JPH0297519A - Highly crystalline polyester copolymer - Google Patents

Abstract

PURPOSE:To improve mechanical strengths, thermal properties, resistance to chemicals and moldability by reacting a dicarboxylic acid (derivative) mainly comprising terephthalic acid, a low-MW glycol mainly comprising ethylene glycol and a specific polymer. CONSTITUTION:beta-Methyl-delta-valerolactone is polymerized through ring opening in the presence of an initiator (e.g., ethylene glycol) and a catalyst to give a polymer. A dicarboxylic acid (derivative) component contg. at least 90mole% terephthalic acid and a low-MW glycol component contg. at least 90mole% ethylene glycol are esterified or transesterified. The product is mixed with 0.1-5wt.% beta-methyl-delta-valerolactone and/or its polymer obtd. as above, and polycondensed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a highly crystalline polyester copolymer having excellent mechanical properties, thermal properties, chemical resistance and moldability.

[Prior art and problems to be solved by the present invention] Polyethylene terephthalate has excellent heat resistance, mechanical strength, chemical resistance, etc., so it is used in a wide range of fields such as fibers, films, and molded products such as beverage bottles. It is used in However, the excellent properties of these molded products depend heavily on the crystallinity of polyethylene terephthalate, and the crystallization rate of polyethylene terephthalate is quite slow compared to other crystalline polymers such as nylon and polyacetal. Polyethylene terephthalate cannot be molded under molding conditions suitable for practical use, specifically mold temperatures of 70°C or higher and molding cycles as short as 30 seconds.In other words, the mold temperature cannot be set to a high temperature. When molded at a lower mold temperature, the resulting molded product lacks mechanical strength when taken out of the mold, resulting in poor dimensional stability.On the other hand, when molded at a lower mold temperature, although the moldability is good, the resulting molded product Due to the insufficient crystallinity of the resin constituting the polyethylene terephthalate, it is not possible to produce a molded article that exhibits the excellent properties inherent to the aforementioned polyethylene terephthalate.

Therefore, various methods have been proposed to improve the crystallization rate of polyethylene terephthalate. These methods can be broadly classified into the following two methods. One of them is that in the process of crystallizing polyethylene terephthalate from its molten state in the process of melt molding, the supercooling state is long, so in order to shorten this period, polyethylene terephthalate is Inorganic additives such as talc, silica, kaolin, and alumina to terephthalate (Japanese Patent Publication No. 46-38707, Japanese Patent Publication No. 47-271)
No. 42, etc.), copolymers of α-olefin and unsaturated carboxylic acid salts (Japanese Patent Publication No. 45-26225, etc.)
Alternatively, organic carboxylates such as sodium benzoate (
Japanese Patent Publication No. 46-29977, Japanese Patent Publication No. 54-1584
52, etc.).

Another method aims to improve the mobility of polyethylene terephthalate polymer chains at temperatures lower than the crystallization temperature. This is a method of adding a homopolymer or a block copolymer (Japanese Patent Publication No. 57-87543, Japanese Patent Publication No. 57-145145, Japanese Patent Publication No. 57-179239)
(Japanese Patent Application Laid-Open No. 58-21097, etc.).

Among these methods, the details of the mechanism of action of additives that promote the generation of crystal nuclei in polyethylene terephthalate are not known in many cases, but in those methods in which basic compounds such as carboxylic acid salts are added as nucleating agents, It is said that this effect is achieved by lowering the molecular weight of polyethylene terephthalate, so molded products obtained by adding such additives will inevitably have disadvantages in terms of physical properties. Also, polyalkylene sebacate,
In resin systems containing polyalkylene adipate, etc., these additives can be expected to have a plasticizer effect that helps the mobility of the polymer chains of polyethylene terephthalate at low temperatures, but they do not cause the crystallization of polyethylene terephthalate at high temperatures. Since these resins have little effect on the generation of crystal nuclei during chemical reaction, they must be used in combination with a so-called nucleating agent.

Furthermore, when the above additives are added to polyethylene terephthalate, there are problems such as coloring and gas generation during molding, and the molding temperature and amount of the mixture are restricted.

[Means for Solving the Problems] In view of the current situation, the present inventors have conducted intensive research and found that β-methyl-δ-valerolactone and/or a polymer obtained by ring-opening polymerization thereof is added to polyethylene terephthalate. The present invention was achieved by discovering that a polyester copolymer having high crystallinity suitable for molding can be obtained by copolymerizing a specific amount.

That is, the present invention uses a component (A) of a dicarboxylic acid or its derivative mainly composed of terephthalic acid, a component (B) of a low molecular weight glycol mainly composed of ethylene glycol, and a component (B) of a dicarboxylic acid or its derivative mainly composed of terephthalic acid.
- A polyester copolymer obtained by reacting component (C) with valerolactone and/or a polymer obtained by ring-opening polymerization thereof, wherein component (C) is 0.1% by weight type 5 in the copolymer. % of a highly crystalline polyester copolymer. Dicarboxylic acid or derivative thereof (A
) is preferably composed of at least 90 mol% of terephthalic acid or a derivative thereof.

The derivatives include dialkyl esters of terephthalic acid,
Examples include diaryl esters. Examples of dicarboxylic acids that can be used in combination as a dicarboxylic acid component in an amount of 10 mol% or less include phthalic acid, isophthalic acid, adipic acid, sebacic acid, naphthalene-1,4- or -2
, 6-dicarboxylic acid, diphenyl ether-4,4-dicarboxylic acid, and the like.

The low molecular weight glycol component (B) used in the present invention preferably comprises at least 90 mol% of ethylene glycol. Other glycol components include propylene glycol, butylene glycol, neopentyl glycol, cyclohexane dimetatool, 2,2-bis(4-
Examples include glycol components such as (hydroxyphenyl)propane, and these glycols are preferably used in combination with ethylene glycol in a proportion of 10 mol% or less.

As other components used in obtaining the polyester of Ikemizu's invention, oxyacids such as p-hydroxybenzoic acid and p-hydroxyethoxybenzoic acid can also be used in combination.

The polymer obtained by ring-opening polymerization of β-methyl-δ-valerolactone used in the present invention is a polymer obtained by ring-opening polymerization of β-methyl-δ-valerolactone. This is a polymer obtained by ring-opening polymerization with the addition of an agent and a conventionally known catalyst.

For example, if the initiator is ethylene glycol, it will be a polymer represented by the following structural formula.

C1h (m, n are integers) (I) Although m and n in the formula are not particularly defined,
Preferably, each number is in the range of 1 to 50.

The content of β-methyl-δ-valerolactone and/or the polymer (C) component obtained by ring-opening polymerization thereof is required to be 0.1 to 5% by weight in the polyester copolymer of the present invention. When the amount of component (C) is less than 0.1% by weight, the crystallization promoting effect of the polyester is not remarkable, and when the amount exceeds 5% by weight, the crystallinity of the polyester decreases (not only does the polyester This is not preferable because the mechanical strength of the molded product at high temperatures also decreases.The main chain of the molecule of the polyester of the present invention contains β-methyl-δ-valerolactone and/or a polymer structure obtained by ring-opening polymerization thereof. It is thought that this becomes a nucleus and crystallization begins.Therefore, polyesters with too many β-methyl-δ-valerolactone structures lose their molecular chain regularity, resulting in a decrease in crystallinity. However, it is considered that polyesters with too small a molecular structure do not exhibit high crystallinity because the number of crystallization nuclei decreases.

As a specific example of producing the polyester copolymer of the present invention, for example, from the time when the esterification reaction or the transesterification reaction is substantially started using the above-mentioned components (A) and (B), the polycondensation reaction can be carried out. Until the reaction is completed, β-methyl-δ-valerolactone and/or a polymer obtained by ring-opening polymerization thereof is added, and a polycondensation reaction is performed by a known method to obtain a polyester copolymer having a predetermined degree of polymerization. Although the method for obtaining the polymer can be mentioned, it is preferable to add the β-methyl-δ-valerolactone structure-containing compound at the initial stage of the polycondensation reaction. The form of addition of β-methyl-δ-valerolactone and/or the polymer obtained by its ring-opening polymerization is not particularly specified, and the addition may be in a powder state or a molten state. The condensation of polyester is preferably carried out using a metal compound such as antimony, germanium, titanium, tungsten or the like as a catalyst at 260°C to 300°C with stirring under vacuum. Further, in order to prevent coloring and decomposition of the resulting polyester, an appropriate stabilizer may be used in conjunction with the condensation.

In order to further enhance the crystallinity of a molded product obtained from the polyester of the present invention, it is preferable to blend an appropriate nucleating agent and/or crystallization accelerator.

Examples of nucleating agents and crystallization promoters include metal salts of Group 1a or Group 11a of the periodic table of organic carboxylic acids, benzoic acid esters or esters of benzoic acid derivatives, fatty acid esters, and metals of ionic copolymers. Examples include salts, inorganic particles, polyoxyethylene derivatives, epoxy compounds, sorbitan derivatives, etc., and specific examples include suium laurate, potassium laurate, sodium myristate, potassium myristate, calcium myristate, and stearic acid. Sodium, potassium stearate, calcium stearate, sodium octacosanoate, calcium octacosanoate, sodium benzoate, potassium benzoate, calcium benzoate, lithium terephthalate, sodium terephthalate, potassium terephthalate, ethylene glycol monobenzoate, ethylene glycol dibenzoate ,
Brobylene glycol monobenzoate, propylene glycol dibenzoate, neopentyl glycol monobenzoate, diethylene glycol dibenzoate,
Examples include triethylene glycol dibenzoate, ethylene glycol propylene glycol dibenzoate, ethylene-sodium acrylate copolymer, ethylene-sodium methacrylate copolymer, talc, titanium oxide, zinc oxide, and the like.

Depending on the purpose, the polyester copolymer of the present invention may contain fibrous fillers such as glass fiber, alumina fiber, carbon fiber, silicon carbide fiber, ceramic fiber, asbestos fiber 1fI and metal fiber, talc, kaolin, mica, clay, etc. Silicates such as wollastenite, sericite, bentonite, asbestos, alumina silicate, alumina,
Metal oxides such as silicon oxide, magnesium oxide, zirconium oxide, titanium oxide, calcium carbonate, magnesium carbonate, carbonates such as dolomite, sulfates such as calcium sulfate, barium sulfate, glass beads, boron nitride,
Particulate fillers such as silicon carbide, lubricants and mold release agents such as silica and stearate, ultraviolet absorbers, colorants containing pigments such as carbon black, flame retardants such as halogen compounds and phosphorus compounds, and flame retardant additives. Known additives such as additives, antioxidants, antistatic agents, and heat stabilizers may optionally be added. In addition, a small amount of other thermoplastic resins (for example, polyethylene, polypropylene, olefin resins such as ethylene copolymers, acrylic resins, fluororesins, polyamides, polyacetals, polycarbonates, polysulfones, polyphenylene oxides, polyester elastomers A
Graft copolymers such as BS resin and MBS resin) and thermosetting resins (for example, phenol resins, melamine resins, polyester resins, silicone resins, epoxy resins, etc.) can be blended. Moreover, since the polyester copolymer of the present invention can be made into a highly crystalline molded article, it can be applied to all fields requiring heat resistance, impact resistance, mechanical strength, chemical resistance, etc. The polyester of the present invention can be easily made into a molded body by a molding method such as injection molding or extrusion molding, or can be made into a film by obtaining fibers by known spinning and processing techniques, or by tenter method or inflation method. The molding method is not particularly limited. Products obtained by these molding methods all exhibit excellent properties derived from high crystallinity.

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples. In addition,
The molding and evaluation of the test pieces in the examples were carried out in the following manner.

(1) Molding of test piece The resin composition to be evaluated was heated under vacuum to 140"C and dried for 8 hours. Next, this was put into the hopper of a 45 mmφ screw injection molding machine, and the cylinder temperature was The mixture was melt-kneaded at 260'C=280''C and molded into 8 ounce ASTMI dumbbells and 1/4 inch wide Izot specimens using a mold set at 80°C. The molding cycle at this time was 30 seconds.

(2) Evaluation of crystallization rate The crystallization rate was measured using a differential calorimeter using a sample that had been previously dried at 140°C for 8 hours, melted, and rapidly cooled, and heated at a heating rate of 10°C in a nitrogen stream. /min, 280℃
The temperature was held for 3 minutes and the temperature was lowered at a rate of 10°C/min, and the crystallization temperature Tc'' during heating, the crystallization temperature Tc- during cooling, and the melting point T□ were measured. The higher the Tffip, the better the heat resistance. The larger the value of (Tc--Tc"), the higher the crystallization rate.

(3) Evaluation of mechanical strength Regarding the dumbbell test piece obtained by the method of (1), ASTM
A tensile test was conducted according to D-638. Similarly, the Izot impact strength of the Izot test piece was measured according to ASTM D-256.

(4) Evaluation of heat resistance The heat distortion temperature (HDT) of the ASTM I dumbbell was measured according to ASTM D-648, and was used as an index of heat resistance.

(5) Evaluation of moldability and molded product surface The ASTMI dumbbell was visually judged.

[Moldability] ×-11 Due to poor mold release, poor shape retention, etc., 30
Molding is very difficult in the second cycle.

Δ----Test molding is possible, but not practically suitable for production.

〇---Good molding work is possible.

[Surface of molded product] ×-m-No gloss on the surface (sink marks, flow marks, avatars, etc. are present).

△---There are no sink marks, flow marks, avatars, etc., but the surface is not glossy.

○---There are no defects on the surface and the surface has a good gloss.

Examples 1 to 5 and Comparative Examples 1 to 5 100 parts by weight of ethylene glycol and 200 parts by weight of terephthalic acid
Charge part by weight into a reaction vessel, pressurize the inside of the vessel, and bring the temperature inside the vessel to 24.
The esterification reaction was carried out at 0°C. No water outflow (
When the temperature at the top of the water outflow distillation column begins to rise,
β-Methyl-δ-valerolactone or its polymer (initiator: ethylene glycol, average molecular weight: 2000) was added in the amount shown in the table. Next, as a polymerization catalyst, 5b
203 was added at 500 ppm to the product in the kettle, and while the temperature in the kettle was raised to 280° C., the pressure inside the kettle was reduced to perform a polycondensation reaction. In this way, the intrinsic viscosity [η] (2
After increasing the degree of polymerization to 0.85 (measured at 5° C.), the polymer was taken out of the pot. Furthermore, the obtained polyester copolymer was decomposed with hydrazine, and the copolymerized amount of β-methyl-δ-valerolactone and its polymer was determined by gas chromatography. These copolymers were molded and evaluated using the method described above. The results are shown in the table.

As shown in the table (Examples 1 to 5 which are polyesters of the present invention)
is Comparative Example 1 (i.e., PE containing no copolymer components)
Compared to the polyester of T), it is extremely large (Tc--
Tc”) value.

This shows that the polyester copolymer of the present invention exhibits very good crystallinity, and it can be injection molded better than conventionally developed polyesters, making it possible to efficiently produce molded products with good surface gloss. It can be seen that it can be produced well.

On the other hand, polyesters outside the composition range of the present invention (i.e., Comparative Examples 2 to 5) do show improvement in mechanical strength, particularly impact resistance, but the (Tc--Tc") value is not sufficiently large. (Therefore, the moldability and surface condition of the resulting molded product are poor, and the heat resistance is also insufficient.

[Effects of the Invention] Since the polyester copolymer obtained by the present invention exhibits unprecedented high crystallinity, the field of application of this resin has been expanded, and especially in the molding field, it has improved moldability and mechanical properties of molded products. significantly improve.

Patent applicant: Mitsubishi Rayon Co., Ltd. Agent: Patent Attorney Toshio Yoshizawa Display of incidents Patent Application No. 1986-249686 name of invention Highly crystalline polyester copolymer person who makes corrections Relationship to the incident Patent applicant 2-3-19 Kyobashi, Chuo-ku, Tokyo (603) Mitsubishi Rayon Co., Ltd. President Yatabe Nagai

Claims (1)

[Claims] Dicarboxylic acids, mainly terephthalic acid, or derivatives thereof (
A polyester copolyester obtained by reacting component A, a low molecular weight glycol mainly composed of ethylene glycol (B) component, β-methyl-δ-valerolactone and/or a polymer obtained by ring-opening polymerization thereof (C) component. A polymer,
A highly crystalline polyester copolymer containing component (C) in an amount of 0.1 to 5% by weight in the copolymer.