Polyolefin resin surface modifier

Abstract

To provide a surface modifier for a polyolefin resin that can impart strong adhesiveness to a polyolefin resin molding and that allows easy reduction of the number of polymerization reaction steps.SOLUTION: A surface modifier for a polyolefin resin containing a polymer composed of structural units represented by the following formula (1), wherein n is a number of 2 or more and 1000 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a surface modifier for polyolefin resins, a polyolefin resin composition, and a polyolefin resin molded article. [Background technology]

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

[0003] A method of adding a surface modifier to a polyolefin resin molded article to impart specific physical properties to the article has been investigated.

[0004] For example, Patent Document 1 discloses a method for producing a molded article in which a kneaded resin obtained by kneading a thermoplastic resin and a side-chain crystalline block copolymer is melt-molded to modify the surface layer of the molded article. In Patent Document 1, the side-chain crystalline block copolymer functions as a surface modifier for thermoplastic resins. Specifically, it is disclosed that the block copolymer is a block copolymer of a polymer having a crystalline structure in the side chain and a polymer having a surface modifying structure. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-195403 Summary of the Invention [Problem to be solved by the invention]

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

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

[0008] As a result of extensive research, the present inventors have found that strong adhesion can be imparted to polyolefin resin molded articles by using a surface modifier for polyolefin resins containing a polymer consisting of structural units represented by the following formula (1). 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, and have completed the present invention.

[0009] That is, the present invention is a surface modifier for polyolefin resins, which comprises a polymer consisting of a structural unit represented by the following formula (1).

[0010] [ka] (In formula (1), R 1 and R 2 each independently represents a hydrogen atom or 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).

[0011] In the surface modifier for polyolefin resins of the present invention, in the above formula (1), R 1 and R 2 is preferably an ethyl group. In addition, in the above formula (1), X is preferably a linear or branched alkylene group having 1 to 3 carbon atoms. In addition, in the above formula (1), R 3 is preferably a methyl group. In addition, in the above formula (1), n ​​is preferably 5 or more and 500 or less. The present invention also provides a polyolefin resin composition containing the above-mentioned surface modifier for polyolefin resins and a polyolefin resin. In the polyolefin resin composition of the present invention, the content of the surface modifier is preferably 0.05 parts by mass or more and 10 parts by mass or less, and more preferably 1 part by mass or more and 3 parts by mass or less, per 100 parts by mass of the polyolefin resin. The polyolefin resin is preferably a polypropylene resin. The present invention also provides a polyolefin resin molded article made from the polyolefin resin composition. [Effects of the Invention]

[0012] The present invention provides a surface modifier for polyolefin resins that can impart strong adhesiveness to polyolefin resin molded articles and can be easily produced (reducing the number of polymerization reaction steps). [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is an explanatory diagram showing the test method for the tensile breaking strength test. DETAILED DESCRIPTION OF THE INVENTION

[0014] <Surface modifier for polyolefin resin> The surface modifier for polyolefin resin of the present invention is a surface modifier for polyolefin resin that contains a polymer composed of a structural unit represented by the following formula (1).

[0015] [ka] (In formula (1), R 1 and R 2 each independently represents a hydrogen atom or a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms; R 3represents 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 including a polymer composed of the structural unit represented by formula (1), strong adhesiveness can be imparted to polyolefin resin molded articles. Furthermore, since the polymer composed of the constitutional unit represented by formula (1) is a homopolymer, it can be produced more easily (reducing the number of polymerization reaction steps) than conventional surface modifiers containing block polymers.

[0017] (Polymer consisting of structural units represented by formula (1)) In formula (1), R 1 and R 2 each independently represents a hydrogen atom or a linear, branched, or cyclic alkyl group having from 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 that functionality can be imparted with a small amount when kneading the polyolefin resin, the alkyl group is preferably a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, more preferably a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and even more preferably an ethyl group.

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

[0020] X represents a divalent linking group. The divalent linking group may be a linear or branched alkylene group, an alkenylene group, an arylene group, or a combination of these groups. The alkylene group and alkenylene group may have an alicyclic structure such as a cycloalkylene group or a cycloalkenylene group.

[0021] From the viewpoint that a small amount of X can impart functionality 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 formula (1), n ​​is 2 or more and 1,000 or less. From the viewpoint of ease of melt-kneading into polyolefin resins, n is preferably 3 or more and 750 or less, and more preferably 5 or more and 500 or less.

[0023] The weight average molecular weight of the polymer consisting of the structural unit 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-kneading into polyolefin resins. The weight-average molecular weight is calculated by converting the retention time (retention volume) measured using a gel permeation chromatograph (GPC) into the molecular weight of polystyrene using the retention time (retention volume) of a standard polystyrene of known molecular weight measured under the same conditions. In addition, when the polymer is difficult to dissolve in a solvent and it is difficult to measure the weight average molecular weight, the weight average molecular weight of each polymer may be calculated by a method such as elemental analysis, IR, or NMR.

[0024] (Method for producing a polymer comprising a structural unit represented by formula (1)) A polymer comprising a structural unit represented by formula (1) can be produced by polymerizing a (meth)acrylate containing an amino group. In this specification, (meth)acrylate means acrylate and / or methacrylate.

[0025] Examples of the (meth)acrylate containing an 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. Among these, 2-(diethylamino)ethyl (meth)acrylate is preferred, and 2-(diethylamino)ethyl methacrylate is more preferred, from the viewpoint that functionality can be imparted with a small amount when kneaded with a polyolefin resin.

[0026] The amino group-containing (meth)acrylate may be a commercially available product (reagent), or if necessary, a purified commercially available product (reagent) may be used.

[0027] The polymerization method for the polymer comprising the constitutional unit represented by formula (1) is not particularly limited, and polymerization can be performed by known techniques such as various radical polymerizations and living polymerization methods (radical, anionic, cationic), etc. Examples of living radical polymerization methods that can be used include the NMP method, the ATRP method, and the RAFT method.

[0028] For example, the amino group-containing (meth)acrylate, a polymerization initiator, and a solvent are added, and polymerization is carried out in a reactor at an appropriate polymerization temperature under a nitrogen atmosphere or the like while being appropriately stirred.

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

[0030] The amount of the polymerization initiator used is preferably, for example, 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the amino group-containing (meth)acrylate.

[0031] Examples of the solvent include xylene, butyl acetate, and decane.

[0032] The temperature at which the polymerization reaction is carried out is preferably, for example, about 60°C to 120°C. The polymerization reaction is preferably carried out in an inert gas atmosphere (for example, a nitrogen atmosphere). The polymerization time is not particularly limited, and for example, the reaction solution may be sampled every two hours and the reaction may be carried out until an increase in molecular weight can no longer be confirmed by GPC.

[0033] After the polymerization reaction, purification may be carried out as necessary. As a purification method, known methods can be used, such as filtration, centrifugation, solvent extraction, and reprecipitation using a poor solvent.

[0034] (others) The surface modifier for polyolefin resin of the present invention may contain additives as needed.

[0035] The additives include a polymerization inhibitor.

[0036] The content of the additive is preferably, for example, 0.01 part by mass or more and 0.05 part by mass or less relative to 100 parts by mass of the amino group-containing (meth)acrylate.

[0037] <Polyolefin-based resin composition> The polyolefin resin composition of the present invention contains the above-mentioned surface modifier for polyolefin resins and a polyolefin resin.

[0038] The polyolefin resin is not particularly limited as long as it can achieve the effects of the present invention, and any conventionally known polyolefin resin can be used. Examples of such polyolefin resins include polyethylene resins, polypropylene resins, polybutene resins, polymethylpentene resins, polybutadiene resins, etc. More specific examples include high-density polyethylene, medium-density polyethylene, linear polyethylene, ethylene copolymers with an ethylene content of 50% by weight or more, preferably 70% by weight or more, propylene homopolymers, propylene copolymers with propylene content of 50% by weight or more, preferably 70% by weight or more, butene homopolymers, butene copolymers with a butene content of 50% by weight or more, preferably 70% by weight or more, methylpentene homopolymers, methylpentene copolymers with a methylpentene content of 50% by weight or more, preferably 70% by weight or more, polybutadiene, etc. When the resin has stereoregularity, it may be isotactic or syndiotactic.

[0039] The copolymer may be a random copolymer or a block copolymer.

[0040] Specific examples of comonomers that can constitute the copolymer include α-olefins having 2 to 12 carbon atoms, such as ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, undecene, and dodecene; bicyclo-type monomers, such as 1,4-endomethylenecyclohexene; (meth)acrylic acid esters, such as methyl (meth)acrylate and ethyl (meth)acrylate; and vinyl acetate.

[0041] The catalyst used to produce the copolymer may be, of course, a commonly used Ziegler-Natta catalyst, but also a catalyst system formed by combining a catalyst in which a transition metal compound (e.g., a titanium halide such as titanium trichloride or titanium tetrachloride) is supported on a carrier mainly composed of a magnesium halide such as magnesium chloride with an alkyl aluminum compound (e.g., triethyl aluminum or diethyl aluminum chloride), or a metallocene catalyst.

[0042] The polyolefin resin is preferably a polypropylene resin from the viewpoint of versatility.

[0043] In the polyolefin resin composition of the present invention, the content of the surface modifier is preferably 0.05 parts by mass or more, more preferably 0.3 parts by mass or more, even more preferably 0.5 parts by mass or more, and particularly preferably 1 part by mass or more, per 100 parts by mass of the polyolefin resin, from the viewpoint of imparting adhesiveness. In addition, the content of the surface modifier is preferably 10 parts by mass or less, and from the viewpoint of suppressing bleeding of the surface modifier, it is more preferably 8 parts by mass or less, even more preferably 5 parts by mass or less, and particularly preferably 3 parts by mass or less.

[0044] The polyolefin resin composition of the present invention may contain additives.

[0045] Examples of the additives include flame retardants, flame retardant assistants, anti-dripping agents, reinforcing materials, fillers, antioxidants, pigments, dyes, conductivity imparting agents, hydrolysis inhibitors, thickeners, plasticizers, lubricants, ultraviolet absorbers, antistatic agents, flow improvers, mold release agents, compatibilizers, heat stabilizers, and crystal nucleating agents.

[0046] The content of the additive may be determined appropriately depending on the type of additive, but for example, it is preferably 0.1 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the surface modifier for polyolefin resin.

[0047] (Manufacturing method) The method for producing the polyolefin resin composition of the present invention is not limited to the above, and may be, for example, a polyolefin resin, a surface modifier, and additives are added, and the mixture is dry-blended in a Henschel mixer. The mixture is then melt-kneaded and extruded in an extruder at a resin temperature of about 180 to 240°C. The resulting strands are then water-cooled (about 25°C) and cut into pellets using a pelletizer or the like.

[0048] <Polyolefin resin molded body> The polyolefin resin molded article of the present invention is made from the above polyolefin resin composition.

[0049] The polyolefin resin molded article of the present invention can be obtained by molding the polyolefin resin composition of the present invention according to a commonly used molding method. The molding method is not particularly limited as long as it produces the effects of the present invention, and any of the conventionally known molding methods such as injection molding, press molding, extrusion molding, blow molding, pressure molding, vacuum molding, rotational molding, and film molding can be used.

[0050] The polyolefin resin molded article of the present invention has strong adhesiveness. In this specification, the adhesiveness of the polyolefin resin molded article is evaluated by carrying out a tensile strength test according to the following method.

[0051] FIG. 1 is an explanatory diagram showing the test method for the tensile breaking strength test. As shown in Figure 1, a polyolefin-based resin molded body was cut to prepare polyolefin-based resin molded body 1 (25 mm wide, 70 mm long, 0.5 mm thick) and polyolefin-based resin molded body 1' (25 mm wide, 70 mm long, 0.5 mm thick). Next, polyolefin-based resin molded body 1 and polyolefin-based resin molded body 1' were stacked, and a cyanoacrylate adhesive (product name: Aron Alpha GEL-10, manufactured by Toagosei Co., Ltd.) was applied to one side to a 12 mm adhesive length (adhesive area 2, 25 mm wide, 12 mm long). The adhesive surface was pressed with finger pressure for 10 seconds, and then the adhesive surface was rolled four times perpendicular to the tensile direction with a roller. The specimen was then fixed using clips and stored for 24 hours at 23°C and 50% RH. This specimen was used as test piece 10. Using a universal testing machine (Instron, product name: 68TM-5), the test piece 10 is gripped at positions 35 mm from both ends with grippers and pulled in the direction of separation (the direction of the arrow shown in Figure 1) at a rate of 10 mm / min, to measure the adhesive strength. The above test is carried out three times, and the average value of the maximum load over the entire measurement range is calculated. The names of the failure modes are based on the Japanese Industrial Standard JIS K 6866:1999.

[0052] In the tensile strength test, CSF (the bonded portion of the polyolefin resin molded article breaks) is preferred, and SF (the polyolefin resin molded article breaks, including yielding) is more preferred. The load at which the test piece breaks is preferably 100N or more, more preferably 300N or more, and even more preferably 500N or more. In the above cases, it is judged that strong adhesiveness was imparted to the polyolefin resin molded article.

[0053] The present specification discloses the following: The present disclosure (1) is a surface modifier for polyolefin resins, which comprises a polymer consisting of a structural unit represented by the following formula (1).

[0054] [ka] (In formula (1), R 1 and R 2 each independently represents a hydrogen atom or 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).

[0055] The present disclosure (2) relates to the above formula (1), R 1 and R 2 is an ethyl group, which is the surface modifier for polyolefin resins described in the present disclosure (1). The present disclosure (3) is a surface modifier for polyolefin resins according to the present disclosure (1) or (2), wherein in the above formula (1), X is a linear or branched alkylene group having 1 to 3 carbon atoms. The present disclosure (4) relates to the above formula (1), R 3 is a methyl group in the surface modifier for polyolefin resins according to any one of the present disclosures (1) to (3). The present disclosure (5) is a surface modifier for polyolefin resins according to any one of the present disclosures (1) to (4), wherein n is 5 or more and 500 or less in the above formula (1). The present disclosure (6) is a polyolefin resin composition containing the surface modifier for polyolefin resin according to any one of the present disclosures (1) to (5) and a polyolefin resin. The present disclosure (7) is the polyolefin resin composition according to the present disclosure (6), in which the content of the surface modifier is 0.05 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the polyolefin resin. The present disclosure (8) is the polyolefin resin composition according to the present disclosure (7), in which the content of the surface modifier is 1 part by mass or more and 3 parts by mass or less per 100 parts by mass of the polyolefin resin. The present disclosure (9) is the polyolefin resin composition according to any one of the present disclosures (6) to (8), wherein the polyolefin resin is a polypropylene resin. The present disclosure (10) is a polyolefin resin molded article made of the polyolefin resin composition according to any one of the present disclosures (6) to (9). [Example]

[0056] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Reagents were used for compounds not specifically mentioned.

[0057] <Preparation of surface modifier for polyolefin resin> [Surface modifier 1] (Pretreatment) A mixture of 2-(diethylamino)ethyl methacrylate and 4-methoxyphenol (80 g, 0.43 mmol) and 1.6 mL of a 20% aqueous sodium hydroxide solution were added to a 300 mL four-neck flask and mixed for 10 minutes. After that, 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 became 10 or less. The mixture was heated to 40°C using a mantle heater and dehydrated under reduced pressure until the water content was 0.05% or less, yielding 2-(diethylamino)ethyl methacrylate.

[0058] (Polymerization reaction) To a 300 mL four-neck flask were added 2-(diethylamino)ethyl methacrylate (60 g, 0.32 mmol), xylene (60 g, 0.57 mmol), and Block Builder (registered trademark) MA (4.56 g, 0.013 mmol, manufactured by Arkema). Next, the pressure was reduced and replaced with nitrogen, and the mixture was heated and stirred to 110° C. Sampling of the reaction solution was carried out every 2 hours, and the polymerization reaction was continued until an increase in molecular weight could no longer be confirmed by GPC (Shimadzu Corporation, Prominence SHIMAZU). After the polymerization reaction was completed, the mixture was cooled to room temperature, 0.24 mL of water was added, and the mixture was stirred for 1 hour. Thereafter, the mixture was filtered under reduced pressure using 5C filter paper (manufactured by Advantec Toyo Co., Ltd.) to obtain a xylene solution.

[0059] (Post-processing) 10 g of the xylene solution was placed in the container of a centrifuge (Hitachi, Ltd., HITACHI CENTRIFUGE 05P-21), and acetonitrile (20 g, 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. Then, acetonitrile (20 g, 0.49 mmol) was added and stirred with a spatula, and then the mixture was centrifuged at 1500 rpm for 10 minutes, and the supernatant was discarded. This procedure was repeated twice. Finally, the resulting solution was vacuum dried in an oven at 90°C for 4 hours to obtain surface modifier 1. When confirmed by GPC (Shimadzu Corporation, Prominence SHIMAZU), surface modifier 1 had the structure shown in formula (2) below. The conditions for GPC analysis during the polymerization reaction and for GPC measurement after the reaction were 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

[0060] [ka] (In formula (2), n is 52, and the weight-average molecular weight is approximately 10,000.)

[0061] [Surface modifier 2] (Preprocessing 1) A mixture of 2-(diethylamino)ethyl methacrylate and 4-methoxyphenol (80 g, 0.43 mmol) and 1.6 mL of a 20% aqueous sodium hydroxide solution were added to a 300 mL four-neck flask and mixed for 10 minutes. After that, 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 became 10 or less. The mixture was heated to 40°C using a mantle heater and dehydrated under reduced pressure until the water content was 0.05% by mass or less, yielding 2-(diethylamino)ethyl methacrylate.

[0062] (Preprocessing 2) A mixture of stearyl acrylate and 4-methoxyphenol was dissolved in a water bath at 50-60°C. A 300 mL four-neck flask was charged with a mixture of stearyl acrylate and 4-methoxyphenol (80 g, 0.25 mmol) and 1.6 mL of a 20% aqueous sodium hydroxide solution, and the mixture was heated to 40° C. and mixed for 10 minutes. After that, the aqueous solution was removed using a dropper, and then 80 mL of water was added and mixed for 5 minutes. This procedure was repeated until the pH of the removed aqueous solution became 9 or less. The mixture was dehydrated under reduced pressure using a mantle heater until the water content reached 0.05% by mass or less, yielding stearyl acrylate.

[0063] (Polymerization Reaction 1) To a 300 mL four-neck flask were added stearyl acrylate (60 g, 0.18 mmol), xylene (60 g, 0.57 mmol), and Block Builder (registered trademark) MA (4.56 g, 0.013 mmol, manufactured by Arkema). Then, the pressure was reduced and replaced with nitrogen, and the mixture was heated and stirred to 110° C. Sampling of the reaction solution was carried out every 2 hours, and the polymerization reaction was continued until an increase in molecular weight could no longer be confirmed by GPC. After the polymerization reaction was completed, the mixture was cooled to room temperature to obtain a xylene solution.

[0064] (Polymerization reaction 2) To the 300 mL four-neck flask used in the polymerization reaction 1, 2-(diethylamino)ethyl methacrylate (60 g, 0.32 mmol) and xylene (60 g, 0.57 mmol) were added. Next, the pressure was reduced and replaced with nitrogen, and the mixture was heated and stirred to 110° C. Sampling of the reaction solution was carried out every 2 hours, and the polymerization reaction was continued until an increase in molecular weight could no longer be confirmed by GPC (Shimadzu Corporation, Prominence SHIMAZU). After the polymerization reaction was completed, the mixture was cooled to room temperature, 0.24 mL of water was added, and the mixture was stirred for 1 hour. Thereafter, the mixture was filtered under reduced pressure using 5C filter paper (manufactured by Advantec Toyo Co., Ltd.) to obtain a xylene solution.

[0065] (Post-processing) 200 g of the xylene solution was placed in a 300 mL recovery flask, and the solvent was removed using an evaporator (manufactured by Yamato Scientific Co., Ltd., RE202). Thereafter, the mixture was vacuum dried in an oven at 90°C for 4 hours to obtain surface modifier 2. When confirmed by GPC (Shimadzu Corporation, Prominence SHIMAZU), surface modifier 2 had the structure shown in formula (3) below. The conditions for GPC analysis during the polymerization reaction and for GPC measurement after the reaction were 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

[0066] [ka] (In formula (3), p was 21, the weight average molecular weight of the p portion was approximately 7000, q was 31, and the weight average molecular weight of the q portion was approximately 6000.)

[0067] [Surface modifier 3] (Pretreatment) A mixture of stearyl acrylate and 4-methoxyphenol was dissolved in a water bath at 50-60°C. A 300 mL four-neck flask was charged with a mixture of stearyl acrylate and 4-methoxyphenol (80 g, 0.25 mmol) and 1.6 mL of a 20% aqueous sodium hydroxide solution, and the mixture was heated to 40° C. and mixed for 10 minutes. After that, the aqueous solution was removed using a dropper, and then 80 mL of water was added and mixed for 5 minutes. This procedure was repeated until the pH of the removed aqueous solution became 9 or less. The mixture was dehydrated under reduced pressure using a mantle heater until the water content reached 0.05% by mass or less, yielding stearyl acrylate.

[0068] (Polymerization reaction) To a 300 mL four-neck flask were added stearyl acrylate (60 g, 0.18 mmol), xylene (60 g, 0.57 mmol), and Block Builder (registered trademark) MA (4.56 g, 0.013 mmol, manufactured by Arkema). Next, the pressure was reduced and replaced with nitrogen, and the mixture was heated and stirred to 110° C. Sampling of the reaction solution was carried out every 2 hours, and the polymerization reaction was continued until an increase in molecular weight could no longer be confirmed by GPC (Shimadzu Corporation, Prominence SHIMAZU). After the polymerization reaction was completed, the mixture was cooled to room temperature, 0.24 mL of water was added, and the mixture was stirred for 1 hour. Thereafter, the mixture was filtered under reduced pressure using 5C filter paper (manufactured by Advantec Toyo Co., Ltd.) to obtain a xylene solution.

[0069] (Post-processing) 10 g of the xylene solution was placed in the container of a centrifuge (Hitachi, Ltd., HITACHI CENTRIFUGE 05P-21), and methanol (20 g, 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. Methanol (20 g, 0.62 mmol) was added and stirred with a spatula, then the mixture was centrifuged at 1500 rpm for 10 minutes, and the supernatant was discarded. This procedure was repeated twice. Finally, the resulting solution was vacuum dried in an oven at 90°C for 4 hours to obtain surface modifier 3. When confirmed by GPC (Shimadzu Corporation, Prominence SHIMAZU), surface modifier 3 had the structure shown in formula (4) below. The conditions for GPC analysis during the polymerization reaction and for GPC measurement after the reaction were 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

[0070] [ka] (In formula (4), r was 19, and the weight-average molecular weight was approximately 6,500.)

[0071] [Polyolefin resin] The following polyolefin resins were prepared: PP (Prime Polymer Co., Ltd., H-700) LDPE (Petrothene (registered trademark) 180R, manufactured by Tosoh Corporation) HDPE (Nipolon Hard (registered trademark) 1000, manufactured by Tosoh Corporation)

[0072] Example 1 <Preparation of Polyolefin Resin Composition> A THF solution containing surface modifier 1 dissolved therein was added to 100 parts by mass of PP in the amount shown in Table 1, and after drying, the mixture was dry-blended in a Henschel mixer to obtain a mixture. The above mixture was melt-kneaded at a resin temperature of 180°C in a twin-screw extruder (nozzle die inner diameter: φ3mm, manufactured by Technovel Co., Ltd.), extruded into water (25°C) in the form of strands, cooled, and cut with a pelletizer to produce a polypropylene resin composition.

[0073] <Preparation of Polyolefin-Based Resin Molded Article> The obtained polypropylene resin composition was molded in an injection molding machine (clamping pressure 40 tons, manufactured by Nissei Plastic Industrial Co., Ltd.) under conditions of a barrel temperature of 180 to 200°C, a mold temperature of 40°C, an injection time of 10 seconds, and a cooling time of 10 seconds, to obtain a corrugated plate (polyolefin resin molded product) consisting of a plate 40 mm wide, 35 mm long, and 1 mm thick connected to another plate 40 mm wide, 35 mm long, and 0.5 mm thick.

[0074] (Examples 2 to 15, Comparative Examples 1 to 6) Polyolefin resin molded articles were obtained in the same manner as in Example 1, except that the type of polyolefin resin and the type and amount of surface modifier added were changed as shown in Tables 1 and 2.

[0075] Example 16 <Preparation of Polyolefin Resin Composition> A THF solution containing surface modifier 1 dissolved therein was added to 100 parts by mass of PP in the amount shown in Table 1, and after drying, the mixture was dry-blended in a Henschel mixer to obtain a mixture. The above mixture was melt-kneaded at a resin temperature of 180°C in a twin-screw extruder (nozzle die inner diameter: φ3mm, manufactured by Technovel Co., Ltd.), extruded into water (25°C) in the form of strands, cooled, and cut with a pelletizer to produce a polypropylene resin composition.

[0076] <Preparation of Polyolefin-Based Resin Molded Article> The obtained polypropylene resin composition was pressed at 200°C and 10 MPa for 2 minutes in a compression molding machine (manufactured by Imoto Machinery Co., Ltd.), and then cooled to 25°C to obtain a plate (polyolefin resin molded product, width 40 mm, length 70 mm, thickness 0.5 mm).

[0077] (Examples 17 to 30, Comparative Examples 7 to 12) Polyolefin resin molded articles were obtained in the same manner as in Example 16, except that the type of polyolefin resin and the type and amount of surface modifier added were changed as shown in Tables 3 and 4.

[0078] <Tensile breaking strength test> FIG. 1 is an explanatory diagram showing the test method for the tensile breaking strength test. As shown in Figure 1, a polyolefin-based resin molded body was cut to prepare polyolefin-based resin molded body 1 (width 25 mm, length 70 mm, thickness 0.5 mm) and polyolefin-based resin molded body 1' (width 25 mm, length 70 mm, thickness 0.5 mm). Next, polyolefin-based resin molded body 1 and polyolefin-based resin molded body 1' were stacked, and a cyanoacrylate adhesive (product name: Aron Alpha GEL-10, manufactured by Toagosei Co., Ltd.) was applied to one side so that the adhesive length was 12 mm (adhesive area 2, width 25 mm, length 12 mm). The adhesive surface was pressed with finger pressure for 10 seconds, and then the adhesive surface was pressed with a roller four times in the direction perpendicular to the tensile direction. The specimen was then fixed using a clip and stored for 24 hours at 23 °C and 50% RH to prepare test piece 10. Using a universal testing machine (Instron, product name: 68TM-5), the test piece 10 was gripped at positions 35 mm from both ends with gripping tools and pulled in the direction of separation (the direction of the arrow shown in Figure 1) at a rate of 10 mm / min, to measure the adhesive strength. The above test was carried out three times, and the average value of the maximum load over the entire measurement range was calculated. The names of the fracture modes were based on the Japanese Industrial Standard JIS K 6866:1999. The evaluation criteria are as follows: (Type of destruction) ◎: SF (Polyolefin resin molded body breaks, including yielding) 〇:CSF (bonding area of ​​polyolefin resin molded body is destroyed) ×: CF (peeling without peeling occurred before the polyolefin resin molded body was destroyed) or AF (peeling occurred before the polyolefin resin molded body was destroyed) (Load at the time of destruction) ◎: SF (Polyolefin resin molded body is destroyed) 〇: 100N or more ×: Less than 100N

[0079] <Bleeding ability> The produced polyolefin resin molded body was observed by imaging IR (manufactured by Thermo Fisher Scientific, product name: Nicolet iN 10) and evaluated according to the following criteria. (Evaluation criteria) 〇: No breeding was confirmed (no breeding) ×: Bleeding was confirmed (Bleeding present)

[0080] <Number of polymerization reaction steps> The number of steps in the polymerization reaction was evaluated according to the following criteria. (Evaluation criteria) ○: Number of steps is 0 or more but less than 2 ×: Number of processes is 2 or more

[0081] [Table 1]

[0082] [Table 2]

[0083] [Table 3]

[0084] [Table 4]

[0085] From the above examples, it was confirmed that the surface modifier for polyolefin resins of the present invention can impart strong adhesion to polyolefin resin molded bodies and can be easily produced (reducing the number of polymerization reaction steps). [Industrial Applicability]

[0086] The present invention provides a surface modifier for polyolefin resins that can impart strong adhesiveness to polyolefin resin molded articles and can be easily produced (reducing the number of polymerization reaction steps). The present invention also provides a polyolefin resin composition using the surface modifier for polyolefin resin, and a polyolefin resin molded article. [Explanation of symbols]

[0087] 1, 1' Polyolefin resin molded body 2 Adhesion area 10 test specimens

Claims

1. A surface modifier for polyolefin resins, comprising a polymer having a structural unit represented by the following formula (1): 【Chemistry 1】 (In formula (1), R １ and R ２ each independently represents a hydrogen atom or 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.

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

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

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

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

6. A polyolefin resin composition comprising the surface modifier for polyolefin resins according to claim 1 or 2 and a polyolefin resin.

7. 7. The polyolefin resin composition according to claim 6, wherein the content of the surface modifier is 0.05 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the polyolefin resin.

8. 8. The polyolefin resin composition according to claim 7, wherein the content of the surface modifier is 1 part by mass or more and 3 parts by mass or less per 100 parts by mass of the polyolefin resin.

9. The polyolefin resin composition according to claim 6, wherein the polyolefin resin is a polypropylene resin.

10. A polyolefin resin molded article comprising the polyolefin resin composition according to claim 6.

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