JP2000128966A - Polyester resin for adhesion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermally adhesive resin having a low melt viscosity, having excellent adhesivity also on thermal adhesion under the same conditions, and corresponding to environmental problems. SOLUTION: This polyester resin for adhesion satisfies the following requirements. (1) Aromatic dicarboxylic acids are contained in an amount of >=50 mol.% based on the total amounts of all carboxylic acid components. (2) A weight-average mol.wt. is 5,000-20,000. (3) A compound of the following general formula (a) is contained in an amount of 10-60 mol.% per 100 mol.% of the total amount of all the carboxylic acid components and all glycol components. (a) X-Y-Z [X is a functional group containing one or more carbon atoms, and is the residue of a compound having a mol.wt. of <=50 and a melting point of <=100 deg.C, when Z is hydrogen atom (H); Y is O, S or N-R (R is hydrogen atom or an arbitrary monovalent group); Z is a residue containing two or more groups comprising hydroxyl groups, carboxyl groups, or the like].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a thermosetting resin useful as a vehicle for paints, inks, coatings, adhesives, toners, image receiving layers, etc., or as a processing agent for fibers, films, paper products and the like. The present invention relates to a polyester resin having excellent adhesiveness and a method for producing the same.

[0002]

2. Description of the Related Art High molecular weight polyesters are known to exhibit excellent mechanical properties. This is due to the high cohesive force between molecules of the high molecular weight polyester and the high entanglement density. ing. Regarding the adhesive property, it is necessary to perform heating until the melt viscosity becomes sufficiently low to secure the adhesive property at the interface.
By simply adjusting the value, there is a possibility that a problem may occur in terms of blocking resistance and the like, so that it cannot be said that it is a sufficient means for achieving both mechanical properties and adhesiveness. On the other hand, there is a method of using an alkylene oxide adduct of a bisphenol compound such as bisphenol A, bisphenol F or bisphenol S as a raw material for lowering the melt viscosity without lowering the Tg. Regarding the characteristics of polyesters containing bisphenol compounds, it is mentioned that despite the high glass transition temperature, good thermal adhesion is obtained, and taking advantage of this characteristic, alkylene oxide adducts to bisphenol compounds are used for the purpose of adhesion. It is used for a wide range of applications.

[0003] In recent years, however, effects of these compounds on the environment and the human body have been reported, and these bisphenol compounds are one of the target compounds. In response to the reduction in the use of bisphenol compounds, the development of polyesters containing alternative materials was required.
As described above, it is becoming difficult to use phenolic compounds in terms of environmental problems.However, there is no suitable alternative raw material, and it is necessary to consider reducing the melt viscosity without lowering the Tg from the viewpoint of the molecular structure of the polyester. Was.

[0004]

SUMMARY OF THE INVENTION The present invention relates to the above-mentioned environmental problems and problems relating to thermal adhesion and blocking resistance, that is, high Tg, low melt viscosity and low or no harmful bisphenol compounds. It is intended to provide a molecular weight polyester.

[0005]

Means for Solving the Problems The present inventors have studied the compatibility between mechanical properties and thermal adhesiveness, and found that a structure in which the mobility of the polyester chains is increased without lowering the entanglement density during melting of the polyester molecular chains. The present invention has been found to be possible by introducing a low-melting point compound group having a molecular weight that can be recognized as a side chain while keeping the distance between ester bonds short. That is, the present invention is a thermoadhesive polyester resin satisfying the following requirements. (1) The total carboxylic acid component contains at least 50 mol% of an aromatic dicarboxylic acid. (2) The weight average molecular weight is 5,000 to 200,000. (3) The compound represented by the following general formula (a) is a total carboxylic acid component and a total glycol. When the total amount of the components is 100 mol%, the content is 10 to 60 mol%. (A) XYZ X: a functional group containing carbon, and when Z is a hydrogen atom (H), the molecular weight is 50 or more, and the melting point is 100 ° C.
It represents the residue of the following compound. Y: O, S, NR (R represents a hydrogen atom or any monovalent group). Z: any one of a hydroxyl group, a carboxyl group, etc.
Represents a residue containing at least one

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Each section of the present invention will be described below. (Polyester resin) The copolymerized polyester resin in the present invention has a molecular weight of 5,000 to 200,000 and is characterized by containing at least 50 mol% of an aromatic dicarboxylic acid in all carboxylic acid components. When the amount of the aromatic dicarboxylic acid is less than 50 mol%, the adhesion to the substrate and the mechanical properties are reduced. If the aliphatic dicarboxylic acid exceeds 50 mol%, the aliphatic ester bond has a lower hydrolysis resistance than the aromatic ester bond, so that the degree of polymerization of the polyester decreases during the storage period. May be invited.

The aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 5-sodium sulfoisophthalic acid and the like. As aliphatic dicarboxylic acids, succinic acid, adipic acid, azelaic acid,
Sebacic acid, dodecanedioic acid, dimer acid, and the like.Examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, and acids thereof. Anhydrous,
Fumaric acid, maleic acid, maleic anhydride, itaconic acid,
Citraconic acid, 2,5-norbornene dicarboxylic anhydride,
Examples thereof include tetrahydrophthalic anhydride. Furthermore, p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid, or hydroxycarboxylic acids such as hydroxypivalic acid, γ-butyrolactone, and ε-caprolactone can be used if necessary. Of these, aromatic dicarboxylic acids and alicyclic dicarboxylic acids are preferred because they have the effect of increasing Tg. Among the aliphatic carboxylic acids, those containing a long-chain alkyl group such as dimer acid lower the melt viscosity, but at the same time lower the Tg. Therefore, it is preferable to minimize the amount of the aliphatic carboxylic acid used.

On the other hand, the glycol component is composed of an aliphatic glycol having 2 to 10 carbon atoms and / or an alicyclic glycol having 6 to 12 carbon atoms and / or an ether bond-containing glycol. Examples of the aliphatic glycols of Formulas 2 to 10 include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,2-butanediol.
1,3-butanediol, 2,3-butanediol, 1,5-pentaneddiol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,6-hexanediol , 3-methyl-1,5-pentaneddiol, 1,9-nonanediol, 2-ethyl-2-butylpropanediol, neopentyl glycol hydroxypivalate, dimethylol heptane, glycerin monoallyl ether, trimethylol Propane monoallyl ether, dimer diol, hydrogenated dimer diol, and the like, having 6 to 12 carbon atoms
Examples of the alicyclic glycols include 1,4-cyclohexanedimethanol, tricyclodecanedimethylol, cyclohexanediol, alkylene oxide adducts of bisphenols, and hydrogenated bisphenol A.

Examples of ether bond-containing glycols include diethylene glycol, triethylene glycol, dipropylene glycol and the like. Polyethylene glycol, polypropylene glycol and polytetramethylene glycol may be used if necessary. As other glycols, polycaprolactone diol, polyvalerolactone diol, and the like can be appropriately used. The combination of the raw material having a side chain of the present invention and the alkylene oxide adduct of bisphenols has the effect of lowering the melt viscosity without lowering the Tg, but in consideration of the effect on the environment, the alkylene oxide adduct of bisphenols is considered. Use of 5
Mol% or less, preferably 2 mol% or less, and most preferably 0 mol%.

[0010] Particularly preferably used glycols include dimer diol, hydrogenated dimer diol, polypropylene glycol and the like. These compounds are effective in lowering the melt viscosity, and their use conforms to the purpose of the present invention, but on the other hand, the amount used is limited because they lower the adhesiveness. Significant effects can be obtained by introducing the side chain of the present invention and using these glycols in combination. The amount used is preferably 0.1 to 30 mol%, but it is desirable to keep the copolymerization amount to about 0.1 to 0.5 mol% because it causes a decrease in the adhesiveness as described above.

The polyester resin of the present invention is characterized by having a substantially linear structure. In order to have a substantially linear structure, it is characterized by containing almost no trifunctional or higher polyvalent carboxylic acid and polyvalent polyol. Examples of trifunctional or higher functional components include (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, glycerin, trimethylolethane, and trimethylolpropane. These increase only the melt viscosity without increasing Tg. Usage is 1
It is preferably at most 0 mol%, but most preferably 0 mol%.

In the present invention, the polyester is a compound represented by the following general formula (a):
〜60 mol%. (A) XYZ X: a functional group containing carbon, and when Z is a hydrogen atom (H), the molecular weight is 50 or more, and the melting point is 100 ° C.
It represents the residue of the following compound. Y: O, S, SO2, NR (R represents a hydrogen atom or any monovalent group). Z: any one of a hydroxyl group, a carboxyl group, etc.
Represents a residue containing at least one

As a residue of a compound which is a functional group containing carbon and has a molecular weight of 50 or more and a melting point of 100 ° C. or less when Z is a hydrogen atom (H), Z is represented by H When expressed in the form of phenols, alkylphenols such as phenol, methylphenol and ethylphenol, alkoxyphenols such as methoxyphenol, various substituted phenol compounds, benzyl alcohols, aliphatic alcohols having 4 or more carbon atoms, Primary or secondary of various thiophenols, aliphatic thiols, aniline, etc.
Aromatic amines, primary or secondary aliphatic amines having 4 or more carbon atoms, benzylamines, and the like.

Examples of the residue containing at least two of a hydroxyl group, a carboxyl group and the like include a 2,3-dihydroxypropyl group and a dicarboxy-substituted (arbitrary position) alkyl group. Examples of the method for synthesizing these compounds include a method in which the above (thio) phenol, (thio) alcohol, amines are reacted with epichlorohydrin or glycidol, a compound containing two or more of a halogenated hydroxyl group, a carboxyl group, or the like. There is a method of reacting with amines. Further, the thioether compound obtained after the reaction can be oxidized to a sulfoxide.

Specific compounds include, for example, Ph-OC
_{H 2 -CH (OH) -CH 2} OH (3- _{phenoxy-1,2-propanediol) Ph-N (CH 3)} -CH 2 -CH (OH) -CH 2 OH (2,3- dihydroxypropyl methyl _{phenylamine) Ph-CH 2 -Ph-O} -CH 2 -CH (OH)
-CH ₂ OH (3- (p-benzylphenyloxy) -1,2-propanediol) p-CH ₃ O-Ph-O-CH ₂ -CH (OH) -CH ₂ OH (3- (p-methoxy Phenyloxy) -1,2-propanediol) p-CH ₃ -Ph
_{-O-CH 2 -CH (OH)} -CH 2 OH (3- (p- methylphenyl oxy) -
1,2-propanediol) Ph-O-Ph-O -CH 2 -CH (OH) -CH 2 OH
(P- phenoxyphenyl phenyl-2,3-dihydroxypropyl _{ether) Ph-SO 2 -CH 2 -CH} (OH) -CH 2 OH (2,3- dihydroxypropyl phenyl _{sulfoxide) CH 3 (CH 2) nO} -CH 2 -CH (O
H) -CH ₂ OH (2,3- dihydroxypropyl alkyl _{ether) CH 3 (CH 2) nN} (CH 3) -CH 2 -CH (OH) -CH 2 OH (2,3- dihydroxypropyl alkyl phenyl amine) And the like.

The compound represented by the general formula (a) is contained in an amount of 2 to 60 mol% when the total amount of all carboxylic acid components and all glycol components of the polyester is 100 mol%. Preferably 5 to 50 mol%, more preferably 10
４０40 mol%. When the total diol component is 100 mol%, it is preferable that the diol represented by the general formula (a) be contained in an amount of 5 to 90 mol% based on the total diol. It is more preferably from 10 to 80 mol%, particularly preferably from 20 to 70 mol%. When the compound represented by the general formula (a) is 2 mol% or less when the total amount of all carboxylic acid components and all glycol components of the polyester is 100 mol%, or the diol represented by the general formula (a) Is less than 5 mol% when the total diol component is 100 mol%, the effect of lowering the melt viscosity is reduced. If these exceed the upper limit, it becomes difficult to increase the molecular weight during the production of the polyester.

The polyester resin in the present invention has a weight average molecular weight in the range of 5,000 to 200,000, preferably in the range of 7000 to 180,000, and more preferably in the range of 8,000 to 150,000. . If the weight average molecular weight is 5000 or less, various physical properties are reduced, and
When the weight average molecular weight is 200,000 or more, the effect of lowering the melt viscosity by introducing a side chain is reduced.

(Other Additives) The polyester resin in the present invention can be used as it is, but by blending a crosslinking agent (curing resin) and carrying out baking hardening, higher heat resistance, solvent resistance and water resistance can be obtained. Sex can be expressed. Examples of the crosslinking agent include a phenol formaldehyde resin, an amino resin, a polyfunctional epoxy compound, a polyfunctional isocyanate compound and various blocked isocyanate compounds thereof, and a polyfunctional aziridine compound.

Examples of the phenol resin include formaldehyde condensates of alkylated phenols and cresols. Specifically, alkylated (methyl, ethyl, propyl, isopropyl, butyl) phenol, p-tert-amylphenol, 4,4'-sec-butylidenephenol, p-tert-butylphenol, o-, m-, p -Cresol, p-cyclohexylphenol, 4,4'-isopropylidenephenol, p-nonylphenol, p-octylphenol, 3-pentadecylphenol, phenol, phenyl-o-cresol, p-phenylphenol,
Formaldehyde condensates, such as xylenol.

Examples of the amino resin include formaldehyde adducts such as urea, melamine and benzoguanamine.
Further, there may be mentioned alkyl ether compounds of these alcohols having 1 to 6 carbon atoms. Specifically, methoxylated methylol urea, methoxylated methylol
N, N-ethylene urea, methoxylated methylol dicyandiamide, methoxylated methylol melamine, methoxylated methylol benzoguanamine, butoxylated methylol melamine, butoxylated methylol benzoguanamine and the like, preferably methoxylated methylol melamine, butoxylated methylol melamine, and methylol Benzoguanamine, which can be used alone or in combination.

Examples of the epoxy compound include diglycidyl ether of hydrogenated bisphenol A and oligomers thereof,
Diglycidyl orthophthalate, diglycidyl isophthalate, diglycidyl terephthalate, diglycidyl p-oxybenzoate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl succinate, adipine Acid diglycidyl ester, sebacic acid diglycidyl ester, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-
Hexanediol diglycidyl ether and polyalkylene glycol diglycidyl ethers, triglycidyl trimellitate, triglycidyl isocyanurate, 1,4-diglycidyloxybenzene, diglycidyl propylene urea, glycerol triglycidyl ether, trimethylolpropane triglycidyl Examples include ether, pentaerythritol triglycidyl ether, and triglycidyl ether of a glycerol alkylene oxide adduct.

Further, as the isocyanate compound, there are aromatic and aliphatic diisocyanates and trivalent or higher polyisocyanates. Either low molecular weight compounds or high molecular weight compounds may be used. For example, tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate or trimers of these isocyanate compounds, and excess of these isocyanate compounds And the amount of low molecular active hydrogen compounds such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine or various polyester polyols, polyether polyols, polyamides Anti-polymer active hydrogen compounds It includes terminal isocyanate group-containing compounds obtained by.

The isocyanate compound may be a blocked isocyanate. As the isocyanate blocking agent, for example, phenol, thiophenol,
Phenols such as methylthiophenol, cresol, xylenol, resorcinol, nitrophenol, chlorophenol, oximes such as acetoxime, methylethylketoxime, and cyclohexanone oxime; alcohols such as methanol, ethanol, propanol and butanol; ethylene chlorohydrin; Halogen-substituted alcohols such as 3-dichloro-2-propanol,
Tertiary alcohols such as t-butanol and t-pentanol; lactams such as ε-caprolactam, δ-valerolactam, γ-butyrolactam, and β-propyllactam; and other aromatic amines and imides , Active methylene compounds such as acetylacetone, acetoacetate, and malonic acid ethyl ester, mercaptans,
Imines, ureas, diaryl compounds and sodium bisulfite are also included. The blocked isocyanate can be obtained by subjecting the above isocyanate compound, isocyanate compound and isocyanate blocking agent to an addition reaction by a conventionally known appropriate method. These crosslinking agents may be used in combination with a curing agent or an accelerator. In addition, these features, especially from the point of low melt viscosity, not only hot melt adhesive, heat sealing resin, when used as an electrophotographic toner or thermal transfer recording ink ribbon binder, thermal transfer recording image receiving layer Can be used as a resin having excellent fixing characteristics and transfer speed.

[0024]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. In the examples, "parts" means "parts by weight", and
"" Means weight%. Each measurement item followed the following method.

(1) Reduced viscosity 0.01 g of a polyester resin was dissolved in 25 cc of a mixed solvent of phenol / tetrachloroethane (weight ratio: 6/4) and measured at 30 ° C.

(2) Glass transition temperature (Tg) Measured at a heating rate of 20 ° C./min using a differential scanning calorimeter (DSC). The sample was prepared by crimping 5 mg of a sample in an aluminum holding lid type container.

(3) Melt viscosity The melt viscosity at 130 ° C. was determined by a flow tester.

(4) Heat Adhesion Toluene / methyl ethyl ketone = 50 /
After dissolving in 50 solvents so as to have a solid concentration of 30%,
It was applied on a biaxially stretched PET film (manufactured by Toyobo Co., Ltd., E5100), and a coated layer having a thickness of 100 μm after drying was provided.
Next, the untreated side of the PET film is overlaid on the coated side,
Heat sealing was performed at 140 ° C. for 30 seconds at 10 kg / cm ² . Then, the adhesiveness of what was cut out to a width of 2 cm was measured by a tensile tester.

EXAMPLE 1 Terephthalic acid was added to a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser.
Parts, 498 parts of isophthalic acid, 550 parts of ethylene glycol,
456 parts of neopentyl glycol, 302 parts of 3-phenoxy-1,2-propanediol and 0.5 part of tetra-n-butyl titanate were charged, and an esterification reaction was carried out at 180 ° C. to 250 ° C. for 4 hours. Then, the temperature of the reaction system was gradually reduced while the temperature was raised to 280 ° C., and then the pressure was reduced to 1 under a reduced pressure of 0.2 mmHg.
The reaction was carried out for 30 minutes to obtain a polyester resin (A-1). The obtained polyester resin was pale yellow and transparent. Table 1 shows the properties of the obtained resin.

Example 2 A polyester resin (A-2) was obtained in the same manner as in Example 1 except for the polymerization charge composition. Table 1 shows the properties of the obtained resin.

Example 3 Terephthalic acid was added to a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser.
Parts, 498 parts of isophthalic acid, 550 parts of ethylene glycol,
180 parts were charged with 456 parts of neopentyl glycol, 300 parts of compound 1 (a compound obtained by reacting aniline and glycidol), and 0.5 part of tetra-n-butyl titanate.
The esterification reaction was carried out for 4 hours at a temperature of from 250C to 250C. Next, the temperature of the reaction system was gradually reduced while the temperature was raised to 280 ° C., and the reaction was carried out under a reduced pressure of 0.2 mmHg for 1 hour and 30 minutes to obtain a polyester resin (A-3). The obtained polyester resin was pale yellow and transparent. Table 1 shows the properties of the obtained resin.

Example 4 Terephthalic acid 498 was added to a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser.
Parts, 498 parts of isophthalic acid, 550 parts of ethylene glycol,
456 parts of neopentyl glycol, 300 parts of compound 2 (reaction product of cyclohexanecarboxylic acid and glycidol)
And 0.5 parts of tetra-n-butyl titanate, 1
The esterification reaction was carried out from 80 ° C to 250 ° C over 4 hours. Then, the temperature of the reaction system was gradually reduced while the temperature was raised to 280 ° C., and the reaction was carried out under a reduced pressure of 0.2 mmHg for 1 hour and 30 minutes to obtain a polyester resin (A-4). The obtained polyester resin was pale yellow and transparent. Table 1 shows the properties of the obtained resin.

EXAMPLE 5 Terephthalic acid was added to a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser.
Parts, 498 parts of isophthalic acid, 200 parts of dioxane, 270 parts of phenylglycidyl ether and 20 parts of triethylamine, and after reacting at 100 ° C. for 3 hours, 550 parts of ethylene glycol, 456 parts of neopentyl glycol, hydrogenated dimer diol 4 Part and tetra-n-butyl titanate 0.
Five parts were charged, and the esterification reaction was carried out over 4 hours from 180 ° C to 250 ° C. Then, while raising the temperature to 280 ° C,
The pressure in the reaction system was gradually reduced, and then the pressure was reduced to 0.2 mmHg for 1 hour.
The mixture was reacted for 30 minutes to obtain a polyester resin (A-5). The obtained polyester resin was pale yellow and transparent. Table 1 shows the properties of the obtained resin.

Comparative Example 1 Terephthalic acid was added to a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser.
Part, 498 parts of isophthalic acid, 547 parts of ethylene glycol,
456 parts of neopentyl glycol and 0.5 part of tetra-n-butyl titanate were charged, and an esterification reaction was carried out from 180 ° C to 250 ° C for 4 hours. Then, the temperature of the reaction system was gradually reduced while the temperature was raised to 280 ° C., and the reaction was carried out under a reduced pressure of 0.2 mmHg for 1 hour and 30 minutes to obtain a polyester resin (B-1). The obtained polyester resin was pale yellow and transparent.

Comparative Example 2 A polyester resin (B-2) was obtained in the same manner as in Example 1 except for the composition charged for polymerization. Table 1 shows the properties of the obtained resin.

Comparative Example 3 Terephthalic acid was added to a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser.
Parts, 498 parts of isophthalic acid, 200 parts of dioxane, 387 parts of glycidyl phthalimide, and 20 parts of triethylamine. After reacting at 100 ° C. for 3 hours, 550 parts of ethylene glycol, 456 parts of neopentyl glycol, and
-n-Butyl titanate 0.5 parts, 180 ℃ ~ 250 ℃
The esterification reaction was carried out over 4 hours until the esterification reaction. Then 2
While gradually raising the temperature to 80 ° C, the pressure of the reaction system was gradually reduced to 0.1.
The reaction was carried out under a reduced pressure of 2 mmHg for 1 hour and 30 minutes to obtain a polyester resin (B-3). The obtained polyester resin was pale yellow and transparent. Table 1 shows the properties of the obtained resin.

[0037]

[Table 1]

[0038]

As described above, the polyester resin of the present invention has a lower melt viscosity than the polyester resin containing no side chain, and has excellent adhesion even under thermocompression bonding under the same conditions. From these points, it is extremely useful as a thermo-adhesive resin corresponding to environmental problems.

Claims (1)

[Claims] (1) A heat-adhesive polyester resin satisfying the following requirements: (1) All the carboxylic acid components contain at least 50 mol% of an aromatic dicarboxylic acid. (2) Weight average molecular weight of 5,000 to 200,000. The compound represented by a) is contained in an amount of 10 to 60 mol% when the total amount of all carboxylic acid components and all glycol components is 100 mol%. (A) XYZ X: a functional group containing carbon, and when Z is a hydrogen atom (H), the molecular weight is 50 or more, and the melting point is 100 ° C.
It represents the residue of the following compound. Y: O, S, NR (R represents a hydrogen atom or any monovalent group). Z: any one of a hydroxyl group, a carboxyl group, etc.
Represents a residue containing at least one