Polymers and adhesive compositions

Abstract

To provide a polymer that can be decomposed under mild conditions. [Solution] One aspect of the present invention is a polymer. The polymer contains structural units represented by the following formula (1). When the total amount of the polymer is taken as 100% by mass, the polymer EO content is defined as 10% or more of ethylene oxide units. [Formula 1] TIFF2026083966000014.tif32170{In formula (1), R a This is either a urethane bond, a urea bond, or a thiourethane bond. 11 ~R 13 Each of these is independently either hydrogen or a monovalent organic group.

Description

[Technical Field]

[0001] This invention relates to polymers and adhesive compositions. [Background technology]

[0002] From an environmental protection perspective, there is a great deal of activity in developing biodegradable polymer materials, such as biodegradable resins, photodegradable resins, and pyrodegradable resins, which decompose naturally even after disposal. However, because biodegradable, photodegradable, and pyrodegradable polymers undergo degradation reactions even during normal use, their usage environments are restricted. Conventional methods for decomposing urethane include amine decomposition, hydrolysis, alcohol decomposition, and acid decomposition (see Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2001-348457 [Patent Document 2] Japanese Patent Application Publication No. 11-080419 [Overview of the project] [Problems that the invention aims to solve]

[0004] Conventional polyurethanes had the problem of requiring a great deal of energy to decompose using methods such as amine decomposition. This invention addresses the above-mentioned problems and aims to provide a polymer that can be decomposed under mild conditions. [Means for solving the problem]

[0005] One aspect of the present invention is a polymer. The polymer is a polymer containing structural units represented by the following formula (1), wherein the polymer EO rate is defined as the polymer EO rate when the total amount of the polymer is 100% by mass, and the polymer EO rate is 10% or more. [Chemical formula] {In formula (1), R a is any one of a urethane bond, a urea bond, or a thiourethane bond. R 11 ~R 13 are each independently either hydrogen or a monovalent organic group.} In the polymer of the above aspect, the water absorption calculated from the following measurement method may be more than 1.0. (Measurement method) A test piece is prepared from the polymer. After measuring the mass A of the test piece, it is immersed in water. After 24 hours, the test piece is recovered, and after removing the water adhering to the surface, the mass B of the test piece is measured. The value obtained by dividing mass B by mass A is defined as the water absorption.

[0006] Another aspect of the present invention is an adhesive composition. The adhesive composition is formed by mixing a first liquid containing an isocyanate group-terminated urethane prepolymer and a second liquid containing a compound (A) having a structure represented by the following formula (2). When the content rate of ethylene oxide units in the total amount of the urethane prepolymer is defined as the urethane prepolymer EO rate, the urethane prepolymer EO rate is 11% or more. [Chemical formula] {In formula (2), R A , R B are each independently either a hydroxyl group, an amino group, or a thiol group. R 11 ~R 13 are each independently either hydrogen or a monovalent organic group. R1 is a divalent organic group.} In the adhesive composition of the above aspect, the urethane prepolymer is a urethane prepolymer obtained from a polyol and a polyisocyanate, and the polyisocyanate may contain diphenylmethane diisocyanate. [Advantages of the Invention]

[0007] According to the present invention, it is possible to provide a technique related to a polymer that can be decomposed under mild conditions.

Brief Description of Drawings

[0008] [Figure 1] It is a diagram showing the mechanism of the decomposition reaction of the polymer of the embodiment. [Figure 2] It is a diagram showing the flow of the production method S1 of the polymer of the embodiment. [Figure 3] It is a diagram showing the flow of the curing step S30 of the polymer of the embodiment.

Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail. In this specification, the notation "a to b" in the description of the numerical range represents a to b unless otherwise specified.

[0010] In the present disclosure, the number average molecular weight is measured using gel permeation chromatography (GPC) (for example, gel permeation chromatography according to ASTM standard test D5296) with polystyrene as the standard polymer.

[0011] (Polymer) The polymer according to the embodiment includes a structural unit represented by the following formula (1).

Chemical formula

[0012] In the polymer according to this embodiment, the polymer EO rate is defined as the polymer EO rate, where the polymer EO rate is 10% or more, based on the total amount of the polymer being 100% by mass. By having a polymer EO rate of 10% or more in the polymer according to this embodiment, the degradability can be improved. The polymer EO ratio can be adjusted by adjusting the EO ratio of the polyol compound described later, and consequently by adjusting the prepolymer EO ratio of the prepolymer.

[0013] The polymer in this embodiment preferably has a water absorption capacity greater than 1.0, as calculated by the measurement method described below. (Measurement method) Test specimens are prepared from the aforementioned polymer. After measuring the mass A of the test specimen, it is immersed in water. After 24 hours, the test specimen is collected, the water adhering to the surface is removed, and the mass B of the test specimen is measured. The water absorption value is calculated by dividing mass B by mass A.

[0014] As described above, the polymers of this embodiment include polyurethane, polyurea, or polythiourethane (urethane-based) polymers. Below, the physical properties of the polymers of this embodiment will be explained using polyurethane as a representative embodiment, but the polymers of this embodiment are not limited to polyurethane. The raw material composition and manufacturing method of the polymer will be explained in "2. Raw Material Composition / Manufacturing Method of Polymer" below.

[0015] <Physical properties / properties> (Decomposition performance) The polyurethane in this form undergoes a decomposition reaction through the decomposition method described later. In other words, the polyurethane in this form has decomposition properties under certain environmental conditions. The decomposition performance, i.e., the degree of decomposition reaction, can be evaluated by the gel fraction / decomposition rate described later. Furthermore, since the polyurethane in this form does not undergo a decomposition reaction under normal use at room temperature and pressure, it is superior to conventional biodegradable polymers in terms of physical, mechanical, and chemical properties. In addition, the decomposition process described later is performed under mild conditions and is a simple process, so it does not require high energy for decomposition.

[0016] (Disassembly process 1) In decomposition step 1, an oxidizing agent and a base are used, and the reaction proceeds in two steps (hereinafter sometimes referred to as the two-liquid, two-pot reaction). Add the solvent and oxidizing agent to the polyurethane and stir at room temperature for 1 to 20 hours. Remove the polyurethane, add the base solution, and stir at room temperature for 1 minute to 20 hours.

[0017] The solvent used in decomposition step 1 is not particularly limited, and any known solvent can be used. Examples include distilled water, acetonitrile, DMSO (dimethyl sulfoxide), and DMF (N,N-dimethylformamide).

[0018] In decomposition step 1, when the water absorption of polyurethane is greater than 1.0, the oxidizing agent and base permeate the polyurethane, making it easier for the base reaction to proceed in areas where the oxidation reaction has progressed, from the surface to the interior of the polyurethane, thus making the polyurethane more susceptible to decomposition.

[0019] (Decomposition mechanism) Figure 1 shows the mechanism of the decomposition reaction of polyurethane in this embodiment. As shown in Figure 1, when an oxidizing agent is added to polyurethane in this embodiment, the sulfur atoms of the thioether group are oxidized. Subsequently, when a basic aqueous solution is added and base treatment is performed, the polymer main chain of the polyurethane is cleaved and the decomposition reaction proceeds. At least a portion of the polyurethane after the decomposition reaction dissolves in the basic aqueous solution. Here, the decomposition mechanism of polyurethane in this embodiment has been described, but this decomposition mechanism is not limited to polyurethane in this embodiment. That is, this decomposition mechanism is similarly applicable to polyurea and polythiourethane.

[0020] The oxidizing agent is not particularly limited and includes hydrogen peroxide, OXONE® (potassium peroxymonosulfate), peracetic acid, sodium hypochlorite, sodium perborate, potassium permanganate, etc. The oxidizing agent must be added in an amount of 1 equivalent or more relative to the thioether group of the polyurethane in this form. The basic aqueous solution is not particularly limited and includes strong bases such as sodium hydroxide aqueous solution and potassium carbonate aqueous solution, and weak bases such as sodium carbonate aqueous solution.

[0021] (Gel fraction / Decomposition rate) Before and after the decomposition reaction using the above-described decomposition method, the mass of polyurethane is measured using the measurement method described later, and the gel fraction before and after the decomposition reaction is calculated. Furthermore, the decomposition rate is calculated from the gel fractions before and after the decomposition reaction. From the gel fraction and decomposition rate values, the degree of progress of the polyurethane decomposition reaction, i.e., the decomposition performance, can be evaluated.

[0022] (Method for measuring the mass of polyurethane) First, measure the mass of the polyurethane before performing the drying process described below. Then, perform the drying process as described below. Add tetrahydrofuran (THF) to the polyurethane and stir at room temperature for 20 hours. Remove the polyurethane, heat it to 50°C under vacuum to remove the tetrahydrofuran, and then dry it. The mass of the polyurethane after the drying treatment described above is measured.

[0023] (Method for calculating gel fraction / decomposition rate) The mass of polyurethane after drying, obtained by the measurement method described above, is divided by the mass of polyurethane before drying and multiplied by 100 to obtain the gel fraction. The decomposition rate is obtained by subtracting the gel fraction after decomposition from the gel fraction before decomposition and dividing the result by the gel fraction before decomposition. The formulas for calculating the gel fraction and decomposition rate are shown below. (Gel fraction) = (Mass after drying) / (Mass before drying) × 100 (Decomposition rate) = {(Gel fraction before decomposition) - (Gel fraction after decomposition)} / (Gel fraction before decomposition) × 100

[0024] The gel fraction before decomposition is not particularly limited; it is measured for the purpose of calculating the decomposition rate. The gel fraction after decomposition is preferably 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, or 15% or less. The decomposition rate is preferably 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, or 50% or more. By keeping the gel fraction and decomposition rate within the above ranges, the decomposition of polyurethane can be sufficiently advanced.

[0025] (Decomposition process 2) In decomposition step 2, oxidation and base reactions proceed continuously by using sodium hypochlorite (hereinafter sometimes referred to as a one-liquid-one-pot reaction). Add sodium hypochlorite solution to the polyurethane and stir at room temperature for 1 to 20 hours.

[0026] In decomposition step 2, oxidation and base reactions proceed sequentially from the surface of the polyurethane, allowing for efficient decomposition of the polyurethane regardless of its water absorption capacity. In the one-solution, one-pot reaction, an appropriate amount of acetonitrile may be added to the sodium hypochlorite aqueous solution.

[0027] This form of polyurethane, when manufactured by the manufacturing method (prepolymer method) described later, allows for control of the number-average molecular weight of the degradation products, thereby achieving the gel fraction and degradation rate within the above range. The number-average molecular weight of the degradation products is explained below.

[0028] (Adhesive composition) The adhesive composition according to the embodiment is obtained by mixing a first liquid containing an isocyanate group-terminated urethane prepolymer and a second liquid containing a compound (A) having the structure shown in the following formula (2). In the adhesive composition according to this embodiment, the urethane prepolymer EO rate is defined as the ethylene oxide unit content when the total amount of the urethane prepolymer is 100% by mass, and the urethane prepolymer EO rate is 11% or more. The urethane prepolymer EO rate can be adjusted by adjusting the EO rate of the polyol used as a raw material. [ka] {In formula (2), R A , R B Each of these is independently either a hydroxyl group, an amino group, or a thiol group. 11 ~R 13 Each of these is either hydrogen or a monovalent organic group. R1 is a divalent organic group. When the urethane prepolymer is obtained from a polyol and a polyisocyanate, it is preferable that the polyisocyanate is diphenylmethane diisocyanate.

[0029] 2-1. Raw material composition of polymers (polyurethane) The polymer (polyurethane) of this embodiment is obtained by polymerizing (curing) a raw material composition containing an isocyanate-terminated urethane prepolymer and a compound (A) having the structure shown in formula (2) below. The polyurethane of this embodiment may also contain other components in the raw material composition. The raw material composition of the polyurethane of this embodiment, consisting of the urethane prepolymer, compound (A), and other components, will be described below.

[0030] [ka]

[0031] In formula (2), R A , R B Each of these is independently either a hydroxyl group, an amino group, or a thiol group, and R 11 ~R 13 Each of these is either hydrogen or a monovalent organic group, while R1 is a divalent organic group.

[0032] <Urethane prepolymer> Urethane prepolymers are obtained by urethane reaction between a polyol compound and a polyisocyanate compound. In other words, urethane prepolymers are reaction products of polyol compounds and polyisocyanate compounds. More specifically, urethane prepolymers are usually synthesized by urethane reaction between a polyol compound and a polyisocyanate compound, with an excess of the polyisocyanate compound.

[0033] The number-average molecular weight of the urethane prepolymer is preferably 1,000 to 10,000, 1,100 to 5,000, or 1,200 to 3,000. By having the number-average molecular weight of the urethane prepolymer within the above range, a polyurethane with superior decomposition performance can be obtained.

[0034] The viscosity of the urethane prepolymer at 25°C is preferably within the ranges of 2,000 to 50,000 mPa·s, 2,000 to 40,000 mPa·s, 2,500 to 20,000 mPa·s, 3,000 to 10,000 mPa·s, or 3,500 to 6,000 mPa·s. By having the viscosity of the urethane prepolymer at 25°C within the above ranges, a polyurethane with superior decomposition performance can be obtained.

[0035] (Polyol compounds) A polyol compound is a compound having two or more hydroxyl groups in a single molecule. Polyol compounds are not particularly limited. Various polyols may be used individually or in combination of two or more. They can be freely selected considering the desired properties of the polyurethane.

[0036] The polyol compound preferably contains a copolymer of ethylene oxide (EO) and alkylene oxide (AO). Note that the alkylene oxide referred to here is other than ethylene oxide. The ethylene oxide (EO) content (EO ratio) in the polyol compound is adjusted so that the urethane prepolymer EO ratio is 11% and the polyurethane polymer EO ratio is 10% or more.

[0037] Examples of polyol compounds include polyester polyols, polycarbonate polyols, polyether polyols, and polyester ether polyols. These can be freely selected considering the desired properties of the polyurethane.

[0038] Examples of polyester polyols include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid; aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid; alicyclic dicarboxylic acids such as hexahydrophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid; or acid esters or acid anhydrides thereof, and ethylene glycol, 1,3-propylene glycol, and 1,2-propylene glycol. Examples include polyester polyols such as polypropylene glycol obtained by dehydration condensation reactions with 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, etc., or mixtures thereof; and polylactone diols obtained by ring-opening polymerization of lactone monomers such as ε-caprolactone and methylvalerolactone.

[0039] Examples of polycarbonate polyols include those obtained by reacting at least one polyhydric alcohol, such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, or diethylene glycol, with diethylene carbonate, dimethyl carbonate, diethyl carbonate, or the like.

[0040] Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and their copolyethers, which are obtained by polymerizing cyclic ethers such as ethylene oxide (EO), propylene oxide (PO), and tetrahydrofuran, respectively. They can also be obtained by polymerizing the above-mentioned cyclic ethers using polyhydric alcohols such as glycerin and trimethylolethane.

[0041] Examples of polyester ether polyols include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid; aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid; alicyclic dicarboxylic acids such as hexahydrophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid; or those obtained by dehydration condensation reactions of these acid esters or acid anhydrides with glycols such as diethylene glycol or propylene oxide adducts, or mixtures thereof. Polyol compounds can be used individually or in combination.

[0042] The polyol compound is preferably a diol and / or triol.

[0043] The polyol compound preferably has a number-average molecular weight of 200-5,000, 300-4,500, or 400-4,000. When the number-average molecular weight of the polyol is within this range, the number-average molecular weight of the urethane prepolymer is included within an appropriate range, thus enabling the production of a polyurethane with superior decomposition performance.

[0044] (Polyisocyanate compounds) A polyisocyanate compound is a compound having two or more isocyanate groups in a single molecule. It is not particularly limited as long as it is commonly used as a raw material for urethane prepolymers. A single polyisocyanate compound may be used alone or in combination of two or more. A polyisocyanate compound may be bifunctional or trifunctional or more. It can be freely selected considering the desired properties of the polyurethane.

[0045] Examples of bifunctional polyisocyanate compounds include 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), m-phenylenediisocyanate, p-phenylenediisocyanate, 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethanediisocyanate (2,4'-MDI), 2,2'-diphenylmethane diisocyanate (2,2'-MDI), hydrogenated MDI, xylylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylenediisocyanate, and 3,3'-dimethoxy-4,4'-biphenylenediisocyanate. Examples include aromatic compounds such as polymethylene polyphenyl polyisocyanate, 1,5-naphthalene diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, and tetramethylxylene diisocyanate (TMXDI); alicyclic compounds such as cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, and methylcyclohexane diisocyanate; and alkylene compounds such as butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropyl diisocyanate, methylene diisocyanate, and lysine diisocyanate.

[0046] Examples of polyisocyanate compounds with three or more functions include 1-methylbenzene-2,4,6-triisocyanate, 1,3,5-trimethylbenzene-2,4,6-triisocyanate, biphenyl-2,4,4'-triisocyanate, diphenylmethane-2,4,4'-triisocyanate, methyldiphenylmethane-4,6,4'-triisocyanate, 4,4'-dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate, triphenylmethane-4,4',4”-triisocyanate, polymeric MDI, lysine ester triisocyanate, 1,3,6-hexamethylene triisocyanate, 1,6,11-undecane triisocyanate, bicycloheptane triisocyanate, and 1,8-diisocyanatomethyloctane.

[0047] Furthermore, polyisocyanate compounds may include modified forms, derivatives, etc.

[0048] Polyisocyanate compounds can be used individually or in combination.

[0049] <Compound (A)> Compound (A) has the structure shown in formula (2) below. [ka]

[0050] In formula (2), R A , R B Each of these is independently an active hydrogen group (either a hydroxyl group, an amino group, or a thiol group), and R 11 ~R 13 Each of these is either hydrogen or a monovalent organic group, while R1 is a divalent organic group.

[0051] As shown in formula (2) above, compound (A) has a molecular chain terminal (R A , R B ) has an active hydrogen group that can react with an isocyanate group. Compound (A) preferably contains a thioether group.

[0052] end of molecular chain (R A , R B Examples of active hydrogen groups include hydroxyl groups, amino groups, and thiol groups. Preferably, hydroxyl groups and amino groups are used, and more preferably, hydroxyl groups. The end of the molecular chain (R A , R B ) may be the same type of functional group or a combination of different types of functional groups. Furthermore, a primary amino group is preferred for the amino group. Additionally, compound (A) has terminal (R) of the molecular chain. A , R B The compound (A) may also have active hydrogen groups in parts other than those specified. That is, compound (A) may have three or more active hydrogen groups.

[0053] R1 is not particularly limited as long as it is a divalent organic group, but is preferably a hydrocarbon group having 1 to 19 carbon atoms, more preferably 1 to 10 carbon atoms, even more preferably 1 to 5 carbon atoms, and most preferably 2 carbon atoms.

[0054] R 11 ~R 13 The group is not particularly limited as long as it is hydrogen or a monovalent organic group, but is preferably hydrogen or a hydrocarbon group having 1 to 5 carbon atoms, and more preferably hydrogen.

[0055] R in compound (A) A The number of carbon atoms per sulfur atom bonded to -CC- and R1 is preferably 2 or more, 3 or more, and preferably 7 or less, 4 or less.

[0056] More specifically, compound (A) includes compounds containing a hydroxyl-terminated thioether group, compounds containing an amino-terminated thioether group, and compounds containing a thiol-terminated thioether group.

[0057] Compounds containing hydroxyl-terminated thioether groups have a molecular chain terminal (R A , R B It has a hydroxyl group and a thioether group in the middle of the molecular chain. Examples of compounds containing a hydroxyl-terminated thioether group include 2,2'-thiodiethanol (TDE).

[0058] A compound containing an amino group-terminated thioether group has a molecular chain terminal (R A , R B It has an amino group and a thioether group in the middle of the molecular chain. Examples of amino-terminated thioether-containing compounds include bis(2-aminoethyl) sulfide.

[0059] Thiol-terminated thioether-containing compounds have a thiol-terminated (R) at the end of the molecular chain. A , R BIt has a thiol group at the base of the molecule and a thioether group in the middle of the molecular chain. Examples of compounds containing a thiol-terminated thioether group include bis(2-mercaptoethyl) sulfide (MES).

[0060] The content of compound (A) is preferably 1% by mass or more, 5% by mass or more, 10% by mass or more, based on the mass of the urethane prepolymer, and is also preferably 25% by mass or less, 20% by mass or less, 15% by mass or less.

[0061] The molecular weight of compound (A) is preferably, for example, 50 or more, 60 or more, or 100 or more, and also preferably 500 or less, 400 or less, or 300 or less.

[0062] The sulfide concentration in 1 kg of polyurethane in this embodiment is preferably 0.1 mol / kg or more, 0.2 mol / kg or more, 0.3 mol / kg or more, and preferably 0.9 mol / kg or less, 0.85 mol / kg or less, 0.8 mol / kg or less. The method for calculating the sulfide concentration is described below.

[0063] (Method for calculating sulfide concentration) The amount of compound (A) added and the total amount of all components in the polyurethane in this form are used to calculate the compound (A) content P in 1 kg of polyurethane. This compound (A) content P is then divided by the molecular weight Q of compound (A) to calculate the sulfide concentration in 1 kg of polyurethane. The formula for calculating the sulfide concentration is shown below. (Sulfide concentration) = {Content of compound (A) P} / {Molecular weight of compound (A) Q} (mol / kg)

[0064] In addition, the polyurethane raw material composition of this embodiment may contain another compound (B) other than compound (A), as long as the amount of compound (A) and the sulfide concentration are within the range described above. Compound (B) is not particularly limited as long as it is a compound that can polymerize with the urethane prepolymer, and examples include diethylene glycol and 1,5-pentanediol.

[0065] <Other ingredients> Other components that may be appropriately added to the polyurethane raw material composition in this form include defoaming agents, catalysts, and the like.

[0066] (Antifoaming agent) For example, fatty acid esters, petrolatum, etc., can be used as defoaming agents. One of these foam stabilizers / defoaming agents may be used, or two or more may be used in combination.

[0067] (catalyst) The catalysts include tertiary amines {C6-20, e.g., triethylamine, triethylenediamine, bis(dimethylaminoethyl) ether, N-methylmorpholine, dimethylaminomethylphenol, N-methyl-N-dimethylaminoethylpiperazine, pyridine, etc.}, and their acid-blocking compounds, metal salts of carboxylic acids (C2-20) (sodium acetate, lead octylate, zinc octylate, iron octylate, bismuth octylate, zinc neodecanoate, iron naphthenate, cobalt naphthenate, stanus octoate, dibutyltine dilaurate, etc.), alkali metals or Examples include alkaline earth metal alkoxides or phenoxides (C1-C12, e.g., sodium methoxide, sodium phenoxide), quaternary ammonium salts (C4-C12, e.g., tetraethylhydroxylammonium), imidazole compounds (C3-C12, e.g., imidazole, 2-ethyl-4-methylimidazole), chelate metal salts (C5-C20, e.g., zinc acetylacetone, iron acetylacetone), and organometallic compounds containing metals such as tin and antimony (C3-C30, e.g., tetraphenyltin, tributylantimony oxide). These catalysts can be used alone or in combination.

[0068] 2-2. Method for producing polymers (polyurethane) This form of polymer (polyurethane) can be manufactured based on the prepolymerization method. This prepolymerization method involves pre-reacting a polyol compound with a polyisocyanate compound to obtain a prepolymer having isocyanate groups at its ends (the urethane prepolymer described above), and then reacting it with compound (A).

[0069] Figure 2 shows the flow of the polyurethane manufacturing method of this embodiment. As shown in Figure 2, the polyurethane manufacturing method S1 of this embodiment includes a urethane prepolymer manufacturing step S10, a raw material composition preparation step S20, and a curing step S30. The preferred method S1 for manufacturing polyurethane of this embodiment will be described below, divided into each step.

[0070] 2-2-1. Manufacturing process of urethane prepolymer S10 A predetermined amount of polyol compound and, if necessary, a catalyst are added dropwise to a reaction vessel containing a predetermined amount of polyisocyanate compound. The reaction vessel is then heated and stirred to react the polyisocyanate compound with the polyol compound, thereby producing an isocyanate-terminated urethane prepolymer. The reaction temperature is not particularly limited, but is usually 50 to 120°C, preferably 60 to 100°C. The reaction time is not particularly limited, but is usually 1 to 15 hours.

[0071] Polyol compounds, polyisocyanate compounds, etc., are as described above under (Polyol Compounds) and (Polyisocyanate Compounds).

[0072] (catalyst) The catalyst can be one of the known catalysts used in the production of polyurethane. Examples include amine-based catalysts and organometallic catalysts.

[0073] Examples of amine-based catalysts include triethylenediamine, diethanolamine, dimethylaminomorpholine, and N-ethylmorpholine.

[0074] Examples of organometallic catalysts include bismuth carboxylate, sternal octoate, dibutylthin dilaurate, lead octoate, and potassium octoate.

[0075] Catalysts can be used individually or in combination.

[0076] 2-2-2. Preparation process of raw material composition S20 The raw material composition preparation step S20 involves preparing a raw material composition containing a urethane prepolymer and, as compound (A), for example, 2,2'-thiodiethanol. The raw material composition may optionally contain other components (catalysts, defoamers, etc.). The urethane prepolymer, compound (A), and other components are as described in "2-1. Raw Material Composition for Polymers (Polyurethane)" above.

[0077] 2-2-3.Curing process S30 Figure 3 shows the flow of the curing process S30. As shown in Figure 3, the curing process S30 includes mixing and stirring the raw material composition prepared in the raw material composition preparation process S20 (stirring step S31), making a film from the raw material composition using a coating jig such as a bar coater (film making step S32), and, if necessary, heating the film to complete the polymerization (curing) reaction and produce polyurethane (reaction step S33). The curing process S30 will be described below in detail for each step.

[0078] (Agitation step S31) In the stirring step S31, the urethane prepolymer, compound (A), and other components such as catalysts and defoamers, prepared in the raw material composition preparation step S20, are placed in a container such as a disposable cup and stirred so that each component is uniformly mixed. The stirring step S31 can be carried out using known stirring means such as a mixer. The stirring conditions in the stirring step S31 should be appropriately selected according to the viscosity and components to be blended.

[0079] (Film production step S32) In the film production step S32, a film is produced from the raw material composition mixed in the stirring step S31 using a coating jig such as a bar coater. By adjusting the amount of raw material composition applied, a film of a desired thickness can be produced.

[0080] (Reaction step S33) In reaction step S33, the film prepared in film preparation step S32 is heated and cured. The curing reaction is usually carried out at a temperature of 15 to 120°C, preferably 15 to 90°C. The reaction time is usually 60 to 120 minutes.

[0081] A drying step may be performed on the cured product obtained in reaction step S33, if necessary. The drying step may involve exposing the polyurethane to an environment of 80-120°C using, for example, a heating furnace, microwave oven, high-frequency induction heating, or hot air drying.

[0082] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted. [Examples]

[0083] The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0084] (Urethane prepolymer) Terminal NCO urethane prepolymers (prepolymers 1-5) were synthesized using the raw materials and proportions shown in Table 1. [Table 1] *The amounts in Table 1 are shown in mass percent. Details of each ingredient listed in Table 1 are as follows: MI (m-MDI): Diphenylmethane diisocyanate (NCO%: 33.6%, 2 functional groups) Polyol 1: Manufactured by Sanyo Chemical Industries, Ltd., GP-1000, EO content (mass%) 0% Polyol 2: Manufactured by NOF Corporation, Unilube 75DE-15, EO content (mass%) 75% Polyol 3: Manufactured by Mitsui Chemicals, Actcol D-1000, EO content (mass%) 0% Polyol 4: Manufactured by Toho Chemical Industry Co., Ltd., PEG #1000, EO content (mass%) 100%

[0085] (Examples and Comparative Examples) As shown in Table 2, each raw material (isocyanate-terminated urethane prepolymer, catalyst, defoamer, and thiodiethanol) was weighed into a disposable cup, stirred for 1 minute with a mechanical stirrer, and then degassed under vacuum. Next, it was cast onto a release film and coated with a bar coater. After curing at 70°C for 20 hours, an adhesive film with a thickness of 250 μm was obtained. [Table 2] Details of each ingredient listed in Table 2 are as follows: Antifoaming agent: Dappo® SN348, manufactured by Sunopco Co., Ltd. Catalyst: TIB Chemical Co., Ltd., TIB KAT616 Zinc Neodecanoate All adhesive films had an isocyanate index (INDEX) of 100. The isocyanate index is the ratio of the number of moles of isocyanate groups in an isocyanate compound (isocyanate-terminated urethane prepolymer) to the number of moles of thiodiethanol or diethylene glycol.

[0086] <Sulfide concentration> The amount of thiodiethanol used to synthesize 1 kg of urethane polymer was estimated from the amount of thiodiethanol added in the formulations of each example and comparative example, and the total amount added. Specifically, the amount of thiodiethanol used (content) was divided by the molecular weight of thiodiethanol to calculate the sulfide concentration (mol / kg) in 1 kg of urethane polymer.

[0087] <Crosslinking degree> The number of moles of trifunctional PPG used in the synthesis of terminal NCO urethane prepolymer was estimated. Next, the degree of crosslinking (mol / kg) in the urethane polymer was calculated by multiplying the number of moles of trifunctional PPG used in the synthesis of terminal NCO urethane prepolymer by the mass ratio of terminal NCO prepolymer used when synthesizing 1 kg of urethane polymer.

[0088] <Water absorption> The water absorption was measured using the following measurement method. (Measurement method) A test specimen (the aforementioned adhesive film with a thickness of 250 μm) is prepared from the polymer. After measuring the mass A of the test specimen, it is immersed in water. After 24 hours, the test specimen is collected, the water adhering to the surface is removed, and the mass B of the test specimen is measured. The water absorption value is calculated by dividing mass B by mass A.

[0089] <Decomposition Experiment 1 (Two-Liquid, Two-Pod Reaction)> 0.045 g of urethane polymer (the adhesive film mentioned above) was measured into a 20 ml vial, and 3 equivalents of OXONE® and 9 g of distilled water were added relative to the sulfide molecules. After stirring at room temperature with a roller stirrer for 20 hours, the urethane polymer was removed, transferred to a vial, and 9 g of 1 mol / L NaOH aqueous solution was added, and the mixture was stirred at room temperature with a roller stirrer for 20 hours. The urethane polymer was removed, transferred to a vial, and 9 g of THF was added, and the mixture was stirred at room temperature with a roller stirrer for 20 hours. The urethane polymer was removed, and the THF was removed by distillation while heating in a vacuum dryer at 50°C. Following the procedure described above, the gel fraction before the decomposition experiment (initial gel fraction), the gel fraction after the decomposition experiment (post-treatment gel fraction), and the decomposition rate were calculated. The results are shown in Table 3.

[0090] [Table 3]

[0091] <Decomposition Experiment 2 (1-liquid, 1-pod reaction)> 0.045 g of urethane polymer (the adhesive film mentioned above) was measured into a 20 ml vial, and sodium hypochlorite (0.3% by mass aqueous solution (0.03 g sodium hypochlorite), 10% by mass aqueous solution (1.0 g sodium hypochlorite)) and 9 g of distilled water were added. After stirring at room temperature with a roller stirrer for 20 hours, the urethane polymer was removed, transferred to a vial, 9 g of THF was added, and the mixture was stirred at room temperature with a roller stirrer for 20 hours. The urethane polymer was removed, and the THF was removed by distillation while heating in a vacuum dryer to 50°C. Following the procedure described above, the gel fraction before the decomposition experiment (initial gel fraction), the gel fraction after the decomposition experiment (treated gel fraction), and the decomposition rate were calculated. The results are shown in Table 4.

[0092] [Table 4]

[0093] <Decomposition Experiment 3 (1-solution, 1-pot reaction + solvent combination)> For adhesive film formulations with water absorption less than 1.1 times, decomposition was insufficient even with a 10 wt% sodium hypochlorite aqueous solution. Therefore, a mixed solvent containing a solvent and water was used to swell the adhesive film and facilitate decomposition. Comparative Examples 1 (0% polymer EO) and 2 (9% polymer EO), which had low decomposition rates, were used. Acetonitrile was used as a solvent in combination. The results obtained are shown in Table 5.

[0094] [Table 5]

[0095] As shown in Table 5, under the condition of water / acetonitrile = 9 / 1, the water absorption rate became 1.1, confirming a significant improvement in degradability. [Industrial applicability]

[0096] Because the polymers of this disclosure are easily decomposed, they can be used as environmentally friendly adhesives.

Claims

1. A polymer containing the structural unit shown in the following formula (1), A polymer in which, when the total amount of the polymer is taken as 100% by mass, the polymer EO rate is defined as the content of ethylene oxide units, and the polymer EO rate is 10% or more. 【Chemistry 1】 {In formula (1), R ａ This is either a urethane bond, a urea bond, or a thiourethane bond. １１ ~R １３ Each of these is independently either hydrogen or a monovalent organic group.

2. The polymer according to claim 1, wherein the water absorption capacity calculated by the measurement method described below is greater than 1.

0. (Measurement method) Test specimens are prepared from the aforementioned polymer. After measuring the mass A of the test specimen, it is immersed in water. After 24 hours, the test specimen is collected, the water adhering to its surface is removed, and then the mass B of the test specimen is measured. The water absorption value is calculated by dividing mass B by mass A.

3. A first liquid containing an isocyanate-terminated urethane prepolymer, A second solution containing compound (A) having the structure shown in formula (2) below is mixed with the following: An adhesive composition in which, when the total amount of the urethane prepolymer is taken as 100% by mass, the ethylene oxide unit content is defined as the urethane prepolymer EO rate, and the urethane prepolymer EO rate is 11% or more. 【Chemistry 2】 {In formula (2), R Ａ , R Ｂ Each of these is independently either a hydroxyl group, an amino group, or a thiol group. １１ ~R １３ Each of these is independently either hydrogen or a monovalent organic group. １ It is a divalent organic group.

4. The urethane prepolymer is a urethane prepolymer obtained from a polyol and a polyisocyanate, The adhesive composition according to claim 3, wherein the polyisocyanate comprises diphenylmethane diisocyanate.

Images