactured by Nippon Kagaku Sangyo Co., Ltd .: 8% Naphtex Zn) was added to 70 parts of polymeric MDI (Cosmonate M-23, manufactured by Mitsui Toatsu Chemicals, Inc.) at 10 p in terms of metal.
pm was added and mixed and stirred. The resulting polymeric MD
I had good storage stability without deactivating the NCO group. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 2, 100,000 cp was obtained.
The s arrival time was short and good.

Example 7 Zinc octylate (Nikka Chemical Industries, Ltd .: Nikka Octix Zn 8%) was added to 70 parts of polymeric MDI (Cosmonate M-23, manufactured by Mitsui Toatsu Chemicals, Inc.) at 10 ppm in terms of metal. Was added and mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. Polymeric MDI obtained in this way
The results of the measurement of the reactivity of
The time to reach 10,000 cps was short and good.

Example 8 70 parts of polymeric MDI (manufactured by Mitsui Toatsu Chemicals, Inc .: Cosmonate M-24) were mixed with 20 ppm of tin octylate (manufactured by Nippon Kagaku Sangyo Co., Ltd .: Nikka Octix Sn 14%) in terms of metal. Was added and mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. Polymeric MD obtained in this way
As a result of measuring the reactivity of I, as shown in Table-2, 1
The time to reach 100,000 cps was short and good.

Example 9 Dibutyltin dilaurate (Neostan U-100, manufactured by Nitto Kasei Corporation) was added to 70 parts of polymeric MDI (Cosmonate M-23, manufactured by Mitsui Toatsu Chemicals, Inc.) in an amount of 20 ppm in terms of metal. Was mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. Polymeric MDI obtained in this way
The results of the measurement of the reactivity of
The time to reach 10,000 cps was short and good.

Example 10 Dibutyltin dioctate (manufactured by Nippon Chemical Industry Co., Ltd .: di-butyl Sn di-octate) was used in 70 parts of polymeric MDI (manufactured by Mitsui Toatsu Chemicals Co., Ltd .: Cosmonate M-23).
Was added in an amount of 20 ppm in terms of metal, followed by mixing and stirring. The resulting polymeric MDI is free of NCO group inactivation,
The storage stability was good. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 2, the time to reach 100,000 cps was short and good.

Example 11 70 parts of Polymeric MDI (Cosmonate M-23, manufactured by Mitsui Toatsu Chemicals, Inc.) were mixed with 20 p in metal conversion of iron naphthenate (Naphtex Fe5%, manufactured by Nippon Chemical Industry Co., Ltd.).
pm was added and mixed and stirred. The resulting polymeric MD
I had good storage stability without deactivating the NCO group. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 2, 100,000 cp was obtained.
The s arrival time was short and good.

Example 12 70 parts of polymeric MDI (manufactured by Mitsui Toatsu Chemicals Co., Ltd .: Cosmonate M-24) was mixed with 30 ppm of metal in terms of metal by adding iron octylate (Nikka Kagaku Sangyo Co., Ltd .: Nikka Octix Fe6%). Was added and mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. Polymeric MDI obtained in this way
The results of the measurement of the reactivity of
The time to reach 10,000 cps was short and good.

Example 13 Copper naphthenate (Naphtex Cu5%, manufactured by Nippon Kagaku Sangyo Co., Ltd., 5%) was added to 70 parts of polymeric MDI (Cosmonate M-24, manufactured by Mitsui Toatsu Chemicals, Inc.) at a metal conversion of 500 parts.
ppm was added and mixed and stirred. Polymeric M obtained
DI had good storage stability without deactivating the NCO group. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 2, 100,000 c
The ps arrival time was short and good.

Example 14 Bismuth neodecanoate (Cas) was added to 70 parts of polymeric MDI (Cosmonate M-24, manufactured by Mitsui Toatsu Chemicals, Inc.).
Chem .: COSCAT # 83) in terms of metal.
5 ppm was added and mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 2, the time to reach 100,000 cps was short and good.

Example 15 In 70 parts of polymeric MDI (manufactured by Mitsui Toatsu Chemicals Co., Ltd .: Cosmonate M-24), iron acetylacetone (manufactured by Nippon Kagaku Sangyo Co., Ltd .: ferric Nasem) was dissolved in toluene.
0.5 ppm in terms of metal was added and mixed and stirred. The resulting polymeric MDI is free of NCO group inactivation,
The storage stability was good. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 2, the time to reach 100,000 cps was short and good.

Comparative Example 1 Reactivity was measured without adding a catalyst to 70 parts of Polymeric MDI (manufactured by Mitsui Toatsu Chemicals, Inc .: Cosmonate M-1500). The result was 100,000 cp as shown in Table-3.
The arrival time was long.

Comparative Example 2 Copper naphthenate (Naphtex Cu5%, manufactured by Nippon Kagaku Sangyo Co., Ltd .: 5%) was added to 70 parts of polymeric MDI (Cosmonate M-25, manufactured by Mitsui Toatsu Chemicals, Inc.) in an amount of 0.4% in terms of metal.
ppm was added and mixed and stirred. Polymeric M obtained
DI had good storage stability without deactivating the NCO group. However, Polymeric M obtained in this way
The results of measuring the reactivity of DI were as shown in Table-3,
The time to reach 100,000 cps was long, and no effect was observed.

Comparative Example 3 70 parts of polymeric MDI (Cosmonate M-1500, manufactured by Mitsui Toatsu Chemicals Co., Ltd.) were converted to lead octylate (Nikka Octix Pb 17% DOP) by metal conversion in terms of metal. 600 ppm was added and mixed and stirred. The results of measuring the reactivity of the obtained polymeric MDI are shown in Table-
As shown in Fig. 3, the time to reach 100,000 cps was short,
Gelation was observed, and there was a problem in storage stability.

Comparative Example 4 Diazabicyclo [2,2,2] was added to 70 parts of polymeric MDI (Cosmonate M-23 manufactured by Mitsui Toatsu Chemicals, Inc.).
Octane (Kaolyzer No. 30 manufactured by Kao Corporation) was added in an amount of 500 ppm, followed by mixing and stirring. As a result of measuring the reactivity of the obtained polymeric MDI, as shown in Table 3, although the time to reach 100,000 cps was short, gelation was observed, and a problem was observed in storage stability.

Comparative Example 5 Cobalt naphthenate (Naphtex Co 8%, manufactured by Nippon Chemical Industry Co., Ltd., 8%) was added to 70 parts of polymeric MDI (Cosmonate M-1500, manufactured by Mitsui Toatsu Chemicals, Inc.) in an amount of 20 ppm in terms of metal. Was mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. Polymeric MD obtained in this way
As a result of measuring the reactivity of I, as shown in Table-3, 1
Although the time to reach 100,000 cps was short, it was longer than that in Example 1.

Comparative Example 6 Cobalt octylate (Nikka Kagaku Co., Ltd .: Nikka Octix Co 12%) was added to 70 parts of polymeric MDI (Cosmonate M-25 manufactured by Mitsui Toatsu Chemicals, Inc.) at 20 ppm in terms of metal. Was added and mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 3, the time to reach 100,000 cps was short, but it was longer than that of Example 2.

Comparative Example 7 Lead octylate (Nikka Octic Pb 17% DOP) was converted to metal in 70 parts of polymeric MDI (Cosmonate M-1500, manufactured by Mitsui Toatsu Chemicals, Inc.) in terms of metal. 1 ppm was added and mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 3, the time to reach 100,000 cps was short, but it was longer than that of Example 4.

Comparative Example 8 To 70 parts of polymeric MDI (Cosmonate M-25, manufactured by Mitsui Toatsu Chemicals, Inc.), 1 ppm of lead neodecanoate (Minico P-30, manufactured by Active Materials Chemical Co., Ltd.) was added in terms of metal. And mixed and stirred. The resulting polymeric MDI is NC
The storage stability was good without deactivation of the O group.
As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 3, the time to reach 100,000 cps was short, but it was longer than that of Example 5.

Comparative Example 9 Zinc octylate (Nikka Chemical Industries, Ltd .: Nikka Octix Zn 8%) was added to 70 parts of Polymeric MDI (Cosmonate M-1500, manufactured by Mitsui Toatsu Chemicals, Inc.) at 10 ppm in terms of metal. Was added and mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. Polymeric M obtained in this way
The results of measuring the reactivity of DI were as shown in Table-3,
Although the time to reach 100,000 cps was short, it was longer than that of Example 7.

Comparative Example 10 Tin octylate (Nikka Chemical Industries, Ltd .: Nikka Octix Sn 14%) was added to 70 parts of Polymeric MDI (Cosmonate M-25, manufactured by Mitsui Toatsu Chemicals, Inc.) at 20 ppm in terms of metal. Was added and mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. Polymeric MD obtained in this way
As a result of measuring the reactivity of I, as shown in Table-3, 1
Although the time to reach 100,000 cps was short, it was longer than that of Example 8.

Comparative Example 11 Polymeric MDI (Cosmonate M-1500, manufactured by Mitsui Toatsu Chemicals, Inc.) was mixed with 70 parts of dibutyltin dioctate (manufactured by Nippon Kagaku Sangyo Co., Ltd., di-butyl Sn di-octate) as a metal. 20 ppm in terms of conversion was added and mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 3, the time to reach 100,000 cps was short, but it was longer than that of Example 10.

Comparative Example 12 Copper naphthenate (Naphtex Cu5%, manufactured by Nippon Kagaku Sangyo Co., Ltd., 5%) was added to 70 parts of polymeric MDI (Cosmonate M-25, manufactured by Mitsui Toatsu Chemicals, Inc.) in terms of metal.
ppm was added and mixed and stirred. Polymeric M obtained
DI had good storage stability without deactivating the NCO group. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 3, 100,000 c
The ps arrival time was short, but longer than in Example 13.

Comparative Example 13 Bismuth neodecanoate (Cas) was added to 70 parts of polymeric MDI (Cosmonate M-25 manufactured by Mitsui Toatsu Chemicals, Inc.).
Chem .: COSCAT # 83) in terms of metal.
5 ppm was added and mixed and stirred. The obtained polymeric MDI had good storage stability without deactivation of NCO groups. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 3, the time to reach 100,000 cps was short, but it was longer than that of Example 14.

Comparative Example 14 Ferrous acetylacetone (Nercem ferric iron, manufactured by Nippon Kagaku Sangyo) was dissolved in toluene in 70 parts of polymeric MDI (manufactured by Mitsui Toatsu Chemicals, Cosmonate M-25).
0.5 ppm in terms of metal was added and mixed and stirred. The resulting polymeric MDI is free of NCO group inactivation,
The storage stability was good. As a result of measuring the reactivity of the thus obtained polymeric MDI, as shown in Table 3, although the time to reach 100,000 cps was short, Example 1 was performed.
It was longer than 5

[0047]

[Table 1] Table 1 ──────────────────────────────────── Polymeric MDI NCO% Viscosity cps / 25 ℃ MDI 2,4'MDI Content a) Content b) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━コ ス Cosmonate M-23 31.0 477 31.6 3.0────────────────────────────────── {Cosmonate M-24 31.4 191 42.0 7.3} {Cosmonate M-1500 30.5 1,040 24.4 9.5} ────── Cosmonate M-25 31.0 470 31.6 ──────────────────────────────────── Note: a) MDI content in polymeric MDI (% By weight) b) Content of 2,4 ′ MDI in polymeric MDI (% by weight)

[0048]

[Table 2] Table 2 Polymeric catalyst Catalyst amount Storage 100,000 cps MDI stability arrival time ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example 1 M-23 Cobalt naphthenate 20 Good 3'45 "Example 2 M-24 Cobalt Octylate 20 Good 4'15" Example 3 M-23 Lead Naphthenate 1 Good 2'55 "Example 4 M-23 Lead Octylate 1 Good 2'30 "Example 5 M-24 Lead neodecanoate 1 Good 2'55" Example 6 M-23 Zinc naphthenate 10 Good 3'45 "Example 7 M-23 Zinc octylate 10 Good 3'05" Example 8 M -24 Tin octylate 20 Good 3'05 "Example 9 M-23 Diperlaurate 20 Good 3'10 "Example 10 M-23 Dibutyltin dioctate 20 Good 2'45" Example 11 M-23 Iron naphthenate 20 Good 4'00 "Example 12 M-24 Iron octylate 30 Good 3 '50 "Example 13 M-24 copper naphthenate 500 good 4'00" Example 14 M-24 bismuth neotecanoate 0.5 good 3'20 "Example 15 M-24 iron acetylacetone 0.5 good 4'00 ────────────────────────────────────

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[Table 3] Table 3 ポ リ Polymeric catalyst Catalyst amount Storage 100,000 cps MDI stability arrival time ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Comparative Example 1 M-1500 6'00 "Comparative Example 2 M-25 Copper naphthenate 0.4 Good 6'05" Comparative Example 3 M-1500 Lead octylate 600 Gelation 2'10 "Comparative Example 4 M-23 Peadicyclo [2,2,2] octane 500 Gelation 3'30 "Comparative Example 5 M-1500 Cobalt naphthenate 20 Good 4'15" Comparative Example 6 M-25 Cobalt octylate 20 Good 4'30 "Comparative Example 7 M-1500 Lead octylate 1 Good 3'00 "Comparative Example 8 M-25 Lead Neodecanoate 1 Good 3'10" Comparative Example 9 -1500 Zinc octylate 10 Good 3'35 "Comparative Example 10 M-25 Tin octylate 20 Good 3'20" Comparative Example 11 M-1500 Siftiltine dioctate 20 Good 3'15 "Comparative Example 12 Copper 500 good 4'15 "Comparative Example 13 M-25 bismuth neotecanoic acid 0.5 good 3'35" Comparative Example 14 M-25 iron acetylacetone 0.5 good 4'15 " ──────────────────────────

[0050]

According to the present invention, in a paint for coating the surface of a member in contact with concrete to improve the peeling from concrete, the MDI contained in the polymeric MDI component is 20 to 60% by weight. Storage stability without deactivating NCO groups by using polymeric MDI in which 2,4′MDI in MDI is 8% by weight or less and a metal catalyst is added in an amount of 0.5 to 500 ppm in terms of metal. In a favorable state, the reactivity with the active hydrogen compound could be improved, and the productivity of the concrete peeling paint could be improved. Further, since it can be used as it is without changing the conventional formulation, there is no effect on productivity and on-site workability. Further, the paint using the specific MDI of the present invention has a slow initial gelation,
Since curing after application is fast, there is no gelation just before the coater, and no blocking phenomenon occurs between products after application.

Claims (4)

[Claims] 1. A paint for coating a surface of a member in contact with concrete to improve peeling from concrete, wherein the polyisocyanate is a polyphenylene polyisocyanate represented by the general formula (1): Is a polyisocyanate to which a metal catalyst is added in an amount of 0.5 to 500 ppm in terms of metal, and the polyphenylene polyisocyanate contains 20 to 60% by weight of n = 0 diphenylmethane diisocyanate contained in the general formula (1). ,
A paint for stripping concrete, wherein the diphenylmethane diisocyanate contains 8% by weight or less of diphenylmethane-2,4'-diisocyanate represented by the formula (2) [formula 2]. Embedded image (In the formula, n represents 0 or a positive integer.) 2. The concrete peeling paint according to claim 1, wherein the metal catalyst is a salt comprising a metal having 1 to 3 charges and an organic acid or an organic chelate compound. 3. The method according to claim 1, wherein the metal catalyst is lead, zinc, tin, iron, cobalt, bismuth, copper, manganese, calcium, potassium,
Sodium, zirconium, magnesium, metal consisting of lithium or nickel, naphthenic acid, octylic acid,
3. The concrete peeling paint according to claim 2, which is a salt comprising a fatty acid such as neodecanoic acid or an organic chelate compound such as acetylacetone. 4. The method according to claim 1, wherein the metal catalyst is cobalt naphthenate, cobalt octylate, lead naphthenate, lead octylate, neodecanoate, zinc naphthenate, zinc octylate, tin naphthenate, tin octylate, dibutyltin dilaurate, dibutyltin diamine. 4. The concrete peeling paint according to claim 3, wherein the paint is octate, iron naphthenate, iron octylate, copper naphthenate, bismuth neodecanoate or iron acetylacetone.