JPH0678413B2 - Thermoplastic resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel thermoplastic resin composition having excellent weather resistance, flexibility and abrasion resistance.

Conventional technology and its problems: Conventionally, polyurethane resins have been expected to be used for many purposes because they have excellent physical properties such as flexibility and abrasion resistance, but generally, they have poor weather resistance and Since it is easy to form a branched structure by a side reaction in the manufacturing process, it is difficult to mold by injection molding etc. and it has not been fully used as a thermoplastic resin, and it is mainly used as a thermosetting resin. Came.

Means for Solving the Problems: The present invention overcomes the disadvantages of conventional thermoplastic polyurethane resins, maintains weather resistance and flexibility, is easy to extrude and injection mold, and is weather resistant. An excellent novel polyester polyurethane-based thermoplastic resin composition is provided.

That is, (A) a hydroxyl group-terminated polyalkylene phthalate having a number average molecular weight of 300 to 3,000, and (B) a chain extender of the formula (I) It is obtained by reacting a diisocyanate represented by the formula (1) with an equivalent ratio (OH / NCO) of 0.9 to 1.1 and carrying out a urethanization chain extension reaction until the weight average molecular weight becomes 20,000 to 300,000. It is a thermoplastic resin composition.

Examples of the polyalkylene phthalate (A) include phthalic acid-based compounds such as terephthalic acid, dimethyl terephthalate, isophthalic acid, phthalic anhydride such as phthalic anhydride, orthophthalic acid, phthalic anhydride and alcohol esters of phthalic acid. For example, ethylene glycol, propylene glycol, 1,4 butanediol, 1,3 butanediol,
Neopentyl glycol, 1,5-pentanediol, 1,6
Esters with alkylene glycols such as hexanediol and dodecanediol can be produced by dehydration condensation or transesterification by a conventionally known method.

At this time, the number average molecular weight of the polyalkylene phthalate is adjusted by making the equivalent number of the hydroxyl group of the alkylene glycol excess over the equivalent number of the carboxyl group (including the anhydride and alcohol ester groups) of the phthalic acids, Therefore, it is important to complete the above dehydration condensation or transesterification reaction as much as possible to make both molecular terminals of polyalkylene phthalate hydroxyl groups, and to compare with the theoretical value by measuring the OH value at the end of the reaction. The reaction rate is calculated from, and the reaction rate based on carboxyl (or carboxyl alkyl ester) is 95% or more, preferably 98%
Try to be above. Further, the number average molecular weight of the above-mentioned (A) polyalkylene phthalate is calculated from the measurement of OH value, and since the reaction rate is sufficiently high, twice the equivalent weight per OH group is defined as the number average molecular weight.

Thus, if the number average molecular weight is less than 300, the flexibility is insufficient, and if the number average molecular weight is 3,000 or more, the abrasion resistance decreases, which is unsuitable, and particularly, the number average molecular weight is in the range of 500 to 2,000. preferable.

Further, among the above-mentioned phthalic acid compounds, those having a terephthalic acid skeleton and an isophthalic acid skeleton are preferable,
Among the above alkylene glycols, ethylene glycol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol and 1,6-hexanediol are particularly preferable.

The above (B) general formula The diisocyanate having the structure of α, α, α ′,
α'-Tetramethylmethaxylylene diisocyanate and α, α, α ', α'-tetramethylparaxylylene diisocyanate.

The above-mentioned (B) diisocyanate has an equivalent ratio of the isocyanate group to the hydroxyl group of the above-mentioned polyalkylene phthalate (A) of 1: 0.9 to 1: 1.1, preferably 1: 0.95 to
The thermoplastic resin composition of the present invention is obtained by addition condensation at a weight ratio of 1: 1.05. At this time, two or more kinds of polyalkylene phthalate (A) and two or more kinds of diisocyanate (B) may be used at the same time.

In the reaction of conventionally widely used diisocyanates, for example, polyhydroxy compounds such as tolylene diisocyanate or diphenylmethane diisocyanate, the by-product of allophanate is produced at a temperature at which the viscosities of the resulting resins are mixed and the reaction can proceed uniformly. As a result, branching occurs, and it is difficult to obtain a moldable resin. Also, since it is necessary to proceed the reaction in a large amount of organic solvent at a low temperature for controlling side reactions, the energy and Productivity is extremely poor in terms of volumetric efficiency. On the other hand, the above-mentioned diisocyanate (B) has a slow reaction to the hydroxyl group and is less likely to produce allophanate as a by-product. Therefore, at a temperature at which a viscosity capable of a uniform reaction is exhibited, for example, a temperature of 100 to 200 ° C. The resin composition of the present invention can be manufactured without using an organic solvent. Of course, it does not prevent the use of an inert organic solvent in this reaction process.

Usually, the above (A) alkylene phthalate is added at 100 to 200 ° C.
The above-mentioned diisocyanate (B) is dividedly or continuously added to the solution to be subjected to addition condensation during heating and dissolution. The preferred temperature condition is 120 to 180 ° C., and 140 to 180 when no organic solvent is used. The range of ° C is particularly preferred.

However, when an organic solvent is used, the reaction temperature may be 100 ° C. or lower, and a reaction accelerator such as organic tin, organic lead, and a tertiary amine may be used in combination. When an organic solvent is used, the organic solvent is distilled off in a vacuum, or the resin composition of the present invention is poured into a solvent that does not dissolve, for example, hydrocarbons with stirring, to cause coagulation and precipitation, and then to dry the product. The thermoplastic resin composition of the invention can be obtained.

It is preferable that the thermoplastic resin composition of the present invention has a weight average molecular weight of 20,000 or more from the viewpoint of strength of the obtained molded product sheet and the like, and particularly in the range of 30,000 to 300,000 for moldability and strength. It is preferable from both sides.

The thermoplastic resin composition of the present invention has excellent weather resistance, flexibility, adhesiveness and abrasion resistance, so that packaging materials, building materials, metal coating materials, hot melt adhesives, pipes,
It can be used for a variety of applications such as coating materials for gaskets, electric wires, wire materials such as optical fibers, etc., and also for ordinary thermoplastic resin processing methods such as film formation by extrusion molding, injection molding, extrusion coating, and press processing. Therefore, the above-mentioned applications are applied.

Further, in the practical use of the thermoplastic resin composition of the present invention, a filler such as a coloring pigment, an extender pigment, a glass fiber, a reinforcing fiber such as a metal fiber, an antioxidant, an ultraviolet absorber, a release agent, a lubricant, etc. It is possible to use the auxiliary agents according to the purpose.

It is also possible to use the thermoplastic resin composition of the present invention in combination with other thermoplastic resin or thermosetting resin.

Hereinafter, the present invention will be specifically described with reference to examples.

Example Synthesis of polyalkylene phthalate: In a reactor equipped with a stirrer, a condenser, and a thermometer, the respective raw materials (A) to (D) shown in Table 1 were charged and heated to an internal temperature of 150 ° C. When the reaction temperature reached 0.1%, tetrabutoxytitanium was added as a reaction accelerator in an amount of 0.1% by weight based on the charged weight of the raw materials, and the produced water or methanol was distilled off while the internal temperature was adjusted to 15 hours / hour.
The temperature is raised at a rate of ℃, and the temperature is maintained at 210 ℃ at the end, and the reaction is carried out for the time shown in Table 1 (the time from the start of dehydration or demethanol to the end of the reaction) to give each polyalkylene phthalate (A) to (D). ) Got. The reaction rates and number average molecular weights obtained by measuring the OH values of (A) to (D) are also shown in Table 1.

Synthesis of Polyester Polyurethane Thermoplastic Resin by Addition Condensation: The polyalkylene phthalate and solvent (in the case of experiment number (2)) in the weights shown in experiment numbers (1) to (6) of Table 2 are stirred with a stirrer and at a temperature. The mixture was placed in a reactor equipped with a meter, an aggregator and a nitrogen inlet, dissolved by heating, and when the temperature reached to each experiment number in Table 2 was reached, the diisocyanate described in Table 2 was divided into 10 parts and added every 10 minutes. It was During this period, nitrogen was flown into the gas phase and stirring was continued, and the reaction was carried out while maintaining the temperature shown in Table 2 for a total of 3 hours from the start of the addition of diisocyanate.

In the case of the experiment number (2), the temperature was raised to 160 ° C., and then the solvent was distilled off in a vacuum. It was confirmed from the infrared absorption spectrum of the residual isocyanate groups that the reactions of the obtained thermoplastic resins of the experiment numbers (1) to (6) proceeded almost quantitatively. The weight average molecular weight of each resin was measured by the GPC method (polystyrene conversion value) and is also shown in Table 2.

Evaluation of thermoplastic resin: Each of the thermoplastic resins of Experiment Nos. (1) to (6) was extruded through a T-die at each temperature shown in Table 3 using an extruder having a screw diameter of 40 mmφ and wound through a cooling roll of 50 ° C. A film of about 50 μm was obtained.

The obtained film was tested for tensile strength, elongation, abrasion resistance and irradiation with a weather ometer, and the results are shown in Table 3.

Comparative Example 1 1,000 parts by weight of the above polyalkylene phthalate (A) was charged into a reactor similar to the thermoplastic resin of the above example and heated, and when reaching 150 ° C., 176 parts by weight of tolylene diisocyanate was divided into 10 parts. , Every 10 minutes. 150 ° C
The mixture was kept under a constant flow of nitrogen and was continuously stirred, but gelation occurred immediately after the sixth addition of tolylene diisocyanate, and the reaction was neutralized by making stirring impossible.

Comparative Example 2 1,000 parts by weight of the above polyalkylene phthalate (A) and 1,176 parts by weight of dimethylformamide were charged into a reactor similar to the above and heated, and when reaching 80 ° C., 176 parts by weight of tolylene diisocyanate was added to 10 parts by weight. It was divided and added every 10 minutes. During this time, nitrogen was flown into the gas phase and stirring was continued, and the reaction was carried out at 80 ° C. for a total of 3 hours from the start of the addition of tolylene diisocyanate. Next, dimethylformamide was distilled off in a vacuum while gradually raising the temperature. From the infrared absorption spectrum of the residual isocyanate group, it was confirmed that the reaction of the obtained resin proceeded almost quantitatively. The weight average molecular weight of this resin was 75,000.

The above resin was formed into a film of about 50 μm in the same manner as in the example, and the evaluation was performed in the same manner as in the example. The evaluation results of this comparative example are also shown in Table 3.

Claims (1)

[Claims] 1. A hydroxyl group-terminated polyalkylene phthalate having a number average molecular weight of 300 to 3,000, and (B) a chain extender of the formula (I). It is obtained by reacting a diisocyanate represented by the formula (1) with an equivalence ratio (OH / NCO) of 0.9 to 1.1 and performing a urethanization chain extension reaction until the weight average molecular weight becomes 20,000 to 300,000. Thermoplastic resin composition.