Hot-melt adhesive composition

Abstract

To provide a hot-melt adhesive composition which exhibits a low reactivation temperature, and superior thermal resistance and workability.SOLUTION: The hot-melt adhesive composition comprises: polyolefin component A with a melting point of 120 to 150°C and a melting enthalpy of 60 to 100 J / g; polyolefin component B having a melting point of 80 to 120°C and a melting enthalpy of less than 60 J / g, polymerized by a single-site catalyst; and tackifying resin component C having a softening point in the range of 130 to 150°C.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hot melt adhesive composition. [Background technology]

[0002] In recent years, the technique of joining components used in assembly with hot melt adhesive compositions has been widely used in various industrial fields such as the automotive field, the construction field, the electrical and electronic field, etc. For example, in the automotive field, hot melt adhesive compositions are used to join plastics, metals, glass, etc. in various applications such as doors, roofs, lamps, seats, glove boxes, and floors.

[0003] When these automotive components are joined with a hot melt adhesive composition, the components are prone to high temperatures, requiring adhesive performance (heat resistance) in high-temperature environments. To overcome these challenges, polyamide-based hot melt adhesives and urethane-based moisture-curing hot melt adhesives are used as hot melt adhesive compositions. However, polyamide-based hot melt adhesives are highly hygroscopic, and therefore foam and poor application suitability occur depending on the storage and use environment. This necessitates the use of melting equipment capable of dry air purging. Furthermore, urethane-based hot melt adhesives, which form crosslinked structures through moisture curing reactions, exhibit excellent heat resistance and adhesive properties after reactive curing. However, these adhesives have challenges, such as the need to use melting equipment capable of dry air or nitrogen gas purging during use, the inability to fully demonstrate performance due to excessive reaction acceleration in high-temperature, high-humidity environments, and the need for several days for adhesive properties to be achieved through reactive curing. Therefore, polyolefin-based hot melt adhesive compositions, which are highly stable during use and storage and do not require reactive curing, are promising.

[0004] Furthermore, since automotive applications often use components with low heat distortion temperatures, hot melt adhesive compositions with a low reactivation temperature, which is the temperature at which they can be bonded, and a low melt viscosity, which is an indicator of workability, are preferred. Various proposals have been made, such as Patent No. 6243236 (Patent Document 1) and Patent No. 6810898 (Patent Document 2), but they have not been able to fully satisfy the performance required by users. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6243236 [Patent Document 2] Patent No. 6810898 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention was completed under such background technology, and its object is to provide a polyolefin-based hot melt adhesive composition that has excellent heat resistance to various adherends, a low reactivation temperature, and excellent workability. [Means for solving the problem]

[0007] As a result of intensive research conducted by the present inventors to solve the problems in the prior art, they discovered that it is effective to use a specific ratio of polyolefin component A and polyolefin component B, each having a different specific melting point and melting enthalpy, and to blend a specific ratio of a tackifier resin component having a specific softening point, and thus completed the present invention.

[0008] Thus, according to the present invention, the following inventions are provided. (1) A hot melt adhesive composition comprising 5 to 40% by weight of a polyolefin component A having a melting point of 120 to 150°C and a melting enthalpy of 60 to 100 J / g, 10 to 45% by weight of a polyolefin component B having a melting point of 80 to 120°C and a melting enthalpy of less than 60 J / g, polymerized using a single-site catalyst, and further comprising 20 to 50% by weight of a tackifier resin component C having a softening point of 130 to 150°C. (2) The hot melt adhesive composition according to (1), wherein the polyolefin component A is a homopolymer of propylene or a copolymer of propylene and an α-olefin having 2 to 20 carbon atoms. (3) The hot melt adhesive composition according to (1) or (2), wherein the polyolefin component B is a propylene homopolymer polymerized using a single-site catalyst or a copolymer of propylene and an α-olefin having 2 to 20 carbon atoms. (4) The hot melt adhesive composition according to any one of (1) to (3), wherein the tackifying resin component C is a hydrogenated tackifying resin. (5) The hot melt adhesive composition according to any one of (1) to (4), further comprising one or more of an antioxidant, an ultraviolet stabilizer, an ultraviolet absorber, a metal deactivator, an inorganic filler, a silane coupling agent, a pigment, and a dye in an amount of 5% by weight or less based on the hot melt adhesive composition. (6) A hot melt adhesive composition according to any one of (1) to (5), having a melt viscosity at 180°C of 300,000 mPa·s or less. (7) The hot melt adhesive composition according to any one of (1) to (5) above, which is used for automobile parts, building parts, or electrical parts. [Effects of the Invention]

[0009] According to the present invention, by using polyolefin components each having a different specific melting point and melting enthalpy in combination with a tackifier resin component having a specific softening point, it is possible to provide a hot melt adhesive composition that is excellent in workability, has excellent heat resistance against various adherends, and has a low reactivation temperature. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the present invention will be described in detail with reference to an embodiment thereof, but the present invention is not limited to this embodiment. In addition, the components in the following embodiments include those that can be easily imagined by those skilled in the art or those that are substantially the same.

[0011] The hot melt adhesive composition of the present invention is a composition used as an adhesive for bonding adherends or as an adhesive component of such an adhesive, and contains as essential components: a polyolefin component A having a melting point of 120 to 150°C and a melting enthalpy of 60 to 100 J / g; a polyolefin component B having a melting point of 80 to 120°C and a melting enthalpy of less than 60 J / g, which is polymerized using a single-site catalyst; and a tackifier resin component C having a softening point of 130 to 150°C.

[0012] <Polyolefin component A> In the present invention, polyolefin component A has a melting point of 120 to 150°C and a melting enthalpy of 60 to 100 J / g. Polyolefin component A is a component suitable for heat resistance, and the melting point and melting enthalpy are important requirements. If the melting point and melting enthalpy are below this range, the hot melt adhesive composition will lack heat resistance. Conversely, if they are above this range, the heat resistance will be more favorable, but good adhesion to the adherend and the reactivation temperature cannot be maintained low, raising concerns about deformation of the adherend during application. A preferred melting point is 125 to 150°C. Furthermore, a preferred melting enthalpy is 65 to 90 J / g, more preferably 65 to 85 J / g.

[0013] The amount of polyolefin component A blended is 5 to 40% by weight, preferably 5 to 30% by weight, based on 100% by weight of the hot melt adhesive composition. If the amount of polyolefin component A blended is below this range, the heat resistance of the hot melt adhesive composition will decrease, while if it is above this range, the hot melt adhesive composition will have favorable heat resistance, but on the other hand, the adhesion to the adherend will be significantly reduced and the reactivation temperature will not be able to be maintained low.

[0014] In the present invention, "polyolefin" refers to a polymer containing an olefin as a monomer, and may be an olefin homopolymer or a copolymer copolymerized with an olefin and a compound copolymerizable with the olefin. In the present invention, the polyolefin copolymer is preferably an olefin copolymer containing 50% by weight or more, preferably 60% by weight or more, of an olefin and less than 50% by weight, preferably less than 40% by weight, of a compound copolymerizable with the olefin. The olefin used in polyolefin component A is preferably an α-olefin having 2 to 20 carbon atoms. Examples of α-olefins having 2 to 20 carbon atoms include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, etc., as well as combinations thereof. These may be used alone or in combination. More preferred polyolefins for polyolefin component A are propylene homopolymers or copolymers of propylene and an α-olefin having 2 to 20 carbon atoms, and most preferred polyolefins are propylene homopolymers or copolymers of propylene and an α-olefin having 2 to 8 carbon atoms.

[0015] The polyolefin component A can be obtained by polymerizing a monomer in the presence of a polymerization catalyst such as a Ziegler-Natta catalyst, which is a type of multi-site catalyst, or a metallocene catalyst, which is a type of single-site catalyst.

[0016] Specific examples of polyolefin component A include Prime Polypro F392RA (melting point: 144°C, fusion enthalpy: 70 J / g, manufactured by Prime Polymer Co., Ltd.), Prime Polypro F724NPC (melting point: 150°C, fusion enthalpy: 78 J / g, manufactured by Prime Polymer Co., Ltd.), and WINTEC WSX03 (melting point: 126°C, fusion enthalpy: 70 J / g, manufactured by Japan Polypropylene Corporation).

[0017] The polyolefin component A may be a single component, or may be a combination of two or more components as required.

[0018] <Polyolefin component B> In the present invention, polyolefin component B has a melting point of 80 to 120°C and a melting enthalpy of less than 60 J / g, and is polymerized using a single-site catalyst. In the present invention, polyolefin component B is a component suitable for the reactivation temperature, and the melting point and melting enthalpy are important requirements. By blending polyolefin component B, which has a low melting point and low crystallinity, with polyolefin component A, it is possible to maintain a low reactivation temperature while ensuring adhesive performance. If the melting point and melting enthalpy of polyolefin component B are below this range, the heat resistance of the hot melt adhesive composition will decrease. Conversely, if they are above this range, it will be impossible to achieve good adhesion to the adherend or maintain a low reactivation temperature. The preferred melting point is 80 to 110°C, more preferably 80 to 105°C. The preferred melting enthalpy is 55 J / g or less.

[0019] Polyolefin component B must be synthesized using a single-site catalyst. Synthesis using a single-site catalyst is characterized by the presence of only one active site, making it possible to selectively prepare polymers with specific physical properties. The polymers obtained using a metallocene catalyst, a type of single-site catalyst, are uniform polymers with narrow molecular weight and composition distributions, and are effective in balancing reactivation temperature and heat resistance.

[0020] The amount of polyolefin component B is 10 to 45 wt %, preferably 10 to 40 wt %, based on 100 wt % of the hot melt adhesive composition. If the amount of polyolefin component B is below this range, the hot melt adhesive composition will not be able to maintain good adhesion to the adherend or a low reactivation temperature. Conversely, if the amount is above this range, heat resistance will decrease.

[0021] The olefin used in polyolefin component B is preferably a combination of α-olefins having 2 to 20 carbon atoms, and these may be used alone or in combination of two or more. The polyolefin more preferred for polyolefin component B is a propylene homopolymer or a copolymer in which propylene is polymerized with an α-olefin having 2 to 20 carbon atoms, and the most preferred polyolefin is a propylene homopolymer or a copolymer in which propylene is polymerized with an α-olefin having 2 to 8 carbon atoms.

[0022] Specific examples of polyolefin component B include LICOCENE Examples include PP2602 (melting point: 84°C, fusion enthalpy: 40 J / g, manufactured by Clariant), LICOCENE PP3602 (melting point: 102°C, fusion enthalpy: 55 J / g, manufactured by Clariant), Vistamaxx 8380 (melting point: 97°C, fusion enthalpy: 20 J / g, manufactured by ExxonMobil), Vistamaxx 8780 (melting point: 91°C, fusion enthalpy: 21 J / g, manufactured by ExxonMobil), and Vistamaxx 8880 (melting point: 98°C, fusion enthalpy: 35 J / g, manufactured by ExxonMobil).

[0023] The polyolefin component B may be a single component, or may be a combination of two or more components as required.

[0024] <Tackifying resin component C> In the present invention, tackifying resin component C is used as a component that imparts adhesion, improves heat resistance, and reduces melt viscosity to improve workability. The "tackifying resin" used in the present invention is one that is commonly used in hot melt adhesive compositions, and is not particularly limited as long as it can produce the hot melt adhesive composition desired by the present invention. The softening point of tackifying resin component C is preferably 130 to 150°C, and more preferably 130 to 145°C. If the softening point exceeds this range, good adhesion to the adherend and the reactivation temperature cannot be maintained, and conversely, if the softening point is below this range, heat resistance will decrease.

[0025] The amount of tackifier resin component C is 20 to 50 wt %, more preferably 25 to 45 wt %, based on 100 wt % of the hot melt adhesive composition. If the amount of tackifier resin component C is below this range, it will be difficult to maintain good adhesion to the adherend or the reactivation temperature, and if it is above this range, heat resistance will decrease.

[0026] Examples of tackifying resins used in tackifying resin component C include C5 petroleum resins, C9 petroleum resins, C5C9 petroleum resins, dicyclopentadiene petroleum resins, terpene resins, and rosin resins, as well as hydrogenated tackifying resins such as partially hydrogenated resins and / or fully hydrogenated resins obtained by adding hydrogen to these tackifying resins. Adding hydrogen to the tackifying resin reduces the unsaturated bonds in the tackifying resin, which has the effect of improving compatibility, weather resistance, color, odor, etc.

[0027] In the present invention, it is more preferable to use a partially hydrogenated resin and / or a fully hydrogenated resin from the viewpoint of compatibility.

[0028] Specific examples of the tackifying resin component C include Eastotac H-130E (softening point: 130°C, manufactured by Eastman), Eastotac H-142R (softening point: 142°C, manufactured by Eastman), Imave P-140 (softening point: 140°C, manufactured by IFCS), ESCOREZ 5340 (softening point: 140°C, manufactured by ExxonMobil), Alcon P-140 (softening point: 140°C, manufactured by Arakawa Chemical Industries, Ltd.), Alcon M-135 (softening point: 135°C, manufactured by Arakawa Chemical Industries, Ltd.), T-REZ OP501 (softening point: 138°C, manufactured by ENEOS), SUKOREZ SU-130 (softening point: 130°C, manufactured by KOLON), and SUKOREZ Examples include SU230 (softening point: 130°C, manufactured by KOLON), SUKOREZ SU140 (softening point: 140°C, manufactured by KOLON), and SUKOREZ SU640 (softening point: 138°C, manufactured by KOLON).

[0029] The tackifying resin component C may be a single resin, or may be a mixture of two or more resins as required.

[0030] <Other polyolefin components> In the present invention, other polyolefin component D can be used as a modifier. Other polyolefin component D refers to the polyolefin defined in paragraph

[0014] of this specification, meaning a polymer containing an olefin as a monomer. It may be an olefin homopolymer or a copolymer copolymerized with an olefin and a copolymerizable compound. These are commonly used in hot melt adhesive compositions and are not particularly limited as long as they do not fall under the category of polyolefin component A or polyolefin component B. It is preferable that other polyolefin component D has a melt flow rate of 5.0 or higher. The amount of other polyolefin component D is 15 wt% or less, preferably 12 wt% or less, and more preferably 10 wt% based on 100 wt% of the hot melt adhesive composition.

[0031] Other specific examples of polyolefin component D include the REXtac series (manufactured by REXtac), the VESTPLAST series (manufactured by Evonik), the Tafmer series (manufactured by Mitsui Chemicals, Inc.), the Eastflex series (manufactured by Eastman), the LICOCENE series (manufactured by Clariant), the Vistamaxx series (manufactured by ExxonMobil), the Viscol series (manufactured by Sanyo Chemical Industries, Ltd.), the Umex series (manufactured by Sanyo Chemical Industries, Ltd.), and the Micropro series (Sumitomo Pharma Food & Chemical).

[0032] <Other compounding agents> In the present invention, in addition to the above-mentioned components A to C and component D, one or more compounding agents commonly used in the technical field of hot melt adhesive compositions, such as antioxidants, ultraviolet absorbers, metal deactivators, fillers, silane coupling agents, pigments, dyes, antistatic agents, flame retardants, stabilizers such as ultraviolet stabilizers, solvents, and antifoaming agents, may be compounded as needed.

[0033] Examples of antioxidants include naphthylamines, p-phenylenediamines, quinolines, phenols, hindered phenols, hindered amines, phosphites, thioethers, and hydroxylamines, with hindered phenol antioxidants being preferred. The amount of antioxidant to be added is 0.1 to 5 wt %, preferably 0.5 to 4 wt %, and more preferably 1 to 3 wt %, based on 100 wt % of the hot melt adhesive composition, from the viewpoints of the antioxidant effect and thermal stability of the composition.

[0034] Examples of UV absorbers include benzotriazoles, triazines, benzophenones, and cyanoacrylates. From the viewpoint of weather resistance of the composition, the amount of UV absorber to be added is 0.1 to 5 wt %, preferably 0.5 to 4 wt %, and more preferably 1 to 3 wt % based on 100 wt % of the hot melt adhesive composition. Fillers that have been conventionally used can be used, including inorganic or organic fillers of various shapes. Adding a filler can strengthen the cured product and provide excellent adhesion to, for example, mortar and metals. Examples of inorganic fillers include calcium carbonate, zinc oxide, glass beads, titanium oxide, alumina, carbon black, clay, ferrite, talc, mica powder, aerosil, silica, and inorganic fibers and inorganic foams such as glass fibers. Examples of organic fillers include powders of thermosetting resins such as epoxy resins, carbon fibers, synthetic fibers, and synthetic pulp.

[0035] Examples of silane coupling agents include trimethoxyvinylsilane and y-glycidoxypropyltrimethoxysilane, and their incorporation improves adhesion to wet surfaces. Examples of pigments include inorganic pigments such as titanium oxide, zinc oxide, ultramarine, red iron oxide, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride, and sulfate; and organic pigments such as Neo Zabon Black RE, Neo Black RE, Orasol Black CN, and Orasol Black Ba (all manufactured by Ciba-Geigy), and Spiro Blue 2BH (manufactured by Hodogaya Chemical Co., Ltd.), which can be used in appropriate combinations as needed.

[0036] Dyes such as black, yellow, red, blue, and brown dyes are used depending on the desired color of the product. Antistatic agents include hydrophilic compounds such as quaternary ammonium salts, polyglycols, and ethylene oxide derivatives. Flame retardants include chloroalkyl phosphates, dimethyl methyl phosphates, bromine-phosphorus compounds, ammonium polyphosphates, neopentyl bromide polyethers, and brominated polyethers. Stabilizers include fatty acid silyl esters and fatty acid amide trimethylsilyl compounds. Antifoaming agents include calcium oxide, magnesium oxide, and molecular sieves.

[0037] The method for producing the hot melt adhesive composition of the present invention is not particularly limited, and it can be produced by a conventionally known method. For example, each of the polyolefin components A to C, along with any other components that are optionally blended, can be melted. Specifically, the above components are charged into a melt-mixing tank equipped with a stirrer and heated and mixed to produce the hot melt adhesive composition. The charging procedure is not particularly limited, and may include a method in which all components are charged at once and heat-melted, a method in which the components are charged stepwise and heat-melted, or a method in which polyolefin components A to C and a portion of the other components are preliminarily heat-melted, and then the remaining components are charged and heat-melted. The hot melt adhesive composition thus obtained can be molded into, for example, pellets or pearls and packaged in paper bags or cardboard, or filled into release boxes, pails, or drums for storage.

[0038] The uses of the hot melt adhesive composition of the present invention are not particularly limited, and it can be used for applications such as automobiles and vehicles (bullet trains and electric trains), electrical appliances, building materials, woodworking, bookbinding and packaging. Automotive-related applications include bonding of automobile parts, such as lamps, ceilings, doors, seats, mats, carpets, trim, pillars, padding, glove boxes, console boxes, etc. Specifically, it can be suitably used for bonding vehicle interior parts, particularly adherends such as polypropylene, ABS, vinyl chloride coverings, and urethane coverings. Electrical applications include refrigerators, washing machines, televisions, massage chairs, and audio equipment. Furthermore, applications related to building materials and woodworking include bonding of doors, access floors, multi-layer floors, furniture assembly, edge bonding, profile wrapping, etc., at construction sites and in the factory production of building materials (building components). For example, when one or both of the adherends to be bonded, such as polypropylene and ABS used in automobiles, and polystyrene and PET used in electrical appliances, are made of resins with a melting point of about 100 to 150°C, there is a concern that the adherends may be deformed when applied at temperatures of 160 to 200°C, which is the temperature at which a typical hot melt adhesive composition is used. Therefore, a low reactivation temperature is required. Furthermore, in these applications, adhesive performance in high-temperature environments of 80 to 100°C is required, and therefore the hot melt adhesive composition of the present invention can be suitably used.

[0039] <Hot melt adhesive> The hot melt adhesive composition of the present invention can be applied by heating and melting it, and exhibits adhesive strength by cooling and solidifying it.

[0040] The hot melt adhesive composition of the present invention has a melt viscosity at 180°C of 300,000 mPa·s or less, particularly 100,000 mPa·s or less, and more preferably 50,000 mPa·s or less.

[0041] The hot melt adhesive composition of the present invention is preferably reactivatable at 120°C and has a heat resistance of 80°C or higher.

[0042] The method of using the hot melt adhesive composition of the present invention is not particularly limited, and may be carried out in a conventional manner. For example, when using the hot melt adhesive composition to bond interior materials for a vehicle, the method may be as follows.

[0043] The method for heating and melting the hot melt adhesive composition and applying it is not particularly limited, and any conventionally known method for applying a hot melt adhesive composition can be used. Examples include a method in which a hot melt adhesive composition that has been heated and melted using a hot melt applicator or hot melt coater is applied to an adherend. The hot melt adhesive composition is typically applied to the surface of a member to be bonded, either automatically or manually, using a heating application device known as an applicator. The heating application device is a device capable of sucking up a fixed amount of molten hot melt adhesive composition using a gear pump or the like, and is used by heating the composition appropriately depending on the softening point of the hot melt adhesive composition. The application shape of the hot melt adhesive composition is not particularly limited, but it is typically applied by heating to the member to be bonded. The member to which the hot melt adhesive composition has been applied is then brought into contact with another member and mechanically fastened to form a bonding surface.

[0044] In addition to the method of applying the hot melt adhesive by heating using a hot melt applicator or a hot melt coater, other methods include immersing the adherend in a hot melt adhesive composition that has been heated and melted, spraying the hot melt adhesive composition that has been heated and melted onto the surface of a component using an air gun or a pressurized gun, and extruding the hot melt adhesive composition that has been heated and melted onto the surface of a component using an extruder.

[0045] Hot melt adhesive compositions are liquefied in a heating and melting device and then dispensed in various forms for use. The application form is not particularly limited, and examples include spray, spiral, linear, and planar. The application form is selected depending on the takt time for bonding the surfaces together, the required performance, and the required application equipment.

[0046] The equipment used to heat, melt, and apply the hot melt adhesive composition must be heated to or above the softening point of the hot melt adhesive composition. If the equipment is set below the softening point, the hot melt adhesive composition will not melt and cannot be used. The set temperature in the present invention is not particularly limited, but is usually 100 to 240°C, preferably 120 to 200°C, and more preferably 140 to 180°C. If the set temperature exceeds 240°C, thermal degradation of the hot melt adhesive composition occurs, resulting in problems such as deterioration in color and generation of degraded products.

[0047] As described above, the hot melt adhesive composition of the present invention has excellent properties in terms of reactivation temperature, heat resistance, and workability. [Example]

[0048] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples, reference examples, and comparative examples, "parts" and "%" are by mass unless otherwise specified. The physical properties were evaluated as follows.

[0049] (1) Melting point and enthalpy of fusion: Measured using a differential scanning calorimeter (DSC: Shimadzu Corporation, Model: DSC60-Plus). The standard material used for the measurement was alumina, and the measurement was performed in a nitrogen environment at a heating rate of 10°C / min. (2) Melt viscosity: Measured at 180° C. using a Brookfield automatic viscometer (model: Brookfield DV-II+Pro). The spindle number of the automatic viscometer used for the measurement was No. 27, and the rotation speed was set to 2 to 10 rpm. (3) Reactivation Temperature: The hot melt adhesive composition was processed into a sheet measuring 25 mm x 25 mm x 0.4 mm and sandwiched between a polypropylene sheet (size: 100 mm x 25 mm x 0.2 mm, manufactured by Standard Test Piece Co., Ltd.) and a polypropylene plate (size: 100 mm x 25 mm x 3.0 mm, manufactured by Standard Test Piece Co., Ltd.). The hot melt adhesive composition was then reactivated and heat-sealed using a heat press machine (manufactured by Tester Sangyo Co., Ltd.) set at 80 to 150 °C in 10 °C increments. The heat-sealed test pieces were forcibly peeled at each temperature to confirm adhesion. Test pieces were also prepared by pressing using a heat press machine, as described below for (4) Heat Resistance and (3) Reactivation Temperature. The test pieces prepared by pressing at 150 °C were subjected to creep tests using a constant temperature tester (manufactured by Isuzu Motors, Ltd.). The test conditions were a test temperature of 80°C, a load direction of 90°, a load of 100g, and a test time of 24 hours. A peel distance of 1mm or less was rated as ◎, 1 to 10mm or less as ○, and more than 10mm as ×.

[0050] Example 1 As polyolefin component A, 20 parts of Prime Polypro F392RA(A)-1 (polypropylene, melting point: 144°C, melting enthalpy: 70 J / g, manufactured by Prime Polymer Co., Ltd.), 10 parts of WINTEC WSX03(A)-2 (ethylene-propylene copolymer, melting point: 126°C, melting enthalpy: 70 J / g, manufactured by Japan Polypropylene Corporation), 30 parts of Licocene PP3602(B)-2 (ethylene-propylene copolymer, melting point: 102°C, melting enthalpy: 55 J / g, manufactured by Clariant) as polyolefin component B, and Easttac as tackifying resin component C. A hot melt adhesive composition containing 10 parts of H-130E(C)-1 (aliphatic saturated hydrocarbon resin, softening point: 130°C, manufactured by Eastman Co.) and 30 parts of Alcon P-140(C)-2 (alicyclic saturated hydrocarbon resin, softening point: 140°C, manufactured by Arakawa Chemical Industries, Ltd.) was prepared by heating and melting the components. The resulting hot melt adhesive composition was measured for (2) melt viscosity, (3) reactivation temperature, and (4) heat resistance.

[0051] Examples 2 to 10 and Comparative Examples 1 to 11 Hot melt adhesive compositions were prepared in the same manner as in Example 1, except that the compositions and formulation amounts of polyolefin component A, component B, tackifying resin component C, and other polyolefin component D were changed as shown in Table 1, and the obtained hot melt adhesive compositions were evaluated in the same manner as in Example 1. The results are shown in Tables 1 to 4. (B)-1 LICOCENE PP2602 (ethylene-propylene copolymer, melting point: 84°C, enthalpy of fusion: 38 J / g, manufactured by Clariant) (C)-3 Alcon P-100 (alicyclic saturated hydrocarbon resin, softening point: 100°C, manufactured by Arakawa Chemical Industries, Ltd.) (D)-1 Tafmer PN2070 (propylene-olefin copolymer, melting point: 138°C, fusion enthalpy: 16 J / g, manufactured by Mitsui Chemicals, Inc.) (D)-2 VESTPLAST 708 (amorphous polyolefin, melting point 84°C, fusion enthalpy: 20 J / g, manufactured by Evonik) (D)-3 SunAllomer PM900A (polypropylene, melting point: 166°C, fusion enthalpy: 117 J / g, manufactured by SunAllomer Co., Ltd.) (D)-4 Ultrathene 710 (ethylene-vinyl acetate copolymer, melting point 71°C, fusion enthalpy: 35 J / g, manufactured by Tosoh Corporation) (D)-5 Viscol 660P (polypropylene wax, melting point 145°C, fusion enthalpy: 87 J / g, manufactured by Sanyo Chemical Industries, Ltd.)

[0052] [Table 1]

[0053] [Table 2]

[0054] [Table 3]

[0055] [Table 4] The results in Tables 1 to 4 show that the hot melt adhesive compositions of the present invention have a low reactivation temperature and are excellent in heat resistance and workability. When adhesives made from these hot melt adhesive compositions of the present invention were used to bond adherends that can actually be used, the adhesives had sufficient low-temperature sealing properties and heat resistance.

[0056] In contrast, when polyolefin component A was not included (Comparative Example 1), poor heat resistance was confirmed, and when the blending amount of polyolefin component A exceeded 40 wt% (Comparative Example 2), poor reactivation temperature was confirmed. Furthermore, when the blending amount of polyolefin component B exceeded 45 wt% (Comparative Example 3), poor heat resistance was confirmed. When tackifier resin component C was less than 20 wt% (Comparative Example 4), poor workability was confirmed, and when it exceeded 50 wt% (Comparative Example 5), poor reactivation temperature was confirmed, and when the softening point was less than 130°C (Comparative Example 6), poor heat resistance was also confirmed. When a polyolefin exceeding the melting point range of polyolefin component A was used (Comparative Example 7), excellent heat resistance was achieved, but poor reactivation temperature was confirmed. When other polyolefin component D polymerized using a multi-site catalyst without polyolefin component B was included (Comparative Example 8), poor heat resistance was confirmed. In addition, when the polyolefin component D was contained in an amount of more than 15% by weight (Comparative Examples 9 and 10), it was not possible to satisfy all of the requirements for workability, reactivation temperature, and heat resistance. Furthermore, it was confirmed that the formulation described in the examples of Patent Document 2 was inferior in reactivation temperature (Comparative Example 11). [Industrial Applicability]

[0057] The hot melt adhesive composition of the present invention has a low reactivation temperature and is excellent in heat resistance and workability, and is useful as a hot melt adhesive composition for applications such as vehicle parts, electrical appliances, and housing components that use polyolefin materials as adherends.

Claims

1. A hot melt adhesive composition comprising 5 to 40 wt % of a polyolefin component A having a melting point of 120 to 150°C and a melting enthalpy of 60 to 100 J / g, 10 to 45 wt % of a polyolefin component B having a melting point of 80 to 120°C and a melting enthalpy of less than 60 J / g, which is polymerized using a single-site catalyst, and further comprising 20 to 50 wt % of a tackifier resin component C having a softening point of 130 to 150°C.

2. 2. The hot melt adhesive composition according to claim 1, wherein the polyolefin component A is a homopolymer of propylene or a copolymer of propylene and an α-olefin having 2 to 20 carbon atoms.

3. 3. The hot melt adhesive composition according to claim 1, wherein the polyolefin component B is a propylene homopolymer polymerized using a single-site catalyst or a copolymer of propylene and an α-olefin having 2 to 20 carbon atoms.

4. 3. The hot melt adhesive composition according to claim 1, wherein the tackifying resin component C is a hydrogenated tackifying resin.

5. 3. The hot melt adhesive composition according to claim 1, further comprising 5% by weight or less of one or more of an antioxidant, an ultraviolet stabilizer, an ultraviolet absorber, a metal deactivator, an inorganic filler, a silane coupling agent, a pigment, and a dye.

6. 3. The hot melt adhesive composition according to claim 1, wherein the melt viscosity at 180°C is 300,000 mPa·s or less.

7. 3. The hot melt adhesive composition according to claim 1, which is used for automobile parts, building parts, or electrical parts.

Images