JPH0586419B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new thermoplastic resin that has excellent weather resistance, cold and cold flexibility, and abrasion resistance. Polyurethane resin has traditionally been expected to be used in many applications due to its excellent physical properties such as flexibility and abrasion resistance, but it generally has poor weather resistance and has a branched structure due to side reactions during the resin manufacturing process. Since it is easy to make, it is difficult to mold it by injection molding etc., and the actual situation is that it cannot be used sufficiently as a thermoplastic resin, so it has been mainly used as a thermosetting resin. The present invention provides a new polyester polyurethane thermoplastic resin that overcomes the drawbacks of conventional thermoplastic polyurethane resins, has excellent weather resistance and flexibility especially in cold weather, and is easy to extrude and injection mold. It is. The thermoplastic resin according to the present invention contains (A) 50 to 95% by weight of hydroxy-terminated polyalkylene phthalate with a number average molecular weight of 300 to 3,000, and (B) 50 to 95% by weight of polytetramethylene glycol with a number average molecular weight of 400 to 3,000. 5% by weight of the diol components, and (C) general formula

A diisocyanate represented by the formula is selected and used, and the final molar equivalent ratio of hydroxyl group (-OH) to isocyanate (-NCO) is 1:0.9 to 1:1.1.
The polyether urethane chain length and the polyester urethane chain length are shared in the same molecular chain, and the following formula is obtained by performing the urethanization chain length forming reaction in the range of

[ka]

[ka]

[Formula] (In the formula, R ¹ is a C ₂ - C ₁₂ optionally branched alkylene group, R ² is a tetramethylene group, and n is 1 to 10
m is an integer from 3 to 12, and x is 1 or 2. ) is characterized by having a weight average molecular weight of 30,000 to 300,000. The above polyalkylene phthalate (A) is a phthalic acid compound such as terephthalic acid, dimethyl terephthalate, isophthalic acid, phthalic anhydride, orthophthalic acid, phthalic anhydride, or alcohol esters of phthalic acid. , for example, ethylene glycol, propylene glycol, 1,
4-butanediol, 1,3-butanediol, neopentyl glycol, 1,5-pentanediol,
It is an ester with alkylene glycols having 2 to 12 carbon atoms such as 1,6 hexanediol and dodecanediol, and is produced by dehydration condensation or transesterification reaction by conventionally known methods. At this time, the number average molecular weight of the polyalkylene phthalate can be adjusted by making the number of equivalents of the hydroxyl group of the alkylene glycol in excess of the number of equivalents of the carboxyl group (including anhydride and alcohol ester groups) of the phthalic acid. . Therefore, it is important to complete the dehydration condensation or transesterification reaction as much as possible so that both molecular ends of the polyalkylene terephthalate become hydroxyl groups. At this time, the reaction rate is calculated from the comparison with the theoretical value by measuring the OH value at the end of the reaction.
The reaction rate based on carboxyl (or carboxyalkyl ester) is controlled to be 95% or more, preferably 98% or more. In addition, the number average molecular weight of the polyalkylene phthalate (A) above is calculated from the measurement of the OH value, and the weight (g) of the polyalkylene phthalate (A) is the sum of the number of equivalents of OH groups and the number of equivalents of unreacted terminal groups. Twice the value divided by is defined as the number average molecular weight. If the number average molecular weight is less than 300, the flexibility will be insufficient, and if it is more than 3,000, the abrasion resistance will decrease, making it unsuitable. In particular, the number average molecular weight is preferably 500 to 2,000. Among the above-mentioned phthalic acid compounds, those having a terephthalic acid skeleton and an isophthalic acid skeleton are preferred, and among the above-mentioned alkylene glycols, ethylene glycol, 1,4-butanediol, Neopentyl glycol and 1,6-hexanediol are particularly preferred. The polytetramethylene glycol (B) above is a diol with hydroxyl groups at both molecular ends obtained by ring-opening polymerization of tetrahydrofuran, and for the purpose of the present invention, one with a number average molecular weight of 400 to 3000 is used. do. Thus, polytetramethylene glycol contributes to improving flexibility, especially during cold resistance. General formula (C) above

Diisocyanates having the structure of
α,α′,α′-tetramethyl paraxylylene diisocyanate. The above (C) diisocyanate has an isocyanate group equivalent number of 1:0.9 to 1:1.1, preferably 1:0.9 to 1:1.1, preferably 1:0.9 to 1:1.1 to the total number of equivalents of the hydroxyl groups of the above (A) polyalkylene phthalate and (B) polytetramethylene glycol. The thermoplastic resin of the present invention is obtained by addition condensation at a ratio of: 0.95 to 1:1.05. In addition, the usage ratio of (A) polyalkylene phthalate and (B) polytetramethylene glycol is such that (A) is 50 to
(B) is 50 to 5% by weight of the sum of (A) and (B) for 95% by weight.
100% by weight. ). If (A) is less than 50% by weight, the strength will be insufficient, and if (A) is more than 95% by weight, the flexibility in cold weather will decrease, making it impossible to achieve the object of the present invention. Especially when (A) is 60 to 90% by weight, (B)
is preferably 40 to 10% by weight. In the above reaction of (A) polyalkylene phthalate, (B) polytetramethylene glycol and (C) diisocyanate, (A), (B) and (C) may be reacted simultaneously, but ( It is preferred to pre-react either A) or (B) with an excess equivalent of diisocyanate and then add the remaining (A) or (B) to complete the reaction. In addition, in the reaction of a polyhydroxy compound with a diisocyanate that has been widely used in the past, such as tolylene diisocyanate or diphenylmethane diisocyanate, the viscosity of the resulting resin is sufficient to allow mixing and at a temperature that allows the reaction to proceed uniformly. , branching occurs with the by-product of allophanate, making it difficult to obtain a moldable resin, and it is necessary to proceed with the reaction in a large amount of organic solvent at low temperatures to control side reactions, which requires removal of the organic solvent. Productivity is significantly inferior in terms of energy required and volumetric efficiency. On the other hand, the above diisocyanate (C) has a slow reaction with hydroxyl groups and does not easily generate allophanate by-products, so it is kept at a temperature where the viscosity is sufficient to allow a uniform reaction, e.g. 100 to 200°C. In this method, the thermoplastic resin of the present invention can be produced without using an organic solvent. Of course, this does not preclude the use of an inert organic solvent in this reaction process.
That is, the reaction of the above (A) alkylene phthalate and (B) tetramethylene glycol with the above (C) diisocyanate can usually be carried out at 100 to 200°C. In addition, when using an organic solvent, 100
The reaction temperature may be lower than 0.degree. C., and a reaction accelerator such as organic tin, organic lead, or tertiary amine may be used in combination. When an organic solvent is used, the organic solvent is distilled off in vacuo, or the thermoplastic resin of the present invention is poured into a solvent such as hydrocarbons with stirring, coagulated and precipitated, and then dried. The thermoplastic resin of the present invention can be obtained in this manner. The thermoplastic resin thus obtained has a basic skeleton consisting of repeating units represented by the following formula.

[ka]

[ka]

[Formula] (Here, R ¹ , R ² , n, m and x have the same meanings as above.) The weight average molecular weight of the thermoplastic resin of the present invention is determined from the viewpoint of both moldability and the strength of the molded product obtained. 3
It is estimated to be between 30,000 and 300,000. The thermoplastic resin of the present invention has excellent weather resistance, flexibility in cold and cold conditions, and abrasion resistance. It can be used for a variety of purposes, such as coating materials for wire rods such as optical fibers, and it can also be applied to the above uses by ordinary thermoplastic resin processing methods such as extrusion film formation, injection molding, extrusion coating, and press processing. will be done. In addition, when putting the thermoplastic resin of the present invention into practical use,
colored pigments, extender pigments, and glass fibers;
Fillers such as reinforcing fibers such as metal fibers, auxiliary agents such as antioxidants, ultraviolet absorbers, mold release agents, and lubricants may be used depending on the purpose. It is also possible to use the thermoplastic resin of the present invention in combination with other thermoplastic resins or thermosetting resins. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Reference example Synthesis of polyalkylene phthalate In a reactor equipped with a stirrer, condenser, and thermometer,
Each of the raw materials (A) to (D) shown in Table 1 are charged, and when the internal temperature reaches 150°C, tetrabutoxytitanium is added as a reaction accelerator in an amount equivalent to 0.1% by weight based on the weight of the raw materials. In addition, while distilling off the water or methanol produced, the internal temperature was raised at a rate of 15°C per hour, and finally maintained at 210°C for the time shown in Table 1 (from the start of dehydration or methanol removal to the end of the reaction). time) to react each polyalkylene phthalate
(A) to (D) were obtained. The reaction rates and number average molecular weights of (A) to (D) determined from the OH value measurements are also listed in Table 1.

【table】

[Table] Note: The amounts of methanol in the raw materials and distilled water in the table are all parts by weight.
Ru.
Examples 1 to 6 (1) Synthesis of thermoplastic resin by addition condensation: Polytetramethylene glycol and diisocyanate in the weights shown in Examples 1 to 6 in Table 2 were mixed in a stirrer, thermometer, condenser, nitrogen inlet and The mixture was placed in a reactor equipped with a heatable dropping tank, heated and stirred while flowing nitrogen into the gas phase, and the first stage reaction was carried out at the temperature and time listed in Table 2. Next, each polyalkylene phthalate listed in Table 2 was heated and dissolved in a dropping tank, added to the reactor, and a second stage reaction was carried out at the temperature and time listed in Table 2. A thermoplastic resin was obtained. It was confirmed that the reaction of each resin proceeded almost quantitatively from the infrared absorption spectrum of the residual isocyanate group. In addition, the weight average molecular weight of each resin was measured by the GPC method (polystyrene equivalent value) and is also listed in Table 2.

【table】

[Table] Note: All values for raw materials in the table are parts by weight.
(2) Evaluation of thermoplastic resin: Each of the thermoplastic resins of Examples 1 to 6 was subjected to T at each temperature listed in Table 3 using an extruder with a screw diameter of 40 mmφ.
It was extruded through a die and wound up through a cooling roll at 50°C to obtain a 50μ film. The tensile strength and elongation of the obtained film were measured at room temperature and -40°C, and an abrasion resistance test and a weather-o-meter irradiation test were conducted, and the results are shown in Table 3. Comparative Example 1 Using an apparatus similar to that used in the synthesis of thermoplastic resin by addition condensation in the above-mentioned Example, 200 parts by weight of polytetramethylene glycol (number average molecular weight 500) and α, α, α', α'-tetramethyl were first mixed. After heating and mixing 866 parts by weight of metaxylylene diisocyanate at 140°C for 2 hours, 800 parts by weight of bishydroxyethylene terephthalate (molecular weight 254) was added and further heating and mixing at 150°C for 3 hours. After confirming that it had disappeared, a thermoplastic resin was obtained. The weight average molecular weight of this resin is 5.8
It was ten thousand. Using this resin, a 50μ film was obtained in the same manner as in the Examples, and evaluated in the same manner as in the Examples, and the results are also listed in Table 3. Comparative Example 2 1164 parts by weight of dimethyl terephthalate and 1,6-hexanediol were synthesized using the same apparatus as used for the synthesis of polyalkylene phthalate described in the above example.
767 parts by weight were charged, and 0.1% by weight of tetrabutoxytitanium was added to the above raw materials as a reaction accelerator, and the reaction was carried out for 24 hours in the same manner as in the example. The amount of methanol distilled was 768 parts by weight, calculated from the hydroxyl value, the reaction rate was 100%, and the number average molecular weight was 3094.
It was hot. 850 parts by weight of the above polyalkylene phthalate
Continue to melt at 140°C, add 104 parts by weight of α, α, α', α'-tetramethyl metaxylylene diisocyanate, heat for 2 hours, and then add 150 parts by weight of polytetramethylene glycol (number average molecular weight 1000). After reacting at 150°C for 4 hours, it was confirmed that the residual isocyanate groups had disappeared from the infrared absorption spectrum, and a thermoplastic resin was obtained. The weight average molecular weight of this resin was 79,000. Using this resin, a 50μ film was obtained in the same manner as in the examples, and evaluated in the same manner as in the examples. The results are also listed in Table 3. Comparative Example 3 40 parts by weight of the polytetramethylene glycol (number average molecular weight 500) and 265 parts by weight of α, α, α', α'-tetramethylmethaxylylene diisocyanate were reacted under the same conditions as in Experiment No. (1). Then add 960 parts by weight of the polyalkylene phthalate (A),
A second stage reaction was carried out under the same conditions as in Experiment No. (1) to obtain a thermoplastic resin with a weight average molecular weight of 56,000. A 50μ film was prepared and evaluated in exactly the same manner as in the example. The evaluation results are also listed in Table 3. Comparative Example 4 550 parts by weight of the polytetramethylene glycol (number average molecular weight 1500) and 268 parts by weight of α, α, α', α'-tetramethylmethaxylylene diisocyanate were reacted under the same conditions as in Experiment No. (5). Next, 450 parts by weight of the polyalkylene phthalate (C) was added, and a second stage reaction was carried out under the same conditions as in Experiment No. (5) to obtain a thermoplastic resin having a weight average molecular weight of 145,000.
A 50μ film was prepared and evaluated in exactly the same manner as in the example. The evaluation results are also listed in Table 3. Comparative Example 5 1000 parts by weight of polyalkylene phthalate (C) listed in Table 1 was dissolved at 150°C, and 397 parts by weight of α, α, α′,
α'-tetramethyl metaxylylene diisocyanate was added dropwise over 1 hour, and the mixture was heated and mixed at 150° C. for 2 hours to synthesize a thermoplastic resin of a comparative example.
The weight average molecular weight was 105,000. Next, a 50μ film was prepared and evaluated in the same manner as in the example. The results are also listed in Table 3.

【table】

Claims (1)

[Claims] 1. As a diol component, (A) number average molecular weight of 300 to
3,000 hydroxy-terminated polyalkylene phthalate and (B) polytetramethylene glycol having a number average molecular weight of 400 to 3,000 are used in a proportion of 50 to 5% by weight. As a urethanization chain lengthening agent for the diol component of B), (C)
A diisocyanate represented by the general formula [formula] is selected and used, and the final molar equivalent ratio of hydroxyl group (-OH) and isocyanate group (-NCO) is 1:0.9 to 1:
The polyether urethane chain length and the polyester urethane chain length are shared in the same molecular chain, obtained by carrying out the urethanization chain length forming reaction in the range of 1.1, and the following formula , R ¹ is a C ₂ -C ₁₂ optionally branched alkylene group, R ² is a tetramethylene group, n is 1 to 10
m is an integer from 3 to 12, and x is 1 or 2. ) A thermoplastic resin having a weight average molecular weight of 30,000 to 300,000, having a repeating unit represented by: