JPH07310009A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition useful as a material for the bottom of a ski boot or a golf shoe, having low specific gravity, excellent injection moldability, freeze resistance and flexing resistance. CONSTITUTION:This resin composition comprises (A) a specific thermoplastic polyurethane and a thermoplastic graft polymer (ABS or AES) in a weight ratio of 90/10-50/50. The thermoplastic polyurethane is obtained by reacting a specific polyester diol with an organic diisocyanate and a chain extender and has <=3wt.% of nitrogen atom content. The specific polyester diol has 1,500-4,500 number-average molecular weight and the ratio of a mol fraction of a structural unit of the formula O-(CH2)6-O/a structural unit of the formula O-CH2-CH(CH3)-(CH2)6-O of 100/0 to 50/50 in the molecule and the ratio of a mol fraction of a structural unit of the formula C(=O)-(CH2)n-C(=O) ((n) is 4-12)/a structural unit of the formula C(=O)-Ar-C(=O) of 100/0 to 50/50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition prepared by blending a specific thermoplastic resin with a specific thermoplastic resin. INDUSTRIAL APPLICABILITY The resin composition provided by the present invention has a low specific gravity, excellent injection moldability, and excellent cold resistance and bending resistance, and thus is particularly useful as a material for ski boots, golf shoe soles, and the like. .

[0002]

2. Description of the Related Art Conventionally, thermoplastic polyurethane (hereinafter sometimes abbreviated as TPU) has a high elastic modulus and has many features such as excellent wear resistance and oil resistance. It has been drawing attention as a substitute material for plastics, and since it can be applied with an ordinary plastic molding method, it has come to be used in large amounts in a wide range of applications as a molding material. TPU is produced by polymerizing chain extenders such as polymeric diols, diisocyanates and 1,4-butanediol.
Polyester-based polyurethane, polyether-based polyurethane, polycarbonate-based polyurethane and the like are known as TPU, and they are used in various applications by taking advantage of their respective characteristics. Among them, polyester-based polyurethane is generally known to have excellent mechanical performance.

However, since TPU has a stronger adhesiveness than other thermoplastic resins, the mold release during injection molding is poor, and the molded articles are apt to adhere to each other, resulting in poor injection moldability. Further, there is a drawback that it is not easy to obtain a molded product with high accuracy because the molding shrinkage rate in injection molding is large and it greatly changes depending on various conditions such as molding conditions and mold shape. As an attempt to improve releasability or prevent sticking during TPU molding, polyether-based polyurethane or 1,4 produced by using polytetramethylene glycol as a polymer diol
-A polyester-based polyurethane produced by using a polyester diol obtained by reacting butanediol, ethylene glycol and dicarboxylic acid as a polymer diol, a resin composition containing an AES resin has been proposed (Japanese Patent Publication No. No. 60-17281 and Japanese Patent Publication No. 62-34265).

[0004]

As described above, the TPU is
Has a large injection molding shrinkage ratio, requires a long injection molding cycle, and is inferior in productivity of molded products. Further, in recent years, in fields such as ski boots and golf shoe soles, there is an increasing demand for resin materials that are not only excellent in injection moldability, but also light in weight and excellent in cold resistance and bending resistance. The present inventor manufactured and evaluated the above known resin composition of TPU and AES of polyether type or polyester type having 1,4-butanediol and ethylene glycol as a glycol component, and the obtained resin composition was obtained. Has a large specific gravity and insufficient flex resistance, and it has been found that the injection moldability also needs to be further improved. Therefore, an object of the present invention is to provide a resin composition having a low specific gravity, excellent cold resistance and bending resistance, and excellent injection moldability.

[0005]

According to the present invention, the above-mentioned objects are mainly obtained by graft-polymerizing an aromatic vinyl compound and a vinyl cyanide compound on a thermoplastic polyurethane (A) and an elastomer. A resin composition comprising a polymer (B) and having a weight ratio of (A) / (B) within the range of 90/10 to 50/50, wherein the thermoplastic polyurethane (A) is represented by the following formula ( Structural unit (1) represented by I) and the following general formula (II
The structural unit (3) represented by I) is the main structural unit,
The molar ratio of the structural unit (1) and the structural unit (2) represented by the following formula (II) is (1) / (2), which is 100/0.
Within the range of 50/50, and the molar ratio of the structural unit (3) to the structural unit (4) represented by the following general formula (IV) is (3) / (4): 100/0 A thermoplastic polyurethane having a nitrogen atom content of 3% by weight or less, which is obtained by reacting a polyester diol having a number average molecular weight of 1500 to 4500 in the range of 50/50, an organic diisocyanate and a chain extender. It is achieved by providing a resin composition characterized by:

[0006]

[Chemical 5]

[0007]

[Chemical 6]

[0008]

[Chemical 7]

[0009]

[Chemical 8]

(In the formula, n represents an integer of 4 to 12, and Ar
Represents a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms. )

In the resin composition of the present invention, in order to develop all of the characteristics of low specific gravity, small injection molding strain rate, and excellent cold resistance and flex resistance in a well-balanced and highly advanced manner, TPU is required. It is important that has the structure specified above.

It is important that the number average molecular weight of the polyester diol which is a raw material for producing the thermoplastic polyurethane (A) (hereinafter sometimes abbreviated as TPU (A)) in the present invention is in the range of 1500 to 4500. is there.
When the number average molecular weight is less than 1500, the injection molding strain rate of the obtained resin composition is large. The number average molecular weight is 4
Since polyester diols exceeding 500 have high crystallinity, TPU and resin compositions using the same cannot secure flexibility, and have poor cold resistance and elastic recovery. Furthermore, if it exceeds 4500, TP
The productivity of U decreases and the melt viscosity of TPU is high, so that the stability of the resin composition during molding is also decreased. It is preferable that the number average molecular weight of the polyester diol is within the range of 1800 to 4000, because it is particularly excellent in all of the various properties such as injection molding strain rate, flexibility, cold resistance, and elastic recovery.

The polyester diol has structural units (1) and (3) as main structural units, and structural units (2) and // as additional structural units.
Alternatively, it may have the structural unit (4). The structural unit (1) and the structural unit (2) are diol-derived structural units, and the structural unit (3) and the structural unit (4) are dicarboxylic acid-derived structural units. 1,9-nonanediol is mentioned as a typical compound which gives structural unit (1), and 2-methyl-1,8-octanediol is mentioned as a typical compound which gives structural unit (2).
Examples of the linear aliphatic dicarboxylic acid having 6 to 14 carbon atoms which gives the structural unit (3) include adipic acid, azelaic acid, sebacic acid and dodecanedioic acid, and adipic acid and azelaic acid are particularly preferable. Structural unit (4)
Having 6 to 12 carbon atoms represented by Ar in the general formula (IV)
Examples of the divalent aromatic hydrocarbon group include a phenylene group, a methylphenylene group, and a naphthylene group. Examples of the aromatic dicarboxylic acid having 8 to 14 carbon atoms which gives the structural unit (4) include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid and 2,6-naphthalene. Examples include dicarboxylic acids, with isophthalic acid and terephthalic acid being particularly preferred.

The structural unit (1) is the main component of the diol-derived structural unit constituting the polyester diol,
When the molar fraction based on the structural unit derived from diol is preferably 60 mol% or more, it becomes possible to obtain a resin composition excellent in cold resistance, moldability and heat resistance. Further, the structural unit (3) is the main component of the structural unit derived from dicarboxylic acid constituting the polyester diol, and preferably the molar fraction based on the structural unit derived from dicarboxylic acid is 70 mol% or more.
It is possible to obtain a resin composition having excellent moldability and cold resistance and having a low specific gravity. The ratio [(1) / (2)] of the molar fraction of the structural unit (1) and the structural unit (2) in the polyester diol is in the range of 100/0 to 50/50. When the mole fraction of the structural unit (2) is larger than that of the structural unit (1), the resulting resin composition is inferior in heat resistance and cold resistance.

Structural unit (3) in polyester diol
Ratio of the molar fraction of the structural unit (4) [(3) /
(4)] is in the range of 100/0 to 50/50.
When the ratio of the mole fractions of (3) / (4) is smaller than 50/50, the injection moldability and cold resistance of the resin composition are poor.
Molar fraction of structural unit (1) in polyester diol (based on structural unit derived from diol) and structural unit (3)
The total of the mole fraction (based on the structural unit derived from dicarboxylic acid) in the range of 130 to 180 mol% is low specific gravity and is excellent in moldability, cold resistance and bending resistance. It is preferable because the feature (1) is particularly effectively expressed.

The method for producing the polyester diol in the present invention is not particularly limited. For example, a polyester diol having a desired structural unit and a molecular weight is appropriately produced by performing an esterification reaction or a transesterification reaction using a desired diol and a dicarboxylic acid (or an esterified product thereof) according to a known production method. You can

Examples of the organic diisocyanate used in the present invention include 4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate,
Molecular weight of 1,5-naphthylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, etc. 50
Diisocyanates of 0 or less are preferred. Among these, 4,4'-diphenylmethane diisocyanate is particularly preferable. As the chain extender, ethylene glycol, propylene glycol, 1,4-butanediol,
Neopentyl glycol, 1,6-hexanediol,
Molecular weight of 3-methyl-1,5-pentanediol, 1,4-bis (β-hydroxyethoxy) benzene, etc. 40
It is preferable to use diols of 0 or less. Among these, it is particularly preferable to use 1,4-butanediol. The organic diisocyanate and the chain extender may be used alone or in combination of two or more kinds.

The nitrogen atom content of the thermoplastic polyurethane (A) used in the present invention is 3% by weight or less. If the polyurethane content exceeds 3% by weight, it is difficult to obtain a resin composition having a low specific gravity. On the other hand, if the polyurethane content exceeds 3% by weight, the melt viscosity of the polyurethane changes greatly over time, and molding defects are likely to occur. In addition, the nitrogen atom content is 1.4- because the productivity of the thermoplastic polyurethane is excellent.
It is preferably within the range of 3% by weight.

The thermoplastic polyurethane (A) used in the present invention comprises the polyester diol, the organic diisocyanate and the chain extender, the mole number of the isocyanate group of the organic diisocyanate, the polyester diol and the chain extender. It is preferably obtained by reacting the agent at a ratio such that the ratio with the number of moles of hydroxyl groups (the number of moles of isocyanate group / the number of moles of hydroxyl group) is in the range of 0.98 to 1.08. TP obtained by setting the ratio of the number of moles of isocyanate group / the number of moles of hydroxyl group to 0.98 or more.
U, and eventually, the various physical properties of the resin composition can be maintained at a high level. On the other hand, by setting this ratio to 1.08 or less, generation of partial cross-linking between polyurethane molecular chains during storage of the obtained TPU or resin composition is suppressed, and when stored in the form of pellets or the like. Since the storage stability becomes good, problems such as defective molding can be less likely to occur.

As a method for polymerizing a polyester diol, an organic diisocyanate and a chain extender to produce a thermoplastic polyurethane, a known urethanization reaction technique can be adopted. Among them, it is preferable to carry out melt polymerization in the substantial absence of a solvent, and particularly preferable is a continuous melt polymerization method using a multi-screw extruder. Polyurethanes obtained by continuous melt polymerization generally have a temperature of 80 to 130 ° C.
It is superior in strength to the polyurethane obtained by solid-state polymerization. The melt polymerization temperature is not particularly limited, but is 180
It is preferably in the range of to 260 ° C., and within that range, 2
It is more preferable to keep the temperature at 40 ° C. or lower. 240 ° C
By keeping the content below, it is possible to obtain a high-quality polyurethane excellent in heat resistance and moldability.

In the resin composition of the present invention, a thermoplastic resin obtained by graft-polymerizing a graft monomer composed of an aromatic vinyl compound and a vinyl cyanide compound on a graft substrate composed of an elastomer together with the above-mentioned thermoplastic polyurethane (A). It is also important to contain the graft polymer (B) in a specific ratio. In the present invention, the weight ratio of thermoplastic polyurethane (A) / thermoplastic graft polymer (B) is in the range of 90/10 to 50/50. A resin composition having a weight ratio of more than 90/10 (too little thermoplastic graft polymer (B)) has large specific gravity and injection molding strain. On the other hand, this weight ratio is 50 /
When it is less than 50 (when the thermoplastic graft polymer (B) is too much), the hardness of the resin composition becomes too high,
The original properties such as bending resistance and flexibility of TPU are significantly impaired.

As the above-mentioned elastomer serving as the graft substrate, one having a second-order transition temperature lower than -30 ° C is preferable. As the aromatic vinyl compound which is one of the graft monomers, for example, styrene, α-methylstyrene, alkyl-substituted styrene, halogen-substituted styrene and the like are used, and styrene is particularly preferable. As the vinyl cyanide compound, for example, acrylonitrile, methacrylonitrile, etc. are used,
It is particularly preferable to use acrylonitrile.

The thermoplastic graft polymer used in the present invention is, for example, a copolymer obtained by adding both graft monomers of acrylonitrile and styrene to a latex of a butadiene-based polymer and emulsion-polymerizing it (hereinafter referred to as ABS resin). Abbreviated).
As the butadiene-based polymer latex, polybutadiene latex, acrylonitrile-butadiene copolymer latex, styrene-butadiene copolymer latex and the like are used. The proportion of each of the above components in the ABS resin is generally 5 to 50% by weight of butadiene, 20 to 85% by weight of styrene, 5 to 40% by weight of acrylonitrile.
Is.

Another example of the thermoplastic graft polymer used in the present invention is a resin (hereinafter referred to as AES) obtained by graft-polymerizing an ethylene-propylene rubber with an aromatic vinyl compound and a vinyl cyanide compound. (Abbreviated as resin). As the ethylene-propylene rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, etc. are used. Weight ratio of ethylene and propylene (ethylene:
Propylene) is preferably in the range of 9: 1 to 2: 8. Further, as the diene monomer, norbornenes such as alkenyl norbornene, cyclic dienes such as dicyclopentadiene, and aliphatic dienes such as hexadiene are used. The diene monomers may be used alone or in combination of two or more. The weight ratio of ethylene-propylene rubber to graft monomer such as aromatic vinyl compound and vinyl cyanide compound (ethylene-propylene rubber: graft monomer) is generally 5:95 to 50:
A range of 50 is suitable, and a range of 10:90 to 40:60 is preferable. AES resin is bulk polymerization method, emulsion polymerization method,
It is produced by a solution polymerization method, a bulk-suspension polymerization method, or the like.

The resin composition of the present invention can be produced, for example, by mixing the above-mentioned thermoplastic polyurethane (A) and thermoplastic graft polymer (B) by a desired method. For example, a thermoplastic polyurethane (A) and a thermoplastic graft polymer (B) are prepared by using a vertical or horizontal mixer which is usually used for mixing resin materials.
And (2) are premixed at a predetermined ratio, and then melt-kneaded under heating in a batch or continuous manner using a single-screw or twin-screw extruder, a mixing roll, a Banbury mixer, etc. to give the resin composition of the present invention. The thing is manufactured. During mixing, a stabilizer for improving light resistance, heat resistance, etc.,
Additives such as a plasticizer, a lubricant such as montanic acid wax and a fatty acid amide, a filler, an antistatic agent, and a pigment can be added in an amount that does not impair the effects of the present invention.

The resin composition of the present invention has excellent injection moldability, low specific gravity, and excellent cold resistance and flex resistance, and is therefore useful as a material for ski boots, golf shoe soles and the like.

[0027]

The present invention will be described below with reference to examples, but the present invention is not limited to these examples. Incidentally, the number average molecular weight of the polyester diol in the following reference examples, and the nitrogen atom content of the resin in the following examples and comparative examples, the specific gravity of the resin and the resin composition, cold resistance, flex resistance, injection molding strain and hardness. Is
Each was evaluated by the following methods.

(A) Number average molecular weight It was determined from the hydroxyl value and acid value of the polyester diol.

(B) Nitrogen atom content The content was determined by elemental analysis of polyurethane (type 2400-2 manufactured by Perkin Elmer Co., Ltd. was used as an elemental analyzer).

(C) Specific gravity Injection molding machine (FS80S12ASE manufactured by Nissei Plastic Industry Co., Ltd.)
JIS K for a disk-shaped product (diameter 120 mm, thickness 2 mm) molded under the conditions of a cylinder temperature of 175 to 200 ° C., a nozzle temperature of 200 ° C., and a mold temperature of 30 ° C.
It measured based on -7112.

(D) Cold resistance A dynamic viscoelasticity measuring device (DVE Rheospectler, manufactured by Rheology Co., Ltd.) was used for a test piece prepared from a disk-shaped material of the same kind as that used in the measurement of the specific gravity. The dynamic viscoelasticity was measured at a frequency of 11 Hz, and the temperature (Tα) at which the dynamic loss elastic modulus E ″ reached a peak was determined, and thereby the cold resistance was evaluated.

(E) Flex resistance Using a sheet (thickness 1 mm) formed by an extruder (cylinder temperature of 165 to 200 ° C.), JIS K-654 is used.
According to 5, the bending resistance at -20 ° C was examined by a bending resistance tester. The flex resistance was evaluated by the number of flexes until a crack was visually observed in the test piece.

(F) Injection Molding Strain The degree of deformation of the same kind of disc-shaped product as used in the above-mentioned measurement of the specific gravity with respect to the mold was expressed by the following mathematical formula.

[0034]

[Equation 1]

(G) Hardness A shore hardness A was determined according to JIS K-6301 using a disk-shaped material of the same kind as that used in the measurement of the specific gravity.

Reference Example 1 (Production of Polyester Diol A) 1600 g of a mixture of 2-methyl-1,8-octanediol and 1,9-nonanediol (molar ratio = 35: 65)
Then, 1460 g of adipic acid was charged into the reactor, and an esterification reaction was performed at a temperature of about 220 ° C. while distilling generated water out of the system while passing nitrogen gas through the system under normal pressure. When the acid value of the polyester became 0.3 or less, the degree of vacuum was gradually raised by a vacuum pump to complete the reaction. The polyester diol thus obtained is
It had a hydroxyl value of 56, an acid value of 0.12 and a number average molecular weight of 2,000. Table 1 shows the composition of structural units of this polyester diol (hereinafter referred to as polyester diol A).

[Reference Examples 2 to 4] (Production of polyester diols B, C and D) The same as in Reference Example 1 except that dicarboxylic acids and diols giving the predetermined dicarboxylic acid components and diol components shown in Table 1 were used. The esterification reaction was carried out to obtain polyester diols (hereinafter referred to as polyester diols B, C and D) having the structural units and number average molecular weights shown in Table 1, respectively.

[0038]

[Table 1]

In Table 1 above, the diol component and the dicarboxylic acid component are represented by the diol and dicarboxylic acid shown by the abbreviations in Table 2 below, which give them respectively.

[0040]

[Table 2]

[Example 1] (Production of resin composition) The molar ratio of polyester diol (A) and 1,4-butane diol (hereinafter abbreviated as BD) was 1: 1.
The mixture of 9 was heated to 30 ° C., and this and 4,4′-diphenylmethane diisocyanate (hereinafter, abbreviated as MDI) heated and melted at 50 ° C. were mixed with polyester diol (A): MDI: BD. The molar ratio is 1: 2.9 to 1.
At a ratio of 9, a twin-screw extruder rotating in the same direction was continuously charged by a metering pump to carry out a continuous melt polymerization reaction. When the inside of this twin-screw extruder was divided into three zones of a front portion, an intermediate portion and a rear portion, the temperature (polymerization temperature) of the intermediate portion, which was the highest temperature, was set to 220 ° C. The thermoplastic polyurethane produced was extruded continuously in water in the form of strands and then pelletized with a pelletizer. The obtained thermoplastic polyurethane pellets and ABS resin (ABS1 manufactured by Nippon Synthetic Rubber Co., Ltd.)
2) and 2) were melt-kneaded in a weight ratio of 70:30 with a 25φ extruder (cylinder temperature 200 ° C, die temperature 180 ° C), and the obtained resin composition was pelletized. The obtained resin composition pellets are injection-molded using an injection molding machine (FS80S12ASE, manufactured by Nissei Plastic Industry Co., Ltd.) under the conditions of a cylinder temperature of 175 to 200 ° C., a nozzle temperature of 200 ° C., and a mold temperature of 30 ° C. A disk-shaped molded product (120
mmφ × 2 mm thickness) was produced. The resulting molded product was evaluated for specific gravity, cold resistance, injection molding strain and hardness.
The evaluation results are shown in Table 4. Further, the pellets of the obtained resin composition were heated at a cylinder temperature of 16 using a 25φ extruder.
Extrusion molding was performed under the conditions of 5 to 200 ° C. and a die temperature of 200 ° C. to prepare a sheet-shaped molded product (thickness 1 mm). The bending resistance of the obtained sheet-shaped molded product was evaluated. The evaluation results are shown in Table 4. It was found that the above-mentioned polyurethane composition has a low specific gravity (specific gravity of 1.10 or less), and has good cold resistance, bending resistance, and injection moldability.

[Comparative Example 1] The same thermoplastic polyurethane as that obtained in Example 1 was subjected to injection molding and extrusion molding by the same operation as in Example 1 except that the ABS resin was not added. A product was produced. The obtained molded product was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4. It was found that the thermoplastic polyurethane alone had a large specific gravity and poor injection moldability (large injection molding strain).

[Examples 2 to 4 and Comparative Examples 2 to 6] Polyester diols shown in Table 3 were used in place of the polyester diol (A), and polyester diol, MDI and BD were charged in a molar ratio shown in Table 3. The same procedure as in Example 1 was carried out to obtain thermoplastic polyurethane pellets. The resulting thermoplastic polyurethane is used as is, as shown in Table 3, or in addition to it, as in Example 1, ABS resin (of the same type as used in Example 1) or AES.
Using a resin composition obtained by adding and kneading a resin (manufactured by Nippon Synthetic Rubber Co., Ltd., AES110) at a predetermined ratio, injection molding and extrusion molding were carried out to produce molded articles. The obtained molded product was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

[0044]

[Table 3]

[0045]

[Table 4]

[0046]

EFFECTS OF THE INVENTION According to the present invention, as is clear from the above examples, a resin composition having a low specific gravity and excellent cold resistance, bending resistance and injection moldability is provided.

Claims (1)

[Claims] 1. A thermoplastic polyurethane (A) is mainly used.
And a thermoplastic graft polymer (B) obtained by graft-polymerizing an aromatic vinyl compound and a vinyl cyanide compound on an elastomer, and (A) / (B)
In the resin composition having a weight ratio of 90/10 to 50/50, wherein the thermoplastic polyurethane (A) has the structural unit (1) represented by the following formula (I) and the following general formula (I): The structural unit (3) represented by III) is the main structural unit, and the molar ratio of the structural unit (1) and the structural unit (2) represented by the following formula (II) is (1) / (2). At 100/0
Within the range of 50/50, and the molar ratio of the structural unit (3) to the structural unit (4) represented by the following general formula (IV) is (3) / (4): 100/0 A thermoplastic polyurethane having a nitrogen atom content of 3% by weight or less, which is obtained by reacting a polyester diol having a number average molecular weight of 1500 to 4500 in the range of 50/50, an organic diisocyanate and a chain extender. A resin composition comprising: [Chemical 1] [Chemical 2] [Chemical 3] [Chemical 4] (In the formula, n represents an integer of 4 to 12, and Ar has 6 to 6 carbon atoms.
It represents 12 divalent aromatic hydrocarbon groups. )