JPS6029626B2 - polyester elastomer march tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyester elastomer tube that is highly flexible, has excellent long-term heat resistance, weather resistance, and flexibility at low temperatures, and has excellent moldability.

Traditionally, natural rubber and synthetic rubber have been used for various pressure hoses such as hydraulic hoses and water pressure hoses, vacuum hoses, and brake tubes used in the automobile industry, etc., and have particularly special functions such as high initial modulus at high temperatures and shock resistance at low temperatures. For applications that require strength, sacrificial properties, and long-term heat resistance and weather resistance, it is necessary to use multiple tubes or add various additives such as reinforcing materials and plasticizers to achieve certain functions, even if they are insufficient. The current situation is that we are trying to have them.

Moreover, since such vulcanizable rubber requires a vulcanization process, the manufacturing process is not only complicated, but also there are restrictions on shape and length, and it has been desired to improve not only physical properties but also moldability.

Recently, tube hoses made of polyamide (known as nylon 11 and 12) and polyurethane, which have excellent moldability and do not require vulcanization, have appeared, but the former have low rebound resilience and can be easily bent with a large radius. It has drawbacks such as bending and extremely poor low-temperature properties.

Further, although the latter has excellent flexibility itself, it has insufficient performance in terms of balance of water resistance, oil resistance, heat resistance, weather resistance, etc. Therefore, it has good moldability without the need for vulcanization, and has mechanical properties such as high modulus at high temperatures, excellent flexibility and bursting strength at low temperatures, oil resistance, water resistance, heat resistance, and stiffness resistance. It is hoped that tube hoses will be made from rubber materials. The present inventors focused on and studied polyester elastomer as a polymer material suitable for manufacturing tube hoses with such performance, and as a result, a polyester elastomer with a specific composition and a specific viscosity was found. It was discovered that this material had unprecedented performance and excellent moldability, and the present invention was thus developed.

That is, the present invention provides a dicarboxylic acid consisting of 80 to 60 mol% of terephthalic acid and 20 to 40 mol% of isophthalic acid or phthalic acid, or an ester-forming derivative thereof;
, 4-butanediol and a number average molecular weight of about 500 to
3000 poly(tetramethylene oxide) glycol or an ester-forming conductor thereof such that the proportion of poly(tetramethylene oxide) glycol units in the total polymer is 25 to 5% by weight, Relative viscosity (0.5% in orthochlorophenol) was determined so that the solution viscosity of the polymer satisfied the following formula.
Concentration, 2500) p: poly(tetramethylene oxide)
A tubular molded product of polyester elastomer is provided, which is characterized by comprising a polymer having glycol units with a weight distribution in the total polymer.

That is, the tube of the present invention is highly related to the structure of the polymer, and the dicarboxylic acid components used in the production of the polymer of the present invention are terephthalic acid and isophthalic acid or phthalic acid and their ester-forming derivatives; The molar ratio of isophthalic acid or phthalic acid is (80 to 60
): (20-40), more preferably (80-70):
(20-30). It is essential that the molar ratio of terephthalic acid and isophthalic acid or phthalic acid is within the above range, and that the glycol component forming the hard segment is 1,4-butanediol. The use of 1,4-butanediol as the glycol component is important for providing excellent moldability, crystallinity, and thermal properties to the copolymerized polyester, and also regarding polymerizability to provide a polymer with a high degree of polymerization. It is necessary that the diol component be 1,4-butanediol. In the present invention, it is essential to use a copolymerized acid component of isophthalic acid or phthalic acid for terephthalic acid, and when the molar ratio of terephthalic acid, noisophthalic acid, or phthalic acid is greater than 80/20, the object of the present invention can be achieved. The flexibility and high degree of elastic recovery required for an elastomer tube are not sufficient, and if it is less than 60/40, it is not practical in terms of thermal properties, and the tube formability and polymerization reactivity are also poor. Furthermore, poly(tetramethylene oxide) glycol is most suitable as the poly(alkylene oxide) glycol forming the basis of the soft segment component of the present invention in terms of heat resistance, chemical resistance, moldability, etc., and its number average molecular weight is 50
0-3000, preferably 600-2500.

If the number average molecular weight of poly(tetramethylene oxide) glycol is less than 500, the elastic recovery performance will not be sufficient, and if the molecular weight is too high, the phase separation structure will become too large and the mechanical properties of the elastomer tube will deteriorate. In addition, the tube formability decreases. The proportion of poly(tetramethylene) oxide glycol units in the total copolymer is from 25 to 5% by weight, particularly preferably from 35 to 5% by weight.
If the amount is too small, it will not be possible to achieve the desired elastomer tube with flexibility and excellent elastic recovery, and if it exceeds 5% by weight, the heat resistance will deteriorate. This provides only elastomers that have lost the significance of the present invention in terms of light resistance, moldability, and the like. The present invention provides hollow molded articles such as tubes made from a polyether ester copolymer obtained by copolymerizing terephthalic acid, isophthalic acid or phthalic acid, 1,4-butanediol, and poly(tetramethylene oxide) glycol in a specific range. It discloses that it has a uniquely high degree of elastic recovery, excellent mechanical properties, thermal properties, moldability, etc. in a well-balanced manner. When an acid or an aliphatic dicarboxylic acid such as adipic acid is used, moldability and elastic recovery properties are poor, and heat resistance is also reduced.

Furthermore, when other aliphatic diols such as ethylene glycol are used in place of 1,4-butanediol, only poor moldability is obtained due to low crystallinity. Thus terephthalic acid, isophthalic acid or phthalic acid, 1,
4-butanediol and poly(tetramethylene oxide) glycol are the main polymer ester components, and their use alone is preferred, but the acid component, low molecular weight glycol, and poly(alkylene oxide) glycol each have a weight of about 2 It is also possible to add other copolymerization components up to mol % to make a polymer suitable for the intended use of hollow bodies such as tubes.

As the third copolymerizable dicarboxylic acid component, 2,6
-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, diphenyl-P'P-dicarboxylic acid, bis(p
Aromatic dicarboxes such as -carboxyphenyl)methane, anthracene dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, ethylenebis-p-benzoic acid, 1,4-tetramethylenebis-P-benzoic acid, p-phenylene diacetic acid, etc. Mention may be made of aliphatic and cycloaliphatic dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, 1,4-cyclohexanedicarboxylic acid. Examples of the second diol that can be polymerized include ethylene glycol, 1,3-butasodiol, 1,2- and 1,3-propylene glycol, 1,
5-bentanediol neobentyl glycol, 1,6
-hexanediol, decamethylene glycol, diethylene glycol, 1,3- and 1,4-cyclohexanedimethanol, m- and p-dihydroxymethylbenzene, 2,2-di(p-hydroxyphenyl)propane, and the like. Poly(alkylene oxide) glycols that can be copolymerized as a minor component of 2% by weight or less include polyethylene glycol, polypropylene glycol, and block copolymers of ethylene oxide and propylene oxide. Furthermore, polyfunctional components such as polycarboxylic acids, polyols, and polyoxycarboxylic acids may be added depending on the case, and by adding such polyfunctional components, the melt viscosity of the polymer can be increased and the polymerization rate can be increased. is also possible.

The amount of the polyfunctional component that can be added is 5.0 mol % or less, preferably 3.0 mol % or less, based on the dicarboxylic acid and diol components forming the polymer. Those that can be used as polyfunctional components include trimellitic acid, trimesic acid, pyromellitic acid, 3,3',4,4'-penzophenonetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, and Examples include derivatives thereof such as acid esters and acid anhydrides, glycerin, bentaerythritol, and the like. In particular, by increasing the melt viscosity with such polyfunctional components, it is also possible to improve the shape retention during tube molding. A conventional method for producing a copolymerized polyester can be applied as is to a method for producing a polyether ester made of these components.

For example, dimethyl terephthalate and dimethyl isophthalate or dimethyl phthalate are mixed in excess molar number, that is, 1.05 to 2. 150-230 molar in the presence of 1,4-butanediol and a conventional esterification catalyst.
Transesterification is carried out by heating reaction under normal pressure at a temperature of 0.00 ml, distilling off methanol, and then adding poly(tetramethylene oxide) glycol, followed by heating polycondensation at 200 to 260 pm under reduced pressure of 3 Misakichog or less. let Poly(tetramethylene oxide) glycol may be added before the transesterification reaction. In addition to the method using dimethyl ester, it is also possible to directly polymerize dicarboxylic acids. First, terephthalic acid and isophthalic acid or phthalic acid (
anhydride) with 1,4-butanediol at normal pressure,
A polyether ester copolymer can also be obtained via a mixture of bis(hydroxybutyl) terephthalate and pis(hydroxybutyl) isophthalate or bis(hydroxybutyl) phthalate. It is also possible to prepare a copolymer of polybutylene terephthalate and polybutylene isophthalate or polybutylene terephthalate in advance, mix it with poly(alkylene oxide) glycol, and convert it into a polyether ester by transesterification.

Although a wide variety of catalysts can be used, particularly preferred results are obtained using organic titanates such as tetrabutyl titanate alone or in combination with magnesium, calcium or zinc acetates.

Also, Mg [HTi (OR
6)] A titanate body such as 2 is also one of the preferred catalysts. The use of such catalyst systems allows for polymers with high degrees of polymerization suitable for providing the polyester elastomer tubes of the present invention. Regarding the degree of polymerization of the block copolyether ester produced in this way, it is necessary that the solution viscosity of the polymer satisfies the following formula.

r: Relative viscosity (0.5% concentration in orthochlorophenol: 25 oo) p: Weight fraction of poly(tetramethylene oxide) glycol units in the total polymer The melt viscosity satisfies the above equation. If it is not satisfied, the mechanical properties and moldability of the polyester gel elastomer into tubes, etc. are not sufficient.

In other words, block copolyether ester has a relatively low crystallization and solidification rate, and is an extremely sticky polymer at high temperatures, so it does not adhere to the inner diameter of the tube and the sizing plate that determines the inner diameter during tube forming. It was easy for the hardened tube to sag, making it difficult to obtain a perfectly round tube with the desired diameter.

For this reason, elastomer tubes that have good moldability and have both physical properties, particularly flexibility and aging resistance, have not been known. For example, JP-A-48-29896
A block copolyether ester made from polybutylene terephthalate and a low content of poly(alkylene oxide) glycol, which is known in the above publication, has excellent moldability, but the flexibility is poor in terms of rubber elasticity. Only unsatisfactory things were known.

That is, tubes obtained from these polymers only had relatively large minimum bending radii. The present inventor copolymerized isophthalic acid or phthalic acid with block copolyether ester in a specific ratio to significantly improve flexibility and rubber elasticity, and at the same time, increase the degree of polymerization (corresponding to melt viscosity) of the copolymer. They learned that if the formula was satisfied, problems during tube molding could be eliminated and an elastomer tube with good moldability and excellent flexibility and aging resistance could be obtained. In particular, the fact that a tube with a bending radius of up to 4 mm can be obtained means that tube piping can be made more compact and lightweight, and it will not bend and interfere with the transfer of internal liquid or gas. This facilitates reliable tube design. The copolymers of the present invention exhibit comparable elastic performance at lower polyether contents compared to conventional polyether esters made from polybutylene terephthalate and poly(tetramethylene oxide) glycol, and also exhibit comparable elastic performance at lower melting temperatures (processing temperatures). Since it can be used as an elastomer with low heat resistance and weather resistance, it can be used as an elastomer with excellent heat resistance and weather resistance, but depending on the application, even higher stability is required. In this case, stability can be further enhanced by adding stabilizers such as antioxidants and ultraviolet absorbers. Typical antioxidants include hindered phenol compounds, aromatic amine compounds, phosphate ester compounds, etc., and light stabilizers include penzotriazole compounds, benzothiazole compounds, organic phosphorus compounds, etc. , can be added in a proportion of about 0.005 to 3.0% by weight based on the polymer before and during polymerization or before forming a tube or the like. Now, the method for forming the polyester elastomer tube according to the present invention is not particularly limited, and conventionally known methods can be employed.

That is, generally, it can be obtained by molding the molten material from an extruder through a die into a cylindrical shape, then using a homing device to shape and cool it into a circular shape with a predetermined size, and then passing it through a take-off machine and cutting it into a predetermined length. can. At this time, if the melt viscosity of the polymer composition used in the tube molded product of the present invention is low or if the solidification time is long, the homing part may be formed using an internal pressure method in order to maintain the circular shape and dimensions of the molten tube extruded from the die. The objective is to adjust the length of the cooling zone, the cooling temperature, and reduce the frictional resistance of the sliding surface so that the molten tube can be sufficiently cooled and solidified and the roundness can be formed using the vacuum homing method. It is possible to obtain a tube molded body.

The tube molded article according to the present invention obtained in this way can be easily molded without the need for vulcanization, has flexibility comparable to rubber, has a small minimum bending radius, has a high modulus at high temperatures, and has a high modulus at low temperatures. It has desirable properties that could not be achieved with existing single materials. Taking advantage of these excellent properties, we have developed various types of tubes and hoses, especially water pressure tubes (hoses) that require heat resistance and cold resistance.
It can be used for hoses), gasoline tubes (hoses), exhaust gas tubes, etc.

The present invention will be explained in detail below using examples.

Example 1 Polymer sail: 94.5 parts of dimethyl terephthalate, 41.3 parts of dimethyl isophthalate, 62.5 parts of poly(tetramethylene oxide) glycol having a number average molecular weight of about 1000. part and 1
, 94.5 parts of 4-butanediol and 0.1 part of a titanium tetrabutoxide catalyst were charged into a reaction vessel equipped with an IJ Calribbon-type impeller, and heated to 210°C for 2 hours to reach the theoretical distillate amount of ethanol. 95% of methanol was released outside the system.

10,980.42 parts of Irganox® was added to the reaction mixture, and then three powders were added to reduce the pressure in the system to 0.2 feet Hg, and polymerization was carried out under these conditions for 3 hours. The sticky steel polymer was extruded into water in a gut shape and made into chips.The relative viscosity (Rr) of this polymer was 1.95.
The melting point was 160°C. Polymer Tsukuda 101.6 parts of dimethyl terephthalate, 33 parts of dimethyl isophthalate. 100.0 parts of poly(tetramethylene oxide) glycol having a number average molecular weight of about 1000,
113.5 parts of 1,4-butanediol was transesterified at 190 qo for 2 hours using 0.05 part of oxidized impropyl titanate as a catalyst, and then 0.15 parts at a temperature of 250 oo
Polymerization was performed under reduced pressure of side Hg for 3 hours, and the relative viscosity was 2.2.
0 and a polyether ester with a melting point of 16,500.

Polymer (C) 81.3 parts of terephthalic acid, 31.1 parts of phthalic anhydride, 1.35 parts of trimellitic anhydride together with 0.085 parts of 1,4-butanediol 11% titanium-n-butoxide Pour into the reaction container and increase to 18,000 in 3 minutes.
The temperature was raised to 21,000 in 0 minutes, and the distilled water was distilled out of the system.

After heating at 210°C for 3 minutes, the number average molecular weight is approximately 2.
000 poly(tetramethylene oxide) glycol 7
0. 58 parts of Antigen' FO (antioxidant) was added to the dark area, and the temperature was raised to 2360°C, and the system was brought to below 1 Hg over 40 minutes.

Subsequently, the temperature of the liquid was raised to 24,500 and the military condensation proceeded. After 2 hours, the relative viscosity (R) was 1.80 and the melting point was 15.
80 polyether esters [0 obtained. The above polymers, 'B) and (C} are respectively on the caliber 65 side, L/D22
The product was extruded into a cylindrical shape through a die at a temperature of 210 CO and passed through a vacuum homing device with the sliding surface temperature adjusted to 15oC to obtain a tube molded product with an outer diameter of 7 legs and an inner diameter of 5 willow.

Table 1 shows the physical properties of the three types of tubes obtained. Table 1 Example 2 Polymer ■ was heated to 200qC on the diameter 45 side, L/
It was extruded from a D23 extruder into a cylindrical shape through an internal pressure tube forming die, passed through a sizing plate, and cooled in water at 5°C to obtain a tube molded product with an outer diameter of 8 bars and an inner diameter of 3.5 ribs.

Claims (1)

[Scope of Claims] 1. A dicarboxylic acid or an ester-forming derivative thereof consisting of 80 to 60 mol% of terephthalic acid and 20 to 40 mol% of isophthalic acid or phthalic acid, 1,4-butanediol, and a number average molecular weight of about 500 to 3,000 poly(tetramethylene oxide) glycol or an ester-forming derivative thereof, the copolymer containing 25 to 50% by weight of the poly(tetramethylene oxide) glycol units in the polymer, and A polymer whose solution viscosity satisfies the following formula η_r≧1.45+0
．． 65P η_r: Relative viscosity p: Polyester elastomer tube consisting of the weight fraction of poly(tetramethylene oxide) glycol units in the polymer.