JPS59135251A - Polyamide composition - Google Patents

Abstract

PURPOSE:To provide a polyamide compsn. having excellent rigidity, moldability and resistance to low-temperature impact and brine, by blending a modified lowly crystalline ethylene/alpha-olefin copolymer and an ethylene/vinyl acetate copolymer with a polyamide in a specified ratio. CONSTITUTION:A polyamide compsn. contains 100pts.wt. polyamide (A), 1- 100pts.wt. modified lowly crystalline ethylene/alpha-olefin copolymer (B) and 1- 100pts.wt. ethylene/vinyl acetate copolymer (C), said copolymer B having a crystallinity index of 40% or below and an MFR 190 deg.C of 0.01-50g/10min and being obtd. by graft copolymerizing 0.01-10pts.wt. unsaturated carboxylic acid (derivative) unit onto 100pts.wt. lowly crystalline ethylene/alpha-olefin copolymer base mainly composed of ethylene monomer unit and said copolymer C being mainly composed of ethylene and having a crystallinity index of 0-60% and an MFR 190 deg.C of 0.01-100g/10min.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides rigidity 1. Excellent low-temperature impact resistance and salt water resistance 1.
The present invention also relates to a polyamide resin composition and composition having excellent moldability and formability. , .

Due to their excellent physical properties, polyamide resins are expected to be in great demand in 1) re-engineering plastics and 7). It has sufficient performance such as durability, low-temperature impact resistance, water resistance, salt water resistance, etc., and impact resistance such as crystal impact strength. For example, as a method to improve the sex,
5 Publication A6, Special Publication No. 55-44 i Q8,
JP-A No. 5-9'661, JP-A-55-9662
In prior art documents such as Japanese Patent No.
β = Ethylene grafted with unsaturated carboxylic acid α-
A method of blending a modified α-olefin elastic polymer such as an olefin copolymer has been proposed. All of the compositions proposed in these prior art documents improve impact resistance such as Izotz impact strength. In addition to greatly reducing the I properties, the falling weight impact strength at low temperatures is also insufficient, and it is difficult to obtain a molded bag with high rigidity and high impact strength using these compositions. In addition, these compositions are often too easy to use due to their poor flowability.
Depending on the molding method, there is also the drawback that molding processability is reduced. 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. There are also restrictions on its use.

In addition, as a method of improving water resistance such as hygroscopicity or salt water resistance of polyamide resin, Japanese Patent Application Laid-Open No.
-80014 Publication, JP-A-56-16.77.5 J
No. 1, JP-A-56-109247 1. Japanese Patent Application Publication No. 5
Publication No. 6-157.151 discloses that boria
A method has been proposed in which a neutralized ethylene/α,β-unsaturated monocarboxylic acid copolymer (ionomer resin', )' is blended as a component. 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. .

As a method for improving the stiffness of polyamide resin compositions,
Publication No. 2at describes clean-skinned polio, lefin and ethylene.
A method of blending an α-merefin elastic copolymer and a graft modified product of nine compositions has been proposed. However, with this method, it is difficult to control the melt fluidity of the modified IJ olefin 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 cannot be obtained. is no longer obtained, the temperature range for improving impact resistance becomes significantly narrower, and the improvement effect is also small.
In particular, the low-temperature isot impact strength and falling weight impact strength at temperatures below -20 DEG C. are significantly lowered, and the melt fluidity of the composition is also lowered.・Furthermore, among the prior art documents mentioned above, Japanese Patent Application Laid-Open No. 55-362
No. 79 discloses that when blending a modified low-crystalline ethylene/α-olefin copolymer to improve the impact resistance of polyamide, as mentioned above, an unmodified low-crystalline ethylene/α-olefin copolymer is added. By blending the electropolymer together, a polyamide composition with excellent appearance and color tone can be obtained, and the proportion of expensive modified low-crystalline ethylene/α-olefin copolymer used can be reduced, resulting in economical effects. It is also stated that it is excellent. however,
According to the description of the publication, especially the description of Examples and Comparative Examples, modified low crystalline ethylene α-olefin copolymer □ and unmodified low crystalline ethylene α-olefin copolymer □ are blended into polyamide. Considering the effect of improving the impact resistance of polyamide compositions obtained by changing the composition with one olefin copolymer, it is important to consider that when a single unmodified low-crystalline ethylene/modified olefin copolymer is blended alone. experiment'(
An improvement in impact resistance is observed compared to Comparative Example 1), but compared to an experiment (reference example) in which the modified low-crystalline ethylene/α-olefin copolymer was blended alone, the impact resistance was lower than that of the modified The impact resistance is only improved in proportion to the blending ratio of the low-crystalline ethylene/α-olefin copolymer.
□ Economic effects have only been achieved by reducing the amount of the modified low-crystalline ethylene/α-olefin copolymer used.

As a result of studying the development of a polyamide composition with excellent performance, the present inventors determined that the ratio of modified low-crystalline ethylene/α-olefin copolymer and ethylene/vinyl acetate copolymer was within a specific range. Regarding the effect of improving the impact resistance of the polyamide composition by blending it with polyamide to form a composition, the modified low-crystalline ethylene/α-orphine copolymer and the ethylene/vinyl acetate copolymer are blended together. There is a synergistic effect between the simple modified low crystalline ethylene and
The inventors have discovered that the present invention is not only effective in reducing the amount of α-olefin copolymer used, and have 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, water absorption, salt water decomposition resistance under salt water conditions, etc. The water resistance of the composition has been significantly improved, and the composition has excellent moldability because there is little decrease in melt flowability.

To summarize the present invention, the present invention is a polyamide composition comprising polyamide (1), a modified low-crystalline ethylene/α-olefin copolymer (B), and an ethylene/vinyl acetate copolymer (C), 1] The composition of each component in the composition is such that the composition of the polyamide (
The modified low crystalline ethylene α based on 1100 parts by weight of A1
- The olefin copolymer (B) is in the range of 1 to 100 parts by weight, and the ethylene/vinyl acetate copolymer (C) is in the range of 1 to 100 parts by weight, [11]
The modified low crystalline ethylene/a-olefin copolymer (B
) is 0.0 parts by weight of an unsaturated carboxylic acid or G-based derivative component unit per 100 parts by weight of a base low-crystalline ethylene/α-olefin copolymer containing ethylene component units as a main component.
Graft copolymerized in a range of 1 to 10 parts by weight,
Its crystallinity is within the range of 40% and 190°
Melt flow rate at C (M F R190-C
) is in the range of 0.01 to 50 g/iQmin, and [111] the ethylene/vinyl acetate copolymer (C, l are ethylene as main components,
Its crystallinity is in the range of 0 to 60% and 1
Melt flow rate at 90°C) (M F R1
The gist of the invention is a polyamide composition characterized in that 9o-c,l is in the range of 0.01 to 100g/IQmin.

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 from 4 to 12 carbon atoms and a saturated organic dicarboxylic acid having from 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 amine 7-terminus is in excess compared to the carboxyl group, or conversely, dicarboxylic acid can be used so that the carboxyl group is 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, superric acid, sepacic acid and dodecandioic 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), polyhexamethyleneadipamide (6,10
nylon) and polyhexamethylene dodeca/amide (
6,12 nylon), polybis(4-aminocyclohexyl)methandodecanoamide, or polyamides prepared by ring opening of lactams, i.e. polycaprolactam (6,12 nylon), polylauritulactam or poly-11-aminoundecanoic acid. There is. It is also possible to use polyamides produced by polymerization of at least two amines or acids used to produce the abovementioned polyamides, for example polymers made from adipic acid and isophthalic acid and hexamethylene diamine. 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 adipamide (6,9 nylon) and polycaprolactam (6,9 nylon).

The modified low-crystalline ethylene/α-olefin copolymer (B) blended into the polyamide composition of the present invention is a base low-crystalline ethylene/α-olefin copolymer containing ethylene component units as a 100% weight base. 0.01 to 10 parts by weight of unsaturated carboxylic acid or its derivative component units per part of the graft copolymer:, its crystallinity □
is in the range of 40% or less, and the melt flow rate at 190°C [JlFR? 9o-c] is in the range of 0.01 to 50 g/l' Ornin, and furthermore, the base low crystalline ethylene/α-olefin copolymer whose main component is ethylene component unit 100 weight. % of unsaturated carboxylic acid or its derivative component unit in the range of 5 to 5 parts by weight, the crystallinity is in the range of 0 to 35%, and the crystallinity is in the range of 0 to 35%, and Melt flow rate (MF
R19o・c) is 0.05 to 20g/i mouth min
It is preferable that it is in the range of . Furthermore, other physical properties of the modified low-crystalline ethylene/α-olefin copolymer (B) include molecular weight distribution (M NV / 1 is usually 1 to 50
, preferably < is in the range of 1 to 20, and the glass transition humidity is usually -10"C or less, preferably -20"C or less.In the modified low-crystalline ethylene-α-olefin copolymer, When the grafting ratio of the unsaturated carboxylic acid or its derivative component unit is reduced by 0.01 parts by weight, the compatibility with polyamide □ decreases, and the impact strength of the condensate decreases. If the crystallinity of the modified low-crystalline ethylene/α-niolefin copolymer exceeds 40%, the impact strength of the polyamide composition will decrease. When the melt flow rate □ becomes smaller than 710 ml, the foil layer strength and melt flowability of the polyamide composition decrease, and when the melt flow rate becomes smaller than 50 g/10 m As a result, impact resistance decreases.

The base polymer constituting the modified low-crystalline ethylene/α-olefin copolymer is a copolymer of ethylene component units and a-olefin component units other than ethylene, and has ethylene component units as the main component. It is a low-crystalline ethylene/α-olefin copolymer. The content of the ethylene component unit is usually 95 to 50 mol%,
It is preferably in the range of 93 to 55 mol%, its crystallinity is usually in the range of 110% or less, preferably 35% or less, and its melt flow rate (M F R + 9
o・c ] is usually 0. '01 to 50g/10m1
n, preferably o, 'o, 2 to 20g/10ml
n range, and its glass transition temperature is usually -10°C
The temperature is preferably below -20'C. The α-olefin component units other than ethylene constituting the low-crystalline ethylene/α-olefin copolymer include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-
Dodecene, 1-tetradecene, 1-hexadecene, 1-
Examples include octadecene. □ The modified low-crystalline ethylene/α-olefin copolymer (B
) Examples of the unsaturated carboxylic acid or its derivative component unit of the graft monomer component include acrylic acid, methacrylic acid, a-ethyl acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, and methyl. Tetrahydrophthalic acid, endocis-bicyclo(2,2,L)hept-5-ene-2,6-
dicarboxylic acid (nadic acid), methyl-endocys-bicycloC2,2'l)hept-5-ene-2,3-
Dicarboxylic acid (methylnadic acid) includes all unsaturated dicarboxylic acids, acid halides of unsaturated dicarboxylic acids, derivatives of unsaturated dicarboxylic acids such as amides, imides, acid anhydrides, and esters. Examples of the salts include e-malenyl, 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.

A graft monomer selected from the unsaturated carboxylic acids or derivatives thereof is graft-copolymerized to the low-crystalline ethylene-σ-olefin copolymer to obtain the modified low-crystalline ethylene.
In order to produce the α-olefin copolymer, various conventionally known methods can be employed. For example, there is a method of graft copolymerization by adding a graft monomer that melts a low-crystalline ethylene/α-refin copolymer, or a method of dissolving it in a solvent and adding a graft monomer to carry out graft copolymerization. In both cases, a radical initiator may be used to efficiently graft copolymerize the graft monomer. The graft reaction is carried out at a temperature of 60 to 650°C (D temperature).The proportion of the 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. As the radical initiator, organic verokind, organic verester, azo compound, etc. can be used.

The ethylene/vinyl acetate copolymer (C) blended into the polyamide composition of the present invention is an ethylene/vinyl acetate random copolymer containing ethylene as a main component, and its crystallinity is 0 to 60. % and its 190°
Melt flow rate at C (M F R19o-c
), the melt flow sheet (M F R1', It is preferable that the q o -c )) is in the range of 0.05 to 50 g710 min.The ethylene/vinyl acetate copolymer may also contain a third copolymer component such as carbon monoxide. Regarding the physical properties of the ethylene/vinyl acetate copolymer, the content of ethylene component units is usually 70 to 9.
, 5 mol %2 to 99 mol %, preferably 75 to 99 mol %, the content of vinyl acetate component units is usually 2 to 30 mol %, preferably 2 to 25 mol %, and its melting point is Usually 105'Q or less, preferably 100
°C or less, and its density is usually between 0.92 and 0.92°C. ? 9 g/C7n3, preferably 0.93 to 0.9 g/C7n3. ．． 913 g/n'. The melt flow rate (M F
,R'? 9 o-c) is 0.01 g/10 m
When smaller than in, the impact resistance of the polyamide composition,
Melt fluidity decreases, 100g/IDm1
When the value is larger than n, the impact resistance decreases.

In the polyamide composition of the present invention, the modified ethylene/α-olefin, in, copolymer (Br and the ethylene, in,
When blending vinyl acetate copolymer (C) with polyamide, the melt temperature of both at 190°C (70-
(The ratio of MFR19oCJ\ [MFR19o-c]/[MFR79o-c] is usually adjusted to a range of 0.01 to 100, and further adjusted to a range of 0.02 to 50.

In the polyamide composition of the present invention, the polyamide (
The blending ratio of the modified low-crystalline ethylene/α-olefin copolymer (B) to 100 parts by weight of A) must be in the range of 1 to 100 parts by weight, and more preferably 2 to 100 parts by weight. , 180 parts by weight, particularly preferably in the range from 5 to 50 parts by weight. The blending ratio of the modified low crystalline ethylene/σ-olefin copolymer is 10.0.
If the amount is more than 1 part by weight, the rigidity and melt flowability of the polyamide composition will decrease, and if it is less than 1 part by weight, the impact resistance, stress resistance, crack resistance and water resistance of the polyamide composition will decrease. Also, 1. The blending ratio of ethylene, vinyl acetate copolymer (CJ) is in the range of 1 to 100 parts by weight based on 100 parts by weight of the polyamide (4). If the blending ratio of the ethylene/vinyl acetate copolymer is more than 100 parts by weight, it is preferably in the range of 2 to 80 parts by weight.1.Particularly preferably in the range of 5 to 50 parts by weight. The rigidity of the polyamide composition decreases, and when it becomes less than 1 part by weight, the impact resistance, stress crack resistance, and water resistance of the polyamide composition decrease. In the composition, the above-mentioned ethylene/alpha-olefin copolymer (B) is
The blending ratio of the vinyl acetate copolymer (C) is usually 5 to 20:00 parts by weight, preferably 10 to 1,500 parts by weight. Furthermore, in the polyamide composition of the present invention, the graft copolymerized unsaturated with respect to the total amount of the modified low-crystalline ethylene/a-olefin copolymer (B) and the ethylene/vinyl acetate copolymer (C). The proportion of carboxylic acid or its derivative component units is usually 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 an antioxidant, an ultraviolet m absorber, a photoprotector,
Phosphite stabilizer, peroxide decomposer, basic adjuvant, nucleating agent, plasticizer, lubricant, antistatic agent, flame retardant, pigment, dye (carbon blank, asbestos, lath fiber, carrion, It is also possible to incorporate fillers such as tasorek, silica, and silica alumina. 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 boria mid compositions of the present invention are prepared by melt mixing in a conventional manner. For example, two essential components may be premixed and then mixed with the remaining other components, or at the same time, the three essential components may be mixed with other remaining components that may be added as needed. 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 these, the composition obtained by melt-mixing polyamide (N component) to a premix obtained by preliminary melt-mixing of component (B) and (C) component when producing the composition has particularly excellent performance. ing.

Melt fluidity [melt flow rate (M
? , 255°C, 10'OOg load)] is normally 0.
It ranges from 1 to 5"0 (Ig/l Omin, preferably from 0.2 to 100 g/IDm1n.

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 crystallinity and the methane at 190° C.
9(1-c) was measured by the following method.

Crystallinity: Measured by X-ray diffraction at 26°C.

Melt flow rate (MF)! , 90°C): ASTM
D-+238-79 rr conditions (190°C, 21
6Clg).

Example 1 Maleic anhydride modified ethylene-propylene copolymer [ethylene content 80 mo/L/%, "R190'C1.8 g/
lo minute, density 0.87 g/Kushi 3, crystallinity 15%, maleic anhydride content 0.5 g/100 g base, M vi,
/yn7] and ethylene/vinyl acetate copolymer [vinyl acetate content 7 mol%, MF R, 190"05 g/1
0 nip, melting point 82°C1 crystallinity 36%, density 0.
9, dg fake 3] to the ratio shown in Table 1, 6
Premixing was carried out using a 0 mφ extruder (L/D 28.260°C). Next, this premix and nylon 6 [Toshishiku Co., Ltd.>'#-r Milan CM 1021XF, MFR5,
74 g/10 m1n, Q conditions] were mixed in the proportions shown in Table 1 to prepare a tri-blend pellet consisting of two types of pellets. Furthermore, it was supplied to a single screw extruder (L/D 28.50 mmφ) set at 260°C to prepare a melt blend (in the form of a pellet). The pellet was heated to 100'C.
After drying under vacuum for one day and night, injection molding was performed under the following conditions to prepare a substrate for measuring physical properties.

Cylinder temperature 26.0’Q Injection pressure 650kg/cM2 Injection time i, Qssc Mold temperature 80°C Subsequently, physical properties were evaluated by the following method.

MIFR measurement; MFR was measured under ASTM D-1238-79Q conditions.

Bending test; using a 1/8" thick test piece, ASTM I
) = 79'0-80, bending modulus FMCkg/cm
2), Bending yield strength F s (kVcpn2)
AU has been decided. By the way, the condition of the test piece was adjusted to 23"C.

The test was carried out for 6 days in a constant temperature and humidity room at 50% RH.

Falling weight impact strength: By dropping a weight of a certain shape from the height of the 9Q opening onto a test piece (diameter 50mmφ, thickness 1.2mm) horizontally at -60°C, and changing the weight of the weight, The falling weight impact strength was evaluated based on the weight (g) of the weight required to break 50% of a certain number of test pieces. In addition, □
The shape of the test piece was adjusted for 3 days at a constant temperature and humidity of 23° C. and 50% RH.

Izot impact strength: using a 1/8" thick test piece, A
-40°C notched Izot impact strength was measured using STM D 256. Conditioning of the test piece was at 23°C2.
The test was carried out for 3 days in a constant temperature and humidity room at 50% RH.

Water absorption test: According to ASTM D 570, a test piece (2 inch in diameter, 1/8 inch thick) was dried at 100'C for 24 hours, then subjected to a water absorption test in 50'C water for 48 hours, and water absorption was determined from the weight change rate of the test piece. The rate (%) was calculated.

The results are shown in Table 1.

Examples 2 to 9, Comparative Examples C to 5 Modified ethylene/α-olefin copolymers shown in Table 1 (
B) and ethylene/vinyl acetate copolymer CCI are shown in Table 1.
A blend was prepared in the same manner as in Example 1, except that the proportions shown were used, and the physical properties were determined.The results are shown in Table 1.
It was shown to. Table 1 shows the physical properties of the polyamide obtained when the modified ethylene/α-olefin copolymer (B) and the ethylene/vinyl acetate copolymer (C) were not blended (Comparative Example 1).

Claims (1)

[Scope of Claims] [1] Polyamide (phantom, modified low-crystalline, polyethylene,
A polyamide composition comprising an α-olefin copolymer CB) and an ethylene/vinyl acetate copolymer (C), wherein the composition of each component in the composition is (A) The modified low-crystalline ethylene/α-olefin copolymer (E) is present in an amount of 1 f, r to 100 parts by weight per 100 parts by weight of the modified low-crystalline ethylene/α-olefin copolymer (C ) is in the range of 1 to 100 parts by weight, ・ ・
(n) the modified low-crystalline ethylene/α-olewine;
The copolymer (B) is: 10.0 parts of a base low-crystalline ethylene/α-o-refin copolymer whose main component is ethylene, an unsaturated carboxylic acid or its The derivative component unit is graft copolymerized in the range of 0.01 to 10 parts by weight, the crystallinity is in the range of dQ% or less, and the melt flow rate (MFRl 9o -c] is 0.01 to 50g
, /,1. Thank you for the range of 190°C.
The flow rate (M F R19'oC) is o, ol
or 10. , Og/10 m'in.