JP4766376B2 - Rubber-based curable hot-melt adhesive composition - Google Patents

Description

The present invention relates to a rubber-based curable hot melt adhesive composition having heat resistance.

In general, hot melt adhesives that require heat resistance include, for example, product assemblies, such as solvent-based two-component curable adhesives, solvent-free two-component curable adhesives that have room temperature fluidity, and moisture. A curable urethane hot melt adhesive is used. Solvent-based two-component curable adhesives have a problem that they cannot be used due to recent environmentally conscious solvent regulations, and solvent-free two-component curable adhesives with room temperature fluidity have a long open time and short handling. It is difficult to balance time, and moisture-curing urethane hot-melt adhesives are difficult to handle between the melting tank and the coating head. There is a problem that the curing characteristics are not constant due to fluctuations in humidity depending on the season.

An example of a solvent-free pressure-sensitive adhesive that cures a pressure-sensitive hot-melt adhesive based on maleic anhydride-modified SEBS with an aluminum chelate to add heat resistance to the ease of handling of a pressure-sensitive hot-melt adhesive is patented It is introduced in Reference 1. However, since the curing reaction between maleic anhydride and the curing agent by the aluminum chelate is extremely fast, the viscosity is increased and the fluidity is lost at the moment when the hot melt adhesive and the aluminum chelating agent are mixed. Therefore, practically, it is impossible to adjust the coating amount with a hot melt applicator.

In addition, the epoxidized diene polymer is polymerized with an aromatic anhydride anhydride at a polymer / aromatic anhydride molar ratio of 0.5 / 1.0 to 2.0 / 1.0 at a temperature of 100 to 200 ° C. for 10 minutes. Non-patent document 1 that causes a curing reaction by bringing into contact for 6 hours has been published, but a special apparatus that maintains at a high temperature is required even if the final cross-linking point is reached at 100 ° C. for 10 minutes. The curing time is too long for use in a simple production line, and the production rate is significantly reduced.
Special Table 2000-506186 Shingo Sugiyama, "Latest Technology of Rubber-based Solventless Adhesives" Convertech, 40, (2002.3)

The problem to be solved is that there is no environmental problem of solvent-based curable adhesives, the inconvenience in handling and processing of moisture-curable polyurethane hot-melt adhesives and conventional two-component curable hot-melt adhesives Provided is a one-component curable rubber-based curable hot-melt adhesive composition that does not have an economic irrationality that requires the adhesive to be discarded before and after.

The present invention is not a moisture curable type, but a rubber-based curable hot melt adhesive composition having a gradient in the curing reaction.

The present invention is a rubber-based curable hot-melt adhesive composition in which a curing accelerator (F) is added to the surface of a hot-melt composition coated product containing an epoxy resin, and heat resistance is imparted by reacting from the surface.

The hot melt composition is preferably a rubber-based curable hot melt adhesive composition comprising the following components (A) to (E).
(A) Acid anhydride-modified copolymer (B) Epoxy resin (C) Non-reactive block copolymer (D) Tackifier (E) Plasticizer

Moreover, as a compounding part number, with respect to 100 mass parts of styrene block copolymers (A) which provided the acid anhydride, 1-100 mass parts of epoxy resin (B) components, non-reactive block copolymer (C) components 1-3000. It is preferable that they are a mass part, 50-24000 mass parts of tackifying resin (C) components, and 5-6000 mass parts of plasticizing oil (D) components.

Furthermore, 10-40% styrene block copolymer (A) component provided with acid anhydride, 0.1-20% epoxy resin (B) component, 1-40% non-reactive block copolymer (C) component, tackifying It is preferable to contain 30 to 70% of resin (D) component and 5 to 30% of plasticized oil (E) component.

In addition, the component (A) is a styrene / butadiene / styrene block copolymer (hereinafter referred to as “SBS”), styrene / isoprene / styrene block copolymer (hereinafter referred to as “SIS”), styrene, containing 0.5 to 5% by mass of an acid anhydride.・ Ethylene butylene / styrene block copolymer (hereinafter referred to as “SEBS”), styrene / ethylene propylene / styrene block copolymer (hereinafter referred to as “SEPS”), and styrene / isobutylene / styrene block copolymer (hereinafter referred to as “SIPS”). It is preferable that it is a type | mold hot-melt-adhesive composition.

  Moreover, the rubber-type curable hot-melt-adhesive composition whose (B) component is an epoxy resin which contains 2-10 reactive epoxy groups in a molecule | numerator is preferable.

  Further, the curing accelerator (F) accelerates the reaction between the acid anhydride and the epoxy, and includes tertiary amines and salts thereof, imidazoles and salts thereof, organic phosphine compounds and salts thereof, and organic acid metal salts. A rubber-based curable hot melt adhesive composition that is at least one type of curing accelerator selected is preferable.

  Moreover, it is preferable that it is a rubber-type curable hot-melt-adhesive composition which added 0.05-5 mass parts of hardening accelerators (F) with respect to 100 mass parts of hot-melt-adhesives.

Moreover, this invention is a rubber-type curable hot-melt-adhesive composition characterized by being used for the adhesive tape in which heat resistance is requested | required.

An object of the present invention is to provide an adhesive having high heat resistance and convenient handling. Furthermore, in the case of using the (F) curing accelerator, the present invention is a rubber-based curing type with higher heat resistance that is more convenient to handle by a method in which a hot melt adhesive is applied and cured on the adhesive after coating. The object is to provide a hot melt adhesive composition.

The present invention is not a moisture curable type, but a rubber-based curable hot melt adhesive composition having a gradient in the curing reaction. The gradient of the curing reaction of the present invention is described in detail in paragraph No. 0037, and the cross section in the depth direction of the hot melt adhesive is measured by microscopic ATR measurement.

The present invention is a rubber-based curable hot-melt adhesive composition in which a curing accelerator (F) is added to the surface of a hot-melt composition coated product containing an epoxy resin, and heat resistance is imparted by reacting from the surface.

  The rubber-based curable hot melt adhesive composition of the present invention comprises (A) an acid anhydride-modified styrene block copolymer as a base polymer, and (B) is crosslinked with an epoxy resin. The curing accelerator (F) is an acid. Those that promote the anhydride / epoxy resin reaction are preferred.

The rubber-based curable hot-melt adhesive composition of the present invention is preferably a rubber-based curable hot-melt adhesive composition comprising the following components (A) to (E).
(A) Acid anhydride-modified copolymer (B) Epoxy resin (C) Non-reactive block copolymer (D) Tackifier (E) Plasticizer

The component (A) is a styrene block copolymer containing 0.5 to 5% by weight of an acid anhydride. Examples of the (A) acid anhydride-modified styrene block copolymer used in the present invention include maleic anhydride-modified styrene-ethylene. A butylene-styrene block copolymer (hereinafter referred to as “maleic anhydride-modified SEBS”) can be mentioned. When the addition amount of the acid anhydride is less than 0.5% by mass, there is a tendency that the reactivity is low and sufficient heat resistance cannot be obtained, and an acid anhydride exceeding 5% by mass is added to the styrene block copolymer. difficult.

  Specific examples of maleic anhydride-modified SEBS include Kraton Polymer Japan Co., Ltd., trade name Kraton FG1901X, Asahi Kasei Co., Ltd., trade name Tuftec M1943.

  The epoxy resin of component (B) of the present invention refers to a monomer, oligomer or polymer having 2 to 10 epoxy groups in one molecule. For example, bisphenol type epoxy resin, orthocresol novolak type epoxy resin, phenol novolak type epoxy resin, alicyclic epoxy resin, biphenyl type epoxy resin, stilbene type epoxy resin, naphthol type epoxy resin, triphenolmethane type epoxy resin, and these These may be used alone or in combination. As the epoxy resin, an epoxy resin having an epoxy equivalent of 100 to 5,000 g / equivalent, more preferably 150 to 1,000 g / equivalent, is more preferably used. For example, trade names “Epicoat 828”, “Epicoat 1001”, and “Epicoat 1004” are available from Japan Epoxy Resin Co., Ltd. When the number of epoxy groups in one molecule is less than 2, there is a tendency that the reactivity is low and sufficient heat resistance cannot be obtained. When the number of epoxy groups in one molecule exceeds 10, the pot life and storage stability tend to be adversely affected.

In addition, the presence of a functional group capable of promoting the ring opening of an acid anhydride in the molecule of the epoxy resin, such as a hydroxyl group or nitrogen, adversely affects the pot life and storage stability of the hot melt adhesive. An epoxy resin having a functional group content capable of promoting the ring opening of 1.0% by mass or less is preferred. For example, there are Japan Epoxy Resin Co., Ltd., trade name Epicoat 825, Daicel Chemical Industries, Ltd., trade name Celoxide 2021, and the like.

  The non-reactive block copolymer (C) used in the present invention is added in order to maintain the tackiness of the hot melt adhesive even after the curing reaction. For example, styrene block copolymer, olefin block copolymer, acrylic block copolymer and There are derivatives thereof. Examples of the non-reactive block copolymer (C) of the present invention include Kraton Polymer Japan Co., Ltd., trade name Clayton G-1726, JSR Corporation, trade name Dynalon 6200P, and the like.

Examples of the (D) tackifying resin used in the present invention include terpene resins, aliphatic petroleum resins, alicyclic petroleum resins, aromatic petroleum resins, coumarone / indene resins, rosin resins, and derivatives thereof. is there. Examples of the tackifier (D) of the present invention include trade name Clearon M115 manufactured by Yasuhara Chemical Co., Ltd.

(E) As the plasticizer, process oil and / or polyolefin-based fluid and / or wax are used. Examples of the (E) plasticizer of the present invention include trade name process oil PW32 manufactured by Idemitsu Kosan Co., Ltd.

In the present invention, an antioxidant such as hindered phenol, a filler such as calcium carbonate, and the like may be appropriately added to the rubber-based curable hot melt adhesive composition as necessary.

  The (F) acid anhydride / epoxy resin curing accelerator used in the present invention is, for example, 1,8-diaza-bicyclo (5,4,0) undecene-7, 1,5-diaza-bicyclo (4). , 3,0) nonene, cycloamidine compounds such as 5,6-dibutylamino-1,8-diaza-bicyclo (5,4,0) undecene-7 and these compounds include maleic anhydride and 1,4-benzoquinone 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1 , 4-benzoquinone, phenyl-1,4-benzoquinone and other quinone compounds, diazophenylmethane, compounds having a π bond such as phenolic resin, and the like having intramolecular polarization Products, benzyldimethylamine, triethanolamine, dimethylaminoethanol, polyoxyethylene coconut alkylamine, tertiary amine compounds such as tris (dimethylaminomethyl) phenol and their derivatives, 2-methylimidazole, 2-phenylimidazole, Imidazole compounds such as 2-phenyl-4-methylimidazole and derivatives thereof, organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, tris (4-methylphenyl) phosphine, diphenylphosphine, phenylphosphine, and the like Presence of compounds having intramolecular polarization formed by adding a compound having a π bond such as maleic anhydride, the above quinone compound, diazophenylmethane, and phenol resin to organic phosphine. And tetraphenylboron salts such as phosphorus compounds, tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, 2-ethyl-4-methylimidazole tetraphenylborate, N-methylmorpholine tetraphenylborate, and derivatives thereof. These may be used alone or in combination of two or more. Among them, polyoxyethylene coconut alkylamine is preferable in terms of toxicity.

The proportion of the curing accelerator is not particularly limited as long as the curing acceleration effect is achieved, but 0.01 to 10 parts by mass is 100 parts by mass with respect to 100 parts by mass of the hot melt adhesive. preferable. If it is less than 0.01 parts by mass, the heat resistance is lowered. If it exceeds 10 parts by mass, stickiness will appear.

In addition, the (F) curing accelerator used in the present invention is preferably added to the surface of the hot melt composition coating material after being diluted with water or a good solvent to an appropriate concentration in order to apply a necessary amount in a small amount. If there is another adherend, a curing accelerator may be applied to the surface of the adherend and then bonded to the hot melt composition coating. Or you may apply | coat a hardening accelerator beforehand to the film etc. which apply | coat a hot-melt composition, and may apply a hot-melt-adhesive agent after that. The proportion of the curing accelerator is not particularly limited as long as the curing acceleration effect is achieved, but 0.01 to 10 parts by mass is 100 parts by mass with respect to 100 parts by mass of the hot melt adhesive. preferable. If it is less than 0.01 parts by mass, the heat resistance is lowered. If it exceeds 10 parts by mass, stickiness will appear.

It is preferable that the curing accelerator applied to the surface diffuses into the adhesive and the curing reaction proceeds to the bottom. The degree of cure can be measured, for example, by reducing the intensity of the C = O characteristic infrared absorption band of maleic anhydride. Further, it is most preferable that the degree of curing at the bottom is advanced so that, for example, the strength of the C = O characteristic infrared absorption band of maleic anhydride is 1/10 or less before curing. It is preferably at least one third or less.

  In addition, the rubber-based curable hot-melt adhesive composition in the present invention is characterized in that it can be used for pressure-sensitive adhesive tapes and the like that require heat resistance because it has adhesiveness even after curing.

Preparation of the hot melt adhesive composition in the present invention is preferably carried out in a melting dissolution tank such as a heating type melting stirring tank, preferably under a vacuum, in a nitrogen stream, at a normal temperature of 150 ° C. or more and 250 ° C. or less, by rotating the stirring blades, It is carried out by a method of melt-mixing each component in order, a method of melt-mixing by heating with a twin kneading blade of a kneader, a method of melt-mixing by a screw of a single or twin screw extruder, and the like.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, this is merely an example, and the present invention is not limited thereto unless it exceeds the gist. In addition, unless otherwise indicated, the part and% in an Example are a mass part and mass%.

  The curability and tackiness of the rubber curable hot melt adhesive composition were evaluated by the following tests.

(1) The heat resistance of the cured hot melt adhesive composition was evaluated by a SAFT (shear bond breaking temperature) test. A test piece was prepared by applying a curing accelerator to the surface of a hot melt adhesive applied to a PET film at a thickness of 30 μm and curing the coating. The test conditions are the same as the practical conditions for melting the test piece 25 mm wide and 25 mm long on the SUS plate and then allowing it to cool, and then increasing the temperature at a rate of 2 ° C / 5 minutes with a 100 g load. And measure the drop temperature. The measurement was performed from room temperature to 180 ° C.
(2) By measuring the infrared absorption of the hot-melt adhesive, change in the peak near 1780 cm ⁻¹ due to C═O of the acid anhydride, CO of COO obtained by reaction of the acid anhydride and epoxy = change in peak around 1750 cm ^-1 due to O, or acid anhydride ring opened carbonium ion COO by curing accelerator ^- to investigate the change in the peak around 1710 cm ^-1 due to the C = O Evaluation was made by infrared absorption measurement before and after curing.
(3) When a curing accelerator is applied to the surface of the hot melt adhesive composition, in order to measure the inclination of the degree of curing with respect to the depth direction from the surface after curing, a microtome or the like is used to measure the depth direction from the surface. Then, the microscopic ATR measurement of the obtained cross section was performed, and the degree of cure in the depth direction was examined using the same evaluation method as in (2).
(4) The tackiness of the hot melt adhesive composition was evaluated by measuring 180 ° peel force. A test piece was prepared by applying a curing accelerator to the surface of a hot melt adhesive applied to a PET film at a thickness of 30 μm and curing the coating. The test condition is that the above-mentioned test piece is cut to a width of 25 mm and attached to a SUS plate, and a 2 kg load roll is reciprocated once on the attached part and pressed. The test piece was measured for 180 ° peel force in an atmosphere of 23 ° C. and 80 ° C. to evaluate the tackiness.

Example 1
(A-1) Maleic anhydride-modified SEBS (Clayton Polymer Japan, Inc., trade name: Kraton FG-1901X, maleic anhydride addition amount 1.7%, MFR 22.0 g / 10 min) 30 parts by mass, (B- 1) Epoxy resin (Japan Epoxy Resin Co., Ltd., trade name: Epicoat 825, Epoxy equivalent 172-178) 2.0 parts by mass, (C-1) Non-reactive block copolymer [Clayton Polymer Japan, Inc. trade name : Kraton G-1726] 5.0 parts by mass, (D-1) tackifying resin [Yasuhara Chemical Co., Ltd., trade name: YS Resin TO-105] 50 parts by mass, (E-1) Process oil (Idemitsu Kosan ( (Trade name: PW-32) 15 parts by mass and 0.5 parts by mass of an antioxidant were kneaded with a kneader to prepare a hot melt adhesive. (F-1) 2,4,6-tris (dimethylaminomethyl) phenol (hereinafter referred to as DMP-30) (trade name: Ancamine K-54 manufactured by Air Products Japan Co., Ltd.) was used as a curing accelerator.

In order to perform the SAFT test of the evaluation method, the hot melt adhesive composition was applied to a PET film at 30 μm, the curing accelerator DMP-30 (F-1) was applied at 0.5 g / m ² and 50 ° C. The test piece was cured and cured for 1 day. In addition, in order to compare before and after curing by infrared absorption measurement, the hot melt adhesive composition was applied to a release PET film at 30 μm, cured in the same manner, and cured hot melt adhesive composition. Was peeled off from the release film to prepare a test piece, and infrared absorption measurement was performed by transmission. The results are shown in Table 1. Further, the hot melt adhesive composition was molded to have a surface of 10 mm × 10 mm × thickness of 300 to 350 μm, and the surface was coated with 0.5 g / m ^{2 of} a curing accelerator, and cured at 50 ° C. for 3 days. Then, it was cut from the surface in the depth direction using a microtome, and the microscopic infrared absorption measurement was performed every 20 μm from the surface to the depth direction, and the inclination of the curing degree was examined. The results are shown in Table 2.

Examples 2-4
(A-1) Maleic anhydride-modified SEBS (Clayton Polymer Japan, Inc., trade name: Kraton FG-1901X, maleic anhydride addition amount 1.7%, MFR 22.0 g / 10 min) 30 parts by mass, (B- 1) Epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 825, epoxy equivalent 172-178) 0.5, 1.0, 1.5 parts by mass, (C-1) non-reactive block copolymer [Clayton Polymer Japan Co., Ltd. trade name: Clayton G-1726] 5 parts by mass, (D-1) Tackifying resin [Yasuhara Chemical Co., Ltd., trade name: YS Resin TO-105] 50 parts by mass, (E-1) Process oil (trade name: PW-32, manufactured by Idemitsu Kosan Co., Ltd.) 15 parts by mass and 0.5 parts by mass of antioxidant are kneaded with a kneader to adjust the hot melt adhesive. . As a curing accelerator, DMP-30 (F-1) (trade name: DMP-30 manufactured by Air Products Japan Co., Ltd.) was used. A test piece was prepared in the same manner as in Example 1.

Comparative Example 1
It was produced in the same manner as in Example 1 except that the curing accelerator of Example 1 was not used.

Example 5
In order to verify the application amount of the curing accelerator, a test piece was prepared by applying a curing accelerator of 0.05 g / m ² on 30 μm of a hot melt adhesive, curing it at 50 ° C. for 1 day, and curing it. The test method shown above was used.

Examples 6-11
In order to verify the effect of the curing accelerator, 0.5 g / m ^{2 of} various curing accelerators were applied to the surface of the hot melt adhesive composition coated to a thickness of 30 μm and cured at 50 ° C. for 1 day. Was used as a test piece. The test method shown above was used.

Examples 12 and 13
In order to verify the tackiness after curing, only the ratio of (A-1) maleic anhydride-modified SEBS and (C) non-reactive block copolymer in Example 1 was changed. In Example 1, Kraton FG-1901X / Clayton G-1726 = 30/5. Furthermore, in order to improve the adhesiveness after curing, the ratio was changed to Kraton FG-1901X / Clayton G-1726 = 25/10, 20/15, and the same production as in Example 1 was performed.

In order to compare the tackiness of Examples 1, 12, and 13, the 180 ° peel force of the above evaluation method was measured. A test piece was prepared by applying 0.5 g / m ² of a curing accelerator DMP-30 (F-1) to the surface of a hot melt adhesive composition applied to a PET film at a thickness of 30 μm and curing at 50 ° C. for 1 day. Using. The test condition is that the above-mentioned test piece is cut to a width of 25 mm and attached to a SUS plate, and a 2 kg load roll is reciprocated once on the attachment part and is attached by pressure bonding. The test piece was measured for 180 ° peel force at a tensile rate of 300 mm / min in an atmosphere of 23 ° C. and 80 ° C. to evaluate the tackiness. The results are shown in Table 4. In addition, the SAFT test was also performed as in Example 1, and the results are shown in Table 4.

Example 14
In order to confirm whether or not the tackiness after curing was improved by adding the non-reactive block copolymer, the ratio (30/5) of Kraton FG-1901X / Clayton G-1726 of Example 1 was (35 / 0) and the same production as in Example 1 was carried out.

In Examples 1 to 14 of the present invention, an inclination was observed in the degree of curing caused by the degree of progress of the crosslinking reaction with a curing accelerator other than moisture, and compared to Comparative Example 1, the heat resistance was improved as shown in Tables 1 to 3. It was excellent. Moreover, it was stored after manufacture, and an attaching process was possible when necessary, and the operation was also simple. There was no use of harmful solvents and the environment was excellent.

  In addition, Examples 1, 12, and 13 were given heat resistance by replacing a part of maleic anhydride-modified SEBS with a non-reactive block copolymer (Clayton G-1726) as shown in Table 4 in comparison with Example 14. However, the adhesiveness at high temperature (80 ° C.) could be improved.

The present invention is a rubber-based curable hot-melt adhesive composition having high cohesive strength and tackiness, and can be used without solvent during coating, and thus has a great advantage of being environmentally friendly. is doing.

Claims (5)

Anhydride styrene block copolymer component (A) 10 to 40 wt% imparted with an epoxy resin component (B) 0.1 to 20 mass%, non-reactive block copolymer component (C) 1 to 40 wt%, the tackifying resin component (D) 30 to 70 wt%, the hot melt adhesive composition containing 5 to 30 wt% plasticizing oil component (E) (wherein, (a) + (B) + (C) + (D) A rubber-based curable hot-melt adhesive composition obtained by adding a curing accelerator (F) to the surface of a hot melt composition coated product (+ (E) = 100% by mass ) and reacting from the surface.   (A) Styrene / butadiene / styrene block copolymer (hereinafter referred to as “SBS”), styrene / isoprene / styrene block copolymer (hereinafter referred to as “SIS”), styrene / ethylene containing 0.5 to 5% by mass of an acid anhydride The rubber-based curable hot melt adhesive according to claim 1, which is at least one selected from a butylene / styrene block copolymer (hereinafter referred to as “SEBS”) and a styrene / ethylene propylene / styrene block copolymer (hereinafter referred to as “SEPS”). Composition.   The rubber-based curable hot-melt adhesive composition according to claim 1 or 2, wherein the component (B) is an epoxy resin containing 2 to 10 epoxy groups in the molecule.   The curing accelerator (F) accelerates the reaction between the acid anhydride and the epoxy, and is selected from tertiary amines and salts thereof, imidazoles and salts thereof, organic phosphine compounds and salts thereof, and organic acid metal salts. The rubber-based curable hot-melt adhesive composition according to claim 1, 2 or 3, which is at least one kind of curing accelerator. Rubber-based curable hot-melt adhesive according to claim 1 or 2 or 3 or 4 amount of the curing accelerator (F) is 0.05 to 5 parts by weight with respect to the hot melt adhesive composition 100 parts by weight Agent composition.