JP3993653B2 - Two-component solventless urethane resin coating agent - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a two-component solventless urethane-based resin coating suitable for use for the purpose of protecting the surface of an object such as plastic foam, plastic molding, metal or wood material.
[0002]
[Prior art]
  The strength of the foam is increased by forming a reinforced film on the surface of the plastic foam. A suitable reinforcing film forming agent is a urethane-based resin coating agent.
[0003]
  Japanese Examined Patent Publication No. 3-67107 (JP-A-60-147329) includes a main agent (diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate or a modified product thereof), a curing agent (containing 50% or more of primary hydroxyl groups). And containing 50% or more of a polymer polyol having an OH value of 100 mgKOH / g or less), a crosslinking agent (polyamines, polyhydric alcohols or alkanolamines), catalyst (tertiary amine or organometallic compound) There is shown a method for strengthening a foamed protective body in which a room temperature curable highly reactive polyurethane stock solution containing is sprayed onto the surface of the protective body at a discharge pressure of 30 to 210 kg / cm @ 2 using a high pressure spraying apparatus.
[0004]
  Here, 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, Although 3 ′, 5′-tetraisopropyldiaminodiphenylmethane is not mentioned in the examples, polyamine is used as a crosslinking agent. In Comparative Example 1, 4,4′-diamino-3,3′-dichloro Diphenylmethane is used. Among the catalysts, those specifically mentioned as organometallic compounds are lead octoate, lead naphthenate, tin octoate, and dibutyltin dilaurate, and examples include examples using dibutyltin dilaurate. Yes.
[0005]
  In JP-A-7-179634, in a method of forming a reinforced film made of a polyurethane elastomer on a polystyrene foam surface, a two-component reactive solvent-free urethane raw material is used as the polyurethane elastomer raw material, and the urethane raw material is used as the polystyrene foam surface. And the maximum temperature of the polystyrene foam from the point of application to the completion of curing is disclosed in the range of 30-80 ° C.
[0006]
  This publication states that bifunctional diamines and diols are used for the chain extender, and glycerin, sorbitol, etc. are used for the crosslinking agent. Primary, secondary di- or polyamines have the functions of both chain extenders and crosslinkers, and use 3,3'dichloro-4,4'diaminodiphenylmethane, which has been widely used as such. There is also a description that it is possible. About a catalyst, although there may be mix | blending as needed, there is no description further. In the examples, MDI prepolymer is used as the polyisocyanate, polypropylene glycol is used as the polyol, and 1,4-butanediol is used as the chain extender.
[0007]
[Problems to be solved by the invention]
  The method for reinforcing a foam protector disclosed in Japanese Patent Publication No. 3-67107 is actually used mainly for strengthening polystyrene foam such as a fish box, and seems to be effective in preventing dents and scratches. However, there is still room for improvement, particularly in terms of maintaining adhesion, such as smoothness that affects the finished appearance and adhesion to the foam, at the time of impact.
[0008]
  The method for forming a reinforced film disclosed in Japanese Patent Application Laid-Open No. 7-179634 is intended to increase the adhesion to the foam mainly by limiting the maximum temperature of the foam surface in the process of forming the film, but is not satisfactory in terms of the resin composition. There is a need for further improvement.
[0009]
  Under such a background, the present invention has good smoothness when applied to an object, and even an object such as a plastic foam has a high adhesion and achieves the purpose of surface protection to the maximum. It is an object of the present invention to provide a two-component solventless urethane resin coating agent that can be used.
[0010]
[Means for Solving the Problems]
  The two-component solventless urethane resin coating agent of the present invention is
  A two-component solventless urethane resin coating comprising a polyisocyanate component (A), a polyol component (B), a crosslinking agent (C) and a catalyst (D),
  The polyisocyanate component (A) Is mainly composed of diphenylmethane diisocyanate polyisocyanate,
  An amount exceeding 50% by weight of the polyol component (B) is composed of a primary OH group-containing polyol.Being
  The primary OH group-containing polyol is 6: 4 to 9: 1 in a weight ratio of a high OH number polyol having an OH number X exceeding 100 and a low OH number polyol having an OH number smaller than X above. A mixture of
  The crosslinking agent (C) is made of diethyltoluenediamine.,
  The catalyst (D) Consists of bismuth organic acid salt, and
  A coating for protecting the surface of an object,
Characterized byIt is.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
  The present invention will be described in detail below.
[0012]
  The two-component solventless urethane resin coating agent of the present invention comprises a polyisocyanate component (A), a polyol component (B), a crosslinking agent (C) and a catalyst (D) as essential components.
[0013]
<Polyisocyanate component (A)>
  Polyisocyanate component (A)as,Those mainly composed of diphenylmethane diisocyanate polyisocyanateUsed.
[0014]
  Here, examples of diphenylmethane diisocyanate polyisocyanates are:
  (1) Diphenylmethane-4,4'-diisocyanate called pure MDI,
  (2) polymethylene polyphenyl polyisocyanate called crude MDI or polymeric MDI,
  (3) Hydrogenated MDI or H₁₂Dicyclohexylmethane-4,4'-diisocyanate, referred to as MDI,
  (4) a modified product of the polyisocyanate of (1) to (3) above and one or more of carbodiimide, isocyanurate, uretonimine,
  (5) A modified product of the MDI polyisocyanate of (1) to (3) above and one or more of biuret, allophanate, etc.
  (6) A prepolymer of the polyisocyanate of (1) to (3) above with a hydroxy polyol (polyalkylene glycol or the like) or a polyhydric alcohol,
  (7) The polyisocyanate of the above (1) to (3) is modified with carbodiimide, isocyanurate, uretonimine, etc. and prepolymerized with a hydroxy polyol or a polyhydric alcohol,
Etc. Among these, (1), (4), (6) and (7), particularly (4), (6) and (7) are important.
[0015]
  Polyisocyanates other than diphenylmethane diisocyanate polyisocyanate include 2,4- or / and 2,6-tolylene diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, trans Cyclohexane-1,4-diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, tetramethylxylene diisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyl octane, 1, 3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, etc. . However, even when these are used, it is desirable to use a small amount (50% by weight or less, usually 30% by weight or less, and further 20% by weight or less) in combination with diphenylmethane diisocyanate polyisocyanate.
[0016]
<Polyol component (B)>
  As the polyol component (B), in the present invention, the amount exceeding 50% by weight (preferably 60% by weight or more, more preferably 70% by weight or more, especially 80% by weight or more) is the primary OH group-containing polyol. It is made up of. The use of a primary OH group-containing polyol is positive in terms of appropriate strength and flexibility (elongation, etc.) of the coating when applied to the surface of an object, adjustment of curing time, and realization of surface smoothness. is there.
[0017]
  The above primary OH group-containing polyol has a weight ratio of 6: 4 to 9 in a weight ratio of a high OH polyol having an OH value X exceeding 100 and a low OH polyol having an OH value smaller than X above. 1 mixtureis necessary.This is because in such a range, a flexible and tough film can be obtained. The OH value X is preferably 110 or more, more preferably 115 or more. The upper limit of the OH value X is practically about 140.
[0018]
  The OH group-containing polyol includes a primary OH group-containing polyol and a secondary OH group-containing polyol.
[0019]
  Among the polyol components (B), as the primary OH group-containing polyol, polymer polyols and low molecular polyols as exemplified below are used, and it is preferable to use the polymer polyol in a main ratio.
[0020]
  First, as a polymer polyol, polyethylene glycol, polytetramethylene glycol, a copolymer of ethylene oxide and tetrahydrofuran, a polyester polyol such as a condensed polyester polyol / lactone polyester polyol / polycarbonate diol, etc. Examples include those using polyols containing only OH groups, polybutadiene polyols, and the like. Moreover, what capped the secondary OH group of polypropylene glycol or polybutylene glycol with ethylene oxide (that is, ethylene oxide terminal block copolymer) can also be used suitably.
[0021]
  Low molecular 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, N′-di (2-hydroxyethyl) aniline and the like.
[0022]
  As the secondary OH group-containing polyol, high molecular polyols and low molecular polyols as exemplified below are used.
[0023]
  First, as the polymer 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 copolymer of propylene oxide and ethylene oxide Random or butylene oxide end block copolymer of butylene oxide and ethylene oxide, random or propylene oxide end copolymer of propylene oxide and tetrahydrofuran, random or butylene oxide end copolymer of butylene oxide and tetrahydrofuran, glycerin or Glycerin, a polymer obtained by addition polymerization of propylene oxide to a chain extender such as trimethylolpropane A polymer obtained by addition polymerization of butylene oxide to a chain extender such as trimethylolpropane, a polymer obtained by addition polymerization of propylene oxide or butylene oxide to a chain extender such as glycerin or trimethylolpropane, Examples thereof include a polymer obtained by addition polymerization of propylene oxide to a primary OH group-containing polyol, and a polymer obtained by addition polymerization of butylene oxide to the aforementioned primary OH group-containing polyol.
[0024]
  Low molecular polyols include propylene glycol, dipropylene glycol, tripropylene glycol, 2,4-pentanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, and 1,2-cyclohexane. Diol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-ethyl-1,3-hexanediol, glycerin, diglycerin, 1,2,6-hexanetriol, sorbitol, triisopropanolamine, phenyl diisopropanol Examples thereof include amines and N, N′-bis (2-hydroxypropyl) aniline.
[0025]
  The total OH value of the polyol component (B) is preferably in the range of 10 to 380 KOHmg / g, particularly 20 to 350 KOHmg / g. This is because the physical properties as a coating agent are increased when the OH value is in such a range.
[0026]
<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.
[0027]
[Chemical 1]
[0028]
  Thus, in the present invention, diethyltoluenediamine is used as the crosslinking agent (C), whereby the intended purpose can be achieved. However, the amount does not detract from the gist of the present invention (for example, 30% by weight or less, especially 20% (% By weight or less), an amine other than diethyltoluenediamine may be used in combination.
[0029]
<Catalyst (D)>
  As the catalyst (D), in the present invention,Bismuth organic acid salt is used. Bismuth organic acid saltSpecific examples of bismuth acetate, bismuth oxalate, bismuth oleate, bismuth valerate, bismustannate, bismuth citrate, bismuth salicylate, bismuth-2-ethylhexanoate, bismuth neodecanoate, etc.And especiallyBismuth neodecanoate is important.Bismuth organic acid saltIn order to make it liquid, it 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, or dissolved in a polyol in a single state.
[0030]
  As catalyst (D),Bismuth organic acid saltOther catalysts, for exampleBismuth compounds other than bismuth organic acid salts (bismuth carbonate, bismuth hydrate, bismuth nitrate, bismuth oxide, bismuth phosphate, etc.)Tertiary amines, organic tin compounds, organic lead compounds, and the like can also be used. However,Bismuth organic acid saltThe effect of is significantly greater than when dibutyltin dilaurate is used, for example.Bismuth organic acid saltAs described later, it is preferable to use 0.001% by weight or more (particularly 0.01% by weight or more) of the polyol component (B) as a whole, and to use another catalyst in combination with it.
[0031]
<Other compounds>
  In addition to the polyisocyanate component (A), polyol component (B), cross-linking agent (C) and catalyst (D) described above, the coating agent of the present invention includes a chain extender (polyvalent) which does not belong to the polyol component. Amine) and the like. The chain extender belonging to the polyol component is classified as the above-mentioned polyol component (B) for convenience.
[0032]
  In addition, a filler, a colorant, 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, etc. may be added as necessary. Can do.
[0033]
<Coating method>
  The two-component solventless urethane resin coating agent of the present invention uses a polyisocyanate component (A) as an agent A and a polyol component (B) as an agent B, a crosslinking agent (C), a catalyst (D), a chain extender Is usually added to the B agent side.
[0034]
  The blending ratio of the polyisocyanate component (A) and the polyol component (B) is suitably adjusted so that the equivalent ratio of NCO / active H is 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 an OH group, NH₂ Group H, COOH group H and the like.
[0035]
  The amount of the crosslinking agent (C) is 1 to 40% by weight, preferably 5 to 30% by weight, based on the whole polyol component (B). When the proportion is too small, the curing rate In addition, it is unsatisfactory in terms of smoothness and adhesion, and also tends to cause a decrease in coating strength. On the other hand, when the ratio is too large, there is a risk of a decrease in smoothness and adhesion.
[0036]
  Catalyst (D)Among them, the amount of bismuth organic acid salt isIt is appropriate that the content of the polyol component (B) is 0.001 to 10% by weight, preferably 0.01 to 5% by weight. When the ratio is too small, the curing rate, smoothness, adhesion, and coating strength are reduced. If the ratio is unsatisfactory and the ratio is too large, the smoothness and adhesion may be reduced.
[0037]
  The two-component solventless urethane resin coating agent of the present invention is used by mixing the A liquid and the B liquid immediately before use, or by mixing the A liquid and the B liquid at the tip of two head guns. The film is applied to the surface of an object by a method such as dipping or spraying. Thereby, the surface protection of the object is achieved. There is no particular limitation on the thickness of the coating, and any thickness can be selected from a thin film to a thick film.
[0038]
  Examples of the object include plastic foam, plastic molding, metal, wood material, cloth, concrete, and inorganic board, and can also be applied to semi-finished products such as shoe soles.
[0039]
<Action>
  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 diethyltoluenediamine used as the crosslinking agent (C) and the catalyst (D).Bismuth organic acid salt used asIs deeply involved, and if one of them is missing, shrinkage and unevenness appear, and smoothnessDamagedThere is a risk that. Even if diethyltoluenediamine is used as the crosslinking agent (C), the catalyst (D)Bismuth organic acid saltWhen using a catalyst other thanBismuth organic acid saltSynergistic effect with the crosslinking agent (C) is achievedI can't.
[0040]
  Diethyltoluenediamine used as crosslinking agent (C) and catalyst (D)Bismuth organic acid salt used asThe combination with the above also works extremely advantageously in terms of adhesion to an object (particularly plastic foam). This is because the anchor effect based on the moderate agglomeration by the cross-linking agent (C) and the catalyst (D)Bismuth organic acid salt used asThis is thought to be due to the cooperation of the curing rate due to.
[0041]
  And by combining the proper amount of each component constituting the composition of the present invention, the desired film strength and flexibility (elongation, etc.) can be obtained, and smoothness when applied to an object is good. Thus, even an object such as a plastic foam has an increased adhesion, and the object of surface protection can be achieved to the maximum extent.
[0042]
【Example】
  The following examples further illustrate the invention. Hereinafter, “parts” means parts by weight.
[0043]
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 and reacted for 2.0 hours to give a free NCO% A prepolymer of 16.4 was obtained. This was used as the polyisocyanate component (A).
[0044]
<Liquid B>
  As a polyol component (B), 67 parts of a primary OH group-containing polyol (polymer polyol) having a molecular weight of 900 and an OH value of 125 mgKOH / g obtained by addition polymerization of ethylene oxide to polypropylene glycol, 14 parts of a primary OH group-containing polyol (polymer polyol) having a molecular weight of 4000 and an OH value of 28 mg KOH / g obtained by addition polymerization of ethylene oxide and 1,4-butanediol (low molecular weight that also serves as a chain extender) Polyol) 6 parts of mixture, 13 parts of diethyltoluenediamine as crosslinker (C), and 1.0 part of neodecanoic acid solution of bismuth neodecanoate as catalyst (D) (bismuth ratio is 16% by weight) And liquid B was obtained.
[0045]
<Formation of film>
  Using a spray device “QSP-26” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., a mixture of the above-mentioned liquid A and liquid B (the equivalent ratio of NCO / active H is 1.1) on a flat plate made of polystyrene foam having an expansion ratio of 70 times. ) Was sprayed to form a film. Similarly, a film was formed on a polypropylene plate.
[0046]
  The surface of this fully cured material has moderate flexibility, rich impact resilience, toughness, damage to the coating due to external impact, and damage to the foam even in the case of foam. There wasn't. The surface smoothness of the coating surface was good and the appearance was favorable. Also, the adhesion was good. For example, in the peel test between the film and the foam, cohesive failure of the foam occurred.
[0047]
Comparative Example 1
  When Example 1 was repeated except that the catalyst (D) was not blended, the curing of the film was not sufficiently promoted, resulting in creaming.
[0048]
Comparative Example 2
  Example 1 was repeated except that 13 parts of 4,4'-diaminodiphenylmethane was used as the crosslinking agent (C) instead of 13 parts of diethyltoluenediamine.
[0049]
  This liquid B was mixed with the same liquid A as in Example 1 (NCO / active H equivalent ratio was 1.1), and sprayed onto a polypropylene plate in the same manner as in Example 1 to form a film.
[0050]
  However, the surface of this fully cured product had irregularities and lacked smoothness, and the appearance was poor. Also, the adhesion was poor, and interface peeling occurred in the peeling test.
[0051]
Reference example 1
  49 parts of a polypropylene glycol (secondary OH group-containing polyol, polymer polyol) having a molecular weight of 1000 as the polyol component (B), 32 parts and 1 part of a polypropylene glycol having a molecular weight of 4000 (secondary OH group-containing polyol, polymer polyol) , 4-Butanediol 6 parts (low molecular polyol used as chain extender), 13 parts of diethyltoluenediamine as cross-linking agent (C), and neodecanoic acid solution of bismuth neodecanoate as catalyst (D) (The ratio of bismuth is 16% by weight) 1.0 part was mixed to prepare a liquid B.
[0052]
  This liquid B was mixed with the same liquid A as in Example 1 (NCO / active H equivalent ratio was 1.1), and sprayed onto a polypropylene plate in the same manner as in Example 1 to form a film. The results are shown in Table 1 below.
[0053]
  Although the surface of this fully cured product was good, it was poor in flexibility and hard compared to that of Example 1. Further, as shown in Table 1, the hardness was larger and the elongation was smaller than that of Example 1. Therefore, when flexibility is required, the example 1 is preferable to the reference example 1.
[0054]
Reference example 2
  As a polyol component (B), 33 parts of polypropylene glycol (secondary OH group-containing polyol, polymer polyol) with a molecular weight of 1000, 48 parts of polypropylene glycol (secondary OH group-containing polyol, polymer polyol) with a molecular weight of 2000 and 1 part , 4-Butanediol 6 parts (low molecular polyol used as chain extender), 13 parts of diethyltoluenediamine as cross-linking agent (C), and neodecanoic acid solution of bismuth neodecanoate as catalyst (D) (The ratio of bismuth is 16% by weight) 1.0 part was mixed to prepare a liquid B.
[0055]
  This liquid B was mixed with the same liquid A as in Example 1 (NCO / active H equivalent ratio was 1.1), and sprayed onto a polypropylene plate in the same manner as in Example 1 to form a film. The results are shown in Table 1 below.
[0056]
  Although the surface of this fully cured product was good, it was poor in flexibility and hard compared to that of Example 1. Further, as shown in Table 1, the hardness was larger and the elongation was smaller than that of Example 1. Therefore, when flexibility is required, the example 1 is preferable to the reference example 2.
[0057]
Example 2
  61 parts of carbodiimide-modified diphenylmethane-4,4′-diisocyanate having a free NCO% of 29.0 is 39 parts of a polyoxypropylene polyoxyethylene block copolymer (terminal polyoxyethylene) having a molecular weight of 2400 at a temperature of 80 ° C. in a nitrogen stream. Prepolymerization was performed and the reaction was performed for 2.0 hours to obtain a prepolymer having a free NCO% of 16.4. This was used as the polyisocyanate component (A).
[0058]
  This solution A was mixed with the same solution B as in Example 1 (NCO / active H equivalent ratio was 1.1), and sprayed onto the polystyrene foam in the same manner as in Example 1 to form a film.
[0059]
  The surface of this fully cured material has moderate flexibility, rich impact resilience, toughness, damage to the coating due to external impact, and damage to the foam even in the case of foam. There wasn't. The surface smoothness of the coating surface was good and the appearance was favorable. Also, the adhesion was good. For example, in the peel test between the film and the foam, cohesive failure of the foam occurred.
[0060]
Example 3
  60 parts of carbodiimide-modified diphenylmethane-4,4′-diisocyanate with a free NCO% of 29.0 is prepolymerized with 40 parts of polypropylene glycol having a molecular weight of 3000 at a temperature of 80 ° C. in a nitrogen stream and reacted for 2.0 hours to give a free NCO% A prepolymer of 16.5 was obtained. This was used as the polyisocyanate component (A).
[0061]
  This solution A was mixed with the same solution B as in Example 1 (NCO / active H equivalent ratio was 1.1), and sprayed onto the polystyrene foam in the same manner as in Example 1 to form a film.
[0062]
  The surface of this fully cured material has moderate flexibility, rich impact resilience, toughness, damage to the coating due to external impact, and damage to the foam even in the case of foam. There wasn't. The surface smoothness of the coating surface was good and the appearance was favorable. Also, the adhesion was good. For example, in the peel test between the film and the foam, cohesive failure of the foam occurred.
[0063]
<Various test results>
  In order to make a quantitative evaluation, the above Examples 1-3,Comparative Example 2Using the coating agents of Reference Examples 1 and 2, the polypropylene plate was sprayed with the mixture of the liquid A and liquid B (equivalent ratio of NCO / active H was 1.1) to form a film. Moreover, after spraying to a polystyrene foam flat plate having a foaming ratio of 70 times in the same manner and sufficiently curing, the appearance of the film and the adhesion between the film and the foam are examined, and evaluated as ○ (good) or × (bad). did. Table 1 shows the test results of hardness (JIS-A), tensile strength, tensile elongation, and tear strength at this time. Comparative Example 1 is not listed in Table 1 because the curing of the film did not sufficiently promote and creamed.
[0064]
[Table 1]
  
                        Example  Comparative example  Reference example
  1 2 3 2 1 2
  Hardness (JIS-A) 80 85 80 98 90 97
  Tensile strength (kgf / cm²) 120 110 120 210 130 180
  Tensile elongation (%) 560 600 570 100 320 200
  Tear strength (kgf / cm²) 40 40 35 30 40 45
  Appearance ○ ○ ○ × ○ ○
  Adhesion ○ ○ ○ × ○ ○
[0065]
Example 4
  As the polyol component (B), 57 parts of a primary OH group-containing polyol (polymer polyol) having a molecular weight of 900 and an OH value of 125 mgKOH / g obtained by addition polymerization of ethylene oxide to polypropylene glycol, 24 parts of a primary OH group-containing polyol (polymer polyol) having a molecular weight of 1670 and an OH value of 67 mg KOH / g obtained by addition polymerization of ethylene oxide and 1,4-butanediol (a low molecular weight that also serves as a chain extender) Polyol) 6 parts of mixture, 13 parts of diethyltoluenediamine as crosslinker (C), and 1.0 part of neodecanoic acid solution of bismuth neodecanoate as catalyst (D) (bismuth ratio is 16% by weight) And liquid B was obtained.
[0066]
  This liquid B was mixed with the same liquid A as in Example 1 (NCO / active H equivalent ratio was 1.1), and sprayed onto a polypropylene plate in the same manner as in Example 1 to form a film. The surface of this fully cured material has moderate flexibility, rich impact resilience, toughness, damage to the coating due to external impact, and damage to the foam even in the case of foam. There wasn't. The surface smoothness of the coating surface was good and the appearance was favorable. Also, the adhesion was good. For example, in the peel test between the film and the foam, cohesive failure of the foam occurred.
[0067]
  In the same evaluation as in Table 1, the hardness (JISI-A) is 83 and the tensile strength is 125 kgf / cm.² , Tensile elongation is 580%, tear strength is 38kgf / cm² The appearance was ○ and the adhesion was ○.
[0068]
【The invention's effect】
  By using the two-component solventless urethane resin coating agent of the present invention, the desired film strength and flexibility (elongation, etc.) can be obtained, and smoothness when applied to an object is good. Even an object such as a foam has a high adhesion, and the object of surface protection can be achieved to the maximum.

Claims (2)

A two-component solventless urethane resin coating comprising a polyisocyanate component (A), a polyol component (B), a crosslinking agent (C) and a catalyst (D),
The polyisocyanate component (A) is mainly composed of diphenylmethane diisocyanate polyisocyanate,
The amount exceeding 50% by weight of the polyol component (B) is composed of a primary OH group-containing polyol ,
The primary OH group-containing polyol is 6: 4 to 9: 1 in a weight ratio of a high OH number polyol having an OH number X exceeding 100 and a low OH number polyol having an OH number smaller than X above. A mixture of
The crosslinking agent (C) comprises diethyltoluenediamine ;
The catalyst (D) comprises a bismuth organic acid salt; and
A coating for protecting the surface of an object,
A two-component solvent-free urethane resin coating characterized by The two-component solventless urethane resin coating agent according to claim 1 , wherein the OH value X is 110 or more.