JPH036942B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyamide resin composition having excellent rigidity, impact resistance, and salt water resistance. Polyamide resins are expected to be in great demand as engineering plastics due to their excellent physical properties. However, low-temperature impact resistance is not sufficient, and improvements are desired. As a method for improving impact resistance such as Izotz impact strength, methods such as those disclosed in Japanese Patent Publication No. 12546/1980, Japanese Patent Publication No. 44108/1982, Japanese Patent Application Laid-open No. 9661/1983, and Japanese Patent Application Laid-open No. 9662/1982 are available. Prior art literature proposes a method of blending an ethylene/α-olefin copolymer grafted with an α,β-unsaturated carboxylic acid into a polyamide resin. In all of these proposed compositions, when the impact resistance such as Izotz impact strength is improved, the rigidity is greatly reduced and the falling weight impact strength at low temperatures is also insufficient, resulting in molded products having low-temperature impact resistance. It has the disadvantage of becoming inferior in sex. In addition, 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 that require such performance, especially 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 these prior art compositions proposed in this paper can improve water resistance such as water absorption and salt water decomposition resistance, they do not have the effect of improving impact resistance such as Izot impact strength, especially low-temperature impact resistance. It has the disadvantage of being inferior in terms of The present inventors investigated a method for developing a polyamide resin composition with excellent performance, and found that a specific amount of modified ethylene and α
- an olefin copolymer and a specified amount of ethylene;
A composition containing a neutralized α,β-unsaturated monocarboxylic acid copolymer has high impact resistance such as isot impact strength and low-temperature falling weight impact strength, and stress resistance without significantly decreasing rigidity. The present invention has been achieved based on the discovery that crack resistance is improved and water resistance such as water absorption and salt water decomposition resistance under salt water conditions are significantly improved. That is, the present invention consists of three components: polyamide (A), modified ethylene/α-olefin copolymer (B), and neutralized product of ethylene-α,β-unsaturated monocarboxylic acid copolymer (C). is a composition in which the weight ratio of each component is (A):(B):(C)=100:1 to 30:2 to 40, and (B) is ethylene. Graft polymerization of 0.05 to 10 parts by weight of a graft monomer selected from unsaturated dicarboxylic acids or derivatives thereof to 100 parts by weight of an ethylene/α-olefin copolymer consisting of 40 to 93 mol% and 60 to 7 mol% of α-olefin. It is a modified ethylene/α-olefin copolymer with an intrinsic viscosity [η] in the range of 0.5 to 4 dl/g when measured in a decalin solvent at 135°C, and (C) is a copolymer of ethylene and α, β. - At least 5% of the carboxyl groups of the copolymer consisting of 25 to 1 mol% of unsaturated monocarboxylic acid are neutralized with metal ions or ammonium ions, and the melt flow rate [MFR (190°C)] is 0.1 to 1%.
The composition is characterized in that it is in the range of 1000g/10min. The polyamides (A) used in the present invention are well known in the state of the art. These are of sufficient molecular weight to produce molded articles. Polyamides can be prepared by condensing equimolar amounts of saturated organic dicarboxylic acids containing from 4 to 12 carbon atoms with organic diamines containing from 2 to 13 carbon atoms. Here, if desired, diamines can be used such that there is an excess of amine end groups over carboxyl end groups in the polyamide. Conversely, dicarboxylic acids can also be used in such a way that there is an excess of acid groups. Also well, Oster, acid chloride,
These polyamides can also be made from the amine and acid-forming derivatives and amine-forming derivatives, such as amine salts and the like. Typical dicarboxylic acids used to make polyamides include adipic acid, pimelic acid, superric acid, sebacic 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), polyhexamethylene sebaamide (6.10 nylon) and polyhexamethylene dodecanoamide (6.12 nylon), polybis(4-aminocyclohexyl)methandodecanamide, or a polyamide prepared by ring opening of lactamic acid, i.e. polycaprolactam (6
nylon), 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 abovementioned polyamides, for example polymers made from adipic acid and isophthalic acid and hexamethylene diamine. It is. Also included are 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 (nylon 6.6) or polyhexamethylene adipamide (nylon 6.6) and polycaprolactam (nylon 6). Modified ethylene α blended into the composition of the present invention
-Olefin copolymer (B) is a low-crystalline or amorphous ethylene with specific properties. This is a modified ethylene/α-olefin copolymer obtained by graft copolymerizing an α-olefin copolymer with a specific amount of a graft monomer selected from unsaturated dicarboxylic acids or derivatives thereof. The ethylene/α-olefin copolymer subjected to graft modification has an ethylene content of
It needs to be in the range of 40 to 93 mol%, and more preferably in the range of 60 to 93 mol%. Even if the ethylene content of the ethylene/α-olefin copolymer becomes higher than 93 mol% or lower than 40 mol%, the ethylene/α-olefin copolymer becomes highly crystalline,
Even if the graft modified product of the copolymer is blended with polyamide in combination with (C) described below, the effect of improving the impact resistance and water resistance of the composition cannot be said to be sufficient. In addition, the intrinsic viscosity [η] of the ethylene/α-olefin copolymer measured in decalin solvent at 135°C was
It is preferably in the range of 0.5 to 4 dl/g, particularly preferably 0.8 to 3 dl/g. [η] of the ethylene/α-olefin copolymer is 0.5 dl/
Even if it is smaller than 4 dl/g or larger than 4 dl/g, the difference in melt viscosity between the graft-modified ethylene/α-olefin copolymer obtained from the copolymer and the polyamide becomes too large, so the graft-modified A sufficient dispersion effect of the substance into the polyamide cannot be obtained, and even if it is combined with (C) described later, the effect of improving impact resistance is not exhibited. Further, the density of the ethylene/α-olefin copolymer is usually 0.92 g/cm ³ or less, more preferably in the range of 0.86 to 0.90 g/cm ³ . Furthermore, the ethylene/α-olefin copolymer is low crystalline or amorphous, and its crystallinity is usually in the range of 0 to 50%, preferably 0.
It ranges from 30% to 30%. The α-olefin component units constituting the ethylene/α-olefin copolymer include propylene, 1-butene, 1-hexene, 4-methyl-1
-Pentene, 1-decene, 1-hexadecene, 1
- Icosene, etc., and it is one kind or a mixture of two or more kinds thereof. The ethylene/α-olefin copolymer is usually a copolymer of an ethylene component and an α-olefin, but in some cases it may contain a trace amount, for example, 0.5 mol% or less, of a diene component. can not use. Modified ethylene α blended into the composition of the present invention
-Olefin copolymer (B) is the ethylene/α-
This is a modified ethylene/α-olefin copolymer obtained by graft copolymerizing an unsaturated dicarboxylic acid or its graft monomer to an olefin copolymer. The grafting ratio of the graft monomer is based on 100 parts by weight of the ethylene/α-olefin copolymer.
It is necessary to range from 0.05 to 10 parts by weight, and more preferably from 0.08 to 5 parts by weight. When the grafting ratio of the graft monomer is less than 0.05 parts by weight, the Izot impact strength and low temperature impact strength decrease, and the
If the amount exceeds the weight part, impact strength, rigidity, and water resistance will decrease. In addition, the modified ethylene α
−135 in decalin solvent of olefin copolymer (B)
The intrinsic viscosity [η] measured at °C is 0.5 to 4 dl/
It is necessary to be in the range of 0.8 to 3 dl/g, and more preferably in the range of 0.8 to 3 dl/g. When the intrinsic viscosity [η] of the modified ethylene/α-olefin copolymer is less than 0.5 dl/g, the impact resistance such as Izot impact strength and low-temperature impact strength and water resistance of molded articles made from the composition deteriorate. When it becomes larger than 4 dl/g, the impact resistance starts to decrease. Furthermore, the modified ethylene α
- The degree of crystallinity of the olefin copolymer measured by X-ray diffraction is usually in the range of 0 to 50%, preferably 0 to 30%, and its density is usually in the range of 0.86 to 0.95 g/cm ³ , preferably 0.87 and 0.92 g/cm ³ . Examples of unsaturated dicarboxylic acids or derivatives thereof as graft monomer components constituting the modified ethylene/α-olefin copolymer include maleic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, and isocrotonic acid. , unsaturated dicarboxylic acids such as nadic acid (endocys-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid), methyl nadic acid, or derivatives thereof, such as acid halides, amides, imides, acid anhydrides, Examples include esters, and 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 anhydride and nadic anhydride are particularly preferred. To produce the ethylene/α-olefin copolymer by graft copolymerizing the graft monomer selected from the unsaturated dicarboxylic acids or derivatives thereof to the ethylene/α-olefin copolymer, various conventionally known methods can be used. Can be adopted. For example, there is a method of melting an ethylene/α-olefin copolymer and adding a graft monomer to carry out graft copolymerization, or a method of dissolving the ethylene/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 graft copolymerization in the presence of a radical initiator. The grafting reaction is usually carried out at a temperature of 60 to 350°C.
The proportion of the radical initiator used is usually in the range of 0.01 to 20 parts by weight per 100 parts by weight of the ethylene/α-olefin copolymer. As radical initiators, organic peroxides, organic peresters such as benzoyl peroxydi, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-
Butyl peroxide, 2,5-dimethyl-2,5
-di(peroxybenzoate)hexyne-3,
1,4-bis(tert-butylperoxoisopropyl)benzene, lauroyl peroxide, tert
-Butyl peracetate, 2,5-dimethyl-
2,5-di(tert-butylperoxy)hexane-3, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl perbenzoate, tert-butyl phenyl acetate,
tert-butyl perisobutyrate, tert-butyl per-sec-octoate, tert-butyl perpivalate, cumyl perpivalate and tert-butyl perdiethyl acetate, other azo compounds such as azobisisobutyronitrile, dimethyl azo There is isobutyrate. Among these, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-
Dialkyl peroxides such as butylperoxy)hexane-3,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 1,4-bis(tert-butylperoxyisopropyl)benzene are preferred. Ethylene α,β- constituting the composition of the present invention
The neutralized product (C) of the unsaturated monocarboxylic acid copolymer contains at least 5%, preferably at least 5% of the carboxyl groups of the random copolymer consisting of ethylene and 25 to 1 mol% of α,β-unsaturated monocarboxylic acid. 10% or more is neutralized with metal ions or ammonium ions. Further, the ethylene copolymer may be further copolymerized with a vinyl monomer other than the α,β-unsaturated monocarboxylic acid. The ethylene content of the ethylene/α,β-unsaturated monocarboxylic acid copolymer is usually 70 to 99 mol%.
is within the range of Its melt flow rate [MFR
(190℃)] must be in the range of 0.1 to 1000g/10min, and furthermore, 0.3 to 200g/10min.
Preferably, the time is in the range of 10 min. If the melt flow rate of the neutralized product (C) of the ethylene/α,β-unsaturated monocarboxylic acid copolymer is greater than 1000 g/10 min, the impact strength and water resistance of the molded product obtained from the composition will decrease. 0.1
If it is smaller than g/10 min, the impact strength of the molded article obtained from the composition will decrease. Specific examples of the α,β-unsaturated monocarboxylic acid constituting the ethylene/α,β-unsaturated monocarboxylic acid copolymer include acrylic acid and methacrylic acid. Examples of vinyl monomers other than α,β-unsaturated monocarboxylic acids include vinyl acetate and (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, and isobutyl (meth)acrylate. Further, as metal ions, metal ions having a valence of 1 to 3,
In particular, it is a metal ion having a valence of 1 to 3 in groups A and A in the periodic table of elements, specifically, Na ⁺ , K ⁺ , Li ⁺ , Cs ⁺ ,
Ag ⁺ , Hg ⁺ , Cu ⁺ , Be ⁺⁺ , Mg ⁺⁺ , Ca ⁺⁺ , Sr ⁺⁺ , Ba ⁺⁺ ,
Cu ⁺⁺ , Cd ⁺⁺ , Hg ⁺⁺ , Sn ⁺⁺ , Pb ⁺⁺ , Fe ⁺⁺ , Co ⁺⁺ , Ni ⁺⁺ ,
Examples include Zn ⁺⁺ , Al ⁺⁺⁺ , Sc ⁺⁺⁺ , Fe ⁺⁺⁺ , Y ⁺⁺⁺ and the like.
These metal ions may be a mixed component of two or more types, or may be a mixed component with ammonium ions. In the composition of the present invention, the polyamide (A)
The blending ratio of the modified ethylene/α-olefin copolymer (B) to 100 parts by weight must be in the range of 1 to 30 parts by weight, and further 2 to 30 parts by weight.
Preferably it is in the range of 20 parts by weight. If the blending ratio of the modified ethylene/α-olefin copolymer (B) exceeds 30 parts by weight, the molded product obtained from the composition will have poor rigidity, and if it is less than 1 part by weight, the durability of the molded product will deteriorate. Impact resistance becomes inferior. Further, the blending ratio of the neutralized product (C) of the ethylene/α,β-unsaturated monocarboxylic acid copolymer to 100 parts by weight of the polyamide (A) must be in the range of 2 to 40 parts by weight. Yes, even 4 or more
Preferably it is in the range of 30 parts by weight. When the blending ratio of the neutralized product (C) of the ethylene/α,β-unsaturated monocarboxylic acid copolymer is more than 40 parts by weight,
A molded article obtained from the composition will have poor impact resistance and water resistance, and if the amount is less than 2 parts by weight, the molded article will have poor water resistance. 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. It is also possible to incorporate fillers such as nucleating agents, plasticizers, lubricants, antistatic agents, flame retardants, pigments, carbon black, asbestos, glass fibers, kaolin, talc, 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 compositions of the present invention are prepared by melt mixing in a variety of ways. For example, two optional essential components may be premixed and then mixed with the remaining other components, or three essential components may be mixed at the same time. 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, and water resistance. Among them, in particular, the composition obtained by melt-mixing the polyamide (A) component into a premix prepared by melt-mixing the (B) component and (C) component is particularly suitable for producing the composition. Excellent performance. The melt fluidity [melt flow rate [MFR, 235°C, 2.16 kg 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 composition of the present invention can be molded into various shapes by various conventionally known melt molding methods. Examples include injection molding, extrusion molding, compression molding, and foam molding.
Used for a wide range of applications including electrical parts. Next, the present invention will be specifically explained using examples. Example 1 Nylon 6 [manufactured by Toray Industries, Inc., Amilan CM-
1017XF, MFR 41 g/10 min, Q conditions], maleic anhydride modified ethylene/1-butene copolymer [ethylene content 92 mol%, MFR ₁₉₀ °C 11 g/10 min, density
0.90 g/cm ³ , crystallinity 17%, maleic anhydride unit content 0.5 parts by weight per 100 parts by weight of base ethylene/1-butene copolymer] and ethylene/methacrylic acid, isobutyl obtained by high pressure method. Table 1 shows the Zn neutralized product (degree of neutralization 70%, MFR 1.0) of methacrylate tertiary random copolymer (methacrylic acid unit content 3.7 mol% isobutyl methacrylate unit content 2.3 mol%, MFR ₁₉₀ °C 35 g/10 minutes) A dry blend consisting of three types of pellets was prepared by mixing the pellets in the proportions shown below. 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 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,
Flexural modulus FM according to ASTM D-790-80
(Kg/cm ² ) and bending yield strength FS (Kg/cm ² ). The test piece was conditioned at 23℃ and 50%
This was done for 3 days in a constant temperature and humidity room with RH. Izot impact strength: Using a 1/8" thick test piece, the unnotched Izot impact strength was measured at -20°C according to ASTM D-256. The test piece was conditioned in a constant temperature and humidity room at 23°C and 50% RH. 3
Natsuta Nikko. In addition, using the dry product of the melt blend pellets mentioned above, the outer diameter was
A tube with a diameter of 4.76 mm and a wall thickness of 0.6 mm was molded. After leaving the molded tube for one day, take a designated test piece,
Conditioning was carried out for one day in a constant temperature and humidity room at 23°C and 50% RH. Zinc chloride resistance; JASO
23℃ according to method M317−73 (former number 7318)
was immersed in a 50% zinc chloride aqueous solution, and the time required for cracks to occur was investigated. Examples 2 to 6, Comparative Examples 1 to 7 Neutralized products of the modified ethylene/α-olefin copolymers and ethylene/α,β-unsaturated carboxylic acid random copolymers shown in Table 1 are shown in Table 1. A blend was prepared in the same manner as in Example 1 except that the proportions were used, and the physical properties were measured. The results are shown in Table 1.

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Claims (1)

[Scope of Claims] 1. From three components: polyamide (A), modified ethylene/α-olefin copolymer (B), and neutralized product of ethylene/α,β-unsaturated monocarboxylic acid copolymer (C) The composition is a composition in which the weight ratio of each component is (A):(B):(C)=100:1 to 30:2 to 40, and (B) is Grafting 0.05 to 10 parts by weight of a graft monomer selected from unsaturated dicarboxylic acids or derivatives thereof to 100 parts by weight of an ethylene/α-olefin copolymer consisting of 40 to 93 mol% ethylene and 60 to 7 mol% α-olefin. It is a modified ethylene/α-olefin copolymer whose intrinsic viscosity [η] measured at 135°C in a decalin solvent is in the range of 0.5 to 4 dl/g, and (C) is a copolymer of ethylene and α-olefin. , at least 5% of the carboxyl groups of the copolymer consisting of 1 to 25 mol% of β-unsaturated monocarboxylic acid are neutralized with metal ions or ammonium ions, and the melt flow rate [MFR (190°C)] is 0.1 or more
A composition characterized in that it is in the range of 1000g/10min. 2. The composition according to claim 1, wherein (B) is a modified ethylene/α-olefin copolymer having a crystallinity of 0 to 50%. 3 (B) α-olefin has 3 to 20 carbon atoms
- The composition according to claim 1, which is an olefin. 4. The composition according to claim 1, wherein the unsaturated dicarboxylic acid or its derivative (B) is a compound selected from maleic acid, nadic acid and derivatives thereof. 5. The composition according to claim 1, wherein the α,β-unsaturated monocarboxylic acid (C) is acrylic acid or methacrylic acid. 6. The composition according to claim 1, wherein the carboxyl group of (C) is neutralized with an alkali metal ion, an alkaline earth metal ion, zinc or ammonium ion. 7. The composition according to claim 1, wherein the degree of neutralization of the carboxyl group in (C) is 10% or more.