Resin composition and hot-melt adhesive

Abstract

To improve the adhesive strength of a resin.SOLUTION: A resin composition comprising chemically modified nanocellulose and an acid anhydride-modified polyolefin resin.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] In recent years, biomass materials have been attracting attention as an environmentally friendly and sustainable resource in order to realize a carbon-neutral society. Nanocellulose, a representative biomass material, is expected to be used as a reinforcing material for resins due to its lightweight and high strength properties. However, since cellulose is difficult to disperse in resins, efforts are being made to improve its dispersibility.

[0003] For example, Patent Document 1 discloses a method for producing a cellulose composite, with the aim of substantially dispersing cellulose in a resin, comprising: a mixing step of mixing cellulose having hydroxyl groups with a polymer having reactive groups capable of reacting with the hydroxyl groups and having a nonpolar molecular chain; and a step of bonding the hydroxyl groups with the reactive groups.

[0004] It has been reported that aqueous dispersions of cellulose nanocrystals form superstructured adhesive layers between solid surfaces during evaporation-induced self-assembly (C-EISA), resulting in remarkable anisotropic adhesive strength (Non-Patent Document 1), raising expectations for the use of cellulose nanocrystals as adhesives. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2021 / 075224 [Non-patent literature]

[0006] [Non-Patent Document 1] "Exploiting Supramolecular Interactions from Polymeric Colloids for Strong Anisotropic Adhesion between Solid Surfaces", Advanced Materials, 2020, Vol. 32, Issue 14, 1906886 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to improve the adhesive strength of resins. [Means for solving the problem]

[0008] Adhesion strength can be improved by combining acid anhydride-modified polyolefin resin with chemically modified nanocellulose.

[0009] The present invention includes the following embodiments. [1] Chemically modified nanocellulose, an acid anhydride-modified polyolefin resin; A resin composition comprising: [2] The resin composition according to [1], wherein the chemically modified nanocellulose has a carboxy group. [3] The resin composition according to [1] or [2], wherein the chemically modified nanocellulose is oxidized nanocellulose. [4] The resin composition according to any one of [1] to [3], wherein the chemically modified nanocellulose contains an oxide of a cellulose-based raw material with hypochlorous acid or a salt thereof, and is substantially free of N-oxyl compounds. [5] The resin composition according to any one of [1] to [4], wherein the chemically modified nanocellulose has a structure in which the hydroxyl groups at the second and third positions of the glucopyranose ring are oxidized and dicarboxyl groups are introduced. [6] The resin composition according to any one of [1] to [5], wherein the acid anhydride-modified polyolefin resin includes a maleic anhydride-modified polyolefin resin. [7] The resin composition according to any one of [1] to [6], wherein the acid anhydride-modified polyolefin resin contains a maleic anhydride-modified polypropylene resin. [8] The resin composition according to any one of [1] to [7], wherein the acid anhydride-modified polyolefin resin has a weight average molecular weight of 50,000 to 100,000. [9] The resin composition according to any one of [1] to [8], wherein the acid anhydride-modified polyolefin resin has an acid value of more than 0 mgKOH / g and not more than 50 mgKOH / g.

[10] The resin composition according to any one of [1] to [9], wherein the acid anhydride-modified polyolefin resin has a melting point of 50 to 120°C.

[11] At least some of the hydroxyl groups of the chemically modified nanocellulose; At least a portion of the carboxy groups of the acid anhydride-modified polyolefin resin; The resin composition according to any one of [1] to

[10] , wherein the following are bonded to each other to form an ester bond:

[12] The resin composition according to any one of [1] to

[11] , wherein the ratio of the peel strength of the resin composition to the peel strength of a control resin composition obtained by excluding the chemically modified nanocellulose from the resin composition is 1.3 or more.

[13] A cured product obtained by curing the resin composition according to any one of [1] to

[12] .

[14] An adhesive comprising the resin composition according to any one of [1] to

[12] .

[15]

[14] An adhesive layer containing the adhesive according to

[14] ; a substrate in contact with at least one surface of the adhesive layer; A laminate with an adhesive layer comprising:

[16] A hot melt adhesive comprising the resin composition according to any one of [1] to

[12] .

[17] The hot melt adhesive according to

[16] , which is in the form of a pellet, a stick, or a film.

[18]

[16] or

[17] . An application gun comprising the hot melt adhesive according to

[16] or

[17] . [Effects of the Invention]

[0010] The present invention can improve the adhesive strength of the resin. [Brief explanation of the drawings]

[0011] [Figure 1] Figure 1 shows the peel test results for aluminum foil bonded with a film formed from maleic anhydride-modified polypropylene resin and oxidized nanocellulose. [Figure 2] Figure 2 shows the results of a peel test of aluminum foil adhered with a film formed from maleic anhydride-modified polypropylene resin. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these and various modifications are possible without departing from the gist of the present invention.

[0013] <Resin composition> One embodiment of the present invention relates to a resin composition comprising chemically modified nanocellulose and an acid anhydride-modified polyolefin resin.

[0014] In the resin composition according to this embodiment, the adhesive strength can be improved by using a combination of chemically modified nanocellulose and an acid anhydride-modified polyolefin resin. In particular, the adhesive strength at the interface between the resin composition and the adherend can be improved. It is surprising that the presence of chemically modified nanocellulose results in such an improvement in adhesive strength.

[0015] The reason for the improved adhesive strength is presumed to be that the chemically modified nanocellulose has some effect on the acid anhydride-modified polyolefin resin and changes its properties, but the present invention is not limited by the above reasons.

[0016] [Peel strength] The peel strength of the resin composition according to this embodiment is preferably higher than the peel strength of a control resin composition obtained by omitting the chemically modified nanocellulose from the resin composition. The control resin composition is prepared from the same types and amounts of components as the resin composition according to this embodiment, except that the chemically modified nanocellulose is not used. "Peel strength" refers to the force required to peel two adherends.

[0017] The ratio of the peel strength of the resin composition according to this embodiment to the peel strength of the control resin composition (hereinafter referred to as "peel strength ratio") is preferably 1.3 or more, more preferably 1.5 or more, even more preferably 3 or more, still more preferably 4 or more, and particularly preferably 5 or more. Since a higher peel strength ratio is preferable, there is no particular upper limit, and it may be, for example, 40, 30, 20, or 10. The range of the peel strength ratio may be determined by appropriately combining the above-mentioned lower and upper limits. The range of the peel strength ratio may be, for example, 1.3 to 40, 1.5 to 40, 3 to 30, 4 to 20, or 5 to 10.

[0018] The peel strength of the resin composition according to this embodiment is preferably 3 N / mm or more, more preferably 4 N / mm or more, even more preferably 5 N / mm or more, and particularly preferably 6 N / mm or more. Since a higher peel strength is preferable, there is no particular upper limit, and it may be, for example, 40 N / mm, 30 N / mm, 20 N / mm, or 10 N / mm. The range of the peel strength may be determined by appropriately combining the above-mentioned lower and upper limits. The range of the peel strength may be, for example, 3 to 40 N / mm, 4 to 30 N / mm, 5 to 20 N / mm, or 6 to 10 N / mm.

[0019] The method for measuring the peel strength is as follows: A more specific measuring method is as described in the Examples below. (1) The solvent is evaporated from a solution of the resin composition (or a control resin composition) to obtain a film, which is then cut into a size of 5 cm x 2 cm. (2) Sandwich the film between two 5 cm x 5 cm pieces of aluminum foil (50 μm thick) so that the long side of the film is aligned with one side of the aluminum foil, and press it using a heat press at 140°C and 9 kPa for 90 seconds, then leave it to cool at room temperature for at least 15 hours. (3) The film is cut into a size of 1 cm x 5 cm so that the adhesive surface is 1 cm x 2 cm to obtain a test piece. (4) Using an autograph, perform a peel test on three test pieces at room temperature at 100 mm / min. The average of the measurement results for the three test pieces is taken as the peel strength.

[0020] [Join format] The chemically modified nanocellulose and the acid anhydride modified polyolefin resin may be bonded (grafted) to each other, or may exist separately.

[0021] All of the chemically modified nanocellulose may be bonded to the acid anhydride-modified polyolefin resin, or may be present separately from the acid anhydride-modified polyolefin resin. Only a portion of the chemically modified nanocellulose may be bonded to the acid anhydride-modified polyolefin resin.

[0022] All of the acid anhydride-modified polyolefin resin may be bonded to the chemically modified nanocellulose, or may be separated from the chemically modified nanocellulose. Only a portion of the acid anhydride-modified polyolefin resin may be bonded to the chemically modified nanocellulose.

[0023] The chemically modified nanocellulose and the acid anhydride-modified polyolefin resin are bonded, for example, by covalent bonding. Preferably, at least some of the hydroxyl groups of the chemically modified nanocellulose are bonded to at least some of the carboxyl groups (derived from the acid anhydride groups) of the acid anhydride-modified polyolefin resin to form ester bonds.

[0024] [Chemically modified nanocellulose] The resin composition according to this embodiment contains chemically modified nanocellulose.

[0025] "Chemically modified nanocellulose" in this specification refers to cellulose that has been chemically modified and nanosized. Chemically modified nanocellulose can be obtained, for example, by chemically modifying and nanoizing a cellulosic raw material. The order of chemical modification and nanoization is not particularly limited, but it is preferable to chemically modify the cellulosic raw material and then nanoize it. Nanoization tends to be easier when the cellulosic raw material is chemically modified first.

[0026] The amount of chemically modified nanocellulose is preferably 0.1 to 40 mass %, more preferably 0.5 to 30 mass %, and even more preferably 1 to 15 mass %, based on the mass of the resin contained in the resin composition.

[0027] As used herein, "chemical modification" refers to chemically changing a part of the cellulose structure. Examples of chemical modifications include oxidation modification, phosphorylation modification, and carboxymethylation modification.

[0028] In the oxidative modification, for example, a cellulose-based raw material is oxidized to introduce a carboxyl group into at least a part of the cellulose structure.

[0029] In phosphorylation modification, for example, a compound or a salt thereof containing a phosphate group on at least some of the hydroxyl groups of the glucose units constituting cellulose undergoes a dehydration reaction to form a phosphate ester, thereby introducing a phosphate group or a salt thereof.

[0030] In the carboxymethylation modification, for example, carboxymethyl groups are introduced by ether-bonding to at least some of the hydroxyl groups of the glucose units that constitute cellulose.

[0031] Although not particularly limited, the chemical modification is preferably oxidative modification, i.e., the chemically modified nanocellulose is preferably oxidized nanocellulose.

[0032] The oxidative modification can be carried out by reacting the cellulosic raw material with an oxidizing agent, such as hypochlorous acid or its salts, and N-oxyl compounds, such as 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO).

[0033] From the viewpoint of exerting excellent adhesive strength, it is preferable to use hypochlorous acid or its salt as the oxidizing agent. In other words, chemically modified nanocellulose is preferably produced by oxidizing a cellulosic raw material with hypochlorous acid or its salt (without using an N-oxyl compound) and nano-sizing the resulting oxidized cellulose.

[0034] The following description focuses on oxidation of cellulosic raw materials with hypochlorous acid or its salts, but chemically modified nanocellulose is not limited to nanocellulose oxidized with hypochlorous acid or its salts.

[0035] [Oxidized cellulose] Hereinafter, unless otherwise specified, "oxidized cellulose" refers to an oxidation product of a cellulose-based raw material with hypochlorous acid or a salt thereof before defibration.

[0036] Examples of hypochlorous acid or salts thereof include hypochlorous acid water, sodium hypochlorite, potassium hypochlorite, calcium hypochlorite, and ammonium hypochlorite.

[0037] The amount of hypochlorous acid or its salt used is not particularly limited, but it is preferable to use it so that the available chlorine concentration in the reaction system is 6 to 43 mass %. The available chlorine concentration may be a low concentration of 6 to 14 mass %, or a high concentration of 14 to 43 mass %.

[0038] The definition of the effective chlorine concentration of hypochlorous acid or a salt thereof is as described in WO 2022 / 009979.

[0039] The cellulosic raw material is not particularly limited as long as it is a material primarily composed of cellulose, and examples thereof include pulp, natural cellulose, and fine cellulose obtained by depolymerizing cellulose through mechanical processing. The cellulosic raw material preferably has a type I crystal structure. As the cellulosic raw material, commercially available products such as crystalline cellulose made from pulp can be used as is. Alternatively, unused biomass containing a large amount of cellulose components, such as soybean pulp refuse or soybean hulls, may also be used as the raw material. Furthermore, the cellulosic raw material may be pre-treated with an alkali of an appropriate concentration in order to facilitate the penetration of the oxidizing agent used into the raw pulp. The main component of plants is cellulose, and bundles of cellulose molecules are called cellulose microfibrils. The cellulose in cellulosic raw materials is also contained in the form of cellulose microfibrils.

[0040] (N-oxyl compounds) Preferably, oxidized cellulose is substantially free of N-oxyl compounds. By being substantially free of N-oxyl compounds, the impact on the environment and human body is sufficiently reduced, resulting in a high level of safety. Examples of N-oxyl compounds include 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO).

[0041] As used herein, "substantially free of N-oxyl compounds" means that no N-oxyl compounds are used in the production of oxidized cellulose, that the oxidized cellulose contains no N-oxyl compounds at all, or that the content of N-oxyl compounds is 2.0 ppm by mass or less, and preferably 1.0 ppm by mass or less, relative to the total amount of oxidized cellulose. In addition, when the content of N-oxyl compounds is, as an increase from the cellulosic raw material, preferably 2.0 mass ppm or less, more preferably 1.0 mass ppm or less, it is also considered to be "substantially free of N-oxyl compounds."

[0042] The content of N-oxyl compounds can be measured by known means, such as a method using a trace total nitrogen analyzer (for example, TN-2100H manufactured by Nitto Seiko Analytech Co., Ltd.).

[0043] (carboxyl group amount) The amount of carboxy groups in the oxidized cellulose is preferably 0.1 to 3.0 mmol / g, more preferably 0.2 to 2.0 mmol / g, even more preferably 0.3 to 1.5 mmol / g, particularly preferably 0.4 to 1.2 mmol / g, and most preferably 0.5 to 0.9 mmol / g.

[0044] The amount of carboxy groups in oxidized cellulose can be measured by the method described in WO 2022 / 009979.

[0045] The oxidized cellulose in this embodiment preferably has a structure in which at least two of the hydroxyl groups on the glucopyranose ring that constitutes the cellulose are oxidized, and more specifically, preferably has a structure in which the hydroxyl groups at the second and third positions on the glucopyranose ring are oxidized and dicarboxyl groups are introduced. Furthermore, it is preferable that the hydroxyl group at the sixth position on the glucopyranose ring is not oxidized and remains as a hydroxyl group. The position of the carboxyl group on the glucopyranose ring is determined by the solid 13 It can be analyzed by C-NMR spectroscopy.

[0046] Rayon has the same chemical structure as cellulose, and its oxide (rayon oxide) is water-soluble. 13 By C-NMR measurement, a carbon peak attributable to the carboxy group is observed at 165 to 185 ppm. In one embodiment of the oxidation of a cellulosic raw material with hypochlorous acid or its salt, two signals appear in this chemical shift range. Furthermore, by solution two-dimensional NMR measurement, it can be determined that the carboxy groups are introduced at the 2- and 3-positions.

[0047] Solid oxide of cellulosic raw materials with hypochlorous acid or its salts 13 In C-NMR, when the amount of carboxyl groups introduced is large, two signals appear at 165 to 185 ppm, and when the amount of carboxyl groups introduced is small, a very broad signal may appear. As can be seen from the results for oxidized rayon, the signals of the carboxyl group carbons introduced at the 2nd and 3rd positions are close to each other, and this is difficult to achieve with low-resolution solid state spectroscopy. 13 In C-NMR, the separation of the two signals is insufficient. Therefore, when the amount of carboxyl group introduced is small, a broad signal is observed. 13 In the C-NMR spectrum, the introduction of carboxy groups at the 2nd and 3rd positions can be confirmed by evaluating the broadening of the peaks appearing at 165 to 185 ppm.

[0048] That is, solid 13 A baseline is drawn around the peak in the range of 165 ppm to 185 ppm in the C-NMR spectrum to determine the overall area value, and then the area value is vertically divided at the peak top to determine the ratio of the two peak area values ​​(large area value / small area value). If the ratio of the peak area values ​​is 1.2 or more, the peak can be said to be broad. The presence or absence of the broad peak can be determined by the ratio of the length L of the baseline in the range of 165 ppm to 185 ppm to the length L' of the perpendicular line from the peak top to the baseline. That is, if the ratio L' / L is 0.1 or more, it can be determined that a broad peak is present. The ratio L' / L may be 0.2 or more, 0.3 or more, 0.4 or more, or even 0.5 or more. There is no particular upper limit to the ratio L' / L, but it is usually 3.0 or less, and may be 2.0 or less, or 1.0 or less.

[0049] The structure of the glucopyranose ring can also be determined by analysis according to the method described in Sustainable Chem. Eng. 2020, 8, 48, 17800-17806.

[0050] (Viscosity average degree of polymerization) The viscosity average degree of polymerization of the oxidized cellulose is preferably 30-500, more preferably 60-300, even more preferably 70-150, and particularly preferably 80-130.

[0051] The viscosity average degree of polymerization is the average degree of polymerization measured by a viscosity method. The viscosity average degree of polymerization can be measured by the method described in WO 2022 / 009979.

[0052] [Method of producing oxidized cellulose] Oxidized cellulose can be produced by oxidizing a cellulosic raw material with hypochlorous acid or a salt thereof. Specific production methods include those described in WO 2022 / 009979 and WO 2022 / 009980. Oxidized cellulose is also available commercially, such as Aronfibro (registered trademark) manufactured by Toagosei Co., Ltd.

[0053] [Nanocellulose] Hereinafter, unless otherwise specified, "nanocellulose" refers to an oxide of a cellulose-based raw material with hypochlorous acid or its salt, after defibration.

[0054] Nanocellulose is a general term for micronized cellulose, including microfine cellulose fibers, which are also called cellulose nanofibers (CNF).

[0055] Nanocellulose preferably has a carboxyl group. The carboxyl group may be in the H type (-COOH) or in the salt type. The type of salt is not particularly limited, but examples include alkali metal salts such as lithium salt, sodium salt, and potassium salt; alkaline earth metal salts such as calcium salt and barium salt; other metal salts such as magnesium salt and aluminum salt; ammonium salt; and organic amine salts.

[0056] The nanocellulose may be modified with a modifying group. The modifying group may be introduced to at least some of the hydroxyl groups of the nanocellulose via a covalent bond. The modifying group may be introduced to at least some of the carboxyl groups of the nanocellulose via an ionic bond.

[0057] Modifying groups introduced onto the hydroxyl groups of nanocellulose include, for example, groups derived from carboxylic acid compounds (e.g., acetic acid, (meth)acrylic acid, succinic acid, maleic acid, and itaconic acid) (i.e., the residue of a carboxylic acid compound attached to nanocellulose as a result of the reaction between the hydroxyl groups of nanocellulose and the carboxyl groups of the carboxylic acid compound).

[0058] Modifying groups introduced onto the carboxy groups of nanocellulose include, for example, groups derived from amino compounds (e.g., polyetheramines) (i.e., the remainder or all of the amine compound attached to the nanocellulose as a result of the reaction between the carboxy groups of the nanocellulose and the amino groups of the amine compound).

[0059] Nanocellulose is a collection of individual fibers. When nanocellulose contains carboxylated nanocellulose, it is sufficient that it contains at least one carboxylated nanocellulose, and it is preferable that carboxylated nanocellulose is the main component. Here, carboxylated nanocellulose being the main component means that the proportion of carboxylated nanocellulose in the total amount of nanocellulose exceeds 50% by mass, preferably exceeds 70% by mass, and more preferably exceeds 80% by mass. The upper limit of the above proportion is 100% by mass, but it may also be 98% by mass or 95% by mass.

[0060] (N-oxyl compounds) It is preferable that nanocellulose is substantially free of N-oxyl compounds. The meaning of "substantially free of N-oxyl compounds" and the method for measuring the content of N-oxyl compounds are as described in the above [Oxidized Cellulose] (N-oxyl Compounds) section.

[0061] (carboxyl group amount) The amount of carboxyl groups in nanocellulose, the method for measuring them, and the position at which the carboxyl groups are introduced shall follow the description in the (Carboxy group amount) section of [Oxidized cellulose] above.

[0062] (average fiber length) The average fiber length of nanocellulose is preferably 50 to 3000 nm, more preferably 50 to 700 nm, even more preferably 50 to 500 nm, still more preferably 60 to 300 nm, and particularly preferably 70 to 200 nm.

[0063] (average fiber width) The average fiber width of nanocellulose is preferably 1 to 20 nm, more preferably 1 to 15 nm, even more preferably 1 to 10 nm, and particularly preferably 1 to 5 nm.

[0064] The average fiber length and average fiber width of nanocellulose can be measured by the method described in WO 2022 / 009980.

[0065] (aspect ratio) The aspect ratio of nanocellulose (average fiber length / average fiber width) is preferably 20-1000, more preferably 20-200, even more preferably 30-190, and particularly preferably 40-180.

[0066] (zeta potential) The zeta potential of nanocellulose is preferably -30 mV or less, more preferably -90 mV or more and -30 mV or less, even more preferably -80 mV or more and -30 mV or less, even more preferably -70 mV or more and -30 mV or less, and particularly preferably -65 mV or more and -35 mV or less.

[0067] The zeta potential can be measured by the method described in WO 2022 / 009980.

[0068] (crystallinity) The crystallinity of the nanocellulose is preferably 10 to 70%, more preferably 20 to 70%, even more preferably 30 to 65%, particularly preferably 40 to 60%, and most preferably 50 to 55%.

[0069] The crystallinity can be measured by the method described in WO 2022 / 138759.

[0070] [Method of manufacturing nanocellulose] Nanocellulose can be produced by defibrating the above-mentioned oxidized cellulose. Specific production methods include those described in International Publication Nos. 2022 / 009979 and 2022 / 009980. Nanocellulose can also be obtained by defibrating commercially available oxidized cellulose (e.g., Aronfibro (registered trademark) manufactured by Toagosei Co., Ltd.).

[0071] [Acid anhydride modified polyolefin resin] The resin composition according to this embodiment contains an acid anhydride-modified polyolefin resin.

[0072] The term "acid anhydride-modified polyolefin resin" as used herein refers to a polyolefin resin having an acid anhydride group that has been modified with an acid anhydride compound. The acid anhydride-modified polyolefin resin can be obtained, for example, by reacting an acid anhydride compound with a polyolefin resin to bond them together.

[0073] (acid anhydride compound) The acid anhydride compound preferably has an acid anhydride group and a group capable of bonding to a polyolefin resin. The group capable of bonding to a polyolefin resin is preferably an unsaturated bond, more preferably a double bond, and even more preferably an ethylenic double bond.

[0074] Examples of the acid anhydride compound include maleic anhydride, itaconic anhydride, and citraconic anhydride. Although not particularly limited, the acid anhydride compound is preferably maleic anhydride.

[0075] (Polyolefin resin) The polyolefin resin is a resin containing, as a main component, a structural unit derived from an olefin monomer. The polyolefin resin may also contain a structural unit derived from another monomer polymerizable with the olefin monomer.

[0076] Examples of olefin monomers include ethylene, propylene, and butylene. The olefin monomers constituting the polyolefin resin may be one type only, or multiple types.

[0077] Examples of polyolefin resins include polyethylene resins, polypropylene resins, and polybutylene resins. Although not particularly limited, the polyolefin resin is preferably polypropylene resin.

[0078] With respect to the polyethylene resin, the amount of structural units derived from ethylene monomers is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more, based on all structural units constituting the polyethylene resin.

[0079] With respect to the polypropylene resin, the amount of structural units derived from propylene monomers is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more, based on all structural units constituting the polypropylene resin.

[0080] With respect to polybutylene resins, the amount of constituent units derived from butylene monomers is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more, based on all constituent units constituting the polybutylene resin.

[0081] (Weight average molecular weight) The weight average molecular weight of the acid anhydride-modified polyolefin resin is preferably 50,000 to 100,000, more preferably 62,000 to 98,000, and even more preferably 83,000 to 95,100. When the weight average molecular weight is 50,000 to 100,000, peel strength tends to be further improved.

[0082] The weight average molecular weight of the acid anhydride-modified polyolefin resin can be determined by measuring it by gel permeation chromatography (GPC) and converting it into polystyrene equivalent.

[0083] (acid number) The acid value of the acid anhydride-modified polyolefin resin is preferably more than 0 mgKOH / g and not more than 50 mgKOH / g, more preferably from 5 to 45 mgKOH / g, even more preferably from 10 to 40 mgKOH / g, and particularly preferably from 15 to 30 mgKOH / g. When the acid value is more than 0 mgKOH / g and not more than 50 mgKOH / g, the peel strength tends to be further improved.

[0084] The acid value of the acid anhydride-modified polyolefin resin can be determined by the method described in Japanese Patent No. 6,668,136.

[0085] (Melting Point) The melting point of the acid anhydride-modified polyolefin resin is preferably 50 to 120° C., more preferably 65 to 118° C., still more preferably 68 to 96° C., and particularly preferably 71 to 74° C. When the melting point is 50 to 120° C., peel strength tends to be further improved.

[0086] The melting point of the acid anhydride-modified polyolefin resin can be determined by measuring with a differential scanning calorimeter and determining the temperature at which the resin shows a melting peak when the temperature is increased from room temperature.

[0087] The resin composition according to the present embodiment preferably contains an acid anhydride-modified polyolefin resin as a main component. When the resin composition according to the present embodiment contains an acid anhydride-modified polyolefin resin as a main component, the proportion of the acid anhydride-modified polyolefin resin in the resin composition according to the present embodiment may be more than 50% by mass, preferably 55% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and still more preferably 80% by mass or more.

[0088] In the resin composition according to this embodiment, the ratio of the mass (solid content) of the chemically modified nanocellulose to the mass (solid content) of the acid anhydride modified polyolefin resin (mass of chemically modified nanocellulose / mass of acid anhydride modified polyolefin resin) is not particularly limited, but is preferably 0.1 to 20%, more preferably 0.5 to 15%, and even more preferably 0.5 to 10%.

[0089] [Optional ingredients] The resin composition according to this embodiment may contain additives, such as coupling agents, antioxidants, ultraviolet absorbers, flame retardants, fillers, leveling agents, antifoaming agents, thickeners, and dyes.

[0090] <Cured product> One embodiment of the present invention is a cured product obtained by curing the above-described resin composition. Here, the term "cured product of the resin composition" as used herein refers to a product in which the properties of the resin composition, such as viscosity and fluidity, have changed. Curing of the resin composition as used herein also includes, for example, a case in which the resin component is crystallized by removing the solvent from the resin composition.

[0091] <Adhesive> One embodiment of the present invention relates to an adhesive comprising the resin composition described above.

[0092] The adhesive may be in a solid state or in a solution state. In the case of a solid, the adhesive may be in the form of, for example, a pellet, a stick, or a film. Furthermore, if the adhesive is in the form of a solution, it can be applied to any substrate, or if the adhesive is in the form of a solid, it can be placed on any substrate, and used to bond the substrate to another substrate via an adhesive layer. Therefore, one embodiment of the present invention is a laminate with an adhesive layer, comprising an adhesive layer containing an adhesive and a substrate in contact with at least one surface of the adhesive layer.

[0093] The adhesive is preferably a hot melt adhesive, and therefore preferably in a solid state.

[0094] The hot melt adhesive is preferably applied in an application gun (eg, a glue gun). [Example]

[0095] The present invention will be described in more detail below using examples and comparative examples, but the technical scope of the present invention is not limited to these.

[0096] Various values ​​in the examples may be used as preferred lower or upper limits in the embodiments of the present invention. Two values ​​of the same type in the examples may be appropriately combined to form a preferred numerical range.

[0097] <Preparation of nanocellulose> [Manufacturing Example 1] (oxidation process) Pulp (KC Flock W100GK, Nippon Paper Industries Co., Ltd.) was used as the cellulosic raw material. 350 g of sodium hypochlorite pentahydrate crystals with an effective chlorine concentration of 42% by mass were placed in a beaker, and pure water was added and stirred to obtain an aqueous sodium hypochlorite solution with an effective chlorine concentration of 21% by mass. 35% by mass of hydrochloric acid was added thereto and stirred to adjust the pH to 11.0. This aqueous sodium hypochlorite solution was heated to 30°C in a constant temperature water bath while being stirred at 200 rpm using a propeller-type stirring blade in a Shinto Scientific mixer (Three-One Motor, BL600), and then 50 g of the above pulp was added. After adding the cellulosic raw material, the mixture was kept at 30°C in the same thermostatic water bath while adding a 48% by mass aqueous solution of sodium hydroxide to maintain the pH at 11.0 during the reaction. The mixture was stirred at 200 rpm using a propeller-type stirring blade, and the oxidation reaction was carried out for 4 hours (pH maintenance was continued). After the reaction was completed, the filter cloth (manufactured by Nakao Filter Co., Ltd., KE022, air permeability 0.3 cc / cm 2 The product was subjected to solid-liquid separation by pressure filtration using a pressure filter (pressure filtration rate: 1000 kJ / sec), and the resulting oxidized cellulose solid was washed with pure water. The amount of carboxyl groups in the oxidized cellulose was 0.7 mmol / g.

[0098] (Measurement of available chlorine concentration in sodium hypochlorite solution) The available chlorine concentration in the aqueous sodium hypochlorite solution was measured by the following method. Precisely weigh 0.582 g of an aqueous solution prepared by adding sodium hypochlorite pentahydrate crystals to pure water, add 50 mL of pure water, add 2 g of potassium iodide and 10 mL of acetic acid, immediately seal tightly, and leave it in the dark for 15 minutes. After leaving it for 15 minutes, the liberated iodine was titrated with a 0.1 mol / L sodium thiosulfate solution (solution factor 1.000). As a result (indicator starch test solution), the titration volume was 34.55 mL. Separately, a blank test was conducted for correction. Since 1 mL of the 0.1 mol / L sodium thiosulfate solution corresponds to 3.545 mg of Cl, the available chlorine concentration in the aqueous sodium hypochlorite solution was 21% by mass.

[0099] (Fibrillation process) For an aqueous dispersion of Na-type oxidized cellulose (solid content 5.0% by mass), treatment was carried out at 10,000 rpm with a homomixer (manufactured by TOKUSHU KIKA, Robomix) and a liquid volume of 500 g for 40 minutes to fibrillate the oxidized cellulose into nanocellulose, and an aqueous nanocellulose dispersion was obtained. The obtained aqueous nanocellulose dispersion was diluted with pure water to adjust the solid content concentration to 2.0% by mass. An aqueous 1N hydrochloric acid solution was added to the aqueous nanocellulose dispersion and adjusted to a pH of 2.0 - 2.1. Then, using a tabletop multi-shelf centrifuge (manufactured by KOKUSAN, H-40α), it was washed twice with pure water. Thereafter, after washing (substitution) four times with acetone in the same manner, acetone-substituted H-type nanocellulose was obtained by concentration through suction filtration using a vacuum pump.

[0100] <T-peel test T-peel test> [Example 1] Put 20 g of maleic anhydride-modified polypropylene resin (MAPP) (TOYO-TAC (registered trademark) PMA-L, manufactured by Toyobo Co., Ltd., weight average molecular weight: 83,000, acid value: 30 mg KOH / g, melting point: 71°C) on a metal vat lined with a Teflon sheet, heat and melt it in an oven at a temperature of 140°C for 3 hours, then perform vacuum pumping for 15 hours using a pump under the same temperature conditions to sufficiently perform dehydration treatment and the ring-closure reaction of maleic acid. Next, put 19 g of MAPP into a glass bottle, add a toluene solvent so that the concentration becomes 5.8% by mass, and stir it with a magnetic stirrer at room temperature for 15 hours to completely dissolve it. H-type nanocellulose was added to the MAPP toluene solution so that the ratio was 300 parts to MAPP, and toluene was added to adjust the concentration of H-type nanocellulose to 1.3% by mass. Next, the solution was heated to reflux at 100°C and stirred with a magnetic stirrer for 2 hours to graft MAPP and nanocellulose. The resulting reaction solution was diluted with a 5.8% by mass MAPP toluene solution to adjust the solids ratio of MAPP to nanocellulose to 95:5.

[0101] The adjusted concentration solution was poured into a glass petri dish, placed on a hot plate, and heated at 40°C for 15 hours to evaporate the toluene, yielding a film. The resulting film was folded into four and pressed for 90 seconds at 140°C and 9 kPa using a precision hot press (CYPT, manufactured by Shinto Kogyo Co., Ltd.). The film was then recovered and allowed to cool at room temperature. This process was repeated three times to produce a film with uniformly dispersed nanocellulose. The resulting film was cut into a 5 cm x 2 cm piece. It was sandwiched between two 5 cm x 5 cm pieces of aluminum foil (50 μm thick) so that the long edge of the film was aligned with one edge of the aluminum foil. Using a heat press, the film was pressed for 90 seconds at 140°C and 9 kPa with a spacer sandwiched between them to ensure an adhesive layer thickness of approximately 100-150 μm. The film was then allowed to cool at room temperature for at least 15 hours. The film was then cut into a 1 cm x 5 cm piece with an adhesive surface of 1 cm x 2 cm to obtain a test specimen. The resulting test specimen was analyzed using an autograph (Shimadzu Corporation, AGX-V2). The peel test was performed three times at room temperature at 100 mm / min. The average value of the three measurements within the stable load range was 6.37 N / mm. The results are shown in Figure 1.

[0102] [Comparative Example 1] Test pieces were obtained in the same manner as in Example 1, except that nanocellulose was not used, and the peel test was performed three times. The average of the three measurement results in the range where the load was stable was 0.95 N / mm. The results are shown in Figure 2.

[0103] As can be seen from Figures 1 and 2, the adhesive strength was significantly improved by using a combination of MAPP and nanocellulose. Furthermore, during the peel test, interfacial separation occurred between the aluminum foil and the film in Comparative Example 1, whereas cohesive failure of the film occurred in Example 1. From these results, it is estimated that the adhesive strength at the interface between the aluminum foil and the film in Example 1 is improved.

Claims

1. Chemically modified nanocellulose, an acid anhydride-modified polyolefin resin; A resin composition comprising:

2. The chemically modified nanocellulose has a carboxy group. The resin composition according to claim 1.

3. The chemically modified nanocellulose is oxidized nanocellulose; The resin composition according to claim 1.

4. The chemically modified nanocellulose contains an oxide of a cellulosic raw material with hypochlorous acid or a salt thereof, and is substantially free of N-oxyl compounds; The resin composition according to claim 1.

5. The chemically modified nanocellulose has a structure in which the second and third hydroxyl groups of the glucopyranose ring are oxidized and dicarboxyl groups are introduced, The resin composition according to claim 1.

6. The acid anhydride-modified polyolefin resin includes a maleic anhydride-modified polyolefin resin. The resin composition according to claim 1.

7. The acid anhydride-modified polyolefin resin includes a maleic anhydride-modified polypropylene resin. The resin composition according to claim 1.

8. The acid anhydride-modified polyolefin resin has a weight average molecular weight of 50,000 to 100,000. The resin composition according to claim 1.

9. The acid anhydride-modified polyolefin resin has an acid value of more than 0 mgKOH / g and not more than 50 mgKOH / g. The resin composition according to claim 1.

10. The acid anhydride-modified polyolefin resin has a melting point of 50 to 120°C. The resin composition according to claim 1.

11. At least some of the hydroxyl groups of the chemically modified nanocellulose; At least a portion of the carboxy groups of the acid anhydride-modified polyolefin resin; are bonded to form an ester bond, The resin composition according to claim 1.

12. The ratio of the peel strength of the resin composition to the peel strength of a control resin composition obtained by excluding the chemically modified nanocellulose from the resin composition is 1.3 or more; The resin composition according to claim 1.

13. A cured product obtained by curing the resin composition according to any one of claims 1 to 12.

14. An adhesive comprising the resin composition according to any one of claims 1 to 12.

15. an adhesive layer comprising the adhesive of claim 14; a substrate in contact with at least one surface of the adhesive layer; A laminate with an adhesive layer comprising:

16. A hot melt adhesive comprising the resin composition according to any one of claims 1 to 12.

17. It is in pellet, stick, or film form.

17. The hot melt adhesive of claim 16.

18. 17. An applicator gun comprising the hot melt adhesive of claim 16.

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