JPH0414136B2 - - 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. 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, Japanese Patent Application Laid-Open No. 57-8246 discloses that crystalline polyolefin and low-crystalline ethylene.
A method of blending a graft modified composition with an α-olefin copolymer has been proposed. but,
In this method, the modified polyolefin in the graft modified product and the modified low-crystalline ethylene α
- It is difficult to control the melt fluidity of each olefin copolymer, and as a result, it is impossible to obtain a polyamide composition with good dispersibility, and the temperature range for improving impact resistance is significantly narrowed, and the improvement effect is also small. However, there are disadvantages in that the low-temperature isot impact strength and falling weight impact strength, particularly at temperatures below -20 DEG C., are significantly reduced, and the melt flowability of the composition is also reduced. 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 If we consider the effect of improving the impact resistance of polyamide compositions obtained when the composition with the copolymer is changed, 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 improvement effect was 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. The present inventors investigated the development of polyamide compositions with excellent performance, and found that a modified low-crystalline ethylene/α-olefin copolymer (B) and a low-crystalline ethylene/α-olefin/diene copolymer ( C) in a specific range to form a composition, the modified low-crystalline ethylene/α-olefin copolymer can improve the impact resistance of the polyamide composition. It was discovered that there is a synergistic effect between the combination of the polymer and the low-crystalline ethylene/α-olefin diene copolymer, and it is not just a reduction in the amount of the modified low-crystalline ethylene/α-olefin copolymer used. , arrived at the present invention. 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, and resistance to water absorption and salt water decomposition under salt water conditions. In addition, this composition has excellent molding processability because there is little decrease in melt flowability. To summarize the present invention, the present invention comprises polyamide
(A), a modified low-crystalline ethylene/α-olefin copolymer (B), and a low-crystalline ethylene/α-olefin/diene copolymer (C), the polyamide composition comprising: The composition of each component is such that the modified low-crystalline ethylene/α-olefin copolymer (B) is 1 to 100 parts by weight of the polyamide (A).
100 parts by weight, and the low crystalline ethylene/α-olefin diene copolymer (C) is in the range 1 to 100 parts by weight, [] the modified low crystalline ethylene/α-olefin copolymer (C) The polymer (B) contains 0.01 to 10 parts by weight of an unsaturated carboxylic acid or its derivative component unit per 100 parts by weight of a base low-crystalline ethylene/α-olefin copolymer mainly composed of ethylene component units. The 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 low crystalline ethylene/α-olefin/
The diene copolymer (C) contains diene component units in an amount of 0.05 to 15 mol%, has a crystallinity of 40% or less, and has a temperature of 135°C.
The gist of the invention is a polyamide composition characterized in that the intrinsic viscosity [η] in decalin is in the range of 0.5 to 7 dl/g. 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. 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 dodecanoamino (6.12 nylon). ),
There are polybis(4-aminocyclohexyl)methandodecanamides, or polyamides prepared by ring opening of 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 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 low-crystalline ethylene/α-olefin copolymer (B) blended into the polyamide composition of the present invention is
Low-crystalline ethylene with ethylene as its main component.
Graft copolymerized with 0.01 to 10 parts by weight of unsaturated carboxylic acid or its derivative component units to 100 parts by weight of α-olefin copolymer,
Its crystallinity is in the range of 40% or less, and 135
It is necessary that the intrinsic viscosity [η] _B in decalin at ℃ is in the range of 0.5 to 7 dl/g, and in addition, the base material is a low-crystalline ethylene/α-olefin copolymer containing ethylene as the main component. unsaturated carboxylic acid or its derivative component unit per part
Graft copolymerized in the range of 0.05 to 5 parts by weight, the crystallinity is in the range of 1 to 30%, and the intrinsic viscosity [η] _B in decalin at 135°C is in the range of 0.7 to 5 dl/g. It is preferable that the Furthermore, the modified low crystalline ethylene α-
Other physical properties of the olefin copolymer (B) include a molecular weight distribution (w/n) of usually 1.5 to 50, preferably 2.
to 30, and the glass transition temperature is usually -
It is in the range of 10°C or lower, preferably -20°C or lower.
If the grafting ratio of the unsaturated carboxylic acid or its derivative component unit in the modified low-crystalline ethylene/α-olefin copolymer is less than 0.01 part by weight, the compatibility with the polyamide composition will be poor and the impact strength of the polyamide composition will deteriorate. If the amount exceeds 10 parts by weight, the degree of crosslinking of the graft modified product will increase, and even if it is blended into polyamide, the effect of improving the impact resistance of the composition will decrease. When the degree of crystallinity of the modified low-crystalline ethylene/α-olefin copolymer exceeds 40%, the impact strength of the polyamide composition decreases, and when the intrinsic viscosity thereof becomes lower than 0.5 dl/g, The impact strength of the polyamide composition decreased by 7 dl/
If it is larger than g, poor dispersion will occur, resulting in a decrease in impact resistance and a decrease in melt fluidity. The base polymer constituting the modified low-crystalline ethylene/α-olefin copolymer is a copolymer of ethylene and an α-olefin other than ethylene, and is a copolymer mainly composed of ethylene, It is a low-crystalline ethylene/α-olefin copolymer.
Its ethylene content is usually in the range of 95 to 50 mol%, preferably 93 to 55 mol%, its crystallinity is usually in the range of 40% or less, preferably 30% or less, and its intrinsic viscosity [η] is usually in the range of 0.5 to 7 dl/g, preferably 0.7 to 5 dl/g, and its glass transition temperature is usually -10°C or lower,
Preferably it is in the range of -20°C or lower. The α-olefin component units other than ethylene constituting the low-crystalline ethylene/α-olefin copolymer include:
Examples include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-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 ethylene/α-olefin copolymer (B) is as follows:
For example, acrylic acid, methacrylic acid, α-ethyl acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, methyltetraphhydrophthalic acid, endocis-bicyclo[2.2.1]hept-5-ene -2,3-dicarboxylic acid (nadic acid), methyl-endocys-bicyclo[2.2.1]hept-5-ene-2,3
-Unsaturated dicarboxylic acids such as dicarboxylic acid (methylnadic acid), derivatives of unsaturated dicarboxylic acids such as acid halides, amides, imides, acid anhydrides, and esters of the unsaturated dicarboxylic acids, specifically, chlorinated Examples include maleyl, 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 ethylene/α-
Various conventionally known methods can be employed to produce the modified low-crystalline ethylene/α-olefin copolymer by graft copolymerization with the olefin copolymer. For example, low crystalline ethylene α
- There is a method of melting the olefin copolymer and adding a graft monomer to carry out graft copolymerization, or a method of dissolving the olefin copolymer in a solvent 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. Grafting reactions are usually
It is carried out at a temperature of 60 to 350°C. The ratio of radical initiator used is usually 0.01 to 20 parts by weight per 100 parts by weight of the low-crystalline ethylene/α-olefin copolymer.
Parts by weight range. Examples of the radical initiator include organic peroxides, organic peresters, and azo compounds. Low-crystalline ethylene/α-olefin/diene copolymer (C) blended into the polyamide composition of the present invention
has a crystallinity of 40% or less and an intrinsic viscosity [η] in decalin at 135°C.
It is necessary that the crystallinity is in the range of 0.5 to 7 dl/g, and furthermore, the crystallinity is in the range of 30% or less, and the intrinsic viscosity [η] is 0.7 to 5.
It is preferably in the range of dl/g. Regarding other physical properties of the low-crystalline ethylene/α-olefin/diene copolymer, the content of ethylene component units is usually 95 to 30 mol%, preferably 90 to 35 mol%, and α-olefin component units. The content is usually in the range of 5 to 70 mol%, preferably 10 to 65 mol%. Diene component unit is 0.05 or more
15 mol%, preferably in the range 0.5 to 10 mol%. The glass transition temperature is usually -10°C or lower, preferably -20°C or lower. When the degree of crystallinity of the low-crystalline ethylene/α-olefin/diene copolymer is higher than 40%, the effect of improving the impact resistance of the polyamide composition decreases. Also,
The intrinsic viscosity of the low crystalline ethylene/α-olefin/diene copolymer in decalin at 135°C is
If it is less than 0.5 dl/g, the impact resistance of the polyamide composition will decrease, and if it exceeds 7 dl/g, the impact resistance and melt flowability of the polyamide composition will decrease. here,
The α-olefin component units are α-olefins other than ethylene, such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene,
Examples include 1-hexene, 1-octene, and 1-dodecene. Diene component units include 1,4-hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, 2,5
Examples include non-conjugated diene components such as -norbonadiene, and conjugated diene components such as butadiene, isoprene, and piperylene. Examples of the low crystalline ethylene/α-olefin/diene copolymer include ethylene/propylene/1,4-hexadiene copolymer, ethylene/propylene/dicyclopentadiene copolymer, ethylene/propylene/dicyclopentadiene copolymer, and ethylene/propylene/dicyclopentadiene copolymer.
5-ethylidene-2-norbornene copolymer, ethylene propylene norbonadiene copolymer,
Examples include ethylene/1-butene/dicyclopentadiene copolymer and ethylene/1-butene/5-ethylidene-2-norbornene copolymer. In the polyamide composition of the present invention, the modified low crystalline ethylene/α-olefin copolymer (B) and the low crystalline ethylene/α-olefin diene copolymer (C) are blended into the polyamide (A). When doing so,
Intrinsic viscosity of both decalin at 135℃ [η]
It is preferable to adjust the value of the ratio, [η] _B / [η] _C , to a range of usually 0.1 to 10, more preferably 0.2 to 5. In the polyamide composition of the present invention, the blending ratio of the modified low-crystalline ethylene/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. If the blending ratio of the modified low-crystalline ethylene/α-olefin copolymer exceeds 100 parts by weight, the rigidity and melt flowability of the polyamide composition will decrease, and if it becomes less than 1 part by weight, the polyamide composition will deteriorate. The impact resistance, stress crack resistance and water resistance of the product will decrease. Further, the blending ratio of the low crystalline ethylene/α-olefin/diene copolymer (C) to 100 parts by weight of the polyamide (A) needs to be in the range of 1 to 100 parts by weight, and more preferably. is in the range from 5 to 80 parts by weight, particularly preferably from 5 to 50 parts by weight. The low crystalline ethylene/α-olefin/
If the blending ratio of the diene copolymer exceeds 100 parts by weight, the rigidity and melt flowability of the polyamide composition will decrease, and if it becomes less than 1 part by weight, the impact resistance and stress crack resistance of the polyamide composition will decrease. properties and water resistance will decrease.
Furthermore, in the polyamide composition of the present invention, the modified low-crystalline ethylene/α-olefin copolymer
(B) The above low crystalline ethylene α per 100 parts by weight
- The blending ratio of the olefin-diene copolymer (C) is usually 5 to 2000 parts by weight, preferably 10 to 1500 parts by weight.
Parts by weight range. Furthermore, in the polyamide composition of the present invention, the modified low-crystalline ethylene
The ratio of the graft copolymerized unsaturated carboxylic acid or its derivative component unit to the total amount of the α-olefin copolymer (B) and the low-crystalline ethylene/α-olefin/diene copolymer (C) is usually
It ranges from 0.02 to 7% by weight, preferably from 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 also be added at any of these stages, if necessary. The polyamide composition of the present invention has excellent properties such as rigidity, impact resistance, and water resistance. Among these, the composition obtained by melt-mixing the polyamide (A) component into a premix obtained by preliminary melt-mixing of the (B) component and (C) component has particularly high 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 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 Examples and Comparative Examples, the crystallinity degree and the intrinsic viscosity [η] were measured 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 modified ethylene/propylene copolymer [propylene content 20 mol%, [η] 2.45 dl/
g, density 0.86 g/cm ³ , crystallinity 14%, maleic anhydride unit content: based on 100 parts by weight of base copolymer
1.0 parts by weight] and ethylene-propylene-diene copolymer [propylene content 37 mol%, ENB content 2.3
mol%, [η] 1.53 dl/g, density 0.86 g/cm ³ , crystallinity 11%] was adjusted to the proportions shown in Table 1.
Premixing was carried out using a mmφ extruder (L/D=28, 230°C). Next, this premix and nylon 6
[Manufactured by Toray Industries, Inc., Amiran CM1021XF, MFR3.74g/
10 min, Q condition] 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/D28, 30 mmφ) set at 260°C to prepare a melt blend (pellet shape). the pellets
After vacuum drying at 100° C. for one day and night, injection molding was performed under the following conditions to produce specimen 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: ASTM D using a 1/8″ thick test piece
-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 1/8″ thickness test,
-40°C notched isot impact strength was measured according to ASTM D256. The conditioning of the specimen is 23
The test was carried out for 3 days in a constant temperature and humidity room at 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. The results are shown in Table 1. Examples 2 to 12, Comparative Examples 1 to 4 Modified low crystalline ethylene/α-olefin copolymer (B) and low crystalline ethylene/α-olefin copolymer (B) shown in Table 1
A blend was prepared in the same manner as in Example 1, except that the olefin-diene copolymer (C) was used in the proportions shown in Table 1, and its physical properties were measured. The results are shown in Table 1. In addition, modified low-crystalline ethylene/α-olefin copolymer (B) and low-crystalline ethylene/α-olefin copolymer (B)
Table 1 also shows the physical properties of the polyamide when the olefin-diene copolymer (C) was not blended (Comparative Example 1).

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Claims (1)

[Claims] 1. Polyamide (A), modified low crystalline ethylene α-
Olefin copolymer (B) and low crystalline ethylene
A polyamide composition containing an α-olefin/diene copolymer (C), wherein the composition of each component in the composition is such that the modified low-crystalline ethylene is added to 100 parts by weight of the polyamide (A).・α-olefin copolymer (B) is 1 or more
100 parts by weight, and the low crystalline ethylene/α-olefin diene copolymer (C) is in the range 1 to 100 parts by weight, [] the modified ethylene/α-olefin copolymer (C) B) is a base low-crystalline ethylene/α-olefin copolymer whose main component is ethylene unit.
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 to 100 parts by weight, and its crystallinity is 40.
% or less, and the intrinsic viscosity [η] in decalin at 135°C is 0.5 to 7 dl/g
and [] the low crystalline ethylene/α-olefin/
The diene copolymer (C) contains diene component units in an amount of 0.05 to 15 mol%, has a crystallinity of 40% or less, and has a temperature of 135°C.
A polyamide composition characterized in that the intrinsic viscosity [η] in decalin is in the range of 0.5 to 7 dl/g.