JPH0335053A - Thermoplastic polyurethane composition - Google Patents

Abstract

PURPOSE:To provide a composition having excellent heat resistance, injection moldability, cold resistance and mechanical performance by compounding a specific thermoplastic polyurethane with a small amount of a thermoplastic graft polymer. CONSTITUTION:The thermoplastic polyurethane composition comprises 92-99wt.% of a thermoplastic polyurethane and 8-1wt.% of a thermoplastic graft polymer, the polyurethane being prepared from (A) a polyesterdiol and/or a polycarbonatediol containing groups of formula I and II and/or III as essential structural units and having an average mol.wt. of 1500-3500, (B) a diisocyanate and (C) a chain-elongating agent so that the sum of the weights of the components B and C is 23-56% based on the sum of the weights o the components A, B and C, the graft polymer being prepared by graft-polymerizing an aromatic vinyl compound and a cyanized vinyl compound to an elastomer. The sum of the mol fractions of the groups of formulas II and III is >=10% based on the sum of the mol fractions of the groups of formulas I, II and III, and the sum of the mol fractions of the groups of formulas I and II is >=50% based on the sum of the mol fractions of the structural units originated from the diols.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a composition comprising a specific thermoplastic polyurethane blended with a small amount of a thermoplastic graft polymer.

The composition provided by the present invention has excellent heat resistance and injection moldability, as well as excellent cold resistance and mechanical performance. Because it has many features such as excellent abrasion resistance and oil resistance, it has attracted attention as an alternative material to rubber and plastic, and is used in large quantities in a wide range of applications as a molding material to which ordinary plastic molding methods can be applied. It is becoming more and more common. Thermoplastic polyurethanes are produced by mixing and polymerizing polymeric diols, diisocyanates, and chain extenders such as 1,4-butanediol.

Mold release properties (prevention of stickiness) during molding of thermoplastic polyurethane
In order to improve the temperature dependence of melt viscosity,
Resin 10-90 obtained by graft polymerizing an aromatic vinyl compound and a vinyl cyanide compound to a thermoplastic polytale tough 90-10 by weight and an ethylene-propylene rubber.
Attempts have been made to increase the weight and capacity of
17281 and Japanese Patent Publication No. 62-34265). In addition, in order to improve the molding processability of thermoplastic polyurethane, a terpolymer of acrylonitrile-styrene-butadiene or a terpolymer blend of 1 to 30 polyesters is added to the thermoplastic polyester polyester with a weight of 99 to 0. (Refer to I# Publication No. 54-7827) 0 [Problem to be solved by the invention] Conventional thermoplastic polyurethane has extremely poor heat resistance and requires a long injection molding cycle time. However, there are problems with injection moldability, such as poor properties and the occurrence of sink marks, and improvements in these aspects have been strongly discouraged.

A thermoplastic polyurethane composition containing a resin obtained by graft polymerizing an aromatic vinyl compound and a vinyl cyanide compound to the above-mentioned ethylene-propylene rubber contains a large amount of graft polymer. Although the adhesion is improved, there are problems in that the original characteristics of thermoplastic polyurethane, such as increased hardness, decreased elongation, and decreased bending resistance, are lost. Also,
The reality is that thermoplastic polyurethane compositions containing acrylonitrile-styrene-butadiene terpolymer or terpolymer blend polymers have not had their moldability improved to a satisfactory level without other problems. It is.

An object of the present invention is to provide a thermoplastic polyurethane composition having excellent heat resistance and injection moldability.

[Means to solve the problem]

According to the present invention, the above object consists of (A) 92 to 99% by weight of a thermoplastic polyurethane and (B) 8 to 1% by weight of a thermoplastic graft polymer, the thermoplastic polyurethane having (a) the following structure: Units (I) and (If) &/Mata II! (fil) as an essential structural unit and a polyester diol and/or polycarbonate diol having a number average molecular weight of 1,500 to 3,500, (b) a diisocyanate and (C) a chain extender. , and the sum of the weights of components (a), (b):Th and (C>) is 2
To provide a thermoplastic polyurethane composition, wherein the thermoplastic graft polymer is a polymer obtained by graft polymerizing an aromatic vinyl compound and a vinyl cyanide compound to a distoner. achieved by.

(I): -0-(CH2), -0-CH3 (I1): -0-CH2-CH-(CH2), -0
-CH3 (m): -0-(CH2)2-CH-(CH2)2
-0- In order for the composition of the present invention to exhibit high characteristics such as a high injection molding cycle speed, a small mold strain rate, and excellent heat resistance and cold resistance, it is necessary for the thermoplastic polyurethane to meet the above requirements. It is important to have a well-defined structure. In the case of a thermoplastic polyurethane composition that does not have this specified structure, the effects exhibited by the composition of the present invention are hardly observed.

The polyester diol and polycarbonate diol constituting the thermoplastic polyurethane of the present invention have a number average molecular weight of 1,500 to 1,500 as determined by the hydroxyl value and acid value.
It is extremely important that it be in the range of 3,500. The number average molecular weight is particularly preferably in the range of i,soo to 3.000. When the number average molecular weight is less than 1,500, there is almost no improvement in injection molding cycle speed, molding strain rate, and heat resistance, and when it exceeds 3,500, there is a large change in the melt viscosity applied during molding. , making stable molding difficult.

Polyester diols and polycarbonate diols have the above structural units (I), (■) and/or (I) as essential structural units in the molecule. Structural unit (
I) is derived from 1,9-nonanediol, structural unit (II) is derived from 2-methyl-1,8-octanediol, and structural unit (I[[) is derived from 3-methyl-1,
Derived from 5-hentanediol. Structural unit (II
)>The sum of the molar fractions of and (III) is the structural unit (+)
or III), and the sum of the mole fractions of structural units (I) and (II) is 10% or more with respect to the sum of the mole fractions of structural units derived from diols. 5
The composition of the present invention obtained from polyester diol and/or polycarbonate diol having a diameter of 0φ or more exhibits the above-mentioned effects to a higher degree. When the sum of the mole fractions of structural units (II) and (III) is less than 10 times the sum of the mole fractions of structural units (I) or III), the cold resistance and flexibility of the composition are affected. decreases and the sum of the mole fractions of the structural units (I) and (II) is less than 50% relative to the diol-derived structural unit, the heat resistance of the composition, the injection molding cycle speed, Either case is not favorable because the improvement effect applied to the molding strain rate etc. cannot be achieved with a sufficient level of the housing.

Examples of glycols used in combination in the production of polyester diol or polycarbonate diol in the present invention include ethylene glycol, 1°4-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,5-bentanediol, 1,6-hexanediol% 1+8-octanediol, 1.
Examples include 10-decanediol. These glycols can be used alone or in a mixture of two or more,
It is suitable to use less than 50 moles of the total diols used. The amount used is preferably 30 moles or less. Examples of dicarboxylic acids used in the production of polyester diols include succinic acid, adipic acid, azerai/acid, heptanosic acid, and the like, with adipic acid and azelaic acid being preferred. These dicarboxylic acids may be used alone or in mixtures of two or more.

The thermoplastic polyurethane used in the present invention is the sum of the weights of components (b) button and (C), that is, the weight of the sound segment component is the sum of the weights of components (a), ω) and (C). On the other hand, it is important that it is in the range of 23 to 56 degrees.

If the weight of the node segment component is less than 23%, the effect of improving the injection moldability and heat resistance of the composition is small, and if it exceeds 56% of the weight, the melt viscosity of the composition is The thermoplastic polyurethane of the present invention is obtained by melt polymerizing a polyester diol and/or a polycarbonate diol, a diisocyanate, and a chain extender. The diisocyanate used is an aliphatic, alicyclic or aromatic diisocyanate containing two isocyanate groups in the molecule, for example 4.4'
-diphenylmethane diisocyanate, p-phenylene diisocyanate, tolylene diisocyanate), 1.5
-naphthylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, inphorone diisocyanate), 4,4'-dicyclohexylmethane diisocyanate, and the like.

As the diisocyanate, 4,4'-diphenylmethane diincyanate is particularly preferred. The chain extender used is a chain extender commonly used in the polyurethane industry, i.e., one containing at least two hydrogen atoms capable of reacting with incyanate.
Low molecular weight compounds having a molecular weight of 400 or less can be used, such as ethylene glycol, propylene gelicol, 1,4-nonanediol, neopentyl glycol, 1゜6-hexanediol, 3-methyl-1,5
-hentanediol, 1.4-cyclohexanediol, 1.4-bis(β-hydroxyethoxy)benzene,
Diols such as bis(β-hydroxyethyl) terephthalate and xylylene glycol; diamines such as ethylene diamine, propylene diamine, xylylene diamine, inphorone diamine, piperazine, phenylene diamine, and tolylene diamine; hydrazine; adipic acid dihydrazide, isophthalic acid dihydrazide Examples include hydrazides such as. Most preferably, 1,4-butanediol or 1,4-bis(β-hydroxyethoxy)benzene is used as the chain extender. These compounds may be used alone or in combination of two or more.

The polymerization conditions are those employed in known urethane production reactions, and the polymerization temperature is preferably in the range of 200 to 240°C.

By keeping the polymerization temperature at 200°C or higher, a polyurethane with good moldability can be obtained, and by keeping the polymerization temperature at 240°C or lower, a polyurethane with increased heat resistance can be obtained.

As the polymerization method, it is particularly preferable to employ a continuous melt polymerization method using a multi-screw extruder.

In the composition of the present invention, a thermoplastic polyurethane having the above-specified structure is combined with an aromatic vinyl compound and a vinyl cyanide compound (graft monomer) to a thermoplastic polyurethane (grafting base) to obtain a thermoplastic polyurethane having the above-specified structure. Blending the plastic graft polymer in a specific ratio is an important requirement for achieving the above object of the present invention. In the present invention, it is necessary to allocate 92 to 99 parts by weight of thermoplastic polyester resin and 8 to 1 part by weight of thermoplastic graft polymer. If the proportion of the thermoplastic graft polymer is less than 1 weight, the effect of the present invention will hardly be exhibited, and if it exceeds 8 weight, the hardness of the composition will increase and the elongation will decrease. do. Therefore, when comparing a composition having an increased hardness with a blending ratio of thermoplastic graft polymer of more than 8 times and a composition of the present invention having the same hardness, the former composition has a polyurethane The hard segment content of the latter composition is lower than that of the latter composition, and the heat resistance and bending resistance are lower than that of the latter composition, and the original characteristics of thermoplastic polyurethane are impaired, making it difficult to use. becomes limited.

The above-mentioned graft substrate Nidistomer has a temperature of -30°C.
It is preferable to use those with lower second-order transition temperatures. Examples of the aromatic vinyl compound used as the graft monomer include styrene, α-methylstyrene, alkyl-substituted styrene, and styrene substituted with halogen. In particular, it is preferable to use styrene.
Examples of vinyl cyanide compounds used include acrylonitrile and methacrylonitrile. Particular preference is given to using acrylonitrile.

Examples of the thermoplastic graft polymer used in the present invention include a resin obtained by graft polymerizing an aromatic vinyl compound and a vinyl cyanide compound to an ethylene-propylene comb (hereinafter referred to as ABS resin). It will be done. As the ethylene-propylene rubber, ethylene-propylene copolymer rubber and ethylene-propylene-diene copolymer rubber are used. The weight ratio of ethylene and propylene is preferably in the range of 9:1 to 2:8.

Further, as the diene monomer, norbornenes such as alkenylnorbornene, cyclic dienes such as dicyclope7p diene, aliphatic dienes such as hexadiene, etc. are used. The diene monomers may be used alone or in combination of two or more.

The weight ratio of ethylene-propylene rubber to the vinyl compound used for graft polymerization, such as an aromatic vinyl compound or vinyl cyanide compound, is preferably in the range of 5:95 to so:soo! *The range of 10:90 to 40:60 is preferable. ABS resins are produced by bulk polymerization, emulsion polymerization, solution polymerization, bulk-suspension polymerization, suspension polymerization, emulsion-suspension polymerization, and the like.

Examples of the thermoplastic graft polymer used in the present invention include a copolymer obtained by emulsion polymerization of acrylonitrile and styrene graft monomers added to a butadiene polymer latex, and an acrylonitrile-butadiene copolymer and styrene copolymer. - Acrylonitrile copolymer and the like (hereinafter, these are collectively referred to as ABS resins). As the butadiene polymer latex, for example, polybutadiene latex, acrylonitrile-butadiene copolymer latex, stereo/butadiene copolymer latex, etc. are used. The ratio of each component above is 1 bag of butane to 50 bags by weight, 20 to 85 bags of steref
After pre-mixing heavyweight, heavy-duty thermoplastic polyurethane and thermoplastic graft polymer at a predetermined ratio using a vertical or horizontal mixer commonly used for mixing resin materials, It is manufactured by heating and kneading in a batch type or continuous type using an extruder, mixing roll, Banbury mixer, etc. Additives such as stabilizers, plasticizers, montanic acid waxes, lubricants such as aliphatic amide, fillers, antistatic agents, pigments, etc. to further improve light resistance and heat resistance during mixing may be added without impairing the effects of the present invention. It is possible to add in small amounts.

The thermoplastic polyurethane composition of the present invention has particularly excellent moldability including injection moldability, and heat resistance.
It can be easily molded using commonly used injection molding machines, extrusion molding machines, blow molding machines, calenders, etc. The thermoplastic polyurethane composition of the present invention has high molding dimensional accuracy, and has excellent heat resistance, cold resistance, oil resistance, abrasion resistance, toughness, and mechanical performance, so it can be used in sheets, films, rolls, etc. , gear, solid tires, snow tires,
Materials for snow chains, belts, watch bands, hoses, tubes, backing materials, anti-vibration materials, shoe soles, sports shoes, and various other laminate products.

Used in mechanical parts, automobile parts, sporting goods, elastic fibers, etc. Furthermore, the thermoplastic polyurethane composition of the present invention can be dissolved in a solvent and used for artificial leather, coating agents, fiber treatment agents, adhesives, binder paints, and the like.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples in any way. Among the reference examples, the number average molecular weight was determined according to the method below.

In addition, in Examples and Comparative Examples, injection moldability (molding cycle time), heat resistance,
Cold resistance, bending resistance, and hardness were evaluated according to the following method.The hard segment content of thermoplastic polyurethane means the weight percentage of segments based on diisocyanate and chain extender in the thermoplastic polyurethane. do.

(I) Number average molecular weight: 0 determined from the hydroxyl value and acid value of polyester diol or polycarbonate diol Heat resistance and cold resistance: Test made from a 500μ thick polyurethane composition film obtained by extrusion molding For the piece, using a dynamic viscoelasticity measuring device [DVE Rheospectra manufactured by Rheology], the storage elastic modulus E'(I0(I) (d)'ne/aJ at 100°C
) was measured, and the heat resistance was evaluated using E' (I0(b). The larger this value is, the better the heat resistance is. In addition, the same behavior was measured for test pieces made from polyurethane composition films of the same thickness. Tα (peak temperature of E", 11 Hz) was measured by temperature dispersion using a viscoelasticity measuring device, and cold resistance was evaluated based on this.

(8) Injection moldability: Injection molding is performed while changing the molding cycle time (quantum cooling time during injection), and the molding cycle time at which shrinkage and deformation do not occur in the obtained molded product is measured. evaluated.

(4) Flexibility: 500μ (thickness) x 70w x 45m
The bending resistance of the test piece was tested at -20℃ using a bending tester according to the method specified in JIS K-6545. evaluated.

(5) Hardness: Shore hardness was evaluated by humans according to the method specified in JIS K-6301.

Reference Example 1 Production of polyester diol Mixture of 2-methyl-1,8-octanediol and 1,9-nonanediol (molar ratio = 35:65) 1.600
? and adipic acid 1,4609 were charged into a reactor, and an esterification reaction was carried out while passing nitrogen gas into the system under normal pressure and distilling condensed water out of the system at a temperature of about 220°C.

When the acid value of the polyester became 0.3 or less, the degree of vacuum was gradually increased using a vacuum pump to complete the reaction. The polyester diol thus obtained had a hydroxyl value of 56 and an acid value of 0.12. It had a number average molecular weight of 2,000.

Reference Examples 2 to 7 Manufacture of polyester diol The esterification reaction was carried out in the same manner as in Reference Example 1, except that dicarboxylic acids giving the dicarboxylic acid components and diols giving the diol components shown in Table 1 were used, respectively.
Polyester diols shown in Table 1 were obtained.

Reference Example 8 Production of polycarpo-diol Mixture of 2-methyl-1,8-octanediol and 1.9-nona/diol (molar ratio = 35:65) under nitrogen flow
) 1,730f and diphenyl carbonate 2,1
409 was charged into a reactor and heated to 200°C,
The generated phenol was distilled out of the system.

After gradually raising the temperature to 210-220°C and distilling most of the phenol out of the system, the pressure in the system was reduced to 6-10 μHg, and the remaining phenol was completely removed from the system at the same temperature under this reduced pressure. The polycarbonate diol thus obtained had a hydroxyl value of 56.0, a number average molecular weight of 2,
It had 000.

Reference Examples 9 and 10 The reaction was carried out in the same manner as in Reference Example 8, except that diols giving the diol components shown in Table 1 were used, and ethylene carbonate was used instead of diphenyl carbonate, to produce polycarbonate diols shown in Table 1, respectively. Obtained.

For the polyester diols obtained in Reference Examples 1 to 7 and the polycarbonate diols obtained in Reference Examples 8 to 10, the diol component buttons and their proportions, the dicarboxylic acid component of the polyester diol, and the number average molecular weight are summarized in Table 1.
Shown below. In Table 1, the diol component and dicarboxylic acid component are represented by the diol and dicarboxylic acid indicated by the following abbreviations, respectively.

ND: MOD: MPD: HD: NPG: EG: AD: 1,9-nonanediol 2-methyl-1,8-octanediol 3-methyl-1
, 5-bentanediol 1,6-hexanesiol neopentyl glycol ethylene glycol adipic acid Below margin Example 1 Polyurethane acid product production and performance evaluation Polyester diol (A) and 1,4-butanediol (hereinafter referred to as
This is abbreviated as BD) at a molar ratio of 1:4.
4,4'-diphenylmethane diisocyanate (hereinafter referred to as MDI) heated to 50°C and fused to this.
) was continuously charged into a twin-screw extruder rotating in the same direction using a metering pump in an amount such that the molar ratio of polyester diol (A) to MDI to BD was 1:5:4, and continuous melt polymerization was carried out. The reaction was carried out. When the interior of this twin-screw extruder was divided into three zones: a front section, a middle section, and a rear section, the temperature (polymerization temperature) of the middle section, which was the highest temperature, was set at 230°C. The polyurethane produced was continuously extruded into water in the form of a strand, and then formed into pellets using a pelletizer.

To 100 parts of the obtained polyurethane pellets, 3 parts of ABS resin (manufactured by Japan Synthetic Rubber ■, AES 110) and 0.5 parts of montan acid wax (Hoechst wax 0P) were added to 100 parts of the obtained polyurethane pellets using a 25wφ extruder (cylinder temperature 200°C, die temperature 180°C). ) and pelletized. Then,
The pellets of the obtained polyurethane composition were put into an injection molding machine (
Using Nissei Jushi Kogyo ■, FS80S12ASE, cylinder temperature 175-200°C, nozzle temperature 200°C, mold temperature 30°C, injection pressure 100 kg/cjG),
Injection molding was performed by changing the molding cycle time (quantum cooling time during injection), and the molded product (I50wX 25+wX 6txxx
)It was created.

The molding cycle time at which sink marks and deformation did not occur was measured for the obtained molded product. Further, pellets of the above polyurethane composition were molded according to the above method, and the heat resistance, cold resistance, bending resistance, and hardness were evaluated. The evaluation results are shown in Table 2.

Comparative Example 1 Production Button and Performance Evaluation of Polyurethane Composition Pellets of polyurethane composition were obtained by the same operation as in Example 1 except that ABS resin was not added, and the pellets were injection molded in the same manner to obtain a molded product. Created. The same evaluation as in Example 1 was conducted, and the evaluation results are shown in Table 2.

Examples 2 to 7 and Comparative Examples 2 to 13 Production and performance evaluation of polyurethane compositions Example IK&
The reaction button was prepared in the same manner except that the polyester diol or polycarbonate diol shown in Table 2 was used instead of polyester diol (A), and the polyester diol or polycarbonate diol and the MDI button and BD were charged in the molar ratio shown in Table 2. Polyurethane pellets were obtained by performing the following operations. To these pellets, in the same manner as in Example 1, ABS resin (manufactured by Japan Synthetic Rubber #, AESIIO) or ABS resin (manufactured by Nippon Synthetic Rubber ■, ABSIO) was added in a predetermined proportion, or a case was mixed. Pellets of the polyurethane composition were obtained without the addition of polyurethane, and these pellets were injection molded in the same manner to produce molded articles. Similar evaluations were made for Example 1, and the evaluation results are shown in Table 2.

Example 8 Production and Performance Evaluation of Polyurethane Composition Polyurethane pellets were obtained by carrying out the reaction and operation in the same manner as in Example 1 except that p-phenyl diisocyanate was used instead of MDI. Pellets of the polyurethane composition were obtained by performing the same operations as in Example 1.1. This pellet was injection molded in the same manner to produce a molded product. The same evaluation as in Example 1 was carried out, and the evaluation results are shown in Table 2. Example 9 Production and performance evaluation of polyurethane composition In Example 1, 1,4-bis(hydroxyethoxy) was substituted for BD.
Polyurethane pellets were obtained by performing the reaction and operation in the same manner except that benzene was used. A polyurethane composition was obtained from this pellet by performing the same operations as in Example 1, and this pellet was injection molded in the same manner to produce a molded article. The same evaluation as in Example 1 was performed, and the evaluation results are shown in Table 2.

[Effects of the Invention] As is clear from Table 2 above, the thermoplastic polyurethane composition provided by the present invention is excellent in all of heat resistance, injection moldability, cold resistance, bending resistance, and hardness. The composition also has excellent oil resistance, abrasion resistance, toughness, and mechanical performance.

Claims (1)

[Scope of Claims] 1. Consists of (A) 92 to 99% by weight of a thermoplastic polyurethane and (B) 8 to 1% by weight of a thermoplastic graft polymer, wherein the thermoplastic polyurethane comprises (a) the following structural unit (I ) and (II) and/or (III) as essential structural units and has a number average molecular weight of 1,500 to 3,5
00 polyester diol and/or polycarbonate diol and (b) diisocyanate and (c)
and a chain extender, and the sum of the weights of components (b) and (c) is in the range of 23 to 56% of the sum of the weights of components (a), (b) and (c), A thermoplastic polyurethane composition, wherein the thermoplastic graft polymer is a polymer obtained by graft polymerizing an aromatic vinyl compound and a vinyl cyanide compound to an elastomer. (I): -O-(CH_2)_9-O- (II): ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (III): ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ 2. In polyester diol and polycarbonate diol The sum of the mole fractions of structural units (II) and (III) is 10% or more of the sum of the mole fractions of structural units (I) to (III), and the structural units (I) and (II) 2. The thermoplastic polyurethane composition according to claim 1, wherein the sum of the mole fractions of the diol-derived structural units is 50% or more of the sum of the mole fractions of the diol-derived structural units.