JPH0414137B2 - - 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, appearance, 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 the falling weight impact strength at low temperatures is also 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. 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-56-109427, 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 product of a 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 modified ethylene/α-olefin elastic copolymer in the graft modified product due to crosslinking, and as a result, a polyamide composition with good dispersibility is obtained. The temperature range for improving impact resistance becomes significantly narrower, and the improvement effect is small, especially at -20
There are disadvantages in that the low-temperature Izot impact strength and falling weight impact strength at temperatures below .degree. C. are significantly lowered, and the melt fluidity of the composition is also lowered. Furthermore, in the prior art document, JP-A-55-
Publication No. 36279 describes the use of modified low-crystalline ethylene to improve the impact resistance of polyamide, as mentioned above.
When blending an α-olefin copolymer, if an unmodified low-crystalline ethylene/α-olefin copolymer is further blended, a polyamide composition with excellent appearance and color tone can be obtained. It is also described that the use ratio of the low-crystalline ethylene/α-olefin copolymer can be reduced, so that it has excellent economic effects. However, according to the description of the publication, especially the description of Examples and Comparative Examples, it is clear that modified low-crystalline ethylene/α-olefin copolymer and unmodified low-crystalline ethylene/α-olefin copolymer blended into polyamide Considering the effect of improving the impact resistance of polyamide compositions obtained by changing the composition with the copolymer, unmodified low-crystalline ethylene α-
An improvement in impact resistance was observed compared to the experiment in which the olefin copolymer was blended alone (Comparative Example 1), but the experiment in which the modified low-crystalline ethylene/α-olefin copolymer was blended alone (Reference Example) ), its impact resistance is higher than that of modified low-crystalline ethylene α-
The impact resistance is only improved in proportion to the blending ratio of the olefin copolymer, and economic effects are achieved by reducing the amount of the modified low-crystalline ethylene/α-olefin copolymer used. It's just that. Furthermore, in terms of appearance, it has the disadvantage of uneven gloss. As a result of studying the development of polyamide compositions with excellent performance, the present inventors discovered that modified low-crystalline propylene/α-olefin copolymer and ethylene/α-olefin copolymer
- By blending an olefin-based elastic polymer with a polyamide in a specific range to form a composition, the modified low-crystalline propylene and α
- A synergistic effect exists in the blending of the olefin copolymer and the ethylene/α-olefin elastic polymer,
The present invention was achieved by discovering that the present invention is not only effective in reducing the amount of modified low-crystalline propylene/α-olefin copolymer used. According to the present invention, the polyamide composition of the present invention has improved impact resistance such as isot impact strength and falling weight impact strength at low temperatures, stress crack resistance, water absorption, salt water decomposition resistance under salt water conditions, etc. The water resistance of the composition is significantly improved, the appearance, that is, the gloss is uniform, and the composition exhibits excellent moldability because there is little decrease in melt flowability. To summarize the present invention, the present invention comprises polyamide
A polyamide composition comprising (A), a modified low-crystalline propylene/α-olefin copolymer (B), and an ethylene/α-olefin elastomer (C), each component in the composition The composition of the modified low crystalline propylene/α-olefin copolymer (B) is 1 to 100 parts by weight of the polyamide (A).
100 parts by weight, and the α-olefin elastomer (C) is in the range of 1 to 100 parts by weight; [] the modified low-crystalline propylene/α-olefin copolymer (B) is , an unsaturated carboxylic acid or its derivative component based on 100 parts by weight of the base low-crystalline propylene/α-olefin copolymer containing propylene component units as the main component in an amount of more than 50 mol% and less than 90 mol%. The unit is graft copolymerized in the range of 0.01 to 10 parts by weight, the crystallinity is in the range of 40% or less, and the intrinsic viscosity [η] in decalin at 135°C is in the range of 0.5 to 7 dl/g. and [] the ethylene/α-olefin elastomer (C) contains 63 mol% of ethylene component units as the main component.
or more, the crystallinity is in the range of 40% or less, and the intrinsic viscosity [η] in decalin at 135°C is in the range of 0.5 to 7 dl/g. The gist of the invention is a polyamide composition having the following characteristics. The polyamide (A) used in the polyamide composition of the present invention is of sufficient molecular weight to produce molded articles, and is composed of a saturated organic dicarboxylic acid having 4 to 12 carbon atoms and a saturated organic dicarboxylic acid having 2 to 13 carbon atoms. It can be produced by condensing equimolar amounts of organic diamines having atoms. Here, if necessary, diamine can be used in the polyamide so that the amino group ends are in excess compared to the carboxyl group ends, or conversely, dicarboxylic acid can be used so that the carboxyl groups are in excess. can. Similarly, these polyamides can also be produced from derivatives that produce the amine and acid, such as esters, acid hydrates, amine salts, and derivatives that produce the amine. 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 polyhexamethyleneandipamide (6.6 nylon), polyhexamethylene azelamide (6.9 nylon), polyhexamethylene sebaamide (6.10 nylon) and polyhexamethylene dodecanoamide (6.12 nylon),
There are polyamides prepared by ring opening of polybis(4-aminocyclohexyl)methandodecanoamide or lactams, namely polycaprolactam (6nylon), polylauritulactam or poly-11-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. a. It is also possible to use blends of polyamides such as nylon 6.6 and mixtures of nylon 6. The condensed polyamide used in the present invention is preferably
Polyhexamethylene adipamide (6.6 nylon)
or polyhexamethylene azelamide (nylon 6.9) and polycaprolactam (nylon 6)
It is. Modified low-crystalline propylene/α-olefin copolymer (B) blended into the polyamide composition of the present invention
is obtained by graft copolymerizing unsaturated carboxylic acid or its derivative component units in the range of 0.01 to 10 parts by weight to 100 parts by weight of a base low-crystalline propylene/α-olefin copolymer containing propylene as the main component. and its crystallinity is in the range of 40% or less,
and the intrinsic viscosity in decalin at 135°C [η] _B
It is necessary that the amount is in the range of 0.5 to 7 dl/g, and furthermore, the base material is a low crystalline propylene/α-olefin copolymer 100 containing propylene as the main component.
Graft copolymerized with unsaturated carboxylic acid or its derivative component units in the range of 0.02 to 5 parts by weight, and its crystallinity is 1 to 30%.
It is preferable that the intrinsic viscosity [η] _B in decalin at 135° C. be in the range of 0.7 to 5 dl/g. Furthermore, other physical properties of the modified low-crystalline propylene/α-olefin copolymer (B) include a molecular weight distribution (w/n) of usually 1.5 to 1.
50, preferably in the range of 2 to 30, and the glass transition temperature is usually -5°C or lower, preferably -20°C or lower. The modified low crystalline propylene α
- If the grafting ratio of the unsaturated carboxylic acid or its derivative component unit in the olefin copolymer is less than 0.01 part by weight, the compatibility with polyamide is poor, and the impact strength of the polyamide composition is reduced;
When the amount exceeds 10 parts by weight, the impact strength tends to decrease. The modified low crystalline propylene α
- When the degree of crystallinity of the olefin copolymer becomes greater than 40%, the impact resistance of the polyamide composition decreases, and when its intrinsic viscosity becomes less than 0.5 dl/g, the impact resistance of the polyamide composition decreases. If it exceeds 7 dl/g, impact resistance and melt fluidity will decrease due to poor dispersion. The base polymer constituting the modified low-crystalline propylene/α-olefin copolymer is a copolymer of propylene and an α-olefin other than propylene, and is a copolymer mainly composed of propylene,
It is a propylene/α-olefin copolymer with low crystallinity. Its propylene content ranges from >50 to 90 mol%, preferably >50 to 80 mol%. Also, the crystallinity of the base polymer is usually 40%
below, preferably within the range of 30%, and at 135℃
The intrinsic viscosity [η] in decalin is usually 0.5.
The glass transition temperature is usually in the range of -5°C or lower, preferably -20°C or lower. The α-olefin component units other than propylene constituting the low-crystalline propylene/α-olefin copolymer include ethylene, 1-butene, 1-pentene,
4-methyl-1-pentene, 1-hexene, 1-
Examples include octene, 1-decene, and 1-dodecene. The unsaturated carboxylic acid or its derivative component unit of the graft monomer component constituting the modified low-crystalline propylene/α-olefin copolymer (B) includes, for example, acrylic acid, methacrylic acid, α-
Ethyl acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, endosys-
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,
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. The graft monomer selected from the unsaturated carboxylic acid or its derivative is combined with low crystalline propylene α.
Various conventionally known methods can be employed to produce the modified low-crystalline propylene/α-olefin copolymer by graft copolymerization with the -olefin copolymer. For example, there is a method of melting a low-crystalline propylene/α-olefin copolymer and adding a graft monomer to carry out graft copolymerization, or a method of dissolving a low-crystalline propylene/α-olefin copolymer and adding a graft monomer to carry out graft copolymerization. In any case, in order to efficiently graft copolymerize the graft monomer, it is preferable to carry out the reaction in the presence of a radical initiator. The grafting reaction is usually carried out at a temperature of 60 to 350°C. The ratio of radical initiator used is low crystalline propylene/α-
Usually 0.01 per 100 parts by weight of olefin copolymer
and 100 parts by weight. As a radical initiator, organic peroxide, organic perester,
Examples include azo compounds. The ethylene/α-olefin elastic polymer (C) blended into the polyamide composition of the present invention has ethylene as its main component and has a crystallinity of 40%.
The intrinsic viscosity [η] in decalin at 135°C must be in the range of 0.5 to 7 dl/g, and the crystallinity must be in the range of 30% or less, The intrinsic viscosity [η] _C in decalin at 135°C must be in the range of 0.5 to 7 dl/g, and furthermore, the degree of crystallinity must be in the range of 30% or less, and the The intrinsic viscosity [η] _C in decalin is
Preferably it is in the range of 0.7 to 5 dl/g.
Regarding other physical properties of the α-olefin elastic polymer, the glass transition temperature is usually -5°C or lower;
Preferably it is in the range of -20°C or lower. When the degree of crystallinity of the α-olefin elastomer polymer exceeds 40%, the effect of improving the impact resistance of the polyamide composition decreases. In addition, when the intrinsic viscosity [η] of the α-olefin-based elastic polymer in decalin at 135°C becomes smaller than 0.5 dl/g, the impact resistance of the polyamide composition decreases,
If it exceeds 7 dl/g, the impact resistance and melt flowability of the polyamide composition will decrease. Here, as the α-olefin component unit,
Examples include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, and 1-dodecene. The ethylene/α-olefin-based elastic polymer is usually composed of a mixed component of two or more α-olefin components, and in addition to these α-olefin component units, it also contains a small amount of other copolymerizable components. There's no harm in it. Copolymerizable α
- Components other than olefin include non-conjugated diene components such as 1,4-hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, and 2,5-norbonadiene, and conjugated diene components such as butadiene, isoprene, and piperylene. I can give an example. The content of ethylene component units constituting the ethylene/α-olefin elastic polymer is in the range of 63 mol% or more, preferably 85 mol% or more, particularly preferably 90 mol% or more. Examples of the ethylene/α-olefin elastic polymer include ethylene/propylene copolymer, ethylene/1-butene copolymer, ethylene/4-methyl-1-pentene copolymer, and ethylene/1-hexene copolymer. , 2-component ethylene/α-olefin elastic copolymers such as ethylene/1-octene copolymer, ethylene/1-decene copolymer, ethylene/propylene/1,4-hexadiene copolymer, ethylene/propylene・Ternary ethylene/α- such as dicyclopentadiene copolymer, ethylene/propylene/ethylidenenorbornene copolymer, ethylene/propylene/norbornadiene copolymer, etc.
Examples include olefin/non-conjugated diene elastic copolymers. Among these ethylene/α-olefin elastomeric polymers, two-component ethylene/α-olefin elastomeric polymers are preferred. In the polyamide composition of the present invention, when blending the modified low-crystalline ethylene/α-olefin copolymer (B) and the ethylene/α-olefin elastic polymer (C) with the polyamide, both The ratio of intrinsic viscosity [η] in decalin at 135°C, [η] ^B /[η] ^C , is usually adjusted to a range of 0.1 to 10, and preferably adjusted to a range of 0.2 to 5. In the polyamide composition of the present invention, the blending ratio of the modified low-crystalline propylene/α-olefin copolymer (B) to 100 parts by weight of the polyamide (A) must be in the range of 1 to 100 parts by weight. The amount is more preferably 5 to 80 parts by weight, particularly preferably 5 to 50 parts by weight.
When the blending ratio of the modified low-crystalline propylene/α-olefin copolymer is greater than 100 parts by weight,
The rigidity and melt flowability of the polyamide composition decrease, and when the amount is less than 1 part by weight, the impact resistance, stress crack resistance, and water resistance of the polyamide composition decrease, and the effect of improving gloss unevenness decreases. I come to do it. In addition, the polyamide (A)
The blending ratio of the ethylene/α-olefin elastomer (C) to 100 parts by weight must be in the range of 1 to 100 parts by weight, more preferably 5 to 80 parts by weight, particularly preferably 5 to 80 parts by weight. In the range of 50 parts by weight. When the blending ratio of the ethylene/α-olefin elastomer exceeds 100 parts by weight, the rigidity and melt flowability of the polyamide composition decreases, and when it decreases below 1 part by weight, the impact resistance of the polyamide composition decreases. properties, stress crack resistance and water resistance. Furthermore, in the polyamide composition of the present invention, the ethylene/
The blending ratio of the α-olefin elastomer (C) is usually 5 to 2000 parts by weight, preferably 10 to 1500 parts by weight. Furthermore, in the polyamide composition of the present invention, the modified low crystalline propylene
α-olefin copolymer (B) and the ethylene
The proportion of the graft-copolymerized unsaturated carboxylic acid or derivative unit thereof based on the total amount of the α-olefin elastomer (C) is generally in the range of 0.02 to 7% by weight, preferably 0.05 to 5% by weight. In addition to the above-mentioned three essential components, the polyamide composition of the present invention may optionally contain antioxidants, ultraviolet absorbers, photoprotectants, phosphite stabilizers, peroxide decomposers, basic adjuvants, Contains fillers such as nucleating agents, plasticizers, lubricants, antistatic agents, flame retardants, pigments, dyes, carbon black, asbestos, glass fibers, potassium titanate whiskers, mica, carrion, talc, silica, and silica alumina. It is also possible to do so. 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, two essential components may be premixed and then mixed with the remaining components, or three essential components may be mixed with other remaining components at the same time. Moreover, the above-mentioned additives, such as antioxidants, can be added at any of these stages as necessary. The polyamide composition of the present invention has excellent properties such as rigidity, impact resistance, and water resistance. Among them, the composition obtained by melt-mixing the polyamide (A) component into a premix prepared by melt-mixing the components (B) and (C) in particular has particularly good performance. is excellent. The melt flowability [melt flow rate (MFR, 235°C, 1000g load)] of the composition of the present invention is usually 0.1
to 500g/10min, preferably 0.2 to 100
The range is g/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 for 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, the degree of crystallinity and the intrinsic viscosity [η] were determined by the following method. Crystallinity: Determined by X-ray diffraction at 23°C. Intrinsic viscosity [η]: Determined in decalin at 135°C. Example 1 Maleic anhydride grafted propylene/ethylene copolymer [propylene content 60 mol%, [η] 1.54
dl/g, density 0.86 g/cm ³ , crystallinity 5%, maleic anhydride unit content 0.5 parts by weight per 100 parts by weight of base copolymer] and ethylene/1-butene copolymer [ethylene content 90 Mol%, [η] 2.31dl/g, density
0.88 g/cm ³ , crystallinity 17%] were premixed in a 30 mmφ extruder (L/D=28, 230° C.) to the proportions shown in Table 1. Next, this premix and nylon 6 (manufactured by Toray Industries, Inc., Amiran CM1021XF,
MFR 3.74g/10min, Q conditions) were mixed in the proportions shown in Table 1 to prepare a dry blend consisting of two types of pellets. Furthermore, it is fed to a single screw extruder (L/D28, 30mmφ) set at 260℃,
A melt blend (pellet form) was prepared. 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: MFR under ASTM D-1238-79Q conditions
was measured. Bending test: using a 1/8″ thick test piece, ASTM D
-790-80, the flexural modulus FM (Kg/cm ² ) and flexural yield strength FS (Kg/cm ² ) were measured. 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. Izotsu impact strength: using a 1/8″ thick test piece,
-40°C notched isot impact strength was measured according to ASTM D256. Conditioning the specimen
The test was carried out for 3 days in a constant temperature and humidity room at 23℃ 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℃ for 24 hours, then subjected to a water absorption test in water at 50℃ for 48 hours, and the water absorption rate ( %) was calculated. Gloss unevenness: The gloss unevenness of the injection molded product was visually determined. The results are shown in Table 1. Examples 2 to 12, Comparative Examples 1 to 4 The modified low-crystalline propylene/α-olefin copolymer (B) and the α-olefin elastomer (C) shown in Table 1 were mixed in the proportions shown in Table 1. A blend was prepared in the same manner as in Example 1 except that the blend was used, and the physical properties were measured. The results are shown in Table 1. In addition, Table 1 also shows the physical properties of the polyamide when the modified low-crystalline propylene/α-olefin copolymer (B) and the α-olefin elastic polymer (C) were not blended (Comparative Example 1). .

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Claims (1)

[Claims] 1. Polyamide (A), modified low-crystalline propylene α
- A polyamide composition comprising an olefin copolymer (B) and an ethylene/α-olefin elastic copolymer (C), wherein the composition of each component in the composition is such that the polyamide (A) 100 The amount of the modified low-crystalline propylene/α-olefin copolymer (B) is 1 to 1% by weight.
100 parts by weight, and the ethylene/α-olefin elastic copolymer (C) is in the range of 1 to 100 parts by weight, [] the modified low-crystalline propylene/α-olefin copolymer ( B) is an unsaturated carboxylic acid or its It is obtained by graft copolymerizing derivative component units in the range of 0.01 to 10 parts by weight, the degree of crystallinity is in the range of 40% or less, and the intrinsic viscosity [η] in decalin at 135°C is 0.5 to 7.
dl/g, and [] the ethylene/α-olefin elastic copolymer (C) contains 63 mol% or more of ethylene component units as the main component; Crystallinity is in the range of 40% or less, and
The intrinsic viscosity [η] in decalin at 135℃ is
A polyamide composition, characterized in that it is in the range of 0.5 to 7 dl/g.