Surface modifier for polyolefin resins

Abstract

The present invention provides a surface modifier that imparts adhesion to polyolefin resin molded articles. [Solution] A surface modifier for polyolefin resins comprising a polymer consisting of constituent units represented by the following formula (1) and a solvent, wherein the concentration of the polymer consisting of constituent units represented by formula (1) is 0.01% by mass or more and 20% by mass or less. TIFF2026066779000010.tif67156

Description

[Technical Field]

[0001] The present invention relates to a surface modifier for polyolefin resins and a method for surface modifying polyolefin resin molded articles. [Background technology]

[0002] Polyolefin resin molded articles are required to have physical properties such as adhesiveness on their surface.

[0003] Methods are being investigated for imparting specific physical properties to polyolefin resin molded bodies by contacting them with surface modifiers.

[0004] For example, Patent Document 1 discloses a method for modifying a polypropylene resin molded article, which includes a step of bringing a copolymer solution containing a side-chain crystalline block copolymer into contact with a polypropylene resin molded article at a temperature of 40 to 120°C. Patent Document 1 discloses that the above-mentioned side-chain crystalline block copolymer functions as a surface modifier for thermoplastic resins. Specifically, it discloses a block copolymer of a polymer having a crystalline structure in its side chains and a polymer having a modifying effect structure. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-137779 [Overview of the project] [Problems that the invention aims to solve]

[0006] The copolymer solution described in Patent Document 1 can impart adhesion to molded articles of thermoplastic resins (polyolefin resins), but because it is a block copolymer, it has the problem of requiring multiple steps in the polymerization reaction.

[0007] Therefore, the present invention aims to provide a surface modifier for polyolefin resins that can impart adhesion to polyolefin resin molded articles and can be easily manufactured (by reducing the number of polymerization reaction steps). [Means for solving the problem]

[0008] As a result of diligent research, the inventors have found that by using a surface modifier for polyolefin resins that contains a polymer consisting of structural units represented by formula (1) described later, and a solvent, and that contains a specific amount of the polymer, adhesion can be imparted to molded polyolefin resin articles. Furthermore, they have found that because the surface modifier for polyolefin resins is a polymer consisting of specific structural units, the number of polymerization reaction steps can be reduced compared to surface modifiers that are block copolymers, thus completing the present invention.

[0009] In other words, the present invention is a surface modifier for polyolefin resins comprising a polymer consisting of constituent units represented by the following formula (1) and a solvent, wherein the concentration of the polymer consisting of constituent units represented by the above formula (1) is 0.01% by mass or more and 20% by mass or less.

[0010] [ka] (In formula (1), R 1 and R 2 Each of these independently represents a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, and R 3 (where represents a hydrogen atom or a methyl group, X represents a divalent linking group, and n is between 2 and 1000).

[0011] In the surface modifier for polyolefin resins of the present invention, in formula (1) above, R 1 and R 2 It is preferable that it be an ethyl group. Furthermore, in formula (1) above, X is preferably a linear or branched alkylene group having 1 to 3 carbon atoms. Also, in equation (1) above, R3 is preferably a methyl group. In the above formula (1), n is preferably 5 or more and 500 or less. In addition, the concentration of the polymer composed of the structural unit represented by the above formula (1) is preferably 0.3% by mass or more and 5% by mass or less. The solvent is preferably at least one solvent selected from the group consisting of aromatic hydrocarbon solvents, halogenated aromatic hydrocarbon solvents, alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, aliphatic hydrocarbon solvents, halogenated aliphatic hydrocarbon solvents, dimethyl sulfoxide, and ionic liquids. The present invention is also a method for surface modification of a polyolefin resin molded body, which includes a step of bringing the surface modifier for the polyolefin resin into contact with the polyolefin resin molded body. In the above step, the temperature of the surface modifier for the polyolefin resin is preferably 40°C or more and 120°C or less. The time for bringing the surface modifier for the polyolefin resin into contact with the polyolefin resin molded body is preferably 1 second or more and 60 minutes or less.

Advantages of the Invention

[0012] The present invention provides a surface modifier for a polyolefin resin that can impart adhesiveness to a polyolefin resin molded body and can be easily produced (by reducing the number of steps in the polymerization reaction).

Brief Description of the Drawings

[0013] [Figure 1] FIG. 1 is an explanatory diagram showing a test method for a tensile fracture strength test.

Embodiments for Carrying Out the Invention

[0014] <Surface Modifier for Polyolefin Resin> The surface modifier for polyolefin resins of the present invention contains a polymer composed of a structural unit represented by the following formula (1) and a solvent, and the concentration of the polymer composed of the structural unit represented by the formula (1) is 0.01% by mass or more and 20% by mass or less.

[0015] [Chemical formula] (In formula (1), R 1 and R 2 each independently represent a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, R 3 represents a hydrogen atom or a methyl group, X represents a divalent linking group, and n is 2 or more and 1000 or less).

[0016] By containing a polymer composed of a structural unit represented by the formula (1) and a solvent and the concentration of the polymer composed of the structural unit represented by the formula (1) being within a specific range, adhesiveness can be imparted to a polyolefin resin molded body. In addition, since the polymer composed of the structural unit represented by the formula (1) is a homopolymer, it can be easily produced (the number of steps in the polymerization reaction is reduced) as compared with conventional surface modifiers containing block copolymers.

[0017] (Polymer composed of the structural unit represented by the formula (1)) In formula (1), R 1 and R 2 each independently represent a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms. The cyclic alkyl group may be an alicyclic alkyl group or an alkyl group having an aromatic ring.

[0018] R 1 and R 2 From the viewpoint of imparting functionality in a small amount when kneading a polyolefin resin, a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms is preferable, a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms is more preferable, and an ethyl group is even more preferable.

[0019] In formula (1), R 3 represents a hydrogen atom or a methyl group. From the perspective of ease of acquisition and legal regulations such as PRTR, a methyl group is preferable.

[0020] X represents a divalent linking group. Examples of the divalent linking groups mentioned above include linear or branched alkylene groups, alkenylene groups, arylene groups, or combinations thereof. Furthermore, the alkylene group and alkenylene group may have an alicyclic structure, such as a cycloalkylene group or a cycloalkenylene group.

[0021] From the viewpoint of imparting functionality with a small amount when the resin is kneaded, X is preferably a linear or branched alkylene group having 1 to 6 carbon atoms, and more preferably a linear or branched alkylene group having 1 to 3 carbon atoms.

[0022] In equation (1), n ​​is between 2 and 1000. From the viewpoint of ease of melt-mixing with polyolefin resins, n is preferably 3 to 750, and more preferably 5 to 500.

[0023] The weight-average molecular weight of the polymer consisting of the constituent units represented by formula (1) is preferably 1000 or more, more preferably 1500 or more, and even more preferably 2000 or more, from the viewpoint of ease of melt-mixing into polyolefin resins. The weight-average molecular weight was calculated by converting the retention time (retention volume) measured using gel permeation chromatography (GPC) to the molecular weight of polystyrene using the retention time (retention volume) of standard polystyrene with a known molecular weight, measured under the same conditions. Furthermore, if the above polymer is poorly soluble in the solvent and difficult to measure the weight-average molecular weight, the weight-average molecular weight of each polymer may be calculated using methods such as elemental analysis, IR, or NMR.

[0024] (Method for producing a polymer consisting of constituent units represented by formula (1)) A polymer consisting of the constituent units represented by formula (1) can be produced by polymerizing an amino group-containing (meth)acrylate. In this specification, (meth)acrylate means acrylate and / or methacrylate.

[0025] Examples of (meth)acrylates containing the above amino group include 2-(dimethylamino)ethyl (meth)acrylate, 2-(diethylamino)ethyl (meth)acrylate, 2-(tert-butylamino)ethyl (meth)acrylate, 2-(methylundecylamino)ethyl (meth)acrylate, and 5-(dimethylamino)pentenyl (meth)acrylate. In particular, 2-(diethylamino)ethyl (meth)acrylate is preferred, and 2-(diethylamino)ethyl methacrylate is more preferred, from the viewpoint that it can impart functionality in small amounts when kneading polyolefin resins.

[0026] The (meth)acrylate containing the above amino group may be a commercially available product (reagent), and if necessary, a purified version of the commercially available product (reagent) may be used.

[0027] The polymerization method for polymers consisting of the constituent units represented by formula (1) is not particularly limited and can be performed by known techniques such as various radical polymerization methods and living polymerization methods (radical, anion, cation). As living radical polymerization methods, the NMP method, ATRP method, RAFT method, etc., can be used.

[0028] For example, the above-mentioned amino group-containing (meth)acrylate, polymerization initiator, and solvent can be added, and polymerization can be carried out in a reactor at an appropriate polymerization temperature while stirring as needed, under a nitrogen atmosphere or the like.

[0029] The polymerization initiator can be appropriately selected from known radical polymerization initiators such as azo compounds, persulfates, and peroxides. Specifically, examples include BlocBuilder®MA (manufactured by Arkema) and AIBN.

[0030] The amount of polymerization initiator used is preferably, for example, 1 to 10 parts by mass per 100 parts by mass of (meth)acrylate containing the above amino group.

[0031] Examples of the solvents mentioned above include xylene, butyl acetate, and decane.

[0032] The temperature at which the polymerization reaction is carried out is preferably around 60°C to 120°C. Polymerization reactions are preferably carried out under an inert gas atmosphere (for example, under a nitrogen atmosphere). The polymerization time is not particularly limited; for example, the reaction can be continued until the molecular weight no longer increases, as can be observed by sampling the reaction solution every two hours using GPC.

[0033] After the polymerization reaction described above, purification may be performed as needed. Known methods can be used for purification, such as filtration, centrifugation, solvent extraction, and reprecipitation using a poor solvent.

[0034] (solvent) The solvent used can be one that is capable of dissolving and dispersing polymers consisting of the constituent units represented by formula (1).

[0035] The solvent is preferably one or more solvents selected from the group consisting of aromatic hydrocarbon solvents, halogenated aromatic hydrocarbon solvents, alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, aliphatic hydrocarbon solvents, halogenated aliphatic hydrocarbon solvents, dimethyl sulfoxide, and ionic liquids.

[0036] Examples of the above-mentioned aromatic hydrocarbon solvents include toluene, xylene (o-xylene, m-xylene, p-xylene, and mixtures thereof), mesitylene, ethylbenzene, and cyclohexylbenzene.

[0037] Examples of the above-mentioned halogenated aromatic hydrocarbon solvents include chlorobenzene, dichlorobenzene, trichlorobenzene, bromobenzene, and fluorobenzene.

[0038] Examples of the alcohol-based solvents mentioned above include ethylene glycol, glycerin, 2-methoxyethanol, and 2-ethoxyethanol.

[0039] Examples of the ether-based solvents mentioned above include tetrahydrofuran, 1,4-dioxane, dimethoxyethane, cyclopentyl methyl ether, diglyme, anisole, methylanisole, and dimethoxybenzene.

[0040] Examples of the ketone solvents mentioned above include methyl isobutyl ketone, cyclohexanone, and acetophenone.

[0041] Examples of the above-mentioned amide solvents include N,N-dimethylacetamide, N,N-dimethylformamide, and N-methyl-2-pyrrolidone.

[0042] Examples of the ester solvents mentioned above include ethyl acetate, butyl acetate, and methyl benzoate.

[0043] Examples of the aliphatic hydrocarbon solvents mentioned above include pentane, hexane, octane, decane, cyclohexane, and decalin.

[0044] Examples of the above-mentioned halogenated aliphatic hydrocarbon solvents include trichloromethane, tetrachloromethane, dichloroethane, trichloroethylene, tetrachloroethylene, chlorobutane, and bromoform.

[0045] Examples of the above-mentioned ionic liquids include 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium methylsulfate, and 1-butyl-3-methylimidazolium iodide.

[0046] From the viewpoint of polymer solubility and the Fire Service Act, the above solvent is preferably toluene, xylene, butyl acetate, octane, or decalin, with xylene being more preferred.

[0047] The above solvents may be used individually or as a mixture of two or more.

[0048] (Concentration of the polymer consisting of the constituent units represented by formula (1)) The concentration of the polymer consisting of the constituent units represented by formula (1) is 0.01% by mass or more and 20% by mass or less, relative to the total mass of the surface modifier for polyolefin resins. By having a polymer concentration consisting of the constituent units represented by formula (1) within the above range, adhesion to polyolefin resin molded articles can be imparted.

[0049] The concentration of the polymer consisting of the constituent units represented by formula (1) is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.3% by mass or more, particularly preferably 0.5% by mass or more, and most preferably 1% by mass, based on the total mass of the surface modifier for polyolefin resins. Furthermore, the concentration of the polymer consisting of the constituent units represented by formula (1) is preferably 15% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 3% by mass or less, based on the total mass of the surface modifier for polyolefin resins.

[0050] (others) The surface modifier for polyolefin resins of the present invention may contain additives as needed.

[0051] Examples of the above-mentioned additives include polymerization inhibitors. The amount of the above-mentioned additives should be determined appropriately depending on the type of additive.

[0052] (Method for producing surface modifiers for polyolefin resins) The method for producing the surface modifier for polyolefin resins of the present invention is not particularly limited, and can be obtained by using the materials described above, mixing and stirring them so that the concentration of the polymer consisting of constituent units represented by formula (1) is within a predetermined range. For mixing and stirring, any known method may be used.

[0053] <Method for surface modification of polyolefin resin molded articles> The present invention provides a method for surface modification of a polyolefin resin molded article, comprising the step of bringing a surface modifier for polyolefin resins into contact with the polyolefin resin molded article (also referred to as a contact step).

[0054] (Surface modifier for polyolefin resins) As the surface modifier for the polyolefin resin described above, the surface modifier for polyolefin resin of the present invention described above is used.

[0055] (Polyolefin resin molded product) Polyolefin resin molded articles are obtained by molding a polyolefin resin composition according to a conventional molding method.

[0056] The above polyolefin resin composition includes conventionally known polyolefin resins. Examples of such polyolefin resins include polyethylene resins, polypropylene resins, polybutene resins, polymethylpentene resins, and polybutadiene resins. More specifically, examples include high-density polyethylene, medium-density polyethylene, linear polyethylene, ethylene copolymers with an ethylene content of 50% or more by weight, preferably 70% or more by weight, propylene homopolymers, propylene copolymers with an ethylene content of 50% or more by weight, preferably 70% or more by weight, butene homopolymers, butene copolymers with a butene content of 50% or more by weight, preferably 70% or more by weight, methylpentene homopolymers, methylpentene copolymers with a methylpentene content of 50% or more by weight, preferably 70% or more by weight, and polybutadiene. If the above resin has stereoregularity, it may be isotactic or syndiotactic.

[0057] The copolymer described above may be a random copolymer or a block copolymer.

[0058] Examples of comonomers that can constitute the above copolymer include 2-12 carbon olefins such as ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, undecene, and dodecene; bicyclotype monomers such as 1,4-endomethylenecyclohexene; (meth)acrylic acid esters such as methyl (meth)acrylate and ethyl (meth)acrylate; and vinyl acetate.

[0059] As catalysts applied to produce the above copolymer, in addition to commonly used Ziegler-Natta type catalysts, catalyst systems combining transition metal compounds (e.g., titanium halides such as titanium trichloride and titanium tetrachloride) supported on a carrier mainly composed of magnesium halides such as magnesium chloride, with alkylaluminum compounds (e.g., triethylaluminum, diethylaluminum chloride), metallocene catalysts, and the like can also be used.

[0060] From the viewpoint of versatility, polypropylene resins are preferred among the above polyolefin resins.

[0061] The above polyolefin resin composition may contain additives. Examples of the above-mentioned additives include flame retardants, flame retardant enhancers, anti-dripping agents, reinforcing agents, fillers, antioxidants, pigments, dyes, conductivity enhancers, hydrolysis inhibitors, thickeners, plasticizers, lubricants, UV absorbers, antistatic agents, flow improvers, release agents, compatibilizers, heat stabilizers, and crystal nucleating agents. The amount of the above-mentioned additives should be determined appropriately depending on the type of additive.

[0062] As long as the above polyolefin resin composition is molded in a manner that achieves the effects of the present invention, there are no particular restrictions on the method used, and any conventionally known molding method such as injection molding, press molding, extrusion molding, blow molding, pressure molding, vacuum molding, rotational molding, or film molding can be employed.

[0063] (contact process) In the contact process, the surface modifier for the polyolefin resin is brought into contact with the molded polyolefin resin.

[0064] In the contact process, the temperature of the surface modifier for the polyolefin resin is preferably between 40°C and 120°C. By performing the contact process within the temperature range of the surface modifier for polyolefin resins described above, adhesive properties can be suitably imparted to the molded polyolefin resin. In the contact process, the temperature of the surface modifier for the polyolefin resin is more preferably 50°C to 100°C.

[0065] In the contact process, the contact time between the surface modifier for polyolefin resins and the molded polyolefin resin is preferably 1 second or more and 60 minutes or less. By ensuring the contact time is within the above range, adhesive properties can be suitably imparted to the polyolefin resin molded article. In the contact process, the contact time between the surface modifier for polyolefin resins and the molded polyolefin resin is more preferably 5 seconds or more, even more preferably 10 seconds or more, particularly preferably 20 seconds or more, and most preferably 30 seconds or more. In the contact process, the contact time between the surface modifier for polyolefin resins and the polyolefin resin molded article is more preferably 40 minutes or less, even more preferably 20 minutes or less, and particularly preferably 10 minutes or less. The contact time refers to the period during which the surface modifier for polyolefin resins is in contact with the polyolefin resin molded product at the target temperature.

[0066] In the contact process, the method of bringing the surface modifier for polyolefin resins and the molded polyolefin resin article into contact is not particularly limited. The molded polyolefin resin article may be immersed in the surface modifier for polyolefin resins, the surface modifier for polyolefin resins may be applied to the surface of the molded polyolefin resin article, or the surface modifier for polyolefin resins may be brought into contact with the surface of the molded polyolefin resin article while circulating it. In particular, immersion is preferred from the viewpoint of appropriately controlling the temperature at which the surface modifier for polyolefin resins and the molded polyolefin resin article come into contact. Furthermore, any of the conventionally known molding methods, such as brushes, sprays, or coaters, can be used as the coating method described above.

[0067] (Adhesiveness) The present invention provides a surface modification method for polyolefin resin molded articles that can impart adhesive properties to the polyolefin resin molded articles. In this specification, the adhesion of polyolefin resin molded articles is evaluated by performing a tensile breaking strength test using the following method.

[0068] Figure 1 is an explanatory diagram showing the test method for tensile fracture strength testing. As shown in Figure 1, a polyolefin resin molded body is cut to prepare polyolefin resin molded body 1 (25 mm wide, 70 mm long, 0.5 mm thick) and polyolefin resin molded body 1' (25 mm wide, 70 mm long, 0.5 mm thick). Next, polyolefin resin molded body 1 and polyolefin resin molded body 1' are placed on top of each other, and cyanoacrylate adhesive (product name: Aron Alpha GEL-10, manufactured by Toagosei Co., Ltd.) is applied to one side to create a bonding area of ​​12 mm (bonding area 2, 25 mm wide, 12 mm long). After pressing the bonding surface with a fingertip for 10 seconds, the bonding surface is pressed with a roller four times perpendicular to the tensile direction. After that, it is fixed with a clip and stored for 24 hours at 23°C and 50% RH to obtain test piece 10. Using a universal testing machine (Instron, product name: 68TM-5), the test piece 10 is gripped at a position 35 mm from both ends using a gripping device and pulled in the direction of separation at 10 mm / min (in the direction of the arrow shown in Figure 1) to measure the adhesive strength. The above test is performed three times, and the average value of the maximum load across the entire measurement range is determined.

[0069] If the average value of the above maximum loads is 50N or more, it can be determined that adhesive force has been imparted to the polyolefin resin molded product. The average value of the above maximum load is preferably 100N or more, more preferably 150N or more, even more preferably 200N or more, and particularly preferably 250N or more.

[0070] This specification discloses the following: The present disclosure (1) is a surface modifier for polyolefin resins comprising a polymer consisting of constituent units represented by the following formula (1) and a solvent, wherein the concentration of the polymer consisting of constituent units represented by the above formula (1) is 0.01% by mass or more and 20% by mass or less.

[0071] [ka] (In formula (1), R 1 and R 2Each of these independently represents a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, and R 3 (where represents a hydrogen atom or a methyl group, X represents a divalent linking group, and n is between 2 and 1000).

[0072] Disclosure (2) above, in formula (1), R 1 and R 2 This is a surface modifier for polyolefin resins described in disclosure (1), wherein the ethyl group is present. Disclosure (3) is a surface modifier for polyolefin resins as described in Disclosure (1) or (2), wherein in formula (1), X is a linear or branched alkylene group having 1 to 3 carbon atoms. This disclosure (4) is that in formula (1) above, R 3 The surface modifier for polyolefin resins described in any of (1) to (3) of this disclosure is a methyl group. Disclosure (5) is a surface modifier for polyolefin resins according to any of Disclosures (1) to (4) above, wherein n in formula (1) is 5 or more and 500 or less. Disclosure (6) is a surface modifier for polyolefin resins according to any one of Disclosures (1) to (5), wherein the concentration of the polymer consisting of the constituent units represented by formula (1) above is 0.3% by mass or more and 5% by mass or less. Disclosure (7) is a surface modifier for polyolefin resins according to any one of Disclosures (1) to (6), wherein the solvent is one or more solvents selected from the group consisting of aromatic hydrocarbon solvents, halogenated aromatic hydrocarbon solvents, alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, aliphatic hydrocarbon solvents, halogenated aliphatic hydrocarbon solvents, dimethyl sulfoxide, and ionic liquids. The present disclosure (8) is a method for surface modification of a polyolefin resin molded article, comprising the step of bringing a surface modifier for polyolefin resins into contact with a polyolefin resin molded article. This disclosure (9) is a method for surface modification of a polyolefin resin molded article according to this disclosure (8), wherein the temperature of the surface modifier for the polyolefin resin in the above step is 40°C or more and 120°C or less. Disclosure (10) is a method for surface modification of a polyolefin resin molded article according to Disclosure (8) or (9), wherein the time for which the surface modifier for polyolefin resin and the polyolefin resin molded article are in contact is 1 second or more and 60 minutes or less. [Examples]

[0073] The present invention will be further described in detail below with reference to examples, but the present invention is not limited to these examples. Compounds not specifically mentioned were used as reagents.

[0074] <Preparation of polymers> [Polymer 1] (Pre-processing) A mixture of 2-(diethylamino)ethyl methacrylate and 4-methoxyphenol (80 g, 0.43 mmol) and 1.6 mL of 20% sodium hydroxide aqueous solution were added to a 300 mL four-necked flask and mixed for 10 minutes. Afterward, the aqueous solution was removed using a dropper, and 80 mL of water was added and mixed for 5 minutes. This procedure was repeated until the pH of the removed aqueous solution was 10 or less. The mixture was heated to 40°C using a mantle heater and dehydrated under reduced pressure until the moisture content was 0.05% or less to obtain 2-(diethylamino)ethyl methacrylate.

[0075] (polymerization reaction) 60 g, 0.32 mmol, 2-(diethylamino)ethyl methacrylate, 60 g, 0.57 mmol, and Blockbuilder® MA (4.56 g, 0.013 mmol, Arkema) were added to a 300 mL four-necked flask. Next, the mixture was purged with reduced pressure nitrogen, heated to 110°C, and stirred. The reaction solution was sampled every two hours, and the polymerization reaction was continued until no further increase in molecular weight could be detected using GPC (Prominence SHIMAZU, manufactured by Shimadzu Corporation). After the polymerization reaction was complete, the mixture was cooled to room temperature, and 0.24 mL of water was added and stirred for 1 hour. Then, the xylene solution was obtained by vacuum filtration using 5C filter paper (Advantec Toyo Co., Ltd.).

[0076] (Post-processing) 10 g of xylene solution was placed in the container of a centrifuge (Hitachi Centrifuge 05P-21), 20 g of acetonitrile (0.49 mmol) was added, and the mixture was stirred with a spatula. The mixture was then stirred in the centrifuge at 1500 rpm for 10 minutes, and the supernatant was discarded. Next, acetonitrile (20g, 0.49 mmol) was added and stirred with a spatula. The mixture was then centrifuged at 1500 rpm for 10 minutes, and the supernatant was discarded. This procedure was repeated twice. Finally, the obtained solution was vacuum-dried in a 90°C oven for 4 hours to obtain polymer 1. Confirmation using GPC (Prominence SHIMAZU, manufactured by Shimadzu Corporation) revealed that polymer 1 had the structure shown in formula (2) below. The GPC analysis conditions during the polymerization reaction and the GPC measurement conditions after the reaction are as follows. (Measurement conditions) Column: LF-804 (Shodex) Column temperature: 40℃ Detector: RI Developing solvent: THF (tetrahydrofuran) + triethanolamine (5 mmol / L in THF) Flow rate: 1mL / min

[0077] [ka] (In equation (2), n was 52, and the weight-average molecular weight was approximately 10,000.)

[0078] [polymer2] (Pre-treatment 1) A mixture of 2-(diethylamino)ethyl methacrylate and 4-methoxyphenol (80 g, 0.43 mmol) and 1.6 mL of 20% sodium hydroxide aqueous solution were added to a 300 mL four-necked flask and mixed for 10 minutes. Afterward, the aqueous solution was removed using a dropper, and 80 mL of water was added and mixed for 5 minutes. This procedure was repeated until the pH of the removed aqueous solution was 10 or less. The mixture was heated to 40°C using a mantle heater and dehydrated under reduced pressure until the moisture content was 0.05% by mass or less, to obtain 2-(diethylamino)ethyl methacrylate.

[0079] (Pre-processing 2) A mixture of stearyl acrylate and 4-methoxyphenol was dissolved in a water bath at 50-60°C. A mixture of stearyl acrylate and 4-methoxyphenol (80 g, 0.25 mmol) and 1.6 mL of 20% sodium hydroxide aqueous solution were added to a 300 mL four-necked flask and heated to 40°C, then mixed for 10 minutes. Afterward, the aqueous solution was removed using a dropper, and 80 mL of water was added and mixed for 5 minutes. This procedure was repeated until the pH of the removed aqueous solution was 9 or below. Stearyl acrylate was obtained by performing dehydration under reduced pressure using a mantle heater until the moisture content was 0.05% by mass or less.

[0080] (Polymerization reaction 1) Stearyl acrylate (60 g, 0.18 mmol), xylene (60 g, 0.57 mmol), and Blockbuilder® MA (4.56 g, 0.013 mmol, Arkema) were added to a 300 mL four-necked flask. Next, the mixture was purged with reduced pressure nitrogen and heated to 110°C, followed by stirring. The reaction solution was sampled every two hours, and the polymerization reaction was continued until no further increase in molecular weight could be observed by GPC. After the polymerization reaction was complete, the mixture was cooled to room temperature to obtain a xylene solution.

[0081] (Polymerization reaction 2) 2-(diethylamino)ethyl methacrylate (60 g, 0.32 mmol) and xylene (60 g, 0.57 mmol) were added to the 300 mL four-necked flask used in polymerization reaction 1. Next, the mixture was purged with reduced pressure nitrogen, heated to 110°C, and stirred. The reaction solution was sampled every two hours, and the polymerization reaction was continued until no further increase in molecular weight could be detected using GPC (Prominence SHIMAZU, manufactured by Shimadzu Corporation). After the polymerization reaction was complete, the mixture was cooled to room temperature, and 0.24 mL of water was added and stirred for 1 hour. Then, the xylene solution was obtained by vacuum filtration using 5C filter paper (Advantec Toyo Co., Ltd.).

[0082] (Post-processing) 200 g of xylene solution was placed in a 300 mL round-bottom flask, and the solvent was removed using an evaporator (Yamato Scientific Co., Ltd., RE202). Subsequently, polymer 2 was obtained by vacuum drying in a 90°C oven for 4 hours. Confirmation using GPC (Prominence SHIMAZU, manufactured by Shimadzu Corporation) revealed that polymer 2 had the structure shown in formula (3) below. The GPC analysis conditions during the polymerization reaction and the GPC measurement conditions after the reaction are as follows. (Measurement conditions) Column: LF-804 (Shodex) Column temperature: 40℃ Detector: RI Developing solvent: THF + triethanolamine (5 mmol / L in THF) Flow rate: 1mL / min

[0083] [ka] (In equation (3), p is 21, and the weight-average molecular weight of the p portion is approximately 7000; q is 31, and the weight-average molecular weight of the q portion is approximately 6000.)

[0084] [Polymer 3] (Pre-processing) A mixture of stearyl acrylate and 4-methoxyphenol was dissolved in a water bath at 50-60°C. A mixture of stearyl acrylate and 4-methoxyphenol (80 g, 0.25 mmol) and 1.6 mL of 20% sodium hydroxide aqueous solution were added to a 300 mL four-necked flask and heated to 40°C, then mixed for 10 minutes. Afterward, the aqueous solution was removed using a dropper, and 80 mL of water was added and mixed for 5 minutes. This procedure was repeated until the pH of the removed aqueous solution was 9 or below. Stearyl acrylate was obtained by performing dehydration under reduced pressure using a mantle heater until the moisture content was 0.05% by mass or less.

[0085] (polymerization reaction) Stearyl acrylate (60 g, 0.18 mmol), xylene (60 g, 0.57 mmol), and Blockbuilder® MA (4.56 g, 0.013 mmol, Arkema) were added to a 300 mL four-necked flask. Next, the mixture was purged with reduced pressure nitrogen, heated to 110°C, and stirred. The reaction solution was sampled every two hours, and the polymerization reaction was continued until no further increase in molecular weight could be detected using GPC (Prominence SHIMAZU, manufactured by Shimadzu Corporation). After the polymerization reaction was complete, the mixture was cooled to room temperature, and 0.24 mL of water was added and stirred for 1 hour. Then, the xylene solution was obtained by vacuum filtration using 5C filter paper (Advantec Toyo Co., Ltd.).

[0086] (Post-processing) 10 g of xylene solution was placed in a container of a centrifuge (Hitachi Centrifuge 05P-21), methanol (20 g, 0.62 mmol) was added, and the mixture was stirred with a spatula. The mixture was then stirred in the centrifuge at 1500 rpm for 10 minutes, and the supernatant was discarded. Methanol (20g, 0.62 mmol) was added and stirred with a spatula. The mixture was then centrifuged at 1500 rpm for 10 minutes, and the supernatant was discarded. This procedure was repeated twice. Finally, the obtained solution was vacuum-dried in a 90°C oven for 4 hours to obtain polymer 3. Confirmation using GPC (Prominence SHIMAZU, manufactured by Shimadzu Corporation) revealed that polymer 3 had the structure shown in formula (4) below. The GPC analysis conditions during the polymerization reaction and the GPC measurement conditions after the reaction are as follows. (Measurement conditions) Column: LF-804 (Shodex) Column temperature: 40℃ Detector: RI Developing solvent: THF + triethanolamine (5 mmol / L in THF) Flow rate: 1mL / min

[0087] [ka] (In equation (4), r was 19, and the weight-average molecular weight was approximately 6500.)

[0088] [Fabrication of polyolefin resin molded products] <Fabrication of polyolefin resin molded articles (injection molding)> (Resin molded body 1) Polypropylene pellets (PP, H-700, manufactured by Prime Polymer Co., Ltd.) were molded using an injection molding machine (clamping pressure 40 tons, manufactured by Nissei Plastic Industrial Co., Ltd.) under the conditions of barrel temperature 180-200°C, mold temperature 40°C, injection time 10 seconds, and cooling time 10 seconds to obtain a stepped plate (polyolefin resin molded product) consisting of a plate with a width of 40 mm, a length of 35 mm, and a thickness of 1 mm, and a plate with a width of 40 mm, a length of 35 mm, and a thickness of 0.5 mm, which were connected together.

[0089] (Resin molded body 2) Polyethylene pellets (LDPE, Petrocene® 180R, manufactured by Tosoh Corporation) were molded in an injection molding machine (clamping pressure 40 tons, manufactured by Nissei Plastic Industrial Co., Ltd.) under the conditions of barrel temperature 180-200°C, mold temperature 40°C, injection time 10 seconds, and cooling time 10 seconds to obtain a stepped plate (polyolefin resin molded product) in which a plate with a width of 40 mm, a length of 35 mm, and a thickness of 1 mm was connected to a plate with a width of 40 mm, a length of 35 mm, and a thickness of 0.5 mm.

[0090] (Resin molded body 3) Polyethylene pellets (HDPE, Nipolon Hard® 1000, manufactured by Tosoh Corporation) were molded in an injection molding machine (clamping pressure 40 tons, manufactured by Nissei Plastic Industrial Co., Ltd.) under the conditions of barrel temperature 180-200°C, mold temperature 40°C, injection time 10 seconds, and cooling time 10 seconds to obtain a stepped plate (polyolefin resin molded product) in which a plate with a width of 40 mm, a length of 35 mm, and a thickness of 1 mm was connected to a plate with a width of 40 mm, a length of 35 mm, and a thickness of 0.5 mm.

[0091] <Preparation of polyolefin resin molded products (press molding)> (Resin molded body 4) Polypropylene pellets (H-700, manufactured by Prime Polymer Co., Ltd.) were pressed in a compression molding machine (manufactured by Imoto Seisakusho Co., Ltd.) at 200°C and 10 MPa for 2 minutes, and then cooled to 25°C to obtain a plate (polyolefin resin molded body, 40 mm wide, 70 mm long, 0.5 mm thick).

[0092] (Resin molded body 5) Polyethylene pellets (Nipolon Hard® 1000, manufactured by Tosoh Corporation) were pressed in a compression molding machine (manufactured by Imoto Seisakusho Co., Ltd.) at 200°C and 10 MPa for 2 minutes, and then cooled to 25°C to obtain a plate (polyolefin resin molded body, 40 mm wide, 70 mm long, 0.5 mm thick).

[0093] (Example 1) A surface modifier was prepared by dissolving the synthesized polymer 1 in xylene as a solvent by stirring at room temperature until its concentration reached 0.01% by mass. The resin molded body 1 was immersed in the above surface modifier at 60°C for 30 seconds (contact step). Subsequently, the material was left to stand at room temperature and allowed to air dry, thereby obtaining a surface-modified polyolefin resin molded article.

[0094] (Examples 2-17, Comparative Examples 1-8) A surface-modified polyolefin resin molded article was obtained in the same manner as in Example 1, except that the type of polyolefin resin molded article, the type of polymer, and the concentration of the polymer were changed to those listed in Table 1 or Table 2. In Comparative Examples 1 and 4, polymer-free xylene was used, and polyolefin resin molded articles were obtained in the same manner as in Example 1.

[0095] <Tensile breaking strength test> Figure 1 is an explanatory diagram showing the test method for tensile fracture strength testing. As shown in Figure 1, a polyolefin resin molded body was cut to prepare polyolefin resin molded body 1 (width 25 mm, length 70 mm, thickness 0.5 mm) and polyolefin resin molded body 1' (width 25 mm, length 70 mm, thickness 0.5 mm). Next, polyolefin resin molded body 1 and polyolefin resin molded body 1' were placed on top of each other, and cyanoacrylate adhesive (product name: Aron Alpha GEL-10, manufactured by Toagosei Co., Ltd.) was applied to one side to create a bonding area of ​​12 mm (bonding area 2, width 25 mm, length 12 mm). After pressing the bonding surface with a fingertip for 10 seconds, the bonding surface was pressed with a roller four times perpendicular to the tensile direction. After that, it was fixed with a clip and stored for 24 hours at 23°C and 50% RH to obtain test piece 10. Using a universal testing machine (Instron, product name: 68TM-5), the adhesive strength was measured by gripping the test piece 10 at a distance of 35 mm from both ends with a gripping device and pulling it in the direction of separation at a rate of 10 mm / min (in the direction of the arrow shown in Figure 1). The above test was performed three times, and the average value of the maximum load across the entire measurement range was calculated and evaluated according to the following criteria. (Evaluation Criteria) ◎: Average maximum load is 150N or more ○: Average maximum load is between 50N and 150N. ×: Average maximum load is less than 50N

[0096] <Number of steps in the polymerization reaction> The number of polymerization reaction steps required to obtain a polymer was evaluated according to the following criteria. (Evaluation Criteria) ○: Number of steps is 0 or more but less than 2 ×: Number of steps is 2 or more

[0097] [Table 1]

[0098] [Table 2]

[0099] From the above examples, it was confirmed that the surface modifier for polyolefin resins of the present invention can impart adhesion to polyolefin resin molded articles and can be easily manufactured (by reducing the number of polymerization reaction steps). [Industrial applicability]

[0100] The present invention provides a surface modifier for polyolefin resins that can impart adhesion to polyolefin resin molded articles and can be easily manufactured (by reducing the number of polymerization reaction steps). Furthermore, the present invention provides a method for surface modification of a polyolefin resin molded article using the above-mentioned surface modifier for polyolefin resins. [Explanation of symbols]

[0101] 1, 1' Polyolefin resin molded article 2 Adhesion area 10 test specimens

Claims

1. The material comprises a polymer consisting of constituent units represented by the following formula (1) and a solvent, A surface modifier for polyolefin resins, wherein the concentration of the polymer consisting of the constituent units represented by formula (1) is 0.01% by mass or more and 20% by mass or less. 【Chemistry 1】 (In formula (1), R １ and R ２ Each of these independently represents a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, and R ３ (where represents a hydrogen atom or a methyl group, X represents a divalent linking group, and n is between 2 and 1000.)

2. In formula (1) above, R １ and R ２ The surface modifier for polyolefin resins according to claim 1, wherein is an ethyl group.

3. The surface modifier for polyolefin resins according to claim 1 or 2, wherein in formula (1), X is a linear or branched alkylene group having 1 to 3 carbon atoms.

4. In formula (1) above, R ３ The surface modifier for polyolefin resins according to claim 1 or 2, wherein is a methyl group.

5. The surface modifier for polyolefin resins according to claim 1 or 2, wherein n in formula (1) is 5 or more and 500 or less.

6. The surface modifier for polyolefin resins according to claim 1 or 2, wherein the concentration of the polymer consisting of the constituent units represented by formula (1) is 0.3% by mass or more and 5% by mass or less.

7. The surface modifier for polyolefin resins according to claim 1 or 2, wherein the solvent is one or more solvents selected from the group consisting of aromatic hydrocarbon solvents, halogenated aromatic hydrocarbon solvents, alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, aliphatic hydrocarbon solvents, halogenated aliphatic hydrocarbon solvents, dimethyl sulfoxide, and ionic liquids.

8. A method for surface modification of a polyolefin resin molded article, comprising the step of bringing a surface modifier for polyolefin resins according to claim 1 or 2 into contact with a polyolefin resin molded article.

9. The method for surface modification of a polyolefin resin molded article according to claim 8, wherein the temperature of the surface modifier for the polyolefin resin in the above step is 40°C or more and 120°C or less.

10. The method for surface modification of a polyolefin resin molded article according to claim 8, wherein the time for contacting the surface modifier for polyolefin resins with the polyolefin resin molded article is 1 second or more and 60 minutes or less.

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