KR20080046390A - Composition for modified transparence and highly elastic recovery of aliphatic based thermoplastic polyurethane elastomer - Google Patents

Abstract

An aliphatic thermoplastic polyurethane resin composition is provided to improve transparency, elastic recovery, injection molding property and yellowing resistance. An aliphatic thermoplastic polyurethane resin composition comprises 10-86 wt% of a polyol having a number average molecular weight of 650-6,000; 10-60 wt% of a diisocyanate comprising 1,6-hexamethylene diisocyanate and at least one kind of aliphatic diisocyanate other than 1,6-hexamethylene diisocyanate; and 3-35 wt% of a C1-C20 chain extender, wherein the composition has a flexural deformation of 30% or less and a transparency(ASTM D1033) of 80% or more.

Description

Composition for modified transparence and highly elastic recovery of aliphatic based Thermoplastic polyurethane elastomer}

1 is a schematic view of a test method for evaluating the elastic recovery of the resin composition according to the present invention.

The present invention relates to an aliphatic thermoplastic polyurethane resin composition having excellent elasticity with improved transparency. More specifically, the present invention relates to an aliphatic thermoplastic polyurethane having improved transparency, including 1,6 hexamethylene diisocyanate and tetramethylxylene diisocyanate. It relates to a thermoplastic polyurethane resin composition.

Thermoplastic polyurethane (TPU) elastomers have long been known, and TPU is formed from linear polyols, generally polyester or polyether polyols, organic diisocyanates and short chain diols (chain extenders), with components having different chemical structures By using them, a wide range of changes in mechanical properties can be obtained, and in order to control the properties, the molar ratio of the structural components can be varied in a relatively wide range.

Thermoplastic polyurethanes have limitations in the application of products requiring such high elasticity because of the lowering of yellowing resistance due to the use of conventional aromatic diisocyanates, and the recovery of elasticity from other thermoplastic elastomers, in particular polyether block amide elastomers. In order to solve the above problem, the prior art is to increase the stiffness and modulus by using a filler such as glass fiber in the existing aromatic thermoplastic elastomer to increase the elastic recovery rate. However, these fillers can increase the stiffness, but there is a limit that the repetitive shock absorbing power (damping property) falls. In addition, thermoplastic polyurethane resins using hexamethylene diisocyanate, which is an aliphatic diisocyanate, have excellent elastic recovery, but have high crystallinity, and thus are limited in use due to a decrease in transparency compared to thermoplastic polyurethanes using an aromatic diisocyanate.

In addition, as a method for improving the transparency of the conventional polyurethane resin, a method of manufacturing a polyurethane resin having excellent transparency by changing the soft segment is known, which increases the compatibility with the hard segment of the polyol constituting the soft segment. In order to reduce the molecular weight of polyols having the same composition, transparency is excellent. However, when polyols having too small molecular weight are used, mechanical strength, cold resistance and heat resistance are weaker than those of polyols having large molecular weights. Therefore, there is a need for further development of a technology that satisfies elastic recovery and transparency at the same time.

An object of the present invention for solving the problems of the prior art is to provide a thermoplastic polyurethane resin composition having a high initial modulus, excellent elasticity recovery, low temperature bendability and yellowing resistance, and particularly improved transparency.

Polyurethane resin composition according to the present invention for achieving the above object,

a) 10 to 86% by weight of a polyol having a number average molecular weight of 650 to 6000,

b) 10 to 60% by weight of diisocyanate containing 1,6-hexamethylene diisocyanate (HDI) and at least one aliphatic diisocyanate except for HDI,

c) 3 to 35% by weight of a chain extender, wherein the composition has a bending strain of 30% or less and a transparency (ASTM D1033) of 80% or more.

Hereinafter, the present invention will be described in detail.

Aliphatic thermoplastic polyurethane resin composition having excellent elasticity and improved transparency according to the present invention is a) 10 to 86% by weight of a polyol having a number average molecular weight of 650 to 6000, b) 1,6-hexamethylene diisocyanate and the HDI 10 to 60% by weight of diisocyanate containing at least one aliphatic or cycloaliphatic diisocyanate except for c), and 3 to 35% by weight of a chain extender, wherein the composition is repeated 100 times by an improved method of ASTM D790. The bending strain after completion of the bending test is 30% or less, and the transparency (ASTM D1033) is 80% or more.

The present invention uses aliphatic diisocyanate and Shore hardness is about 60A to 80D, and preferably has a hardness of 65A or more and 75D or less and is characterized by improving transparency of the thermoplastic polyurethane resin composition having excellent yellowing resistance and elastic recovery rate.

The polyol included in the highly elastic aliphatic thermoplastic polyurethane resin composition having improved transparency of the present invention is polytetramethylene ether glycol (PTMEG), polycarbonate polyol, polybutylene adipate polyol (polybutylene adipate) , Polyhexylene adipate (polyhexylene adipate) and polycaprolactone polyol (polycaprolactone polyol) is preferably used one or more selected from the group consisting of.

It is preferable that the polyol contained in the said polyol is 1 type with the same molecular weight, or 2 or more types of polyol from which molecular weight differs. The number average molecular weight of the polyol used alone or in combination is preferably 650 to 6000, more preferably 1000 to 4000. In this case, when the number average molecular weight is less than 650, the mechanical properties are lowered, and when the number average molecular weight is greater than 6000, the transparency is lowered and it is not preferable because of brittleness.

The polyol content is used in an amount of 10 to 86% by weight based on the total composition of the high elastic aliphatic thermoplastic polyurethane resin having improved transparency, and when the content is less than 10% by weight, the elastic expression effect by the phase separation of the hard segment and the soft segment is achieved. Unexpectedly, if it exceeds 86% by weight, there is a difficulty in polymer formation due to the slow reaction rate.

The diisocyanate uses 1,6-hexamethylene diisocyanate (HDI), which is an aliphatic diisocyanate, and includes at least one aliphatic diisocyanate except for the HDI to improve transparency.

The aliphatic diisocyanate except for the HDI may have a linear or cyclic structure, 4,4-dicyclohexylmethanediisocyanate (H12MDI), 3-isocyanatomethyl-3,5,5 Tricyclohexyl isocyanate (3-isocyanatomethyl-3,5,5-trimethyl cyclohexylisocyanate (IPDI), 1,4 cyclohexyl diisocyanate (CHDI) and 2,2,4-trimethylhexamethylene di) At least one aliphatic diisocyanate selected from the group consisting of isocyanates (2,2,4-trimethylhexamethylene diisocyanate (TMDI), tetramethyl-xylenediisocyanate).

The content of the diisocyanate is 10 to 60% by weight based on the total composition of the thermoplastic polyurethane resin having excellent elastic recovery. If the content of the diisocyanate is less than 10% by weight, there is difficulty in polymerization due to reactivity problems. If the content of the diisocyanate is greater than 60% by weight, mechanical properties are greatly reduced due to phase separation of the soft segment and the hard segment.

In addition, the diisocyanate is preferably 80 to 99 mol% of 1,6-hexamethylene diisocyanate (HDI) with respect to the total aliphatic diisocyanate content, and preferably includes 1 to 20 mol% of aliphatic diisocyanates except for HDI. . More preferably, in the aliphatic or cycloaliphatic diisocyanate except for the HDI, tetramethylxylene diisocyanate is used in the same amount.

At this time, when the content of tetramethylxylene diisocyanate is less than 1 mol%, the improvement in transparency is insufficient, and when the content of the tetramethylxylene diisocyanate is 20 mol% or more, the elastic recovery power is reduced.

The chain extender of the present invention is a compound for extending the main chain of the polymer resin, and has a compound having 2 to 10 carbon atoms and a primary hydroxyl group or an amine group at both terminal groups. The chain extender ethylene glycol (ethylene glycol), diethylene glycol (dietylene glycol), propylene glycol (propylene glycol), dipropylene glycol (dipropylene glycol), 1,3-butanediol (1,3-butanediol), 1, 3 propanediol (1,3 propanediol), 1,4-butanediol (1,4-butanediol), 2-methylpentanediol, 2-methylpentanediol, 1,5-pentanediol (1,5-pentanediol), 3- 3-methyl pentane diol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol (1 Diols such as, 4-cyclohexane dimethane diol) and neophentylglycol, or 1,2-propylenediamine, 1,3-propylenediamine, 1,3-proylenediamine, isophoronediamine ), Diamines such as ethylenediamine, N-methylpropylene-1,3-diamine, N, N'-dimethylethylenetamine, etc. Or mixed can be used. The amount of the chain extender may be used in an amount of 3 to 30 wt% based on the total composition of the thermoplastic polyurethane resin. If the content of the chain extender is less than 3% by weight, there is a problem in that the molecular weight is not increased, thereby not expressing desirable physical properties, and when the content of the chain extender exceeds 30%, serious physical properties such as reduced elongation and reduced wear resistance may occur. have.

In addition, the content of the diisocyanate is preferably 0.9 mol to 1.10 mol, preferably 0.92 mol to 1.05 mol, and most preferably 0.93 mol to 1.02 mol, based on 1.0 mol of the chain extender and the total polyol polymer. In this case, the content of the diisocyanate is less than 0.9 mol relative to 1.0 mol of the chain extender and the polyol polymer as a whole, it is not preferable due to the deterioration of the physical properties, when the content of the diisocyanate exceeds 1.10 mol melt temperature is due to the occurrence of side reaction There is a problem such as excessively high and the gel (gel) occurs.

In addition, the present invention can produce a polyurethane resin using the composition. The high elastic aliphatic polyurethane resin manufacturing method with improved transparency of the present invention can be carried out by a conventional thermoplastic polyurethane resin manufacturing method, and is not particularly limited.

As described above, the polyurethane resin composition of the present invention uses aliphatic diisocyanate, in particular 1,6 hexamethylene diisocyanate (1,6-hexamethylene diisocyanate), without using conventional aromatic diisocyanate, and in particular, a chain extender alone Alternatively, by using a mixture, the initial modulus is high, the elastic recovery is fast, the yellowing resistance and the low temperature bendability are excellent, and at the same time, the transparency is improved by including 1-20 mol% of the tetrasulfoxylene diisocyanate, an aliphatic diisocyanate. Preferably, according to the present invention, even if the yellowing resistance measured by ASTM G53 method is more than 400 hours exposed to gray scale 4.0 or more, the result of repeated bending test measured by the method developed by using the ASTM D790 conventional aromatic thermoplastic polyurethane resin It is possible to provide a high elastic aliphatic thermoplastic polyurethane resin having advantages of low hysteresis, that is, fast elastic recovery. In addition, the transparency measured by ASTM D1033 can provide an improved aliphatic thermoplastic polyurethane resin compared to the case of using 1,6 hexamethylene diisocyanate alone.

 Hereinafter, examples of the present invention will be described. The following examples are only for illustrating the present invention and the present invention is not limited to the following examples.

(Examples 1 to 3)

Each compound was added to a continuous reaction extruder (Werner & Pfleiderer ZSK 58 twin screw extruder) in the content (unit: wt%) described in Table 1 below. The continuous reaction extruder is equipped with a raw material metering device and the dough block is 30% of the total screw (meaning that the whole screw length in the extruder is divided into three parts, which means that the mixing zone occupies about 30%). The rotation speed (rpm) was 250. The polymerization was carried out at a reaction temperature of 190 to 220 ℃ to prepare a resin.

 (Comparative Examples 1 to 3)

The thermoplastic polyurethane resin using the aromatic diisocyanate was used as the comparative example 1, and 1,6 hexamethylene diisocyanate which is an aliphatic diisocyanate alone or 4,4-dicyclohexyl methane isocyanate which is another type of aliphatic diisocyanate.

(4,4-dicyclohexylmethane diisocyanate; H12MDI) was used to obtain a thermoplastic resin in the same manner as in Examples 1 to 3.

Composition (wt%) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Polytetramethylene Ether Glycol Mw 1000 36.63 36.00 36.92 31.23 46.9 36.98 37.58 36.47 4,4'-methylenediphenyl-diisocyanate 52.63 Hexamethylene diisocyanate 40.22 37.44 37.63 42.75 42.30 31.10 Tetramethylxylene diisocyanate 3.08 6.84 6.38 0.71 13.59 4,4'-dicyclohexylmethane diisocyanate 42.2 Chain Extender (1,4-butanediol) 17.45 17.14 19.07 16.14 10.9 20.27 19.41 18.84 Chain Extender (3-methylpentanediol) 2.62 2.58

 (Property evaluation)

The physical properties of the Examples and Comparative Examples were measured by the following method, and the results are shown in Table 2 and FIG. 1.

1) Discoloration promoting test:

Temperature 50? Using Lamp A with Q-UV instrument UV fading was tested at 400 hours. As a result of the test, when evaluated in gray scale, it was 4.0 or more. The results indicate that when the composition of the present invention is used, UV stability is superior to that of general aromatic thermoplastic polyurethane resins as in Comparative Example 1. (Grey scale is divided into 5 steps from 0 to 5.0, and the higher the color change, the higher the number. Lowers)

2) Injection moldability evaluation was evaluated using the following injection machine. The injection machine is manufactured by Engel, Germany (Model: ES240 / 75P). The clamping force is 75 ton, screw diameter 35mm, screw stroke max. 160mm. In addition, the dimension of the cavity used for shaping | molding used 125 125 2 mm.

3) Hardness: The prepared low hardness thermoplastic polyurethane resin was injected and molded, and then measured for hardness based on ASTM D 2240 method.

4) Repeated Flexibility: Repeated flexibility was evaluated by referring to ASTM D790. This is a self-developed method for evaluating the elastic recovery rate, which will be described below with reference to FIG. 1.

Specimens of the same standard (width: 25mm, thickness: 3.2mm, length 130mm) of ASTM D790 were subjected to repeated experiments with 10 mm deformation and a constant stress of 0.4 to 1.0 Hz. After completing 100 repetitive bend tests, place on a flat bottom and measure the strained distance (L) from the bottom 10 minutes later. Flexural strain (%) is defined as the strained distance (L) / thickness (d) x 100% of the specimen. The smaller the bending strain, the better the elastic recovery, and the term of the bending strain used in the present invention indicates that measured by the test method.

5) Transparency: The transparency of the specimen was measured based on ASTM D1033.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Hardness, D 55 55 55 55 55 55 55 55 Injection Molding (Cyclic time (s)) 25 30 33 40 55 25 25 40 Flexural Strain (%) (L / d × 100) frequency 1Hz 20 25 24 100 110 15 15 60 UV stability (grey scale) 4.5 4.5 4.5 2.0 4.5 4.5 4.5 4.5 Light transmittance (%) 83 85 83 85 86 60 65 88

In Table 2, Examples 1 to 3 have a low bending strain (fast elastic recovery), excellent UV stability, and similar transparency compared to aromatic polyurethane resins having the same hardness (Comparative Example 1). In addition, Examples 1 to 3 had the same hardness and similar elastic recovery rate (lower bending strain) than Comparative Example 3 using 1,6 hexamethylene diisocyanate alone, and had similar transparency as Comparative Example 2 using aromatic diisocyanate. Could confirm. In addition, it was confirmed that the injection moldability and elastic recovery rate is superior to Comparative Example 2 using another aliphatic diisocyanate having the same hardness. When the tetramethylxylene diisocyanate is less than 1 mol%, light transmittance is not improved (Comparative Example 4), and when it is more than 20 mol%, it is found that the flexural strain is high and the elastic recovery rate is lowered (Comparative Example 5).

As described above, the present invention is excellent in yellowing resistance and excellent in injection moldability because of the high cooling solidification rate compared to the conventional aromatic thermoplastic polyurethane resin, and excellent in yellowing resistance and excellent in elastic recovery and transparency. Improved aliphatic thermoplastic polyurethane resin can be produced, because of this feature can be used in high-performance shoe parts, such as soccer shoes, basketball shoes, excellent low temperature flexibility can be applied to winter sports goods such as ski boots.

Claims (9)

a) 10 to 86% by weight of a polyol having a number average molecular weight of 650 to 6000, b) 10 to 60% by weight of diisocyanate containing 1,6-hexamethylene diisocyanate (hereinafter 'HDI') and at least one aliphatic diisocyanate except for HDI, c) an aliphatic thermoplastic having improved elasticity, characterized in that it contains 3 to 35% by weight of a chain extender having 2 to 10 carbon atoms, a bending strain is 30% or less, and transparency (ASTM D1033) is 80% or more. Polyurethane resin composition. The method of claim 1, wherein the polyol is one or more selected from the group consisting of polytetramethylene ether glycol, polycarbonate polyol, polybutyl adipate polyol, polyhexyl adipate and polycaprolactone polyol Aliphatic thermoplastic polyurethane resin composition with excellent elastic recovery. The aliphatic thermoplastic polyurethane resin composition having excellent elastic recovery as claimed in claim 1, wherein the polyol has a number average molecular weight of 1000 to 4000. The aliphatic diisocyanate except for HDI is 4,4-dicyclohexylmethanediisocyanate (H12MDI), 3-isocyanatomethyl-3,5,5-tri Cyclohexyl isocyanate (3-isocyanatomethyl-3,5,5-trimethyl cyclohexylisocyanate; IPDI), 1,4 cyclohexyl diisocyanate (CHDI), 2,2,4-trimethylhexamethylene diisocyanate ( 2,2,4-trimethylhexamethylene diisocyanate (TMDI), and tetramethyl-xylenediisocyanate (at least one selected from the group consisting of) an improved thermoplastic recovery excellent aliphatic thermoplastic polyurethane resin composition. The diisocyanate according to claim 1 or 4, wherein the diisocyanate is 80 to 99 mol% of 1,6-hexamethylene diisocyanate and 1 to 1 or more aliphatic diisocyanates other than the HDI based on the total aliphatic diisocyanate content. An excellent aliphatic thermoplastic polyurethane resin composition having improved elasticity, characterized in that it comprises 20 mol%. 5. The aliphatic thermoplastic polyurethane resin composition having excellent elastic recovery as claimed in claim 4, wherein the aliphatic diisocyanate except for HDI is tetramethylxylene diisocyanate. 7. The diisocyanate according to claim 1 or 6, wherein the diisocyanate is 80 to 99 mol% of 1,6-hexamethylene diisocyanate and 1 to 20 mol% of tetramethylxylene diisocyanate with respect to the total aliphatic diisocyanate content. Aliphatic thermoplastic polyurethane resin composition having excellent elastic recovery, characterized in that the transparency is improved. The method of claim 1, wherein the chain extender is ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methylpentanediol, 1,5-pentanediol, 3-methylpentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, neopentylglycol, 1,2-propylenediamine, 1, 3 or more selected from the group consisting of propylenediamine, isophoronediamine, ethylenediamine, N-methylpropylene-1,3-diamine, and N, N'-dimethylethylenediamine have improved transparency. Aliphatic polyurethane resin composition excellent in elastic recovery. According to claim 1, wherein the diisocyanate is an aliphatic polyurethane resin composition having excellent elasticity recovery, characterized in that it is contained in 0.9 to 1.10 mol relative to 1.0 mol of the chain extender and the total polyol polymer.

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