JPH06106528A - Production of polyamide resin composition - Google Patents

Abstract

PURPOSE:To obtain a novel method for producing a resin composition of polyamide and polypropylene enhanced in mechanical characteristics and dimensional stability in a humid atmosphere and improved in heat resistance with a smaller energy at a low cost. CONSTITUTION:In a single-screw or multi-screw extruder provided with an extruding opening part at the top end thereof, two or more supply opening parts are provided so as to have different distances from the top end. To the supply opening part far apart from the top end, (1) a polypropylene and (2) at least one kind of unsatd. compound selected out of a group of unsatd. carboxylic acid, derivatives of unsatd. carboxylic acid, and unsatd. epoxy compound are supplied by a fixed amount. To the supply opening part near the top end, a polyamide is supplied by a fixed amount. Meanwhile, these are melted and kneaded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electricity, automobiles, machines,
The present invention relates to a method for producing a polyamide resin composition which is applied as a molded product useful in miscellaneous goods and other fields.

[0002]

Polyamide has excellent mechanical properties, sliding properties, thermal properties and chemical resistance, and has already been used in electrical, automobile, mechanical,
Widely applied as a useful molded product in other fields such as sundries. However, as is generally well known, polyamide has a high water absorbing property, and in actual use, it has a problem that it absorbs moisture contained in the atmosphere and its mechanical properties and dimensions change.

As a method of solving such a problem, alloying a polyamide and a hydrophobic polymer has been conventionally performed. There are various types of hydrophobic polymers used for such purposes. Among them, polypropylene is the most suitable because it retains the heat resistance of polyamide by alloying and suppresses mechanical properties and dimensional changes due to water absorption. It is one of the widely used hydrophobic polymers.

If polypropylene used for alloying with polyamide is used as it is, it is inferior in compatibility, so that only a very brittle resin composition can be obtained. For this reason, polypropylene used for alloying with polyamide is chemically modified with, for example, an acid anhydride in order to improve compatibility with it. A resin composition having excellent mechanical strength is manufactured by alloying the polypropylene and polyamide modified in this way. Since such a resin composition has improved mechanical properties and dimensional stability in a humidity atmosphere as compared with the case of using polyamide alone, and also retains heat resistance, it has already been used in a wide range of fields.

[0005]

However, since such a resin composition is conventionally produced by melt-kneading a polyamide and a modified polypropylene produced in a separate step using an extruder, at least two steps are required. In other words, the steps of pelletizing, drying, and packaging of each raw material are repeated, wasteful energy and human resources are consumed in addition to raw material loss, and the raw material is forced to have an excessive heat history. In some cases, this is not a preferable method from the standpoint of maintaining the properties of the obtained polyamide resin composition, such as the deterioration of the components of the resin composition.

As described above, a resin composition of polyamide and polypropylene, which has improved mechanical properties and dimensional stability in a humidity atmosphere and is also heat-resistant, can be manufactured at a low energy with a low cost. The method of doing so has been widely desired, but has not been realized.

In view of such circumstances, an object of the present invention is to provide a resin composition of polyamide and polypropylene, which has improved mechanical properties and dimensional stability in a humidity atmosphere and is also heat resistant. It is to provide a method of manufacturing at low cost with less energy.

[0008]

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve such problems, and the gist of the present invention is to provide an extrusion opening at the tip. In the provided single-screw or multi-screw screw type extruder, two or more resin supply openings having different distances from the tip are provided, and the resin supply opening on the side far from the tip is provided.
(1) Polypropylene and (2) at least one unsaturated compound selected from the group of unsaturated carboxylic acids, derivatives of unsaturated carboxylic acids and unsaturated epoxy compounds are quantitatively supplied, and A method for producing a polyamide resin composition, which comprises melt-kneading the polyamide while quantitatively supplying the polyamide to the supply opening.

The polyamide resin composition produced by the method of the present invention is not only produced at low energy and at low cost,
Since the heat history is smaller than that in the conventional method, the constituent components of the resin composition are less deteriorated. Therefore, the obtained polyamide resin composition has not only a good color tone but also excellent mechanical properties as compared with those produced by the conventional method. Moreover, in the method of the present invention, the degree of chemical modification of polypropylene can be freely selected at the time of alloying, so that a suitable polyamide resin composition can be obtained according to the intended use.

In the present invention, in a single-screw or multi-screw screw type extruder having an extrusion opening at the tip, two or more resin supply openings having different distances from the tip are provided. In the supply opening on the side far from the tip (1)
Polypropylene and (2) at least one unsaturated compound selected from the group of unsaturated carboxylic acids, unsaturated carboxylic acid derivatives and unsaturated epoxy compounds, and (3) if necessary, a radical generator are quantitatively supplied. The polyamide is quantitatively supplied to the supply opening near the tip. Further, in some cases, an opening is further provided between these supply openings or between both supply openings and the tip end, and degassing is performed from this opening to discharge the gas component to the outside of the extruder system. It is also possible to do so. In this case, unreacted substances and low molecular weight decomposition products contained in the obtained resin composition are removed,
It may be preferable for improving its performance. Further, an opening may be provided between the above-mentioned both supply openings or between them or between them and the tip, and a reinforcing material or the like may be blended if necessary.

The extruder used in the present invention comprises a single-screw or multi-screw screw type extruder having an extrusion opening at the tip and two or more openings having different distances from the tip. The machine is not particularly limited as long as it is a machine, but the most general and preferably used is a twin-screw extruder. In the case of such a twin-screw extruder, the rotation directions of the two-screw screws may be the same or different, and these can be arbitrarily selected. However, in the present invention, since the resin is melted and kneaded in the extruder and the chemical reaction or the chemical interaction is performed, a certain residence time is required for the reaction or the interaction. Therefore, it is desirable that the extruder used in the present invention has a residence time (time from the time of first resin supply) of at least 30 seconds.

In the production method of the present invention, polypropylene, an unsaturated compound and the like and polyamide are supplied from different supply openings, but the respective supply methods are not particularly limited. Both constituents may be individually metered and quantitatively supplied, or other constituents may be mixed in advance with each constituent as required and then quantitatively supplied.

In the production method of the present invention, the deaeration performed between the two supply openings used as the case may be or the openings provided between the supply openings and the tip is substantially unreacted unsaturated carbon. It suffices that the acid, the unsaturated carboxylic acid derivative or the unsaturated epoxy compound and other gas components are discharged to the outside of the system of the extruder, and it may be open to the atmosphere, but it is preferable to reduce the pressure. When the pressure is reduced, unreacted unsaturated compounds and other gas components are effectively discharged out of the system.

In the production method of the present invention, from the supply opening for supplying the polypropylene and the unsaturated compound to the supply opening for supplying the polyamide is a chemical modification step of polypropylene, and the cylinder temperature during this step is 20.
It is preferably selected in the range of 0 ° C to 350 ° C. A relatively high cylinder temperature is selected for short residence times and a relatively low cylinder temperature for long residence times. After the supply opening for supplying the polyamide, in the alloying step of the modified polypropylene and the polyamide, the cylinder temperature may be the same as or lower than the above temperature, but higher than the above temperature. It is desirable that it is selected in the range of 220 ° C to 370 ° C. A relatively high cylinder temperature is chosen for short residence times and a relatively low cylinder temperature for long residence times.

The polyamide used in the present invention means a polymer having an amide bond composed of an amino acid, a lactam or a diamine and a dicarboxylic acid. To give an example of such a polyamide construct, the amino acids include 6-aminocaproic acid, 11-aminoundecanoic acid,
12-aminododecanoic acid, para-aminomethylbenzoic acid and the like. As the lactam, ε-caprolactam, ω-
For example, laurolactam. As diamine, tetramethylenediamine, hexamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4
-/ 2,4,4-trimethylhexamethylenediamine,
5-methylnonamethylenediamine, 2,4-dimethyloctamethylenediamine, metaxylylenediamine, paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1-amino-3-aminomethyl-3,
5,5-trimethylcyclohexane, 3,8-bis (aminomethyl) tricyclodecane, bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4- Examples include aminocyclohexyl) propane, bis (aminopropyl) piperazine, and aminoethylpiperazine. Examples of the dicarboxylic acid include adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5- There are sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, diglycolic acid and the like.

Preferred as the polyamide used in the present invention are polycaproamide (nylon 6), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide. (Nylon 610), polyhexamethylene dodecamide (nylon 612), polyundecamethylene adipamide (nylon 116), polyundecane amide (nylon 11), polydodecane amide (nylon 12), polytrimethylhexamethylene terephthalamide ( Nylon TMDT), polyhexamethylene isophthalamide (nylon 6I), polyhexamethylene terephthalamide / isophthalamide (nylon 6T / 6
I), polycapronamide / hexamethylene terephthalamide (nylon 6 / 6T), polyhexamethylene adipamide / hexamethylene terephthalamide (nylon 6
6 / 6T), polybis (4-aminocyclohexyl) methane dodecamide (nylon PACM12), polybis (3-methyl-4-aminocyclohexyl) methanodedecamide (nylon dimethyl PACM12), polymethaxylylene adipamide (nylon MXD6), poly Undecamethylene terephthalamide (nylon 11T), polyundecamethylene hexahydroterephthalamide (nylon 11T (H)), bis (4-aminocyclohexyl) methane tere / isophthalate (nylon PACM /
TPA / IPA) and bis (3-methyl-4-aminocyclohexyl) methane / hexamethylenediamine / I
PA / TPA copolymer (nylon dimethyl PACM / H
MDA / TPA / IPA), and also copolyamides and mixed polyamides thereof. Among them, nylon 6, nylon 46, nylon 66, nylon 6T / 6I, nylon 6 / 6T, nylon 66/6 are particularly preferable.
T, a copolyamide of these, and a mixed polyamide.

The polyamide used here is usually produced by a known method, for example, a melt polymerization method. The relative viscosity of the polyamide used in the present invention is not particularly limited, but the solvent is phenol / tetrachloroethane = 60.
/ 40 (weight ratio), temperature 25 ° C, concentration 1g / dl
It is preferable that the relative viscosity obtained under the condition of is in the range of 1.5 to 5.0.

The content of amino groups and carboxyl groups contained in the polyamide used in the present invention is preferably in the range of 10 to 150 equivalents / 10 ⁶ g. The amino group and the carboxyl group are preferably present in a specific amount because they are expected to chemically react or chemically interact with other components constituting the resin composition when the resin composition is produced by melt-kneading. . The amino group content is determined by dissolving a sample in m-cresol and titrating with p-toluenesulfonic acid by a conventional method. The content of the carboxyl group is determined by dissolving the sample in benzyl alcohol and titrating with potassium hydroxide according to a conventional method.

The polypropylene used in the present invention is a crystalline polypropylene, and besides propylene homopolymer, propylene and, for example, ethylene and butene-
1, including block or random copolymers obtained by copolymerizing α-olefins such as ethylidene norbornene.
The molecular weight of the polypropylene is not particularly limited, but one having a melt index of 0.1 to 100 is preferable in terms of performance, and one having a melt index of 0.5 to 40 is particularly preferable. A homopolymer, a block or a random copolymer of propylene can be obtained, for example, by reacting in the presence of a combination catalyst of titanium trichloride and an alkylaluminum compound, which is usually called a Ziegler-Natta type catalyst.

Specific examples of the unsaturated carboxylic acid used in the present invention include acrylic acid, α-ethylacrylic acid, methacrylic acid, maleic acid, fumaric acid, halogenated maleic acid, citraconic acid and tetrahydrophthalic acid. , Methyltetrahydrophthalic acid, halogenated citraconic acid, crotonic acid, halogenated crotonic acid, itaconic acid, halogenated itaconic acid, cis-4-cyclohexene-1,2-
Dicarboxylic acid, endo-bicyclo- [2,2,1] -5
-Heptene-2,3-dicarboxylic acid, methyl-endo-
Cis-bicyclo- [2,2,1] -5-heptene-2,
3-dicarboxylic acid, endo-bicyclo- [2,2,1]
-1,2,2,2,7,7-hexachloro-2-heptene-5,6-dicarboxylic acid and the like can be mentioned.

The unsaturated carboxylic acid derivative used in the present invention is a compound which is chemically derived from an unsaturated carboxylic acid, for example, an unsaturated carboxylic acid anhydride, ester, amide, imide or metal salt. including.

Specific examples of the unsaturated epoxy compound used in the present invention include glycidyl acrylate, glycidyl methacrylate, itaconic acid monoglycidyl ester, itaconic acid diglycidyl ester, butene tricarboxylic acid monoglycidyl ester, butene tricarboxylic acid diglycidyl ester. , Butenetricarboxylic acid triglycidyl ester, p-styrenecarboxylic acid glycidyl ester, allyl glycidyl ether, 2-methylallyl glycidyl ether, styrene p-glycidyl ether, p-glycidyl styrene, 3,4-epoxy-1-
Butene, 3,4-epoxy-3-methyl-1-butene,
3,4-epoxy-1-pentene, 3,4-epoxy-
Mention may be made of 3-methyl-1-pentene, 5,6-epoxy-1-hexene and vinylcyclohexene monoxide.

Examples of the unsaturated carboxylic acid, the derivative of the unsaturated carboxylic acid, and the unsaturated epoxy compound most preferably used in the present invention include maleic anhydride and endo-bicyclo- [2,2,1] -5-heptene. There are 2,3-dicarboxylic acid anhydride, glycidyl acrylate, glycidyl methacrylate and the like.

The radical generator optionally used in the present invention is used as a reaction initiator or a crosslinking agent, and is typically an organic peroxide or an azo compound.
Specific examples of the organic peroxide include ketone oxides, diacyl peroxides, hydroperoxides,
Examples include dialkyl peroxides and peroxyketals. Specific examples of the organic peroxide include parachlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tertiary butyl cumyl peroxide, ditertiary butyl peroxide, dicumyl peroxide, benzoyl peroxide, 2,5-
Dimethyl-2,5-di (tert-butylperoxy) hexyne-3,2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, tert-butyl hydroperoxide, cumene hydroperoxide, There are 2,5-dimethylhexa-2,5-dihydroperoxide, acetyl peroxide, octanoyl peroxide, 3,5,5-trimethylhexanoyl peroxide and the like. Azobisisobutyronitrile is a specific example of the azo compound.

The compounding amount of polypropylene, which is a constituent of the polyamide resin composition of the present invention, is preferably 1 to 80 parts by weight, and the amount is appropriately selected depending on the purpose. The amount of at least one unsaturated compound selected from the group of unsaturated carboxylic acids, derivatives of unsaturated carboxylic acids and unsaturated epoxy compounds is preferably 0.05 to 5 parts by weight.

The amount of the radical generator used in the present invention, if necessary, is preferably less than 3 parts by weight.

The blending amount of the polyamide constituting the resin composition of the present invention is preferably 20 to 99 parts by weight, and the amount is appropriately selected according to the purpose.

The resin composition produced by the method of the present invention may further contain other polymers, if necessary, as long as the characteristics thereof are not significantly impaired. In this case, the compounding amount is 3
It is preferably 0% by weight or less. Such other polymers include polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyarylate,
Examples include polysulfone, polyether sulfone, polyether ketone, polyether ether ketone, polyetherimide, polyphenylene sulfide, ABS, PMMA, polyvinyl chloride, phenoxy resin, liquid crystal polymer, and polyolefin elastomer. Particularly, the polyolefin elastomer is effective for improving the toughness of the resin composition. Specific examples of such polyolefin elastomers include ethylene-propylene copolymers, ethylene-butene-1 copolymers, ethylene-propylene-diene copolymers, styrene-butadiene copolymers and hydrogenated products thereof, styrene-isoprene copolymers. There are coalesces and hydrogenated products thereof.

The resin composition produced by the method of the present invention includes pigments, heat stabilizers, antioxidants, weather resistance agents, flame retardants, plasticizers, mold release agents, reinforcing materials, etc. as long as the characteristics are not significantly impaired. It is also possible to add. Examples of such heat stabilizers and antioxidants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds and mixtures thereof. As the weather resistance agent, general benzophenones and benzotriazoles are used.
As the flame retardant, a general phosphorus-based flame retardant or a halogen-based flame retardant is used. As the reinforcing material, clay, talc, calcium carbonate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, asbestos, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, aluminum hydroxide, Calcium hydroxide, barium sulfate, potassium alum, sodium alum, iron alum, glass balloon, carbon black, zinc oxide, antimony trioxide,
Examples thereof include boric acid, borax, zinc borate, zeolite, hydrotalcide, metal fibers, metal whiskers, ceramic whiskers, potassium titanate, ticker boron, mica, graphite, glass fibers and carbon fibers. These are arbitrarily blended according to the purpose.
In this case, these can be supplied together with other raw materials through an arbitrary opening, or can be supplied through a newly provided opening.

The polyamide resin composition obtained by the method of the present invention suppresses changes in mechanical properties and dimensions due to water absorption,
Further, since it has improved heat resistance and is manufactured at low cost with less energy, it can be a useful molded product in a wide variety of fields such as electricity, automobiles, machinery, sundries and the like.

[0031]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
The measuring methods and raw materials used in Examples and Comparative Examples are as follows.

1. Bending Strength and Flexural Modulus ASTM D79 using a 1/8 inch thick bending test piece
Bending strength and bending elastic modulus were measured based on 0. 2. Izod impact strength Using the above test piece, Izod impact strength was measured based on ASTM D256. 3. Heat Distortion Temperature (HDT) The heat distortion temperature (HDT) was measured based on ASTM D648 using the above test piece. The load is 4.5 kg / cm
Went in ² . 4. Yellow-index JIS SZ-Σ80 colorimeter manufactured by Nippon Denshoku Co., Ltd.
The yellow index on the surface of the test piece was measured based on K7103. 5. Dimensional change Using a square test piece with a thickness of 2 mm and a width of 50 mm, 60
The thickness and vertical and horizontal dimensional changes after the treatment for 168 hours under the conditions of ° C and 95% RH were measured, and the average value was taken as the dimensional change. 6. Bending strength and elastic modulus after moisture absorption treatment 1/8 inch bending test piece obtained by injection molding was
After treatment for 168 hours under the condition of 95% RH, bending strength and elastic modulus were measured in the same manner as in the above 1. 7. Moisture Absorption Rate Using the same test piece as above, the moisture absorption rate was determined from the weight change after the same moisture absorption treatment.

8. Raw materials Nylon 6: A1030BRL (Unitika Ltd.) Nylon 66: A125 (ICI Corp.) Nylon 46: F5000 (Unitika Corp.) Unmodified polypropylene: Y203 (Tonen Kagaku Corp.)

Examples 1 to 8 A co-rotating twin-screw extruder (made by Ikegai Steel Co., Ltd., PCM45) having an extrusion opening at the tip and two supply openings having different distances from the tip. Mold twin-screw extruder) was used.
The opening is defined as a first opening on the side farther from the tip and a second opening on the side closer to the tip, and the constituent components of the resin composition are shown in Tables 1 and 2 from the respective openings at the blending composition ratios shown in Tables 1 and 2. Supplied.

The cylinder temperature of the extruder is 280 ° C. from the first opening to the second opening, and 260 ° C. when nylon 6 is used as polyamide after the second opening.
When nylon 66 is used, it is 280 ° C, nylon 46
When used, the temperature was 300 ° C. In this case, the average residence time in the extruder was 119 seconds.

Each polyamide resin composition produced by melt-kneading with an extruder was cut into pellets by a conventional method. The obtained pellets of each polyamide resin composition were molded using an injection molding machine (made by Nippon Steel Co., Ltd., J100S molding machine) to obtain each test piece. Various performance evaluations were performed using this. The cylinder temperature of the molding machine is 260 ° C. for a resin composition using nylon 6 and nylon 6
In the case of 6, the temperature was 280 ° C, and in the case of nylon 46, the temperature was 300 ° C. The performance of each of the obtained polyamide resin compositions is listed in Tables 1 and 2.

[0037]

[Table 1]

[0038]

[Table 2]

Comparative Examples 1-3 Nylon 6, Nylon 66 and Nylon 4 for comparison
The performances of 6 alone are shown in Table 3 as Comparative Examples 1 to 3.

[0040]

[Table 3]

Comparative Examples 4 to 6 The same twin-screw extruder as in Examples 1 to 8 (made by Ikegai Steel, PCM4
5 type twin screw extruder) 0.5 parts by weight of maleic anhydride to 50 parts by weight of polypropylene through the first opening,
A mixture having a composition of 0.02 part by weight of benzoyl peroxide was melt-kneaded at a cylinder temperature of 280 ° C. and extruded, and this was cut into modified polypropylene pellets. The obtained modified polypropylene and polyamide were mixed at the compounding ratio shown in Table 4, and then melt-kneaded using the same extruder, extruded and cut to obtain pellets of each resin composition. In this case, the cylinder temperature of the extruder is 260 ° C. when nylon 6 is used and 280 when nylon 66 is used.
℃, when using nylon 46, it was 300 ℃. The obtained pellets of each resin composition were molded using an injection molding machine (made by Nippon Steel Co., Ltd., J100S molding machine) to obtain each test piece. Various performance evaluations were performed using these. The cylinder temperature of the molding machine is 260 ° C. for the resin composition using nylon 6 and 28 for nylon 66.
The temperature was 0 ° C., and that of nylon 46 was 300 ° C. The properties of these polyamide resin compositions are listed in Table 4.

[0042]

[Table 4]

The polyamide resin composition produced in this example has a lower moisture absorption rate as compared with the case of using the polyamide alone (Comparative Examples 1 to 3 in Table 3), as specifically listed in Tables 1 and 2. Therefore, changes in mechanical properties and dimensions due to water absorption were significantly reduced. Further, the polyamide resin composition shown in the examples produced by the energy-saving and inexpensive method of the present invention, compared with that produced by the method using the polypropylene previously modified in another step, represented by a yellow index. Not only was it excellent in color tone, but it was also excellent in mechanical performance.

[0044]

As is clear from the above description, according to the method of the present invention, a polyamide and a polypropylene having improved mechanical properties and dimensional stability in a humidity atmosphere and improved heat resistance are obtained. It has become possible to obtain excellent operational effects such as being able to produce the resin composition of 1) at low cost with less energy.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location // C08L 23/26 LDA 7107-4J B29K 23:00 77:00 (72) Inventor Shinichiro Katahira Kyoto 23, Uji-Kozakura, Uji-shi, Central Unit, Central Research Institute, Unitika Co., Ltd. (72) Inventor, Mioko Watanabe, 23, Uji-Kozakura, Uji City, Uji City, Central Unit, Central Research Co., Ltd.

Claims (1)

[Claims] 1. In a single-screw or multi-screw screw type extruder having an extrusion opening at the tip, two or more resin supply openings having different distances from the tip are provided, and the tip is provided. In the supply opening on the side remote from (1) polypropylene
(2) At least one selected from the group of unsaturated carboxylic acids, derivatives of unsaturated carboxylic acids and unsaturated epoxy compounds
A method for producing a polyamide resin composition, which comprises melt-kneading a certain amount of an unsaturated compound in a constant amount, and supplying a constant amount of polyamide in a supply opening near the tip portion while melt-kneading these.