JPS61115924A - Thermoplastic block copolymer - Google Patents

Abstract

PURPOSE:The titled copolymer which can show good tensile strength, abrasion resistance and flexural fatigue resistance over a wide temperature range, comprising a specified crystalline polyester segment and a specified amorphous polyether segment which are bonded with each other through amide and urethane bonds. CONSTITUTION:A thermoplastic block copolymer having a crystalline polyester segment and an amorphous polyether segment which are obtained by reacting a carboxyl-terminated crystalline polyalkylene phthalate of a MW of 300-3,000 and a polytetramethylene glycol with a diisocyanate, wherein these segments are bonded with each other through amide and urethane bonds. Said copolymer can show excellent tensile strentth, abrasion resistance and flexural fatigue resistance in a wide temperature range, e.g., -40-80 deg.C and can find various applications because it can be processed by extrusion, injection, blow molding, etc.

Description

Detailed Description of the Invention Industrial Application Field 2 The present invention is a novel thermoplastic that has good tensile strength, abrasion resistance, and bending fatigue resistance in a wide temperature range from low to high temperatures. Regarding block copolymers.

Prior art and problems to be solved by the invention: Polyurethane resin has been used as a material with better wear resistance and bending fatigue resistance than before, but liquid prepolymers are usually used for casting and molding. poor productivity,
Therefore, it is thermoplastic and can be easily formed into molded products or films by methods such as injection, extrusion, and blow molding, and has good tensile strength, abrasion resistance, and bending fatigue resistance in a wide temperature range from low to high temperatures. There is a desire to develop resins with this property.

A foolproof way to solve a problem.

As a result of intensive studies to satisfy these demands, the present inventors discovered the usefulness of a block copolymer having a specific structure and arrived at the present invention.

That is, the present invention provides (A) a number average molecular weight of 300 to 300;
It has a crystalline polyester segment and an amorphous polyether segment formed by reacting a crystalline polyalkylene phthalate having a 00 carboxyl group at the end, (B) polytetramethylene glycol and a (q diisocyanate compound, and the segment has an amide bond. and thermoplastic block copolymers bonded by urethane bonds.

The crystalline polyalkylene phthalate mentioned in (5) above can be used in combination with para- or meta-substituted aromatic dibasic acids such as terephthalic acid and isophthalic acid, or other dibasic acids or their anhydrides within a range that does not inhibit crystallinity. Neopentyl glycol,
Ethylene glycol, 1,4-butanediol, 1,6
-It is typically obtained by reacting diols with symmetrical molecular structures such as hexanediol and dodecanediol in a ratio in which the carboxyl group of the dibasic acid is in excess of the diol, but aromatic substances such as dimethyl terephthalate After condensing the group dibasic acid ester with excess diol by transesterification reaction and hydroxylating all the molecular ends,
Furthermore, the terminal of the molecule may be converted to a carboxyl group by reacting with other dibasic acids or dibasic acid anhydrides. In this case, phthalic anhydride, succinic anhydride, adipine Dibasic acids other than para- or meta-substituted aromatic dibasic acids such as sebacic acid may also be used.

Alternatively, after ring-opening addition of terephthalic acid or isophthalic acid and ethylene oxide or tetrahydrofuran, an esterification reaction with a dibasic acid may be performed (.

In order to maintain the crystallinity of the crystalline polyalkylene phthalate in the holes and to obtain the wear resistance of the present invention, the dibasic acids include para- or meta-substituted aromatic dibasic acids, The proportion is preferably 70 mol% or more, particularly preferably 80 mol or more.

^ Regarding the terminal groups of the crystalline polyalkylene phthalate in (3) above, it is preferable that 80 equivalent% or more of the terminal groups are carboxyl groups, but there is no problem even if the esterification reaction is incomplete and hydroxyl groups remain. The molecular weight of the crystalline polyalkylene phthalate in (8) above is estimated from the measurement of the acid value and hydroxyl value of the produced resin, and is the value obtained by dividing the weight of the produced resin (f) by the sum of the number of equivalents of carboxyl groups and hydroxyl groups. The molecular weight ranges from 300 to 3000. However, when the molecular weight is less than 300, the toughness of the resin decreases and
If it is more than 000, the abrasion resistance decreases and is inappropriate;
A range of 0 to 2500 is particularly preferred.

The polytetramethylene glycol (B) above is a polyether diol obtained by ring-opening polymerization of tetrahydrofuran, and constitutes the amorphous portion of the block copolymer of the present invention, and has particularly good resistance to bending fatigue in cold weather. Contribute to the improvement of The molecular weight of the polytetramethylene glycol in [F]) above is generally 300 to 3,000, but 400 to 1
A range of 500 is preferred.

Examples of the diisocyanate [C) above include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, synchronohexylmethane diisocyanate, hydrogenated xylylene diisocyanate, inphorone diisocyanate, α, α,
α', d-Tetramethylparaxylylene diincyanate, α.

Various diinsyanates are used such as α, α′, α′-tetramethyl metaxylylene diisocyanate, but for applications that require weather resistance, hexamethylene diisocyanate, synchrohexylmethane diisocyanate, and hydrogenated xylylene diisocyanate are used. , inphorone diisocyanate, α, α, α′, α′-tetramethyl paraxylylene diisocyanate, α, α, α′.

Weather resistance can be imparted by using a so-called non-yellowing isocyanate such as α'-tetramethyl metaxylylene diisocyanate. In order to obtain weather resistance and especially fatigue resistance and tensile strength in a wide temperature range, α, α, α′, α′-tetramethyl paraxylylene diincyanate, α, which has an aromatic ring and is non-yellowing. α, α′
, α'-tetramethyl metaxylylene diisocyanate is most preferably used.

The above (B) polytetramethylene glycol and the above (C)
The diisocyanate compound of ) is usually prepared in such a manner that the isocyanate group of the diisocyanate compound is in excess of the hydroxyl group of polytetramethylene glycol and reacted in advance to form a prepolymer with terminal incyanate groups in which the hydroxyl group has disappeared, and then the above-mentioned diisocyanate compound is prepared. The method (8) of reacting with crystalline polyalkylene phthalate is adopted. In this case, the equivalent ratio of diinosinate group to hydroxyl group is preferably in the range of 2.1 to 2:1.6, and 2:
1 to 221.3 is particularly preferred in order to maintain tensile strength at high temperatures.

The ratio of the terminal incyanate group prepolymer obtained as described above and the crystalline polyalkylene phthalate (3) above is determined by the number of equivalents of isocyanate groups and the number of equivalents of terminal groups of polyalkylene phthalate (carboxyl groups and remaining hydroxyl groups). The ratio of the sum of the number of equivalents of the groups is 0.95:
1-1. o521 range, more preferably 0.97:
The reaction is carried out at a weight ratio of 1 to 1.03:1. If the ratio of equivalent numbers deviates significantly from this range, the molecular weight of the resulting block copolymer will naturally become too small, resulting in a decrease in the physical strength of the resulting thermoplastic block copolymer.

The reaction with the incyanate prepolymers derived from the above-mentioned free crystalline polyalkylene 7-talate, fB) and (C) is usually carried out at a temperature higher than the melting point of the crystalline polyalkylene phthalate and can be physically stirred and mixed to produce the desired product. The temperature at which thermal decomposition of the copolymer is difficult to occur, that is, usually 130~
Usually 80-16 in an organic solvent capable of dissolving polyalkylene phthalate without solvent or inert at a temperature of 200°C.
The reaction can be carried out at 0°C, and then the solvent is removed under reduced pressure or the resulting copolymer is precipitated into a solvent that does not dissolve it.

The thermoplastic block copolymer of the present invention can be obtained in a solid state by precipitation and drying. This reaction is mainly a decarboxylation reaction between a carboxyl group and an incyanate group, producing an amide bond.On the other hand, some of the hydroxyl groups remaining in (8) crystalline polyalkylene 7-talate react with the isocyanate group. to form a urethane bond. The weight average molecular weight of the obtained thermoplastic copolymer of the present invention is generally in the range of 20,000 to 300,000, and particularly in the range of 30,000 to 150,000, in terms of physical properties such as tensile strength and Preferable from the viewpoint of moldability.

The thermoplastic block copolymer of the present invention obtained as described above has excellent tensile strength, abrasion resistance, and flexural fatigue resistance in a wide temperature range such as -40°C to 80°C. , and can be molded in the same way as conventional thermoplastic resins, such as extrusion molding, injection molding, and blow molding, making it a cheap packaging material.

It can be applied to a wide variety of applications such as hoses, cords, vibration-proofing materials, floor materials, gaskets, tire materials, metal coatings, coatings for wires such as electric wires and optical fibers, and film-like hot melt adhesives.

In addition, when the thermoplastic block copolymer of the present invention is put into practical use, various fillers such as coloring pigments, extender pigments, reinforcing fibers such as glass fibers and metal fibers, flake-conditioning materials such as glass flakes and mica, and antioxidants are added. ,
Auxiliary agents such as ultraviolet absorbers, mold release agents, lubricants, and plasticizers can be mixed and used depending on the purpose. Furthermore, the thermoplastic block copolymer of the present invention can also be mixed with other thermoplastic resins, such as polyvinyl chloride, polyvinylidene chloride, polyester, polyamide, polyurethane resins, etc. It is.

The present invention will be specifically explained below using Examples.

Example Synthesis of crystalline polyalkylene phthalates.

Example 1 828 parts by weight of bishydroxyethyl terephthalate (an addition reaction product of terephthalic acid and ethylene oxide) and 6 parts by weight of isophthalic acid were placed in a reactor equipped with a stirrer, a condenser, and a thermometer.
Charge 64 parts by weight, heat and melt, and bring the final reaction temperature to 23.
The reaction was carried out while raising the temperature to 0° C. and distilling off the water produced. The time from the start of distillation of the produced water to the end of the reaction is 8
It was time. The obtained polyalkylene phthalate (8
) shows crystallinity, and from the measurement of acid value and hydroxyl value, 1.53 equivalents of carboxyl group and 0.0 equivalent of carboxyl group in 1000f of resin.
The average molecular weight was estimated to be 1,234 from this value.

Example 2 830 parts by weight of isophthalic acid and 472 parts by weight of 1,6-hexanodiol were charged into the reactor used in Example 1, heated and melted, and the final reaction temperature was raised to 230°C. The reaction was carried out while distilling off. The time from the start of elution of the produced water to the end of the reaction was 7 hours. The obtained polyalkylene phthalate (B) showed crystallinity, and from the measurement of acid value and hydroxyl value, 2.1g in resin iooog was found.
It had an equivalent amount of carboxyl groups and 0.48 equivalents of hydroxyl groups, and from these values, the average molecular weight was estimated to be 749.

Example 3 970 parts by weight of dimethyl terephthalate, 495 parts by weight of 1,4-butanediol, and 2 parts by weight of tetrabutoxytitanium as a catalyst were charged into the reactor used in the example process, heated and melted, and the final reaction was carried out. The temperature was raised to 220°C, and the reaction was carried out while distilling off the methanol produced.The time from the start of distillation of the methanol produced until the end of the reaction was 6 hours. The number of equivalents was 0.87 equivalents, and the terminal groups were all hydroxyl groups based on the amount of methanol dehydrated and the results of nuclear magnetic resonance analysis.

Next, 100 parts by weight of succinic anhydride was added and mixed by heating at 140°C for 4 hours, and the disappearance of succinic anhydride was confirmed by infrared absorption spectrum.
) was obtained. Resin ioo from measurement of acid value and hydroxyl value
Contains 0.81 equivalent of carboxyl group and 0.01 equivalent of hydroxyl group in og, and the estimated average molecular weight is 249
It was 0.

Example 4 In the reactor used in Example 1, 830 parts by weight of isophthalic acid, 146 parts by weight of adipic acid, 5 parts by weight of neopentyl glycol
20 parts by weight and 100 parts by weight of xylene as a solvent for washing off sublimated neopentyl glycol from the condenser were charged and melted by heating.

The final reaction temperature was raised to 240°C, and the reaction was carried out while distilling off the produced water. Finally, the solvent xylene was removed under reduced pressure. The time from the start of dehydration to the end of the reaction was 9 hours. The resulting polyalkylene phthalate () showed crystallinity, and measurements of acid value and hydroxyl value revealed that the resin was 100 (
It had 1.81 equivalents of carboxyl groups and 0.30 equivalents of hydroxyl groups per liter, and the estimated average molecular weight was 945 from these values.

Reaction of polytetramethylene glycol and diiso7anate: Example 5 Into a reactor equipped with a stirrer, a thermometer, and a condenser, 500 parts by weight of dimethylformamide and 500 parts by weight of diphenylmethane diisocyanate were added, heated and stirred, and heated to 60°C. While maintaining the temperature in the reactor, 1000 parts by weight of polytetramethylene glycol with a molecular weight of 1000 was added in 10 portions every 15 minutes, and after the addition was completed, the reaction was completed by keeping the temperature at 60°C for 2 hours to complete the incyanate prepolymer (1). A 75% solution of The isocyanate group content was measured by titration, and it was confirmed that the inocyanate group content was 1.33 equivalents per 1000 f of solid content.

Example 6 In the reactor used in Example 5, 488 parts by weight of α, α1
α', α'-tetramethyl paraxyline diisocyanate was charged, and when the temperature reached 130°C while heating and stirring, 1500 parts by weight of polytetramethylene glycol having a molecular weight of 500 was added in 10 parts every 15 minutes. After the addition was completed, the reaction was further maintained at 130° C. for 2 hours to complete the reaction, yielding incyanate polymer (2).

Incyanate group content is 2.0 in solid content 1ooop
It was 2 equivalents.

Example 7 In the reactor used in Example 5, 439 parts by weight of α, α,
α',α'-tetramethyl metaxylylene diisocyanate was charged, and when the temperature reached 130°C while stirring, polytetramethylene glycol 8 with a molecular weight of 1000 was added.
00 parts by weight was added and reacted in the same manner as in Example 6 to obtain incyanate prepolymer (3). Incyanate group content is.

The amount was 1.11 equivalents per 1000 g of solid content.

Example 8 Into the reactor used in Example 5, 444 parts by weight of inphoron diincyanate was charged, and 110 parts by weight was heated and stirred.
When the temperature reached .degree. C., 500 parts by weight of polytetramethylene glycol having a molecular weight of 500 was added in the same manner as in Example 6, and a reaction was carried out to obtain incyanate prepolymer (4). The incyanate group content is 2.
It was 12 equivalents.

Production of thermoplastic block copolymers: Each of the polyalkylene phthalates (A) to (■) produced in Examples 1 to 4 and each of the incyanate prepolymers (1) to (4) produced in Examples 5 to 8 ) and an organic solvent as necessary in the weight proportions listed in Table 1 using a stirrer.

The mixture was charged into a reactor equipped with a thermometer and a condenser, and reacted under the temperature and time conditions listed in Table 1 while flowing nitrogen gas.

In addition, when an organic solvent was used, the organic solvent was distilled off under vacuum to obtain each thermoplastic block copolymer (I) to (X). still,
The weight molecular weight of each block copolymer measured by GPC method is also listed in Table 1.

Evaluation of thermoplastic block copolymers.

Thermoplastic block copolymers (I) to (X
) using an extruder with a screw diameter of 1) mtφ.
Extruded through a T-die at a temperature of 40-150℃, 50℃
The film was wound up through a cooling roll to obtain a 50μ film.

Abrasion resistance of the obtained film, -40℃, 20℃60℃
Table 2 shows the test results of tensile strength, elongation at break, and bending fatigue resistance at each temperature, as well as the weather-o-meter irradiation test results.

Claims (1)

[Claims] 1. A crystalline polyester segment obtained by reacting (A) a crystalline polyalkylene phthalate having a carboxyl group at the end with a molecular weight of 300 to 3,000, (B) polytetramethylene glycol, and (C) a diisocyanate compound. and a thermoplastic block copolymer having amorphous polyether segments, which segments are bonded by amide bonds and urethane bonds.