JP2008285564A - Polyolefin-polyamide resin composition and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyolefin-polyamide resin composition which is capable of operating for a long period of time, is excellent in productivity and has a stable quality, and a method for producing the same. <P>SOLUTION: This composition comprising a polyolefin matrix and fine polyamide fibers dispersed in the matrix is formed by putting a polyolefin, a polyamide and an ionomer simultaneously into a biaxial extruder 1 without using an organic peroxide compound which is a cause of gel formation in the production process, kneading and extruding, drawing an extruded material 4 from a spinneret nozzle 3 and taking up or sheeting while imposing a draft. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin composition comprising a polyolefin and a polyamide, and relates to a polyolefin-polyamide resin composition that can be used as a reinforcing material for rubber and resin, and a method for producing the same.

  In order to improve mechanical strength such as elastic modulus and strength of rubber and resin, carbon fiber or glass fiber or organic fiber with high elastic modulus such as aromatic polyamide fiber, cellulose fiber, etc. are blended. It was common. However, due to the dispersibility of the fibers and the bondability between the fiber and the matrix, sufficient performance does not necessarily occur. Due to the problems of workability, the productivity of the molded product is poor and the appearance is poor. Use is limited to specific fields.

  JP-A-7-238189, JP-A-9-59431, and Journal of Japanese Society of Rheology vol.25 No.5, pages 275 to 282 (1997) describe in-situ fiber fiber using a polyolefin and a rubbery polymer as a matrix. A composition in which fine nylon fibers are formed in a matrix using the technique of in situ fiber formation is disclosed. It is possible to obtain a short fiber reinforced composite having excellent mechanical properties by blending this composition with rubber or resin. Japanese Patent Application Laid-Open No. 11-106570 discloses a composition in which fine nylon fibers are formed in a polyolefin matrix using the same technique in two components of a polyolefin-polyamide resin.

  These series of inventions are composed of the following three steps. First, the first step in which the polymer constituting the matrix and the silane coupling agent are reacted via an organic peroxide through a closed kneader to modify the silane, and then the matrix polymer and the polyamide resin modified in the first step. The second step in which the polyamide resin is finely dispersed in the matrix polymer by kneading and reacting with a twin-screw kneader, then extruding the kneaded / reacted material, taking it out while drafting, and fine nylon fibers in the matrix It consists of the 3rd process made to form. In this series of steps, the organic peroxide used in the first step is not necessarily completely consumed but remains in a trace amount, and the residual organic peroxide is not contained in the polymer in the second and subsequent steps. This is a production method that causes gelation, makes continuous operation impossible for a long time, and extremely low productivity, and has the disadvantages that it becomes a major factor in cost increase and that it is difficult to produce a product of stable quality.

JP 7-238189 A JP-A-9-59431 JP-A-11-106570 Journal of Japanese Society of Rheology vol.25 No.5 pages 275-282 (1997)

  An object of the present invention is to provide a polyolefin-polyamide resin composition that solves the above-described problems and is excellent in productivity and economy and stable in quality.

  In order to achieve the above object, the present invention does not use organic peroxidation which is a cause of gel generation, but directly inputs (a) polyolefin, (b) polyamide, and (c) ionomer into a twin-screw extruder, By kneading and extruding, taking up or rolling while drafting, (a) the polyamide matrix is dispersed in (b) a fiber having an average diameter of 1000 nm or less and finished into a pellet. A polyolefin-polyamide resin composition and a method for producing the same.

  The manufacturing apparatus can be operated continuously for a long time, which not only greatly reduces the cost, but also provides a stable product in terms of quality.

  Hereinafter, the structural components in the polyolefin-polyamide resin composition of the present invention and the production method thereof will be specifically described. The component (a) is a polyolefin, preferably in the form of pellets having a melting point of 80 to 250 ° C. Examples of such suitable examples include homopolymers and copolymers of olefins having 2 to 8 carbon atoms, and olefins having 2 to 8 carbon atoms and aromatic vinyl compounds such as styrene, chlorostyrene, and α-methylstyrene. Copolymer, copolymer of olefin having 2 to 8 carbon atoms and vinyl acetate, copolymer of olefin having 2 to 8 carbon atoms and acrylic acid or ester thereof, and olefin having 2 to 8 carbon atoms and vinylsilane compound These copolymers are preferably used.

  Specific examples include high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, ethylene / propylene block copolymer, ethylene / propylene random copolymer, ethylene / vinyl alcohol copolymer, ethylene / acrylic acid copolymer. Polymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / propyl acrylate copolymer, ethylene / butyl acrylate copolymer, ethylene / ethyl 2-ethylhexyl acrylate copolymer, Examples include ethylene / hydroxyethyl acrylate copolymer, ethylene / vinyltrimethoxysilane, ethylene / vinyltriethoxysilane, ethylene / vinylsilane copolymer, ethylene / styrene copolymer, and propylene / styrene copolymer.

  Among the polyolefins of component (a), particularly preferred are high density polyethylene <HDPE>, low density polyethylene (LDPE), linear low density polyethylene <LLDPE>, polypropylene (PP), and ethylene / propylene block copolymer. , Ethylene / propylene random copolymer, ethylene / vinyl acetate copolymer <EVA>, and ethylene / ethyl acrylate copolymer (EEA), with a melt flow index (MI) of 0.2 to 50 g / 10. Those that can be formed into pellets within a range of minutes are most preferred. These may use only 1 type and may combine 2 or more types.

  The component (b) is a thermoplastic polyamide having an amide group in the main chain (hereinafter abbreviated as polyamide), and has a melting point in the range of 135 to 350 ° C., and more than the melting point of the polyolefin as the component (a). It is high, and in particular, a material having a melting point in the range of 160 to 265 ° C is preferable. As this (b) component, the polyamide which gives a tough fiber by extrusion and extending | stretching is mentioned as a preferable thing.

  Specific examples of polyamide include nylon 6, nylon 66, nylon 6-nylon 66 copolymer, nylon 610, nylon 612 nylon 46, nylon 11 nylon 12, nylon MXD6, polycondensate of xylylenediamine and adipic acid, Polycondensates of rangeamine and pimelic acid, polycondensates of xylylenediamine and speric acid, polycondensates of xylylenediamine and azelaic acid, polycondensates of xylylenediamine and terephthalic acid, octamethylenediamine And terephthalic acid polycondensates, trimethylhexamethylenediamine and terephthalic acid polycondensates, decamethylenediamine and terephthalic acid polycondensates, undecamethylenediamine and terephthalic acid polycondensates, dodecamethylenediamine A polycondensate of terephthalic acid with tetramethyl Polycondensates of rangeamine and isophthalic acid, polycondensates of octamethylenediamine and isophthalic acid, polycondensates of trimethylhexamethylenediamine and isophthalic acid, polycondensates of decamethylenediamine and isophthalic acid, undecamethylenediamine And a polycondensate of isophthalic acid and a polycondensate of dodecamethylenediamine and isophthalic acid.

  Among these polyamides, particularly preferred specific examples include nylon 6 <PA6>, nylon 66 <PA66>, nylon 12 <PA12>, nylon 6-nylon 66 copolymer, and the like. One or more of these may be used. These polyamides preferably have a molecular weight in the range of 10,000 to 200,000. (B) component is 2-100 weight part with respect to 100 weight part of (a) component, Preferably it is 5-75 weight part, Most preferably, it is 10-50 weight part. When the component (b) is less than 2 parts by weight, fine particles are formed and the reinforcing property cannot be obtained. On the other hand, when the amount is more than 100 parts by weight, it becomes difficult to form fine fibers, ribbon-like ones are easily formed, and the strength and elongation are greatly reduced. The melting point of component (b) must be at least 20 ° C., preferably 40 ° C., more preferably 50 ° C. higher than the melting point of component (a). If the difference between the melting point of the component (b) and the melting point of the component (a) is 20 ° C. or less, fiber formation of the component (b) is not achieved, and good fibers cannot be obtained. Further, when the composition is molded, the fiber of component (b) melts, and the shape of the fiber cannot be maintained, so that only a molded product with low reinforcement can be obtained.

  The component (c) is an ionic polymer having a small amount of ionic groups introduced into the polymer chain, and is generally called an ionomer. Typical ionomers include host hydrophobic polymers such as polyethylene, polystyrene, tetrafluoroethylene, etc., ionic polymers with a small amount of carboxyl groups and sulfone groups introduced as side chains, with metal ions or ammonium ions. It is a Japanese one. Examples of the counter ion include alkali metal ions and alkaline earth metal ions, transition metal ions, organic ammonium ions, transition metal-organic aluminum complex ions, anions, and the like.

Specific examples of ionomers are:
As an ethylene ionomer,
Ethylene-methacrylic acid copolymer (Chemical formula 1)
_{- (CH 2 -CH 2) m} - (CH 2 -CH (CH 3) (COO - M +)) n -
Ethylene-acrylic acid copolymer (Chemical formula 2)
_{- (CH 2 -CH 2) m} - (CH 2 -CH 2 (COO - M +)) n -

As a styrene ionomer,
Styrene-methacrylic acid copolymer (Chemical formula 3)
_{- (CH 2 -CH 2 (C} 6 H 6)) m - (CH 2 -CH 2 (CH 3) (COO - M +)) n -
Styrene-styrene sulfonic acid copolymer (chemical formula 4)
_{- (CH 2 -CH 2 (C} 6 H 6)) m - (CH 2 -CH 2 (C 6 H 5 SO 3 - M +)) n -
Styrene-styrene carboxylic acid copolymer
_{- (CH 2 -CH 2 (C} 6 H 6)) m - (CH 2 -CH 2 (COO - M +)) n -

As a perfluorocarbon ionomer,
(Chemical formula 6)
_{- <CF 2 -CF 2> m-} <CF <-O-CF 2 -CF 2- SO 3 - M +> -CF 2) n -

As a telechelic ionomer,
(Chemical formula 7)
_{-OOC- <CH 2 -CH = CH-} CH 2> n-COO-M +

As polyurethane ionomer,
(Chemical Formula 8)
_{-R 1 OOCNHR 2 NHCONH-R 1} -N <CH 2 CH 2 SO 3 -M +> CONH-R 2 -
Etc.

Here, M ⁺ in the above chemical formula is a counter ion for neutralizing the ionic polymer, such as Na, Li, Ca, Al, Mg, Zn, Mn, Co, Ni, Cu, Fe, etc. Ions.
Among these ionomers, particularly preferred specific examples include metal salts of Na ⁺ and Zn ⁺² of ethylene-methacrylic acid copolymer and ethylene / acrylic acid copolymer, and one or two of these are included. May be used.

  The proportion of component (c) is 1 to 50 parts by weight, preferably 2 to 30 parts by weight, per 100 parts by weight of component (a) polyolefin. When the amount of the component (c) is less than 1 part by weight, good fine fibers are not formed, and the strength and elongation of the composition are low. When the amount is more than 50 parts by weight, the polyamide forms fine particles. The elastic modulus is low.

  Next, the manufacturing method of the polyolefin-polyamide resin composition of this invention is demonstrated. Manufactured from the following steps.

  First, the kneading / reaction process will be described. Three types of (a) component polyolefin, (b) component polyamide and (c) component ionomer are supplied from the supply port of the kneader and kneaded at a mixed temperature higher by 20 ° C. than the melting point of the polyamide. As the kneader, a continuous kneader such as a closed kneader such as a Banbury mixer or a kneader, a single-screw kneader, or a twin-screw kneader is used. A twin-screw kneader that is excellent in kneading ability and that can continuously perform the fiberizing step of the next step is most preferable both technically and economically. By kneading these three components, the amide group of the polyamide of component (b) reacts with the carboxylate of the metal salt of the ethylene-methacrylic acid copolymer of component (c), and the components (b) and (c) A graft copolymer is formed, this graft copolymer acts as a compatibilizing agent, and (b) component polyamide is finely and uniformly dispersed in (a) component polyolefin by the principle of microphase separation. .

  Next, the polyamide fiberizing step will be described with reference to FIG. The kneaded product (polyolefin, polyamide, ionomer kneaded product) obtained in the kneading / reaction process is supplied to the twin-screw extruder 1 and extruded from the spinning nozzle 3. The extrusion temperature is preferably 20 ° C. or higher than the melting point of the component (b). Even if extrusion is performed at a temperature lower than the melting point of the component (b), the component (b) does not become fine fibers. The extrudate 4 is pulled through the roll 5 while applying tension while cooling right under the nozzle 3. The take-up speed, that is, the draft ratio (take-up speed / speed at the nozzle outlet) is preferably in the range of 1.5 to 100, more preferably in the range of 2 to 50, and particularly preferably 3 to 30. By this take-up operation, the polyamide particles in the extrudate are deformed and converted into fibers. The extrudate strand taken up may be wound into a string or may be supplied to a pelletizer 7 as shown in FIG. 1 and cut into a pellet.

  Although the above steps have been described separately from the kneading / reaction step and the fiberizing step, a spinning nozzle having a plurality of nozzles is installed at the tip of the uniaxial kneader or the biaxial kneader, and as a continuous process It is possible to implement. By doing so, labor saving and energy saving can be achieved, and a product with stable quality can be obtained.

  In addition to this, the polyolefin-polyamide resin composition of the present invention includes carbon black, white carbon, activated calcium carbonate, ultrafine magnesium silicate, high styrene resin, phenol resin, lignin, modified melamine resin, coumarone indene resin, calcium carbonate, base Fillers such as basic magnesium carbonate, clay, zinc white, diatomaceous earth, recycled rubber, powder rubber, ebonite powder, amines / aldehydes, amines / ketones, phenols, imidazoles, sulfur-containing antioxidants, phosphorus-containing oxidations Stabilizers such as inhibitors and various pigments may be included.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to the range of these Examples. In the examples and comparative examples, the characteristics and physical properties of the production method of the polyolefin-polyamide resin composition were measured as follows.

(Discharge rate)
Every 2 hours from the start of operation, pellets are collected for 1 minute at the hopper chute of a pelletizer that cuts the extrudate strand and weighed. This operation was performed three times and the average was calculated as the discharge amount.

(Continuous operation time)
The time from when the components (a), (b), and (c) are added to the twin-screw extruder (start of operation) until the extrudate strand is frequently cut and pellets cannot be collected continuously. It was set as driving time.

(Strand uniformity)
A portion of the extrudate strand was sampled every 2 hours from the start of operation and measured with a micrometer.

(Generation of eye grease)
The size of the eye grease generated in the spinneret every 0.5 hours from the start of the operation time was visually observed.

(Yield)
The percentage of (polyolefin-polyamide resin composition product) with respect to (from (a) component + (b) component + (c) component total charge) from the start to the end of continuous operation was calculated as a yield.

(Discoloration in the extruder)
After completion of the continuous operation, the twin screw extruder was disassembled, and the burned state of the barrel and the screw was visually confirmed.

(Fiber shape)
The pellets of the resin composition were dissolved in hot xylene, the fibers were taken out and washed, and then observed with a scanning electron microscope. ○ when it is observed as a fine fiber, △ when a fine fiber and fine particles are mixed, or a mixture of other fibers and ribbons, or only fine particles In the case of, evaluation was made with x.

(Average fiber diameter)
The fiber diameter was measured from the scanning electron micrograph, and the average was obtained as the average diameter. In addition, the particle diameter was calculated as the fiber diameter in the case of the particle form, and the film width was calculated in the case of the film form (ribbon form).

(Tensile modulus, tensile strength, elongation)
The pellets of the polyolefin-polyamide resin composition are wound around a 3-inch roll set at 150 ° C., rolled out at a roll interval of 2 mm, and a sheet in which nylon fibers are sufficiently oriented in the roll-out direction is created. A sheet having a smooth surface was formed by a press at 120 ° C. to a thickness of 2 mm, and measured at a temperature of 23 ° C. and a tensile speed of 200 mm / min according to JIS K6760.

[Example 1] 100 parts by weight of low density polyethylene (manufactured by Maruzen Ube, F120N, melting point 110 ° C) as component (a), nylon 6 (1024B, melting point 215 to 225 ° C, manufactured by Ube Industries) as component (b) 50 parts by weight and 15 parts by weight of ionomer (manufactured by Mitsui DuPont, Himiran 1706, melting point 88 ° C.) as component (c) were simultaneously charged into a twin screw extruder and kneaded and reacted at 240 ° C. Extruded into a strand shape from a die (nozzle diameter 2 mm, nozzle number 50) installed at the tip, drawn with a draft 10 with a take-up roll while being air-cooled, stretched 1.5 times between 5 inch rolls, and then a pelletizer And pelletized.
The operating conditions were fixed so that the extrusion amount at the start of operation was 50 kg / hr, the current value and the resin pressure were continuously recorded, and the change with time was observed. During the operation for 48 hours, there was no change in the current value, the resin pressure, and the extrusion amount, and the operation was stable. During the operation, a slight amount of grease was observed around the nozzle, but it was of a level that did not hinder the operation at all, but the grease was removed every 2 hours just in case. The operation was completed in 48 hours, and the extruder was immediately disassembled, and the occurrence of burns in the screw part and the die part was observed. Table 1 shows the results of these operating conditions.

  The shape of the obtained pellet was 0.7 mm in diameter and 3 mm in length. The obtained pellet was eluted with hot xylene from polyethylene and unreacted ionomer. The insoluble part was suspended in xylene. When the insoluble part was observed with a scanning electron microscope, it was a fine fiber having an average diameter of about 300 nm. Various characteristic values are shown in Table 1 together with the form of these nylons. Moreover, since the image observed with the scanning electron microscope was image | photographed, the electron micrograph is shown in FIG.

  [Examples 2 to 6] Low density polyethylene, nylon 6, and ionomer were blended as shown in Table 1, and the same treatment as in Example 1 was performed. The results are shown in Table 1. As is apparent from Table 1, also in Examples 2 to 6, substantially the same results as in Example 1 could be obtained. In Example 6, fine fibers and fine particles were mixed in the nylon shape, but the same results as in Example 1 could be obtained with respect to various characteristics.

  [Comparative Examples 1-2] Low density polyethylene, nylon 6, and ionomer were blended as shown in Table 1, and the same treatment as in Example 1 was performed. The results are shown in Table 1.

  [Examples 7 and 8] The same operation as in Example 1 was performed except that the draft ratio was changed. Even when the draft ratio was increased, no strand breakage occurred, and good spinnability was exhibited.

It is a schematic block diagram of the polyolefin-polyamide resin composition manufacturing apparatus which concerns on this Embodiment. 4 is an electron micrograph of the solvent extraction residue (insoluble part medium) of pellets obtained in Example 1. FIG.

Explanation of symbols

1 Twin Screw Extruder 3 Spinning Nozzle 4 Extrudate 5 Roll 7 Pelletizer

Claims (3)

A composition comprising (a) 100 parts by weight of polyolefin, (b) 2 to 100 parts by weight of polyamide, and (c) 1 to 50 parts by weight of an ionomer, wherein the graph copolymer of component (b) and component (c) A polyolefin-polyamide resin composition having a structure in which component (b) is dispersed as fine fibers in component (a). 2. The polyolefin-polyamide resin composition according to claim 1, wherein the polyamide dispersed in a fibrous form has an average diameter of 1000 nm or less and an aspect ratio of 2 or more and 1000 or less. (A) Polyolefin, (b) Polyamide, and (c) Ionomer are melted, kneaded, extruded, drawn, stretched or rolled while hanging on a draft, and (a) Polyamide has an average diameter of 1000 nm in (b) Polyolefin. The method for producing a polyolefin-polyamide resin composition according to claim 1, wherein the polyolefin-polyamide resin composition is dispersed in the following fiber form and finished in a pellet form.

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