JPH0873539A - Thermoplastic resin composition and molding material - Google Patents

Abstract

PURPOSE: To obtain a thermoplastic resin composition excellent in heat resistance, rigidity, moistureproofness, coatability, surface properties, etc., without impairing a balance among them and also excellent in weld strength and moldability by mixing a specified modified propylene polymer with a specified polyamide resin. CONSTITUTION: This composition comprises desirably 5-95wt.% propylene polymer modified with a vinyl monomer having a polar functional group, desirably epoxy or carboxyl group (e.g. PP modified with glycidyl methacrylate) and desirably 95-5wt.% polyamide resin (e.g. nylon 6) in which the amount of the terminal amino groups is larger than that of the terminal carboxyl groups, and desirably the molar ratio of the terminal amino groups to the terminal carboxyl groups is 1.1 or above.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermoplastic resin composition comprising a modified propylene polymer and a specific polyamide resin, which is excellent in moldability and weld strength.

[0002]

2. Description of the Related Art Polyamide resins are excellent in wear resistance, electrical characteristics, heat distortion resistance and mechanical strength.
It is widely used as an engineering resin in various mechanical parts materials, but has drawbacks such as insufficient impact resistance and flexibility, and high water absorption. In particular, water absorption is a problem, and the water-absorbed polyamide resin is not preferable because bubbles tend to be whitened when molding is performed, and not only the mechanical strength is significantly lowered by water absorption but also the dimensional change and Problems such as deformation also occur. Since the polyamide resin has such drawbacks, its application as an engineering resin is limited, and it is often impossible to take advantage of the excellent characteristics inherent to the polyamide resin.

On the other hand, polypropylene has a low specific gravity and shows almost no water absorption, but its mechanical strength,
In particular, there is a drawback that the physical properties at high temperature are insufficient.

Therefore, attempts have been made to use polyamide resins and polypropylene in combination in order to improve the drawbacks of these resins. However, even if the polyamide resin and the polypropylene are simply blended by melt-kneading or the like, the compatibility between the two is poor, so that layer peeling occurs and only a product having poor surface gloss and mechanical strength can be obtained. To improve this compatibility, for example, a composition using polypropylene obtained by modifying a part or all of polypropylene with carboxylic acid or its anhydride (Japanese Patent Publication No. 45-
30943, JP-A-60-118735), and a composition using polypropylene obtained by further modifying the acid-modified polypropylene with a silane compound (Japanese Patent Publication No.
No. 74698) has been proposed, these conventional compositions have improved compatibility in terms of compatibility due to the inclusion of modified polypropylene, but the effect of improving mechanical properties such as strength was not always sufficient. .

We have previously solved the problems of these compositions to obtain a resin composition having excellent heat distortion resistance and mechanical strength of polyamide resin and low water absorption property of polypropylene. Blending a modified propylene-based polymer resin obtained by melt-kneading polymerization of an aromatic vinyl monomer and a polar functional group-containing vinyl monomer in the presence of a propylene-based polymer in a molten state, and a polyamide resin Therefore, it has been proposed that the above object can be achieved (Japanese Patent Laid-Open No. 5-287163).

[0006] However, although the above proposal shows an effect of improving mechanical properties such as water absorption or flexural strength, depending on the use, it is said that weldability is said to be a defect of moldability due to thickening of the composition and microdispersion type alloy. The low strength was not always sufficient.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the problems associated with conventional compositions, such as inferior moldability and weld strength, and improves the compatibility of polyamide resin with polypropylene, thereby improving the polyamide composition. An object of the present invention is to obtain a resin composition having excellent abrasion resistance, electrical characteristics, heat distortion resistance and mechanical strength of a resin, and low water absorption characteristics of polypropylene.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned drawbacks of the conventional method, the present inventors have found that when a modified propylene polymer (A) and a polyamide resin are compounded, the end By using the polyamide resin (B) having a high amino group ratio, it has been found that the above object is achieved,
The present invention has been completed.

That is, according to the present invention, a polar functional group-containing vinyl monomer-modified propylene polymer (A) and a polyamide resin (B) having more terminal amino groups than terminal carboxyl groups.
A thermoplastic resin composition, more preferably 5 to 95% by weight of a polar functional group-containing vinyl monomer-modified propylene polymer (A), and preferably a ratio of terminal amino groups to terminal carboxyl groups. Of the polyamide resin (B) of 1.1 or more, preferably 95 to 5% by weight
And a thermoplastic resin composition and a molding material. The present invention will be described in detail.

(Structure) The modified propylene polymer (A) of the present invention is modified with a polar functional group-containing vinyl monomer, and may be any propylene polymer having a polar functional group. Preferably, the propylene-based polymer is obtained by polymerizing both an aromatic vinyl monomer and a polar functional group-containing vinyl monomer, wherein the aromatic vinyl monomer and the polar functional group-containing vinyl monomer are It is a graft-polymerized propylene-based polymer. The aromatic vinyl monomer-derived component in the modified propylene polymer (A) is preferably 50% by weight or less, more preferably 1 to 35% by weight.
The content of the polar functional group-containing vinyl monomer-derived component is preferably 10% by weight or less, more preferably 0.1 to 5% by weight.

The production method of (A) is as follows: a granular, powdery, flake-like, granulate-like, or porous propylene-based polymer with an aromatic vinyl monomer and a polar functional group-containing vinyl monomer. Any other method such as a polymerization reaction method of impregnating with a radical polymerization initiator and irradiating high-energy ionizing radiation under an inert gas may be used, but preferably a powder or pellet-shaped propylene-based polymer is supplied to the extruder. While applying pressure, preferably 130 to 250
The crystalline propylene-based polymer is melted by heating at 0 ° C., and the aromatic vinyl monomer and the polar functional group-containing vinyl monomer are melt-kneaded and polymerized preferably in the presence of a radical initiator. This is a method in which the strands discharged from the are cooled and pelletized using a pelletizer.

The propylene-based polymer as the raw material of (A) is a propylene homopolymer and a copolymer of propylene as a main component with another olefin or an ethylenic vinyl monomer (preferably 75% by weight or more of propylene). And is specifically a isotactic polypropylene, a propylene-ethylene copolymer, a propylene-butene copolymer, or the like. 2 of these propylene-based polymers
A mixture of more than one species can be used. Further, other polymers can be used as long as the properties of the propylene polymer are not impaired.

The polar functional group-containing vinyl monomer used for modification is a copolymerizable epoxy group-containing vinyl monomer,
Examples thereof include a hydroxyl group-containing vinyl monomer, a carboxylic acid group-containing vinyl monomer, and an oxazoline group-containing vinyl monomer.
Preferably, it is an epoxy group-containing vinyl monomer or a carboxyl group-containing vinyl monomer.

Examples of the epoxy group-containing vinyl monomer include glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, and methacryl glycidyl ether, which may be used alone or in combination. Glycidyl methacrylate is particularly preferable.

Examples of the hydroxyl group-containing vinyl monomer include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate and 2
-Hydroxybutyl methacrylate and the like can be used alone or in combination.

The carboxylic acid group-containing vinyl monomer includes, for example, acrylic acid, methacrylic acid, maleic anhydride, maleic acid and the like and alkyl esters thereof, and these are used alone or as a mixture thereof.

The vinyl monomer containing an oxazoline group includes 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-oxazoline and the like. There is.

As the aromatic vinyl monomer used in combination with the polar functional group-containing vinyl monomer, for example, styrene, methylstyrene, vinyltoluene, vinylxylene, ethylvinylbenzene, isopropylstyrene, chlorostyrene, dichlorostyrene, Bromostyrene and the like,
Used alone or as a mixture. Preferred is styrene.

The amount of the aromatic vinyl monomer added is preferably 50% by weight or less, more preferably 1 to 35% by weight, based on the propylene polymer. If it exceeds 50% by weight, the performance of polypropylene is impaired, which is not preferable. Further, the aromatic vinyl monomer is to prevent the lowering of the molecular weight of the modified propylene-based polymer and to improve the compatibility with the polyamide resin, at least the same amount or more as the addition amount of the polar functional group-containing vinyl monomer,
It is preferable to add 1 to 5 times the amount.

The addition amount of the polar functional group-containing vinyl monomer is
The propylene polymer content is preferably 10% by weight or less, more preferably 0.1 to 5% by weight. If it exceeds 10% by weight, not only the modified propylene polymer may have a low molecular weight but also the adhesiveness, water absorption and mechanical properties of the composition may be adversely affected, which is not preferable.

The radical initiator is easily dissolved in the aromatic vinyl monomer due to the features of the present invention, and the reaction is carried out at the melt-kneading temperature of the propylene-based polymer.
The decomposition temperature is preferably 130 to obtain a half-life of minutes.
It is desirable that the temperature is 250 ° C. To give a specific example,
t-butyl peroctate, bis (t-butyl peroxy) trimethylcyclohexane, cyclohexanone peroxide, benzoyl peroxide, dicumyl peroxide, t-butyl perbenzoate, dimethyl
Examples include di (t-butylperoxy) hexane and dimethyldi (t-butylperoxy) hexyne.

The amount of the radical initiator used is preferably 0.1 to 10 relative to 100 parts by weight of all vinyl monomers.
It is good to set it as 1 part by weight, more preferably 1 to 5 parts by weight.

As other additives, a polypropylene polymer is a radical-disintegrating polymer unlike polyethylene, so that it is preferable to add a stabilizer. However, it is necessary to consider the kind and addition amount so as not to hinder the polymerization of the aromatic vinyl monomer. For example, pentaerythrityl-tetrakis ((di-t-butyl-hydroxyphenyl) propionate), ocdecyl (di-t-butyl-hydroxyphenyl) propionate, thiobis (methyl t-).
Butylphenol), hindered phenolic stabilizers such as trimethyl-tris (di-t-butylhydroxybenzyl) benzene, tetrakis (di-t-butylphenyl)
There are phosphorus-based stabilizers such as biphenylene phosphite and tris (di-t-butylphenyl) phosphite, metal soaps such as zinc stearate and calcium stearate, and antacid adsorbents such as magnesium oxide and hydrotalcite.
The amount of the stabilizer used is preferably 0.01 to 1 part by weight, more preferably 0.05 to 0.5 part by weight, based on 100 parts by weight of the propylene polymer.

To carry out a melt-kneading polymerization reaction of a propylene-based polymer with an aromatic vinyl monomer and a polar functional group-containing vinyl monomer, preferably, a continuous container such as a Banbury mixer or an extruder is continuously kneaded. You can do it with a machine. The extruder is more preferable than the industrial production such as granulation. Further, in the twin-screw extruder, it is easier to control supply of reactants, kneading, polymerization time and the like.

The vinyl monomer may be mixed with the propylene-based polymer in advance and then supplied to the extruder.
Although it may be supplied to the propylene-based polymer in a molten state using a liquid feeder, it is preferable that the propylene-based polymer is mixed and impregnated in advance.

The radical initiator may be added by dissolving it in the vinyl monomer in advance, or may be added to the mixture of the propylene polymer and the vinyl monomer by using the liquid feeder. The stabilizer is preferably mixed in advance with the propylene-based polymer by using a Henschel mixer or the like.

Since the propylene-based polymer is a radical-disintegrating polymer unlike the ethylene-based polymer, if the polymer is simply melt-heated, the molecular weight is apt to decrease due to the breaking of the main chain.
Therefore, a modified propylene-based polymer having a low molecular weight can be obtained even if a polar functional group-containing vinyl monomer is melt-kneaded in the presence of an organic peroxide. However, according to the melt-kneading reaction method, the aromatic vinyl monomer and the polar functional group-containing vinyl monomer are efficiently graft-reacted by reacting in the presence of a stabilizer, and there is no decrease in molecular weight, and the polyamide The modified propylene polymer (A) having improved compatibility with the resin can be used.

The polyamide resin (B) in the present invention is
A polyamide resin having a high concentration of amino groups in the terminal groups, preferably having a ratio of terminal amino groups to terminal carboxyl groups of 1.1 or more, and particularly preferably a polyamide resin having 1.1 to 5 times as many terminal amino groups as the terminal carboxyl groups. Is. The amount of amino groups in the polyamide resin (B) is preferably 20 to 150 mmol / kg, and the amount of carboxyl groups is preferably 20 to 80 mmol / kg.

The polyamide resin is an acid amide (--CONH).
Polymer compounds having-) as a repeating unit include those obtained by ring-opening polymerization of lactam, those obtained by polycondensation of diamine and dibasic acid, and those obtained by polycondensation of aminocarboxylic acid, depending on the polymerization mode. In general, even when it is formed by ring-opening polymerization of lactam, or when it is formed by polycondensation of diamine and dibasic acid or polycondensation of aminocarboxylic acid, impurities and side reactions can be ignored and no additive is added. Produces only a carboxyl group and an amino group at the polymer terminal, and both of them are equimolar. However, polyamides having different ratios of terminal functional groups can be prepared by adding carboxylic acid or amine as an additive.

Reacting with a carboxyl group by adding an appropriate amount of a chain transfer agent such as metaxylylenediamine, paraxylylenediamine, hexamethylenediamine or dodecamethylenediamine during the production of the polyamide resin or after the polymerization reaction for polyamidation. A polyamide resin having a high amino group concentration can be obtained by reacting with a compound having a group.

The molecular weight of the polyamide resin is not particularly limited, but usually the relative viscosity η _r (JIS K681
According to 0, those having a value of 0.5 or more (measured in 98% sulfuric acid) are preferable, and those having 2 to 3.5 are more preferable.

As the polyamide resin (B) of the present invention,
For example, polylactams such as nylon 6, nylon 11 and nylon 12, polyamides obtained from dicarboxylic acids and diamines such as nylon 46, nylon 66, nylon 610 and nylon 612, nylon 6/66, nylon 6/612 and nylon 6 / Examples thereof include copolymer amides such as 6T (T is a terephthalic acid component), polyether amides, polyester amides, polyester ether amides, and the like, and among these, nylon 6 and nylon 66 are preferable.

The composition ratio of the composition of the present invention is such that the modified propylene polymer (A) is preferably 5 to 95% by weight, particularly preferably 20 to 85% by weight, and the polyamide resin (B) is preferably 95 to 5% by weight. And particularly preferably 80 to 15% by weight
Is. In the composition, if the modified propylene polymer (A) is less than 5% by weight, the modified propylene polymer (A) cannot obtain the effect of improving the low water absorption and the molding processability. On the other hand, if the polyamide resin is less than 5% by weight, the effect of improving the abrasion resistance, mechanical properties, heat distortion resistance, etc. by the polyamide resin cannot be obtained. If the amino group ratio is less than 1.1, the molding processability and weld strength cannot be improved, and if it is more than 5, mechanical properties such as impact resistance and heat deformability are adversely affected.

In addition to these essential components, additional components can be added to the composition of the present invention within a range that does not impair the effects of the invention.

Unmodified polypropylene or also unmodified nylon may be added as an additional component. In that case, the addition time may be either first mixing with the modified propylene polymer (A) or after mixing with the polyamide resin (B), but the addition amount of the unmodified polypropylene is preferably the modified propylene polymer (A). 900 for 100 parts by weight
It should be less than or equal to parts by weight.

The amount of the unmodified polyamide resin added is preferably 9 with respect to 100 parts by weight of the modified polyamide resin (B).
It should be below 100 parts by weight.

As other additional components, for example, other thermoplastic resins, rubbers, inorganic fillers, pigments, various stabilizers (antioxidants, light stabilizers, antistatic agents, antiblocking agents, lubricants), etc. Is.

The composition of the present invention is produced by dry blending these components with a Henschel mixer, a V blender, a ribbon blender, a tumbler blender, etc.
This mixture is melt-mixed with a kneading machine such as a single-screw or twin-screw extruder, a roll, a Banbury mixer, pelletized or crushed, and then subjected to molding. Molding is injection molding, hollow molding,
Any method such as extrusion molding can be adopted.

By doing so, the composition of the present invention is
A non-water-absorbing material, heat resistance, rigidity, moisture resistance, paintability, excellent surface property, etc. in a well-balanced manner, and also a thermoplastic resin composition having excellent weld strength and molding processability, and can be used as an excellent molding material. it can.

[0040]

EXAMPLES Next, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following, all parts and% are based on weight unless otherwise specified.

The test methods for the physical properties of the composition and the target physical properties are as follows. Melt index (MI): JIS K7210 (2.16 kg, 230 ° C) Moldability target value 1 to 25 Layered peeling: The molded article was immersed in toluene to visually judge the presence or absence of layered peeling Thermal deformation: Measurement JIS K7202 (Vicat temperature load 4kg) Target value 130 ℃ or more Bending strength: Measurement ASTM D790 Target value 1.5 × 10 ⁴ kg
/ Cm ² or more weld strength: measured ASTM D256 Izod impact value (23 ℃)
Target value 6 or more Impact strength: Measured ASTM D256 Izod impact value (23 ° C, with notch) Target value 6 or more Water absorption rate: 120 at 23 ° C using injection test piece (104 × 50 × 2mm)
Calculated by the following formula after immersion in time

Note) The following substances were used as abbreviations in the examples. PP: polypropylene, GMA: glycidyl methacrylate, MAh: maleic anhydride, SM: styrene

Example 1 A 30 mm twin-screw extruder manufactured by Brabender (Germany) was set to a barrel temperature of 240 ° C. (however, a feeder section 180 ° C.) and a die temperature of 240 ° C.
"Modified polypropylene 1" (MI = 2.5, PP / GM
A / SM = 92 / 2.5 / 5.5) 300 parts and "Modification 6
Nylon A "(relative viscosity 2.3, amino group 97 mmol
/ Kg, 47 mmol / kg of carboxyl group, and 700 parts of amino group / carboxyl group ratio of 2.0),
This was kneaded and pelletized by using the above twin-screw extruder. Using the IS50AM injection molding machine manufactured by Toshiba, test pieces were prepared from the obtained pellets at a resin temperature of 270 ° C., and various physical properties were evaluated. The results are shown in Table 1.

Example 2 In the production of the composition of Example 1, "modified polypropylene 1" (MI = 2.5, PP /
GMA / SM = 92 / 2.5 / 5.5) 300 parts and "modified 6 nylon A" (relative viscosity 2.3, amino group 97 mm)
ol / kg, carboxyl group 47 mmol / kg) 70
A composition was produced by replacing 0 part with 500 parts of the modified propylene polymer and 500 parts of the nylon, and various physical properties were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3 In the production of the composition of Example 1, "modified 6 nylon A" (relative viscosity 2.3, amino group 97 mmol / kg, carboxyl group 47 mmol / k)
g) The same amount of "modified 6 nylon B" instead of 700 parts
A composition comprising modified polypropylene and nylon in the same manner as in Example 1 except that (relative viscosity 2.2, amino group 110 mmol / kg, carboxyl group 45 mmol / kg, amino group / carboxyl group ratio 2.4) was used. Was manufactured and various physical properties were evaluated. The results are shown in Table 1.

Example 4 In the production of the composition of Example 1, "modified polypropylene 1" (MI = 2.5, PP /
GMA / SM = 92 / 2.5 / 5.5) The same amount of "modified polypropylene 2" (MI = 5, PP) instead of 300 parts
/MAh/SM=93/1.5/5.5) was used to produce a modified polypropylene and a composition in the same manner as in Example 1 to evaluate various physical properties. The results are shown in Table 1.

Comparative Example 1 In the production of the composition of Example 1, "modified 6 nylon A" (relative viscosity 2.3, amino group 97 mmol / kg, carboxyl group 47 mmol / k)
g) As in Example 1 except that the same amount of "6 nylon" (relative viscosity 2.3, amino group 71 mmol / kg, carboxyl group 71 mmol / kg, amino group / carboxyl group ratio 1) was used instead of 700 parts. A modified polypropylene and a composition were produced in the same manner, and various physical properties were evaluated. The results are shown in Table 1.

Comparative Example 2 In the production of the composition of Example 1, "modified 6 nylon A" (relative viscosity 2.3, amino group 97 mmol / kg, carboxyl group 47 mmol / k)
g) The same amount of "modified 6 nylon C" instead of 700 parts
A modified polypropylene and a composition were produced in the same manner as in Example 1 except that (relative viscosity 2.3, amino group 39 mmol / kg, carboxyl group 105 mmol / kg, amino group / carboxyl group ratio 0.37) was used. Various physical properties were evaluated. The results are shown in Table 1.

(Comparative Example 3) In the production of the composition of Example 1, "modified polypropylene 1" (MI = 2.5, PP /
GMA / SM = 92 / 2.5 / 5.5) Same as Example 1 except that the same amount of “HIPOL J400” (homopolypropylene [MFR = 3]: manufactured by Mitsui Petrochemical Co., Ltd.) was used instead of 300 parts. A modified polypropylene and a composition were produced in the same manner, and various physical properties were evaluated. The results are shown in Table 1.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

The present invention comprises a polar functional group-containing vinyl monomer (particularly an epoxy group-containing vinyl monomer or a carboxyl group-containing vinyl monomer) -modified polypropylene and a polyamide resin having a high terminal amino group concentration. By being a composition, it is not only excellent in mechanical properties such as non-water-absorption and impact strength, but also a thermoplastic molding material having good physical properties such as excellent moldability and weld strength particularly useful for precision injection molding of connectors and the like. And can be widely used in the field of molding automotive parts, electronic and home appliances, etc.

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Claims (7)

[Claims] 1. A thermoplastic resin comprising a polar functional group-containing vinyl monomer-modified propylene polymer (A) and a polyamide resin (B) having an amount of terminal amino groups larger than the amount of terminal carboxyl groups. Composition. 2. A modified propylene-based polymer (A) 5 to 95.
2. The thermoplastic resin composition according to claim 1, which is a resin composition composed of 95% by weight of the polyamide resin (B) and 5% by weight of the polyamide resin (B). 3. The thermoplastic resin composition according to claim 1, wherein the polyamide resin (B) has a ratio of terminal amino groups to terminal carboxyl groups (molar ratio) of 1.1 or more. 4. The polyamide resin (B) has a molar ratio of terminal amino groups and terminal carboxyl groups of 1.1: 1 to 5:
The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition is 1. 5. The thermoplastic resin composition according to claim 1, wherein the functional group contained in the modified propylene polymer (A) is an epoxy group or a carboxyl group. 6. A modified propylene-based polymer (A) obtained by melt-kneading and polymerizing an aromatic vinyl monomer and a functional group-containing vinyl monomer with a propylene-based polymer in a molten state. The thermoplastic resin composition according to claim 1, which is a united resin. 7. A molding material comprising the thermoplastic resin composition according to claim 1.