JP2019001914A - Resin composition, coating and hot-melt adhesive - Google Patents

Abstract

To provide a resin composition that resists foaming when cured, and has excellent adhesiveness, and a coating and a hot-melt adhesive prepared with the resin composition.SOLUTION: A resin composition has a urethane prepolymer having an isocyanate group, and a carbon dioxide adsorbent.SELECTED DRAWING: None

Description

  The present invention relates to a resin composition, a paint, and a hot melt adhesive.

  A resin composition using a urethane prepolymer having an isocyanate group as a reactive resin can be cured by moisture and can be used without a solvent, and therefore has a low burden on the environment and the human body and is highly convenient. The use of such a resin composition as a paint for coating various substrates, a hot melt adhesive for bonding adherends, and the like has been studied.

  A reactive hot melt adhesive mainly composed of a urethane prepolymer exhibits a certain degree of adhesive strength in a short time due to cooling and solidification of the adhesive itself after being bonded to the adherend. Thereafter, the isocyanate group of the urethane prepolymer is reacted with moisture in the air or on the surface of the adherend to increase the molecular weight and to cause crosslinking, thereby forming an adhesive layer and exhibiting heat resistance. The adhesive layer can exhibit good adhesion even when heated. For example, Patent Documents 1 to 4 disclose reactive hot melt adhesive compositions containing a urethane prepolymer.

  A moisture-curing coating material containing a urethane prepolymer can form a uniform coating film on the construction surface. For example, Patent Documents 5 and 6 disclose paints containing a urethane prepolymer.

Japanese Patent Laid-Open No. 06-122860 JP-A 64-0554089 Japanese Patent Laid-Open No. 52-037936 International Publication No. 2016/157614 Japanese Patent Laid-Open No. 02-212571 JP 2001-342339 A

  When the isocyanate group of the urethane prepolymer is cured by reacting with moisture on the surface of the adherend or in the air, the isocyanate group reacts with water molecules to be converted to an amino group, and carbon dioxide is generated as a leaving group. For this reason, when the paint containing the urethane prepolymer is cured, carbon dioxide is generated to cause foaming, which may deteriorate the adhesion performance to the construction surface.

  The moisture-curable reactive hot melt adhesive generates carbon dioxide because it is cured by reacting with moisture in the air or on the surface of the adherend. Also, depending on the surrounding environment or the composition of the hot melt adhesive, bubbles may be generated inside the adhesive, and an adhesive that reduces foaming during curing is also required.

  An object of the present invention is to provide a resin composition having excellent adhesiveness in which foaming at the time of curing is suppressed, a coating material using the resin composition, and a hot melt adhesive.

  The present invention provides a resin composition comprising a urethane prepolymer having an isocyanate group and a carbon dioxide adsorbent.

  The carbon dioxide adsorbent may contain at least one selected from the group consisting of zeolite, activated carbon, and cerium oxide. The carbon dioxide adsorbent may contain cerium oxide.

  The resin composition may include 1 to 60 parts by mass of a carbon dioxide adsorbent with respect to 100 parts by mass of the urethane prepolymer.

  The resin composition of the present invention may be moisture curable.

  The present invention also provides a paint and a hot melt adhesive containing the resin composition.

  ADVANTAGE OF THE INVENTION According to this invention, the foaming at the time of hardening can be suppressed, and the coating material and hot-melt-adhesive using the resin composition which has the outstanding adhesiveness, and this resin composition can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

<Definition>
In the present specification, numerical ranges indicated using “to” indicate ranges including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value of a numerical range in a certain step may be replaced with the upper limit value or the lower limit value of a numerical range in another step. In the numerical range described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples. “A or B” only needs to include either A or B, and may include both. In the present specification, the content of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition. means.

[Resin composition]
The resin composition of this embodiment contains a urethane prepolymer having an isocyanate group and a carbon dioxide adsorbent. The resin composition of the present embodiment is preferably a moisture curable type.

(Urethane prepolymer)
The urethane prepolymer having an isocyanate group according to the present embodiment (hereinafter sometimes referred to as “urethane prepolymer”) is obtained by reacting a polyol component with an isocyanate component, and having an isocyanate group at the terminal of the urethane prepolymer. doing. Thereby, the outstanding adhesiveness can be exhibited after hardening.

  The urethane prepolymer has a structural unit derived from a polyol component and a structural unit derived from an isocyanate component.

  As a polyol component, it is more preferable to contain polyester polyol, polyether polyol, or polybutadiene polyol, and it is still more preferable to contain polyester polyol and polyether polyol from a viewpoint of improving adhesiveness more. The urethane prepolymer may be a reaction product of a polyol component containing a polyester polyol and a polyether polyol and an isocyanate component.

  When the urethane prepolymer has a structural unit derived from a polyester polyol, the solidification time and the viscosity can be adjusted. As the polyester polyol, a compound produced by a polycondensation reaction between a polyhydric alcohol and a polycarboxylic acid can be used. The polyester polyol has, for example, a polyhydric alcohol having 2 to 15 carbon atoms and 2 or 3 hydroxyl groups, and 2 to 14 carbon atoms (including carbon atoms in the carboxyl group), It may be a polycondensate with a polycarboxylic acid having 6 carboxyl groups.

  The polyester polyol may be a linear polyester diol produced from a diol and a dicarboxylic acid, or a branched polyester triol produced from a triol and a dicarboxylic acid. Branched polyester triols can also be obtained by reaction of diols with tricarboxylic acids.

  Examples of polyhydric alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol isomers, pentanediol isomers, hexanediol isomers, 2,2- Dimethyl-1,3-propanediol, 2-methylpropanediol, 2,4,4-trimethyl-1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,4-cyclohexane Examples thereof include aliphatic or alicyclic diols such as diol and 1,4-cyclohexanedimethanol; aromatic diols such as 4,4′-dihydroxydiphenylpropane, bisphenol A, bisphenol F, pyrocatechol, resorcinol, and hydroquinone. A polyhydric alcohol may be used individually by 1 type, and may be used in combination of 2 or more type. Among these, aliphatic diols are preferable, and aliphatic diols having 2 to 6 carbon atoms are more preferable.

  Examples of the polycarboxylic acid include aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, 1,2,4-benzenetricarboxylic acid; maleic acid, fumaric acid, aconitic acid, 1,2,3-propane. Aliphatic acids such as tricarboxylic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, cyclohexane-1,2-dicarboxylic acid, 1,4-cyclohexanediene-1,2-dicarboxylic acid Or alicyclic polycarboxylic acid is mentioned. A polycarboxylic acid may be used individually by 1 type, and may be used in combination of 2 or more type.

  In place of the polycarboxylic acid, a polycarboxylic acid derivative such as a carboxylic acid anhydride or a compound in which a part of the carboxyl group is esterified can also be used. Examples of the polycarboxylic acid derivative include dodecyl maleic acid and octadecenyl maleic acid.

  Examples of the polyester polyol include a crystalline polyester polyol and an amorphous polyester polyol. Judgment of crystallinity and non-crystallinity is judged in the state at 25 ° C. In the present specification, a polyester polyol that is crystalline at 25 ° C. is referred to as a crystalline polyester polyol, and a polyester polyol that is amorphous at 25 ° C. is referred to as an amorphous polyester polyol.

  The number average molecular weight (Mn) of the crystalline polyester polyol is preferably 500 to 10,000, more preferably 800 to 9000, and still more preferably 1000 to 8000, from the viewpoint of waterproofness and adhesiveness.

In this specification, the number average molecular weight is a value measured by gel permeation chromatography (GPC) and converted to standard polystyrene. The measurement of GPC can be performed under the following conditions.
Column: “Gelpack GLA130-S”, “Gelpack GLA150-S” and “Gelpack GLA160-S” (manufactured by Hitachi Chemical Co., Ltd., packed column for HPLC)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min Column temperature: 40 ° C
Detector: RI

  Examples of the amorphous polyester polyol include an amorphous polyester polyol having a molecular weight of 3000 or less and an amorphous polyester polyol having a molecular weight of 5000 or more. The Mn of the amorphous polyester polyol having a molecular weight of 3000 or less is preferably from 500 to 3000, more preferably from 1000 to 3000, from the viewpoint of further improving the adhesiveness of the resin composition. The Mn of the amorphous polyester polyol having a molecular weight of 5000 or more is preferably 5000 to 9000, more preferably 7000 to 8000, from the viewpoint of improving impact resistance.

  A polyester polyol may be used individually by 1 type, and may be used in combination of 2 or more type. The content of the polyester polyol is preferably 60 to 95 parts by mass, more preferably 60 to 90 parts by mass, based on 100 parts by mass of the total amount of polyol components, from the viewpoint of further improving the adhesiveness. More preferably, it is -85 mass parts.

  Since the urethane prepolymer has structural units derived from polyether polyol, it becomes possible to adjust the appropriate melt viscosity and open time after application of the resin composition, and has excellent workability, adhesiveness, waterproofness and flexibility. Can be granted. Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetramethylene glycol, and ethylene oxide-modified polypropylene glycol.

  The Mn of the polyether polyol is preferably 500 to 5000, more preferably 700 to 4500, and still more preferably 1000 to 4000, from the viewpoint of an appropriate open time after application and adhesiveness. A polyether polyol may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the polyether polyol is preferably 5 to 40 parts by mass based on 100 parts by mass of the total amount of polyol components from the viewpoint of easy adjustment to low viscosity and the viewpoint of adhesion to the substrate. More preferably, it is a mass part, and it is still more preferable that it is 15-25 mass part.

  The polyol component may contain polyols other than polyester polyols and polyether polyols. As the polyol, for example, polybutadiene polyol may be used.

  As the isocyanate component according to the present embodiment, diisocyanate is preferably used. Examples of the diisocyanate include aromatic isocyanates such as diphenylmethane diisocyanate, dimethyldiphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and p-phenylene diisocyanate; alicyclic isocyanates such as dicyclohexylmethane diisocyanate and isophorone diisocyanate; fats such as hexamethylene diisocyanate. Group isocyanate. The isocyanate component preferably contains an aromatic diisocyanate and more preferably contains diphenylmethane diisocyanate from the viewpoints of reactivity and adhesiveness. An isocyanate component may be used individually by 1 type, and may be used in combination of 2 or more type.

  The method for producing the urethane prepolymer is not particularly limited. The urethane prepolymer may be produced, for example, by mixing a polyol with an isocyanate, or by mixing a mixture of a polyester polyol and an isocyanate, a mixture of a polyether polyol and an isocyanate, and a mixture of a polybutadiene polyol and an isocyanate. Also good.

  When the urethane prepolymer is synthesized, the mixing ratio of the isocyanate component and the polyol component is such that the ratio of isocyanate group (NCO) equivalent of the isocyanate component / hydroxyl group (OH) equivalent of the polyol component is 1.5 to 3 NCO / OH. 0.0 is preferable, and 1.8 to 2.5 is more preferable. When the NCO / OH ratio is 1.5 or more, the resulting urethane prepolymer is prevented from increasing in viscosity, and workability is easily improved. When the NCO / OH ratio is 3.0 or less, foaming hardly occurs during the moisture curing reaction of the resin composition, and there is a tendency to suppress a decrease in adhesiveness.

(Carbon dioxide adsorbent)
The adsorbent according to the present embodiment is not particularly limited as long as it can adsorb carbon dioxide. The carbon dioxide adsorbent may contain at least one selected from the group consisting of zeolite, activated carbon and cerium oxide.

  The zeolite is not particularly limited, and a commercially available synthetic zeolite adsorbent may be used. Examples of commercially available synthetic zeolite include “Mizuka Sieves” manufactured by Mizusawa Chemical Industry Co., Ltd., “HSZ” manufactured by Tosoh Corporation. The activated carbon is not particularly limited, and commercially available activated carbon may be used. Examples of commercially available activated carbon include Kuraray Co., Ltd. manufactured by Kuraray Co., Ltd.

  The carbon dioxide adsorbent preferably contains cerium oxide. Since cerium oxide is excellent in carbon dioxide adsorptivity, it is possible to further suppress foaming due to carbon dioxide generated in the resin during moisture curing of the resin composition.

  The cerium oxide is not particularly limited, and a commercially available product may be used as it is, or cerium oxide produced by the following method may be used. The cerium oxide may be produced, for example, by firing cerium carbonate or cerium oxalate, or may be produced by mixing ammonium hydrogen carbonate and a cerium nitrate aqueous solution. Cerium oxide may be used alone or in combination of two or more.

  The average particle diameter of cerium oxide is preferably 700 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less. When the average particle diameter of cerium oxide is 700 μm or less, it becomes easy to bond an adherend having a fine area of the bonded portion. The lower limit of the average particle diameter of cerium oxide is about 0.2 μm. The average particle diameter of cerium oxide can be measured using a light diffraction / scattering particle size distribution meter (for example, trade name “COULTER N5” manufactured by COULTER Electronics). Specifically, a measurement sample is prepared by measuring an appropriate amount of cerium oxide and diluting with water as necessary so as to fall within the range of scattered light intensity required by the light diffraction / scattering particle size distribution analyzer. Next, this measurement sample is put into a light diffraction / scattering particle size distribution meter, measured in the scattered light reference mode, and the value obtained as D50 is taken as the average particle diameter.

  The content of the carbon dioxide adsorbent in the resin composition is preferably 1 to 70 parts by mass, more preferably 1 to 60 parts by mass with respect to 100 parts by mass of the urethane prepolymer, and 1.5 to More preferably, it is 55 mass parts. When the content of the carbon dioxide adsorbent is 1 part by mass or more, it becomes easy to suppress foaming due to carbon dioxide generated during moisture curing of the resin composition, and when it is 70 parts by mass or less, the viscosity of the resin composition is lowered. Can do. In addition, content of the urethane prepolymer in a resin composition is based on the total amount of a polyol component and an isocyanate component.

(Other ingredients)
In the resin composition according to the present embodiment, an appropriate amount of a thermoplastic polymer, a tackifier resin, a catalyst, an antioxidant, a pigment, an ultraviolet absorber, a surfactant, a flame retardant, a filler, and the like is blended as necessary. May be.

  Examples of the thermoplastic polymer include polyurethane, ethylene copolymer, propylene copolymer, vinyl chloride copolymer, acrylic copolymer, and styrene-conjugated diene block copolymer. Examples of tackifying resins include rosin resins, rosin ester resins, hydrogenated rosin ester resins, terpene resins, terpene phenol resins, hydrogenated terpene resins, petroleum resins, hydrogenated petroleum resins, coumarone resins, ketone resins, styrene resins, A modified styrene resin, a xylene resin, and an epoxy resin are mentioned. Examples of the catalyst include dibutyltin dilaurate, dibutylthione octate, dimethylcyclohexylamine, dimethylbenzylamine, and trioctylamine.

  Examples of the antioxidant include hindered phenol-based antioxidants, amine-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants.

  Examples of the pigment include organic pigments such as azo pigments and copper phthalocyanine pigments, and inorganic pigments such as carbon black, titanium oxide, zinc oxide, zinc sulfide, chromium oxide, and petiole.

  Examples of the filler include metal oxides such as silica, alumina, zinc oxide, magnesium oxide, barium oxide, calcium oxide, and strontium oxide, and magnesium hydroxide, barium hydroxide, calcium hydroxide, strontium hydroxide, and the like. A metal hydroxide is mentioned.

  The open time of the resin composition according to this embodiment is preferably 30 to 300 seconds, more preferably 45 to 280 seconds, and still more preferably 60 to 240 seconds. If the open time is 30 seconds or more, an adhesive force is easily developed immediately after bonding, and if it is 300 seconds or less, there is an advantage that the bonding time can be increased.

  From the viewpoint of having excellent coating properties on the adherend, the viscosity measured using the rotational viscometer of the resin composition according to this embodiment is preferably 15 Pa · s or less at 120 ° C., and 13 Pa · It is more preferably s or less, and further preferably 10 Pa · s or less. The lower limit of the viscosity is not limited, but may be 2 Pa · s or more at 120 ° C., for example.

[Method for Producing Resin Composition]
The resin composition according to this embodiment is produced by a method including a step of obtaining a urethane prepolymer having an isocyanate group by reacting a polyol component and an isocyanate component.

  The resin composition according to the present embodiment may be prepared by, for example, a method of obtaining a urethane prepolymer having an isocyanate group by reacting a polyol component and an isocyanate component in the presence of a carbon dioxide adsorbent. You may produce by the method of mixing a carbon dioxide adsorbent, after making the component and an isocyanate component react and obtaining the urethane prepolymer which has an isocyanate group.

[Hot melt adhesive]
The hot melt adhesive of the present embodiment (hereinafter sometimes abbreviated as “adhesive”) is a moisture-curing reactive hot melt adhesive and includes the resin composition. That is, the adhesive according to the present embodiment includes a urethane prepolymer having an isocyanate group and a carbon dioxide adsorbent. In general, a moisture-curable reactive hot-melt adhesive is increased in molecular weight by reacting with moisture in the air or moisture on the surface of the adherend, and exhibits adhesiveness and the like.

  The adhesive according to this embodiment has an applicability capable of adhering parts at a minimum portion, and has excellent adhesion to an adherend and suppresses foaming due to carbon dioxide generated during curing. Has a suppressive effect. In addition, since the adhesive according to the present embodiment is a solventless adhesive, it has a low load on the environment and the human body, can be bonded for a short time, and is a one-component adhesive. Easy to handle.

  Adhesives according to this embodiment can adhere to adherends by applying to the adherend surface, while having excellent applicability capable of adhering parts in a particularly small portion, It combines excellent adhesion, impact resistance, foam suppression during curing, and high reliability. The adhesive according to the present embodiment can be suitably applied when various substrates are to be bonded in a high humidity environment.

[paint]
The paint of the present embodiment is a moisture curable paint and includes the above resin composition. That is, the coating material according to the present embodiment includes a urethane prepolymer having an isocyanate group and a carbon dioxide adsorbent.

  The coating material according to the present embodiment has excellent coating properties for various construction surfaces, and foaming at the time of curing can be suppressed, and a coating film excellent in adhesiveness can be formed. Although it does not specifically limit as a construction surface, For example, the coating film which is excellent in waterproofness can be formed in the roof, floor, wall, etc. of a structure using the coating material which concerns on this embodiment.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to these Examples. In addition, unless there is particular notice, a part is a mass part.

(Polyol component)
As the polyester polyol, polyester polyol a (crystalline polyester polyol obtained by using adipic acid and 1,6-hexanediol as main components, hydroxyl number: 2, Mn: 5000), polyester polyol b (mainly adipic acid and ethylene glycol). Crystalline polyester polyol obtained as a component, number of hydroxyl groups: 2, Mn: 2000), polyester polyol c (amorphous polyester polyol obtained based on isophthalic acid and neopentyl glycol as main components, number of hydroxyl groups: 2, Mn: 2000) was prepared. Polypropylene glycol (hydroxyl number: 2, Mn: 2000) was prepared as a polyether polyol.

(Isocyanate component)
As the isocyanate component, diphenylmethane diisocyanate (isocyanate group number: 2, trade name “Millionate MT” manufactured by Tosoh Corporation) was prepared.

(Cerium oxide)
20 g of cerium carbonate (Ce ₂ (CO ₃ ) ₃ · 8H ₂ O) was placed in an electric furnace, heated to 120 ° C. at 5 ° C./min, and then maintained at 120 ° C. for 1 hour. Subsequently, after heating up to 300 degreeC at 5 degree-C / min, it baked at 300 degreeC for 1 hour, and obtained cerium oxide.

(Examples 1-5)
Polyester polyol a5 parts, polyester polyol b40 parts, polyester polyol c35 parts, polypropylene glycol 20 parts and cerium oxide 40 parts, which have been dehydrated in advance by a vacuum dryer, are uniformly mixed, and then 25 parts of diphenylmethane diisocyanate is further added and mixed uniformly. did. Next, the obtained mixture was reacted at 110 ° C. for 1 hour, and further degassed and stirred under reduced pressure at 110 ° C. for 1 hour to obtain a resin composition containing a urethane prepolymer having an isocyanate group and cerium oxide.

(Examples 2 to 5)
A resin composition was obtained in the same manner as in Example 1 except that the blending amount of cerium oxide was changed to the amount shown in Table 1.

(Comparative Example 1)
A resin composition was obtained in the same manner as in Example 1 except that cerium oxide was not blended.

  Each characteristic of the resin composition obtained in Examples 1-5 and Comparative Example 1 was evaluated as follows. The results are shown in Table 1.

(viscosity)
Using a No. 4 rotor, the melt viscosity of the resin composition (sample amount: 15 g) at a rotor rotational speed of 50 rpm and 120 ° C. was measured using a BH-HH type small-scale rotational viscometer (manufactured by Toki Sangyo Co., Ltd.).

(Foam suppression)
After applying a resin composition on a polycarbonate film under the conditions of a temperature of 25 ° C. and a humidity of 50% to form a coating film having a thickness of 300 μm, the condition was changed to 35 ° C. and 80%, and the film was visually observed. The inside was observed. Table 1 shows the case where the decrease in foaming was confirmed inside the film, and “B” the case where no decrease in foaming was confirmed inside the film.

(Adhesiveness)
The resin composition was melted at 100 ° C., and the adhesive layer was 1 mm long × 25 mm wide × 100 μm thick on a polycarbonate plate (25 mm long × 75 mm wide × 2 mm thick) in an environment of temperature 23 ° C. and humidity 50%. Then, a polycarbonate plate (length 25 mm × width 75 mm × thickness 2 mm) was pressure-bonded onto the adhesive layer to prepare a test piece. After standing for 1 day in an environment of a temperature of 23 ° C. and a humidity of 50%, a shear test (tensile speed: 10 mm / min) was performed to measure the adhesive strength (MPa). The same test was performed by changing the polycarbonate plate to a SUS plate and a Glass plate, and the adhesive strength (MPa) was measured.

(Mechanical properties)
After the resin composition was melted at 100 ° C., a test piece formed into a length of 15 mm × width of 40 mm × thickness of 100 μm was prepared and left to stand in a constant temperature and humidity chamber at a temperature of 23 ° C. and a humidity of 50% for 7 days. Using AGS-X (manufactured by Shimadzu Corporation), the tensile modulus (MPa), breaking strength (MPa) and breaking elongation (%) of the test piece were measured according to JIS K-7127.

  The resin compositions obtained in Examples 1 to 5 have a low viscosity at 120 ° C., excellent coating workability, and excellent foam suppression performance, and have good adhesion to various substrates. Indicated. On the other hand, the resin agent composition of Comparative Example 1 was unable to suppress foaming during curing, and was unable to measure adhesiveness and mechanical properties.

Claims (7)

  A resin composition comprising a urethane prepolymer having an isocyanate group and a carbon dioxide adsorbent.   The resin composition according to claim 1, wherein the carbon dioxide adsorbent contains at least one selected from the group consisting of zeolite, activated carbon, and cerium oxide.   The resin composition according to claim 1 or 2, wherein the carbon dioxide adsorbent contains cerium oxide.   The resin composition according to any one of claims 1 to 3, comprising 1 to 60 parts by mass of the carbon dioxide adsorbent with respect to 100 parts by mass of the urethane prepolymer.   The resin composition according to any one of claims 1 to 4, which is a moisture curable type.   The coating material containing the resin composition as described in any one of Claims 1-5.   The hot-melt-adhesive containing the resin composition as described in any one of Claims 1-5.