WO1993013185A1 - Lubricating oil for refrigerator - Google Patents

Abstract

A lubricating oil for a refrigerator using a chlorofluorocarbon substitute as the refrigerant, which contains a polymer of a fumaric ester or a copolymer of a fumaric ester with a copolymerizable alkylene and, if desired, an organic carboxylic ester or a polyalkylene glycol with a kinematic viscosity of 2 to 30 cSt. The oil is compatible with a refrigerant comprising a chloroflurocarbon substitute such as a hydrochlorofluorocarbon, in particular, R134a in a wide temperature range, has a high viscosity index, is thermally and chemically stable, and has an excellent lubricity.

Description

 Specification

 Lubricating oil for refrigerator

 Technical field

 The present invention relates to a lubricating oil for a refrigerator using an alternative Freon refrigerant, and more particularly, to a lubricating oil for a refrigerator using a hydrogenated halogenated hydrocarbon refrigerant. The present invention also relates to a fumarate copolymer suitable as the lubricating oil.

 Background art

Conventionally, air cooler buildings, refrigerators, as the refrigerant used in the refrigerating machine such as an air _{conditioner, R11 (CC 1 3 F)} , but fluorocarbon refrigerant such as R12 (CC 1 ₂ F ₂₎ has been used, hydrocarbons These chlorofluorocarbons, in which all of the hydrogen is replaced by halogens containing chlorine, are globally regulated because they lead to destruction of the stratospheric ozone layer. Therefore, for example, as a risk-free alternative flon refrigerants destroy the ozone _{layer, R22 (CHC 1 F 2)} , R 123 (CF 3 CHC 12), R141b N <CC 1 2 FCH 3), R134a (CF ¾ CH 2 Hydrogenated halogenated hydrocarbon refrigerants such as F) and R152a (CHF ₉ CH 3) have been developed. Among others, non-chlorinated halogenated carbonitride hydrogen, for example _{R 134a {CF 3 CH 2 F} ), R152a (CH F 2 CH3), R125 (CHF 2 CF 3), R32 (CH 2 F 2) , etc. and their Promising mixed refrigerants.

Lubricating oils for refrigerators generally have a wide range of compatibility temperature with the refrigerant (compatibility), that is, they do not show up at high temperatures (the solvation of the refrigerant with the lubricating oil is large), and the molecular polarity of the lubricating oil Is large, and there is no precipitation of lubricating oil at low temperatures (the solubility of the lubricating oil in the refrigerant is high). In addition, various chillers have different kinematic viscosity ranges. _Φ required to have kinematic viscosity corresponding to For conventional fluorocarbon refrigerants, naphthenic mineral oil, paraffinic mineral oil, alkylbenzene, polyglycol mineral oil, ester oil, etc. were used as lubricating oils. There is little compatibility and they cannot be used. Therefore, polyalkylene glycol-based and polyol polyester-based lubricants have been developed. For example, Ulcon LB-165 and Ulcon LB-525 (both are trademarks, Union Carbide Co., Ltd.) comprising polyalkylene glycols are known as having compatibility with Freon 134a. A composition for a high viscosity refrigerator based on polyoxypropylene glycol monobutyl ether is also known (Japanese Patent Publication No. 57-42119). Polyoxyalkylene glycols having at least two hydroxyl groups in the molecule have been proposed (U.S.P. 4,755,316). A glycidyl methyl ether-propylene oxide copolymer or a glycidyl methyl ether polymer having terminal groups of methoxy group and hydroxyl group is known as a lubricating oil for refrigerators (JP-A-3-205492).

 However, in all cases, high kinematic viscosity products have low compatibility with the alternative chlorofluorocarbons, and polyalkylene glycol-based lubricating oils have high hygroscopicity, and thus have problems such as generation.

Disclosure of the invention

 Accordingly, it is an object of the present invention to provide a lubricating oil suitable for a refrigerator using a hydrogen-containing halogenated hydrocarbon refrigerant alternative to a halogenated hydrocarbon refrigerant, particularly a non-chlorinated halogenated hydrocarbon refrigerant. .

The present invention provides a lubricating oil for a refrigerator comprising a bumaric acid ester polymer mainly comprising a repeating unit represented by the following general formula (I) and, if desired, a line repeating unit represented by the following general formula (Π). It is a lubricating oil for refrigerators characterized by containing. C OOR 1

 -CH- -CH——

 COOR 1

 -R 2 (ID wherein each may be the same or different from each other and may be straight-chain or branched

To c ₉ alkyl group, Ariru group, and selected from the group consisting of capped or unsubstituted polyamide Rukirenokisai de residue; each R ₂ may mutually identical or different, from the group consisting of alkylene and substituted alkylene group At least two repeating units (I) and at least the same number as the repeating units (II) in the polymer; and the units (II) need not be present. The units (I) and (II) can form a random copolymer or a block copolymer.

BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a chart showing the results of 1H-NMR analysis of the fumarate ester copolymer of the present invention produced in Example 18.

 FIG. 2 shows the fumarate ester copolymer of the present invention produced in Example 18.

 I

 13

 9 is a chart showing the results of analysis by C-NHR.

 FIG. 3 shows the results of the production of the fumaric acid ester copolymer of the present invention produced in Example 19.

4 is a chart showing the results of analysis by 1 H-NMR.

 FIG. 4 shows the fumaric acid ester copolymer of the present invention produced in Example 19.

¹³ is a chart showing the results of ¹³ C analysis.

Figure 5 is a chart showing the results of analysis according to ¹ H-NMR of fumarate Jechiru polymer prepared in Comparative Example 1 0 _¾

FIG. 6 is a chart showing the results of ¹³ C-HMR analysis of the getyl fumarate polymer produced in Comparative Example 10.

FIG. 7 shows the ¹ H-NMR of the getyl fumarate polymer produced in Comparative Example 11. 6 is a chart showing the results of the analysis.

FIG. 8 is a chart showing the results of ¹³ C-NMR analysis of the getyl fumarate polymer produced in Comparative Example 11.

 BEST MODE FOR CARRYING OUT THE INVENTION

 The above fumaric acid ester polymer is a fumaric acid ester or a polymerization product of a fumaric acid ester and a copolymerizable alkylene, and both ends thereof are residues of a polymerization initiator used in the polymerization.

—In the general formula (I), 1 ^ is linear or branched. To c ₉ alkyl Le group (including Aruaruki group), preferably a C _j to c ₆ alkyl group; Ariru group (including alkaryl), preferably or phenyl group cresyl group; terminal substituted or unsubstituted A polyalkylene oxide residue, preferably a compound of the formula-(AO) ,,-X wherein A is an ethylene, propylene or butylene group, X is a hydrogen atom or a Cj- ₄ alkyl group, and X is Which is an integer of 1 to 4], especially those having 4 to 6 carbon atoms excluding the number of carbon atoms of the terminal group X (the more carbon atoms, the lower the compatibility with cold). For example, a diethylene glycol monoethyl ether residue and an ethylene glycol monoethyl ether residue are preferable.

 R-! Is a butyl group, or a butyl group and an ethyl group (ratio of 8: 2 or more), and a polymer containing 8 or more repeating units (I) is particularly preferable in terms of viscosity, viscosity index and phase with the refrigerant. Excellent balance of solubility

—In the general formula (II), H ₂ is a substituted or unsubstituted alkylene group (including an alkyl group), preferably a c _{2 to} c ₁₂ linear, branched or cycloalkylene group or oxoalkylene group. These are particularly substituted with ethylene, propylene, butene and styrene.橾 Return unit

By introducing (II) into the polymer, the viscosity index can be further improved. However, the repeating unit (II) is more present in the polymer than the repeating unit (I). Must not be. That is, the proportion of the repeating unit (II) in the copolymer is at most 50 mol%, preferably at most 30 mol%. If this exceeds 50 mol%, the compatibility of the copolymer with the refrigerant will be poor.

The degree of polymerization of the fumaric acid ester polymer is determined so as to have an appropriate kinematic viscosity as a lubricating oil for a refrigerator described below. Kinematic viscosity is preferably in the range of ^{2~100c S t (100 e C)} . The molecular weight (number average) is preferably from 400 to 3000, more preferably from 400 to 1600. As the molecular weight increases, the viscosity index increases, but tends to be solid at room temperature, and the compatibility with the refrigerant tends to decrease. One type of fumaric acid ester copolymer may be used, and two or more types of copolymers having different structures, molecular weights and the like may be used. For example, it is preferable to add a small amount of a fumaric acid ester copolymer having a molecular weight of 400 to 3,000 and a molecular weight of 3000 to 10,000 to improve kinematic viscosity and viscosity index.

 The fumaric acid ester polymer is obtained by polymerizing the monomer corresponding to the repeating unit (I) and, if desired, the repeating unit (（) by heating under reflux in the presence of a polymerization initiator. When starting from the corresponding maleic acid alkyl ester, an isomerization catalyst is additionally used. When an isomerization catalyst is added, it is thought that the maleate ester is firstly isomerized to a fumarate ester, and this polymerizes (Acta Polymerica 39 (1988) No. 1, 5-8. The polymerization can be carried out in the same manner as in the case of the above-mentioned polymerization of fumaric acid ester, except that it is added to the polymerization reaction system in a molar ratio of 1 to 27 to 1700 with respect to the starting ester. Morpholine, piperidine, dipyramine, propylamine, and preferably morpholine can be used.

Known polymerization initiators can be used for the polymerization reaction. Azonitrile compounds such as 2,2'-azobisisobutyronitrile, 1- 1'-azobiscyclohexanecarbonitrile, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), etc .; azoamidine compounds For example, 2,2'-azobis (2-methylphenylpropionamidine, 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis [2- (2-imidazoline- 2-yl) propane] dihydrochloride, etc .; azoamide compounds such as 2,2'-azobis (isobutylamide) dihydrochloride, 2,2'-azobis {2-methyl [1,1-bis (hydroxymethyl) ) -2-hydroxyethyl] propionamide}; alkylazo compounds such as azodi-tert-octane, azodi-tert-butane, dimethyl 2,2′-azobisisobutyrate and the like. Organic peroxides are also good Often used, ketone peroxides, such as methylethyl ketone peroxide, cyclohexanone peroxide, methylcyclohexanone peroxide, and the like; peroxyketals, such as 1,1-bis (t-butylperoxy) 3 1,3,5-trimethylcyclohexane, 1,1-bis (t-butyloxy) cyclohexane, 2,2-bis (t-butylperoxy) butane, etc .; hydroperoxide, for example t-butyl high Dropperoxide, di-isopropylpropyl benzene high dropperoxide, etc .; dialkyl peroxide, for example, di-t-butylperoxide, di-cumylperoxide, t-butylcumylperoxide, etc .; A silver oxide, for example, acetyl peroxide, isoptyryl peroxide Peroxydicarbonates, such as di-isopropyl peroxydicarbonate, di-n-propyl dicarbonate, di-methoxypropyl propyl peroxydicarbonate; peroxyesters, such as t -Butyl peroxy acetate, t-butyl peroxy isobutyrate, cumyl peroxy neodecaneate, t-butyl peroxybe Zozoate, t-hexyloxyneodecanoate and the like, but are not limited thereto. Preferred initiators are 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), t-butyl peroxide and di-t-butyl peroxyside. t-Butyl peroxide! Preferred for!

 The polymerization initiator is preferably used in a molar ratio of at least 1Z100, particularly at least 3Z100, based on the raw materials. Even if the total amount is too large, there is no particularly advantageous effect, and generally the molar ratio is 2 to 10 or less.

 In order to improve the yield, it is preferable to add the initiator to the polymerization reaction system batchwise or continuously instead of adding it all at once. The polymerization temperature is preferably from 50 to 180, especially from 80 to 160. It is preferred that after all of the initiator is added, reflux stirring is continued while maintaining this temperature. It takes 6 to 72 hours, preferably 10 to 30 hours, from the start of the addition of the initiator to the termination of the polymerization reaction.

The polymerization reaction system may further include a solvent. The amount of the solvent is preferably such that the starting ester concentration is 10% by weight or more. As the solvent, those commonly used in radical Polymerization, for example, cyclohexanone methyl E chill ketone, methyl isobutyl Ke Bokun, cyclohexane, p - xylene, 0 - xylene, benzene, toluene, tetrahydrofuran and the like _Φ

 Particularly preferred embodiment (Α)

 Particularly preferred lubricating oils for refrigerators according to the invention have the formula (III)

COOC ₂ H ₅

 —— CH—— CH—— (III)

COOC ₂ H ₅

1 to 50 mol% of the structural unit represented by the following formula (IV) COO

 C H—— C H (IV)

 C O O R

 Wherein each R is independently a linear or branched alkyl group having 3 to 8 carbon atoms. Contains coalescence.

 When the content is 20 mol% or less, other copolymer components, for example, repeating units (II) can be contained. Such other copolymer components include, for example, ethylene, butene, styrene and the like.

 That is, in this preferred polymer, the repeating unit (I) is

R ₁ is made of repeating units from 50 to 99 mol% is緣返to units 1-50 mol% and a linear or branched _1-8 alkyl group is Echiru group,緣返and units (II) is copolycondensation It constitutes 0 to 20 mol% of the whole combined components.

Examples of R in the formula (IV) include a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group and the like, and structural isomers thereof. Preferably R is an n-butyl group. R may be the same or different. If the structural unit represented by the formula () is more than 50 mol%, that is, if the number of units derived from getyl fumarate is larger than the number of units derived from dialkyl fumarate, the viscosity index is extremely lowered. Would. The copolymer can be any copolymer such as a random copolymer or a block copolymer. Such an alkyl fumarate copolymer can be produced, for example, as follows. First, getyl fumarate and an alkyl fumarate are used as raw materials, and getyl fumarate is 50 mol% or less. Mix in such proportions. Here, it is known that the polymerization of fumarate ester occurs after the isomerization of maleate ester (Acta Polymer ica). 39 (1988) No. 1, 5-8), the corresponding getyl maleate and alkyl maleate can also be used as raw materials. Hereinafter, polymerization can be carried out in the same manner as described above.

 Along with the fumaric acid ester copolymer of this preferred embodiment, fumaric acid esters having other structural units, for example, other fumaric acid esters represented by the above general formulas (I) and (II) can also be used.

 Particularly preferred embodiment (B)

 In another particularly preferred embodiment, the lubricating oil for a refrigerator according to the present invention comprises 5-45 mol% of a structural unit represented by the following formula (V) and 95-55 mol% of a structural unit represented by the following formula (VI). And a fumaric acid ester copolymer having a molecular weight of 800 to 3,000.

COOC ₂ H ₅

 CH • CH (V

C OOC ₂ H _c

C OOC ₄ H ₉

 CH CH (VI)

COOC ₄ Hg

 That is, in this copolymerization, the repeating unit (I) is a repeating unit of 5 to 45 mol% in which II is an ethyl group and a repeating unit 95 to 55 in which II is a linear or branched butyl group. It consists of mol% and does not contain the repeating unit (II).

C ₄ Ho in the formula (VI) includes all structural isomers such as n-butyl, sec-butyl, tert-butyl and isobutyl. The ratio of the structural unit formula (V) is 5 to 45 mol%, preferably 6 to 39 mol%, and the ratio of the structural unit formula (VI) is 95 to 55 mol%, preferably 94 to 61 mol%. It is. The copolymer may be any copolymer such as a random copolymer or a block copolymer. Can be coalesced.

 Such a fumarate ester copolymer can be produced, for example, as follows.First, raw materials such as getyl fumarate and dibutyl fumarate are adjusted so that the respective proportions become the proportions of the respective structural units described above. Merge with. Getyl maleate and dibutyl maleate can also be used as raw materials. Hereinafter, the raw material is polymerized in the presence of a polymerization initiator in the same manner as described above.

 The viscosity index of the fumaric acid ester copolymer is preferably from 100 to 200.

 Along with this preferred embodiment of the fumaric acid ester copolymer, a fumaric acid ester having another structural unit, for example, another fumaric acid ester represented by the above general formulas (I) and (H) or (III) and (IV) Acid esters can also be used.

 Other lubricating oil components

In order to adjust the kinematic viscosity and viscosity index of the lubricating oil for refrigerators of the present invention for various refrigerators, in addition to the above-mentioned fumaric acid ester polymer, for example, an organic carboxylic acid ester, Conventionally used lubricating oil components for refrigerators, such as polyalkylene glycol, alkylbenzene, and mineral oil, which can be used in desired proportions, can be used in a desired ratio. In addition to the fumaric acid ester copolymer, it further contains an organic carboxylic acid ester having a kinematic viscosity at 100 C of 2 to 3 OcSt and Z or polyalkylene glycol. The organic carboxylic acid ester and Z or the polyalkylene glycol are preferably used in an amount of not more than 80 parts by weight based on 20 parts by weight of the fumaric acid ester polymer. If too much, the compatibility of high temperature Or tend to lower the viscosity.

 Examples of such organic carboxylic acid esters include the following having high molecular polarity.

 (1) First, polyol esters of an aliphatic polyhydric alcohol and a linear or branched fatty acid can be used.

 Examples of the aliphatic polyhydric alcohol forming such polyol esters include trimethylolpropane, ditrimethylolpropane, trimethylolethane, ditrimethylolethane, pentaerythritol, dipentaerythritol, and tripentaerythritol. Can be As the fatty acid, those having 3 to 12 carbon atoms are preferable, and preferable examples are propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, and decanoic acid. , Perdecanoic acid, dodecanoic acid, isovaleric acid, neopentanoic acid, 2-methylbutyric acid, 2-ethylbutyric acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, isooctanoic acid, isononanoic acid, isodecanoic acid, 2, 2 '-Dimethyloctanoic acid, 2-butyloctanoic acid and the like.

 Preferred polyesters of the above-mentioned aliphatic polyhydric alcohols and fatty acids are, in particular, pentaerythritol, dipentaerythritol, pentaerythritol and the like or a mixture thereof, with 5 to 12 carbon atoms, more preferably 5 to 5 carbon atoms. 7 fatty acids such as valeric acid, hexanoic acid, heptanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, isooctanoic acid, isononanoic acid, isodecanoic acid, 1,1, dimethyloctanoic acid, 2-butyl Ester oils with octanoic acid or the like or a mixture thereof, which can improve the compatibility with the refrigerant particularly at low temperatures.

Further, partial esters of an aliphatic polyhydric alcohol and a linear or branched fatty acid can also be used. At this time, the above-mentioned polyhydric alcohol can be used as the polyhydric alcohol. Fatty acids include those with 3 to 9 carbon atoms. Preferred and preferred examples include propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, 2-methylhexanoic acid, 2-ethylhexane, isooctanoic acid, isononanoic acid and the like. Is mentioned. These partial esters can be obtained by appropriately adjusting the number of moles of the reaction between the aliphatic polyhydric alcohol and the fatty acid for the reaction.

 (2) Neopentyl glycol is used as an aliphatic polyalcohol, and is used in combination with linear or branched fatty acids having 6 to 9 carbon atoms, such as hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, 2- Diesters with ethyl butyric acid, 2-methylhexanoic acid, 2-ethylhexane acid, isooctanoic acid, isononanoic acid and the like can also be used.

 (3) A partial ester of an aliphatic polyhydric alcohol and a straight-chain or branched fatty acid having 3 to 12 carbon atoms, and a linear or branched aliphatic dibasic acid and a di- or aromatic compound Complex esters with group polybasic acids can also be used.

 Examples of such aliphatic polyalcohols include trimethylolpropane, trimethylolethane, pentaerythritol, and dipentaerythritol.

 Examples of straight-chain or branched fatty acids having 3 to 12 carbon atoms include propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, Dodecanoic acid, 2-methylbutyric acid, 2-ethylbutyric acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, isooctanoic acid, isononanoic acid, isodecanoic acid, 2,2'-dimethyloctanoic acid, 2-butyric acid Cutanoic acid and the like can be used.

In the Complex X steals, when a fatty acid having preferably 5 to 7 carbon atoms, more preferably 5 to 6 carbon atoms is used, the obtained ester oil can improve the compatibility with the refrigerant particularly at low temperatures. As fatty acids, Isovaleric acid, valeric acid, hexanoic acid, 2-methylbutyric acid, 2-ethylbutyric acid or a mixture thereof is used, and those having 5 carbon atoms and 6 carbon atoms are in a weight ratio of 10: 90 to 9 Fatty acids mixed at a ratio of 0:10 can be suitably used.

 Aliphatic dibasic acids that can be used for esterification with polyhydric alcohols together with this fatty acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, pendecanedioic acid, Examples include decandioic acid, tridecandioic acid, carboxiooctadecanoic acid, carboxymethylthioctadecanoic acid, docosantioic acid and the like. Examples of the aromatic dibasic acid include phthalic acid and isophthalic acid, and examples of the aromatic tribasic acid include trimellitic acid, and examples of the aromatic tetrabasic acid include pyromellitic acid. No.

 The ratio of the fatty acid to the aliphatic dibasic acid and / or the aromatic or polybasic acid is preferably 6: 1 (molar ratio). In the esterification reaction, these acids (fatty acids, aliphatic or aromatic) are used. The ratio of the total amount of polybasic acid) to the amount of polyhydric alcohol used should be 7: 1.

 In the esterification reaction, first, a polyhydric alcohol is reacted with an aliphatic dibasic acid and / or an aromatic polybasic acid at a predetermined ratio to perform partial esterification, and then, the partially esterified product is reacted with a fatty acid. Alternatively, the reaction sequence of the acid may be reversed, or the acid may be mixed and subjected to esterification.

 () Dialkyl esters of linear or branched aliphatic dibasic acids (C 1-22 may be used).

Examples of the aliphatic dibasic acids, preferably aliphatic dibasic acids _¾ which can be used an aliphatic dibasic acid shown above (3) include succinic acid, adipic acid, sebacic acid, Undekan acid, dodecanedioic Acid, Carboxyoctadecane Acid, carboxymethyl octadecanoic acid and the like. As the alkyl alcohol component, alcohols having 5 to 8 carbon atoms can be used, and examples thereof include amyl alcohol, hexyl alcohol, heptyl alcohol and octyl alcohol, and isomers thereof. Isoamyl alcohol and isohexyl alcohol are preferred. And octyl alcohol. Specific examples include dioctyl adipate, diisoheptyl adipate, dihexyl sebacate, diheptyl succinate and the like.

 (5) Dialkyl esters of aromatic dibasic acids (having 18 to 26 carbon atoms) can also be used.

 Examples of the aromatic dibasic acid include phthalic acid, isophthalic acid, and derivatives thereof. As the alkyl alcohol component, the above

Preferred alcohols in which the alcohol having 5 to 8 carbon atoms shown in (4) can be used are isoamyl alcohol, isoheptyl alcohol and octyl alcohol. Such diesters include dimethyl phthalate, diisoheptyl phthalate, diisoamyl phthalate and the like.

 (6) As alcohol components, monohydric alcohols selected from methanol, ethanol, propanol, butanol, etc. and their isomers, polyhydric alcohols such as glycerin, trimethylolpropane, etc .; and, for example, ethylenoxide, propylene oxide, butylene oxide Organic carboxylic acid esters using an adduct of 1 to 10 moles, preferably 1 to 6 moles of an alkylene oxide selected from amides, amylenoxides and the like and their isomers can also be used.

As the acid for the alkylene oxide adduct of a monohydric alcohol, the aliphatic dibasic acids and aromatic polybasic acids shown in the above (3) can be used. Further, as the acid for the alkylene oxide adduct of polyalcohol, The linear or branched fatty acids having 3 to 12 carbon atoms shown in (1) can be used.

 As the fatty acid constituting the above-mentioned organic carboxylic acid ester, a linear or branched fatty acid can be used. However, when a branched fatty acid is used, the hydrolysis stability is more excellent, and the hermetic is more preferable. Compatibility with coils and the like can be achieved.

 These organic carboxylic acid esters can be obtained by esterifying alcohols and fatty acids in the presence of an acid catalyst such as phosphoric acid. Normally, the total acid value is 0.1 to 0.5 mg KOH / g, the peroxide value is 0.1 to 5 meq Z kg, the aldehyde value is 0.1 to 5 mg KOH / g, and the bromine number index is 1 to 100 mg / g. 100 g, an ash content of 5 to 50 ppm, and a water content of 300 to 100 ρρηι are obtained.

 However, if the total acid value of the lubricating oil for refrigerators is high, problems such as corrosion occur in the metal parts, and further, the lubricating oil for refrigerators itself is hydrolyzed, so that the function as lubricating oil for refrigerators is reduced. In addition, since refrigerators and the like generally have a motor part disposed in lubricating oil and require high insulation properties, lubricating oil for refrigerators has a total acid value of 0. 0 5 mgKOH / g or less is preferred

 In addition, the peroxide value, aldehyde value, and bromine value index are kept low to further increase the stability of the refrigerant, and the ash content is suppressed to suppress sludge, etc. It is preferable to suppress the water content. Therefore, by refining the above esters obtained by ordinary esterification reaction and adjusting the index indicating the above properties of the ester oil to a range suitable for refrigerating machine oil, a more excellent refrigerating machine oil can be obtained. Can be.

For purification of organic carboxylic acid esters, silica gel, activated alumina, active It is preferable to carry out the contact treatment with charcoal or zeolite. Contact conditions at this time may appropriately determined depending on the species situation, temperature is good preferable carried out in the following 1 oo ^e c.

 Next, polyalkylene glycols usable in the present invention include homopolymers of alkylene glycols such as polyethylene glycol and polypropylene glycol, and copolymers such as alkylene oxides such as ethylene oxide and propylene oxide. And the terminal group may be substituted with a methyl group, an ethyl group, a propyl group, a butyl group or the like. The average molecular weight is usually from 500 to 180; preferably from 800 to 160. If it is less than 500, the compatibility with the refrigerant at high temperatures is high, but the kinematic viscosity is And the thermal stability tends to decrease. If it exceeds 180, the kinematic viscosity is high, but the compatibility with the refrigerant tends to decrease.

 The lubricating oil for refrigerators of the present invention may be added with a viscosity index improver for the purpose of obtaining desired kinematic viscosity and viscosity index required for various refrigerators. Conventional materials can be used, for example, polyolefins (eg, polybutene, poly α-olefin, ethylene-olefin copolymer, etc., including hydrogenated products), polymethacrylates (eg, homopolymers of methacrylate, acrylate, and acrylic acid). , A copolymer containing methacrylic acid as a component), polyisobutylene, polyalkylstyrene, ethylene-propylene copolymer, styrene-gen copolymer, styrene-maleic anhydride copolymer and the like. The compounding amount of these viscosity index improvers is usually 0.1 to 20% by weight, preferably 1 to 10% by weight based on the base oil.

The lubricating oil for refrigerators of the present invention generally has a kinematic viscosity range (at 100) of 2 to 10 O cSt, preferably 2 to 80 cSt. If the temperature is less than 2 cSt, the compatibility with the refrigerant at high temperature is high, but the kinematic viscosity is low and lubrication occurs. The properties and sealing properties are reduced, and the thermal stability also tends to be reduced. If it exceeds 10 O cSt, the compatibility with the refrigerant tends to decrease. However, even within this range, the kinematic viscosity range varies depending on the model used. For example, for refrigerators, it is 2 to 9 cSt, preferably 3 to 7 CSt. For car air conditioners, it is 7-4 O cSt. Also, among car air conditioners, the reciprocating type compressor has a pressure of 7 to 15 cSΐ, preferably 8 to 1 lcSt, and the rotary type compressor has a pressure of 15 to 4 OcSt, preferably 20 to 3 cSt. 5 cSt. In a refrigerator, if it exceeds 9 cSt, there is a problem that the friction loss in the sliding part becomes large.In a reciprocating car air conditioner, if it is less than 7 cSt, the lubricity decreases. If it exceeds, there is a problem that the friction loss in the sliding portion becomes large, and in the case of a rotary-type car air conditioner, if it is less than 15 CSt, there is a problem that the sealing property is deteriorated.

 Additive

Various additives commonly used can be used in the lubricating oil for refrigerators of the present invention. Examples of the antiwear agent include, for example, a general formula (RO) ₃ P = S (where R is an alkyl group, aryl group, phenyl group) Which may be the same or different), for example, a sulfur-based antiwear agent such as trialkylphosphorothionate, triphenylphosphorothionate and alkyldiarylphosphorothionate; Sulfides such as phenyl sulfide, diphenyl disulfide, di-n-butyl sulfide, di-n-butyl disulfide, di-tert-dodecyl disulfide, di-tert-dodecyl trisulfide, etc. Sulfurized oils and fats such as dosperm oil and sulfalide dodipentene, and thiocarbonates such as xanthic disulphide, first-class Zinc alkyl thiophosphate, zinc secondary alkyl thiophosphate, zinc alkyl-aryl thiophosphate, zinc aryl thiophosphate, etc.

Λ Zinc phosphate phosphate-based wear inhibitors. Phosphorus-based antiwear agents include benzyl diphenyl phosphate, aryl diphenyl phosphate, triphenyl renophosphate, tricresino rephosphate, ethinoresphenyl phosphate, tributyl phosphate, dibutyl phosphate, dibutyl phosphate, resin / resin. Phenyl phosphate, dicresyl phenyl phosphate, ethyl phenyl / resiphenyl phosphate, getyl phenyl phenyl phosphate, propyl phenylino phenyl phosphate, dipropyl phenyl phenyl phosphate, tripropyl phenyl phosphate, triethyl phenyl phosphate, Tripropyl phenyl phosphate, butyl phenyl azo phenyl phosphate, dibutyl phenyl phenyl phosphate, tributyl phenyl phosphate Phosphates such as phosphates, phosphites such as trisopropyl phosphite and disopropyl phosphite, hexamethylphosphoric triamide, n-butinole-n-dioctizole phosphinate And di-π-butylhexynolephosphonate, amine dibutylphosphonate, dibutyl phosphoramidate and the like.

 These wear inhibitors may be used alone or in combination of two or more. The use ratio of the antiwear agent is usually from 0.01 to 5% by weight, preferably from 0.1 to 3% by weight, based on the base oil.

Antioxidants can also be used, for example, amine antioxidants such as dioctyldiphenylamine, phenyl-α-naphthylamine, alkyldiphenylamine, 二 -ditrosodiphenylamine, 6-di-butyl valacresol, 4,4′-methylenebis (2,6-di-t-butylphenol), 2,6-di-butyl-α-dimethylamamine paracresol, 2,6- Phenolic antioxidants such as dibutyl phenol, tris (2,4-diphenylphenyl) phosphite, trisnonylphenylphosphite, And phosphorus-based antioxidants such as triphenylphosphite. These may be used alone or in combination of two or more. The proportion of the antioxidant to be used is usually 0.01 to 10% by weight, preferably 0.01 to 1.0% by weight, based on the base oil.

 Corrosion inhibitors can also be used, for example, isostearate, n-octadecylammonium stearate, duomin T-diolate, lead naphthenate, sorbitan oleate, pendus eryslit, oleate, oreile sarcosine And alkyl succinic acid, alkenyl succinic acid, and derivatives thereof. These may be used alone or in combination of two or more. The use ratio of the corrosion inhibitor is usually 0.001 to: 1.0% by weight, preferably 0.01 to 0.5% by weight, based on the base oil.

 An antifoaming agent such as silicone can also be used. The proportion used is usually from 0.0001 to 0.003% by weight, preferably from 0.0001 to 0.001% by weight, based on the base oil.

 Metal deactivators can also be used, for example, benzotriazole, benzotriazole-induced rest, thiadiazole, thiadiazole derivative, triazole, triazole-induced rest, dithiolbamate, etc. These can be used alone. However, two or more kinds can be used in combination. The usage ratio of the metal deactivator is usually from 0.01 to: 0% by weight of the base oil, preferably from 0.01 to: 0% by weight of the base oil.

Further, an antibacterial agent may be used, and examples thereof include succinic acid, succinic acid ester, oleic acid tallow amide, barium sulfonate, and calcium sulfonate. These may be used alone or in combination of two or more. The proportion of the protective agent used is usually from 0.01 to: 0% by weight of the base oil, preferably from 0.01 to: 1.0% by weight. As the stabilizer, 0.1 to 20% by weight of the following can be added.

 Butyl dalicidyl ether, pentyl glycidyl ether, hexyl glycidyl ether, heptyl dalidyl ether, otatyl daricyl ether, nonyl dalicidyl ether, 2-methylpentyl daricyl ether, 2-ethyl hexyl glycidyl ether, 3,5,5-to Glycidyl ethers such as trimethylhexyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, t-butylphenyl dalicydyl ether

 Glycidyl butanoate, Glycidyl pentanoate, Glycidyl hexanoate, Brisidyl heptanoate, Glycidyl octanoate, Glycidyl nonanoate, Glycidyl 2-methylpentate, Glycidyl 2-ethyl hexate , 3,5,5-glycidyl esters such as trimethylhexanoic acid glycidyl ester, vivalic acid glycidyl ester and benzoic acid glycidyl ester

 Epoxidized fatty acid esters

 Epoxy compounds such as styrene oxide, binenoxide, limonene oxide, 3,4-epoxycyclohexyl / remethy / re, and 3,4-epoxycyclohexylca / repoxylate. Preferred polymerization initiator

When fumaric acid ester copolymers are produced using the widely used radical polymerization initiator 2,2'-azobisisob 'thyronitrile (AIBN), post-treatment of the fumaric acid ester copolymer is difficult. This has the problem that precipitates remain even after purification and the polymer is colored. Akira was found. The properties as lubricating oils are better than those of conventional lubricating oils, but further improvements are desired in terms of viscosity index and compatibility with CFC substitutes.

 The present inventor has found that tert-butyl baroxide is preferred as a polymerization initiator for obtaining an alkyl fumarate polymer or copolymer. Here, the fumaric acid alkyl ester polymer or copolymer is defined by the above formula (I)

 (Where R represents a linear lower alkyl group)

 The copolymer, which is a homopolymer or a copolymer having the structural unit represented by, can be any copolymer such as a random copolymer and a block copolymer. Examples of R include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. R may be the same or different.

A polymerization initiator tert - butyl bar oxides, and preferably the amount of against the raw 0 ₄ initiator used 1-5 mol% is too small tends yield is lowered, too much. The kinematic viscosity tends to increase. In order to improve the yield, it is preferable to add the initiator to the polymerization reaction system batchwise or continuously instead of adding it all at once. The polymerization temperature is preferably from 130 to 17 CTC. If the polymerization temperature is lower than this, the yield tends to decrease. If the polymerization temperature is higher than this, the coloration tends to occur. If the reaction time is too short, the yield tends to decrease. Preferred polymerization solvent

A method of radical polymerization after isomerizing radical polymerization and maleic acid di § alkyl ester such dialkyl fumarate esters, Acta P oi yiner ica 39 ( 1988) No. 1, 4 disclosed 5-8 According to this document, the yield of the polymer obtained by these polymerizations has a special alkyl group. Low except for monomers, especially straight-chain alkyl group, for example Π- propyl group, (hereinafter 3 0%) yield is low in the case of having a n- butyl group as an ester group ₄ such polymerization reactions, It is carried out in a solvent such as isopropyl alcohol in the presence of a polymerization initiator such as 2,2'-azobisisobutyronitrile.

 The present inventors have found that when a diester monomer of fumaric acid or maleic acid is polymerized in the presence of a polymerization initiation bar to obtain an alkyl fumarate polymer or copolymer, the polymerization is carried out in a tetrahydrofuran solvent. It was found that a polymer was obtained in high yield, and that the polymer was particularly suitable as a lubricating oil for refrigerators. Here, the alkyl ester fumarate polymer or copolymer is defined by the above formula (I)

 (Where R represents a linear lower alkyl group)

 Or a homopolymer or copolymer having a structural unit represented by The copolymer can be any copolymer such as a random copolymer and a block copolymer. Examples of R include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. R may be the same or different.

 As the polymerization initiator, the above-mentioned known ones can be used. The polymerization initiator is preferably used in a molar ratio of at least 1Z100 to the raw material. In order to improve the yield, the initiator should not be added to the polymerization reaction system at once. It is preferable to add palindrically or continuously. * The polymerization temperature is preferably 60 to 145, and the reaction time is preferably 24 to 72 hours. If the time is too short, the yield will decrease.

The amount of tetrahydrofuran (TH F), when preferably the monomer or 1 Z 5 to 8 (the amount of _β solvents the volume ratio> is too small relative to the raw material Since the kinematic viscosity of the polymer becomes too high, the compatibility with the refrigerant decreases, and when it is too high, the yield tends to decrease.

 When a diester of fumaric acid or maleic acid having a linear lower alkyl group in the ester group is reacted in a tetrahydrofuran solvent in the presence of a polymerization initiator, a polymer can be obtained in high yield. In addition, since this polymer has a wide temperature range compatible with CFC substitute refrigerants and a high viscosity index, it can be used as a lubricating oil for refrigerators using CFC substitute refrigerants to obtain excellent lubricating oils. Can be

 Alternatively, the present inventors have found that it is preferable to use P-xylene as a solvent in the same manner as described above. The obtained polymer has a high viscosity index and has a wide temperature range in which it is compatible with the alternative CFC-based refrigerant.

 Method of adding a radical polymerization initiator

 The present inventors have found that the yield of the polymerization reaction can be improved by adding the radical polymerization initiator in a specific manner. That is, in a method for producing a polymer by polymerizing a dialkyl fumarate or a dialkyl maleate in the presence of a radical polymerization initiator, at least the radical polymerization initiator is added at least over a 2-hour addition time. It is preferable to add the amount more than 23 times the total amount of the radical polymerization initiator at the specific time interval of 1 to 5 of the above-mentioned addition time.

 The total amount of the added radical polymerization initiator (hereinafter sometimes simply referred to as the initiator) is preferably at least 100: 1, more preferably at least 3100 moles to the raw material ester. Ratio. If the total amount is too large, there is no particularly advantageous effect, and it is generally less than 2 to 10 molar ratio.

The present invention is characterized in that the initiator is added to the polymerization reaction system batchwise or continuously, rather than all at once, whereby the yield is favorable. Or 70% or more, especially 80 to 100%.

 The addition of the initiator takes at least 2 hours, preferably 3 to 12 hours. During this addition time, the total amount of initiator is added batchwise or continuously in at least 4 portions, preferably at least 10 portions. Increasing the number of batches will result in a continuous addition. Increasing the number of batches tends to reduce the total amount of initiator.

 It is not necessary to add the same amount of initiator in each batch, but if it is very different, the effect of this embodiment may be lost due to adding a large amount of initiator at once. In a specific time interval corresponding to 1 Z 5 of the initiator addition time, no more than 2 to 3 of the total starting thorn should be added. Preferably, no more than 1 to 5 of the total initiator is added during a specific time interval corresponding to 1 Z 10 of the addition time. In a preferred embodiment, the total amount of the initiator is divided into approximately equal amounts of 10 to 20 times and added at approximately equal time intervals. In industrial mass production, it is operationally easy to add the initiator continuously at a constant flow rate.

 The alkyl group in the starting material dialkyl fumarate and maleic acid dialkyl ester in this embodiment is preferably an alkyl group having 8 or less carbon atoms, particularly 4 or less carbon atoms. When the alkyl group is direct, the effect of this embodiment is more remarkable since the yield was particularly poor in the conventional method.

Known radical polymerization initiators can be used. Polymerization混度preferably 5 0: is at ^{L 6 0: L 8 0 e} C, especially 8 0. After adding all the initiator, it is preferable to continue the reflux stirring while maintaining this temperature. From the start of the addition of the initiator to the termination of the polymerization reaction, preferably for 6 to 40 hours, particularly 10 to 3 hours Take 0 hours

The lubricating oil for refrigerators of the present invention includes, for example, air conditioners for buildings and homes, refrigerators, It can be used as lubricating oil in refrigerators used in refrigeration systems in a wide range of fields such as freezers and car air conditioners.

 Furthermore, the lubricating oil of the present invention can also be added as an additive to lubricating oils for refrigerators based on other substances, for example, organic carboxylic acid esters, polyalkylene glycols, alkylbenzenes, mineral oils and the like.

 Since the lubricating oil for refrigerators of the present invention uses the above-mentioned alkyl fumarate copolymer having a specific structure, it is compatible with alternative Freon-based refrigerants such as hydrogen-containing halogenated hydrocarbons, especially with R134a. Temperature range is wide and viscosity index is high. It is also thermally and chemically stable and has excellent lubricity.

 The following examples illustrate the invention in more detail. In the examples,% indicates% by weight and viscosity indicates kinematic viscosity at 100'C.

 The yield was determined as the ratio of the weight of the residue to the total weight of the starting ester monomer by removing light components from the polymerization reaction system by distillation under reduced pressure.

 The compatibility of each lubricating oil was tested as follows.

 Sample oil and refrigerant (1,1,1,2-tetrafluoroethane, R134a) are collected in a glass tube and mixed at a rate of 15% by volume of the sample oil to a total of 2 nH and mixed. Then, the glass tube was placed in a thermostat having a cooling device, and the separation temperature of the sample oil and the refrigerant at a low temperature was measured. Next, the sample oil and the refrigerant were collected and mixed in another glass tube so that the sample oil became 10% by volume of the total so that the total volume became 2 nH, and the glass tube was placed in a thermostat having a heating device. Then, the separation temperature of the sample oil and the refrigerant at high temperature was measured. In addition, in Example 12 and thereafter, since the measurement is not possible at a temperature below 1 and at a temperature of 80 ° C. or more due to the equipment, the temperature is shown in the table where applicable.

 Example 1

In a 500 ml lolo flask, put 305 raniol (52.5 g) of dimethyl fumarate, which isomerized getylmalate, and 400 ral of p-xylene, A dropping funnel and a cooling pipe were attached and set in an oil bath. In a nitrogen stream, the mixture was stirred using a magnetic stirrer, and the temperature was maintained at 135 ° C while refluxing. The p- of AIBN (2,2-azobisisobutyronitrile) 35-mol (5.8 g) was The xylene solution was added dropwise over 11 hours, and the mixture was heated and refluxed for another 19 hours. Thereafter, the solvent and unreacted substances were distilled off under reduced pressure to obtain 49 g (yield: 94%) of a reaction product.

 Table 1 below shows the viscosity and compatibility of the reaction products.

 Example 2

 A reaction product was prepared in the same manner as in Example 1 except that getyl fumarate was 305 rmol, o-xylene was 250 l, AIBN 50 ranol, the reaction temperature was 135 C, and the reaction time was 4 hours. I got Table 1 below shows the viscosity and compatibility of the reaction products.

 Example 3

 The same equipment as in Example 1 except that getyl fumarate was set to 310ηηιο A, no solvent was used, AIBmOraiBO was used, the reaction temperature was 80, and the reaction time was 8 hours. I got something. Table 1 below shows the viscosity and compatibility of the reaction products.

 Real shawl example 4

 Example 1 The same apparatus as in Example 1 was used, except that getyl fumarate was set at 310 ° C., no solvent was used, {2ηπΙθ}, the reaction temperature was 80, and the reaction time was 8 hours. The reaction product was obtained in the same manner. Table 1 below shows the viscosity and compatibility of the reaction products.

 Real Sharu 5

The same apparatus as in Example 1 was used, except that getyl fumarate was 305HI1IO I, and no solvent was used. C. A reaction product was obtained in the same manner as in Example 1 except that the reaction time was changed to 12 hours. Table 1 below shows the reaction products Shows viscosity and compatibility.

 Example 6

 In the same apparatus as in Example 1, dibutyl fumarate was set to 217 raraol, the reaction temperature was set to 118 ° C., and a solution of AIBN27.5-methyl isobutyl ketone (MIBK) was added dropwise over 12 hours. A reaction product was obtained in the same manner as in Example 1 except that the time was changed to 24 hours. Table 1 below shows the viscosity and compatibility of the reaction products. Example 7

 A mixed oil composed of 63% of the reaction product prepared in Example 4 and 37% of an organic carboxylic acid ester [trade name: P-51 (manufactured by Mobile Oil Co.)] was prepared as a lubricating oil for refrigerators. Table 1 below shows the viscosity and compatibility of the mixed oil.

 Example 8

Example 4 the reaction product of 49% prepared in, and to prepare a Jipentaerisuri Torr and mixed oil consisting of an ester reaction product of 51% of C ₆ acid as a refrigeration lubricant. Table 1 below shows the viscosity and compatibility of the mixed oil.

 Example 9

 A mixed oil composed of 83% of the reaction product prepared in Example 3 and 17% of an organic carboxylic acid ester [trade name: P-51 (manufactured by Mobile Oil Co.)] was prepared as a lubricating oil for a refrigerator. Table 1 below shows the viscosity and compatibility of the mixed oil

 Example 10

 In the refrigerator oil prepared in Example 2, the refrigerator oil prepared in Example 4 was distilled under reduced pressure, and the solid content obtained by cutting the component having a low polymerization degree was 5%. A lubricating oil for a refrigerator was prepared. Table 1 below shows the viscosity and compatibility of the mixed oil

 Example 11

The lubricating oil for refrigerators prepared in Example 2 was mixed with 5% of polymethyl methacrylate having a weight average molecular weight of 12000 to prepare lubricating oil for refrigerators. Table 1 below shows the viscosity and compatibility of the mixed oil.

 Comparative Example 1

 An organic carboxylic acid ester [trade name: P-51 (manufactured by Mobile Oil Co., Ltd.)] was evaluated as a lubricating oil for refrigerators. Table 1 below shows the viscosity and compatibility. Comparative Example 2

The ester reaction product of Jipentaerisuri Torr and c ₆ acid was evaluated as a refrigeration lubricant. Table 1 below shows the viscosity and compatibility.

 Comparative Example 3

Polypropylene glycol dimethyl ether was evaluated as a lubricating oil for refrigerators. Table 1 below shows the viscosity and compatibility.

 As can be seen from this table, the lubricating oil for refrigerators of the present invention has high compatibility with the hydrogen-containing refrigerant, is mature and chemically stable, and has excellent lubricity. Particularly preferred embodiment (A)

 Example 12

 In a 20-mL one-necked flask, 294 mmol of di-butyl fumarate (6

7. lg, 67. Smi) and 1 96 mmol of getyl fumarate (33 8 g, 32.2 ml) (molar ratio 6: 4), and after attaching a cooling tube, this was set in an oil bath. While stirring with a magnetic stirrer holds the al temperature at 60, 2,2' § zone bis I Su Wu Ciro nitrile (AIBN) 20 mmol (3. 8 g) and tetrahydrofuran 30 _{1 1} 1 month 11ぇ Heating and stirring were continued at this temperature for 72 hours. Thereafter, light components were distilled off under reduced pressure to obtain 91.6 g of a polymer. Yield 91%.

 The kinematic viscosity of the obtained polymer was measured, and the viscosity index was determined. A compatibility test was also performed. Table 2 shows the results.

 Example 13

 The amounts of di-butyl fumarate and getyl fumarate were 402 mmol (91.8 g, 92.7 ml) and 45 mmol (7.7 g, 7.3 ml), respectively (molar ratio 9: A polymerization reaction was carried out in the same manner as in Example 12 except for 1), thereby obtaining 89.6 g of a polymer.Yield 90%

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 12, and the viscosity index was determined. The result of a compatibility test was also shown in Table 2. Example 15

 Instead of di-butyl fumarate and getyl fumarate, 190 mmol of di-2-ethylhexyl fumarate (64.7 g, 68.8 ml) and 190 mmol of getyl fumarate (32.8 g, 31. The polymerization reaction was carried out in the same manner as in Example 12 except that 2 ml) was used (molar ratio: 5: 5), whereby 95.6 g of a polymer was obtained. Yield 98%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 12, the viscosity index was determined, and a compatibility test was performed. The results are shown in Table 2. Real shawl example 16

Polymer and prepared in Example 13, the kinematic viscosity at 100 ^e C is 19 C

St is the dimethyl ether of polypropylene glycol, 80:20 (Weight ratio) to obtain a lubricating oil.

 The kinematic viscosity of the obtained lubricating oil was measured in the same manner as in Example 12, and the viscosity index was determined. A compatibility test was also performed. The results are shown in Table 2.

Polymer and prepared in Example 13, 1 00 kinematic viscosity at ^e C is 1 1 C st, the ester reaction product of hexanoic acid and dipentaerythritol, 80: in a ratio of 20 (weight ratio) It was mixed to make a lubricating oil.

 The kinematic viscosity of the obtained lubricating oil was measured in the same manner as in Example 12, and the viscosity index was determined. Table 2 shows the results of the compatibility test.

 In a 20-Omi one-necked flask, 61.0 mmol (105 g, 100 ml) of getyl fumarate was placed, and after attaching a cooling tube, this was set in an oil bath. The temperature was maintained at 8 TC while stirring with a magnetic stirrer, and 70 mmol (11.5 g) of 1 ,,-azobisisobutyronitrile (AIBN) and 10 Oml of methyl ethyl ketone were added. At this temperature

After heating and stirring for 24 hours, light components were distilled off under reduced pressure to obtain 97.8 g of a polymer. Yield 93%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 12, and the viscosity index was determined. A compatibility test was also performed. Table 2 shows the results. Comparative Example 5

In a 20 Oml one-necked flask, 434 mmol of di-n-butyl fumarate (99 g, 10 Oml) was added, and after attaching a cooling tube, this was set in an oil bath, and stirred with a magnetic stirrer. Maintain the temperature at 90 ° C, add 61 mmol (10.0 g) of 2,2'-azobisisobutyronitrile (AIBN) and 80 ml of methyl isobutyl ketone, and at this temperature for 24 hours After heating and stirring, light components were distilled off under reduced pressure, and polymerization was carried out. 84.9 g were obtained. 86% yield.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 12, and the viscosity index was determined. A compatibility test was also performed. Table 2 shows the results. Comparative Example 6

 In a 20-Omi one-neck flask, add 610 mmol of getyl fumarate (10

5 g, 100 ml), and after attaching a cooling tube, it was set in an oil bath. The temperature was maintained at 155 while stirring with a magnetic stirrer, and 70 mmol (11.5 g) of 2,2'-azobisisobutyronitrile (AIBN) and 10 Oml of 0-xylene were added. For 24 hours. After that, light components are distilled off under 压 to obtain polymer 104.

8 g were obtained. Yield 100%.

The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 12, and the viscosity index was determined. A compatibility test was also performed. ₄ Comparative Example Ί shown results in Table 2

 In a 200 mi one-necked flask, 434 mmol of di-n-butyl fumarate (9

9 100ml), attached a cooling tube, and set it in an oil bath. The temperature was maintained at 8 CTC while stirring with a magnetic stirrer, and 2,2'-azobisisobutyronitrile (AIBN) 80 mmol

(13.1 s) and 10 ml of tetrahydrofuran were added, and the mixture was heated and stirred at this temperature for 72 hours. Then, the shoe content is distilled off under high pressure, and the polymer 9

4.1 g obtained 95% yield.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 12, and the viscosity index was determined. A compatibility test was also performed. * The results are shown in Table 2. Comparative Example 8

 In a 200 ml one-necked flask, 499 mmol of di-n-propyl fumarate

(100 g, 100 ml) Set on the bus. While stirring with a magnetic stirrer and keep the temperature 13 5 ^e C, 2,2'- § zone bis I Su Wu Ciro nitrile (AI BN) 70 Mi Rimoru (1 1. 5 g) and P- xylene 10 OML a In addition, ripening and stirring were continued at this temperature for 24 hours. Thereafter, the polymer component was distilled off under reduced pressure to obtain 24.8 g of a polymer. Yield 25%

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 12, and the viscosity index was determined. A compatibility test was also performed. Table 2 shows the results. Comparative Example 9

In a 200 ml one-necked flask, 276 mmol (94 g, 100 ml) of di-2-ethylhexyl fumarate was added, and after attaching a cooling tube, the mixture was stirred with a _φ magnetic stirrer set in an oil bath. While the temperature is 135. Then, 46 mmol (7.6 g) of 2,2'-azobisisobutyronitrile (AIBN) and 250 ml of P-xylene were added, and the mixture was heated and stirred at this temperature for 8 hours. The light components were distilled off under reduced pressure to obtain 54, 8 g of a polymer _{4 with a} yield of 58%.

The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 12, and the viscosity index was determined. A compatibility test was also performed. Table 2 shows the results.

Two

特に好ましい態様 （ B ) 実施例

Particularly preferred embodiment (B) Example

 In a 20-mL one-necked flask, 294 mmol of di-butyl fumarate (6

Add 7.1 g, 67.8 ml) and 196 mmol of getyl fumarate (338 g, 32.2 ml) (molar ratio 6: 4), attach a cooling pipe, and set this in an oil bath. The temperature was raised to 60 while stirring with a magnetic stirrer. C, and 20 mmol (3.8 g) of 2,2'-azobisisobutyronitrile (AIBN) and 3 Oml of tetrahydrofuran were added. The mixture was heated and stirred at this temperature for 72 hours. Distill off the whiskers As a result, 91.6 g of a polymer was obtained. Yield 91%.

 Here, the yield was determined as a ratio of the weight of the residue to the total weight of the starting ester monomer after removing light components from the polymerization reaction system by vacuum distillation.

The obtained polymer was analyzed by Jfi-NMR and ¹³ C-NMR. The results are shown in Figures 1 and 2.

In addition, ¹ H-NMR and ¹³ C-NMR were measured under the following conditions.

 1H-NMR

 Measuring equipment J EO EX 400 400 MHz (manufactured by JEOL Ltd.)

 Measurement solvent C D C 13 / TM S 30 ° C

1 ³ C- 瞧

 Measuring device J EOL EX— 400 100 MHz (manufactured by JEOL Ltd.)

 Measurement solvent CDC 1 / TM S 30

From ¹ "Result of ³ C-NMR in Fig. 2, one 0- CH ₂ of dibutyl fumarate - area ratio of each peak (64 ppm) to equivalent to 67.300, and the fumarate Echiru one O-CH ₂ - Area ratio of peak (61 ppm) corresponding to 42

644 and the number average molecular weight (Mn) measured by vapor pressure measurement (VPO) was 930, the above polymer was represented by the above formula

A copolymer of getyl fumarate and di-n-butyl fumarate having a degree of polymerization of 7.86, having 39 mol% of the repeating unit represented by (V) and 61 mol% of the repeating unit represented by the formula (VI). It turns out that it is a random copolymer》

Next, the kinematic viscosity of the polymer was measured, and the viscosity index was determined. A compatibility test was also performed. Table 3 shows the results. Actual example 19

 The amounts of di-n-butyl fumarate and getyl fumarate were 402 mmol (91.8 g, 92.7 ml) and 45 mmol (7.7 g, 73 ml), respectively, except for a molar ratio of 9: 1. A polymerization reaction was carried out in the same manner as in Example 18. Thus, 89.6 g of a polymer was obtained. 90% yield.

The obtained polymer was analyzed by ¹ H-NMR and ¹³ C-NMR under the same conditions as in Example 18. The results are shown in FIGS.

From the results of ^1vJ C-Nm¾ in Fig. 4, the area ratio of the peak (64ppra) corresponding to _o—CH ₂ — of dibutyl fumarate and the peak corresponding to one O—CH ₂ — of getyl fumarate (61 ppra) area ratio of 6.630, and a number average molecule measured by vapor pressure measurement (VPO)! : Since (Mn) was 1000, the polymer had 6 mol% of the repeating unit represented by the formula (V) and 94 mol% of the repeating unit represented by the formula (VI). It was found that the copolymer was a random copolymer of dimethyl fumarate and di-n-butyl fumarate having a degree of polymerization of 6.79.

 Next, the kinematic viscosity of the polymer was measured in the same manner as in Example 18, and the viscosity index was determined. In addition, a solubility test was also conducted. Table 3 shows the results.

 Comparative Example 10

 In a 20-mL one-neck flask, add 610 mmol of getyl fumarate (10

5g, 100ml), attached a cooling pipe, and set it in an oil bath. The temperature was maintained at 8 CTC while stirring with a magnetic stirrer, and 70 mmol (11.5 S) of 2,2'-azobisisobutyronitrile (AIBN) and 10 Oml of methylethyl ketone were added. The heating and stirring were continued at this temperature for 24 hours.

97.8 g were obtained. Yield 93%. The obtained polymer was analyzed by ¹ H- NMR and 1 ³ C-NHR at the same conditions as in Example 18. The results are shown in FIGS. From these results, it was confirmed that this polymer was a homopolymer of getyl fumarate.

 Next, the kinematic viscosity was measured in the same manner as in Example 18, and the viscosity index was determined. A compatibility test was also performed. Table 3 shows the results.

 Comparative Example 11

434 mmol (99 g, 10 Oml) of di-butyl fumarate was placed in a 20-ml one-necked flask, and a condenser was attached thereto, and then this was set in an oil bath. The temperature was maintained at 6 CTC while stirring with a magnetic stirrer, and 40 mmol (6.57 g) of 2,2'-azobisisopthyronitrile (AIBN) and 40 ml of tetra-t-drofuran were added. _¾ then was continued I 2 hours heating and stirring at a temperature, and distilled light fractions under reduced pressure to obtain a polymer 9 9. 9 g. Yield 100%.

The obtained polymer was analyzed by ¹ H-NMR and ¹³ C-NHR under the same conditions as in Example 18. The results are shown in FIGS. From these results, it was confirmed that this polymer was a homopolymer of di-n-butyl fumarate.

 Next, the number average molecular weight (Mn) was determined to be 840 in the same manner as in Example 18. Further, the kinematic viscosity was measured, the viscosity index was determined, and a compatibility test was also performed.

Table 3 shows the results. ^ Several gfr flat

 Kinematic viscosity,

 Molecular weight cSt Viscosity Refrigerant compatibility

 (Hn) 40. C 100. C index (.c) Example 18 930 1055 51.0 94 -45 to 80

 Example 19 1000 455 33.7 110 -34 to 80

 Comparative Example 10 3090 54.0 -2 -45 to 80

 Comparative Example "840 255 22.0 104 -44 to 80 Preferred polymerization initiator

 Example 20

 In a 100 ml one-necked flask, put 217 mmol of di-n-butyl fumarate (49.5 e, 50 ml), attach a cooling tube, and stir the mixture with a magnetic stirrer set in an oil bath. Was maintained at 145 V, 1 mmol (0.2 ml) of t-butylperoxide (TB PO) was added, and the mixture was heated and stirred at this temperature for 24 hours. Thereafter, light components were distilled off under reduced pressure to obtain a polymer 46.7 e. Polymer was not colored Yield 94%

 The kinematic viscosity of the obtained polymer was measured, and the viscosity index was determined. A compatibility test was also performed. Table 4 shows the results.

 Real Sharu 21

A 200 mi one-necked flask was charged with 402 mmol of di-n-butyl fumarate (91.8 e 92.7 mU and 45 mmol of getyl fumarate (7.7 e, 7.3 ml)) (molar ratio 9: 1). After installing the cooling pipe, it was set in an oil bath, and the temperature was stirred while stirring with a magnetic stirrer. The temperature was kept at 150 ° C., and 2 mmol (0.4 ml) of t-butyl vaginate oxide (TBPO) was added, and the mixture was heated and stirred at this temperature for 72 hours. Thereafter, light components were distilled off under reduced pressure to obtain a polymer 93.3 e. The polymer was not colored. 94% yield.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 20, and the viscosity index was determined. Table 4 shows the results of the compatibility test. Example 22

Instead of di-n-butyl fumarate, 219 mmol (50 e.5 Oml) of di-n-butyl maleate was used, and 1.14 mmol (0.1 ml) of morpholine was further added to the reaction system at first. A polymerization reaction was carried out in the same manner as in Example 20, except for the above. Thus polymer 46. _lambda polymer that was obtained 2 e was not colored. Yield 92%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 20, and the viscosity index was determined. A compatibility test was also performed. Table 4 shows the results. Comparative Example 12

1-necked flask 10 OML, fumarate n- butyl 217 mmol _{(4 9. 5 e. 50 m} l) were charged, after attaching a cooling tube, which was set in an oil bath. The temperature was maintained at 9 CTC while stirring with a magnetic stirrer, and 27.5 mmol (4.5 c) of 2,2'-azobisisobutyronitrile (AIBN) and 2 Oml of tetrahydrofuran were added. Heating and stirring were continued at the temperature for 24 hours. Thereafter, light components were distilled off under reduced pressure to obtain a polymer 49.9 e. Yield 100%. The polymer was colored.

The obtained polymer, in the same manner as in Example 20, the kinematic viscosity was measured, also ₄ was determined viscosity index were also tested for compatibility. Results Comparison _Λ shown in Table 4. Example 13

In a 1 O flask of 20 Oml, 402 mmol of di-n-butyl fumarate (9 1.8, 92.7 ml) and 45 mmol of getyl fumarate (7.7 ε. 7.3 ml) (9: 1 molar ratio), attach the cooling tube, and set it in the oil bath. did. The stirring temperature with a magnetic stirrer was maintained at 6 O ^e C, 2,2' § zone bis I Su Wu Ciro nitrile (AI BN) 20 mmol (3. 8 s) and tetrahydrofuran 3 OML addition, this At 72 ° C. for 72 hours. Thereafter, light components were distilled off under reduced pressure to obtain 89.6 g of a polymer. 90% yield. The polymer was colored.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 20, the viscosity index was determined, and a compatibility test was performed. The results are shown in Table 4. Table 4

Preferred polymerization solvent

 Example 23

In a 200 ml flask, 217 mmol (4.5 e, 50 ml) of di-fl-butyl fumarate was placed, and after attaching a cooling tube, this was put in an oil bath. Set to The temperature was maintained at 60 C while stirring with a magnetic stirrer, and 10 mmol (1.6 g) of 2,2'-azobisisobutyronitrile (AIBN) and 100 ml of tetrahydrofuran were added. The ripening and stirring were continued at this temperature for 72 hours. Thereafter, the shoe content was distilled off under reduced pressure to obtain a polymer 49.6 ε. Yield 100%

 The kinematic viscosity of the obtained polymer was measured, and the viscosity index was determined. A compatibility test was also performed. Table 5 shows the results.

 Example 24

 The polymerization reaction was carried out in the same manner as in Example 23 except that the amount of tetrahydrofuran was changed to 1 Oml using a 100 ml one-necked flask. Thus, 45.1 g of a polymer was obtained. Yield 91%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 23, and the viscosity index was determined. << A compatibility test was also conducted. Table 5 shows the results. Example 25

 Di-n-butyl maleate instead of di-n-butyl fumarate 219 mmol

(50 e, 50 ml), and a polymerization reaction was carried out in the same manner as in Example 23, except that 1.14 mmol (0.1 ml) of morpholine was further added to the reaction system. Thus, a polymer 4.2 e was obtained in a yield of 98%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 23, the viscosity index was determined, and a compatibility test was performed. The results are shown in Table 5. Comparative Example 14

 A polymerization reaction was carried out in the same manner as in Example 24 except that 10 ml of tetrahydrofuran was not added. Thus, 10.9 g of a polymer was obtained. Yield 22%.

The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 23, the viscosity index was determined, and a compatibility test was performed. The results are shown in Table 5. Comparative Example 15 A polymerization reaction was carried out in the same manner as in Example 23, except that 10 O ml of isopropyl alcohol was used instead of tetrahydrofuran as a solvent. Thus, a polymer 33.2 e was obtained in a yield of 67%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 23, and the viscosity index was determined. A compatibility test was also performed. Table 5 shows the results. Comparative Example 16

 A polymerization reaction was carried out in the same manner as in Example 23 except that 100 ml of heptane was used instead of tetrahydrofuran as a solvent. Thus, a polymer 33.2 was obtained. Yield 6%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 23, the viscosity index was determined, and a compatibility test was also performed. The results are shown in Table 5 Comparative Example 18

 A polymerization reaction was carried out in the same manner as in Example 23 except that 100 ml of r-butyrolactone was used instead of tetrahydrofuran as a solvent. Thus, 28.7 g of a polymer was obtained. Yield 57%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 23, and the viscosity index was determined. Table 5 shows the results of the compatibility test. Comparative Example 19

 The polymerization reaction was carried out in the same manner as in Example 23 except that toluene was used as the solvent in place of tetrahydrofuran, and 10 O ml of toluene was used. Thus, polymer 26.7ε was obtained in a yield of 54%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 23, the viscosity index was determined, and a compatibility test was performed. The results are shown in Table 5. Comparative Example 20

The polymerization reaction was carried out in the same manner as in Example 23 except that 100 ml of o-xylene was used instead of tetrahydrofuran as a solvent. 6.2 e was obtained. Yield 5 3%,

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 23, and the viscosity index was determined. A compatibility test was also performed. The results are shown in Table 5 Comparative Example 21

 A polymerization reaction was carried out in the same manner as in Example 23 except that 100 ml of methylethyl ketone was used instead of tetrahydrofuran as a solvent. Thus, a polymer 31.2ε was obtained. Yield 63%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 23, and the viscosity index was determined. Table 5 shows the results of the compatibility test. Comparative Example 22

 The polymerization reaction was carried out in the same manner as in Example 23, except that ethanol was used as the solvent instead of tetrahydrofuran, and 100 O ml was used. Thus, polymers 34 and 2e were obtained. Yield 69%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 23, the viscosity index was determined, and a compatibility test was also performed. The results are shown in Table 5 Comparative Example 23

 A polymerization reaction was carried out in the same manner as in Example 23 except that 100 ml of n-butanol was used instead of tetrahydrofuran as a solvent. Thus, a polymer 23.8 e was obtained. Yield 48%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 23, and the viscosity index was determined. A compatibility test was also performed. The results are shown in Table 5 Comparative Example 24

 The polymerization reaction was carried out in the same manner as in Example 23 except that benzene (10 O ml) was used instead of tetrahydrofuran as a solvent, and thus 31.7 g of a polymer was obtained. Yield 64%

The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 23. The viscosity index was determined. A compatibility test was also performed. Table 5 shows the results. Table 5 shows that high yield was achieved by using tetrahydrofuran.

Five

(Note) THF == tetrahydrofuran, tributylamine = isopropyl alcohol, ρ-χγ = ρ-xylene, GBL = r-petit mouth ratatatone, o-XY = o-xylene HEK = methylethyl ketone, Et0H = ethanol, Bu0H = n-butanol Example 26

 In a 20 Oml one-necked flask, di-n-butyl fumarate (21.7 mmol, 49.5 e.50 ml) was placed, and after attaching a cooling tube, this was set in an oil bath. The temperature was maintained at 60 while stirring with a magnetic stirrer, and 100 mmol (1.6 ε) of 2,2′-azobisisobutyronitrile (AIBN) and 100 ml of Ρ-xylene were added. Heating and stirring were continued at the temperature for 72 hours. Thereafter, light components were distilled off under reduced pressure to obtain a polymer 33.7ε. Yield 68%.

 The kinematic viscosity of the obtained polymer was measured, and the viscosity index was determined. A compatibility test was also performed. Table 6 shows the results.

 Example 27

 A polymerization reaction was carried out in the same manner as in Example 26, except that the amount of P-xylene was changed to 10 ml using a 100 ml one-necked flask, thereby obtaining 35.1 g of a polymer. Yield 71%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 26, and the viscosity index was determined. A compatibility test was also performed. The results are shown in Table 6. Example 28

Instead of di-n-butyl fumarate, di-n-butyl maleate (219 mmol, 50 e, 50 ml) was used. First, 1.14 mmol (0.1 ml) of morpholine was further added to the reaction system. A polymerization reaction was carried out in the same manner as in Example 26 except for the above. Thus, a polymer 32.5 _e was obtained.Yield 65%

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 26, and the viscosity index was determined. A compatibility test was also performed. Table 6 shows the results. Comparative Example 26

The polymerization reaction was carried out in the same manner as in Example 26 except that 100 ml of isopropyl alcohol was used instead of P-xylene as the solvent. The product 33, 2e was obtained. Yield 6%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 26, the viscosity index was determined, and a compatibility test was also performed. Table 6 shows the results. Comparative Example 27

 The polymerization reaction was carried out in the same manner as in Example 26 except that o-xylene 10 Oml was used instead of Ρ-xylene as a solvent. Thus, a polymer 26.2 was obtained. Yield 53%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 26, and the viscosity index was determined. A compatibility test was also performed. Table 6 shows the results. Comparative Example 28

 The polymerization reaction was carried out in the same manner as in Example 26 except that 100 ml of ethanol was used instead of P-xylene as the solvent. Thus, a polymer 34.2 e was obtained. Yield 69%.

 The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 26, and the viscosity index was determined. A compatibility test was also performed. Table 6 shows the results. Comparative Example 29

 The polymerization reaction was carried out in the same manner as J26, except that n-butanol 10 O ml was used instead of P-xylene as a solvent. The polymer 23.8 ε was thus obtained in a yield of 48%.

The kinematic viscosity of the obtained polymer was measured in the same manner as in Example 26, the viscosity index was determined, and a compatibility test was also performed. Table 6 shows the results. Table 6 shows that a high viscosity index can be achieved by using Ρ-xylene. 6

(Note) p-XY = ρ-xylene, THF = tetra-t-drofuran, toluene = isop pill alcohol, o-XY = o-xylene, EtOH = ethanol, BuOH = n-butanol Addition of radical polymerization initiator

 Example 29

 In a 10 Oml one-necked flask, getyl fumarate 305 (B niol (52.5 e,

50ml), attach a dropping funnel and a condenser, and keep the temperature at 135 with stirring with a magnetic stirrer set in an oil bath. 2,2'-azobisisobutyronitrile (AIBN) 1 Om mol (1.6 e ) In tetrahydrofuran (20 ml) was added dropwise over 4 hours, and heating was continued for another 20 hours. Thereafter, the shoes were distilled off under reduced pressure to obtain a polymer 42 e (yield 80%). Number average molecular weight (Mn) by vapor pressure measurement (VPO) = 840 Example 30

 The same operation as in Example 29 was carried out except that the reaction temperature was 145 ° C. Polymer

47 e was obtained (90% yield). Mn = 840

 Example 31

 Getyl fumarate 30 5 m πιθΙ (52.5 ^,

50 ml) and 5 Oml of ρ-xylene were added, a dropping funnel and a cooling tube were attached, and the mixture was set in an oil bath. While stirring and refluxing with a magnetic stirrer, keep the temperature at 135 ° C, and p-xylene of 2,2'-azobisisobutyronitrile (AIBN) 35 ID mo! (5.8 s) (50 ml ) The solution was continuously added dropwise over a period of 12 hours in a fixed amount, followed by heating and refluxing for another 12 hours. Thereafter, the shoes were distilled off under reduced pressure to obtain 57 g of a polymer (yield 100%). Mn =

570

 Example 32

 Example 31 was repeated except that the xylene position was 10 Oml. 52 g of a polymer was obtained (100% yield). Mn = 570

 Example 33

 Example 31 was repeated except that the amount of D-xylene was 20 Oml. 54 g of a polymer was obtained (100% yield). Mn = 520

 Example 34

Example 31 was repeated except that the amount of P-xylene was set to 40 Oml and heating and refluxing were continued for 19 hours after completion of the addition of AIBN, to obtain a polymer 49.1 _e (yield 94%). Mn = 440

 Example 35

 Example 31 was repeated except that 0-xylene 5 Oml was used instead of P-xylene and the reaction temperature was 145 ° C. Polymer 54e was obtained (yield 100%).

Realba example 36 Example 31 was repeated except that 2-butanone (MEK) 5 Oml was used instead of p-xylene and the reaction temperature was 80 eC. 48.8 e of a polymer was obtained (yield: 93%).

 Example 37

 Example 31 was repeated except that 50 ml of 4-methyl-2-pentanone (MIBK) was used instead of P-xylene, and the reaction temperature was set at 118. Polymer 54e was obtained (yield 100%).

 Example 38

Example 31 was repeated except that cyclohexanone 5 Oml was used in place of P-xylene and the reaction temperature was set to 150. 52.5 _e of a polymer was obtained (yield: 100%).

 Example 39

Example 35 was repeated except that di-n-butyl fumarate 21.7 inmol (49.5 _e ) was used as the starting ester and the amount of AIBN was 27.5 ml (4.5 e). e was obtained (100% yield).

 Example 40

Example 31 was repeated except that 310 mmol (53.5 _e , 50 ml) of getyl maleate was used as the starting ester, and 1.14 mmol (0.1 mi) of morpholine was further added to the reaction system first. Polymer 53e was obtained (100% yield). Comparative Example 30

 10 Omole of 305 ml (52.5 e, 50 ml) of getyl fumarate was placed in a three-necked flask, a condenser was attached, and the flask was set in an oil bath. Stir with a magnetic stirrer, keep the temperature at 135 while refluxing, add 5 mmol (8.2 e) of 1Λ-azobisisobutyronitrile (AIBN) at a time, and continue heating and refluxing for -12 hours. After that, light components are distilled off under reduced pressure to obtain a polymer.

36 e was obtained (68% yield). Comparative Example 31

A 305 in niol fumarate (52.5 ^, 50 ml) and 25 ml of xylene were placed in a 30 Oml four-necked flask, a cooling tube was attached, and the flask was set in an oil bath. And Sagu拌a magnetic stirrer, keeping the temperature at 135 ^e C under reflux, was added ΑΙΒΝ the (2,2' § zo-bis isoprenyl Ciro nitrile) 50 m mol (8.2g) in one portion, continued heated to reflux for 12 hours Was. Thereafter, the polymer was distilled off under reduced pressure to obtain 20.4 g of a polymer (yield: 38%).

 Comparative Example 32

 Comparative Example 30 was repeated except that 250 ml of 0-xylene was used instead of P-xylene and the reaction temperature was changed to 145. Polymer 35.5 e was obtained (yield 68%).-Comparative Example 33

 Comparative Example 30 was repeated except that 25-ml of 2-butanone (MEK) was used instead of P-xylene and the reaction temperature was set to 80. << Polymer 23.5 e was obtained (yield: 45%) .

 Comparative Example 34

P- xylene using 4-methyl-2-pentanone (HIBK) 25 Oml instead of, except that the reaction temperature was 1 18 ^e C, to obtain a polymer 14. 7 g of repeated Comparative Example 30 (yield Rate 28%).

 Comparative Example 35

 A polymer 21.6 e was obtained by repeating Comparative Example 30 except that cyclohexanone 25 Oml was used instead of P-xylene and the reaction temperature was set to 155 (yield 43%).

 Example 41

In a 50 Oml four-necked flask, put 305 IB mol (52.5 e) of p-xylene and 40 Oml of p-xylene in a four-necked flask, attach a condenser, and set it in an oil bath. Suspended with a magnetic stirrer, keep the temperature at 135 C while refluxing, and add 2,2-azobisisobutyronitrile (AIBN) 5 il) ilio l (0.82 g-) for about 4 hours. Each time, 7 times, that is, a total of 35 ml was added over 30 hours, and then light components were distilled off under reduced pressure to obtain a polymer 37.5 e (yield 71 %).

 Industrial applicability

 The lubricating oil for refrigerators of the present invention can be used as lubricating oil in refrigerators used in refrigeration systems in a wide range of fields, such as air conditioners for buildings and homes, refrigerators, freezers, car air conditioners, and the like.

 Furthermore, the lubricating oil of the present invention can also be added as an additive to lubricating oils for refrigerators based on other substances, for example, organic carboxylic acid esters, polyalkylene glycols, alkylbenzenes, mineral oils and the like.

 Since the lubricating oil for refrigerators of the present invention uses the above-mentioned alkyl fumarate copolymer having a specific structure, it is compatible with alternative Freon-based refrigerants such as hydrogen-containing halogenated hydrocarbons, especially with R134a. Temperature range is wide and viscosity index is high. It is also thermally and chemically stable and has excellent lubricity.

- Five

Claims

 The scope of the claims  The lubricating oil for a refrigerator contains a repeating unit represented by the following general formula (I) and, if desired, a fumarate ester polymer mainly composed of a repeating unit represented by the following general formula (IT). Lubricating oil for refrigerators COO ₁ CH—— CH (I) CO OR ₁ —— R, 2 (E) wherein each can be the same or different from each other, straight or branched C ₁ -C. Selected from the group consisting of alkyl groups, aryl groups, and terminally substituted or unsubstituted polyalkylene oxide residues; each R ₂ can be the same or different from each other, and comprises an alkylene group and a substituted alkylene group Selected from the group; at least two repeating units (I) and at least the same number as the linear repeating units (I) in the polymer, and the repeating unit (（) may not be present. 2. —In the general formula (I), represents a straight-chain or branched -Co alkyl group (including an alkyl group), preferably a -C ₆ alkyl group; encompasses), preferably phenylene group or a cresyl group; terminal substituted or unsubstituted Helsingborg alkylene O key rhino Dozanmoto, preferably of formula - (ΑΟ) χ - X _[here Α ethylene, propylene or butylene group in, X is a hydrogen atom or _1-4 alkyl le group, X is one represented by an integer of 1 to 4], - in general formula (E), R click is a substituted or unsubstituted alkylene group (Including an aralkyl group), preferably a C ₂ -C ₁₂ linear, branched or substituted with a cycloalkylene group or an oxoalkylene group. 2. The lubricating oil for a refrigerator according to claim 1, wherein the lubricating oil is ethylene, propylene, butene and styrenes. 3. A claim wherein R ^ j in the general formula (I) is two or more groups selected from straight-chain or branched ~ C ₉ alkyl, and the polymer does not contain a repeating unit (Π). 2. The lubricating oil for a refrigerator according to item 1 above.  4. The lubricating oil for refrigerators according to claim 1, wherein the proportion of the repeating unit (Π) in the polymer is 30 mol% or less.  5. The lubricating oil for a refrigerator according to claim 1, wherein the kinematic viscosity of the polymer is in the range of 2 to 100 OcSt (at 100). 6. The lubricating oil for a refrigerator according to claim 1, wherein the number average molecular weight of the polymer is from 400 to 300. 7. The refrigeration according to claim 1, further comprising at least one selected from the group consisting of an organic carboxylic acid ester and a polyalkylene glycol, which has a kinematic viscosity of 2 to 3 O cSt at 100. Lubricating oil for machine. 8. Repeating unit (I) is 1〗 repeatedly Unit 5 0-9 repeating units 1-5 0 molar% is Echiru group and R is a straight or branched C ₃ ~ ₈ alkyl group The lubricating oil for a refrigerator according to claim 1, wherein the lubricating oil comprises 9 mol%, and the repeating unit (Π) comprises 0 to 20 mol% of the whole copolymer component. 9. The refrigeration according to claim 8, further comprising at least one selected from the group consisting of an organic carboxylic acid ester and a polyalkylene glycol, wherein the kinematic viscosity at 9-10 CTC is 2-3 O cSt. Lubricating oil for machine. 10. The repeating unit (I) is composed of 5 to 45 mol% of the repeating unit in which I is an ethyl group and 95 to 55 mol% of the repeating unit in which is a linear or branched butyl group. Coalescing does not contain a repeating unit (Π) and 800 2. The refrigerator according to claim 1, wherein the refrigerator has a number average molecular weight of from 300 to 300. Lubricant. 1.100 kinematic viscosity at ^e C is 2 to 3 ocst, organic carboxylic Sane ester and refrigerator further claims paragraph 10, wherein containing one at least selected from the group consisting of polyalkylene glycol For lubricating oil. 2. A fumar characterized by containing 5 to 45 mol% of the structural unit represented by the following formula (V) and 95 to 55 mol% of the structural unit represented by the following formula (VI), and having a molecular weight of 800 to 300,000. Acid ester copolymer CH-

(V) COOCo H ₅ COOC ^ Ho  CH CH (VI) COOC ₄ Ho