WO2022075300A1

WO2022075300A1 - Crosslinked product

Info

Publication number: WO2022075300A1
Application number: PCT/JP2021/036758
Authority: WO
Inventors: 俊幸船山; 和樹宇野; 友訓原田
Original assignee: 株式会社大阪ソーダ
Priority date: 2020-10-06
Filing date: 2021-10-05
Publication date: 2022-04-14
Also published as: JPWO2022075300A1; TW202222970A

Abstract

For a crosslinked product using a polyether polymer, it is difficult to improve the heat resistance, oil resistance, etc. beyond the current state; and the present invention addresses the problem of further improving the heat resistance, oil resistance, etc. of a crosslinked product using a polyether polymer. It has been discovered that a crosslinked product using a polyether polymer and a polymethacrylic acid methyl resin has outstanding heat resistance and oil resistance when there is a specific relationship between the content ratio of the polymethacrylic acid methyl resin in a composition containing the polymethacrylic acid methyl resin and the polyether polymer for the crosslinked product, and the extraction ratio when subjecting the crosslinked product to Soxhlet extraction using acetone as the solvent.

Description

Cross-linked product

The present invention relates to a crosslinked product using a polyether polymer and a polymethyl methacrylate resin.

Rubber materials using polyether polymers are widely used as fuel hoses, air hoses, and tube materials in automobile applications, taking advantage of their heat resistance, oil resistance, ozone resistance, etc. However, in recent years, with the implementation of exhaust gas regulation measures and energy saving measures, the temperature rise in the engine room due to higher performance and compactness of the engine, and the maintenance-free operation of automobile parts, there is a demand for improvement of heat resistance of rubber materials. Is getting tougher year by year.

It should be noted that organic nickel compounds, particularly nickel dibutyldithiocarbamate, have been widely used as an effective antiaging agent capable of improving heat resistance and ozone resistance even in a polyether polymer such as epihalohydrin-based rubber.

The applicant discloses that the heat resistance is improved by adding a copper salt of dithiocarbamic acid to a polyether polymer such as epihalohydrin-based rubber (see Patent Document 1).

Patent No. 5239865

However, it is difficult to improve the heat resistance, oil resistance, etc. of the crosslinked product using the polyether polymer, and the crosslinked product using the polyether polymer has further heat resistance, oil resistance, etc. The challenge is to improve.

In the crosslinked product using the polyether polymer and the polymethylmethacrylate resin, the present inventors have made the polymethylmethacrylate in the composition containing the polyether polymer for the crosslinked product and the polymethylmethacrylate resin. It has been found that when the relationship between the resin content ratio and the extraction ratio when the crosslinked product is soxley-extracted using acetone as a solvent has a certain relationship, it has excellent heat resistance and oil resistance.

The present invention can also be described as follows.
Item 1 A crosslinked product prepared from a rubber composition containing (a) a polyether-based polymer, (b) a polymethyl methacrylate resin, and (c) a cross-linking agent.
When the mass of the rubber composition is A and the mass of (b) polymethylmethacrylate resin in the rubber composition is B, B / A and the crosslinked product (mass X) are used as a solvent for soxley extraction at 78 ° C. 6 A crosslinked product in which Y / X satisfies the following formula (1) when the extraction amount (mass Y) after the time is changed.
0.10 ≤ (Y / X) / (B / A) ≤ 0.90 (1)
Item 2 The crosslinked product according to Item 1, wherein the (a) polyether-based polymer contains at least one unit selected from ethylene oxide, propylene oxide, epichlorohydrin, and allyl glycidyl ether as a constituent unit.

Since the crosslinked product of the present invention has excellent heat resistance and oil resistance, it can be widely applied to fields in which heat-resistant and oil-resistant synthetic rubber is used. For example, it is useful as a rubber material for various fuel-based laminated hoses for automobiles, air-based laminated hoses, tubes, belts, diaphragms, seals, etc., and rubber materials for general industrial equipment / devices.

The present invention will be described in detail below.

The crosslinked product of the present invention is a crosslinked product prepared from a rubber composition containing (a) a polyether polymer, (b) a polymethyl methacrylate resin, and (c) a cross-linking agent.
When the mass of the rubber composition is A and the mass of (b) polymethylmethacrylate resin in the rubber composition is B, B / A and the crosslinked product (mass X) are used as a solvent for soxley extraction at 78 ° C. 6 It is a crosslinked product in which Y / X satisfies the following formula (1) when the extraction amount (mass Y) after the time is changed. As a result, excellent heat resistance and oil resistance can be obtained.
0.10 ≤ (Y / X) / (B / A) ≤ 0.90 (1)

Although the above-mentioned crosslinked product has the above-mentioned effect, the reason why such an action effect is obtained is not always clear, but it is presumed as follows.
In the rubber composition for producing the crosslinked product, the acetone extraction content of the rubber crosslinked product is reduced by using (a) a polyether polymer and (b) a polymethyl methacrylate resin in combination and applying shearing at a high temperature. This suggests the formation of a chemical bond between the domains of (a) the polyether polymer and (b) the polymethyl methacrylate resin. Therefore, in the present invention, in the rubber composition for producing a crosslinked product, (a) a polyether polymer and (b) a polymethyl methacrylate resin are used in combination, and mechanical shearing is applied at a high temperature to obtain ((a). It is speculated that such an effect is exhibited by the formation of a chemical bond between a) a polyether polymer and (b) a polymethylmethacrylate resin domain.
When the mass of the rubber composition is A and the mass of the (b) polymethylmethacrylate resin in the rubber composition is B, the B / A is the mass ratio of the (b) polymethylmethacrylate resin in the rubber composition. show. Therefore, the larger the B / A, the larger the mass ratio of the (b) polymethylmethacrylate resin in the rubber composition.
On the other hand, Y / X when the crosslinked product (mass X) is the extraction amount (mass Y) after soxley extraction is performed at 78 ° C. for 6 hours using acetone as a solvent indicates the mass ratio of the acetone extract in the crosslinked product. .. Here, it is presumed that the acetone extract is a relatively low molecular weight component that is not involved in cross-linking in the cross-linked product. Therefore, the smaller the Y / X, the higher the crosslink density.
(Y / X) / (B / A) indicates the amount of the uncrosslinked component in the crosslinked product with respect to the amount of the (b) polymethylmethacrylate resin component in the rubber composition, and (a) the polyether-based polymer. -(B) Means the amount of chemical bond between the domains of the polymethyl methacrylate resin. When (Y / X) / (B / A) is large, there are many uncrosslinked components in the crosslinked product with respect to the amount of (b) polymethylmethacrylate resin, that is, (a) the polyether polymer and (b). ) It means that the amount of chemical bond between the domains of the polymethylmethacrylate resin is small, and when (Y / X) / (B / A) is small, the (b) polymethylmethacrylate resin in the rubber composition It means that the amount of uncrosslinked components in the crosslinked product is small relative to the amount, that is, the amount of chemical bond between the domains of (a) the polyether polymer and (b) the polymethyl methacrylate resin is large.
Therefore, satisfying the above formula (1) forms a chemical bond in the crosslinked product between the domains of (a) the polyether polymer and (b) the polymethyl methacrylate resin, which contributes to the improvement of physical properties. Means that you are. Therefore, excellent heat resistance and oil resistance can be obtained by satisfying the above formula (1).

The crosslinked product of the present invention is produced from a rubber composition containing (a) a polyether polymer, (b) a polymethyl methacrylate resin, and (c) a crosslinking agent.

The (a) polyether-based polymer in the rubber composition of the present invention includes alkylene oxides such as ethylene oxide, propylene oxide and n-butylene oxide, methyl glycidyl ether, ethyl glycidyl ether, n-glycidyl ether and allyl glycidyl ether. It is preferably a polymer obtained by polymerizing a compound selected from glycidyls such as phenylglycidyl ether, epihalohydrins such as epichlorohydrin and epibromhydrin, and styrene oxide, and is preferably a polymer obtained by polymerizing ethylene oxide, propylene oxide, etc. It is preferably a polymer obtained by polymerizing a compound selected from epichlorohydrin and allylglycidyl ether, and most preferably at least epichlorohydrin is contained in the constituent unit. (A) The polyether-based polymer may be used alone or in combination of two or more.

The polyether polymer preferably has 20 mol% or more of epichlorohydrin-based structural units, more preferably 30 mol% or more, particularly preferably 40 mol% or more, and may have 100 mol% or less, 90 mol. % Or less, 80 mol% or less, and 75 mol% or less.

The polyether polymer preferably has 10 mol% or more of the structural unit based on ethylene oxide, more preferably 20 mol% or more, particularly preferably 25 mol% or more, preferably 80 mol% or less, and 70 mol% or less. It is more preferable to have it, and it is particularly preferable to have it in an amount of 60 mol% or less.

The total of the building blocks based on ethylene oxide and the building blocks based on epichlorohydrin is preferably 90 mol% or more, more preferably 93 mol% or more, and particularly preferably 97 mol% or more. ..

The polyether polymer may have 1 mol% or more of structural units based on allyl glycidyl ether, 2 mol% or more, 3 mol% or more, and 15 mol% or less. It may have 10 mol% or less, and may have 7 mol% or less.

When the polyether polymer of the present invention uses epichlorohydrin, alkylene oxide, or allylglycidyl ether as a monomer species, the polymerization composition is determined by the chlorine content and iodine value.
Chlorine content is measured by potentiometric titration according to the method described in JIS K7229. From the obtained chlorine content, the mole fraction of the constituent unit based on epichlorohydrin is calculated.
The iodine value is measured by a method according to JIS K6235. From the obtained iodine value, the mole fraction of the constituent unit based on allyl glycidyl ether is calculated.
The mole fraction of the constituent unit derived from alkylene oxide is calculated from the mole fraction of the constituent unit based on epichlorohydrin and the molar fraction of the constituent unit based on allylglycidyl ether.

In the polyether polymer of the present invention, the weight average molecular weight of the polymer used is not particularly limited, but the lower limit of the weight average molecular weight is preferably 200,000 or more, more preferably 300,000 or more, and the weight. The upper limit of the average molecular weight is preferably 3 million or less, more preferably 2 million or less.

As a method for producing a random polymer of a polyether polymer, a material capable of ring-opening polymerization of an oxylan compound is used as a catalyst, and the monomer can be polymerized. The polymerization temperature is, for example, in the range of −20 to 100 ° C. This polymerization may be either solution polymerization or slurry polymerization. The catalysts include, for example, a catalyst system mainly composed of organic aluminum in which an oxo acid compound of water or phosphorus or acetylacetone is reacted, a catalyst system mainly composed of organic zinc in which water is reacted, and organic tin-phosphorus. Examples thereof include an acid ester condensate catalyst system.

The polymethylmethacrylate resin (b) of the present invention is a homopolymer of a methyl methacrylate monomer (methyl methacrylate monomer) or a copolymer of a methyl methacrylate monomer and an acrylic acid ester monomer. However, other monomers may be copolymerized. In the case of the copolymer, it is preferable to contain a structural unit based on methyl methacrylate in an amount of 80% by mass or more. (B) The polymethyl methacrylate resin may be used alone or in combination of two or more.

Examples of the acrylic acid ester monomer include methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, and (meth) acrylic acid. Benzyl, cyclohexyl (meth) acrylate and the like can be exemplified.

Examples of other monomers include nitrile-based monomers such as acrylonitrile and methacrylonitrile, and maleimide-based monomers such as maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide. ..

The method for producing the polymethyl methacrylate resin is not particularly limited, and known emulsification polymerization methods, suspension polymerization methods, bulk polymerization methods, solution polymerization methods and the like can be exemplified.

As the polymethylmethacrylate resin of the present invention, commercially available ones can be used, for example, the product name: Parapet series (manufactured by Kuraray Co., Ltd.) and the product name: Acrypet series (manufactured by Mitsubishi Rayon Co., Ltd.) are used. can do.

(B) The bicut softening temperature of the polymethyl methacrylate resin is preferably 80 ° C. or higher, more preferably 90 ° C. or higher, still more preferably 95 ° C. or higher, preferably 130 ° C. or lower, more preferably 120 ° C. or lower, and further. It is preferably 115 ° C. or lower.
In the present specification, the Vicat softening temperature is measured according to JIS K7206.

The mass ratio of the (a) polyether-based polymer and (b) polymethylmethacrylate resin in the rubber composition of the present invention is 85: between (a) the polyether-based polymer and (b) the polymethylmethacrylate resin. It is preferably 15 to 30:70, more preferably 80:20 to 40:60, and particularly preferably 75:25 to 50:50.

The total content of (a) the polyether polymer and (b) the polymethyl methacrylate resin in 100% by mass of the rubber composition of the present invention is preferably 45% by mass or more, more preferably 50% by mass or more, and further. It is preferably 60% by mass or more, preferably 90% by mass or less, more preferably 80% by mass or less, and further preferably 70% by mass or less.

Examples of the (c) cross-linking agent of the present invention include known cross-linking agents that utilize the reactivity of chlorine atoms and known cross-linking agents that utilize the reactivity of side chain double bonds. Known cross-linking agents that utilize the reactivity of chlorine atoms include polyamine-based cross-linking agents, thiourea-based cross-linking agents, thiadiazol-based cross-linking agents, mercaptotriazine-based cross-linking agents, pyrazine-based cross-linking agents, quinoxalin-based cross-linking agents, and bisphenol-based cross-linking agents. As a known cross-linking agent utilizing the reactivity of the side chain double bond, a sulfur-based cross-linking agent and an organic peroxide-based cross-linking agent can be exemplified. (C) The cross-linking agent may be used alone or in combination of two or more. Of these, a quinoxaline-based cross-linking agent is preferable.

Examples of the polyamine-based cross-linking agent include ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenetetramine, p-phenylenediamine, cumendiamine, N, N,'-dicinnamilyden-1,6-hexanediamine, ethylenediamine carbamate, and hexane. Examples include methylenediamine carbamate.

Examples of the thiourea-based cross-linking agent include ethylene thiourea, 1,3-diethyl thiourea, 1,3-dibutyl thiourea, and trimethyl thiourea.

Examples of the thiadiazole-based cross-linking agent include 2,5-dimercapto-1,3,4-thiadiazole, 2-mercapto-1,3,4-thiadiazole-5-thiobenzoate and the like.

Examples of the mercaptotriazine-based cross-linking agent include 2,4,6-trimercapto-1,3,5-triazine, 2-hexylamino4,6-dimercaptotriazine, 2-diethylamino-4,6-dimercaptotriazine, 2 -Cyclohexylamino-4,6 dimercaptotriazine, 2-dibutylamino-4,6-dimercaptotriazine, 2-anilino-4,6-dimercaptotriazine, 2-phenylamino-4,6-dimercaptotriazine, etc. can give.

Examples of the pyrazine-based cross-linking agent include 2,3-dimercaptopyrazine derivatives, and examples of 2,3-dimercaptopyrazine derivatives include pyrazine-2,3-dithiocarbonate and 5-methyl-2,3-di. Examples thereof include mercaptopyrazine, 5-ethylpyrazine-2,3-dithiocarbonate, 5,6-dimethyl-2,3-dimercaptopyrazine, 5,6-dimethylpyrazine-2,3-dithiocarbonate and the like.

Examples of the quinoxaline-based cross-linking agent include 2,3-dimercaptoquinoxaline derivatives, and examples of 2,3-dimercaptoquinoxaline derivatives include quinoxaline-2,3-dithiocarbonate and 6-methylquinoxaline-2,3-. Examples thereof include dithiocarbonate (quinomethionate), 6-ethyl-2,3-dimercaptoquinoxaline, 6-iopropylquinoxaline-2,3-dithiocarbonate, 5,8-dimethylquinoxaline-2,3-dithiocarbonate and the like.

Examples of the bisphenol-based cross-linking agent include 4,4-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfone (bisphenol S), 1,1-cyclohexylidene-bis (4-hydroxybenzene), 2-chloro-1, 4-Cyclohexylene-bis (4-hydroxybenzene), 2,2-isopropyridene-bis (4-hydroxybenzene) (bisphenol A), hexafluoroisopropyrine-bis (4-hydroxybenzene) (bisphenol AF), and Examples thereof include 2-fluoro-1,4-phenylene-bis (4-hydroxybenzene).

Sulfur-based cross-linking agents include sulfur, morpholine disulfide, tetramethylthium disulfide, tetraethylthium disulfide, tetrabutyltiuram disulfide, N, N'-dimethyl-N, N'-diphenylthiuram disulfide, dipentanemethylenetiuram tetrasulfide, and disulfide. Examples thereof include pentamethylene thiuram tetrasulfide and dipentamethylene thiuram hexasulfide.

Examples of the organic peroxide-based cross-linking agent include tert-butyl hydroperoxide, 1,1,3,3, -tetramethylbutylhydroperoxide, cumenehydroperoxide, diisopropylbenzenehydroperoxide, di-tert-butyl peroxide, and dicumyl peroxide. , Tert-butylcumyl peroxide, 1,1-tert-butylperoxycyclohexane, 2,5-dimethyl-2,5-ditert-butylperoxyhexane, 2,5-dimethyl-2,5-ditertdibutylperoxyhe Xin-3,1,3-bisstart-butylperoxyisopropylbenzene, 2,5-dimethyl-2,5-dibenzoylperoxyhexane, 1,1-bisstart-butylperoxy-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis tert-butylperoxyvalerate, benzoyl peroxide, tert-butyl peroxide isobutyrate, tert-butylperoxy2-ethylhexanoate, tert-butylperoxybenzoate, tert-butylperoxyisopropylcarbo Examples include nat, tert-butylperoxyallyl monocarbonate, and p-methylbenzoyl peroxide.

The blending amount of the cross-linking agent is preferably 0.1 to 20 parts by mass, preferably 0 to 20 parts by mass when the total of (a) the polyether polymer and (b) the polymethyl methacrylate resin is 100 parts by mass. .2 to 10 parts by mass is more preferable, and 0.3 to 5 parts by mass is particularly preferable.

Further, a known accelerator (that is, a crosslinking accelerator) used together with a crosslinking agent can be used as it is in the rubber composition of the present invention.

Examples of the cross-linking accelerator include thiuram-based cross-linking accelerator, thiazole-based cross-linking accelerator, morpholine sulfide-based cross-linking accelerator, sulfenamide-based cross-linking accelerator, guanidine-based cross-linking accelerator, thiourea-based cross-linking accelerator, and aldehyde-. Ammonia-based cross-linking accelerator, dithiocarbamate-based cross-linking accelerator, xanthogenate-based cross-linking accelerator, fatty acid alkali metal salt-based cross-linking accelerator, 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) Omitted) Salt-based cross-linking accelerator, 1,5-diazabicyclo (4,3,0) Nonen-5 (hereinafter abbreviated as DBN) salt-based cross-linking accelerator and the like can be mentioned. The cross-linking accelerator may be used alone or in combination of two or more.

Examples of the thiuram-based cross-linking accelerator include tetramethylthium disulfide, tetraethyl thiuram disulfide, tetrabutyl thiuram disulfide, dipentamethylene thiuram tetrasulfide, dipentamethylene thiuram hexasulfide, and tetramethyl thiuram monosulfide.

Examples of the thiazole-based cross-linking accelerator include mercaptobenzothiazole, dibenzothiadyl-disulfide, various metal salts of 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, and 2- (N, N-diethylthiocarbamoylthio). Benzothiazole, 2- (4'-monohorino-dithio) benzothiazole, di-2-benzothiazolyl disulfide and the like can be mentioned.

Examples of the morpholine sulfide-based cross-linking accelerator include morpholine disulfide.

Examples of the sulfenamide-based cross-linking accelerator include N-cyclohexyl-2-benzothiadyl-sulfenamide, N, N-dicyclohexyl-2-benzothiadyl-sulfenamide, N-oxydiethylene-2-benzothiadyl-sulfenamide, and N. -The third butyl-2-benzothiadyl-sulfenamide, N-third butyl-di (2-benzothiazole) sulfenamide and the like can be mentioned.

Examples of the guanidine-based cross-linking accelerator include diphenylguanidine and ditrilguanidine.

Examples of the thiourea-based cross-linking accelerator include ethylene thiourea, diethylene thiourea, dibutyl thiourea, dilauryl thiourea, trimethyl thiourea, and diphenyl thiourea.

Examples of the aldehyde-ammonia-based cross-linking accelerator include hexamethylenetetramine.

Examples of the dithiocarbamate-based cross-linking accelerator include zinc dimethyldithiocarbamate, zinc diethylcarbamate, zinc N-pentamethylenedithiocarbamate and the like.

Examples of the xanthogenate-based cross-linking accelerator include zinc isopropylxanthogenate and zinc butylxanthogenate.

Examples of the fatty acid alkali metal salt-based cross-linking accelerator include sodium stearate and potassium stearate.

Examples of the DBU salt-based cross-linking accelerator include DBU-carbonate, DBU-stearate, DBU-2-ethylhexylate, DBU-benzoate, DBU-salicylate, and DBU-3-hydroxy-2-naphthoate. , DBU-phenol resin salt, DBU-2-mercaptobenzothiazole salt, DBU-2-mercaptobenzimidazole salt and the like.

Examples of the DBN salt-based cross-linking accelerator include DBN-carbonate, DBN-stearate, DBN-2-ethylhexylate, DBN-benzoate, DBN-salicylate, and DBN-3-hydroxy-2-naphthoate. , DBN-phenol resin salt, DBN-2-mercaptobenzothiazole salt, DBN-2-mercaptobenzimidazole salt and the like.

The blending amount of the cross-linking accelerator shall be 0.1 to 15 parts by weight when the total of (a) the polyether polymer and (b) the polymethyl methacrylate resin of the present invention is 100 parts by weight. Is preferable, 0.1 to 10 parts by weight is more preferable, and 0.1 to 5 parts by weight is particularly preferable.

For the rubber composition of the present invention, various acid receiving agents, fillers, plasticizers, processing aids, flame retardants, pigments, which are used in the art in addition to the above, as long as the effects of the present invention are not impaired. , Anti-aging agent, conductive agent and the like can be optionally blended. These may be used alone or in combination of two or more.

As the acid receiving agent used in the present invention, known acid receiving agents can be used, but metal compounds and / or inorganic microporous crystals are preferable. Examples of the metal compound include oxides of Group II (Groups 2 and 12) metals in the periodic table, hydroxides, carbonates, carboxylates, silicates, borates, phosphites, and Group III of the periodic table. (Groups 3 and 13) Metal oxides, hydroxides, carboxylates, silicates, sulfates, nitrates, phosphates, periodic table Group IV (Groups 4 and 14) metal oxides, Examples thereof include metal compounds such as basic carbonates, basic carboxylates, basic subphosphates, basic sulfites, and tribasic sulfates.

Specific examples of the metal compound include magnesia, magnesium hydroxide, aluminum hydroxide, barium hydroxide, sodium carbonate, magnesium carbonate, barium carbonate, fresh lime, slaked lime, calcium carbonate, calcium silicate, calcium stearate, zinc stearate, and the like. Calcium phthalate, calcium phosphite, zinc flower, tin oxide, litharge, lead tan, lead white, dibasic lead phthalate, dibasic lead carbonate, tin stearate, basic lead phosphite, basic phosphite Examples thereof include tin, basic lead sulfite, and tribasic lead sulfate, and sodium carbonate, magnesia, magnesium hydroxide, fresh lime, slaked lime, calcium silicate, zinc flower, and the like are preferable.

The inorganic microporous crystal means a crystalline porous body, and can be clearly distinguished from an atypical porous body such as silica gel and alumina. Examples of such inorganic microporous crystals include zeolites, aluminophosphate-type molecular sieves, layered silicates, synthetic hydrotalcites, alkali metal titanates and the like. Particularly preferred acid receiving agents include synthetic hydrotalcite.

The zeolites are, in addition to natural zeolites, various zeolites such as A-type, X-type, and Y-type synthetic zeolites, sodalites, natural or synthetic mordenites, and ZSM-5, and metal substituents thereof. It may be used in combination of two or more kinds. The metal of the metal substituent is often sodium. As the zeolites, those having a large acid receptivity are preferable, and type A zeolites are preferable.

The synthetic hydrotalcite is represented by the following general formula (1).
Mg _X Zn _Y Al _Z (OH) _{(2 (X + Y) + 3Z-2)} CO ₃・ wH ₂ O (1)
[In the equation, X and Y are real numbers of 0 to 10 having a relationship of X + Y = 1 to 10, Z is a real number of 1 to 5, and w is a real number of 0 to 10, respectively. ]

As an example of the hydrotalcites represented by the general formula (1), Mg _4.5 Al ₂ (OH) ₁₃ CO 3.3.5H ₂ O, Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ _, Mg ₄ Al ₂ (OH) ₁₂ CO ₃・ 3.5H ₂ O, Mg ₆ Al ₂ (OH) ₁₆ CO ₃・ 4H ₂ O, Mg ₅ Al ₂ (OH) ₁₄ CO ₃・ 4H ₂ O, Mg ₃ Al ₂ (OH) ₁₀ CO 3.1.7H ₂ O, Mg ₃ ZnAl ₂ (OH) ₁₂ CO _3.3.5H ₂ O, Mg ₃ ZnAl ₂ ₍ OH) ₁₂ CO ₃ and the like can be mentioned.

The blending amount of the acid receiving agent shall be 0.1 to 15 parts by mass when the total of (a) the polyether polymer of the present invention and (b) the polymethyl methacrylate resin is 100 parts by mass. It is preferably 0.5 to 10 parts by mass, and particularly preferably 1 to 5 parts by mass.

Specific examples of anti-aging agents include benzimidazole-based anti-aging agents, dithiocarbamate-based anti-aging agents, amine-based anti-aging agents, phenol-based anti-aging agents, thiourea-based anti-aging agents, organic thioic acids, and subphosphorus. Acids are mentioned, and at least one selected from these is preferable, benzimidazole-based anti-aging agents and dithiocarbamate-based anti-aging agents are more preferable, and dithiocarbamate-based anti-aging agents are more preferable.

Examples of the benzimidazole-based antiaging agent include zinc salts of 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, and 2-mercaptobenzimidazole.

Specific examples of the dithiocarbamate-based antiaging agent are nickel diethyldithiocarbamate, nickel dimethyldithiocarbamate, nickel dibutyldithiocarbamate, nickel diisobutyldithiocarbamate, copper dimethyldithiocarbamate, copper diethyldithiocarbamate, copper dibutyldithiocarbamate, N. Examples thereof include copper ethyl-N-phenyldithiocarbamate, copper N-pentamethylene dithiocarbamate, and copper dibenzyldithiocarbamate.

Examples of the amine-based antiaging agent include phenyl-α-naphthylamine, phenyl-β-naphthylamine, p- (p-toluenesulfonylamide) -diphenylamine, 4,4'-(α, α'-dimethylbenzyl) diphenylamine, 4 , 4'-Dioctyl diphenylamine, high temperature reaction product of diphenylamine and acetone, low temperature reaction product of diphenylamine and acetone and low temperature reaction product, low temperature reaction product of diphenylamine, aniline, acetone, reaction product of diphenylamine and diisobutylene, octylated diphenylamine, Dioctylated diphenylamine, p, p'-dioctyl-diphenylamine, octylated diphenylamine mixture, substituted diphenylamine, alkylated diphenylamine, alkylated diphenylamine mixture, aralkylated diphenylamine-based alkyl and aralkyl-substituted phenol mixture, diphenylamine derivative, N, N'-diphenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N, N'-di-2-naphthyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl -P-Phenylenideamine, N-Phenyl-N'-(3-methacryloyloxy-2-hydroxypropyl) -p-Phenylenideamine, N, N'-bis (1-methylheptyl) -p-Phenylenideamine, N, N'-bis (1,4-dimethylpentyl) -p-phenylenediamine, N, N'-bis (1-ethyl-3-methylpentyl) -p-phenylenediamine, N- (1,3-dimethylbutyl) There are a mixture of -N'-phenyl-p-phenylenediamine, diallyl-p-phenylenediamine, phenyl, hexyl-p-phenylenediamine, phenyl, octyl-p-phenylenediamine, etc., and aromatic amines as other amines. Condensed product of and aliphatic ketone, butylaldehyde-aniline condensate, polymer of 2,2,4-trimethyl-1,2-dihydroquinoline, 6-ethoxy-2,2,4-trimethyl-1,2-dihydro Examples thereof include quinoline, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, 4,4'-bis (a, a-dimethylbenzyl) diphenylamine, N, N'-di-2-naphthyl-. It is preferably at least one selected from p-phenylenediamine.

Examples of the phenolic antiaging agent include 2,5-di- (t-amyl) -hydroquinone, 2,5-di-t-butylhydroquinone, and hydroquinone monomethyl ether, and the monophenolic agent is 1-oxy-3-. Methyl-4-isopropylbenzene, 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-ethylphenol, 2,6-di-t-butyl-4-methylphenol, 2,6 -Di-t-butyl-4-sec-butylphenol, butyl hydroxyanisole, 2- (1-methylcyclohexyl) -4,6-dimethylphenol, 2,6-di-t-butyl-α-dimethylamino-p -Cresol, alkylated phenol, aralkyl substituted phenol, phenol derivative, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-cyclohexylphenol), 2 , 2'-methylenebis (4-ethyl-6-tert-butylphenol), 4,4'-methylenebis (2,6-di-tert-butylphenol), 2,2-methylenebis (6-α-methyl-benzyl-p) -Cresol), 4,4'-butylidenebis (3-methyl-6-tert-butyl cresol), 2,2'-etylidenebis (4,6-di-tert-butylphenol), 1,1'-bis (4) -Hydroxyphenyl) -cyclohexane, 2,2'-dihydroxy-3,3'-di- (α-methylcyclohexyl) -5,5-dimethyldiphenylmethane, alkylated bisphenol, butylation of p-cresol and dicyclopentadiene Reaction product, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 1,3,5-tris (4-tert-butyl) -3-Hydroxy-2,6-dimethylbenzyl) isocyanurate, 2-tert-butyl-6- (3'-tert-butyl-5'-methyl-2'-hydroxybenzyl) -4-methylphenyl acrylate, 2- [1- (2-Hydroxy-3,5-di-tert-pentylphenyl) -ethyl] -4,6-di-tert-pentylphenyl acrylate, 3,9-bis [2- {3 (3- (3-) tert-Butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] un Decane, butylic acid 3,3-bis (3-tert-butyl-4-hydroxyphenyl) ethylene ester, 1,3,5-tri (2-hydroxyethyl) -s-triazine-2,4,6- (1H) , 3H, 5H) Trione 3,5-di-tert-butyl-4-hydroxyhydrolauric acid triester, modified polyalkyl subphosphate polyvalent phenol, 4,4'-thiobis (6-tert-butyl-) 3-Methylphenol), 4,4'-thiobis (3-methyl-6-tert-butylphenol), 4,4'-thiobis- (6-tert-butyl-o-cresol), 4,4'-di and Tri-thiobis- (6-tert-butyl-o-cresol), bis (3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, 1,1,3-tris- (2-methyl-4-) Hydroxy-5-tert-butylphenyl) butane, 4,4'-butylidenebis (3-methyl-6-tert-butylphenol), 2,2-thiobis (4-methyl-6-tert-butylphenol), n-octadecyl- 3- (4'-Hydroxy-3', 5'-di-tert-butyl-phenyl) propionate, tetrakis- [methylene-3- (3', 5'-di-tert-butyl-4'-hydroxyphenyl) Propionate] methane, pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4) -Hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis (n-octylthio) -6- (4-Hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, Tris- (3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanurate, 2,2- Thio-diethylenebis [3- (3,5-tert-butyl-4-hydroxyphenyl) propionate], N, N'-hexamethirebis (3,5-tert-butyl-4-hydroxy-hydrocinnamamide), 2 , 4-Bis [(octylthio) methyl] -o-cresol, 3,5-di-tert-butyl-4-hydroxybenzyl-phosphonate-diethyl ester, tetrakis [methylene (3,5-di-t) ert-butyl-4-hydroxyhydrocinnamate)] methane, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid ester, hindered phenol, hindered bisphenol, 2-hydroxynaphthalene -3-Carboil-2'-methoxyanilide, 2-hydroxynaphthalene-3-carboyl-2'-methylanilide, 2-hydroxynaphthalen-3-carboyl-4'-methoxyanilide, 4,4'-bis (N, Examples thereof include N'-dimethylamino) -triphenylmethane, 2-hydroxynaphthalene-3-carboylanilide, 1,1'-bis (4,4'-N, N'-dimethylaminophenyl) -cyclohexane, and the like. 2,2'-Methylenebis (4-ethyl-6-tert-butylphenol), 2'2-Methylenebis (4-methyl-6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert- Butylphenol), preferably at least one selected from 4,4'-thiobis (3-methyl-6-tert-butylphenol).

Examples of the thiourea-based antiaging agent include 1,3-bis (dimethyl-aminopropyl) -2-thiourea and tributylthiourea. It was

Dilauryl thiodipropionate, disstearyl thiodipropionate, dimyristyl-3,3'-thiodipropionate, ditridecyl-3,3'-thiodipropionate, pentaerythritol-tetrakis- (β) as organic thioacids -Lauryl-thiopropionate), dilauryl-thiodipropionate and the like are exemplified.

Examples of phosphites include tris (nonyl-phenyl) phosphite, tris (mixed mono- and di-nonylphenyl) phosphite, diphenyl mono (2-ethylhexyl) phosphite, diphenyl monotridecyl phosphite, and diphenyl isodecyl. -Phosfite, Diphenyl-Isooctyl-Phosfite, Diphenyl-Nonylphenyl-Phosphite, Triphenylphosphite, Tris (Tridecyl) Phosfite, Triisodecylphosfite, Tris (2-ethylhexyl) Phosfite, Tris (2, 4-Di-tert-butylphenyl) phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite, 1,1,3-tris (2-methyl-4-di-) Tridecylphosfite-5-tert-butylphenyl) butane, 4,4'-butylidenebis (3-methyl-6-tert-butyl-di-tridecylphosfite), 2,2'-ethylidenebis (4,6) -Di-tert-butylphenol) fluorophosphite, 4,4'- _isopropidene -diphenolalkyl ₍ C12-C15) phosphite, cyclic neopentanetetraylbis (2,4-di-tert-butylphenylphoss) Fight), Cyclic Neopentantetraylbis (2,6-di-tert-butyl-4-phenylphosphite), Cyclic Neopentantetraylbis (Nonylphenylphosphite), Bis (Nonylphenyl) Pentaerythritol diphosphite , Dibutylhydrogenphosphite, distearyl / pentaerythritol / diphosfite, hydrogenated bisphenol A / pentaerythritol phosphite / polymer and the like are exemplified.

The lower limit of the amount of the antiaging agent added is 0.01 part by mass or more when the total of (a) the polyether polymer and (b) the polymethylmethacrylate resin of the present invention is 100 parts by mass. It is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and the upper limit is preferably 3.5 parts by mass or less, and 3.0 parts by mass. The following is particularly preferable.

As the reinforcing agent, a known reinforcing agent can be used, specifically, calcium carbonate, talc, silica, clay, carbon fiber, glass fiber, carbon black, titanium oxide, magnesium oxide, hydrotalcite, and hydroxylation. Examples thereof include magnesium, antimony oxide, zinc oxide and the like, and carbon black and silica are preferable.

Examples of carbon black include furnace black, acetylene black, thermal black, channel black, graphite and the like, and specifically, SAF, ISAF, HAF, EPC, XCF, FEF, GPF, HMF, SRF, FT and MT. It can be exemplified. These carbon blacks may be used alone or in combination of two or more.

The type of silica is not particularly limited, and is, for example, wet method silica (hydrous silicic acid), dry method silica (anhydrous silicic acid), calcium silicate, aluminum silicate, and the like. As the silica to be used, wet method silica is preferable. Wet method silica is a fine particle of hydrous silicic acid produced by acid decomposition of an aqueous sodium silicate solution or an alkaline earth metal silicate, and is a filler for rubber mainly composed of silicon dioxide.

The blending amount of the reinforcing agent is preferably 10 to 100 parts by mass, preferably 20 parts by mass when the total of (a) the polyether polymer and (b) the polymethyl methacrylate resin of the present invention is 100 parts by mass. It is more preferably to 80 parts by mass.

Specific examples of the processing aid include paraffin waxes such as paraffin waxes and hydrocarbon waxes and hydrocarbon resins; fatty acids such as stearic acid and palmitic acid; fatty acid amides such as stearoamide and oleylamide; n-. Fatty acid esters such as butyl stearate; sorbitan fatty acid esters such as sorbitan stearate; fatty alcohols; etc. may be mentioned, and these may be used alone or in combination of two or more.

The blending amount of the processing aid shall be 0.1 to 20 parts by mass when the total of (a) the polyether polymer of the present invention and (b) the polymethyl methacrylate resin is 100 parts by mass. Is preferable, and 0.3 to 10 parts by mass is more preferable.

Examples of the plasticizer include phthalic acid derivatives such as dioctyl phthalate (bis phthalate (2-ethylhexyl)) and diallyl ester phthalate, adipic acid derivatives such as dibutyl diglycol-adipate and di (butoxyethoxy) ethyl adipate, and sebacic acid. Examples thereof include sebacic acid derivatives such as dioctyl and trimellitic acid derivatives such as trioctyl remeritate, and these may be used alone or in combination of two or more.

The blending amount of the plasticizer may be 0.1 to 50 parts by mass when the total of (a) the polyether polymer and (b) the polymethyl methacrylate resin of the present invention is 100 parts by mass. It is preferably 3 to 35 parts by mass, and more preferably 3 to 35 parts by mass.

Method for Producing Rubber Composition As the method for producing the rubber composition of the present invention, any means conventionally used in the field of polymer processing, for example, a mixing roll, a Banbury mixer, various kneaders and the like can be used.

In the rubber composition of the present invention, since it is not possible to sufficiently knead the composition using a normal polyether polymer at the kneading temperature, it is preferable to knead at a high temperature such as 180 ° C. to 250 ° C. It is also possible to knead (a) a polyether polymer and (b) a polymethyl methacrylate resin at a high temperature of 180 ° C to 250 ° C in advance, and then add a cross-linking agent or the like to knead. be. The high temperature is preferably a temperature about 60 ° C. to 150 ° C. higher than the Vicat softening temperature of the polymethyl methacrylate resin used.

Crosslinked product The crosslinked product of the present invention is produced from the rubber composition of the present invention and obtained by cross-linking. It is usually obtained by heating to 100 to 200 ° C., and the crosslinking time varies depending on the temperature, but it is usually carried out between 0.5 and 300 minutes. As the method of cross-linking molding, any method such as compression molding by a mold, injection molding, air bath, heating by infrared rays or microwaves can be used.

The crosslinked product of the present invention is a crosslinked product prepared from a rubber composition containing (a) a polyether polymer, (b) a polymethyl methacrylate resin, and (c) a cross-linking agent.
When the mass of the rubber composition is A and the mass of (b) polymethylmethacrylate resin in the rubber composition is B, B / A and the crosslinked product (mass X) are used as a solvent for soxley extraction at 78 ° C. 6 It is a crosslinked product in which Y / X satisfies the following formula (1) when the extraction amount (mass Y) after the time is changed.
0.10 ≤ (Y / X) / (B / A) ≤ 0.90 (1)

In the formula (1), the lower limit of (Y / X) / (B / A) is 0.10 or more, may be 0.15 or more, may be 0.20 or more, and may be 0.25 or more. It may be 0.30 or more, 0.35 or more, and the upper limit is 0.90 or less, preferably 0.80 or less, and preferably 0.75 or less. More preferably, it is more preferably 0.70 or less, particularly preferably 0.65 or less, most preferably 0.60 or less, even more preferably 0.55 or less, and 0. More preferably, it is 50 or less.

The B / A is preferably 0.10 or more, more preferably 0.12 or more, still more preferably 0.15 or more, preferably 0.70 or less, more preferably 0.60 or less, still more preferably 0. It is 50 or less, particularly preferably 0.40 or less.

Soxhlet extraction is performed according to JIS-K6229. Specifically, the crosslinked product is cut into 1 cm pieces, weighed 5 g, placed in a cylindrical filter paper, and set in a cylinder. Further, 100 ml of acetone is placed in an Erlenmeyer flask and set at the bottom. The heater is set to 78 ° C., the cooling is set to 20 ° C., and Soxhlet extraction is performed for 6 hours. Take out the cylindrical filter paper, volatilize acetone, measure the mass, and use the reduced amount of the sample as the extraction amount.

A crosslinked product satisfying the above formula (1) can be produced, for example, as follows.
The mass ratio of (a) the polyether polymer and (b) the polymethyl methacrylate resin in the rubber composition of the present invention may be adjusted to the above-mentioned preferable range. Further, as described above, in the rubber composition of the present invention, it is preferable to knead at a high temperature such as 180 ° C. to 250 ° C., and in advance, at a high temperature such as 180 ° C. to 250 ° C., (a) a polyether system. It is also preferable to knead the polymer and (b) the polymethyl methacrylate resin, and then add a cross-linking agent or the like to knead the mixture.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples as long as it does not deviate from the gist thereof.

First, each compounding agent shown in Table 1 was kneaded with a pressure kneader to prepare an A kneading compound. This A kneading compound was kneaded with an open roll to prepare a B kneading compound. In the table, A is a raw material of the A kneading compound, and B is a raw material to be blended in the A kneading compound when the B kneading compound is produced. The unit in the formulation is parts by mass.

Specifically, in Comparative Example 2, Example 1, and Example 2, the polyether polymer and the polymethyl methacrylate resin were pre-kneaded at a pressure kneader at 190 ° C., and the polyether polymer and the polymethyl methacrylate resin were pre-kneaded. After preparing the masterbatch with and, other raw materials for the A kneading compound were added and further kneaded at 150 ° C. to prepare the A kneading compound. To the obtained A kneaded sheet, 1.7 parts by mass of quinomethionate was added to a total of 100 parts by mass of the polyether polymer and the polymethyl methacrylate resin, and the sheet was formed by an open roll.
In Comparative Example 1, the compounding agents shown in Table 1 were kneaded at 150 ° C. with a pressure kneader to prepare an A kneading compound, which was molded into a sheet using an open roll to obtain an A kneading sheet. To 100 parts by mass of the polyether polymer, 1.7 parts by mass of quinomethionate was added to the obtained A kneaded sheet, and the sheet was formed into a sheet by an open roll.
In Example 3, the compounding agents shown in Table 1 were kneaded at 190 ° C. with a pressure kneader to prepare an A kneading compound, which was molded into a sheet using an open roll to obtain an A kneading sheet. To the obtained A kneaded sheet, 1.7 parts by mass of quinomethionate was added to a total of 100 parts by mass of the polyether polymer and the polymethyl methacrylate resin, and the sheet was formed by an open roll.
In Comparative Example 3, the compounding agents shown in Table 1 were kneaded at 150 ° C. with a pressure kneader to prepare an A kneading compound, which was molded into a sheet using an open roll to obtain an A kneading sheet. To the obtained A kneaded sheet, 1.7 parts by mass of quinomethionate was added to a total of 100 parts by mass of the polyether polymer and the polymethyl methacrylate resin, and the sheet was formed by an open roll.
The sheets obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were press-crosslinked at 170 ° C. for 15 minutes to obtain crosslinked sheets.

Using the obtained crosslinked sheet, a tensile test was carried out according to JIS K6251 and a hardness test was carried out according to JIS K6253. Heat resistance test according to JIS K6257 accelerated aging test A-2 method, tensile test according to JIS K6251 after heat resistance test (150 ° C x 168 hours, 150 ° C x 288 hours), hardness according to K6253 The test was carried out. An oil resistance test was carried out according to JIS K6258, a tensile test was carried out according to JIS K6251 after an engine oil resistance test (grade: 5W-40, 150 ° C. x 70 hours), and a hardness test was carried out according to K6253. ..

Soxhlet extraction Soxhlet extraction is performed according to JIS-K6229. Specifically, the crosslinked sheet is cut into 1 cm pieces, weighed in 5 g (X), placed in a cylindrical filter paper, and set in a cylinder. Further, 100 ml of acetone is placed in an Erlenmeyer flask and set at the bottom. The heater is set to 78 ° C., the cooling is set to 20 ° C., and Soxhlet extraction is performed for 6 hours. Take out the cylindrical filter paper, volatilize acetone, measure the mass, and use the weight loss (Y) of the sample as the extraction amount.

When the mass of the rubber composition is A and the mass of (b) polymethylmethacrylate resin in the rubber composition is B, B / A and the crosslinked product (mass X) are used as a solvent for soxley extraction at 78 ° C. 6 Table 1 shows (Y / X) / (B / A) calculated from Y / X when the extraction amount (mass Y) after the time has passed.

The compounding agents used in the implementation and comparative examples are shown below.
* 1 Epichlorohydrin-ethylene oxide binary copolymer "Epichromer C" manufactured by Osaka Soda Co., Ltd. (Constituent unit based on epichlorohydrin: 50 mol%, Constituent unit based on ethylene oxide: 50 mol%)
* 2 "Acripet VH001" manufactured by Mitsubishi Rayon Co., Ltd. (Vicut softening temperature 107 ° C)
* 3 "Seast SO" manufactured by Tokai Carbon Co., Ltd.
* 4 "ADEKA SIZER RS-107" manufactured by ADEKA CORPORATION
* 5 "Splendor R-300V" manufactured by Kao Corporation
* 6 "Nocrack NBC" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.
* 7 "STABIACE HT-1" manufactured by Sakai Chemical Industry Co., Ltd.
* 8 "NS Soap" manufactured by Kao Corporation
* 9 "Disonet XL-21S" manufactured by Osaka Soda Co., Ltd.

Table 2 shows the test results obtained from each test method. In the table, Tb means the tensile strength specified in the tensile test, Eb means the elongation specified in the tensile test, and Hs means the hardness.

In Table 2, the crosslinked products of Examples 1 to 3 are superior in TB values after the heat aging test and the engine oil resistance test as compared with the crosslinked products of Comparative Examples 1 to 3, and have excellent heat resistance and oil resistance. It was shown that (engine oil resistance) was excellent. The heat resistance test (150 ° C. × 288 hours) of Comparative Example 1 could not be measured due to softening deterioration.

The crosslinked product obtained by cross-linking the rubber composition of the present invention has excellent heat resistance and oil resistance, and is therefore useful as a tube material for fuel hoses, air hoses, etc., and rubber packing, especially in automobile applications.

Claims

A crosslinked product prepared from a rubber composition containing (a) a polyether polymer, (b) a polymethyl methacrylate resin, and (c) a crosslinking agent.
When the mass of the rubber composition is A and the mass of (b) polymethylmethacrylate resin in the rubber composition is B, B / A and the crosslinked product (mass X) are used as a solvent for soxley extraction at 78 ° C. 6 A crosslinked product in which Y / X satisfies the following formula (1) when the extraction amount (mass Y) after the time is changed.
0.10 ≤ (Y / X) / (B / A) ≤ 0.90 (1)
The crosslinked product according to claim 1, wherein the (a) polyether-based polymer contains at least one unit selected from ethylene oxide, propylene oxide, epichlorohydrin, and allyl glycidyl ether as a constituent unit. It was