KR100372801B1 - Polyamide Resin Compositions and Molded Articles - Google Patents

Abstract

The present invention provides a polyamide composition containing a polyamide resin (A) and a thermoplastic polyurethane resin (B). In the composition, the polyamide resin (A) constitutes a continuous phase, the thermoplastic polyurethane resin (B) constitutes a dispersed phase, and the tensile modulus of the composition is 7,000 kg / cm 2 or less.

Description

Polyamide Resin Compositions and Molded Articles

The present invention relates to a polyamide resin composition, an article molded from the composition, such as a tank, a tube, and the like. More specifically, the present invention is useful for the manufacture of articles having not only low tensile modulus but also excellent oil resistance (particularly, gasoline vapor permeability), heat resistance, hydrolysis resistance, chemical resistance, moldability (particularly mold release), impact resistance, and the like. It relates to a polyamide resin composition and also to articles molded from such compositions, such as gasoline tubes, hoses, packings, cams, gears and the like.

Recently, research on polymer mixtures has been advanced, and various multicomponent resin compositions having high impact resistance have been developed. In general, compositions comprising polyamide resins and olefin polymers or styrene polymers mixed with them are known as nylon. These nylons have high impact resistance or low water absorption, and examples thereof include a composition of nylon and polypropylene, a composition of nylon and ABS resin, and a composition of nylon and polypropylene rubber. However, since the polyamide resin has a high tensile modulus, an article having excellent flexibility cannot be obtained from the polyamide resin composition.

To reduce the tensile modulus of polyamide resins, polyamide elastomers, polyamide urethane copolymers, and the like are made of polyamide (nylon 6, nylon 12, aromatic polyamide, etc.) as hard segments, and polytetramethylene ether glycol as soft segments. (PTMG), polypropylene glycol (PPG), aliphatic polyester diols and the like were prepared by block copolymerization. Although these resins have low tensile modulus, they provide insufficient heat resistance and oil resistance (particularly, gasoline vapor permeability).

In addition, polyamide resin compositions comprising polyamide resins and thermoplastic polyurethane resins mixed with them to reduce their tensile modulus are known in the art. In general, however, when mixed with a relatively large amount of polyurethane resin to sufficiently reduce the tensile modulus, the thermoplastic polyurethane resin constitutes a continuous phase in the polyamide resin composition, thus providing some disadvantages due to the thermoplastic polyurethane resin. do. For example, oil resistance (particularly, gasoline vapor permeability), hydrolysis resistance, moldability (particularly, mold release) and the like can be significantly reduced.

The polyamide resin composition of the present invention comprises a polyamide resin (A) and a thermoplastic polyurethane resin (B), wherein the polyamide resin (A) constitutes a continuous phase, and the thermoplastic polyurethane resin (B) It constitutes a dispersed phase and the tensile modulus of the composition is 7,000 kg / cm 2 or less.

The invention also includes a polyamide resin composition comprising a polyamide resin (A) and a thermoplastic polyurethane resin (B), wherein the polyamide resin (A) constitutes a continuous phase and the thermoplastic polyurethane resin (B) ) Constitute the dispersed phase and the composition satisfies the following equation (I):

Where

MFR (A) represents the melt flow rate of the polyamide resin (A) at the processing temperature, MFR (B) represents the melt flow rate of the thermoplastic polyurethane resin (B) at the processing temperature, Φ _A Denotes the weight% of the polyamide resin (A) based on the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B).

In a preferred specific example, the content of the polyamide resin (A) is 60 to 20% by weight based on the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B), and the content of the thermoplastic polyurethane resin (B) is 40 to 80 weight percent.

In a preferable specific example, melting | fusing point of polyamide resin (A) is 210 degrees C or less.

The present invention also includes an article molded from the polyamide resin composition.

In a preferred specific example, the article is a tube.

Therefore, from the invention disclosed herein, (1) not only high impact resistance and low tensile coefficient, but also excellent oil resistance (particularly, gasoline vapor permeability), heat resistance, hydrolysis resistance, chemical resistance, moldability (particularly, release property), Polyamide resin composition for obtaining the article which has impact resistance etc. can be provided; (2) It became possible to provide the molded article from the polyamide resin composition.

These and other advantages of the present invention will become apparent to those skilled in the art upon reading the following detailed description with reference to the accompanying drawings.

Polyamide resins (A) that can be used in the present invention include semicrystalline resins and amorphous resins, which are generally called nylon resins. In general, the polyamide resin (A) is produced by reacting saturated dicarboxylic acids having 4 to 12 carbon atoms with diamine having 4 to 14 carbon atoms in equimolar amounts. Excess diamine may be used to provide more amino groups than the carboxyl group at the polyamide end, and excess dicarboxylic acid may also be used to provide more carboxyl groups than the amino group at the polyamide end. The polyamide resins include polyhexamethylene adipamide (6,6 nylon), polymethaxylene adipamide (MXD-6 nylon), polyhexamethylene azelamide (6,9 nylon), and polyhexamethylene dodecanoamide. (6,12 nylon); And lactams such as polycaprolactam (6 nylon), polylaurolactam (12 nylon), poly-11-amino-undecanoic acid (11 nylon), bis (p-aminocyclohexyl) methanedodecanoamide, and the like. Polyamides prepared by ring-opening reactions. The polyamide resin may be used alone, or a mixture of two or more kinds of the above resins may be used in the present invention. Copolymers containing two or more of the aforementioned dicarboxylic acids and / or diamines may also be used.

As for melting | fusing point of polyamide resin (A), 210 degrees C or less is preferable. The polyamide resin composition of the present invention is a polymer alloy in which a polyamide resin constitutes a continuous phase and a thermoplastic polyurethane resin constitutes a dispersed phase. The polymer alloy in which the polyurethane resin constitutes a continuous phase provides insufficient gasoline vapor permeability, heat resistance, and the like. In the case of a polymer alloy having a phase system in which the polyamide resin constitutes a continuous phase, it is generally required that the melt viscosity of the polyamide resin is lower than the melt viscosity of the polyurethane resin. Melt viscosity of a polyurethane resin tends to vary with its temperature when compared with a polyamide resin. More specifically, when the melting temperature of the polyurethane resin exceeds 210 ° C, the viscosity of the polyurethane resin is extremely reduced, and the polyurethane resin quickly disperses upon heating to a temperature above its melting point. Since the viscosity of the polyamide resin does not change so rapidly, the polyurethane resin has a relatively low viscosity and forms a continuous phase. Therefore, the processing temperature of the polyamide resin composition is preferably 210 ° C or lower, and the melting point of the polyamide resin (A) used in the present invention is preferably 210 ° C or lower. The polyamide resin is a polyamide resin copolymer comprising 6 nylon and / or 6,6 nylon, for example a copolymer of 6 nylon and 6,6 nylon, a copolymer of 6 nylon and 12 nylon, 6,6 nylon And a copolymer of 12 nylon, a copolymer of 6 nylon and MXD-6 nylon, and a copolymer of 6,6 nylon and MXD-6 nylon.

The thermoplastic polyurethane resin (B) which can be used in the present invention is a polymer having a polyurethane bond, which is prepared by the addition polymerization reaction of diisocyanate and polyol. In other words, thermoplastic polyurethane resins (B) are block copolymers prepared from diisocyanates and polyols and further chain extenders as main starting materials. For example, thermoplastic polyurethane resin (B) has soft segments made from polyols having an average molecular weight of 300 to 6,000, and hard segments made from chain extenders and diisocyanates having 4 to 21 carbon atoms. Various desirable properties can be obtained by selecting various types of diisocyanates, polyols and chain extenders, and combinations thereof. The thermoplastic polyurethane resin (B) can be classified into polyester polyurethane resins, polyether polyurethane resins and polycarbonate polyurethane resins according to the type of polyol contained as the soft segment. Polyester polyurethane resins and polycarbonate polyurethane resins are preferred in the present invention.

Polyester polyol can be used as a polyol which comprises polyester polyurethane resin. Acid components of the polyester polyol include aliphatic saturated dicarboxylic acids having 4 to 21 carbon atoms such as glutaric acid, adipic acid, pimelic acid, subbelic acid, azelaic acid, sebacic acid, dodecanedioic acid, and the like; And aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid and the like, and adipic acid is generally used. Diol components of polyester polyols that can be used include aliphatic and cycloaliphatic compounds having 2 to 21 carbon atoms, for example ethylene glycol, propylene glycol, trimethylene glycol, butanediol, methylpentanediol, pentanediol, hexanediol, heptanediol , Octanediol, nonanediol, decandiol, dodecanediol and the like, butanediol is generally used. Polyester polyols used as polyols of polyester polyols include esters of acid and diol components; Polymers (eg, polyethylene adipate, polybutylene adipate, polymethylpentane adipate, polynonan adipate, polynonan isophthalate); And copolymers thereof, generally polybutylene adipate is used. Lactones such as polycaprolactone can also be used as tolyester polyols.

Polyols of the polyether polyurethane resins that can be used include polyether polyols. Often used polyether polyols are polytetramethylene ether glycols.

Polyols of polycarbonate polyurethane resins that can be used include polycarbonate polyols. Polycarbonate polyols include polybutylene carbonate, polyhexamethylene carbonate, and the like.

Diisocyanates constituting the thermoplastic polyurethane resin (B) include aliphatic, cycloaliphatic and aromatic diisocyanates. Examples of the diisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, dianisidine Isocyanate, hexamethylene diisocyanate, 3,3'-ditolylene-4,4'-diisocyanate, p-xylyl diisocyanate, 1,3-cyclohexanedimethyl isocyanate, m-xylyl diisocyanate, 1,5- Naphthalene diisocyanate, trans-vinylene diisocyanate, methyl 2,6-diisocyanatohexanoate, diphenylether-4,4'-diisocyanate and isophorone diisocyanate. The above-mentioned diisocyanate compounds can be used individually or in combination.

Chain extenders include aliphatic and cycloaliphatic diols with 2 to 21 carbon atoms, butanediol is generally used.

Polyurethane resins (B) which can be used in the present invention are generally obtained by addition polymerization of polyols and diisocyanates in the presence of chain extenders.

Although the hardness (Shore A) of the thermoplastic polyurethane resin (B) is generally about 60 to 100, it is generally preferred that the hardness is low in order to reduce the tensile modulus of the article resulting from the composition of the present invention. It is presently preferred to use thermoplastic polyurethane resins (B) having a hardness (Shore A) of 90 or less. Thermoplastic polyurethane resins with higher melt viscosity, ie low melt flow rates, are better. This is because when the thermoplastic polyurethane resin (A) is mixed with the polyurethane resin (B) to produce a polymer alloy comprising a polyamide resin as a continuous phase and a thermoplastic polyurethane resin as a dispersed phase, the melt viscosity of the thermoplastic polyurethane resin is This is because higher than the melt viscosity of the polyamide resin is advantageous. The method of increasing the melt viscosity of the thermoplastic polyurethane resin is to increase its molecular weight or to partially crosslink the resin.

The first polyamide resin composition of the present invention comprises a polyamide resin (A) and a thermoplastic polyurethane resin (B), wherein the polyamide resin (A) constitutes a continuous phase, and the thermoplastic polyurethane resin (B) forms a dispersed phase. And the tensile modulus of the composition is 7,000 kg / cm 2 or less, as described above.

In the first polyamide resin composition of the present invention, the content of the polyamide resin (A) is preferably 60 to 20% by weight, based on the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B), More preferably in the range of 50 to 30% by weight. In addition, the content of the thermoplastic polyurethane resin (B) is preferably 40 to 80% by weight, more preferably 50 to 70, based on the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B). It is present in the weight percent range. In addition, as the content of the thermoplastic polyurethane resin (B) increases, it is preferable that both melt viscosity ratios (ie, melt flow rate of the polyamide resin (A) / melt flow rate of the thermoplastic polyurethane resin (B)) are high. , Especially 0.5 or more, preferably 0.5 to 100. Preferred proportions may vary depending on the resin type selected, molding temperature and the like. Therefore, by adjusting the weight ratio of the polyamide resin (A) to the thermoplastic polyurethane resin (B), their melt flow rate and the like, the polyamide resin (A) constitutes a continuous phase and the thermoplastic polyurethane resin (B ) Constitutes a dispersed phase, and the tensile modulus of the first polyamide resin composition of the present invention is 7,000 kg / cm 2 or less. Such polyamide resin compositions can provide soft articles having excellent oil resistance (particularly, gasoline resistance) and releasability.

The second polyamide resin composition of the present invention comprises a polyamide resin (A) and a thermoplastic polyurethane resin (B), as described above, the polyamide resin (A) constitutes a continuous phase and the thermoplastic polyurethane resin (B) ) Constitute the dispersed phase and satisfy the following equation (I). The following equation (I) was obtained as a result of the inventors' example illustrated in the following examples.

Where

MFR (A) represents the melt flow rate of the polyamide resin (A) at processing temperature, MFR (B) represents the melt flow rate of the thermoplastic polyurethane resin (B) at processing temperature, Φ _A is the polyamide resin The weight percent of the polyamide resin (A) based on the total weight of (A) and the thermoplastic polyurethane resin (B).

The melt flow rate is measured according to JIS K 7210 under the following conditions.

Load: 2160 g

Measurement temperature: It is measured at the processing temperature of the resin composition. The processing temperature indicates a temperature 10 to 15 ° C. higher than the melting point of the polyamide resin (A), usually about 10 ° C., preferably 210 ° C. or less. When the processing temperature exceeds 210 ° C, the viscosity of the thermoplastic polyurethane resin (B) decreases as described above, so that a continuous phase of the polyamide resin cannot be formed.

As long as the MFR values of components (A) and (B) in the second polyamide resin composition of the present invention are adjusted to satisfy the above equation (I), even if the weight ratio of component (B) increases in the composition, the polyamide resin (A) always comprises a continuous phase, and a thermoplastic polyurethane resin (B) always comprises a dispersed phase. Further, in the second polyamide resin composition of the present invention, the content of the polyamide resin (A) is preferably 60 to 60, based on the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B). 20% by weight, more preferably 50 to 30% by weight. The content of the thermoplastic polyurethane resin (B) is preferably 40 to 80% by weight, more preferably 50 to 50% based on the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B). 70 wt%. Therefore, by adjusting the weight ratio of the polyamide resin (A) to the thermoplastic polyurethane resin (B), their melt flow rate and the like, the polyamide resin (A) constitutes a continuous phase and the thermoplastic polyurethane resin (B ) Constitute the dispersed phase. The polyamide resin composition of the present invention having such a phase system has not only low tensile modulus but also excellent impact resistance, oil resistance (particularly, gasoline vapor permeability), heat resistance, hydrolysis resistance, chemical resistance, moldability (particularly, release property). It is possible to provide a soft article having a).

Since the thermoplastic polyurethane resin is compatible with the polyamide resin, it is usually not necessary to use a compatibility agent or to modify the thermoplastic polyurethane resin. If it is necessary to improve the compatibility of the thermoplastic polyurethane resin, it can be modified by a known method, for example, by acid modification with an unsaturated carboxylic acid or an anhydride thereof (eg maleic anhydride). have.

In the polyamide resin composition of the present invention, thermoplastic resins other than polyamide resin (A) and thermoplastic polyurethane resin (B), reinforcing agents, crystal nucleating agents, mold release agents, flame retardants, light or thermal stabilizers, plasticizers, etc. Antistatic agents, coloring agents, etc. can be added.

The other thermoplastic resin may be included in the polyamide resin composition in an amount such that the phase structures of the polyamide resin (A) and the thermoplastic polyurethane resin (B) are not substantially changed. Other thermoplastics include polyolefins, poly (phenylene oxides), poly (phenylene sulfides), polystyrenes, polycarbonates, polyesters, polyimides, polystyrene-butadiene copolymers, polyester elastomers, poly (phenylenes) Ether), polyacrylonitrile, butadiene rubber and the like. Preference is given to maleic acid modified resins such as maleic acid modified styrene-ethylene-butadiene copolymers, maleic acid modified ethylene-α-olefin copolymers and maleic acid modified polyester elastomers.

Reinforcing agents that can be used in the polyamide resin composition include fibrous reinforcing agents, filler reinforcing agents and the like. Fibrous reinforcing agents include carbon fiber, glass fiber, and the like, but are not limited thereto. Filler phase enhancers include talc, mica, wollastonite, calcium carbonate, various whiskers, silica, kaolin, montmorillonite, clay, and the like, but are not limited thereto. The amount of reinforcing agent is preferably added up to about 50 parts by weight based on 100 parts by weight of the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B).

The nucleating agent includes talc, clay, calcium carbide, sodium phenyl phosphinate, alumina, finely divided polytetrafluoroethylene, and the like, but is not limited thereto. The amount of nucleating agent is preferably added up to about 3 parts by weight based on 100 parts by weight of the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B).

Release agents include, but are not limited to, metal salts of stearic acid, metal salts of montan wax, stearyl alcohol, silicone oil, and the like. The amount of the releasing agent is preferably added up to about 2 parts by weight based on 100 parts by weight of the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B).

Flame retardants include, but are not limited to, halogen-based flame retardants, non-halogen-based flame retardants. Halogen-based flame retardants include brominated polystyrene, polybromodiphenyl ethers, high molecular weight brominated epoxy resins, and the like. Non-halogen flame retardants include antimony trioxide, melamine cyanurate, and red. Particular preference is given to mixtures of halogen-based flame retardants and antimony trioxide. The amount of the flame retardant is preferably added up to about 35 parts by weight based on 100 parts by weight of the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B).

Light and thermal stabilizers include, but are not limited to, mixtures of carbon black, copper halides and potassium halides, hindered phenol stabilizers, phosphorus stabilizers, benzotriazole stabilizers, benzophenone stabilizers, and mixtures thereof. The amount of light and heat stabilizer is preferably added up to about 4 parts by weight relative to 100 parts by weight of the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B).

Plasticizers include, but are not limited to, dioctyl phthalate, dibutylbenzyl phthalate, butylbenzyl phthalate, hydrocarbon oils, N-n-butylbenzene sulfonamides, o-toluene ethylsulfonamides, p-toluene ethylsulfonamides, and the like. The amount of plasticizer is preferably added up to about 40 parts by weight based on 100 parts by weight of the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B). At temperatures above about 5 ° C. above the melting point of the polyamide resin (A), preferably 5 to 15 ° C. higher, conventional mixers such as roller kneaders, Banbury mixers, single and multi-screw extruders, etc. Each component of the polyamide resin composition of the present invention is kneaded and molded to prepare various articles. The method of molding the composition includes, but is not limited to, conventional methods such as injection molding, rotary molding, extrusion, drawing, and the like. Extrusion can effectively produce the tube.

The polyamide compositions of the present invention are particularly useful for the production of tanks such as gasoline tanks, oil tanks which require oil resistance (in particular, gasoline resistance); It can be suitably used for the manufacture of tubes such as gasoline tubes. In addition, the polyamide composition of the present invention is suitably used for parts that are problematic if water is absorbed and the dimensions thereof are changed in parts such as home appliances, sundries, and automobiles. Furthermore, the polyamide composition of the present invention can be used for ski boots, wheel covers, bumpers, patches, and the like.

Example

The following examples illustrate the present invention in detail and do not limit the present invention.

Various physical properties and test results described in the Examples are measured as follows.

(1) melt flow rate

The melt flow rate is measured according to JIS K 7210 (measurement condition: load 2160 g).

(2) Hardness (Shore A)

Hardness (Shore A) is measured according to ASTM D-2240.

(3) tensile modulus

Tensile modulus is measured according to ASTM D-638.

(4) Grain size of the domains forming the dispersed phase, determination of the continuous phase.

The tensile dumbbell of the JIS 3 form was formed using the pellet obtained in the following example or comparative example, and the cross section of the dumbbell in the resin flow direction using a transmission electron microscope (× 10,000) by RuO ₄ .PTA dyeing ultra-thin method. The continuous phase is determined by observing.

(5) Nasoline vapor permeability

(A) Test piece (thin film) manufacturing method.

A Shinto SF type compression molding machine (manufactured by Shinto Metal Industries) is set at a temperature 15 ° C higher than the melting point of the polyamide resin in the compositions of the following examples and comparative examples. The pellets obtained in Examples or Comparative Examples are filled into a mold having a thickness of 0.2 mm, and then sandwiched between Teflon sheets sandwiched between iron plates. It is filled in the above-mentioned press without pressurization, held for 1 minute, and then gradually pressurized to a value of 100 kg / cm 2 while releasing air. After holding for about 10 seconds under pressure conditions, the pressure is released to obtain a thin film (ie, a specimen) of 0.2 mm thickness.

(B) Nasoline vapor permeability (g.mm/㎡.day.atm)

A cup-shaped 0.04 L brass container with an opening of 50 mm diameter is filled with gasoline to fill approximately half the volume of the container, sealed with a specimen in the opening, and screwed. After leaving the vessel in a controlled temperature oven of 40 ± 1 ° C. for 4 days, the reduced weight of gasoline is calculated from the residual amount of gasoline and the gasoline vapor permeability of the test piece is calculated according to the following equation (II).

Where

D denotes the gasoline vapor permeability (permeability), t denotes the film thickness of the test piece (mm), Q denotes the reduced weight of gasoline (g / day), and S denotes the test piece in contact with the gasoline smoke. Area (m 2) is shown. Also, t is measured to two decimal places using a caliper. Q is measured to the third decimal place.

(6) hydrolysis resistance

Hydrolysis resistance is measured as follows. Dumbbells of the JIS 3 type were manufactured using the pellets of Examples or Comparative Examples. For the purpose of removing the water absorbed into the dumbbell, the dumbbell is immersed in hot water at 95 ° C. for 60 days and vacuum dried at 80 ° C. for 2 days. The tensile strength of the dumbbell is obtained by pulling the dumbbell at a rate of 100 mm / min while increasing the force, measuring the burst strength at 23 ° C. under 65% RH, and then calculating it using the following equation.

The tensile strength of the immersed dumbbell was compared with that of the original dumbbell, and the percent holding of the tensile strength was calculated. Evaluation of hydrolysis resistance is as follows:

0: 50% or more retention rate

X: Less than 50% retention

(7) release

The release property of the article obtained using the pellet of the following example or the comparative example is evaluated using the injection molding machine according to the following conditions. The molding machine used was FS-75 manufactured by Nissei Plastics Industrial Company; Injection time is 10 seconds; Cooling time is variable; The cylinder set temperature is 10 ° C. above the melting point of the polyamide resin; Mold temperature is room temperature; The article form is a plate (100 mm × 100 mm × 2 mm side guard).

The determination of dysplasia is as follows:

o: If the cooling time is set within 10 seconds, continuous molding is possible without any problem.

x: When the cooling time is within 10 seconds, continuous molding is impossible due to deformation, mold release failure, etc. when the article is released from the mold by the ejector pin.

Example 1

A copolymer of 6 nylon and 6,6 nylon as polyamide resin (A) (melting point is 190 ° C., melt flow rate is 65 g / 10 min (200 ° C.)) and caprolactone as thermoplastic polyurethane resin (B) Polyester-based thermoplastic polyurethanes (PANDEX T-5080 manufactured by Dainippon Ink and Chemicals Inc.) were mixed at the weight ratios shown in Table 1, followed by 30 mm twin-screws at a screw speed of 80 rpm. The extruder (manufactured by Ikegai Corporation) was used to knead at 200 ° C. (temperature 10 ° C. above the melting point (190 ° C.) of the polyamide resin (A)).

The resulting composition was discharged from the extruder, cooled on a water bath and cut with a cutter, then vacuum dried at 80 ° C. for 16 hours and molded into pellets of 2 mm diameter and 2 mm length. The properties of the pellets were evaluated. Table 1 shows the results.

In Table 1, Ia corresponds to equation (I), i.e., the left side of the following equation.

Where

MFR (A) represents the melt flow rate of the polyamide resin (A) at processing temperature and MFR (B) represents the melt flow rate of the thermoplastic polyurethane resin (B) at processing temperature.

Ib corresponds to equation (I), that is, the right side of the following equation.

Ib = -0.081Φ _A + 3.84

Where

Φ _A represents the weight percent of the polyamide resin (A) to the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B).

Comparative Examples 1 to 4

The composition was obtained by the same method as Example 1 except changing the mixing ratio of the polyamide resin (A) with respect to a thermoplastic polyurethane resin (B) as shown in Table 1. The resulting composition was molded into pellets and the properties of the pellets were evaluated by the same method as in Example 1. Table 1 illustrates the results.

Table 1

P A: Polyamide Resin (A)

TPU: Thermoplastic Polyurethane Resin (B)

Examples 2-8

The composition was obtained by the same method as Example 1 except mixing each of the polyamide resin (A) and the thermoplastic polyurethane resin (B) of Table 2 in the weight ratio shown in Table 2. The resulting composition was molded into pellets and the properties of the pellets were evaluated by the same method as in Example 1. Table 2 presents the results.

Comparative Examples 5-10

The composition was obtained by the same method as Example 1 except mixing each of the polyamide resin (A) and the thermoplastic polyurethane resin (B) of Table 2 in the weight ratio shown in Table 2. The resulting composition was molded into pellets and the properties of the pellets were evaluated by the same method as in Example 1. Table 3 presents the results.

The abbreviations of Tables 2 and 3 are as follows:

NY 6/66 copolymer: 6 nylon / 6.6 nylon (80/20 weight ratio) copolymer

T-5080: Caprolactone polyester-type polyurethane resin with surface hardness (Shore A) 80, Pandex T-5080 (manufactured by Dainippon Ink and Chemicals Incorporated)

E-580F: caprolactone polyester-type polyurethane resin having surface hardness (Shore A) 80; Miralactran E580F (manufactured by Nippon Miralacran Company Limited)

TABLE 2

P A: Polyamide Resin (A)

TPU: Thermoplastic Polyurethane Resin (B)

TABLE 3

P A: Polyamide Resin (A)

TPU: Thermoplastic Polyurethane Resin (B)

Examples 9-12

The polyamide resins (A) and thermoplastic polyurethane resins (B) of Table 4 were mixed at the weight ratios shown in Table 4, followed by the use of a 30 mm twin-screw extruder (manufactured by Ikegai Corporation). It was kneaded at the temperature shown. The rotation speed of the screw was 80 rpm. The resulting composition was molded into pellets and the properties of the pellets were evaluated by the same method as in Example 1. The results are shown in Table 4.

Comparative Examples 11-13

After mixing the polyamide resin (A) of Table 4 and the thermoplastic polyurethane resin (B) in the weight ratios shown in Table 4, the screw rotation speed using a 30 mm twin-screw extruder (manufactured by Ikegai Corporation) It was kneaded at 80 rpm at the temperatures shown in Table 4. The resulting composition was molded into pellets and the properties of the pellets were evaluated by the same method as in Example 1. The results are shown in Table 4. The abbreviations in Table 4 are as follows:

NY-66: 6,6 nylon; T-662 (manufactured by Toyo Boseki Incorporated)

MXD-6: polymethaxylene adipide; T-600 (manufactured by Toyo Boseki Incorporated)

NY-6: 6-nylon; T-802 (manufactured by Toyo Boseki Incorporated)

NY 6/66 copolymer: 6 nylon / 6,6 nylon (80/20 weight ratio) copolymer

NY 6/12 copolymer: 6 nylon / 12 nylon (75/25 weight ratio) copolymer

NY 12: 12 nylon; L-1801 (manufactured by Daicel-Hulse)

T-5080: caprolactone polyester-type polyurethane resin having surface hardness (Shore A) 80; Pandex T-5080 (manufactured by Dainippon Ink and Chemicals Incorporated)

E-580F: Caprolactone polyester-type polyurethane resin with a surface hardness (Shore A) 80: Miractran E 580F (manufactured by Nippon Miractran Company Limited)

Table 4

P A: Polyamide Resin (A)

TPU: Thermoplastic Polyurethane Resin (B)

Examples 13-16

After mixing the polyamide resin (A) of Table 5 and the thermoplastic polyurethane resin (B) in the weight ratios shown in Table 5, the screw rotation speed using a 30 mm twin-screw extruder (manufactured by Ikegai Corporation) It was kneaded at 80 rpm at the temperatures shown in Table 5. The resulting composition was molded into pellets and the properties of the pellets were evaluated by the same method as in Example 1. The results are shown in Table 5.

Comparative Examples 14-15

After mixing the polyamide resin (A) of Table 5 and the thermoplastic polyurethane resin (B) in the weight ratios shown in Table 5, the screw rotation speed using a 30 mm twin-screw extruder (manufactured by Ikegai Corporation) It was kneaded at 80 rpm at the temperatures shown in Table 5. The resulting composition was molded into pellets and the properties of the pellets were evaluated by the same method as in Example 1. The results are shown in Table 5.

The abbreviations in Table 5 are as follows:

NY 6/66 copolymer: 6 nylon / 6,6 nylon (80/20 weight ratio) copolymer

E-580F: Caprolactone polyester-type polyurethane resin with a surface hardness (Shore A) 80: Miractran E580F (manufactured by Nippon Miractran Company Limited)

E-580F (1): Crosslinking thickener (Crossnate EM-30 manufactured by Dainichi Seika Color and Chemicals Manufacturing Co., Ltd.) to increase melt viscosity (ie to reduce its melt flow rate) 5 E-580F with weight percent added

E-580F (2): E-580F with 10% by weight of crosslinking thickener (Crossnate EM-30, manufactured by Dainichi Seika Color and Chemicals Manufacturing Co., Ltd.) to increase melt viscosity.

E-1080A: Adipate polyester-type polyurethane resin with surface hardness (Shore A) 80, Toyobo Urethane E1080A (manufactured by Toyobo Co., Ltd.)

E-1080A (1): E-1080A with 5% by weight of crosslinking thickeners (Crossnate EM-30, manufactured by Dainichi Seika Color and Chemicals Manufacturing Co., Ltd.) to increase melt viscosity.

E-1080A (2): E-1080A with the addition of 10% by weight of crosslinking thickeners (Crossnate EM-30, manufactured by Dainichi Seika Color and Chemicals Manufacturing Co., Ltd.) to increase melt viscosity.

Table 5

P A: Polyamide Resin (A)

TPU: Thermoplastic Polyurethane Resin (B)

Examples 17-20

In the forming step, the MFR ratio of the polyamide resin (A) and the thermoplastic polyurethane resin (B) (i.e., the MFR of the polyamide resin (A) / the thermoplastic polyurethane resin (B)) and the surface hardness (Shore A) The composition was obtained by the same method as Example 5 except changing as shown in Table 6. After molding the resulting composition into pellets, the properties of the pellets were evaluated by the same method as in Example 5. The results are shown in Table 6.

Table 6

P A: Polyamide Resin (A)

TPU: Thermoplastic Polyurethane Resin (B)

As shown in Tables 1 to 6, the composition of the present invention, in which the polyamide resin constitutes a continuous phase, has excellent gasoline vapor permeability and releasability. In forming the continuous phase of the polyamide resin, there are various factors such as the resin form, the amount of each mixed component, the MFR ratio and the like. For example, when the Ia value is greater than the Ib value, the polyamide resin forms a continuous phase. It is to be understood that the surface hardness of the thermoplastic polyurethane resin may be lowered to reduce the tensile rate of the composition.

Example 21

The log (MFR (A) / MFR (B)) values of each of the compositions obtained in Examples 1-16 and Comparative Examples 2, 3 and 5-15 were plotted as a function of the Φ _A value in the figure, with MFR (A) Represents the melt flow rate of the polyamide resin (A) at the processing temperature, MFR (B) represents the melt flow rate of the thermoplastic polyurethane resin (B) at the processing temperature, Φ _A represents the polyamide resin (A) and the thermoplastic The weight percentage of the polyamide resin (A) is shown based on the total weight of the polyurethane resin (B).

The plot in the figure shows the correlation between the Φ _A values and the log (MFR (A) / MFR (B)) values of the appropriate composition. It can be seen from the figure that a suitable composition is present at the top of the straight line X, ie the composition satisfies equation (I). In this case, it can be understood that the polyamide constitutes a continuous phase in the polyamide resin composition. The polyamide resin composition provides excellent gasoline vapor permeability and releasability.

As shown in the foregoing examples and comparative examples, the polyamide resin composition of the present invention has low tensile modulus and excellent gasoline vapor permeability, thus providing various advantages and used in various articles. For example, when the composition is used as a gasoline hose, the hose does not require a particular connection when connected to the intended article.

Various other modifications may be made and apparent to those skilled in the art without departing from the scope and spirit of the invention. Accordingly, the claims should not be limited to the description set forth herein but should be construed broadly.

1 shows the relationship between the Φ _A value and the log (MFR (A) / MFR (B)) value of the compositions obtained in Examples 1-20 and Comparative Examples 1-15.

Claims (8)

A polyamide resin composition having a tensile modulus of 7,000 kg / cm 2 or less and comprising a polyamide resin (A) and a thermoplastic polyurethane resin (B), (1) the polyamide resin (A) is present from 50% to 30% based on the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B), and constitutes a continuous phase, (2) A polyamide resin composition in which the thermoplastic polyurethane resin (B) is present at 50% to 70% based on the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B) and constitutes a dispersed phase. The method of claim 1, The polyamide resin composition whose melting | fusing point of polyamide resin (A) is 210 degrees C or less. A polyamide resin composition having a tensile modulus of 7,000 kg / cm 2 or less and comprising a polyamide resin (A) and a thermoplastic polyurethane resin (B), (1) the polyamide resin (A) is present at 50% to 30% based on the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B) and constitutes a continuous phase; (2) the thermoplastic polyurethane resin (B) is present from 50% to 70% based on the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B) and constitutes a dispersed phase; (3) The polyamide resin composition wherein the polyamide composition satisfies the following equation (I): Where MFR (A) represents the melt flow rate of the polyamide resin (A) at the processing temperature, MFR (B) represents the melt flow rate of the thermoplastic polyurethane resin (B) at the processing temperature, and Φ _A is the polyamide resin based on the total weight of the polyamide resin (A) and the thermoplastic polyurethane resin (B). The weight% of (A) is shown. The method of claim 3, The polyamide resin composition whose melting | fusing point of polyamide resin (A) is 210 degrees C or less. An article molded from the polyamide resin composition of claim 1. The method of claim 5, The article is a tube. An article molded from the polyamide resin composition of claim 3. The method of claim 7, wherein The article is a tube.