JPH036944B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyamide resin composition that has excellent rigidity, low-temperature impact resistance, salt water resistance, and moldability. Polyamide resins are expected to be in great demand as engineering plastics due to their excellent physical properties. However, low temperature impact resistance, water resistance,
Performance such as salt water resistance is not sufficient, and improvements are desired. For example, as a method of improving impact resistance such as Izotsu impact strength,
Publication No. 12546, Japanese Patent Publication No. 1983-44108, Japanese Patent Publication No. 1983
In prior art documents such as JP-A-9661 and JP-A-55-9662, there are A method of compounding an elastomeric polymer has been proposed. The compositions proposed in these prior art documents all have improved impact resistance such as Izot impact strength.
The rigidity is greatly reduced, and furthermore, the falling weight impact strength at low temperatures is insufficient, and these compositions have the disadvantage that it is difficult to obtain actual molded products with high rigidity and high impact resistance. Furthermore, these compositions often have excessively low melt fluidity, and depending on the molding method, they also have the disadvantage of low molding processability. Furthermore, these compositions have poor water resistance, especially hydrolysis resistance, under conditions of contact with salt water such as various alkali metal salts or alkaline earth metal salts, and are used in fields where such performance is required, particularly automotive parts. Its use was also restricted. In addition, as a method to improve water resistance such as hygroscopicity or salt water resistance of polyamide resin,
53-80014, JP-A-56-167751, JP-A-56-109247, and JP-A-56-157451 disclose that polyamide resin contains ethylene as one component.
A method of blending a neutralized α,β-unsaturated monocarboxylic acid copolymer (ionomer resin) has been proposed. Although the compositions proposed in these prior art documents can improve water resistance such as water absorption and salt water decomposition resistance, they have a drawback in that they are inferior in the effect of improving low-temperature impact resistance. Furthermore, as a method for improving the decrease in rigidity of the polyamide resin composition mentioned above, JP-A-57-8246 discloses a graft-modified composition of a crystalline polyolefin and an ethylene/α-olefin elastic copolymer. A method of blending has been proposed. However, with this method, it is difficult to control the melt fluidity of the modified polyolefin and the modified ethylene/α-olefin elastic copolymer in the graft modified product due to crosslinking, and as a result, it is difficult to control the melt fluidity of the modified polyolefin and the modified ethylene/α-olefin elastic copolymer. is no longer obtained, the temperature range for improving impact resistance is significantly narrowed, and the improvement effect is also small. In particular, the low-temperature Izot impact strength and falling weight impact strength at -20°C or lower are significantly reduced, and the melt flowability of the composition is reduced. It also has the disadvantage that it also decreases. As a result of studying methods for developing a polyamide resin composition with excellent performance, the present inventors found that a specific amount of modified crystalline ethylene polymer and a specific amount of α-olefin elasticity were added to the polyamide resin. Compositions containing polymers have significantly improved rigidity, impact resistance such as low-temperature isot impact strength and low-temperature falling weight impact strength below -20°C, stress crack resistance, and water absorption and salt water resistance. It was discovered that the water resistance such as salt water decomposition resistance under these conditions is significantly improved, and that this composition has excellent moldability because the melt flowability does not decrease too much, and the present invention was achieved based on this finding. To summarize the present invention, the present invention comprises polyamide (A),
A polyamide composition comprising a modified crystalline ethylene polymer (B) and an α-olefin elastic polymer (C), wherein the composition of each component in the composition is 100% by weight of the polyamide (A). %, the modified crystalline ethylene polymer (B) is in the range of 1 to 200 parts by weight,
The α-olefin elastomer (C) is 1 or more.
100 parts by weight of the modified crystalline ethylene polymer (B) is a crystalline ethylene polymer containing ethylene as a main component.
It is obtained by graft copolymerizing an unsaturated carboxylic acid or its derivative component unit in the range of 0.01 to 10 parts by weight based on the weight part, the crystallinity is in the range of 50% or more, and the melt flow rate at 190 ° C. [MFR190℃] is 0.01 to 50g/
[] The α-olefin elastomer (C) is within the range of 10 min.
The main component is an olefin component unit, the crystallinity is in the range of 40% or less, and the melt flow rate at 190°C [MFR190°C] is in the range of 0.01 to 50 g/10 min; The gist of the invention is a polyamide composition characterized by: Polyamide used in the composition of the invention
(A) has a molecular weight sufficient to produce a molded article, and is obtained by condensing equimolar amounts of a saturated organic dicarboxylic acid having 4 to 12 carbon atoms and an organic diamine having 2 to 13 carbon atoms. It can be manufactured by Here, if necessary, diamine can be used in the polyamide so that the amine group ends are in excess compared to the carboxyl group ends, or conversely, dicarboxylic acid can be used so that the carboxylic acid groups are in excess. You can also do it. These polyamides can also be produced from the amine and acid-forming derivatives and amine-forming derivatives, such as esters, acid chlorides, amine salts, and the like. Typical dicarboxylic acids used to make polyamides include adipic acid, pimelic acid, suberic acid, sebacic acid and dodecanedioic acid. On the other hand, typical diamines include hexamethylene diamine and octamethylene diamine. Furthermore, polyamides can also be produced by self-condensation of lactams. Examples of polyamides include polyhexamethylene adipamide (6.6 nylon), polyhexamethylene azelamide (6.9 nylon), polyhexamethylene sebaamide (6.10 nylon) and polyhexamethylene dodecanoamide (6.12 nylon), polybis(4-aminocyclohexyl)methandodecanamide or polyamides prepared by ring opening of lactams, i.e. polycaprolactam (nylon 6), polylauritulactam or poly-11
- There is aminoundecanoic acid. It is also possible to use polyamides produced by polymerization of at least two amines or acids used to produce the polyamides mentioned above, for example polymers made from adipic acid and isophthalic acid and hexamethylene diamine. be. It is also possible to use blends of polyamides such as nylon 6.6 and mixtures of nylon 6. The condensation polyamide used in the present invention is preferably polyhexamethylene adipamide (6.6 nylon) or polyhexamethylene azeramide (6.9 nylon).
and polycaprolactam (nylon 6). The modified crystalline ethylene polymer (B) blended into the polyamide composition of the present invention contains an unsaturated carboxylic acid or its derivative component unit based on 100 parts by weight of the crystalline ethylene polymer containing ethylene as a main component.
It is obtained by graft copolymerization in the range of 0.01 to 10 parts by weight, the crystallinity is in the range of 50% or more, and the melt flow rate at 190°C [MFR190
°C] is required to be in the range of 0.01 to 50 g/10 min, and furthermore, the amount of unsaturated carboxylic acid or its derivative component unit is 0.05 to 100 parts by weight of the crystalline ethylene polymer containing ethylene as the main component. Graft copolymerized in a range of 5 parts by weight,
Its crystallinity is in the range of 60 to 90%, and
Melt flow rate at 190℃ [MFR190℃]
is preferably in the range of 0.05 to 20g/10min. Furthermore, the modified crystalline ethylene polymer
Other physical properties of (B) are that the molecular weight distribution (w/n) is usually in the range of 1.5 to 50, preferably 3 to 20, and the melting point is usually 60 to 135°C, preferably
It is in the range of 80 to 130℃. If the grafting ratio of the unsaturated carboxylic acid or its derivative component unit of the modified crystalline ethylene polymer is less than 0.01 part by weight, the compatibility with polyamide will deteriorate, the impact strength of the polyamide composition will decrease, and the amount of 10 parts by weight will decrease. When the size is larger, the degree of crosslinking of the graft modified product increases, and even if it is blended into polyamide, the effect of improving the impact resistance of the composition decreases. When the crystallinity of the modified crystalline ethylene polymer is less than 50%, the rigidity of the polyamide composition decreases and the melt flow rate decreases.
If it is less than 0.01 g/10 min, the impact resistance and melt fluidity of the polyamide composition will decrease, and if it is more than 50 g/10 min, the impact resistance will decrease. The base polymer constituting the modified crystalline ethylene polymer is a homopolymer of ethylene or a copolymer containing ethylene as a main component and an α-olefin other than ethylene, and is a highly crystalline ethylene polymer. It is a combination. Its ethylene content is usually in the range of 70 mol% or more, preferably 80 mol% or more, its crystallinity is usually in the range of 50% or more, preferably 60% or more, and its melt flow rate [MFR190
°C] is usually 0.01 to 50g/10min, preferably
It is in the range of 0.05 to 20g/10min. When the crystalline ethylene polymer is an ethylene/α-olefin copolymer, the α-olefin component units include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, and 1-hexene. ,
Examples include 1-octene, 1-decene, and 1-dodecene. Examples of the unsaturated dicarboxylic acid or its derivative unit as the graft monomer component constituting the modified crystalline ethylene polymer (B) include acrylic acid, methacrylic acid, maleic acid, fumaric acid,
itaconic acid, citraconic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, endocys-
Bicyclo[2.2.1]hept-5-ene-2,3-
Dicarboxylic acid (nadic acid), methyl-endocys-bicyclo[2.2.1]hept-5-ene-2,
Unsaturated dicarboxylic acids such as 3-dicarboxylic acid (methylnadic acid), derivatives of unsaturated dicarboxylic acids such as acid halides, amides, imides, acid anhydrides, and esters of the unsaturated dicarboxylic acids,
Specific examples include maleyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, and glycidyl maleate. Among these, unsaturated dicarboxylic acids or their acid anhydrides are preferred, and maleic acid, nadic acid, and their acid anhydrides are particularly preferred. To produce the modified crystalline ethylene polymer by graft copolymerizing the graft monomer selected from the unsaturated dicarboxylic acids or derivatives thereof onto the crystalline ethylene polymer, various conventionally known methods can be employed. Can be done. For example, there is a method in which a crystalline ethylene polymer is melted and a graft monomer is added thereto to carry out graft copolymerization, or a method in which the crystalline ethylene polymer is dissolved in a solvent and a graft monomer is added therein to carry out graft copolymerization. In any case, in order to efficiently graft copolymerize the graft monomer, it is preferable to carry out the graft copolymerization in the presence of a radical initiator. Grafting reaction is usually 60 to 350℃
carried out at a temperature of The ratio of radical initiator used is usually 100 parts by weight of crystalline ethylene polymer.
It ranges from 0.01 to 20 parts by weight. Examples of the radical initiator include organic peroxides, organic peresters, and azo compounds. The α-olefin elastic polymer (C) blended into the polyamide composition of the present invention has α-olefin as its main component, and has a crystallinity of 40% or less, and Melt flow rate at 190℃ [MFR190℃] is 0.01 to 50g/
It is necessary that the crystallinity is within the range of 10 min, the crystallinity is within the range of 30% or less, and the melt flow rate [MFR190℃] is between 0.05 and 30%.
Preferably, it is within the range of 20g/10min. Regarding other physical properties of the α-olefin elastic polymer, the glass transition temperature is usually in the range of -10°C or lower, preferably -20°C or lower. If the degree of crystallinity of the α-olefin elastomer polymer is higher than 40%, the effect of improving the impact resistance of the polyamide composition will not decrease. In addition, the melt flow rate of the α-olefin elastomer at 190°C is
If it is less than 50g/10min, the impact resistance of the polyamide composition will decrease, and if it is less than 0.01g/10min, the impact resistance of the polyamide composition will decrease.
When the time is greater than 10 min, the dispersibility in polyamide decreases, and the impact resistance and melt flowability of the polyamide composition decrease. Here, the α-olefin component units include ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1
-Pentene, 1-hexene, 1-octene, 1-
Examples include decene and 1-dodecene. The α-olefin-based elastic polymer is usually composed of a mixture of two or more α-olefin components, and may contain a small amount of other copolymerizable components in addition to these α-olefin component units. I can't help it. Copolymerizable components other than α-olefin include non-conjugated diene components such as 1,4-hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, and 2,5-norbonadiene, butadiene, isoprene, piperylene, etc. Examples include conjugated diene components.
The content of α-olefin component units constituting the α-olefin elastic polymer is usually 85 mol% or more,
Preferably it is in the range of 90 mol% or more. Examples of the α-olefin-based elastic polymer include ethylene/propylene copolymer, ethylene/1-butene copolymer, ethylene/4-methyl-1-pentene copolymer, ethylene/1-hexene copolymer, and ethylene.・1-octene copolymer, ethylene/1-decene copolymer, propylene/ethylene copolymer, propylene/1-butene copolymer, propylene/4
-Methyl-1-pentene copolymer, propylene/
α-olefin elastic copolymers such as 1-octene copolymer, propylene/1-decene copolymer, propylene/1-dodecene copolymer, ethylene/propylene/1,4-hexadiene copolymer, ethylene/propylene・Dicyclopentadiene copolymer, ethylene propylene 5-ethylidene-2
-Norbornene copolymer, ethylene/propylene/2,5-norbonadiene copolymer, ethylene/1-butene/1,4-hexadiene copolymer, ethylene/1-butene/cyclopentadiene copolymer, ethylene/1- Examples include α-olefin/non-conjugated diene elastic copolymers such as butene/5-ethylidene-2-norbornene copolymers. Among these α-olefin-based elastic polymers, α-olefin-based elastic polymers containing ethylene and/or propylene component units as main components are preferred, and in particular, ethylene/α-olefin elastic copolymers or Preferably, it is a propylene/α-olefin elastomeric polymer. In the polyamide composition of the present invention, the blending ratio of the modified ethylene polymer (B) to 100 parts by weight of the polyamide (A) must be in the range of 1 to 200 parts by weight, and more preferably 5 to 200 parts by weight.
Preferably it is in the range of 150 parts by weight. When the blending ratio of the modified ethylene polymer exceeds 200 parts by weight, the rigidity, heat-resistant rigidity, and melt fluidity of the polyamide composition decrease, and when it decreases below 1 part by weight, the impact resistance of the polyamide composition decreases. , stress crack resistance and water resistance are reduced. In addition, the α-olefin elastic polymer (C) based on 100 parts by weight of the polyamide (A)
It is necessary that the blending ratio is in the range of 1 to 100 parts by weight, more preferably in the range of 5 to 80 parts by weight, and particularly preferably in the range of 5 to 50 parts by weight.
When the blending ratio of the modified olefin polymer exceeds 100 parts by weight, the rigidity of the polyamide composition
Thermal stiffness and melt flowability are reduced, and when the amount is less than 1 part by weight, the impact resistance, stress crack resistance and water resistance of the polyamide composition are reduced. In addition to the above-mentioned three essential components, the composition of the present invention may optionally contain an antioxidant, an ultraviolet absorber, a photoprotectant, a phosphite stabilizer, a peroxide decomposer, a basic adjuvant, and an additive. Contains fillers such as nucleating agents, plasticizers, lubricants, antistatic agents, flame retardants, pigments, dyes, carbon black, asbestos, glass fibers, potassium titanate whiskers, mica, kaolin, talc, silica, and silica alumina. It is also possible. Furthermore, other polymers can be blended into the composition of the present invention within a range that does not impair its physical properties.
The blending ratio of these additives is within an appropriate range. The polyamide compositions of the present invention are prepared by melt mixing in a variety of ways. For example, there may be a method in which two optional essential components are premixed and then mixed with the remaining other components, or a method in which three essential components are simultaneously mixed with other remaining components added as needed. Moreover, the above-mentioned additives, such as antioxidants, can be added at any of these stages as necessary. The composition of the present invention has excellent properties such as rigidity, impact resistance, water resistance, and melt flowability. Among them, when producing the composition, a premix obtained by preliminary melting and mixing of component (B) and component (C),
A composition obtained by melt-mixing the polyamide (A) component has particularly excellent performance. Melt flowability [melt flow rate [MFR, 235°C, 1000g load]] of the polyamide composition of the present invention
is usually 0.1 to 500g/10min, preferably 0.2
The range is from 100g/10min. The polyamide composition of the present invention can be molded into various shapes by various conventionally known melt molding methods. Examples include methods such as injection molding, extrusion molding, compression molding, and foam molding, and are used in a wide range of applications including automobile parts, electrical appliances, and electrical parts. Next, the present invention will be specifically explained using examples. In addition, in the method of the present invention, crystallinity and melt flow rate at 190°C [MFR190
℃] was measured by the following method. Crystallinity: Measured by X-ray diffraction at 230°C. Melt flow rate [MFR190℃]: ASTM D
-1238-79 Measured under E conditions (190°C, 2160g). Example 1 Maleic anhydride modified ethylene polymer [MFR190℃, 1.50g/10min, density 0.95g/
cm ³ , crystallinity 71%, maleic anhydride unit amount: 0.9 parts by weight per 100 parts by weight of base ethylene polymer] and ethylene-propylene copolymer [ethylene content
80mol%, MFR190℃0.80g/10min, density 0.87
g/cm ³ , crystallinity 15%] were premixed using a 30 mmφ extruder (L/D=28, 230° C.) to give the mixture shown in Table 1. Next, this premix and nylon 6 [manufactured by Toray Industries, Inc., Amiran 1021XF, MFR3.74]
g/10 min, Q conditions] were mixed in the proportions shown in Table 1 to prepare a dry blend consisting of two types of pellets. Furthermore, the mixture was supplied to a single screw extruder (L/D=28, 30 mmφ) set at 260° C. to prepare a melt blend (pellet shape). The pellets were vacuum-dried at 100° C. for one day and night, and then injection molded under the following conditions to prepare specimens for measuring physical properties. Cylinder temperature: 260°C Injection pressure: 650Kg/cm ² Injection time: 10sec Mold temperature: 80°C Subsequently, physical properties were evaluated using the following method. MFR measurement; ASTM D-1238-79 Q conditions
MFR was measured. Bending test: using a 1/8″ thick test piece, ASTM
Flexural modulus FM (Kg/cm ² ) and bending yield strength FS (Kg/cm ² ) were measured using D-790-80. The test pieces were conditioned for 3 days in a constant temperature and humidity room at 23°C and 50% RH. Falling weight impact strength: A weight of a certain shape is dropped from a height of 90cm onto a test piece (diameter 50mmφ, thickness 1.2mm) placed horizontally at -60℃, and a certain number of pieces are tested by varying the weight of the weight. Falling weight impact strength was evaluated based on the weight (g) of weight required for 50% of the pieces to break. The condition of the test piece was adjusted at 23
The test was carried out for 3 days in a constant temperature and humidity room at 50% RH. Izot impact strength: Using a 1/8" thick test piece, the notched isot impact strength was measured at 23°C and -40°C according to ASTM D256. The test piece was conditioned in a constant temperature and humidity chamber at 23°C and 50% RH. Water absorption test: According to ASTM D570, a test piece (2 inches in diameter, 1/8 inch in thickness) was dried at 100°C for 24 hours, and then subjected to a water absorption test in water at 50°C for 48 hours.
The water absorption rate (%) was determined from the weight change rate of the test piece. The results are shown in Table 1. Examples 2 to 13, Comparative Examples 1 to 4 The same method as in Example 1 was used except that the modified crystalline ethylene polymer and α-olefin elastomer shown in Table 1 were used in the proportions shown in Table 1. A blend was prepared and its physical properties were measured. The results are shown in Table 1. Comparative Example 5 Crystalline ethylene polymer (MFR190℃3.24g/
10min, density 0.95g/cm ³ , crystallinity 72%) and 40 parts by weight of ethylene-propylene copolymer (ethylene content 80mol%, MFR 190℃, 0.80g/10min,
60 parts by weight (density 0.87 g/cm ³ , crystallinity 15%), 0.05 α,α′-bis-t-butylperoxy-p-diisopropylbenzene dissolved in a small amount of acetone.
parts by weight and 1.0 part by weight of maleic anhydride were blended in a Henschel mixer. This blend was extruded into pellets at 230°C using the extruder used in Example 1 to obtain a modified polyolefin. Thereafter, 100 parts by weight of the polyamide of Example 1 and 25 parts by weight of the modified polyolefin were dry blended. The following steps were carried out in the same manner as in Example 1. Table 1 shows the results.
It was shown to.

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Claims (1)

[Claims] 1. Polyamide (A), modified crystalline ethylene polymer
A polyamide composition comprising (B) and an α-olefin elastomer (C), wherein the composition of each component in the composition is such that the modified crystal is ethylene-based polymer (B) in a range of 1 to 200 parts by weight,
The α-olefin elastomer (C) is 1 or more.
100 parts by weight, [] the modified crystalline ethylene polymer (B) is a crystalline ethylene polymer containing ethylene as a main component;
It is obtained by graft copolymerizing 0.01 to 10 parts by weight of unsaturated carboxylic acid or its derivative component units to 100 parts by weight, and the crystallinity is 50.
% or more, and the melt flow rate at 190℃ [MFR190℃] is 0.01 to 50
g/10min, [] the α-olefin elastomer (C) is within the range of α-
The main component is an olefin component unit, the crystallinity is in the range of 40% or less, and the melt flow rate at 190°C [MFR190°C] is in the range of 0.01 to 50 g/10 min; A polyamide composition characterized by: