JPS6031525A - Production of high-viscosity polyester block copolymer - Google Patents

Abstract

PURPOSE:To form the titled copolymer having excellent heat resistance and light resistance, a high m.p. and a high melt viscosity and being easily used in not only injection molding but also extrusion molding, by polymerizing a specified polyester block copolymer in a solid phase. CONSTITUTION:A crystalline aromatic polyester (e.g., hydroxyl group-terminated polyethylene terephthalate of an MW >= about 5,000) is copolymerized with a lactone (e.g., epsilon-caprolactone) at a temperature (>= about 270 deg.C) higher than the m.p. of the formed copolymer. The resulting polyester block copolymer (lactone content of about 5-95wt%) is further polycondensed in a solid phase in a high vacuum at about 100-200 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a high viscosity polyester block copolymer.

A polyester type block copolymer with rubber-like elasticity obtained by reacting a crystalline aromatic polyester with lactones has excellent rubber-like elastic properties, and has been used in various ways due to its excellent light resistance, heat resistance, etc. It is a material that has recently become of interest in its uses. Methods for reacting aromatic polyester and lactone include a method for reacting crystalline aromatic polyester and lactone (Japanese Patent Publication No. 48-4116), a method for reacting crystalline aromatic polyester and lactone, and a block initial polymer obtained by reacting the crystalline aromatic polyester and lactone. A method is known in which a polyfunctional acylating agent is reacted with a polyfunctional acylating agent to effect chain extension (Japanese Patent Publication No. 48-4115). However, there are limits to its use due to the low viscosity and low strength of the resulting polymer. For example, in applications such as injection molding, the viscosity is low, causing a lot of flaking.
Good molded products are difficult to obtain.

On the other hand, as a method for obtaining a high viscosity polyester polymer, a method in which the polycondensation reaction is continued for a long period of time in a molten state at a high temperature under a high vacuum has long been known. In this method, the viscosity is improved, but the melting point is significantly lowered.

The present inventors have conducted intensive research to improve the viscosity of a polyester pulck copolymer obtained by reacting an aromatic polyester with a lactone, and as a result, the present invention has been achieved.

This is a method for producing a high-viscosity polyester copolymer, which is characterized in that the copolymers are polymerized in the same phase.

The polymer of the present invention has excellent heat resistance, light resistance, and high melting point, and also has high melt viscosity and high strength, so it can be easily used not only for single injection molding but also for single extrusion molding. This greatly expands the uses of block copolymers. The high viscosity polyester copolymer of the present invention also has superior tear strength compared to ordinary polyester block copolymers.

The polyester block copolymer in the present invention is obtained by reacting a crystalline aromatic polyester and lactones. Crystalline aromatic polyester is a polymer that mainly contains ester bonds or ester bonds and ether blue gold, has at least one type of aromatic group as the main repeating unit, and has a hydroxyl group at the end of the molecule, and is used as a molding material. The molecular weight is preferably one having a molecular weight of a o o o or more. In addition, as adhesive 1 coating material, molecule 'N, 5
A polyester having a molecular weight of 00 or less may be used.

Preferred specific examples include 1 polyethylene tere 7 tallate - polytetramethylene tere 7 tallate 1 poly-1,4-
Homopolyesters such as cyclohexylene dimethylene terephthalate 1 polyethylene-2,6-naphthalate,
Polyester ethers such as polyethylene oxybenzoate (poly-p-phenylene bisoxyethoxy terephthalate) - consisting mainly of tetramethylene tereate units or ethylene terephthalate units, plus 1 tetramethylene or ethylene isophthalate unit - 1 tetramethylene or ethylene adipate unit These include copolymerized polyesters or copolymerized polyester ethers having copolymerized components such as methylene or ethylene sebacate units to 1,4-cyclohexylene dimethylene tele7thalerate units and tetramethylene or ethylene-p-oxybenzoate units. The content of methylene ethylene terephthalate-F units or ethylene terephthalate units is preferably 60 mol% or more.

As the lactone, ~ε-cacabractone is most preferable, and enantolactone to cabrylolactone are also used, but two or more types of lactones can also be used at the same time.

In order to obtain the polyester elastomer used in the present invention - the reaction between the crystalline polyester and the lactones may be carried out without a N catalyst, or even if a catalyst is used, the present invention will not be invalidated in any way. The content of lactone in the polyester block copolymer is 6 to 95% by weight, preferably 20 to 0% by weight.

The reaction temperature is usually 270° C. or lower, which is higher than the melting point of the copolyester. Of course, this will vary depending on the type of aromatic polyester and its composition ratio with lactone.

The present invention comprises a method of obtaining a high-viscosity polyester elastic body by roughly condensing and polymerizing the above-mentioned polyester elastic body in a solid phase state. It is necessary that the reaction temperature is such that the copolymerized polyester elastomer can always maintain a solid state. It is usually easy to mold at 220° C. to extrusion molding, and has higher viscosity and strength than the original polyester block copolymer, making it an excellent molded product.

The effects of the present invention will be explained in detail with reference to Examples below, but the present invention is not limited thereto.

In the Examples, each physical property was measured according to the following procedure.

(1) Tensile strength and elongation The chip was formed into a 2-inch thick flat plate using a heat press, and a dumbbell-shaped No. 3 test piece was punched out and stretched at a speed of 50 m/min to calculate the load (b) at which it broke. Initial cross-sectional area (cJI)
The value divided by is defined as strength (#/cal), and the ratio of the elongation of the sample until breakage to the original sample length was defined as elongation (%).

(2) Melting point: 20°C using a differential scanning calorimeter manufactured by Perkin-Elemer
The endothermic peak when the temperature was raised at a rate of 1/min was taken as the melting point.

(8) Reduced specific viscosity Measured under the following conditions Solvent: pheno-/I//tetrachlor! Ethane weight ratio 6
/4 Concentration; 50 Misaki/25gt Temperature; 30℃ Production example L Polyte) Ramethylene tele 7 tallate 70 phantom, ε-Cub p
Place lactone 30# in a reaction vessel ~ After nitrogen gas purification,
The melt reaction was carried out at 230° C. for 2 hours while stirring. Unreacted 6-caprolactone was then removed under vacuum for 30 minutes.

The resulting polyester elastomer had a reduced specific viscosity of 11.16. Further, the tensile strength at break was 315 #/Cds, and the tensile elongation at break was 743%.

Example L The polyester elastomer chips 5 and 9 obtained in Production Example 1 were placed in a rotary vacuum dryer (manufactured by Kusunoki Kikai Seisakusho) and heated at a predetermined temperature and under high vacuum (1 Torr or less) for a predetermined period of time. Made it react. The melting point and reduced specific viscosity of the obtained polyi-i were measured.

Comparative Example L The polyester elastomer chips obtained in Production Example 1 were placed in an autoclave under a high vacuum (1 Torr) of 230
After 10 minutes, the reaction system heated to a temperature of 0.degree. C. became a homogeneous molten state, and the melting reaction was continued at the same temperature for 1 to 6 hours, after which the melting point and viscosity of the polymer were measured.

Table 1 Example a The chips obtained in Example 1 and Comparative Example 1 were heated to 100°C for 1.
After vacuum drying for 6 hours, the 1-strength elongation was measured according to the 1-tensile strength and elongation measuring method. Tear strength was also measured.

Table 2 As is clear from Tables 1 and 2, the polyester block copolymer obtained according to the present invention (compared to that polymerized in a molten state) has excellent physical properties such as high melting point and high strength. shows.

Patent applicant: Toyobo Co., Ltd.

Claims (1)

[Claims] A patented method for producing high-viscosity polyester copolymers that involves polymerizing them in a solid phase.