JPH0463864A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition excellent in mechanical properties, heat resistance, chemical resistance and gloss and small in a change in dimension or properties upon absorption of water by mixing nylon 46 with a specified aliphatic polyamide and polybutylene terephthalate in a mixing ratio represented by specified formulas. CONSTITUTION:A resin composition comprising nylon 46 (A), an aliphatic polyamide (B) having a ratio of methylene groups to amide groups (CH2/NHCO) in the main chain of 6-11 and polybutylene terephthalate (C) and satisfying formulas I and II is obtained. In the above formulas, W(A), W(B) and W(C) represent the numbers of pts.wt. of the components, respectively. This resin composition excels in mechanical properties, heat resistance, chemical resistance and gloss, retains the excellent properties of nylon 46, is decreased markedly in a change in dimension or properties upon absorption of water, and can be extensively applied to the fields of automobiles, electrics, electronics, and machines by injection molding, extrusion molding, blow molding, expansion molding or the like.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a novel product that has excellent mechanical properties, heat resistance, chemical resistance, and gloss of molded products, and that changes in dimensions and physical properties due to water absorption are greatly suppressed. The present invention relates to a resin composition. More specifically, (A) nylon 46, (B) the ratio of methylene groups to amide groups in the polymer main chain (C) Iz/NHCO)
The present invention relates to a resin composition comprising an aliphatic polyamide having a polyamide of 6 to 11, and (C) polybutylene terephthalate.

The resin composition of the present invention has excellent mechanical properties, heat resistance, chemical resistance, and gloss of molded products, and changes in dimensions and physical properties due to water absorption are greatly suppressed, and can be used in injection molding, extrusion molding, blow molding, and foaming. Automobiles, electricity, etc. through molding etc.
It is applied to a wide range of fields such as electronics and machinery.

(Prior Art) Nylon 46, which is made of tetramethylene diamine, adipic acid, and functional derivatives thereof, is a well-known polyamide. For example, Japanese Patent Publications No. 60-8248 and Japanese Patent Publication No. 60-28843 disclose methods for manufacturing nylon 46 products. Nylon 46 is also known to have excellent properties as an engineering plastic, particularly excellent heat resistance. For example, its melting point is 295°C, which is not only higher than the 260°C of nylon 66, but also the 28°C of polyphenylene sulfide.
It exceeds even 5°C. High crystallinity and crystallization rate, heat distortion temperature (4.5Kg/c load) is 280°
It has a grade of C or higher, the highest value among engineering plastics. It also has excellent mechanical strength such as tensile strength and bending strength, sliding properties, and fatigue resistance.

However, nylon 46 has a higher concentration of amide groups than nylon 6 and nylon 66, so it has a problem of high water absorption. As a result, dimensional changes and physical property changes due to water absorption are large, and opportunities for application in a wide range of fields such as automobiles, electrical/electronic, and machinery have been limited.

As a method to improve this drawback, JP-A-62-15616
Publication No. 1 discloses a method of blending other polyamides having a melting point of 200'C or higher. JP-A-60-248
No. 775 discloses a resin composition of nylon 46 and nylon 12. However, in these cases, it was not possible to achieve a sufficient reduction in water absorption, and the heat resistance, which is the most important feature of nylon 46, was significantly reduced, making it less valuable as a molding material. Furthermore, when producing such resin compositions, the so-called balance effect often occurs, making compounding difficult.

Further, JP-A-62-185724 discloses blending a styrene polymer modified with a functional group. In this case, the water absorption rate is reduced, thereby suppressing dimensional changes, but the toughness, which is an excellent feature of nylon 46, is greatly reduced, and the mechanical properties are also significantly reduced. Also, in Japanese Patent Application Laid-Open No. 64-31866, nylon 46
A resin composition of a polyester and a polyolefin modified with a functional group is disclosed. In such a resin composition, the water absorption rate is lowered, thereby suppressing dimensional changes, but in this case as well, the heat resistance, which is the most important feature of nylon 46, is significantly lowered.

As mentioned above, many attempts have been made to reduce dimensional changes and changes in physical properties due to water absorption in nylon 46, but the effects are not sufficient, or the mechanical properties, heat resistance, or toughness, which are the characteristics of nylon 46, are significantly reduced. There were some problems.

Therefore, there has been a demand in a wide range of fields for a molding material that can greatly suppress changes in dimensions and physical properties due to water absorption without impairing the excellent mechanical properties, heat resistance, chemical resistance, etc. of nylon 46.

(Problems to be Solved by the Invention) In view of the above circumstances, the present invention aims to suppress the deterioration of dimensions and physical properties due to water absorption without impairing the excellent mechanical properties, heat resistance and chemical resistance of nylon 46. It is something to do. Another object of the present invention is to provide molded articles useful in a wide range of industrial fields such as automobiles, electrical/electronic, and machinery, by using resin compositions in which changes in dimensions and physical properties due to water absorption are reduced.

(Means for Solving the Problems) The present inventors have conducted intensive research to solve the above problems, and as a result, have arrived at the present invention. That is, (A) nylon 46, (B) an aliphatic polyamide in which the ratio of methylene groups to amide groups in the polymer main chain (CHz/NHCO) is 6 to 11, and (C) polybutylene ethylene phthalate. The gist is a resin composition that satisfies the following formulas [1] and (II).

However, -(A), -(B) and -(C) represent the weight blending parts of components (^) (B) and (C), respectively.

The resin composition of the present invention not only effectively suppresses the deterioration of dimensions and physical properties due to water absorption without impairing the excellent mechanical properties, heat resistance and chemical resistance of nylon 46, but also has the properties unique to nylon 46. It is surprising that the excellent toughness and gloss of the molded product are maintained.

Furthermore, the resin composition of the present invention provided a significantly higher heat resistance value than estimated from its constituent elements, and this effect was completely unexpected. In addition, when conventionally producing a resin composition consisting of nylon 46 and long-chain aliphatic polyamide, the so-called Halas effect occurs significantly and compounding is often difficult, but when producing the resin composition of the present invention, One of the remarkable features is that no such balance effect is observed, and productivity is greatly reduced.

Nylon 46, component (A), used in the present invention refers to polyamides and polyamide mixtures whose main constituent units are polyamides made of tetramethylene diamine, adipic acid, and functional derivatives thereof.
A part of the adipic acid component or tetramethylene diamine component may be replaced with another copolymer component.

The copolymerization component or mixed component is not particularly limited, and known amide group-forming components can be used.

Representative examples of copolymerized components include 6-aminocaproic acid, 1
Amino acids such as 1-aminoundecanoic acid, 12-aminododecanoic acid, para-aminomethylbenzoic acid, lactams such as ε-caprolactam and ω-lauryllactam, hexamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2.2.4 -/2,4.4-1-limethylhexamethylenediamine, 5-methylnonamethylenediamine, metaxylylenediamine, baraxylylenediamine, 1゜3-bis(aminomethyl)cyclohexane, 1,4bis(amino methyl) cyclohexane, ■-
Amino-3-aminomethyl-3.5.5-1-limethylcyclohexane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, amino Diamines such as ethylpiperazine, adipic acid, speric acid, azelaic acid, sebacic acid, dodecanoic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalate Examples include dicarboxylic acids such as acids, hexahydroterephthalic acid, hexahydroisophthalic acid, and diglycolic acid.

The method for producing nylon 46 used in the present invention is arbitrary. For example, Japanese Patent Publication No. 60-28843, Japanese Patent Publication No. 60-28843,
No. 0-8248, JP-A-58-83029,
and the method disclosed in JP-A No. 61-43631, in which a prepolymer with a small amount of cyclic end groups is first produced under specific conditions, and then solid phase polymerized in a steam atmosphere etc. to prepare high viscosity nylon 46. Particularly preferred are those obtained by a method of heating in a polar organic solvent such as 2-pyrrolidone or N-methylpyrrolidone.

There is no particular restriction on the degree of polymerization of nylon 46 used in the present invention, but the relative viscosity was determined using 96% sulfuric acid and the concentration was 1.
Nylon 46 having a g/d of 1.2 to 7.0, more preferably 1.5 to 5.5 when measured at 1.25°C is preferred. If the relative viscosity exceeds 7.0, not only the fluidity of the composition deteriorates, but also the variation in its mechanical and thermal properties becomes large, which is not preferable. If the relative viscosity is lower than 1.2, the disadvantage is that the mechanical strength of the composition is reduced.

The aliphatic polyamide as component (B) used in the present invention has a ratio of methylene groups to amide groups in the polymer main chain (CH2/N
HCO) is 6-11. Such polyamides include nylon 11, nylon 12, nylon 69, nylon 610, nylon 612, nylon 613, and nylon 1.
212 and the like. These aliphatic polyamides can also be copolymerized with other monomer components, if necessary. Among these aliphatic polyamides, nylon 12, nylon 610, nylon 612, and nylon 1212 are particularly preferably used.

The ratio of methylene groups to amide groups in the polymer main chain (CH, /
Polyamides having an NFICO of 5 or less are not preferred because they have no significant effect of reducing water absorption. Conversely, polyamides having a ratio of methylene groups to amide groups in the polymer main chain (CHz/NHCO) of 12 or more are undesirable because their heat resistance and mechanical properties are greatly reduced.

There is no particular restriction on the degree of polymerization of the aliphatic polyamide of component (B) used in the present invention, but the relative viscosity is 1 when measured using 96% sulfuric acid at a concentration of 1 g/dρ at 25°C.
．． A value in the range of 2 to 10.0 is preferred.

If the relative viscosity exceeds 10.0, the fluidity of the composition will not only deteriorate, but also the mechanical and thermal properties will vary widely, which is not preferable. If the relative viscosity is lower than 1.2, the disadvantage is that the mechanical strength of the composition is reduced.

The blending ratio of (A), (B) and (C) in the resin composition of the present invention needs to satisfy 2[I] and []II.

However, W(A), W(B) and W(C) represent the weight proportions of components (8), (B) and (C), respectively.

Composition ratio in formula (1) (W(B)+W(C))/
C (A) + W (B) + W (C) ] is (1,05
When the amount is less than 1, the effect of reducing the water absorption rate is not significant, and therefore, dimensional changes and changes in physical properties of the resin composition due to water absorption cannot be significantly suppressed.

On the other hand, if the ratio exceeds 0.5, the effect of reducing the water absorption rate is significant, but the heat resistance and mechanical properties are greatly reduced, which is not preferable. As shown in equation (1), the composition ratio (W(B)+W(C
) ) / (W(A)+W(B)+W(C)) is 0.
Only when the value is in the range of 0.05 to 0.5, the mechanical properties, heat resistance, chemical resistance, and gloss of the molded product are excellent, and
A resin composition can be obtained in which changes in dimensions and physical properties due to water absorption are largely suppressed.

Further, as shown in formula (II), the ratio [W (C) /W (B))] between -(B) and enemy (C) also needs to be within a certain range. That is, if the ratio is less than 0.2, the so-called halachic effect is significant during the production of the resin composition, which may cause difficulties in compounding. On the other hand, if the ratio exceeds 5.0, the mechanical properties of the resin composition will deteriorate significantly, which is not preferable.

It was previously pointed out that the resin composition of the present invention has a completely unexpected and remarkable effect of providing a heat resistance value that is significantly higher than that estimated from its constituent elements. This will be explained in more detail. For example, nylon 4670% by weight and nylon 1230! A resin composition containing 1% has a significant balancing effect during compounding and has extremely poor productivity. Further, the heat distortion temperature (4.5 kg/cm load) of this resin composition is 243°C, which is significantly lower than that of nylon 46, which is 285°C.

On the other hand, a resin composition consisting of 4670% by weight of nylon and 30% by weight of polybutylene terephthalate is extremely brittle.
The heat distortion temperature is also a low value of 230'C.

However, for example, nylon 4670% by weight and nylon 46
The three-component resin composition of the present invention comprising 70% by weight of polybutylene terephthalate and 10% by weight of polybutylene terephthalate has a heat distortion temperature of 280'C, and does not cause any harassing effect during compounding (it reduces productivity). Furthermore, there is no deterioration in toughness or mechanical properties, which is one of the major characteristics of nylon 46.

Such a remarkable effect is completely unexpected from its constituent elements.

Furthermore, pigments, heat stabilizers, antioxidants, weathering agents, flame retardants, plasticizers, mold release agents, reinforcing agents, etc. may be added to the resin composition of the present invention as long as they do not impair its moldability and physical properties. is possible. Reinforcements include glass fibers, metal fibers, potassium titanate whiskers, carbon fibers, fiber reinforcements such as aramid fibers, filler reinforcements such as talc, wollastonite, calcium carbonate, mica, glass flakes, and metal flakes. There is. Especially the diameter is 3~
Glass fibers of 20 μm are preferable because they further improve the strength, elastic modulus, and heat resistance of the resin composition.

Furthermore, it is also possible to add other polymers to the resin composition of the present invention, if necessary. Main specific examples of these polymers are listed below.

Polybutadiene, butadiene-styrene copolymer, acrylic rubber, ethylene-propylene copolymer, EPDM,
Rubber-like polymers such as natural rubber, chlorinated butyl rubber and chlorinated polyethylene, elastomers such as styrene-butadiene block copolymer, styrene-phtadiene-styrene radial teleblock copolymer, polyamides such as nylon 6 and nylon 66, Polypropylene, butadiene acrylonitrile copolymer, polyvinyl chloride, PET,
Thermoplastic resins include polyacetal, polyvinylidene fluoride, polysulfone, PPS, polyethersulfone, phenoxy resin, PPO, PMMA, and polyetherketone.

The method for producing the resin composition of the present invention or the method for obtaining various molded articles from the resin composition of the present invention is arbitrary. For example, the components of the resin composition of the present invention may be mixed using a Banbury mixer, a tumbler mixer, or other methods, and the mixture may be directly molded by methods such as injection molding, extrusion molding, and blow molding to form various molded products. I can do it.

In addition, each component is mixed using a Banbury mixer, tumbler mixer, or other method, and this is melt-kneaded and cut using an extruder to form a pellet, which is then processed by injection molding, extrusion molding, blow molding, or other methods. It can also be molded into various molded products.

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited thereto. The measurement methods and raw materials used in Examples and Comparative Examples are as follows.

Standard V unilateral ASTM 0790 Izot "Voice ASTM D256.3.2mm thickness, heat with notch"
[Modified ASTM D678, load 4.5 Kg/cffl rabbit 1Q] Processed for 24 hours under the conditions of 65°C x 95% RH.

The average dimensional change in each direction of a test piece with a length of 501 mm, a width of 50 mm, and a thickness of 3 mm was measured.

Measured using ASTM D523 at an incident angle of 60 degrees.1 The test piece used to evaluate dimensional changes was immersed in toluene at room temperature for 165 hours to examine changes in appearance and weight.

Nylon 46: F5000 nylon 61, made by Unitika ■
0: Made by Toshi ■, CM2O01 Nylon 12: Ube Industries ■
Co., Ltd., 3014U nylon 612: made by Tisselhüls ■, 014PBT: made by Mitsubishi Kasei ■, 5010 Examples 1 to 5, Comparative Examples 1 to 3 After mixing each raw material in a tumbler at the compounding ratio shown in Table 1, the mixture was heated at 90°C. Vacuum drying was performed for 16 hours. Then, using a twin screw extruder (manufactured by Ikegai Iron Works, PCM45),
The pellets were melt-kneaded at a temperature of 0°C and cut to obtain pellets of the resin composition. This pellet is molded into an injection molding machine (Nippon Steel).
A test piece was obtained by molding at a temperature of 300° C. The test piece was subjected to various physical property measurements.

Among these, in Examples 1 to 5, the resin compositions were melt-kneaded without any problems and pellets were easily obtained, but in Comparative Example 2, the Halas effect occurred during melt-kneading of the resin composition, making it extremely difficult to form pellets. there were.

Table 1 shows the results of physical property measurements. As specifically shown in Table 1, the resin composition of the example retained the performance of nylon 46 alone in terms of mechanical properties such as bending strength and isot impact strength, and initial performance such as heat distortion temperature and chemical resistance. Water absorption rate is decreasing. The deterioration of physical properties after water absorption treatment is also significantly less than that of nylon 46 alone. On the other hand, in the comparative examples, the occurrence of a ballast effect, a decrease in mechanical strength, and a decrease in heat resistance and strength were observed.

Examples 6 to 9 Resin composition pellets having the compositions listed in Table 2 were obtained in exactly the same manner as in Examples 1 to 5. With any of the resin compositions, pellets were easily obtained without causing any harassing effect. A test piece was molded using this pellet.

Table 2 lists the results of performance evaluation using the obtained test pieces. As specifically shown in Table 2, the resin compositions of the examples retained most of the properties of nylon 46 in terms of mechanical properties, heat resistance, chemical resistance, and gloss of molded products, but the disadvantages of water absorption caused the resin compositions to Changes in properties and physical properties are significantly suppressed.

changes are largely suppressed. In addition, the occurrence of a ballast effect during melt-kneading is also suppressed. Furthermore, the resin composition of the present invention has a heat resistance that is significantly higher than that expected from its constituent elements.

Patent applicant: Unitika Co., Ltd. table (Effect of the invention)

Claims (1)

[Claims] (1) (A) Nylon 46 and (B) the ratio of methylene groups to amide groups in the polymer main chain (CH_2/NHCO) is 6
~11, and (C) polybutylene terephthalate, and has the following formulas [I] and [II]
A resin composition that satisfies the following. 0.05≦W(B)+W(C)/W(A)+W(B)+
W(C)≦0.5 [I]0.2≦W(C)/W(B)
≦5.0 [II] However, W(A), W(B) and W(C
) represents the proportion by weight of components (A), (B) and (C), respectively.