JPH0397725A - Production of polyester - Google Patents

Abstract

PURPOSE:To obtain a polymer having excellent heat-resistance, etc., by mixing an aliphatic dicarboxylic acid, a diol and a liquid crystal dihydroxy compound. melting exclusively the aliphatic components to effect the reaction and finally melting the whole components to complete the reaction. CONSTITUTION:The objective polymer can be produced by compounding (A) an aliphatic dicarboxylic acid lower ester of formula I (n is 0-10), (B) an aliphatic diol (e.g. ethylene glycol) and (C) preferably 0.1-30mol% of a dihydroxy compound exhibiting liquid crystal nature and expressed by formula II (R<1> and R<2> are alkylene; p is 3 or 4; q and r are 0 or integer of >=1) such as 4,4''- dihydroxy-p-terphenyl, subjecting the system to ester-interchange reaction at a temperature to keep the component C from melting, raising the temperature to melt the component C, lowering the temperature to a level not to cause the precipitation of the component C and reacting the components.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing polyester, which has properties as a thermoplastic elastomer and is heat resistant. This invention relates to a method for stably producing polyester having excellent mechanical strength and formability in a short period of time.

(Prior Art) Generally, in order for a material to exhibit rubber elasticity, it is necessary that an amorphous polymer with easy molecular chain rotation be partially crosslinked. For example, in elastic rubber, sulfur molecules bridge molecular chains through chemical bonds, creating a network structure. In addition to rubber, materials that combine various polymer compounds and crosslinking agents have been proposed. These materials require a crosslinking process to be shaped into a certain shape, and after being chemically crosslinked, they do not exhibit thermoplastic properties. Crosslinked materials cannot be shaped by injection molding or extrusion.

In recent years, thermoplastic elastomers have been developed that exhibit rubber elasticity at room temperature and become plasticized at high temperatures. Various types of thermoplastic elastomers are manufactured and commercially available. This thermoplastic elastomer does not require the lengthy crosslinking process required for conventional rubber, and can be shaped by injection molding or extrusion. The molecular structure of thermoplastic elastomers is characterized by crosslinking that does not rely on strong chemical bonds, that is,
The typical structure of thermoplastic elastomers is a system that applies some kind of inter-polymer restraint that is effective only at room temperature, and is a polymer aggregate consisting of soft segments and hard segments. The chemical structures of soft segments and hard segments are different from each other, and in a hybrid composition of the two, homogeneous parts aggregate, and heterogeneous parts form a micro-disequilibrium structure that is phase-separated from each other.
At this time, the agglomerated portions of the hard segments exhibit a restraining effect between the molecules.

Examples of thermoplastic elastomers include styrene.
There are olefin-based, urethane-based, ester-based, amide-based, etc. In styrene-based materials, polystyrene forms a frozen phase as a hard segment, restraining molecular chains, and as a result exhibits rubber elasticity.

In olefin systems, the crystalline phase of polypropylene acts as a hard segment. In addition, in the 2-urethane system, polyurethane segments create physical crosslinks between molecular chains through hydrogen bonding. In addition, the ester type has polybutylene terephthalate chains, and the amide type has 6-nylon, 6.
Nylon chains such as 6-nylon act as hard segments.

(Problems to be Solved by the Invention) As described above, thermoplastic elastomers exhibit rubber elasticity at room temperature and are also malleable, so they are widely used in automobile parts and various industrial products. However, conventional thermoplastic elastomers have lower heat resistance than cross-linked rubbers because cross-linking is performed through physical restraint, which limits the softening and melting point of that part. In addition, the creep properties were also poor. For example, Toyobo's Perbrene S-9001, which is known as the ester type with the highest heat resistance among thermoplastic elastomers, has a melting point of 223°C and a heat distortion temperature (low load) of 146°C.
Even in the case of urethane-based materials, the softening point is at most 140°C.

A dihydroxy or monohydroxy compound having p-terphenyl or p-quarterphenyl skeleton e. Polyester, which is the key ingredient, has an extremely high transition point (melting point) from the crystalline state to the liquid crystalline state of this hydroxyl compound, which reflects its unique molecular structure, so it has the ability to form extremely strong and heat-resistant physical crosslinks. It is a thermoplastic elastomer with excellent heat resistance and mechanical properties. however. These hydroxy compounds are extremely difficult to dissolve in various solvents and other comonomers, so when using these hydroxy compounds to prepare polyester, the hydroxy compounds are melted at high temperatures, and then this compound and other comonomers are combined. It is necessary to carry out an ester reaction with the copolymerizable monomer. However, if the reaction is carried out for a long time at a temperature high enough to melt the hydroxyl compound, the product becomes colored and the physical properties of the raw material deteriorate. this is. This is thought to be due to the aliphatic fraction contained in the product being decomposed by the heat during the reaction. When a hydroxy compound and a copolymer monomer are polymerized at a low temperature to prevent thermal decomposition of biomaterials, the reaction of the dihydroxy compound is insufficient, so this hydroxyl compound may remain in the biomass. The resulting polyester had a low molecular weight and poor physical properties.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for obtaining polyester having a high molecular weight, excellent heat resistance and mechanical properties, and little coloring in a short time. There is a particular thing.

(Means for Solving the Problems) In the method for producing polyester of the present invention, the general formula is the following formula (1
) and an aliphatic dicarboxylic acid whose general formula is represented by the following formula (
In order to produce a polyester mainly composed of the dihydroxy compound represented by II) and an aliphatic diol, a lower ester of 3 dicarboxylic acid and an aliphatic diol are transesterified at a temperature at which the dihydroxy compound does not melt. Do. After the transesterification reaction is completed, the reaction temperature is raised to dissolve the dihydroxy compound,
Next, the temperature is lowered to a temperature within a range where the dihydroxy compound does not precipitate, and the transesterification reaction is further carried out at this temperature, thereby achieving the above object.

HOOC-(CH2)n-C,OOH (I
) (In the formula, n represents an integer from 0 to 10.) (In the formula, Hl
, R2 independently represents an alkylene group, p is 3 or 4, and q and r independently represent O or an integer of 1 or more. ) In the above aliphatic dicarboxylic acid. If a dicarboxylic acid having more than 10 carbon atoms is used, the physical properties of the molded article obtained from the aliphatic polyester will deteriorate. As the dicarboxylic acid, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adibic acid, suberic acid, and sebacic acid are preferably used.

Examples of the aliphatic diols include glycols and polyalkylene oxides. Examples of the above glycol include ethylene glycol, propylene glycol, and trimethylene glycol. 1.4-butanediol,
1.3-Butanediol. 1.5 pentanediol, 1
, 6-hexanediol, 1.7-heptanediol, 1,8-octanediol, 1.9-nonanediol, 1.10-decanediol. Cyclopenkun-1
．． 2-diol, cyclohexane-1,2 diol, cyclohexane-1,3-diol, cyclohexane-1
, 4-diol, cyclohexane-1,4 dimethanol, etc., and these may be used alone or in combination of two or more.

Examples of the polyalkylene oxide include polyethylene oxide, polybropylene oxide, polytetramethylene oxide, polyhexamethylene oxide, and the like. These may be used alone or in combination of two or more. When the number average molecular weight of the polyalkylene oxide becomes small, the ability to impart flexibility to the raw aliphatic polyester decreases, and when it becomes too large, the physical properties such as thermal stability of the obtained aliphatic polyester decrease. 100 to 20,000 is preferable. More preferably it is 500-5000.

The dihydroxy compound represented by the above formula [■] is a low molecular compound that exhibits liquid crystallinity, and the alkylene groups Rl and R2 are preferably ethylene or propylene groups, and q and r are 0.
or l is preferred, and 4.4"-dihydroxy-p-terphenyl represented by the following formula (A). 4.4111-dihydroxy-p-quarterphenyl represented by the following formula CB) and the following formula [C] 4.4'''di(2-hydroxyethoxy)-1ρ-quarterphenyl and the like are preferably used.

The transition temperature of 4,4'''-dihydroxy-p-terphenyl (A) from the crystalline state to the liquid crystalline state is 260°C; 4.
4+++-dihydroxy-p-quarterphenyl [B
] is 336°C, and that of 4.4'''-di(2-hydroxyethoxyLp-quarterphenyl [C] is 403°C.The liquid crystal state means that the compound is in a molten state, and the molecules refers to a state in which the dihydroxy compounds (II) maintain an oriented state.The above dihydroxy compounds (II) may be used alone or in combination.

Liquid crystal molecules generally have high crystallinity, and as mentioned above, 4
,41-dihydroxy-p-terphenyl [A], 47
+++-dihydroxy-p-quarterphenyl [B]
and 4,4゛"-di(2-hydroxyethoxyLp-quarterphenyl [C] have a high transition point from crystal to liquid crystal state, so these dihydroxy compounds [■]
When incorporated into a polymer chain, the polymer exhibits unique properties.

That is, dihydroxy compound (II) exhibits crystallinity,
Moreover, since its transition point is high, dihydroxy compounds [■
) Forms strong and highly heat-resistant physical crosslinks even when the amount is small. the result. It is presumed that a thermoplastic elastomer with high heat resistance can be obtained without impairing the flexibility derived from the soft segment.

Avoid adding polysilicone having two hydroxyl groups, lactone, or aromatic hydroxycarboxylic acid to the aliphatic polyester containing the above aliphatic dicarboxylic acid [I], aliphatic diol, and dihydroxy compound (II). It may be included as a component.

The above-mentioned polysilicone has two hydroxyl groups, and polysilicone with two hydroxyl groups at the molecular ends is preferable, for example. Dimethylborisiloxane has two hydroxyl groups at both ends of the molecule. diethylborisiloxane,
Examples include diphenylpolysiloxane. The number average molecular weight of polysilicone is. If it becomes small, the ability to impart flexibility to the polyester produced will decrease, and if it becomes large, it will be difficult to grow the polyester, so the ratio of 100 to 20
, 000 is preferred. More preferably 500 to 5,0
It is 00.

The lactones ring-open and react with acids and hydroxyl groups to add aliphatic chains, giving flexibility to polyesters, and those having 4 or more carbon atoms in the ring. Preferably, 5- to 8-membered rings are preferred, such as ε-cabrolactone, δ-valerolactone,
Examples include T-butyrolactone.

The above-mentioned aromatic hydroxycarboxylic acids impart rigidity and liquid crystallinity to polyester, and include salicylic acid and metahydroxybenzoic acid. Para-hydroxybenzoic acid, 3-chloro-4-hydroxybenzoic acid, 3-bromo-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3-methyl-4-hydroxybenzoic acid, 3-phenyl-4-hydroxy benzoic acid. 2-Hydroxy-6-naphthoic acid. Examples include 4-hydroxy-4-carboxybiphenyl, preferably. Rose hydroxybenzoic acid, 2-hydroxy-6 naphthoic acid, 4-hydroxy-4
It is monocarboxybiphenyl.

Furthermore, the above aliphatic polyester. In order to improve the mechanical properties of polyester, dihydroxy compounds (
Aromatic diols and aromatic dicarboxylic acids other than II) may be contained as constituent components.

Aromatic diols include hydroquinone, resorcinol,
Chlorohydroquinone, bromohydroquinone. Methylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4.4''-dihydroxybiphenyl, 4.4''-dihydroxydiphenyl ether, 4.4'-dihydroxydiphenyl sulfide, 4.4'-dihydroxydiphenyl sulfone, 4
．． 4'-dihydroxybenzophenone, 4.4'-dihydroxydiphenylmethane, bisphenol A, 1.
1-di(4-hydroxyphenyl)cyclohexane, 1
, 2-bis(4-hydroxyphenoxy)ethane.
(2), 4-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, etc.

Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, metal salts of 5-sulfoisophthalic acid, 4,4'-dicarboxybiphenyl, 4,4'-dicarboxydiphenyl ether, and 4,4'-dicarboxydiphenyl sulfide. , 4,4"-dicarboxydiphenylsulfone, 3.3"-dicarboxyhenzophenone, 4.
4'-dicarboxybenzophenone, 1,2bis (4
-carboxyphenoxy)ethane, 1.4 dicarboxynaphthalene. Or 2,6-dicarboxynaphthalene and the like.

In an aliphatic polyester consisting of a dihydroxy compound CI1), an aliphatic diol, and an aliphatic dicarboxylic acid, when the content of the dihydroxy compound (II) decreases, the heat resistance decreases, and when the content increases, the elastic modulus increases and the flexibility decreases. The content of the dihydroxy compound [■] is preferably 0.1 to 30 mol% of the total monomers constituting the polyester.
More preferably, it is 0.5 to 20 mol%, and still more preferably 1.0 to 10 mol%. In addition, when polyalkylene oxide or polysilicone is used as a non-aromatic diol, its structural unit is counted as one monomer. That is, polyethylene oxide with a degree of polymerization of 10 is counted as 10 monomers.

In the present invention, first, the lower ester of the dicarboxylic acid and the diol component are combined into a dihydroxy compound CI! ) is carried out at a temperature that does not melt the transesterification reaction. The lower ester is usually a lower alkyl ester, such as methyl ester, ethyl ester, propyl ester, etc. The reaction temperature here is dihydroxy compound [■]
may be varied as long as the temperature does not melt. Next, after the above transesterification reaction is completed. The reaction temperature is raised to a temperature at which the dihydroxy compound [■] melts. The temperature here is preferably as low as possible, as long as the dihydroxy compound CIN is dissolved. After the dihydroxy compound [■] is dissolved, the reaction temperature is lowered to a temperature at which the dihydroxy compound CII) does not precipitate. The temperature here is preferably particularly low as long as the dihydroxy compound (II) does not precipitate. The temperature at which the dihydroxy compound [■] begins to precipitate varies depending on the dihydroxy compound (n) used, the composition concentration, etc., but can be determined by actual measurement. A transesterification reaction between the dihydroxy compound and other copolymerizable monomers is carried out at a temperature within this range for a predetermined period of time, and then allowed to cool to obtain a polyester.

When polycondensing the dihydroxy compound and other copolymerizable monomers, catalysts generally used in producing polyesters may be used. These catalysts include lithium, sodium, potassium, cesium, magnesium, calcium, barium, strontium, zinc, aluminum, and titanium. cobalt. germanium, tin, lead,
Antimony. Arsenic. Cerium, boron, cadmium. Metals such as Masogan. Its organometallic compound, organic acid salt 7 metal alkoxide. Examples include metal oxides.

Particularly preferred catalysts are calcium acetate and stannous diacyl. Tetraacyl stannous. Dibutyltin oxide, dibutyltin dilaurate, dimethyltin malate. Tin dioctanoate, tin tetraacetate triisobutylaluminum, tetrabutyl titanate, germanium dioxide,
and antimony trioxide. Two or more of these catalysts may be used in combination. In addition, water is produced as a by-product during polymerization. Efficiently distills alcohol, glycol, etc. To obtain high molecular weight polymers. Add 1ml of the reaction system to the late stage of polymerization.
It is preferable to reduce the pressure to 1 g or less. The reaction temperature is generally 150-350°C.

The following additives may be added during or after the production of the polyester of the present invention within a range that does not impair practicality. Namely, glass fiber, carbon fiber, boron fiber. Silicon carbide fiber, alumina fiber. Amorphous fibers, inorganic fibers such as silicone, titanium, and carbon fibers, organic fibers such as aramid fibers, inorganic fillers such as calcium carbonate, titanium oxide, mica, and talc, triphanyl phosphite, trilauryl phosphite, and tris. nonylphenyl phosphite,
2-tert-butyl-α-(3-tert-butyl-4hydroxyphenyl Lp-cumenylbis(p-
heat stabilizers such as nonylphenyl) phosphite, flame retardants such as hexacyclododecane, tris(2,3-dichlorobutyr)phosphate pentapromophenyl allyl ether, p-terL-butylphenyl salicylate, 2- Hydroxy-4-methoxybenzophenone 72-Hydroxy-4-methoxy-2'-carboxybenzophenone, UV absorbers such as 2,4.5-1-lihydroxysibutyrophenone, butylhydroxyanisole, hetylhydroxytoluene, distearyl oxide Antioxidants such as dipropionate, dilauryl thiodipropionate, hindered phenolic antioxidants,
N,N-bis(hydroxyethyl)alkylamine,
Alkylaryl sulfonate Antistatic agents such as alkyl sulfanate, barium sulfate. Inorganic substances such as alumina and silicon oxide; higher fatty acid salts such as sodium stearate, barium stearate, and sodium palmitate;
benzyl alcohol. Examples include organic compounds such as benzophenone; crystallization accelerators such as highly crystallized polyethylene terephthalate and polytrans-cyclohexanedimethanol terephthalate.

Furthermore, the aliphatic polyester obtained by the production method of the present invention can be mixed with other thermoplastic resins such as polyolefin, modified polyolefin, polystyrene, polyamide, polycarbonate, polysulfone, polyester, etc.
Alternatively, it may be used by mixing it with a rubber component to modify its properties.

The aliphatic polyester obtained by the production method of the present invention is made into a shaped body by press molding, extrusion molding, injection molding, blow molding, or the like. What are the physical properties of the precept form? It can be arbitrarily changed depending on its constituent components and their blending ratio. When polyester is prepared as a thermoplastic elastomer. The cylindrical body is suitably used for flexible cylindrical bodies such as automobile parts, hoses, belts, and packing, as well as paints, adhesives, and the like.

(Example) less than. The present invention will be explained based on examples.

In a glass flask with an internal volume of 100 1 d, equipped with a Mitsuarashi Kaido stirrer, a thermometer, a gas inlet, and a distillation port. Dimethyl adibate (hereinafter referred to as DMA) 34.84g (200
mmol), ethylene glycol (hereinafter referred to as EG)
29.79 g (480 mmol), 4.4”
'-dihydroxy-p-quarterphanyl (DI
) 6.7682 g (20 mmol
), and germanium dioxide O. as a catalyst. '00
After adding 72 g and 0.044 g of calcium acetate and purging the inside of the flask with nitrogen, the flask was immersed in an oil bath, the bath temperature was immediately raised to 190°C, and the reaction was carried out for about 2 hours. As the reaction progressed, methanol began to distill out from the flask, and bis(2-hydroxyethyl) adipate (hereinafter referred to as BHEA) was produced. During this reaction,
DIIQ was hardly dissolved. Next, the bath temperature was raised to 320°C and stirring was continued. During this time, DHQ was dissolved in liquid BHEA. After confirming that the DHro had dissolved, the bath temperature was immediately lowered to 300'C. It took 30 minutes until DHQ was dissolved and the temperature was lowered. After continuing the reaction for 1 hour at a bath temperature of 300"C, the distillation port was connected to a vacuum vessel and the inside of the flask was adjusted to 1mmHg.
The polycondensation reaction was carried out for about 2 hours under reduced pressure as shown below.

During the reaction, ethylene glycol was distilled out, and an extremely viscous liquid was formed in the flask. After the flask was allowed to cool, the flask was broken and the product was taken out. The color of the obtained aliphatic polyester was visually observed and the intrinsic viscosity was measured. Intrinsic viscosity [η] in orthochlorphenol,
Measurements were taken at 30°C. The raw bottom material was a very pale yellow translucent solid with an intrinsic viscosity of 1.45.

For comparison, the same heptanomer and catalyst as in Example 1 were placed in a flask similar to that in Example 1, and the mixture was heated in an oil bath at 190°C for about 2 hours.
Perform a time reaction. BHEA was grown in the same manner as in Example 1. Next, the bath temperature was raised to 320'C, stirred, and D}! Q was dissolved in BHEA in liquid state. D.H.
After confirming the dissolution of Q, the reaction was continued for about 1 hour while maintaining the temperature at 320°C, and then the polycondensation reaction was carried out for about 2 hours while the pressure inside the flask was reduced to .lmmHg or less. During the reaction, ethylene glycol was distilled out, and an extremely viscous liquid was formed in the flask. After the flask was left to cool, the glass was broken and the raw material was taken out. The bioactive substance is a translucent solid colored brown, and its intrinsic viscosity is 1.30.
Met.

In a flask similar to Example 1, add the same monomer as Example 1. A catalyst was charged and the reaction was carried out in an oil bath at 190°C for about 2 hours, and then the bath temperature was raised to 300°C and stirred to dissolve DHQ in liquid BllEA.DHQ was completely dissolved. It took about 1 hour to dissolve. After continuing the reaction for about 1 hour at a bath temperature of 300°C, the polycondensation reaction was carried out for 2 hours while the pressure inside the flask was reduced to 1 ma + Hg or less. Along with the reaction, ethylene glycol was distilled out. , an extremely viscous liquid was formed in the flask. After the flask was left to cool, the glass was broken and the raw material was taken out. The raw material was an extremely pale yellow, translucent solid; The viscosity was 1.40.

From the above results, we found the following.

When the temperature was lowered after dissolving DHQ and the transesterification reaction was further performed (Example 1), when the temperature at which DIIQ was dissolved (320'C) was maintained and the transesterification reaction was continued (Comparative Example 1) In comparison, it has less coloring and higher intrinsic viscosity. In addition, when the melting temperature is low (Comparative Example 2), D
It takes time for HQ to completely dissolve, and its intrinsic viscosity is low.

(Effects of the Invention) According to the present invention, a dihydroxy compound with high crystallinity and a high melting point can be introduced into the molecular chain without keeping the reaction system at high temperature for a long time. Polyester with excellent physical properties and extremely little coloring can be obtained in a short time.

The polyester obtained in this way. It has the performance as a thermoplastic elastomer and is also heat resistant. Mechanical properties,

Claims (1)

[Claims] 1. Main constituents are an aliphatic dicarboxylic acid whose general formula is represented by the following formula [I], a dihydroxy compound whose general formula is represented by the following formula [II], and an aliphatic diol. In producing polyester, a lower ester of dicarboxylic acid and an aliphatic diol are transesterified at a temperature at which the dihydroxy compound does not melt, and after the transesterification reaction is completed, the reaction temperature is raised to convert the dihydroxy compound into A method for producing polyester, which comprises dissolving the polyester, then lowering the temperature to a temperature within a range at which a dihydroxy compound does not precipitate, and further carrying out a transesterification reaction at this temperature. HOOC-(CH_2)n-COOH[I] (in the formula,
n represents an integer of 0 to 10. ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [II] (In the formula, R^1 and R^2 independently represent an alkylene group, p is 3 or 4, and q and r are independently 0 or 1
Indicates an integer greater than or equal to )