JP2008274131A - One-pack moisture-curing type urethane-based hot melt adhesive composition and method for using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-pack moisture-curing type urethane-based hot melt adhesive composition having excellent initial quick curability and sufficient adhesive strength after moisture curing and to provide a method for using the same. <P>SOLUTION: The one-pack moisture-curing type urethane-based hot melt adhesive composition comprises a urethane prepolymer having at least one isocyanate group and at least one (meth)acryloyl group in the molecule and has photo-curability. The method for using the one-pack moisture-curing type urethane-based hot melt adhesive comprises a step of coating each adherend surface of mutually bonded adherends with the one-pack moisture-curing type urethane-based hot melt adhesive composition, forming coated films, then irradiating each coated film with light so as to provide 100-3,000 mJ/cm<SP>2</SP>cumulative quantity of light, providing pre-cured films, subsequently mutually bringing the pre-cured films into contact and bonding the films. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a one-component moisture-curable urethane-based hot melt adhesive composition and a method for using the same. More specifically, the present invention relates to a one-part moisture curable urethane hot melt adhesive composition having an isocyanate group and a (meth) acryloyl group in the molecule and having both photocurability and moisture curable properties, and It relates to its usage.

  One-component moisture-curing urethane hot-melt adhesive based on urethane prepolymers with isocyanate groups in the molecule is applied to the adherend in a molten state, and after cooling and solidification, it exists in the adherend or air Due to the moisture, the reaction of the isocyanate group proceeds to form a crosslinked structure and cure. In this one-component moisture-curing urethane hot melt adhesive, higher adhesive strength and heat resistance are expressed by molecular growth reaction of urethane prepolymer than other hot melt adhesives (for example, Patent Document 1 and 2).

Japanese Patent Laid-Open No. 11-323301 JP-A-8-259923

However, the conventional one-part moisture-curing urethane hot melt adhesive having an isocyanate group in the molecule requires a predetermined time for initial curing, and after bonding, external force is applied to the joint, such as moving the work to the next process. Sufficient time is required before the additional work can be performed.
In addition, one-component moisture-curing urethane hot melt adhesives have both excellent adhesion and heat resistance, but when general-purpose polyester polyols, polyether polyols, etc. are used as raw material polyols, polyethylene, ethylene -Adhesive strength to olefinic adherends such as propylene-diene rubber is weak, and the surface of the adherend needs to be surface treated by corona treatment, primer treatment or the like. Furthermore, when polyolefin polyol is used for the purpose of improving the adhesion, since this polyol is hydrophobic, the diffusion of moisture into the inside of the adhesive coating film is slow, and this diffusion becomes the rate-determining. There is a problem that a long time is required for curing as compared with the case where it was. Thus, when the adherend is a polyolefin-based material, it is not easy to achieve both sufficient fast curability and excellent adhesiveness.

  The present invention has been made in view of the above-described conventional problems, and has both photocurability and moisture curability, particularly excellent initial rapid curability, and sufficient adhesive strength after moisture curing. It is an object of the present invention to provide a one-component moisture-curable urethane-based hot-melt adhesive composition (hereinafter, also referred to as “hot-melt adhesive composition”) having the following. Furthermore, even when polyolefin polyol is used, the initial curing is performed by photocuring, so that it has sufficient fast curing properties and excellent adhesion and heat resistance even with polyolefin-based adherends. It aims at providing the hot-melt-adhesive composition which expresses, and its usage method.

The present invention is as follows.
1. One-component moisture-curable urethane hot melt adhesive composition containing a urethane prepolymer having at least one isocyanate group and at least one (meth) acryloyl group in the molecule, and having photocurability .
2. 1. The above (meth) acryloyl group possessed by the urethane prepolymer is from 5 to 80 mol% when the isocyanate group possessed by the urethane prepolymer is 100 mol%. The one-component moisture-curable urethane-based hot melt adhesive composition described in 1.
3. 1. The above urethane prepolymer having an aliphatic saturated hydrocarbon skeleton. Or 2. The one-component moisture-curable urethane-based hot melt adhesive composition described in 1.
4). 2. The above 3. used for polyolefin substrate. The one-component moisture-curable urethane-based hot melt adhesive composition described in 1.
5. 1. A photopolymerization initiator having photosensitivity to light having a wavelength of 200 to 600 nm. To 4. The one-component moisture-curable urethane-based hot melt adhesive composition according to any one of the above.
6). Above 1. To 5. The one-component moisture-curable urethane-based hot melt adhesive composition according to claim 1, wherein the one-component moisture-curable urethane-based hot melt adhesive composition is applied to each of the adherend surfaces to be adhered to each other. Apply to form a coating film, and then irradiate each coating film with light so that the integrated light quantity is 100 to 3000 mJ / cm ² to form a pre-cured film, and then contact the pre-cured films with each other A method for using a one-component moisture-curing urethane hot melt adhesive, comprising the steps of:
The “(meth) acryloyl group” means an acryloyl group or a methacryloyl group.

The one-component moisture-curable urethane hot melt adhesive composition of the present invention has at least one isocyanate group and at least one (meth) acryloyl group in the molecule, and combines photocurability and moisture-curability. Have. Therefore, it can be set as the hot-melt-adhesive composition which has sufficient quick-curing property and the outstanding adhesiveness collectively.
Moreover, when the isocyanate group which a urethane prepolymer has is made into 100 mol%, when (meth) acryloyl group is 5-80 mol%, the moisture sclerosis | hardenability by an isocyanate group and photocurability by a (meth) acryloyl group. Each of these characteristics can be sufficiently expressed, and a hot melt adhesive composition having both excellent quick curability and adhesiveness can be obtained.
Further, when a urethane prepolymer having an aliphatic saturated hydrocarbon skeleton is contained, a hot melt adhesive composition having sufficient initial adhesive properties in addition to sufficient adhesion to polyolefin-based adherends. be able to.
Moreover, when it contains a photopolymerization initiator having photosensitivity to light having a wavelength of 200 to 600 nm, it can be photocured by irradiating light with a wide range of wavelengths from ultraviolet light to visible light. It can be a melt adhesive composition.

  According to the method of using the one-component moisture-curable hot-melt adhesive composition of the present invention, the initial rapid curability can be enhanced by photocuring, for example, external force is applied to the joint, such as moving the workpiece to the next process. The added work can be performed in a short time after bonding, and the work efficiency can be improved.

The present invention will be described in detail below.
[1] One-part moisture curable urethane-based hot melt adhesive composition One-part moisture-curable urethane-based hot melt adhesive composition of the present invention comprises at least one isocyanate group and at least one (meth) acryloyl in the molecule. It contains a urethane prepolymer having a group and has photocurability.

  The “urethane prepolymer” is a urethane prepolymer having in the molecule at least one isocyanate group and at least one (meth) acryloyl group. This urethane prepolymer is prepared by, for example, reacting an excess polyisocyanate with a polyol having two or more hydroxyl groups to produce an isocyanate prepolymer, and then adding a (meth) acrylate compound further having a functional group to the prepolymer. It can be made to react. The position where the isocyanate group and the (meth) acryloyl group are bonded may be the terminal of the main chain of the prepolymer or the terminal of the side chain. Moreover, although the number of an isocyanate group and a (meth) acryloyl group is not specifically limited, Usually, it is 1-3 each. Furthermore, the number of isocyanate groups and (meth) acryloyl groups may be the same or different.

  The hot melt adhesive composition contains a urethane prepolymer having at least one isocyanate group and at least one (meth) acryloyl group in the molecule, and may further contain another urethane prepolymer. Examples of other urethane prepolymers include urethane prepolymers having only isocyanate groups and urethane prepolymers having only (meth) acryloyl groups. Thus, when other urethane prepolymers are contained, the urethane prepolymer having at least one isocyanate group and at least one (meth) acryloyl group in the molecule when the total amount of the urethane prepolymer is 100% by mass. The mass ratio of the polymer is preferably 10% by mass or more, particularly preferably 30% by mass or more.

The ratio of the isocyanate group and (meth) acryloyl group of the urethane prepolymer having at least one isocyanate group and at least one (meth) acryloyl group in the molecule is not particularly limited, but when the isocyanate group is 100 mol% Further, the (meth) acryloyl group is preferably 5 to 80 mol%, particularly preferably 8 to 80 mol%. If the (meth) acryloyl group is 5 to 80 mol%, the initial adhesive strength after photocuring and the adhesive strength after moisture curing, both at room temperature (for example, 23 ° C.) and at a high temperature (for example, 120 ° C.). Both of them can be made into a hot melt adhesive composition having both excellent fast curability and adhesiveness.
The molar equivalent of the isocyanate group in the urethane prepolymer can be measured by reacting with excess di-n-butylamine and back titrating the excess amine with hydrochloric acid. The molar equivalent of the (meth) acryloyl group can be measured by reacting with excess bromine, reacting the remaining bromine with potassium iodide, and titrating the resulting iodine with a standard solution of sodium sulfate.

  The polyol used for production of the urethane prepolymer is not particularly limited, and various polyols can be used. Examples of the polyol include polyether polyol, polyester polyol, polyolefin polyol, and polybutadiene polyol. These polyols may be used alone or in combination of two or more. Different types of polyols can also be used in combination.

  As the polyether polyol, a polyol obtained by random addition polymerization or block addition polymerization of alkylene oxide to a starting material having two or more active hydrogens can be used. As such a polyol, an alkylene oxide such as ethylene oxide, propylene oxide, trimethylene oxide and butylene oxide is added to an active hydrogen compound such as ethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylolpropane and pentaerythritol. Examples include polyols obtained by polymerization.

Polyester polyols include low molecular weight polyols such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, hexanediol, glycerin, trimethylolpropane and pentaerythritol, succinic acid, adipic acid, maleic acid, fumaric acid, phthalic acid, anhydrous Examples thereof include polyols produced by a condensation reaction with carboxylic acids such as succinic acid, maleic anhydride and phthalic anhydride, and anhydrides thereof.
Examples of the polyolefin polyol include hydrogenated polybutadiene polyol and hydrogenated polyisoprene polyol.

The polyisocyanate used for producing the urethane prepolymer is not particularly limited, and various polyisocyanates can be used. As this polyisocyanate, toluene diisocyanate (TDI), crude TDI, 4,4′-diphenylmethane diisocyanate (MDI), crude MDI, hydrogenated MDI, isophorone diisocyanate, hexamethylene diisocyanate, 1,5-naphthalene diisocyanate and paraphenylene diisocyanate Etc.
Only one type of polyisocyanate may be used, or two or more types may be used in combination, but only one type is often used.
Further, the amount ratio of the polyisocyanate and the polyol is not particularly limited, but it is preferable that the molar ratio of the isocyanate group and the hydroxyl group is 1.1 to 2.0.

The (meth) acrylate compound used for introducing the (meth) acryloyl group into the urethane prepolymer is not particularly limited, and various (meth) acrylate compounds can be used. As this (meth) acrylate compound, a (meth) acrylate compound having a hydroxyl group, a (meth) acrylate compound having an isocyanate group, a (meth) acrylate compound having an epoxy group, dehydration of a polyester polyol and (meth) acrylic acid A polyester (meth) acrylate compound which is a condensate, a polyalkylene glycol mono (meth) acrylate compound and the like can be mentioned. Of these, (meth) acrylate compounds having a hydroxyl group are often used.
Only one (meth) acrylate compound may be used, or two or more (meth) acrylate compounds may be used in combination. Different types of (meth) acrylate compounds can also be used in combination.

  Examples of the (meth) acrylate compound having a hydroxyl group include hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxy Examples include octyl (meth) acrylate, pentaerythritol tri, di or mono (meth) acrylate, and trimethylolpropane di or mono (meth) acrylate.

  The (meth) acrylate compound having an epoxy group is a compound obtained by adding (meth) acrylic acid to an epoxy resin. The epoxy resin may be an aromatic epoxy resin or an aliphatic epoxy resin. Examples of the aromatic epoxy resin include resorcinol diglycidyl ether, bisphenol A, bisphenol F, and a novolac type epoxy resin. Examples of the aliphatic epoxy resin include diglycidyl ethers of alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol and 1,6-hexanediol, and polyalkylene glycols such as diglycidyl ethers of polyethylene glycol and polypropylene glycol. Diglycidyl ether is mentioned.

  Examples of the polyester (meth) acrylate compound include a dehydration condensate of a polyester polyol and (meth) acrylic acid. Examples of the polyester polyol include a reaction product of a polyol and a carboxylic acid or an anhydride thereof. Examples of the polyol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane dimethanol, and 1,6. -Low molecular weight polyols such as hexanediol and trimethylolpropane, and alkylene oxide adducts thereof. Examples of the carboxylic acid or its anhydride include carboxylic acids such as phthalic acid, adipic acid, succinic acid, fumaric acid, and maleic acid, or anhydrides thereof.

Examples of the polyalkylene glycol mono (meth) acrylate compound include polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, and polytetramethylene glycol mono (meth) acrylate.
The compounding quantity of a (meth) acrylate compound is not specifically limited, It can be set as the compounding quantity which the mass ratio of the isocyanate group in a urethane prepolymer and a (meth) acryloyl group becomes as above.

[2] Photopolymerization initiator Since the hot melt adhesive composition of the present invention has photocurability, it is possible to promote particularly early curing as described above.
The photopolymerization initiator is not particularly limited, and various photopolymerization initiators can be used. Examples of the photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide (for example, trade name “Lucirin TPO” manufactured by BASF), benzoins such as benzoin, benzoin methyl ether, benzoin propyl ether, acetophenone, Acetophenones such as 2,2-dimethoxy-2-phenylacetophenone and 1,1-dichloroacetophenone, anthraquinones such as 2-methylanthraquinone, 1-chloroanthraquinone and 2-amylanthraquinone, 2,4-dimethylthioxanthone, 2- Thioxanthones such as chlorothioxanthone and 2,4-diisopropylthioxanthone, ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal, and benzophenone, methylbenzophenone, , Benzophenones such as 4'-dichloro benzophenone. These photopolymerization initiators may be used alone or in combination of two or more. Different types of photopolymerization initiators can also be used in combination.

As a photoinitiator, the photoinitiator which has photosensitivity with respect to the light of wavelength 200-600 nm is preferable. If it is such a photoinitiator, it can be photocured by irradiating light of a wide range of wavelengths from ultraviolet light to visible light. Examples of the photopolymerization initiator having photosensitivity to light having a wavelength of 200 to 600 nm include 2,2-dimethoxy-1,2-diphenyl in addition to the above 2,4,6-trimethylbenzoyldiphenylphosphine oxide. Examples include ethane-1-one and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1.
Although the compounding quantity of a photoinitiator is not specifically limited, When the polyol used for manufacture of a urethane prepolymer is 100 mass parts, it shall be 0.3-10 mass parts, especially 0.5-5 mass parts. Can do.

[3] Other components In the hot melt adhesive composition, other components such as various additives can be blended in addition to the urethane prepolymer and the photopolymerization initiator. Examples of other components include a catalyst, a plasticizer, a filler, an antioxidant, and a pigment.

Examples of catalysts include organometallic catalysts such as titanium acetylacetonate, dibutyltin diacetate, and dibutyltin dilaurate, monoamines such as triethylamine, and amines such as diamines such as N, N, N ′, N′-tetramethylethylenediamine. A catalyst etc. are mentioned. These catalysts may be used alone or in combination of two or more.
Examples of the plasticizer include dioctyl phthalate, dibutyl phthalate, dioctyl adipate, diisodecyl adipate, trioctyl phosphate, tris (chloroethyl) phosphate, propylene glycol adipate polyester, butylene glycol adipate polyester, and the like. These plasticizers may be used alone or in combination of two or more.
Examples of the filler include calcium carbonate, carbon black, clay, talc, titanium oxide, slaked lime, kaolin, and zeolite. These fillers may use only 1 type and can also use 2 or more types together.
Examples of the antioxidant include butylhydroxytoluene, butylhydroxyanisole, diphenylamine, phenylenediamine, and triphenyl phosphite. These antioxidants may be used alone or in combination of two or more.
Examples of the pigment include inorganic pigments such as titanium dioxide, zinc oxide, ultramarine blue, and bengara, and organic pigments such as azo pigments and copper phthalocyanine. These pigments may be used alone or in combination of two or more.

  Although the compounding quantity of said other component is not specifically limited, When a urethane prepolymer is 100 mass parts, a catalyst is 0.005-0.1 mass part, a plasticizer is 5-50 mass parts, and a filler is 5 to 250 parts by mass, 0.1 to 5 parts by mass of the antioxidant, and 0.1 to 10 parts by mass of the pigment. These other components are usually blended together at the same time, but may be divided and blended for the purpose of improving pot life and work efficiency. These other components may be blended in advance when the hot melt adhesive composition is produced, or may be blended immediately before application to the adherend.

[4] Adhering material The one-component moisture-curable urethane-based hot melt adhesive composition of the present invention includes various plastic adhering materials such as polyolefin, polyester, nylon and epoxy, and various metals such as aluminum, iron and stainless steel. It can be used for adhesion of various types of adherends such as various types of adherends made of rubber, such as made of adherend, chloroprene rubber and natural rubber, and the material of the adherend is not particularly limited. However, the adherend is an ethylene unit such as polyethylene, polypropylene, ethylene-propylene-diene rubber (EPDM), or a copolymer having a propylene unit (when the copolymer is 100% by mass, the ethylene unit and / or propylene). The unit is 60% by mass or more, particularly 80% by mass or more.) When a polyolefin such as a cycloolefin (co) polymer is used, a urethane prepolymer produced using a polyester polyol or a polyether polyol as a polyol is contained. In such a hot melt adhesive, sufficient adhesion and adhesion strength may not be exhibited. In this case, if the surface of the adherend is subjected to surface treatment by corona discharge treatment, primer treatment, or the like, adhesion and adhesion strength can be improved. If surface treatment is performed in this manner, adhesion and adhesive strength are improved, but a separate processing step is required.

  When the adherend is made of polyolefin as described above, if the polyolefin polyol is used as a polyol and an aliphatic saturated hydrocarbon skeleton is introduced into the urethane prepolymer, adhesion and adhesion to the polyolefin adherend Strength can be improved. However, the hydrophobicity of the urethane prepolymer is increased, the diffusion of moisture into the coating film is delayed, and only the conventional isocyanate groups are compared with the urethane prepolymers produced using polyester polyols and polyether polyols. The urethane prepolymer having a long time requires curing.

  The urethane prepolymer contained in the hot melt adhesive composition of the present invention has a (meth) acryloyl group in addition to the isocyanate group. Therefore, even if an aliphatic saturated hydrocarbon skeleton is introduced into the urethane prepolymer, the initial curing can be sufficiently accelerated by photocuring. Therefore, even if a long time is required for subsequent moisture curing, work that applies external force to the joint, such as moving the workpiece to the next process, can be performed in a short time after bonding, and work efficiency can be improved. Can do.

  Particularly useful when the adherend is made of polyolefin, the urethane prepolymer introduced with an aliphatic saturated hydrocarbon skeleton may be an aliphatic saturated hydrocarbon skeleton, and part of the aliphatic prepolymer may be aliphatic. It may be a saturated hydrocarbon skeleton. In addition, the total amount of the urethane prepolymer used may be a prepolymer having an aliphatic saturated hydrocarbon skeleton, a prepolymer having an aliphatic saturated hydrocarbon skeleton, and a prepolymer having no aliphatic saturated hydrocarbon skeleton; May be used in combination. The ratio of the aliphatic saturated hydrocarbon skeleton and the mass ratio of the prepolymer having the aliphatic saturated hydrocarbon skeleton in the case of combined use can be set depending on the kind of the adherend and the required adhesive strength.

[5] Method of using hot melt adhesive.
The method of using the hot melt adhesive of the present invention is not particularly limited. For example, a coating film is formed by applying the hot melt adhesive composition of the present invention to the respective adherend surfaces to be adhered to each other. Thereafter, each coating film is irradiated with light so that the integrated light quantity becomes 100 to 3000 mJ / cm ² to form a pre-cured film, and then the pre-cured film is brought into contact with each other and used in a method including a step of bonding. can do.

The adherend is not particularly limited, and the above-described various adherends can be used. In addition, the hot-melt adhesive composition of the present invention can sufficiently accelerate the initial curing, even if it is an adherend made of polyolefin as described above. Furthermore, the integrated light quantity of light irradiated is 100~3000mJ / cm ^2, it is preferable that 300~2000mJ / cm ^2. If this integrated light quantity is 100 to 3000 mJ / cm ² , the initial curing is sufficiently promoted, and the adherends can be sufficiently adhered to each other without being excessively cured, and the adhesive strength is sufficient. be able to.
In addition to the above-described bonding step, this method of use can usually include a curing step for promoting moisture curing and the like.

In the above method of use, a hot melt adhesive composition is applied to each of the adherend surfaces of the adherends to be bonded to each other, and each coating film is irradiated with light to form a precured film, and then the precured film Although they are brought into contact with each other and bonded to each other, other usage methods can be used. For example, a precured film can be formed on one adherend, and then the other adherend can be adhered to the precured film. In addition, the hot melt adhesive composition is applied to one adherend, or one adherend and the other adherend, and the respective coating films are brought into contact with each other. Pre-curing can also be performed by irradiating light from the direction. Further, when at least one of the adherends is a material that transmits light to the coating film, it can be pre-cured by the light transmitted through the adherend.
The thickness of the coating film is not particularly limited, but is preferably 10 to 500 μm, and more preferably 50 to 200 μm.

[6] Method for Producing Hot Melt Adhesive Composition The method for producing the hot melt adhesive composition of the present invention is not particularly limited. For example, the hot melt adhesive composition can be produced as follows.
A polyol and a catalyst are charged into a reaction vessel, heated under vacuum, and stirred. Thereafter, an inert gas such as nitrogen gas is introduced and the pressure is increased to normal pressure, and then polyisocyanate is blended, stirred, and reacted for a predetermined time while mixing. Thereafter, the (meth) acrylate compound and the catalyst are blended, and stirred and mixed. Next, the polyisocyanate is blended and stirred and mixed, and then a photopolymerization initiator, a catalyst, and a polymerization inhibitor as necessary are blended, and further stirred and mixed. Thereby, the hot-melt-adhesive composition which contains the urethane prepolymer which has an isocyanate group and a (meth) acryloyl group in a molecule | numerator, and also has photocurability together with moisture sclerosis | hardenability can be manufactured.

Hereinafter, the present invention will be specifically described by way of examples.
[1] Production of hot melt adhesive composition Example 1
120 parts by mass of hydrogenated polybutadiene polyol (trade name “Polytail H”, hydroxyl value 48, manufactured by Mitsubishi Chemical Co., Ltd.) and 0.012 parts by mass of dibutyltin dilaurate (catalyst) were placed in a flask and vacuumed (20 torr The following was stirred for 30 minutes at 100 ° C. and mixed. Thereafter, nitrogen gas was introduced to normal pressure, 22.3 parts by mass of isophorone diisocyanate was blended, stirred at 100 ° C. in a nitrogen stream, and reacted for 1 hour while mixing. Next, the temperature was lowered to 80 ° C., 0.014 parts by mass of dibutyltin dilaurate and 1.3 parts by mass of hydroxyethyl methacrylate (hereinafter abbreviated as “HEMA”) were blended, and the nitrogen stream was applied at 80 ° C. Stir for 1 hour and mix. Thereafter, 14.4 parts by mass of an aliphatic triisocyanate compound was blended and stirred at 80 ° C. for 30 minutes and mixed. Next, 0.16 parts by weight of dibutyltin dilaurate, 1.4 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name “Lucirin TPO”) and 0.14 parts by weight of a polymerization inhibitor (Wako Pure Chemical Industries, Ltd.) Manufactured, trade name "Q-1301"), further stirred for 30 minutes at 80 ° C, mixed and hot containing mainly a urethane prepolymer having an isocyanate group and a (meth) acryloyl group at the molecular end. A melt adhesive composition was produced.

Examples 2-5
A hot melt adhesive composition was produced in the same manner as in Example 1 except that the amount of each component was as shown in Table 1.
Comparative Example 1
A hot melt adhesive composition containing an isocyanate-terminated prepolymer was produced in substantially the same manner as in Example 1 except that HEMA was not blended.
Comparative Example 2
A hot melt adhesive composition was produced in the same manner as in Example 1 except that no photopolymerization initiator was added.
Comparative Example 3
Performance was evaluated in the same manner as in the Examples using a polyester-based moisture-curable hot melt adhesive that does not have photocurability.

尚、数値の単位はすべて質量部である。

All units of numerical values are parts by mass.

[2] Performance Evaluation (1) Effect of Curing Time on Adhesive Strength (a) Preparation of Test Specimens Each of the hot melt adhesive compositions of Example 1 and Comparative Examples 1 and 2 was adjusted to 120 ° C. And melted on a hot plate. Thereafter, a hot melt adhesive composition is applied to the end faces in the length direction of two EPDM adherends (20 mm × 20 mm × 100 mm prismatic shape) (application area is 20 × 20 mm). The thickness of the coating film is 100 μm.) Immediately after coating, the coating film was irradiated with light so that the adjusted light amount was 1000 mJ / cm ^2, and then a preliminary formed on the end face of each adherend. The cured film was brought into contact and adhered to prepare a test piece.
As the irradiator, model “UIS-25102” (metal halide lamp 150W) manufactured by USHIO INC. Was used. Further, the integrated light amount was measured by using an integrated light meter (model “UIT-150” manufactured by Ushio Electric Co., Ltd.). Furthermore, the model “UVD-C365” manufactured by USHIO INC. Was used as the light receiver.

(B) Measurement of tensile adhesive strength Immediately after producing the test piece produced in (a) above (in Table 2, it is indicated as immediately after adhesion, this means that 2 minutes have elapsed after adhesion). Then, after curing for a predetermined time as shown in Table 2 in an atmosphere of 40 ° C. and 65% RH, the tensile bond strength was measured, and the influence of the curing time on the bond strength was examined. The adhesive strength was measured according to JIS-K6850, at a temperature of 23 ° C. and a tensile speed of 200 mm / min. The results are listed in Table 2.
In Table 2, CF means cohesive failure and SF means base material failure, and CF + SF means coexistence of cohesive failure and base material failure.

According to the results of Table 2, in Example 1, the tensile bond strength was sufficiently large as 10 N / cm ² immediately after bonding, and the bond strength increased with the curing time, and after 72 hours, 51 N / cm ² . It turns out that it has excellent adhesiveness. On the other hand, in Comparative Example 1, it is not adhered immediately after, and is 9 N / cm ² after curing for 2 hours. This means that the movement to the next process or the like cannot be performed unless two hours or more have elapsed since the bonding. Further, even in Comparative Example 2, since it does not have photocurability, the adhesive strength is smaller, and it is 7 N / cm ² even after curing for 8 hours. It is assumed that they cannot move.

(2) Effect of integrated light quantity on adhesive strength (a) Preparation of test piece The hot melt adhesive composition of Example 1 was melted on a hot plate adjusted to 120 ° C. Thereafter, one of the two EPDM adherends (3 mm × 25 mm × 50 mm plate shape) is hot for a length of 12.5 mm from the end face on one side of the 25 mm wide side face. The melt adhesive composition is applied (the application area is 12.5 × 25 mm. The thickness of the coating film is 100 μm). The test piece was produced by irradiating light so that it would be ˜2000 mJ / cm ² ), and then adhering one end of the other 25 mm wide side surface to the pre-cured film.
In addition, the apparatus as described in said (1) and (a) was used as an irradiator. In addition, the integrated light amount was measured in the same manner using the integrated light meter described in (1) and (a) above. Furthermore, the apparatus as described in said (1) and (a) was used as a light receiver.

(B) Measurement of tensile shear bond strength Using the test piece prepared in (a) above, after initial curing (30 minutes after bonding) and curing for 92 hours in an atmosphere of 23 ° C. and 65% RH, tensile The shear bond strength was measured, and the effect of the integrated light amount on the bond strength was examined. The measurement was based on JIS-K6850, and the temperature was 23 ° C. and 120 ° C., and the tensile speed was 10 mm / min. The results are shown in Table 3 and FIGS.

According to the results of Table 3 and FIGS. 1 and 2, the initial adhesive strength is small when no light is irradiated, but if the integrated light quantity is 100 mJ / cm ² , You can see that On the other hand, when the integrated light quantity is 2000 mJ / cm ² , no further improvement in the adhesive strength is seen compared to the case of 1000 mJ / cm ² , and when the integrated light quantity exceeds 2000 mJ / cm ² , the adhesive strength is low. It is inferred that it decreases.
In addition, if it cures for 92 hours, it will become sufficient adhesive strength even if light irradiation is not made, but this is due to moisture hardening.

(3) Effect of the acrylation rate on the adhesive strength The tensile shear adhesive strength of each of the hot melt adhesive compositions of Examples 1 to 5 and Comparative Examples 1 to 3, and the integrated light amount as 1000 mJ / cm ² , Using the test pieces prepared in the same manner as in the above (2) and (a), measurement was performed in the same manner as in the above (2) and (b), and the influence of the acrylation rate on the adhesive strength was examined. The results are shown in Table 4 and FIGS.
In addition, this acrylation rate represents the mol% of the (meth) acryloyl group by the percentage when the isocyanate group which a urethane prepolymer has is 100 mol%.

According to the results in Table 4 and FIGS. 3 and 4, when the urethane prepolymer has no (meth) acryloyl group, the initial adhesive strength is small, but if the acrylation rate is 5%, the next step It can be seen that the adhesive strength can be moved to. On the other hand, in Example 5 where the acrylation rate is 100%, the adhesive strength is lower than in Example 4 where it is 50%, and it can be seen that the acrylation rate is preferably less than 100%.
In addition, when cured for 92 hours, even a urethane prepolymer having no (meth) acryloyl group has sufficient adhesive strength, but this is due to moisture curing.

(4) Measurement of melt viscosity Each of the hot melt adhesive compositions of Examples 1 to 5 and Comparative Examples 1 to 3 is heated to 120 ° C to melt and flows into a test tube with an inner diameter of 18 mm from the bottom to a depth of 50 mm. I let you. Then, the rotor of the BM type viscometer was put in and rotated to measure the melt viscosity at 120 ° C. The results are also shown in Table 4.
According to the results in Table 4, it can be seen that there is no specific correlation between the melt viscosity and the adhesive strength.

  The one-component moisture-curing urethane hot melt adhesive composition of the present invention is particularly excellent in initial rapid curability and has sufficient adhesive strength after curing. Even if the adherend is made of polyolefin, the initial curing is sufficiently accelerated. This hot melt adhesive composition can be used in many fields, and can be suitably used particularly in bonding work in the automobile industry, the machine industry, and the like.

It is a graph showing the correlation with the integrated light quantity of the light irradiated to the coating film, and the tensile shear bond strength measured at 23 degreeC. It is a graph showing the correlation with the integrated light quantity of the light irradiated to the coating film, and the tensile shear bond strength measured at 120 degreeC. It is a graph showing the correlation with the acrylation rate in a urethane prepolymer, and the tensile shear bond strength measured at 23 degreeC. It is a graph showing the correlation with the acrylation rate in a urethane prepolymer, and the tensile shear bond strength measured at 120 degreeC.

Claims (6)

  One-component moisture-curable urethane hot melt adhesive composition containing a urethane prepolymer having at least one isocyanate group and at least one (meth) acryloyl group in the molecule, and having photocurability .   The one-component moisture-curable urethane according to claim 1, wherein the urethane prepolymer has 5 to 80 mol% of the (meth) acryloyl group when the isocyanate group of the urethane prepolymer is 100 mol%. -Based hot melt adhesive composition.   The one-component moisture-curable urethane-based hot melt adhesive composition according to claim 1 or 2, comprising the urethane prepolymer having an aliphatic saturated hydrocarbon skeleton.   The one-component moisture-curable urethane-based hot melt adhesive composition according to claim 3, which is used for a polyolefin adherend.   The one-component moisture-curable urethane-based hot-melt adhesive composition according to any one of claims 1 to 4, comprising a photopolymerization initiator having photosensitivity to light having a wavelength of 200 to 600 nm. A method of using the one-component moisture-curable urethane-based hot melt adhesive according to claim 1,
A coating film is formed by applying the one-component moisture-curing urethane hot melt adhesive composition to each of the adherend surfaces of the adherends to be bonded to each other. A one-part moisture-curing urethane hot melt comprising a step of irradiating light so as to be ˜3000 mJ / cm ² to form a pre-cured film, and then bringing the pre-cured film into contact with each other and bonding them How to use the adhesive.

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