JPH0288672A - Polymer composition and production thereof - Google Patents

Abstract

PURPOSE:To obtain a composition having excellent balance of mechanical characteristics, heat resistance, impact resistance and moldability, etc., by kneading a polyamide resin with an unsaturated carboxylic acid modified rubber using a twin-screw extruder under specific conditions. CONSTITUTION:The aimed polymer composition is obtained by kneading (A) 30-90wt.% polyamide resin with (B) 10-70wt.% of (B1) rubber and (B2) unsaturated carboxylic acid modified rubber (preferably ethylene-butene rubber in the both rubber components) wherein ratio of mol number of terminal amine of the component A to mol number of carboxylic acid group of component B2 is 10-1000 using a twin-screw extruder (e.g., shown in the figure) having a hopper 1, the first kneading zones 4 and 4', the second kneading zone 5, vacuum bent part 3 and dice outlet 2 and being >=25 in ratio of length to diameter (L/D) under specific conditions and consisting of a continuous matrix phase formed by the component A and domain phase uniformly dispersed by the component B and having 0.1-5mum average diameter.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a polymer composition whose main components are polyamide resin and rubber, and which particularly has an excellent balance of mechanical properties, heat resistance, impact resistance, moldability, etc. The present invention relates to a polymer composition mainly composed of polyamide resin and rubber, and a method for producing the same.

[Conventional technology]

Polyamide resin is lightweight and has excellent mechanical properties, heat resistance, abrasion resistance, chemical resistance, etc.

Among these, nylon 6 and nylon 66, which have particularly excellent strength and heat resistance, are often used.

However, polyamide resin molded products have poor mechanical strength.
Although it has excellent heat resistance and long-term durability, it has the problem of insufficient impact resistance.

Rubber generally possesses the properties that are lacking as described above.

JP-A No. 50-6693 discloses a method consisting of (A) a polyamide resin, (B) a cross-linked elastomer having epoxy and oxy functional groups, and (C) a fine particle filler; is the weight ratio (A): (
B) Rubber reinforced polyamides with a ratio of -100 = 6 to 100 near 0 are disclosed. In this rubber-reinforced polyamide, the polyamide forms a continuous phase and the elastomer forms a dispersed phase, and at the interface between the two, the amide group of the polyamide resin and the epoxy and oxy functional groups of the elastomer are chemically bonded. is combined with Since this rubber-reinforced polyamide is composed of a polyamide resin and a modified elastomer, the compatibility between the two is too high and the physical properties are averaged, resulting in an unbalanced mechanical strength, heat resistance, impact resistance, moldability, etc.

Furthermore, JP-A-55-165952 discloses (A) 50 to 99 parts by weight of a polyamide resin, and (B) an alicyclic carboxylic acid having a cis-type double bond in the ring in a polyolefin or a polyolefin elastomer, and a functional derivative thereof. At least one compound selected from the group consisting of o,
A polyamide composition comprising 50 to 1 part by weight of a modified polyolefin or a modified olefin elastomer added thereto in an amount of 0 to 10 mol % is disclosed. Furthermore, an example in which an unmodified polyolefin is added to this polyamide composition is also disclosed.

[Problem to be solved by the invention]

However, in the polyamide composition disclosed in JP-A-55-165952, the polyamide resin and modified polyolefin are too compatible, and mechanical strength, heat resistance, impact resistance, moldability, etc. are not well balanced. I don't have it.

Therefore, the object of the present invention is to make use of the properties of polyamide resin, especially heat deformation resistance, while having the impact resistance of rubber.
An object of the present invention is to provide a polymer composition with an excellent balance between heat resistance and impact resistance.

Another object of the present invention is to provide a method for manufacturing such polymer compositions.

[Means to solve the problem]

In view of the above problems, as a result of intensive research, the present inventor added rubber and unsaturated carboxylic acid-modified rubber to polyamide resin, and created a specific structure in which the rubber was uniformly dispersed in the matrix phase of polyamide resin as a domain phase with a specific diameter. A polymer composition that maintains the heat deformation resistance of polyamide resin and has good impact resistance of rubber by forming a morphology, and has a well-balanced mechanical strength, heat resistance, impact resistance, moldability, etc. The present invention was conceived based on the discovery that the following can be obtained.

That is, the polymer composition of the present invention contains a polyamide resin, a rubber, and an unsaturated carboxylic acid-modified rubber, in which the polyamide resin forms a continuous matrix phase and the rubber is uniformly dispersed in a 0.1 to 5 μm thick layer. It is characterized by forming a domain phase with an average diameter of .

The method of the present invention for producing such a polymer composition also includes:
Using a twin-screw extruder having a hopper, a vacuum vent, and a die outlet in order, and having a length-to-inner diameter ratio (L/D) of 25 or more, polyamide resin, rubber, and unsaturated carboxylic acid-modified extruder are extracted from the hopper. L/DI/4 to 178 before reaching L/D15 on the downstream side of the hopper.
The components are strongly kneaded in at least one first kneading zone consisting of four or more consecutive kneading disks, and
5 or more, before reaching the vacuum vent part, the ingredients are strongly kneaded again in at least one second kneading zone constituted by four or more consecutive kneading disks.

The present invention will be explained in detail below.

The polyamide resin used in the present invention includes hexamethylene diamine, decamethylene diamine, dodecamethylene diamine, 2,2.4- or 244-) I
J Methylhexamethylene diamine, 1,3- or 1.
4-bis(aminomethyl)cyclohexane, bis(p-
aliphatic, cycloaliphatic or aromatic diamines such as m- or p-xylylene diamine (aminocyclohexylmethane), m- or p-xylylene diamine; Polyamide resins made from aliphatic, alicyclic or aromatic dicarboxylic acids, polyamide resins made from aminocarboxylic acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, ε - Polyamide resins produced from lactams such as caprolactam and ω-dodecalactam, copolyamide resins consisting of these components, or mixtures of these polyamide resins. Specifically, nylon 6, nylon 66, nylon 610, nylon 9, nylon 676G, nylon 66/610, nylon 6/
11, nylon 6/12, nylon 12, nylon 47
6 etc. is mentioned. Among these, nylon 6 and nylon 66 are preferred.

Although the molecular weight is not particularly limited, the relative viscosity ηr (J
A polyamide resin having an ISK68 (measured in 10.98% sulfuric acid) of 1.0 or more is used, and among them, a polyamide resin of 2.0 or more is preferable because it has excellent mechanical strength.

Furthermore, the rubbers used in the present invention include natural comb, ethylene-propylene rubber (BPR), and ethylene-propylene rubber (BPR).
Propylene-diene rubber (BPDM), ethylene-
Butene rubber (BBR), butadiene rubber (BR), imprene rubber (IR), styrene-butadiene rubber (SB
R), nitrile-butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), hydrogenated styrene-butadiene block copolymer rubber (SBBS)
, polyisobutylene rubber, acrylic rubber, etc.

Among these rubbers, ethylene-butene rubber (B[1l
l), ethylene-propylene rubber (BPR) and hydrogenated styrene-butadiene block copolymer rubber (SBB
S) is preferred. By using these rubbers as the rubber component, particularly excellent impact resistance can be obtained.

The modified rubber used in the present invention is a rubber modified with an unsaturated carboxylic acid or its anhydride. Examples of unsaturated carboxylic acids or their anhydrides include monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid, fumaric acid,
Examples include dicarboxylic acids such as itaconic acid, maleic anhydride, dicarboxylic anhydrides such as itaconic anhydride, and dicarboxylic acids and their anhydrides are particularly preferred.

Further, as the rubber modified with an unsaturated carboxylic acid or its anhydride, the above-mentioned rubbers can be similarly used, and in particular, ethylene-butene rubber (BBR), ethylene-propylene rubber (BPR), and hydrogenated styrene-butadiene block copolymer. (SBBS) is preferred.

Particularly excellent impact resistance can be obtained by using these rubbers as the rubber component of the modified rubber.

The content of unsaturated carboxylic acid or its anhydride in the modified rubber is preferably 0.01 to 15% by weight.

If the amount of modification is less than 0.01% by weight, the addition of the modified rubber will not have a sufficient effect on improving the compatibility between the polyamide resin and the rubber, and if it exceeds 15% by weight, the compatibility with the rubber will decrease.

The modified rubber can be produced by either a solution method or a melt-kneading method. In the case of the melt-kneading method, the rubber, unsaturated carboxylic acid for modification (or acid anhydride), and catalyst are put into an extruder, twin-screw kneader, etc., and are heated to a temperature of 150 to 250 °C and kneaded while melting. .

In the case of a solution method, the starting material is dissolved in an organic solvent such as xylene, and the solution is stirred at a temperature of 80 to 140°C. In either case, ordinary radical polymerization catalysts can be used as catalysts, such as benzoyl peroxide, lauroyl peroxide, di-tert-butyl peroxide, acetyl peroxide, tertiary-butylperoquine benzoic acid, peroxide dicumyl, peroxybenzoic acid, peroxyacetic acid,
Peroxides such as tertiary-butylperoxypivalate and 2,5-dimethyl-2,5-ditertiary-butylperoxyhexine, and diazo compounds such as azobisisobutyronitrile are preferred. The amount of the catalyst added is about 1 to 100 parts by weight per 100 parts by weight of the unsaturated carboxylic acid for modification or its anhydride.

In the polymer composition of the present invention, the blending amounts of the polyamide resin and the rubber component are not particularly limited. In order to have good properties such as strength and impact resistance, the content of polyamide resin must be 30 to 90% by weight based on the total of polyamide resin and rubber components (rubber + modified rubber), and the content of rubber + modified rubber must be 30 to 90% by weight. is preferably 10 to 70% by weight. Particularly preferred ranges are 50 to 70% by weight of polyamide resin and 30 to 50% by weight of rubber + modified rubber.

The amount of modified rubber is correlated to the amount of terminal amine in the polyamide resin to control the domain size of the rubber. That is, it is preferable to adjust the content of the modified rubber so that the ratio of the number of moles of terminal amine to the number of moles of carboxylic acid groups in the modified rubber is 10 to 1000. If the amine/carboxylic acid molar ratio is less than 10, compatibilization will proceed too much and the domain diameter of the rubber will become too small, resulting in a decrease in heat resistance. If the amine/carboxylic acid molar ratio exceeds 1000, the compatibilizing effect of the modified rubber will be insufficient, and the resulting composition will have low mechanical strength. A more preferable molar ratio is 20~
It is 200. The content of modified rubber is generally 0.1 to 20% by weight, particularly preferably 0.5 to 10% by weight, within the range that satisfies the above requirements.

In the polymer composition of the present invention, the polyamide resin forms a continuous matrix phase and the rubber has an average diameter of 0.1 to 5.
It is characterized by forming a μm domain phase. If the polyamide resin does not form a continuous matrix phase,
Alternatively, if the average diameter of the rubber domains is less than 0.1 μm, the heat deformation resistance of the composition is extremely low. Furthermore, if the average diameter of the rubber domains exceeds 5 μm, the mechanical properties of the composition such as tensile strength, flexural modulus, and impact strength will be significantly insufficient.

The polymer composition of the present invention may also contain other additives for its modification, such as inorganic fillers, heat stabilizers, antioxidants, light stabilizers, flame retardants, plasticizers, antistatic agents, release agents, etc. A molding agent, a foaming agent, a nucleating agent, etc. can be added.

Next, a method for producing the polymer composition of the present invention will be explained.

First, a twin-screw extruder meeting the following requirements is used.

(a) It has a hopper, a vacuum vent part, and a die outlet in this order, and the ratio of length to inner diameter (L/D) is 25 or more, and (a) It has a polyamide resin and At least one set of first kneading zones (L/Di/4 to 1) for intensively kneading the rubber component
(C) at least one set of second kneading zones for intensively kneading the resin and rubber components again before reaching the vacuum vent section; (The kneading disk is composed of four or more consecutive kneading disks.)

Regarding (a), the hopper is for charging polyamide resin, rubber, and modified rubber, and the vacuum vent is for removing low molecular weight components generated during kneading of the polyamide resin and rubber components. The outlet is for extruding the kneaded composition into a strand.

Regarding (b), the first kneading zone is for particularly intensively kneading the polyamide resin and the rubber component, and a plurality of the first kneading zones are provided as necessary. 8. The first kneading saw is preferably composed of four or more consecutive kneading disks, particularly 4 to 16, having an L/DI of 4 to 178. The multiple pairs of kneading disks are each fixed to two screw shafts and rotated by the rotation of the screws.

Each kneading disk has a cam-like shape, and as it rotates, the distance between the multiple pairs of kneading disks increases or decreases. As a result, the polyamide resin and rubber component passing between them are strongly kneaded.

Regarding (C), the second kneading zone performs strong kneading with the polyamide resin and the rubber component again, and its structure itself is not essentially different from the first kneading zone.

A twin-screw extruder having the above characteristics specifically has a structure as shown in FIG. 1, for example. A preferred structure of this twin-screw extruder is as follows.

(i) The length/diameter (L/D) ratio of the twin-screw extruder is 25 or more, (11) a hopper 1 for charging the polyamide resin and the rubber component, and (jji) for extruding the obtained polymer composition. (iv) a vacuum vent section 3 provided between the hopper 1 and the die 2; (v) at least a vacuum vent section 3 provided before reaching the downstream L/D 15 of the hopper 1; (vi) at least one set of second kneading zones 5 provided before reaching the vacuum vent section 3; has.

In addition, the crosstalk conditions are as follows: (vii) The temperature of the polyamide resin and rubber during kneading by this twin-screw extruder is 250 to 300°C, and (vm) The temperature of the resin and rubber at the die exit is 250 to 300°C.
The temperature shall be 300°C.

If the L/D ratio of the twin-screw extruder is less than 25, sufficient kneading cannot be achieved. A preferred L/D ratio is 25-35.

The hopper 1, the vacuum vent section 3, and the die 2 may each have a known structure.

The distance between hopper 1 and vacuum vent part 3 is L/D5~20
It is preferable to set it to . If the distance L/D between the two is less than 15, the kneading will be insufficient and the effect of venting will be small;
If it exceeds 0, vent-up is likely to occur.

Both the first kneading zone 4.4' and the second kneading zone 5 have L/D of about 1 to 4.
/D is about 1/4 to 1/8 kneading disks 4
It is preferable to use a continuous combination of two or more sheets.

Here, the structure of each kneading zone is as shown in FIG. 2, for example. A plurality of kneading disks 12, 12'... provided in the middle of two screws 10, 11.
- A kneading zone N is formed, and there are screw zones s and s' before and after it.

In the kneading zone N, the kneading disks 12, 12'... are each fixed to two screw shafts and form a pair. FIG. 3 shows a cross section of a pair of kneading discs 12, 12'. Each kneading disc 12.12' has a cam-shaped outer circumferential surface and each has a projection 13.13' and a circumferential part 14.14'. The protrusion 13.13' and the circumference 14.1 in multiple pairs
4' are opposed to each other, the kneading disk 12
．． 12' is a spline groove 15. 15' to a screw shaft (not shown). Therefore, in multiple pairs, the distance between the kneading disks 12, 12' increases or decreases significantly as the screw shaft rotates.

As shown in Figure 2, the kneading disc 12.12
Since a plurality of '... are provided in succession, the polyamide resin and rubber components passing through the multiple pairs of gaps are subjected to much stronger kneading than by the screw. Furthermore, the second
In the configuration shown in the figure, the transition portion (seal ring) T is formed on the downstream side of the kneading zone N, so that the material to be kneaded does not easily move beyond the kneading zone.

The kneading zones having the structure as described above are used as the second kneading zone at least one set, preferably two sets.
It is necessary to provide at least one set, and at least one set or more must be provided as the second kneading zone.

If the 121 ding zone 4.4' is absent or does not have a sufficient length, the polyamide resin and rubber component will be insufficiently kneaded and plasticized insufficiently.

Further, if the length of the second kneading zone 5 is shorter than L/DI due to a shortage of kneading disks, problems such as the particle size of the rubber domains not being uniform occur.

In addition, if there are two or more sets of 121 ding zones 4.4' for boat fishing, the tip of the 121 ding zone 4.4' is located downstream of the hopper 1 at
~20 positions, and the total length is about L/D2~8. The tip of the second kneading zone 5 is located at L/D15 to L/D20 on the downstream side of the hopper 1, and the total length is about L/D1 to L/D4.

Also, the temperature of the polyamide resin and rubber during kneading is 250~
If the temperature is lower than 300°C, the desired morphology cannot be obtained. However, if the temperature of the polyamide resin and rubber is too high, the resin will deteriorate and the desired performance will not be obtained.

A polyamide resin and a rubber component are charged into the hopper 1 of the twin-screw extruder, and the polyamide resin and rubber component are kneaded while rotating two screws at a speed of 100 to 300 rpm. The composition obtained by kneading is obtained as a strand from the die outlet 2, and can be easily pelletized using a strand cutter.

The polymer composition of the present invention produced using the twin-screw extruder described above can be molded into a desired shape by a conventional injection molding method.

[For production]

As mentioned above, the polymer composition of the present invention maintains high heat deformation resistance by changing the morphology of the composition so that the polyamide resin forms a continuous matrix phase, so that the polyamide resin forms the resin skeleton. .

It is also important that the domain diameter of the rubber is 0.1 μm or more and that it is not made compatibilized with the polyamide resin more than necessary in order not to impair the heat resistance of the polyamide resin skeleton. On the other hand, if the domain diameter of the rubber exceeds 5 μm, the mechanical properties will deteriorate due to reasons such as cracks occurring on the domain surface in response to external stress.

Furthermore, in the method of the present invention, by using a twin screw extruder having a first kneading zone and a second kneading zone for kneading the polyamide resin and the rubber component, stable and strong kneading can be performed. . This improves the uniform dispersion of the resin and rubber, which have poor compatibility, such as polyamide resin and rubber, and improves the mechanical strength and heat resistance of the resulting composition.

[Example] The present invention will be explained in further detail by the following examples.

Examples 1 to 18 Polyamide resin, rubber, and modified rubber were triblended using a high-speed mixer in the proportions shown in Table 1, and the mixture was charged into the hopper of a twin-screw extruder shown in FIG.

The structure of the twin screw extruder used was as follows.

Outer diameter of screw 45mm L/D ratio 28 Vacuum vent position Upstream side of die L/D5
．． 5 Number of first kneading zones 2 Position Downstream side of hopper L/D2~3.
5 And/D5~6.5 position Size of kneading disk L/D=1/4 Number of kneading disks 6 Number of second kneading zones 1 Position Upstream side of die L/D? Size of kneading disk L/D=1/4 Number of kneading disks 4 In addition, the resin temperature at each part in the twin screw extruder was as follows.

Examples 1 to 12.15.16...270℃Example 1
3.14...250°C Example 17.18.
...290° C. Composition pellets were produced by rotating the screw at a speed of 20 Orpm using this twin-screw extruder.

After drying the obtained composition pellets in a drying oven, test pieces were prepared by injection molding, and the following tests were conducted.

(1) MFR=275 according to JIS K 7210
Measured at ℃ under a load of 2160 g.

(2) Heat deformation temperature - When the temperature is raised at a constant rate (2°C/min), llQmm X 4mm X 12.7 + TllT
1 test piece (simple beam) was subjected to a constant load (4.6 kg/cn
! ) is bent by a specified amount (0.25 mm), and the temperature is measured according to JIS K 7207.

(3) Tensile strength = JIS K 711 at 23°C
Measured by 3.

(4) Flexural modulus = JIS K 720 at 23°C
Measured by 3.

(5) Izot impact strength = Measured according to JIS K 7110 at 23°C and -40°C.

The results are also shown in Table 1.

(1) The contents of polyamide, rubber and modified rubber are expressed in weight percent based on the resin and rubber components.

(2) Amiran CM3001111Korsh made on the east side
ak-Zamyationa's method (Dorendyo method) (Ch
em, Abs, 40.4665. '46. Same as above 4
2.6152. The terminal amino group measured in '48) was 0.
．． 034 m equivalent/g.

(3) Unitika A103AlO30BRTKor
shak-Za 1ona method (same method as (2))
The terminal amine group determined by the method was 0.042 equivalent/g.

(4) Unitika Nylon 46K manufactured by Unitika ■.

The terminal amino group measured by the rshak-Zamyationa method (same method as (2)) is 0.026 equivalent/
It was g.

(5) Tafmar A4085 manufactured by Mitsui Petrochemical ■ (6) Tafmar PO180 manufactured by Mitsui Petrochemical ■ (7) Clayton G1652 manufactured by Shell (8) Vistanex M manufactured by Esso Chemical ■
ML-80 (9) Maleic Anhydride Comparative Examples 1 to 5 Compositions were produced in the same manner as in Example 1, except that the materials and blending ratios shown in Table 2 were used, and the same tests were conducted.

The results are shown in Table 2.

Note 1 (1), (2), (5), (6), (9) Same as Table 1 In the composition of the invention, the rubber domains within the range of 0.1 to 5 μm are uniformly dispersed in the nylon phase, so it has good impact resistance and heat resistance. The compositions of Comparative Examples having polypropylene domains and those containing no modified rubber have poor heat deformation resistance and impact resistance.

[Effects of the Invention] As detailed above, the polymer composition of the present invention not only contains an unsaturated carboxylic acid-modified rubber that helps make the polyamide resin and rubber compatible, but also has an average diameter within a specific range. Since the rubber has a morphology that is uniformly dispersed in the polyamide resin matrix phase, it has excellent heat deformation resistance and impact resistance, and has an excellent balance of tensile strength, moldability, etc. Furthermore, it has the advantage of reduced costs due to the relatively large amount of polyolefin it contains.

Such a composition of the present invention is particularly suitable for use as parts for industrial machinery, automobiles, electrical equipment, etc., and building materials by injection molding or extrusion molding.

[Brief explanation of drawings]

FIG. 1 is a partially cross-sectional schematic side view showing an example of a twin-screw extruder for producing a fiber-reinforced polymer composition by the method of the present invention, and FIG. 2 is a twin-screw extruder used in the method of the present invention. FIG. 3 is a partially enlarged view showing a kneading zone, and FIG. 3 is a sectional view showing an example of a pair of kneading disks. 1... Hopper 2... Die 3... Vent 4.4'... First kneading zone 5... Second kneading zone 10 11... Screw 12, 12'... Knee ding disc 13, 1
3'...Protruding parts 14, 14'...Circumferential parts 15, 15'...Spline groove N...Kneading zone T...Seal rings s, s'...Part of screw

Claims (5)

[Claims] (1) Contains a polyamide resin, rubber, and unsaturated carboxylic acid-modified rubber, the polyamide resin forms a continuous matrix phase, and the rubber is uniformly dispersed.
A polymer composition characterized in that it forms a domain phase with an average diameter of μm. (2) The polymer composition according to claim 1, wherein the ratio of the number of moles of the terminal amine in the polyamide resin to the number of moles of the carboxylic acid group in the unsaturated carboxylic acid-modified rubber is 1.
A polymer composition characterized in that it has a molecular weight of 0 to 1000. (3) The polymer composition according to claim 1 or 2, wherein the polyamide resin is 30 to 90% by weight, and the total of the rubber and the unsaturated carboxylic acid-modified rubber is 10 to 7% by weight.
A polymer composition characterized in that it contains 0% by weight. (4) The polymer composition according to any one of claims 1 to 3, wherein the rubber components of the rubber and the unsaturated carboxylic acid-modified rubber are ethylene-butene rubber, ethylene-propylene rubber, or hydrogenated styrene-butadiene-rubber. A polymer composition characterized in that it is a block copolymer rubber. (5) A method for producing a polymer composition containing a polyamide resin, rubber, and unsaturated carboxylic acid-modified rubber, comprising, in order, a hopper, a vacuum vent, and a die outlet;
Using a twin-screw extruder with a length-to-inner diameter ratio (L/D) of 25 or more, the polyamide resin, the rubber, and the unsaturated carboxylic acid-modified rubber are charged from the hopper, and the L on the downstream side from the hopper is charged. Before reaching /D15, L/D1/
In at least one set of first kneading zones consisting of four or more continuous kneading disks of 4 to 1/8, the ingredients are strongly kneaded, and further downstream from the hopper, at an L/D of 15 or more, the vacuum vent section Before reaching L
/D A method characterized by strongly kneading the ingredients again in at least one set of second kneading zones comprising four or more consecutive kneading disks of 1/4 to 1/8.